芒果视频下载

基本介紹

刺(ci)胞動物(wu)(wu)(wu)門（Cnidaria）又稱(cheng)刺(ci)細胞動物(wu)(wu)(wu)門，過去(qu)稱(cheng)為(wei)(wei)(wei)(wei)(wei)(wei)(wei)腔腸(chang)動物(wu)(wu)(wu)門（Coelenterata），因為(wei)(wei)(wei)(wei)(wei)(wei)(wei)它的(de)(de)(de)含義適用于(yu)(yu)刺(ci)胞動物(wu)(wu)(wu)及(ji)櫛水(shui)(shui)母(mu)(mu)(mu)(mu)動物(wu)(wu)(wu)，所以現(xian)(xian)多已廢棄(qi)不用。刺(ci)胞動物(wu)(wu)(wu)體(ti)(ti)呈(cheng)輻射或(huo)兩輻射對(dui)稱(cheng)，僅具二胚層，是最(zui)原始(shi)的(de)(de)(de)后生(sheng)(sheng)(sheng)動物(wu)(wu)(wu)。體(ti)(ti)壁(bi)由(you)外(wai)胚層、內胚層和中(zhong)(zhong)(zhong)膠層組成(cheng)。內胚層圍成(cheng)身體(ti)(ti)的(de)(de)(de)整個(ge)(ge)(ge)內腔稱(cheng)消化循環(huan)腔，腔腸(chang)一(yi)端為(wei)(wei)(wei)(wei)(wei)(wei)(wei)口(kou)，他端閉塞，無肛(gang)門。體(ti)(ti)壁(bi)中(zhong)(zhong)(zhong)有(you)(you)刺(ci)細胞。腔腸(chang)動物(wu)(wu)(wu)的(de)(de)(de)骨(gu)(gu)(gu)骼(ge)主(zhu)要為(wei)(wei)(wei)(wei)(wei)(wei)(wei)外(wai)骨(gu)(gu)(gu)骼(ge)，具有(you)(you)支持和保護功(gong)能。多由(you)幾丁質、角質和石灰質構(gou)成(cheng)。在(zai)很多珊(shan)瑚(hu)(hu)蟲(chong)中(zhong)(zhong)(zhong)具有(you)(you)骨(gu)(gu)(gu)針或(huo)骨(gu)(gu)(gu)軸，它們存在(zai)于(yu)(yu)中(zhong)(zhong)(zhong)膠層，或(huo)突出(chu)于(yu)(yu)體(ti)(ti)表面。有(you)(you)無性(xing)和有(you)(you)性(xing)兩種(zhong)生(sheng)(sheng)(sheng)殖(zhi)(zhi)方(fang)式(shi)，并往往出(chu)現(xian)(xian)在(zai)同(tong)一(yi)種(zhong)的(de)(de)(de)生(sheng)(sheng)(sheng)活(huo)史(shi)中(zhong)(zhong)(zhong)，即(ji)水(shui)(shui)螅型(xing)世(shi)代用無性(xing)出(chu)芽生(sheng)(sheng)(sheng)殖(zhi)(zhi)方(fang)式(shi)產生(sheng)(sheng)(sheng)水(shui)(shui)母(mu)(mu)(mu)(mu)型(xing)世(shi)代，而水(shui)(shui)母(mu)(mu)(mu)(mu)型(xing)個(ge)(ge)(ge)體(ti)(ti)脫(tuo)離母(mu)(mu)(mu)(mu)體(ti)(ti)，長大成(cheng)熟(shu)以后，又以有(you)(you)性(xing)生(sheng)(sheng)(sheng)殖(zhi)(zhi)方(fang)式(shi)產生(sheng)(sheng)(sheng)水(shui)(shui)螅型(xing)個(ge)(ge)(ge)體(ti)(ti)，兩個(ge)(ge)(ge)世(shi)代互相(xiang)交替完成(cheng)整個(ge)(ge)(ge)生(sheng)(sheng)(sheng)活(huo)史(shi)。約1萬種(zhong)，可(ke)分為(wei)(wei)(wei)(wei)(wei)(wei)(wei)：水(shui)(shui)螅蟲(chong)綱(gang)(gang)、缽水(shui)(shui)母(mu)(mu)(mu)(mu)綱(gang)(gang)和珊(shan)瑚(hu)(hu)蟲(chong)綱(gang)(gang)3綱(gang)(gang)，一(yi)般認為(wei)(wei)(wei)(wei)(wei)(wei)(wei)水(shui)(shui)螅蟲(chong)綱(gang)(gang)是最(zui)原始(shi)的(de)(de)(de)。絕大部(bu)分海(hai)產，只有(you)(you)少(shao)數種(zhong)類(lei)(lei)產于(yu)(yu)淡水(shui)(shui)，以熱帶和亞熱帶海(hai)洋的(de)(de)(de)淺(qian)水(shui)(shui)區最(zui)豐(feng)富。較小種(zhong)類(lei)(lei)可(ke)作魚類(lei)(lei)食餌，珊(shan)瑚(hu)(hu)骨(gu)(gu)(gu)骼(ge)（如紅珊(shan)瑚(hu)(hu)）可(ke)作工藝品(pin)，古珊(shan)瑚(hu)(hu)和現(xian)(xian)代珊(shan)瑚(hu)(hu)可(ke)形成(cheng)儲油層，海(hai)邊的(de)(de)(de)珊(shan)瑚(hu)(hu)礁可(ke)作天然海(hai)堤；海(hai)蜇(zhe)鹽漬后成(cheng)為(wei)(wei)(wei)(wei)(wei)(wei)(wei)食品(pin)，有(you)(you)些(xie)種(zhong)類(lei)(lei)可(ke)作藥用；有(you)(you)些(xie)浮游水(shui)(shui)母(mu)(mu)(mu)(mu)類(lei)(lei)可(ke)作為(wei)(wei)(wei)(wei)(wei)(wei)(wei)海(hai)流指(zhi)示(shi)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)；但是，有(you)(you)些(xie)大型(xing)水(shui)(shui)母(mu)(mu)(mu)(mu)（如霞水(shui)(shui)母(mu)(mu)(mu)(mu)、根口(kou)水(shui)(shui)母(mu)(mu)(mu)(mu)）在(zai)大量(liang)出(chu)現(xian)(xian)時，會阻塞或(huo)破(po)壞漁網，有(you)(you)的(de)(de)(de)海(hai)葵混于(yu)(yu)漁獲物(wu)(wu)(wu)中(zhong)(zhong)(zhong)，人食后中(zhong)(zhong)(zhong)毒(du)致死。刺(ci)胞動物(wu)(wu)(wu)除極少(shao)數種(zhong)類(lei)(lei)為(wei)(wei)(wei)(wei)(wei)(wei)(wei)淡水(shui)(shui)生(sheng)(sheng)(sheng)活(huo)外(wai)，絕大多數種(zhong)均為(wei)(wei)(wei)(wei)(wei)(wei)(wei)海(hai)洋生(sheng)(sheng)(sheng)活(huo)，多數在(zai)淺(qian)海(hai)，少(shao)數為(wei)(wei)(wei)(wei)(wei)(wei)(wei)深海(hai)種(zhong)，現(xian)(xian)存約11000種(zhong)，分為(wei)(wei)(wei)(wei)(wei)(wei)(wei)3個(ge)(ge)(ge)綱(gang)(gang)：水(shui)(shui)螅綱(gang)(gang)（Hydrozoa）、缽水(shui)(shui)母(mu)(mu)(mu)(mu)綱(gang)(gang)（Scyphozoa）、珊(shan)瑚(hu)(hu)綱(gang)(gang)（Anthozoa）。

形態及特征

肌肉與運動

刺胞動(dong)(dong)(dong)物很(hen)少能(neng)做(zuo)(zuo)主(zhu)動(dong)(dong)(dong)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)移位(wei)運(yun)(yun)(yun)動(dong)(dong)(dong)，運(yun)(yun)(yun)動(dong)(dong)(dong)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)能(neng)力(li)是(shi)很(hen)有(you)(you)(you)限的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)，特別是(shi)水(shui)(shui)螅(xi)型。運(yun)(yun)(yun)動(dong)(dong)(dong)是(shi)由(you)(you)表皮(pi)肌(ji)肉(rou)(rou)細胞中肌(ji)原(yuan)纖維(wei)(wei)(wei)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)收(shou)縮(suo)(suo)(suo)(suo)(suo)(suo)所(suo)(suo)引(yin)起(qi)(qi)。例如(ru)水(shui)(shui)螅(xi)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)身(shen)體可(ke)(ke)做(zuo)(zuo)伸(shen)縮(suo)(suo)(suo)(suo)(suo)(suo)運(yun)(yun)(yun)動(dong)(dong)(dong)，伸(shen)展時體長可(ke)(ke)達(da)15～20mm，收(shou)縮(suo)(suo)(suo)(suo)(suo)(suo)時體長僅0.5mm，這種伸(shen)縮(suo)(suo)(suo)(suo)(suo)(suo)是(shi)爆發式的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)，每5～10分鐘左右爆發一(yi)次，主(zhu)要是(shi)由(you)(you)外皮(pi)肌(ji)細胞的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)縱行肌(ji)原(yuan)纖維(wei)(wei)(wei)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)收(shou)縮(suo)(suo)(suo)(suo)(suo)(suo)所(suo)(suo)引(yin)起(qi)(qi)。身(shen)體一(yi)側的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)肌(ji)原(yuan)纖維(wei)(wei)(wei)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)收(shou)縮(suo)(suo)(suo)(suo)(suo)(suo)可(ke)(ke)引(yin)起(qi)(qi)身(shen)體的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)彎(wan)曲。有(you)(you)(you)時靠彎(wan)曲身(shen)體及(ji)觸手并與基盤(pan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)交替附著而做(zuo)(zuo)翻斛斗式的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)運(yun)(yun)(yun)動(dong)(dong)(dong)。基盤(pan)處粘細胞可(ke)(ke)分泌(mi)大(da)量的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)氣泡，可(ke)(ke)使(shi)(shi)水(shui)(shui)螅(xi)在水(shui)(shui)面(mian)(mian)上(shang)做(zuo)(zuo)短暫的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)漂浮。缽(bo)水(shui)(shui)母(mu)(mu)類(lei)和(he)珊瑚類(lei)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)肌(ji)原(yuan)纖維(wei)(wei)(wei)已(yi)與表皮(pi)細胞分離形(xing)成獨立的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)一(yi)層肌(ji)纖維(wei)(wei)(wei)，例如(ru)水(shui)(shui)母(mu)(mu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)肌(ji)原(yuan)纖維(wei)(wei)(wei)在下(xia)傘(san)(san)面(mian)(mian)及(ji)傘(san)(san)緣(yuan)(yuan)(yuan)形(xing)成薄薄的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)一(yi)層肌(ji)肉(rou)(rou)環，有(you)(you)(you)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)被(bei)輻管分離成片狀，其(qi)纖維(wei)(wei)(wei)有(you)(you)(you)橫紋，它們做(zuo)(zuo)有(you)(you)(you)規律的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)收(shou)縮(suo)(suo)(suo)(suo)(suo)(suo)，使(shi)(shi)傘(san)(san)面(mian)(mian)有(you)(you)(you)節奏(zou)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)收(shou)縮(suo)(suo)(suo)(suo)(suo)(suo)運(yun)(yun)(yun)動(dong)(dong)(dong)。當(dang)傘(san)(san)緣(yuan)(yuan)(yuan)收(shou)縮(suo)(suo)(suo)(suo)(suo)(suo)時，傘(san)(san)緣(yuan)(yuan)(yuan)內的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)水(shui)(shui)被(bei)噴出，由(you)(you)于(yu)反作用力(li)而推動(dong)(dong)(dong)水(shui)(shui)母(mu)(mu)體向(xiang)上(shang)運(yun)(yun)(yun)動(dong)(dong)(dong)，當(dang)傘(san)(san)及(ji)傘(san)(san)緣(yuan)(yuan)(yuan)肌(ji)肉(rou)(rou)舒張，被(bei)壓縮(suo)(suo)(suo)(suo)(suo)(suo)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)中膠層的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)彈性，使(shi)(shi)傘(san)(san)又(you)(you)恢復了原(yuan)形(xing)，水(shui)(shui)又(you)(you)重新進入傘(san)(san)緣(yuan)(yuan)(yuan)內，身(shen)體下(xia)沉，但(dan)由(you)(you)于(yu)收(shou)縮(suo)(suo)(suo)(suo)(suo)(suo)比舒張要快(kuai)，所(suo)(suo)以(yi)水(shui)(shui)母(mu)(mu)還是(shi)可(ke)(ke)以(yi)向(xiang)上(shang)垂直運(yun)(yun)(yun)動(dong)(dong)(dong)。水(shui)(shui)母(mu)(mu)類(lei)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)垂直運(yun)(yun)(yun)動(dong)(dong)(dong)在有(you)(you)(you)緣(yuan)(yuan)(yuan)膜的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)水(shui)(shui)母(mu)(mu)可(ke)(ke)以(yi)看(kan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)更(geng)為清楚。一(yi)旦肌(ji)肉(rou)(rou)停止(zhi)收(shou)縮(suo)(suo)(suo)(suo)(suo)(suo)，水(shui)(shui)母(mu)(mu)就會(hui)自(zi)然下(xia)沉。其(qi)水(shui)(shui)平(ping)方向(xiang)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)運(yun)(yun)(yun)動(dong)(dong)(dong)多(duo)是(shi)被(bei)動(dong)(dong)(dong)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)，多(duo)是(shi)由(you)(you)于(yu)水(shui)(shui)流及(ji)風力(li)所(suo)(suo)推動(dong)(dong)(dong)。又(you)(you)例如(ru)在珊瑚類(lei)，海葵的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)肌(ji)原(yuan)纖維(wei)(wei)(wei)在隔膜上(shang)形(xing)成發達(da)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)牽縮(suo)(suo)(suo)(suo)(suo)(suo)肌(ji)，它的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)收(shou)縮(suo)(suo)(suo)(suo)(suo)(suo)非常(chang)有(you)(you)(you)力(li)，所(suo)(suo)以(yi)當(dang)海葵固(gu)著在巖石上(shang)是(shi)很(hen)難將它取(qu)下(xia)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)。

取食與消化

刺胞(bao)動(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)(wu)都是肉食(shi)(shi)(shi)(shi)(shi)(shi)(shi)性(xing)(xing)的(de)(de)(de)(de)，以(yi)浮游生物(wu)(wu)(wu)(wu)(wu)，小的(de)(de)(de)(de)甲殼(ke)類(lei)、多(duo)(duo)毛(mao)類(lei)甚至小的(de)(de)(de)(de)魚類(lei)為食(shi)(shi)(shi)(shi)(shi)(shi)(shi)。由(you)(you)(you)于(yu)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)(wu)(wu)(wu)的(de)(de)(de)(de)機械刺激(ji)和(he)化學(xue)刺激(ji)，引起(qi)水螅類(lei)動(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)(wu)伸(shen)長觸(chu)手，并(bing)放出刺絲(si)囊以(yi)纏繞、麻痹、毒殺捕獲物(wu)(wu)(wu)(wu)(wu)，再將(jiang)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)(wu)(wu)(wu)送(song)入(ru)口(kou)中。口(kou)區腺細(xi)(xi)(xi)胞(bao)分(fen)泌的(de)(de)(de)(de)粘(zhan)液有(you)(you)(you)利(li)于(yu)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)(wu)(wu)(wu)的(de)(de)(de)(de)吞咽(yan)，食(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)(wu)(wu)(wu)進(jin)(jin)入(ru)胃腔(qiang)后(hou)，胃層的(de)(de)(de)(de)腺細(xi)(xi)(xi)胞(bao)開(kai)始分(fen)泌蛋白(bai)酶(mei)，分(fen)解(jie)、消化食(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)(wu)(wu)(wu)使之(zhi)(zhi)形(xing)成(cheng)許(xu)多(duo)(duo)多(duo)(duo)肽(tai)，同時(shi)在胃腔(qiang)中由(you)(you)(you)于(yu)營(ying)(ying)(ying)養(yang)肌肉細(xi)(xi)(xi)胞(bao)的(de)(de)(de)(de)鞭(bian)毛(mao)運動(dong)(dong)(dong)(dong)，食(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)(wu)(wu)(wu)得以(yi)混合(he)(he)與推動(dong)(dong)(dong)(dong)。經這種(zhong)細(xi)(xi)(xi)胞(bao)外消化之(zhi)(zhi)后(hou)，開(kai)始細(xi)(xi)(xi)胞(bao)內(nei)(nei)的(de)(de)(de)(de)消化過程，營(ying)(ying)(ying)養(yang)肌肉細(xi)(xi)(xi)胞(bao)的(de)(de)(de)(de)偽足吞噬食(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)(wu)(wu)(wu)顆(ke)粒，在細(xi)(xi)(xi)胞(bao)內(nei)(nei)形(xing)成(cheng)大量(liang)的(de)(de)(de)(de)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)(wu)(wu)(wu)泡(pao)，經過酸性(xing)(xing)及(ji)(ji)堿性(xing)(xing)的(de)(de)(de)(de)化學(xue)過程之(zhi)(zhi)后(hou)，營(ying)(ying)(ying)養(yang)物(wu)(wu)(wu)(wu)(wu)質由(you)(you)(you)細(xi)(xi)(xi)胞(bao)的(de)(de)(de)(de)擴散(san)作(zuo)用輸送(song)到全身。缽水母類(lei)及(ji)(ji)珊(shan)瑚(hu)(hu)類(lei)胃腔(qiang)結構比較復雜。缽水母的(de)(de)(de)(de)胃腔(qiang)中有(you)(you)(you)各(ge)種(zhong)輻(fu)管(guan)(guan)及(ji)(ji)環管(guan)(guan)，胃囊中有(you)(you)(you)內(nei)(nei)胚層起(qi)源的(de)(de)(de)(de)胃絲(si)；珊(shan)瑚(hu)(hu)類(lei)的(de)(de)(de)(de)胃腔(qiang)被許(xu)多(duo)(duo)隔(ge)膜分(fen)隔(ge)成(cheng)許(xu)多(duo)(duo)小室(shi)，隔(ge)膜上有(you)(you)(you)隔(ge)膜絲(si)。胃絲(si)及(ji)(ji)隔(ge)膜絲(si)中含有(you)(you)(you)大量(liang)的(de)(de)(de)(de)刺細(xi)(xi)(xi)胞(bao)及(ji)(ji)腺細(xi)(xi)(xi)胞(bao)，它們是將(jiang)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)(wu)(wu)(wu)吞入(ru)胃腔(qiang)之(zhi)(zhi)后(hou)才殺死及(ji)(ji)消化。消化后(hou)的(de)(de)(de)(de)營(ying)(ying)(ying)養(yang)物(wu)(wu)(wu)(wu)(wu)通過各(ge)種(zhong)管(guan)(guan)道輸送(song)到全身，未消化的(de)(de)(de)(de)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)(wu)(wu)(wu)殘(can)渣仍由(you)(you)(you)口(kou)排出。糖(tang)元及(ji)(ji)脂肪是腔(qiang)腸動(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)(wu)的(de)(de)(de)(de)主要貯存物(wu)(wu)(wu)(wu)(wu)。刺胞(bao)動(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)(wu)中許(xu)多(duo)(duo)種(zhong)類(lei)，特(te)別是海洋中的(de)(de)(de)(de)造礁珊(shan)瑚(hu)(hu)類(lei)，體內(nei)(nei)均有(you)(you)(you)共生的(de)(de)(de)(de)藻類(lei)，如動(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)(wu)黃藻、腰鞭(bian)毛(mao)藻之(zhi)(zhi)類(lei)。藻類(lei)能進(jin)(jin)行光合(he)(he)作(zuo)用，產生甘(gan)油、脂肪、糖(tang)及(ji)(ji)脯氨酸等，并(bing)提供給刺胞(bao)動(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)(wu)作(zuo)為其補充營(ying)(ying)(ying)養(yang)。這將(jiang)在珊(shan)瑚(hu)(hu)綱中做進(jin)(jin)一(yi)步的(de)(de)(de)(de)敘(xu)述。

呼吸與排泄

刺(ci)胞(bao)(bao)動物沒有(you)專門(men)的(de)呼吸及(ji)(ji)排(pai)泄(xie)器官，由于身體(ti)是(shi)由兩層細(xi)胞(bao)(bao)圍繞胃循環(huan)(huan)腔(qiang)所組成，并通過口使胃腔(qiang)與(yu)外界相通，實際(ji)上體(ti)壁的(de)兩層細(xi)胞(bao)(bao)均(jun)與(yu)外界環(huan)(huan)境接(jie)觸(chu)，所以呼吸與(yu)排(pai)泄(xie)作用可以由體(ti)壁細(xi)胞(bao)(bao)直接(jie)獨立進行。出、入(ru)口及(ji)(ji)胃腔(qiang)的(de)水流(liu)可以攜帶(dai)入(ru)新(xin)鮮的(de)氧氣，并帶(dai)走代(dai)謝產物。刺(ci)胞(bao)(bao)動物的(de)主要(yao)含氮廢物是(shi)氨。

神經傳導及感官

刺(ci)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)動(dong)(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)是(shi)(shi)(shi)最早出現神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)結(jie)(jie)構(gou)的(de)(de)(de)(de)(de)(de)(de)(de)多(duo)(duo)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)動(dong)(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)。神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)結(jie)(jie)構(gou)原始，是(shi)(shi)(shi)由(you)(you)雙極(ji)(ji)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)、多(duo)(duo)極(ji)(ji)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)及(ji)(ji)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)纖(xian)維(wei)聯合成(cheng)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)叢或(huo)(huo)(huo)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)網(wang)，一(yi)(yi)(yi)(yi)般位(wei)(wei)于外(wai)(wai)表皮(pi)(pi)(pi)(pi)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)基部肌(ji)肉(rou)層(ceng)(ceng)之(zhi)(zhi)外(wai)(wai)，呈網(wang)狀分(fen)布(bu)，故稱網(wang)狀神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)系統(tong)（netnervous system）。由(you)(you)于神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)可(ke)(ke)向(xiang)(xiang)各(ge)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)方向(xiang)(xiang)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)，也(ye)稱為漫散(san)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)系統(tong)（diffusenervous system）。水(shui)(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)就(jiu)(jiu)(jiu)只(zhi)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)網(wang)，但大(da)多(duo)(duo)數(shu)腔腸(chang)(chang)(chang)(chang)動(dong)(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)除了表皮(pi)(pi)(pi)(pi)的(de)(de)(de)(de)(de)(de)(de)(de)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)網(wang)之(zhi)(zhi)外(wai)(wai)，在(zai)(zai)(zai)(zai)胃層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)(de)(de)基部也(ye)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)網(wang)，這(zhe)兩(liang)(liang)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)網(wang)或(huo)(huo)(huo)是(shi)(shi)(shi)完全獨立(li)的(de)(de)(de)(de)(de)(de)(de)(de)，或(huo)(huo)(huo)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)纖(xian)維(wei)相聯。1971年Westfall等(deng)首先證(zheng)明(ming)了水(shui)(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)及(ji)(ji)其(qi)他(ta)腔腸(chang)(chang)(chang)(chang)動(dong)(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)在(zai)(zai)(zai)(zai)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)之(zhi)(zhi)間、神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)與效應(ying)器(qi)(qi)（表皮(pi)(pi)(pi)(pi)肌(ji)肉(rou)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)、刺(ci)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)、腺細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)等(deng)）之(zhi)(zhi)間也(ye)存(cun)在(zai)(zai)(zai)(zai)著突(tu)觸(chu)(chu)傳(chuan)(chuan)(chuan)(chuan)遞（synaptic transmission）。即神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)沖(chong)(chong)動(dong)(dong)(dong)(dong)(dong)的(de)(de)(de)(de)(de)(de)(de)(de)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)是(shi)(shi)(shi)由(you)(you)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)軸突(tu)，傳(chuan)(chuan)(chuan)(chuan)遞給另(ling)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)樹(shu)突(tu)。軸突(tu)的(de)(de)(de)(de)(de)(de)(de)(de)末(mo)(mo)端(duan)具有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)突(tu)觸(chu)(chu)小(xiao)泡（synaptic vesicle），樹(shu)突(tu)的(de)(de)(de)(de)(de)(de)(de)(de)末(mo)(mo)端(duan)沒有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)。傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)時(shi)，突(tu)觸(chu)(chu)小(xiao)泡釋放乙(yi)酰膽(dan)堿(jian)引起(qi)(qi)(qi)后(hou)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)興(xing)奮，沖(chong)(chong)動(dong)(dong)(dong)(dong)(dong)傳(chuan)(chuan)(chuan)(chuan)出以后(hou)，乙(yi)酰膽(dan)堿(jian)被神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)末(mo)(mo)稍(shao)表面(mian)的(de)(de)(de)(de)(de)(de)(de)(de)膽(dan)堿(jian)酯酶水(shui)(shui)(shui)(shui)(shui)(shui)(shui)解成(cheng)膽(dan)堿(jian)及(ji)(ji)乙(yi)酸而(er)(er)解除了激(ji)(ji)活作(zuo)用(yong)。以后(hou)又(you)發現腔腸(chang)(chang)(chang)(chang)動(dong)(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)的(de)(de)(de)(de)(de)(de)(de)(de)突(tu)觸(chu)(chu)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)分(fen)為兩(liang)(liang)種(zhong)(zhong)(zhong)類(lei)(lei)型(xing)(xing)(xing)(xing)。一(yi)(yi)(yi)(yi)類(lei)(lei)突(tu)觸(chu)(chu)是(shi)(shi)(shi)對(dui)稱性(xing)(xing)(xing)的(de)(de)(de)(de)(de)(de)(de)(de)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)（symmetrical），即兩(liang)(liang)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)或(huo)(huo)(huo)多(duo)(duo)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)末(mo)(mo)端(duan)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)突(tu)觸(chu)(chu)小(xiao)泡，因此沖(chong)(chong)動(dong)(dong)(dong)(dong)(dong)可(ke)(ke)以同(tong)時(shi)向(xiang)(xiang)兩(liang)(liang)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)或(huo)(huo)(huo)幾(ji)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)方向(xiang)(xiang)傳(chuan)(chuan)(chuan)(chuan)遞，這(zhe)種(zhong)(zhong)(zhong)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)也(ye)叫非(fei)極(ji)(ji)性(xing)(xing)(xing)的(de)(de)(de)(de)(de)(de)(de)(de)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)（nonpolarized transmission）；另(ling)一(yi)(yi)(yi)(yi)類(lei)(lei)突(tu)觸(chu)(chu)是(shi)(shi)(shi)不(bu)對(dui)稱的(de)(de)(de)(de)(de)(de)(de)(de)（asymmetrical），即神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)只(zhi)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)末(mo)(mo)端(duan)具突(tu)觸(chu)(chu)小(xiao)泡，神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)沖(chong)(chong)動(dong)(dong)(dong)(dong)(dong)只(zhi)能(neng)向(xiang)(xiang)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)方向(xiang)(xiang)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)，因此也(ye)稱為有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)極(ji)(ji)性(xing)(xing)(xing)的(de)(de)(de)(de)(de)(de)(de)(de)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)（polarized transmission）。最近的(de)(de)(de)(de)(de)(de)(de)(de)研究(jiu)證(zheng)明(ming)刺(ci)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)動(dong)(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)的(de)(de)(de)(de)(de)(de)(de)(de)非(fei)極(ji)(ji)性(xing)(xing)(xing)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)是(shi)(shi)(shi)很(hen)普遍的(de)(de)(de)(de)(de)(de)(de)(de)。也(ye)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)人認(ren)為刺(ci)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)動(dong)(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)的(de)(de)(de)(de)(de)(de)(de)(de)兩(liang)(liang)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)網(wang)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)是(shi)(shi)(shi)由(you)(you)多(duo)(duo)極(ji)(ji)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)形(xing)成(cheng)的(de)(de)(de)(de)(de)(de)(de)(de)非(fei)極(ji)(ji)性(xing)(xing)(xing)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)，也(ye)就(jiu)(jiu)(jiu)是(shi)(shi)(shi)慢傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)系統(tong)；另(ling)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)是(shi)(shi)(shi)由(you)(you)雙極(ji)(ji)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)形(xing)成(cheng)的(de)(de)(de)(de)(de)(de)(de)(de)極(ji)(ji)性(xing)(xing)(xing)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)，也(ye)就(jiu)(jiu)(jiu)是(shi)(shi)(shi)快傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)系統(tong)。刺(ci)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)動(dong)(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)的(de)(de)(de)(de)(de)(de)(de)(de)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)可(ke)(ke)以有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)2個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)、3個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)或(huo)(huo)(huo)多(duo)(duo)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)長的(de)(de)(de)(de)(de)(de)(de)(de)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)突(tu)起(qi)(qi)(qi)，這(zhe)些(xie)突(tu)起(qi)(qi)(qi)或(huo)(huo)(huo)與感(gan)官(guan)(guan)相聯、或(huo)(huo)(huo)與效應(ying)器(qi)(qi)相聯、或(huo)(huo)(huo)與其(qi)他(ta)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)相聯、或(huo)(huo)(huo)者(zhe)是(shi)(shi)(shi)同(tong)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)同(tong)時(shi)與感(gan)官(guan)(guan)與效應(ying)器(qi)(qi)相聯，這(zhe)種(zhong)(zhong)(zhong)多(duo)(duo)樣性(xing)(xing)(xing)說明(ming)了神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)的(de)(de)(de)(de)(de)(de)(de)(de)原始性(xing)(xing)(xing)。在(zai)(zai)(zai)(zai)生理意(yi)義上(shang)代表了高等(deng)動(dong)(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)所(suo)具有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)的(de)(de)(de)(de)(de)(de)(de)(de)感(gan)覺(jue)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)、運動(dong)(dong)(dong)(dong)(dong)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)及(ji)(ji)中(zhong)(zhong)樞神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)的(de)(de)(de)(de)(de)(de)(de)(de)起(qi)(qi)(qi)始階(jie)段。此外(wai)(wai)，刺(ci)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)動(dong)(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)的(de)(de)(de)(de)(de)(de)(de)(de)非(fei)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)，即上(shang)皮(pi)(pi)(pi)(pi)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)也(ye)是(shi)(shi)(shi)很(hen)常見的(de)(de)(de)(de)(de)(de)(de)(de)，例如刺(ci)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)、表皮(pi)(pi)(pi)(pi)肌(ji)肉(rou)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)可(ke)(ke)以完全獨立(li)于神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)而(er)(er)被自身(shen)(shen)(shen)所(suo)控(kong)制。水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母型(xing)(xing)(xing)(xing)的(de)(de)(de)(de)(de)(de)(de)(de)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)結(jie)(jie)構(gou)比(bi)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)型(xing)(xing)(xing)(xing)復雜，例如水(shui)(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母，除了傘(san)(san)部的(de)(de)(de)(de)(de)(de)(de)(de)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)網(wang)之(zhi)(zhi)外(wai)(wai)，傘(san)(san)緣(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)上(shang)皮(pi)(pi)(pi)(pi)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)分(fen)別在(zai)(zai)(zai)(zai)傘(san)(san)緣(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)上(shang)、下(xia)面(mian)集中(zhong)(zhong)形(xing)成(cheng)兩(liang)(liang)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)環。下(xia)面(mian)（或(huo)(huo)(huo)稱外(wai)(wai)面(mian)）的(de)(de)(de)(de)(de)(de)(de)(de)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)環更發達。缽(bo)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母類(lei)(lei)的(de)(de)(de)(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母型(xing)(xing)(xing)(xing)多(duo)(duo)數(shu)沒有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)這(zhe)種(zhong)(zhong)(zhong)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)環，而(er)(er)是(shi)(shi)(shi)在(zai)(zai)(zai)(zai)傘(san)(san)緣(yuan)集中(zhong)(zhong)形(xing)成(cheng)4～8個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)節(jie)(jie)。水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母型(xing)(xing)(xing)(xing)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)體(ti)(ti)(ti)均能(neng)表現出一(yi)(yi)(yi)(yi)種(zhong)(zhong)(zhong)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)節(jie)(jie)奏的(de)(de)(de)(de)(de)(de)(de)(de)收(shou)縮運動(dong)(dong)(dong)(dong)(dong)，這(zhe)是(shi)(shi)(shi)由(you)(you)于水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母的(de)(de)(de)(de)(de)(de)(de)(de)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)結(jie)(jie)構(gou)每隔一(yi)(yi)(yi)(yi)定時(shi)間能(neng)自發地產生動(dong)(dong)(dong)(dong)(dong)作(zuo)電(dian)位(wei)(wei)，并經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)過(guo)(guo)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)傳(chuan)(chuan)(chuan)(chuan)導(dao)(dao)(dao)(dao)引起(qi)(qi)(qi)整個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)身(shen)(shen)(shen)體(ti)(ti)(ti)的(de)(de)(de)(de)(de)(de)(de)(de)收(shou)縮。研究(jiu)已經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)證(zheng)明(ming)這(zhe)種(zhong)(zhong)(zhong)自發的(de)(de)(de)(de)(de)(de)(de)(de)動(dong)(dong)(dong)(dong)(dong)作(zuo)電(dian)位(wei)(wei)是(shi)(shi)(shi)由(you)(you)起(qi)(qi)(qi)博(bo)(bo)(bo)(bo)點(dian)的(de)(de)(de)(de)(de)(de)(de)(de)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)所(suo)引起(qi)(qi)(qi)。起(qi)(qi)(qi)博(bo)(bo)(bo)(bo)點(dian)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)在(zai)(zai)(zai)(zai)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母存(cun)在(zai)(zai)(zai)(zai)于外(wai)(wai)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)環中(zhong)(zhong)，在(zai)(zai)(zai)(zai)缽(bo)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母類(lei)(lei)存(cun)在(zai)(zai)(zai)(zai)于感(gan)官(guan)(guan)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)節(jie)(jie)中(zhong)(zhong)。而(er)(er)且每一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)節(jie)(jie)（一(yi)(yi)(yi)(yi)般4～8個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)）都(dou)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)起(qi)(qi)(qi)博(bo)(bo)(bo)(bo)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)元(yuan)(yuan)，它是(shi)(shi)(shi)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母類(lei)(lei)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)節(jie)(jie)奏博(bo)(bo)(bo)(bo)動(dong)(dong)(dong)(dong)(dong)的(de)(de)(de)(de)(de)(de)(de)(de)中(zhong)(zhong)心。一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母體(ti)(ti)(ti)似乎(hu)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)起(qi)(qi)(qi)博(bo)(bo)(bo)(bo)點(dian)就(jiu)(jiu)(jiu)足以引起(qi)(qi)(qi)身(shen)(shen)(shen)體(ti)(ti)(ti)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)節(jie)(jie)奏的(de)(de)(de)(de)(de)(de)(de)(de)收(shou)縮運動(dong)(dong)(dong)(dong)(dong)，但實驗證(zheng)明(ming)多(duo)(duo)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)起(qi)(qi)(qi)博(bo)(bo)(bo)(bo)點(dian)比(bi)僅有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)起(qi)(qi)(qi)博(bo)(bo)(bo)(bo)點(dian)能(neng)使收(shou)縮的(de)(de)(de)(de)(de)(de)(de)(de)節(jie)(jie)奏更有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)規(gui)律、更有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)保障、使間隔的(de)(de)(de)(de)(de)(de)(de)(de)時(shi)間也(ye)較(jiao)短。腔腸(chang)(chang)(chang)(chang)動(dong)(dong)(dong)(dong)(dong)物(wu)(wu)(wu)(wu)的(de)(de)(de)(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)型(xing)(xing)(xing)(xing)體(ti)(ti)(ti)沒有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)明(ming)顯(xian)的(de)(de)(de)(de)(de)(de)(de)(de)感(gan)官(guan)(guan)，其(qi)感(gan)覺(jue)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)可(ke)(ke)分(fen)布(bu)全身(shen)(shen)(shen)，但觸(chu)(chu)手、口區(qu)較(jiao)為豐富。水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母型(xing)(xing)(xing)(xing)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)體(ti)(ti)(ti)，在(zai)(zai)(zai)(zai)傘(san)(san)緣(yuan)具有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)豐富的(de)(de)(de)(de)(de)(de)(de)(de)感(gan)覺(jue)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)或(huo)(huo)(huo)感(gan)覺(jue)器(qi)(qi)官(guan)(guan)。感(gan)覺(jue)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)的(de)(de)(de)(de)(de)(de)(de)(de)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)體(ti)(ti)(ti)都(dou)是(shi)(shi)(shi)具纖(xian)毛(mao)的(de)(de)(de)(de)(de)(de)(de)(de)。感(gan)覺(jue)器(qi)(qi)官(guan)(guan)包(bao)括(kuo)眼(yan)點(dian)及(ji)(ji)平(ping)(ping)衡(heng)囊(nang)(nang)(nang)。眼(yan)點(dian)是(shi)(shi)(shi)由(you)(you)感(gan)覺(jue)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)構(gou)成(cheng)的(de)(de)(de)(de)(de)(de)(de)(de)杯狀物(wu)(wu)(wu)(wu)，內有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)色素顆(ke)粒分(fen)布(bu)，它對(dui)光(guang)(guang)線或(huo)(huo)(huo)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)正趨性(xing)(xing)(xing)，即有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)光(guang)(guang)時(shi)游向(xiang)(xiang)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)面(mian)。或(huo)(huo)(huo)對(dui)光(guang)(guang)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)負趨性(xing)(xing)(xing)，即有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)光(guang)(guang)時(shi)下(xia)沉(chen)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)底，無光(guang)(guang)或(huo)(huo)(huo)弱(ruo)光(guang)(guang)時(shi)浮(fu)向(xiang)(xiang)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)面(mian)。平(ping)(ping)衡(heng)囊(nang)(nang)(nang)在(zai)(zai)(zai)(zai)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母結(jie)(jie)構(gou)簡單(dan)，在(zai)(zai)(zai)(zai)緣(yuan)膜基部或(huo)(huo)(huo)下(xia)傘(san)(san)面(mian)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)環（即外(wai)(wai)神(shen)(shen)(shen)(shen)(shen)(shen)(shen)(shen)經(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)(jing)環）處形(xing)成(cheng)一(yi)(yi)(yi)(yi)個(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)小(xiao)囊(nang)(nang)(nang)，囊(nang)(nang)(nang)的(de)(de)(de)(de)(de)(de)(de)(de)內壁有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)感(gan)覺(jue)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)，細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)上(shang)也(ye)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)纖(xian)毛(mao)。囊(nang)(nang)(nang)的(de)(de)(de)(de)(de)(de)(de)(de)底部有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)一(yi)(yi)(yi)(yi)鈣質結(jie)(jie)石。它是(shi)(shi)(shi)一(yi)(yi)(yi)(yi)種(zhong)(zhong)(zhong)重力感(gan)受器(qi)(qi)。當傘(san)(san)緣(yuan)傾斜時(shi)，結(jie)(jie)石與感(gan)覺(jue)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)的(de)(de)(de)(de)(de)(de)(de)(de)纖(xian)毛(mao)接觸(chu)(chu)，并刺(ci)激(ji)(ji)纖(xian)毛(mao)細(xi)(xi)(xi)胞(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)(bao)以產生動(dong)(dong)(dong)(dong)(dong)作(zuo)電(dian)位(wei)(wei)，抑制了該側(ce)肌(ji)肉(rou)纖(xian)維(wei)的(de)(de)(de)(de)(de)(de)(de)(de)收(shou)縮，通過(guo)(guo)肌(ji)肉(rou)收(shou)縮再調整身(shen)(shen)(shen)體(ti)(ti)(ti)使恢復平(ping)(ping)衡(heng)位(wei)(wei)置。缽(bo)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)母類(lei)(lei)的(de)(de)(de)(de)(de)(de)(de)(de)平(ping)(ping)衡(heng)囊(nang)(nang)(nang)結(jie)(jie)構(gou)更復雜，將在(zai)(zai)(zai)(zai)有(you)(you)(you)(you)(you)(you)(you)(you)(you)(you)關節(jie)(jie)中(zhong)(zhong)敘述(shu)

生殖與生活史

無(wu)性生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)及(ji)有(you)性生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)在(zai)腔(qiang)(qiang)腸(chang)動物中(zhong)都是很(hen)普遍的(de)(de)(de)(de)(de)。無(wu)性生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)的(de)(de)(de)(de)(de)主要(yao)形(xing)(xing)(xing)(xing)式是出(chu)(chu)芽(ya)(ya)生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)，特別是在(zai)水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)型(xing)(xing)更為(wei)常見。例(li)(li)如水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)出(chu)(chu)芽(ya)(ya)時(shi)從身(shen)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)的(de)(de)(de)(de)(de)靠(kao)基部通(tong)過體(ti)(ti)(ti)(ti)(ti)(ti)(ti)壁(bi)及(ji)胃(wei)腔(qiang)(qiang)的(de)(de)(de)(de)(de)向外突出(chu)(chu)，再(zai)(zai)長出(chu)(chu)觸手與(yu)(yu)(yu)口即形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)芽(ya)(ya)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)，以后(hou)(hou)芽(ya)(ya)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)與(yu)(yu)(yu)母(mu)(mu)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)分(fen)離即形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)新(xin)的(de)(de)(de)(de)(de)個體(ti)(ti)(ti)(ti)(ti)(ti)(ti)。但在(zai)藪枝螅(xi)(xi)（Obelia）所(suo)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)的(de)(de)(de)(de)(de)芽(ya)(ya)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)與(yu)(yu)(yu)母(mu)(mu)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)不分(fen)離則形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)了(le)群(qun)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)。其次，也(ye)(ye)可(ke)以通(tong)過分(fen)裂(lie)方式進(jin)(jin)行無(wu)性生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)，主要(yao)發(fa)生(sheng)(sheng)(sheng)(sheng)在(zai)水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)型(xing)(xing)，例(li)(li)如海葵可(ke)以縱分(fen)裂(lie)，缽水(shui)(shui)(shui)(shui)(shui)(shui)母(mu)(mu)的(de)(de)(de)(de)(de)幼體(ti)(ti)(ti)(ti)(ti)(ti)(ti)以橫(heng)分(fen)裂(lie)進(jin)(jin)行無(wu)性生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)。此外水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)型(xing)(xing)一(yi)(yi)(yi)般(ban)具有(you)很(hen)強的(de)(de)(de)(de)(de)再(zai)(zai)生(sheng)(sheng)(sheng)(sheng)能力，例(li)(li)如，將水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)切成(cheng)(cheng)(cheng)(cheng)數段，條件合宜時(shi)每段都可(ke)以再(zai)(zai)生(sheng)(sheng)(sheng)(sheng)成(cheng)(cheng)(cheng)(cheng)一(yi)(yi)(yi)個新(xin)的(de)(de)(de)(de)(de)個體(ti)(ti)(ti)(ti)(ti)(ti)(ti)，再(zai)(zai)生(sheng)(sheng)(sheng)(sheng)時(shi)口與(yu)(yu)(yu)反(fan)口端(duan)的(de)(de)(de)(de)(de)極性不變，但口端(duan)的(de)(de)(de)(de)(de)再(zai)(zai)生(sheng)(sheng)(sheng)(sheng)速(su)度比(bi)反(fan)口端(duan)迅速(su)。所(suo)以水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)型(xing)(xing)的(de)(de)(de)(de)(de)再(zai)(zai)生(sheng)(sheng)(sheng)(sheng)現象(xiang)也(ye)(ye)被認為(wei)是無(wu)性生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)的(de)(de)(de)(de)(de)一(yi)(yi)(yi)種方式。有(you)些(xie)生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)出(chu)(chu)現在(zai)多數水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)型(xing)(xing)及(ji)所(suo)有(you)的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)(shui)(shui)母(mu)(mu)型(xing)(xing)，除(chu)少數種類例(li)(li)如水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)為(wei)雌雄(xiong)同體(ti)(ti)(ti)(ti)(ti)(ti)(ti)之外，絕大多數種類為(wei)雌雄(xiong)異(yi)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)（或(huo)異(yi)群(qun)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)）。生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)細(xi)胞(bao)(bao)來源于間(jian)細(xi)胞(bao)(bao)，然后(hou)(hou)遷移到固(gu)定的(de)(de)(de)(de)(de)位(wei)置上(shang)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)腺。水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)蟲綱的(de)(de)(de)(de)(de)動物生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)腺來源于表皮(pi)(pi)(pi)層(ceng)(ceng)，例(li)(li)如水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)，水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)水(shui)(shui)(shui)(shui)(shui)(shui)母(mu)(mu)的(de)(de)(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)腺位(wei)于放射(she)管下(xia)或(huo)垂唇周圍(wei)，但都是來源于表皮(pi)(pi)(pi)層(ceng)(ceng)細(xi)胞(bao)(bao)。缽水(shui)(shui)(shui)(shui)(shui)(shui)母(mu)(mu)綱的(de)(de)(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)細(xi)胞(bao)(bao)起(qi)源于胃(wei)層(ceng)(ceng)位(wei)于胃(wei)囊低部。珊瑚綱的(de)(de)(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)細(xi)胞(bao)(bao)是由(you)(you)胃(wei)腔(qiang)(qiang)中(zhong)的(de)(de)(de)(de)(de)隔膜上(shang)發(fa)生(sheng)(sheng)(sheng)(sheng)，也(ye)(ye)是內(nei)(nei)(nei)胚(pei)層(ceng)(ceng)來源。腔(qiang)(qiang)腸(chang)動物只有(you)生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)腺，沒(mei)有(you)出(chu)(chu)現生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)導管及(ji)生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)附屬(shu)腺，生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)細(xi)胞(bao)(bao)成(cheng)(cheng)(cheng)(cheng)熟(shu)之后(hou)(hou)由(you)(you)口排出(chu)(chu)，或(huo)由(you)(you)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)壁(bi)破裂(lie)而(er)釋放。受精(jing)(jing)作用依(yi)不同的(de)(de)(de)(de)(de)種而(er)異(yi)，或(huo)在(zai)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)外海水(shui)(shui)(shui)(shui)(shui)(shui)中(zhong)進(jin)(jin)行，或(huo)在(zai)垂管的(de)(de)(de)(de)(de)表面，或(huo)在(zai)胃(wei)腔(qiang)(qiang)內(nei)(nei)(nei)生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)腺的(de)(de)(de)(de)(de)部位(wei)進(jin)(jin)行。卵(luan)裂(lie)是完全的(de)(de)(de)(de)(de)，形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)中(zhong)空的(de)(de)(de)(de)(de)囊胚(pei)，經移入法(fa)或(huo)內(nei)(nei)(nei)陷(xian)法(fa)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)原(yuan)腸(chang)胚(pei)，結果形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)兩層(ceng)(ceng)細(xi)胞(bao)(bao)，即兩個胚(pei)層(ceng)(ceng)，內(nei)(nei)(nei)部成(cheng)(cheng)(cheng)(cheng)團的(de)(de)(de)(de)(de)細(xi)胞(bao)(bao)為(wei)內(nei)(nei)(nei)胚(pei)層(ceng)(ceng)，將來形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)成(cheng)(cheng)(cheng)(cheng)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)的(de)(de)(de)(de)(de)胃(wei)層(ceng)(ceng)，外表的(de)(de)(de)(de)(de)一(yi)(yi)(yi)層(ceng)(ceng)為(wei)外胚(pei)層(ceng)(ceng)，將來形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)成(cheng)(cheng)(cheng)(cheng)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)的(de)(de)(de)(de)(de)表皮(pi)(pi)(pi)層(ceng)(ceng)。實心的(de)(de)(de)(de)(de)原(yuan)腸(chang)胚(pei)迅速(su)延長，體(ti)(ti)(ti)(ti)(ti)(ti)(ti)表出(chu)(chu)現纖毛，形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)了(le)自(zi)由(you)(you)游泳(yong)的(de)(de)(de)(de)(de)浮浪(lang)幼蟲（planula）。浮浪(lang)幼蟲早(zao)期沒(mei)有(you)口及(ji)胃(wei)腔(qiang)(qiang)，游泳(yong)一(yi)(yi)(yi)段時(shi)間(jian)之后(hou)(hou)，固(gu)著在(zai)水(shui)(shui)(shui)(shui)(shui)(shui)草、巖石或(huo)其他物體(ti)(ti)(ti)(ti)(ti)(ti)(ti)上(shang)發(fa)育(yu)成(cheng)(cheng)(cheng)(cheng)水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)型(xing)(xing)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)，或(huo)再(zai)(zai)經過出(chu)(chu)芽(ya)(ya)生(sheng)(sheng)(sheng)(sheng)殖(zhi)(zhi)(zhi)(zhi)(zhi)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)群(qun)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)。淡水(shui)(shui)(shui)(shui)(shui)(shui)生(sheng)(sheng)(sheng)(sheng)活的(de)(de)(de)(de)(de)水(shui)(shui)(shui)(shui)(shui)(shui)螅(xi)(xi)沒(mei)有(you)幼蟲期，其受精(jing)(jing)卵(luan)直接發(fa)育(yu)。