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基本介紹

苔(tai)(tai)蘚(xian)蟲(chong)(Bryozoa=Polyzoa)是固著生(sheng)活的(de)群(qun)體(ti)(ti)(ti)(ti)動物(wu)。苔(tai)(tai)蘚(xian)蟲(chong)是一(yi)種像(xiang)苔(tai)(tai)蘚(xian)植(zhi)物(wu)的(de)動物(wu),外(wai)(wai)形很(hen)像(xiang)植(zhi)物(wu)，但具一(yi)套(tao)完整的(de)消化器，包括口(kou)、食(shi)道(dao)、胃、腸和(he)(he)肛門等。所以把它放(fang)在(zai)動物(wu)界內(nei)。這種生(sheng)物(wu)常(chang)和(he)(he)海(hai)藻伴生(sheng)在(zai)一(yi)起(qi)。個體(ti)(ti)(ti)(ti)小(xiao)，不分節，具體(ti)(ti)(ti)(ti)腔(qiang)。體(ti)(ti)(ti)(ti)外(wai)(wai)分泌(mi)一(yi)層膠質(zhi)，形成群(qun)體(ti)(ti)(ti)(ti)的(de)骨胳。蟲(chong)體(ti)(ti)(ti)(ti)前端(duan)有口(kou)，口(kou)的(de)周圍(wei)有一(yi)冠狀物(wu)，稱“總擔”，其上(shang)(shang)生(sheng)許多觸手。消化道(dao)U字形，口(kou)和(he)(he)肛門因而靠(kao)近。無排泄和(he)(he)循(xun)環器官。海(hai)水、淡水均產。在(zai)地質(zhi)時代(dai)種類很(hen)多，奧陶紀即(ji)已出現，現代(dai)尚有生(sheng)存。例如羽苔(tai)(tai)蟲(chong)附著湖邊石(shi)上(shang)(shang)或植(zhi)物(wu)上(shang)(shang)；牡丹苔(tai)(tai)蘚(xian)蟲(chong)，附著淺(qian)海(hai)巖礁上(shang)(shang)。

常見種類

變口目苔蘚蟲

硬體(ti)為鈣質，蟲管(guan)細長，斷面呈圓(yuan)形(xing)、多邊形(xing)，有間隙(xi)孔、刺(ci)孔、中心(xin)區(內帶)、邊緣區(外帶)，內外帶界線不清，內帶壁厚(hou)，橫板少，外帶壁薄，橫板多。蟲管(guan)壁具平行片狀結構(gou)圍繞蟲室。

隱口目苔蘚蟲

硬體(ti)為鈣質，群(qun)體(ti)呈(cheng)扇狀、漏斗狀、枝(zhi)狀等，通常(chang)由許(xu)多平行(xing)的(de)分枝(zhi)構(gou)成，有橫枝(zhi)相(xiang)連(lian)，構(gou)成網格狀，兩枝(zhi)上有兩列蟲(chong)(chong)室(shi)，蟲(chong)(chong)室(shi)中(zhong)間(jian)被(bei)一中(zhong)棱隔(ge)開(kai)。蟲(chong)(chong)室(shi)呈(cheng)長方(fang)形(xing)(xing)、正方(fang)形(xing)(xing)或六邊形(xing)(xing)，內(nei)外帶(dai)清楚，內(nei)帶(dai)窄，外帶(dai)寬，有刺(ci)孔。單(dan)偏光鏡(jing)下呈(cheng)深棕色，壁具(ju)平行(xing)片(pian)狀結構(gou)。苔蘚(xian)蟲(chong)(chong)以(yi)其群(qun)體(ti)較小，蟲(chong)(chong)管細長與珊(shan)瑚區(qu)別，并以(yi)其蟲(chong)(chong)管向外不收縮，而管壁在加厚(hou)處呈(cheng)疊錐似(si)的(de)平行(xing)片(pian)狀結構(gou)，有間(jian)隙(xi)孔及(ji)刺(ci)孔來區(qu)別珊(shan)瑚藻和珊(shan)瑚。絕大(da)多數苔蘚(xian)蟲(chong)(chong)生活在淺海中(zhong)，也有少數于淡水中(zhong)。

生長與分布

苔(tai)蘚(xian)蟲多生活在海(hai)洋。有菊皿苔(tai)蟲、白(bai)薄苔(tai)蟲和鞭須苔(tai)蟲，我國海(hai)產苔(tai)蘚(xian)蟲分(fen)布在膠州(zhou)灣、浙江淺(qian)海(hai)海(hai)底，和珊瑚(hu)混生在一起(qi)。淡(dan)水產的苔(tai)蘚(xian)蟲在蘇州(zhou)、南(nan)京、深圳淡(dan)水水體中均有。

苔蘚蟲(chong)(chong)(chong)(chong)喜歡(huan)在(zai)(zai)較清潔、富含(han)藻類、溶解氧充足的(de)水(shui)(shui)體(ti)中生(sheng)(sheng)(sheng)活(huo)，能適應各(ge)地(di)(di)帶的(de)溫度，廣(guang)泛分布于(yu)世界(jie)各(ge)地(di)(di)。淡水(shui)(shui)種(zhong)在(zai)(zai)春、秋(qiu)季節（25～28℃）生(sheng)(sheng)(sheng)長旺盛，水(shui)(shui)面有(you)(you)很多上(shang)一年的(de)休(xiu)眠芽，遇(yu)適宜環(huan)境發育成苔蘚蟲(chong)(chong)(chong)(chong)。微污染的(de)水(shui)(shui)體(ti)中也有(you)(you)苔蘚蟲(chong)(chong)(chong)(chong)。在(zai)(zai)微污染源水(shui)(shui)生(sheng)(sheng)(sheng)物預處理過程(cheng)中如有(you)(you)大量(liang)苔蘚蟲(chong)(chong)(chong)(chong)出現(xian)，會被(bei)填(tian)料攔(lan)截，附在(zai)(zai)填(tian)料上(shang)生(sheng)(sheng)(sheng)長，和鐘(zhong)蟲(chong)(chong)(chong)(chong)、聚縮蟲(chong)(chong)(chong)(chong)、獨縮蟲(chong)(chong)(chong)(chong)、累枝(zhi)蟲(chong)(chong)(chong)(chong)、蓋纖蟲(chong)(chong)(chong)(chong)等有(you)(you)粘(zhan)性尾柄的(de)原生(sheng)(sheng)(sheng)動物聚在(zai)(zai)一起，具有(you)(you)一定的(de)生(sheng)(sheng)(sheng)物吸附作(zuo)用(yong)，并吞食水(shui)(shui)中微型(xing)生(sheng)(sheng)(sheng)物和有(you)(you)機(ji)雜(za)質，對水(shui)(shui)體(ti)的(de)凈化有(you)(you)一定積(ji)極(ji)作(zuo)用(yong)。但如果極(ji)度大量(liang)繁(fan)殖，會降低水(shui)(shui)流速(su)度，給工程(cheng)運(yun)行(xing)造成一定不利影響。