蛋黃水母(mu)(mu)(mu)(學名:Cotylorhiza tuberculata)是(shi)缽水母(mu)(mu)(mu)綱根口水母(mu)(mu)(mu)目的(de)海洋生(sheng)物。還有(you)(you)一(yi)個和希臘神話中的(de)女(nv)妖同名的(de)名字“美(mei)杜莎”(Medusa)。水母(mu)(mu)(mu)體(ti)型較大(da),傘體(ti)直徑一(yi)般35厘米,最大(da)可達50厘米。傘呈圓盤形,由于體(ti)內的(de)生(sheng)殖腺(xian)或其(qi)他胃囊(nang)等(deng)結構具有(you)(you)色澤,而使身體(ti)在透明中出(chu)現中央隆起的(de)金(jin)紅色或桔紅色,看起來是(shi)那么美(mei)味誘人,就(jiu)像剛(gang)煎(jian)煮好的(de)荷(he)包(bao)蛋。
生活史的(de)主(zhu)要(yao)階段是(shi)單(dan)體、水母型(xing)(xing),其水螅(xi)型(xing)(xing)階段不發(fa)達(da)。體型(xing)(xing)較大,沒(mei)有(you)緣膜(mo);胃(wei)循環(huan)腔復雜,輻射管發(fa)達(da),有(you)內胚層起源(yuan)的(de)胃(wei)絲,胃(wei)絲上有(you)刺(ci)細胞;生殖細胞起源(yuan)于內胚層,神經感官較發(fa)達(da),集中形成(cheng)8個(ge)感覺器官。
習海(hai)(hai)(hai)洋生活,水(shui)母(mu)的(de)武器是(shi)魚叉狀(zhuang)觸手,當它們碰(peng)觸到獵物時,就會射(she)出觸手上刺細胞的(de)毒液,獵食(shi)它們的(de)獵物。外形和水(shui)煮蛋很(hen)相似,是(shi)地中(zhong)海(hai)(hai)(hai)最常見(jian)的(de)水(shui)母(mu),也分布于(yu)愛琴海(hai)(hai)(hai)和亞得(de)里亞海(hai)(hai)(hai)。
分布于地中海(hai)、愛(ai)琴海(hai)和亞得里(li)亞海(hai)。地中海(hai)最豐富。
蛋黃(huang)水母體型較大(da),傘(san)(san)(san)(san)體直徑一般35厘米(mi)(mi),最(zui)大(da)可達(da)(da)50厘米(mi)(mi)。傘(san)(san)(san)(san)呈(cheng)圓盤形(xing)(xing),由(you)(you)于體內(nei)的生殖腺或(huo)其(qi)(qi)他胃囊等(deng)結構具有(you)色(se)澤,而(er)使(shi)(shi)身體在透明中(zhong)(zhong)出現(xian)中(zhong)(zhong)央隆(long)起(qi)的金紅(hong)色(se)或(huo)桔紅(hong)色(se),看(kan)起(qi)來是那么美味誘人,就像剛煎(jian)煮好的荷包蛋,傘(san)(san)(san)(san)體的邊緣(yuan)(yuan)厚度通常約17厘米(mi)(mi)。身體區分(fen)成上(shang)傘(san)(san)(san)(san)面(mian)及(ji)下傘(san)(san)(san)(san)面(mian),無緣(yuan)(yuan)膜。傘(san)(san)(san)(san)緣(yuan)(yuan)無觸手,口(kou)(kou)腕(wan)愈合,垂(chui)(chui)唇末端的口(kou)(kou)封閉,而(er)形(xing)(xing)成許多(duo)(duo)新(xin)的細小的吸(xi)口(kou)(kou),早期發育中(zhong)(zhong)具有(you)正常的口(kou)(kou),并有(you)8個(ge)口(kou)(kou)葉,以后(hou)發育中(zhong)(zhong)形(xing)(xing)成8個(ge)口(kou)(kou)腕(wan),口(kou)(kou)腕(wan)再分(fen)枝愈合,原來口(kou)(kou)腕(wan)中(zhong)(zhong)的纖毛溝愈合成小管及(ji)吸(xi)口(kou)(kou)(suctorial mouth)。用(yong)以吸(xi)食,吸(xi)口(kou)(kou)、小管與胃腔(qiang)相連(lian)。一般在垂(chui)(chui)唇、口(kou)(kou)腕(wan)及(ji)傘(san)(san)(san)(san)的外(wai)表(biao)面(mian)分(fen)布有(you)刺細胞。中(zhong)(zhong)膠層很發達(da)(da),也是由(you)(you)蛋白(bai)質及(ji)粘多(duo)(duo)糖形(xing)(xing)成的凝(ning)膠,其(qi)(qi)中(zhong)(zhong)含有(you)膠原纖維。中(zhong)(zhong)膠層也有(you)很大(da)的彈性,由(you)(you)于它(ta)能(neng)維持及(ji)調節離(li)子的成分(fen)及(ji)濃度,而(er)使(shi)(shi)身體在海水中(zhong)(zhong)保(bao)持一定的浮力(li)。肌(ji)肉及(ji)運動(dong)(dong)相似于水螅(xi)水母,圍繞著下傘(san)(san)(san)(san)緣(yuan)(yuan)有(you)由(you)(you)外(wai)胚層形(xing)(xing)成的環(huan)行肌(ji)肉,它(ta)們(men)的收縮造成水母的運動(dong)(dong)。
蛋黃水母的胃(wei)(wei)循環(huan)(huan)(huan)腔(qiang)比水螅水母復雜(za),原始的種類由口經垂唇進(jin)入中(zhong)央的胃(wei)(wei)腔(qiang),胃(wei)(wei)腔(qiang)向(xiang)外延(yan)伸(shen)形(xing)成4個(ge)胃(wei)(wei)囊,胃(wei)(wei)囊之(zhi)間有隔板(ban)(septum),隔板(ban)上有小(xiao)孔,可使胃(wei)(wei)囊之(zhi)間互相溝通以幫助液體的循環(huan)(huan)(huan)流動(dong)(dong)。隔板(ban)上有隔板(ban)肌,內(nei)緣(yuan)有內(nei)胚層(ceng)起源(yuan)的胃(wei)(wei)絲(gastric filaments),共上含有許多刺(ci)細胞及腺細胞,可以固定及殺(sha)死進(jin)入胃(wei)(wei)腔(qiang)的食(shi)物(wu)(wu)。這種胃(wei)(wei)囊及隔板(ban)的結構(gou)僅在幼年階(jie)段(duan)出(chu)現(xian),成年階(jie)段(duan)時形(xing)成了發達(da)的胃(wei)(wei)腔(qiang)及環(huan)(huan)(huan)流管(guan)系統。為(wei)肉食(shi)性動(dong)(dong)物(wu)(wu),以小(xiao)的甲殼(ke)類、浮游生物(wu)(wu)等為(wei)食(shi),實際上也(ye)是一類懸浮取食(shi)者(zhe),以觸手過(guo)濾水中(zhong)的微(wei)小(xiao)的浮游生物(wu)(wu),經口腕溝靠纖(xian)毛作(zuo)用送入口及胃(wei)(wei)腔(qiang),胃(wei)(wei)絲上的刺(ci)細胞殺(sha)死捕獲物(wu)(wu),再由胃(wei)(wei)絲上的腺細胞分泌消化酶(mei)消化食(shi)物(wu)(wu),消化后的營養(yang)物(wu)(wu)靠環(huan)(huan)(huan)流管(guan)壁(bi)的纖(xian)毛擺(bai)動(dong)(dong)以推動(dong)(dong)營養(yang)物(wu)(wu)由胃(wei)(wei)腔(qiang)經從輻(fu)管(guan)進(jin)入環(huan)(huan)(huan)管(guan),再經正輻(fu)管(guan)、間輻(fu)管(guan)、胃(wei)(wei)腔(qiang)及口將未消化吸收的食(shi)物(wu)(wu)殘渣排出(chu)體外。
夏末和(he)初(chu)秋會(hui)聚集(ji)(ji)成(cheng)大集(ji)(ji)團,真正在海灘附近形(xing)成(cheng)危害(hai),對(dui)于人類漁業和(he)船(chuan)只出行都(dou)造成(cheng)很大麻煩。
蛋黃水(shui)母為(wei)雌(ci)雄異體(ti)(ti)(ti)(ti),生(sheng)(sheng)(sheng)殖腺位于胃(wei)襄內,由(you)(you)(you)內胚層(ceng)產生(sheng)(sheng)(sheng)。原始(shi)的種(zhong)類在隔(ge)板兩側共有(you)8個生(sheng)(sheng)(sheng)殖腺。性成(cheng)熟時(shi)常有(you)色澤(ze),易(yi)于識(shi)別。生(sheng)(sheng)(sheng)殖細胞排(pai)到海水(shui)中或口腕處受精,受精卵經(jing)(jing)囊胚期發(fa)育成(cheng)浮(fu)浪幼(you)(you)蟲(chong)(chong),經(jing)(jing)過(guo)一段自由(you)(you)(you)游泳(yong)之后(hou),用其前端固著在物體(ti)(ti)(ti)(ti)上(shang)發(fa)育成(cheng)水(shui)螅型(xing)幼(you)(you)蟲(chong)(chong),稱為(wei)缽口幼(you)(you)蟲(chong)(chong)(scyphistoma),缽口幼(you)(you)蟲(chong)(chong)以(yi)(yi)后(hou)由(you)(you)(you)頂端到基部(bu)進行橫(heng)裂生(sheng)(sheng)(sheng)殖(strobilation),這(zhe)時(shi)稱為(wei)橫(heng)裂體(ti)(ti)(ti)(ti)(strobila),以(yi)(yi)后(hou)橫(heng)裂體(ti)(ti)(ti)(ti)由(you)(you)(you)頂端開始(shi)依次脫離母體(ti)(ti)(ti)(ti)形成(cheng)幼(you)(you)年(nian)的水(shui)母型(xing)體(ti)(ti)(ti)(ti),稱蝶狀(zhuang)幼(you)(you)體(ti)(ti)(ti)(ti)(ephyra),橫(heng)裂體(ti)(ti)(ti)(ti)可以(yi)(yi)生(sheng)(sheng)(sheng)活一到數年(nian),全(quan)部(bu)橫(heng)裂體(ti)(ti)(ti)(ti)脫落(luo)之后(hou),它(ta)又可以(yi)(yi)重新(xin)形成(cheng)缽口幼(you)(you)蟲(chong)(chong),所以(yi)(yi)橫(heng)裂體(ti)(ti)(ti)(ti)是無(wu)性生(sheng)(sheng)(sheng)殖階段。蝶狀(zhuang)幼(you)(you)體(ti)(ti)(ti)(ti)很(hen)小,邊緣(yuan)有(you)很(hen)深的缺刻。它(ta)經(jing)(jing)過(guo)大量的取食(shi)后(hou)發(fa)育成(cheng)水(shui)母型(xing)成(cheng)體(ti)(ti)(ti)(ti)。