牡蛎鳃的发生与研究

ON THE DEVELOPMENT OF GILLS IN THE OYSTER CRASSOSTREA GIGAS

本文详细描述了长牡蛎鳃的发生过程。直线铰合后期,幼虫外套膜两侧各形成一内褶——鳃原基,变态前它们在足的后方相互愈合,将外套腔分为上、下两部分,与此同时,鳃原基横裂出7～8对鳃丝,组成左、右内鳃瓣。在鳃的生长过程中,上、下行鳃丝同时增长,而不是象过去推测的那样,先形成下行鳃丝,顶端折回后再形成上行鳃丝。当稚贝达3～4mm时,左、右外鳃瓣以相同的方式发生。

The development of gills in oyster, Crassostrea gigas (Thumberg), is described. At the straight-hinge stage, the mantle wall produces an elevation on either side of the posterior portion of the body, then these original gills project farther outward. Before metamorphosis, the right and left inner demibranches were mixed with each other behind the foot, dividing the mantle cavity into two parts (inhalant and exhalant chambers). Each demibra-nch bears 7 to 8-paired filaments. Then both filaments of a pair grow simultaneously throughout their length. When spat is about 3mm to 4mm in length, the left and the right outer demibranch develop respectively in the same way as their inner demibranch.