毛嵌线螺的研究Ⅰ.繁殖及幼虫发生特征

Study on the Cymatium pileare Ⅰ. Reproduction and larval development characteristics

毛嵌线螺（ Ｃｙｍａｔｉｕｍ ｐｉｌｅａｒｅ）的繁殖过程包括交配、产卵、孵育及幼虫从卵囊中游出等４个阶段．交配一般在产卵前１０～１５ｄ进行，产卵后母体并不离开卵群，而是持续静伏在卵群的开口上进行孵育，直至其中的幼虫离开卵囊．温度和盐度对毛嵌线螺受精卵的发育有重要影响，在２２～３０℃的适宜温度区域内，将受精卵孵育成能自由生活的晚期面盘幼虫需４３８日度左右的总积温．毛嵌线螺受精卵的发育与其他前鳃类腹足动物相似，包括卵裂、囊胚期、原肠期及面盘幼虫期４个阶段．

The breeding cycle of Cymatium Pileare can be separated into the following 4 stages: (1)pairing and copulation; (2)egg laying; (3) incubation and (4) larva departing from the spent egg capsules. The copulation usually takes place 10~15 d before egg laying, and the egg laying season is from March to October when the water temperature is up to 22℃ in Sanya, Hainan Province. After egg laying, the mother C. pileare will remain on the Opening of the egg mass for incubation, which is essential for the fertilized eggs to develop. Temperature and salinity also play important roles in the development of fertilized eggs. At the favorable temperature of 22~30℃ and under the incubation of the mother C. pilaere, the fertilized eggs need about 438 d degree centigrade of accumulating heat to develop into metamorphosed veliger larvae. The process of its larval development is similiar to that of the other prosobranch gastropod, which includes: cleavage, blastula, archenteron and veliger larva stage.