【摘要】 本文通过对多齿围沙蚕个体发育的观察,就多齿围沙蚕个体发育的特点、沙蚕发育类型;幼沙蚕的形态特征以及沙蚕幼体消化道内的油球结构及其生理功能等问题作了叙述和探讨。更多还原

【Abstract】 This article is a report on the ontogenesis of Perinerefs nuntia (Savigny). The adult animals were collected from the Zhoushan prefecture along the East China Sea coast, Artificial fertilization was performed in the laboratory under the temperature ranging from 27℃ to 28℃ in the water. The developmental stages are discribed as ollows:Time after fertilization Stages and its characteristics or hatching1hr. 50min. Two-cell stages2hr. 20min. Four-cell stage2hr. 50min, Eight-cell stage3hr, 30min, Sixteen-cell stage6hr. to 20hr. Gastrula stagePost-trochophore: larval is endosed in egg membrane. one pair of anal cirrus; three pairs of rudimentad parapodia; length 0.25mm.45-50hr. Three setiger nectochaete (unhatch): one pair of prostomial tentacle; one pair of parapodia; length 0.30mm,57-70hr. Three setiger nectochaete (hatch): larval continues to deveolp; the parapodia converted into a biramous type; animals are swimming in water and phototropic.12-14hr Three setiger nectochaete: larval showed a negative phototronism and was seen crawling on the bottom.52hr Four setiger nectochaete: length 0.5mm.100hr. Five setiger nectochaete: first pair of parapodia begins to transform into the peristomial cirrus.148hr. Seven setiger nectochaete: three pairs of the peristomial cirrus; length 1.0mm.12-13days. Ten setiger nectochaete: ten pairs of parapodia; four pairs of the peristomial cirrus; one pair of prostomial tentacle; one pair of prostomial palp and one palr of anal cirrus.更多还原