中华虎头蟹幼体发育的初步观察

对中华虎头蟹Orithyiasinica幼体发育过程进行观察。结果表明：幼体发育分为4个主要时期，包括3期潘状幼体和1期大眼幼体。当海水盐度为28，水温为（25．1±0．8）℃时，Ⅰ期潘状幼体历时4～5d发育至Ⅱ期潘状幼体，Ⅱ期溢状幼体历时4～5d发育至Ⅲ期潘状幼体，Ⅲ期潘状幼体历时5—6d发育至大眼幼体，大眼幼体经过5～6d发育至Ⅰ期仔蟹，幼体自然孵化完成全部发育过程共需18—22d。幼体大小、第1和第2颚足外肢羽状刚毛数目、尾叉棘刺数目、腹部肢芽大小是区分各时期潘状幼体的主要形态特征。

Larval development of tiger crab Orithyia sinica

Larval development of tiger crab Orithyia sinica was observed under a light microscope at a water temper- ature of （25.1 ±0.8 ） ℃. It was found that 4 larval stages including 3 zoeal stages and 1 megalop stage were distin- guished by the first stage of juvenile crab. The larvae were hatched as a zoea （Z） which was metamorphosed into the first stage juvenile crab by 4 times of moult, during which Z I larvae developed into Z Ⅱ larvae in 4-5 days, Z Ⅱ larvae developed into Z Ⅲ larvae in 4-5 days, and Z Ⅲ larvae lasted for 5-6 days, then became megalop which molted into juvenile crab 5-6 days later. The whole process of larval development took place during 18-22 d. The developmental stages of the larvae were primarily distinguished by body size, number of hair and spine on the maxilliped and telson, and size of pleopodal buds.