The larval stages of benizuwai-gani, Chinoecetes japonicus Rathbun reared in the laboratory

Abstract

This study deals with the larval stages of C. japonicus, and with the comparison with those of Zuwaigani, C. opilio. There are 2 zoneae and 1 megalopa. The larval stages of C. japonicus are morphologically similar to those of C. opilio excepting some characters as follows: (1) Chromatophores of Zoeae and megalopa are vermillion or crimson in C. japonicus and brown or reddish in C. opilio. (2) C. japonicus is generally bigger than C. opilio in zoeae and megalopa. (3) Length of postero-lateral spine on 3rd abdominal segment is>1.3times the length of the 4th abdominal segment in C. japonicus, but is shorter than (rarely equal to) that in C. opilio. (4) Ischiopodite of cheliped has no spine in C. japonicus, but it has a spine in C. opilio, in megalopa.