Observations on the Embryonic Development of Octopus tetricus (Mollusca : Cephalopoda)

Abstract

The development of O. tetricus embryos reared in the laboratory is described. The course of embryo-genesis is similar to that of O. vulgaris but the shape of stage-time plots differs. Most embryos undergo two reversions during development but failure to reverse does not prevent continued development. Both naturally and artificially hatched embryos still have the internal yolk sac, which is not fully absorbed until 4 or 5 days after hatchnig. Records of egg-laying in the laboratory and of the presence of larvae and juveniles in the wild population indicate that O. tetricus has a prolonged breeding season.