Observations on the embryonic development of some deep-living decapod crustaceans,with particular reference to species of Acanthephyra

Eggs of meso- and bathypelagic decapod crustaceans were removed from gravid females and allowed to develop in vitro. The time course of embryonic development, as indicated by the appearance of certain morphological and physiological features, was determined for most species at a constant temperature of 12°C. The embryonic period, and the time between the appearance of certain key features such as naupliar and compound eyes and heartbeats, showed little variation in any one species. Significant differences were observed in the development times of different species. In general, species with large eggs have a longer embryonic period than those with small eggs, but there also variations between species with eggs of similar size. During the development of Acanthephyra eggs there is an approximate doubling of the egg volume, correlated with a decrease in egg density and an increase in the water content. The increase in the water content and egg volume is similar to that of other decapod eggs. It is concluded that those species with small eggs could have several broods in 1 year, whereas those species with large eggs are likely to be restricted to one, or in some cases possibly two, broods.