238 Phylum Arthropoda 



Lebour (1927 and 1928) was successful in rearing three species of crabs 

 in plunger jars on a diet of the larvae of Ostrea, Teredo, Echinus, and 

 Pomatoceros. The megalopae and young crabs were fed on small pieces 

 of the mantle of Mytilis edulis. The larvae of the native oyster, Ostrea 

 lurida, have been found to be a satisfactory food, as they are held for 

 some time in the mantle cavity of the adult and therefore may be ob- 

 tained in quantity, yet are free-swimming when placed in the water. 

 The veliger larvae of Nudibranchs and the trochophore larvae of the 

 Japanese oyster were also used, but did not prove as satisfactory as 

 those of the native oyster. When the larvae are no longer free- 

 swimming, living food material may be replaced by minced clam muscle, 

 on which the megalopa and young crabs will continue to thrive. It is 

 advisable to provide shells for the glaucothoe and young stages of the 

 Pagurids, and for this purpose the broken off tips of the spirals of 

 Littorina were found suitable. 



The length of time spent in each stage seems to depend considerably 

 on the relative abundance of food, the temperature and salinity of the 

 water, and on other such external conditions. The first zoeal stage, in 

 suitable natural conditions, probably lasts for 2 or 3 days, and the time 

 spent in each stage increases as the larva grows. Under laboratory con- 

 ditions, 4 to 5 weeks is usually required for the development from the 

 egg to the young crab stage. The 6th young crab stage of Hemigrapsus 

 nudus appeared 2 months later. 



These methods have been applied successfully to the rearing of both 

 Brachyura (Hart, 1934) and Anomura. Some slight variations in tech- 

 nique may be found advisable and these will become evident with the 

 development of the experimental work. 



Bibliography 



Brown, E. T. 1898. On keeping medusae alive in an aquarium. J. Mar. Biol. 

 Assoc. 5:176. 



Hart, J. F. L. 1935. The larval development of British Columbia Brachyura. 

 I. Xanthidae, Pinnotheridae (in part) and Grapsidae. Canad. J. Res. 12:411. 



Lebour, M. V. 1926-27. Studies of the Plymouth Brachyura. I. The rearing of 

 crabs in captivity, with a description of the larval stages of Inachus dorsettensis, 

 Macropodia longirostris and Maia squinado. J. Mar. Biol. Assoc, n.s. 14:795. 



1928. The larval stages of the Plymouth Brachyura. Proc. Zool. Soc. Lon- 

 don, pp. 473-560. 



Orton, J. H. 1926-27. On the mode of feeding of the hermit crab, Eupahurus 

 Bernhardus, and some other Decapoda. Ibid. 14:909. 



