Protozoea I of Sicyonia brevirostris Stimpson, ventral view. 



3. Sicyonia dorsalis - Larvae reared to Protozoea I; preserved 

 specimens are now being examined. 



Captive shrimp frequently aborted non- viable eggs which were usu- 

 ally misshapen, discolored, and deposited in clumps. Sometimes a few devel- 

 oped into nauplii or to a point where the nauplius could be seen within the egg. 

 Exanaination of thelycai-/ indicated that the above conditions resulted more from 

 a lack of (or incomplete) fertilization than from incomplete development of the 

 eggs themselves. Of 11 X. kr^yeri which spawned in the laboratory, those re- 

 leasing eggs that failed to develop had retained the implanted spermatophores, 

 whereas those spawning viable eggs had lost all or at least a portion of theirs. 

 As soon as captive shrimp spawn, an examination of each thelcyum might indi- 

 cate which of several individuals spawning simultaneously most likely yielded 

 viable eggs. From the standpoint of minimizing the time spent searching for 

 viable material, such lots of eggs would subsequently receive nnost attention. 



Modifications of methods used in earlier rearing trials have given 

 encouraging results. Attempts to reduce the adverse effects of excessive de- 

 tritus and various micro-organisms had involved the use of sand- filtered and 



1/ Female structure which receives spermatophore (sperm sac) from male. 



15 



