no. 36!3 TWO NEW CRUSTACEANS — BOWMAN AND KORNICKER 3 



copepods were found, suggesting that the life span of the male is 

 much less than that of the female. 



Ostracods that already have laid a clutch of eggs are not attacked. 

 The only parasitized ostracod with its own eggs in its marsupium was 

 a specimen containing copepodids. The susceptible period for the 

 ostracod is the time following its final molt and preceding egg deposi- 

 tion. Once it is in the marsupium, the presence of the copepod 

 inhibits egg laying by its host. Only 1 female Sphaeronellopsis 

 develops in an ostracod, but more than 1 male may be found in a 

 single host. 



Sphaeronellopsis eggs are not laid singly, but in groups, each of 

 which is enclosed by a membrane. All the eggs in 1 ovisac are at the 

 same developmental stage, but those in different ovisacs may be in 

 different stages. We have divided the eggs arbitrarily into 3 cate- 

 gories, according to the stage of development (pi. \d-j; list below) : 

 spherical eggs, pyriform eggs, and copepodids still within the ovisac 

 membrane. Several batches of eggs must be laid at intervals, since 

 ovisacs with all 3 stages may occur together. Each ovisac contains 

 about 15 eggs, and up to 8 ovisacs (about 120 eggs) in one stage have 

 been found in an ostracod. The total number of eggs produced by a 

 female must be at least 3 x 120 or 360, and perhaps more, since it is 

 possible that more than 3 clutches of eggs are laid. 



Data on specimens of Sphaeronellopsis monothrix (the 3 types of 

 ovisacs are shown in pi. Id-f). — 



copepods 



