11 



manner. These modifications are shown in the accompanying 

 limire (Plate III). 



While the differences just noted offer the best means of sep- 

 arating the sexes, at certain seasons of the year another differ- 

 ence is present wliieli is made use of by the fishermen. During 

 the breeding season, and for a short time preceding it, the basal 

 segments of the last pair of walking legs takes on a conspicu- 

 ously whitish appearance, due to the enlargement of the terminal 

 portion of the sperm duct. To the fishermen this offers the best 

 means of separating the males from the females, but of course 

 is of value for only a part of the year, while the structure of 

 the swimmerets is available for all except the very young. 

 There are also slight modifications of the filaments of the anten- 

 nae in the males, but as they are inconspicuous it will not be 

 necessary to describe them in detail. 



REPRODUCTIVE ORGANS. 



The internal reproductive organs consist of the glands which 

 develop the sex products and the ducts which carry these prod- 

 ucts to the exterior. These glands occupy corresponding posi- 

 tions in the body sexes and are in general alike in the two sexes 



FEMALE REPRODUCTIVE ORGANS. 



The egg-gland, or ovary, of the female lies in the dorsal part 

 of the body cavity a short distance in front of the posterior end 

 of the carapace. It consists of a central, ring-like portion (com- 

 posed of partly-fused halves), from which finger-like processes 

 are sent off on all sides. The anterior and lateral processes are 

 short and rather small, but the posterior pair are long and slen- 

 der, extending the entire length of the abdomen. In this gland 

 the eggs are formed and matured and are then discharged from 

 the body through a pair of slender oviducts, which open through 

 the basal segments of the last pair of chelate legs. 



MALE REPRODUCTIVE ORGANS. 



The gland of the male, the testis, occupies a similar position. 

 It is. however, a more compact structure and the processes are 

 much shorter than in the ovary, and do not extend far from the 

 central mass. The posterior processes are noticeably much 

 shorter than those of the ovary. The sperm ducts are a pair of 



