542 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



shell ; but the right chela of the male is often more 

 massive than that of the female. The male always shows 

 much greater readiness to emerge from its shell than the 

 female, especially if she be " berried." The pleopods of 

 the female are four in number; they are on the left side 

 only on segments two to five. . The male has three 

 pleopods, that of the second segment being absent, and 

 they are all much smaller than the first three of the 

 female. The fourth pleopod of the female is as much 

 reduced as those of the male. 



Male ^System. 



The Testes (figs. 25 and 40) are paired and 

 quite separate. They lie in or about the third 

 segment of the abdomen, and the vasa deferentia 

 open by a circular hole on the base of the 

 last pair of pereiopods. Both organs are placed in 

 the cleft between the two lobes of the digestive gland, the 

 left on the dorsal side and the right against the muscles. 

 Owing to the twist of the liver, the left testis has become 

 topographically dextral to the right one. Both testes are 

 flat, lozenge-shaped organs, and the superficial left one is 

 slightly larger than the right, which is imbedded in the 

 digestive gland in a laterally erect position. The vasa 

 deferentia are large, prominent yellow tubes in the 

 breeding season. They pursue a tortuous course till they 

 reach the thorax, when they abruptly plunge downwards 

 to the external opening. 



Each testis is essentially a long and excessively 

 convoluted tube, in the length of which the sperms may 

 be seen in every stage from their origin as spermato- 

 blasts to their final condition in their chitinous case. 

 The greater part of the testis — the testis proper — is a 

 narrow lobulated tube, which has become so intensely 

 convoluted and involved that it has the appearance of a 



