1917 Fasten: on Decapoda 287 



in their location from those of the Brachyura, being situated in the abdo- 

 men. This is true alike of the hermit as well as of the free-living Ano- 

 mura. The latter, however, show some interesting modifications. 



Let us first consider the male reproductive organs in Lopholithodes 

 mandtii, Haplogaster mortensii and Rhinolithodes tcossnessenskii. All these 

 Anomura belong to the family Lithodidae of the tribe Paguridea and this 

 tribe also includes the true hermit crabs, which comprise the family Pa- 

 guridae. Caiman (1909), in speaking of the testes of the Paguridae, says: 

 "In the Paguridae they are displaced backwards so as to lie wholly in the 

 abdominal region, where they are unsymmetrically placed on the left side, 

 either fused into a single mass or entirely separated from each other, the 

 right testis lying in front of the left." In many respects the testes of the 

 Lithodidae under consideration resemble those of the Paguridae. 



In Lopholithodes mandtii (Fig. 5) there is a pair of testes (Fig. 5, r. t. 

 and I. t.) located slightly above the middle of the abdominal cavity well 

 towards the left side. The left testis (Fig. 5, I. t.) lies lower down in 

 the abdominal cavity than the right one (Fig. 5, r. t.). From each testis 

 a stout vas deferent tube (Fig 5, r. v. d. and I. v. d.) makes its way up- 

 ward to the hidden fifth thoracic leg on its respective side (Fig. 5, f. I.), 

 and after traversing both the coxopodite and the basipodite, it then opens 

 to the exterior through a small pore (Fig. 5, r. o. and I. o.). A closer 

 examination of each testis shows that it is profusely tubular, seeming to 

 be composed of a single slender tube which has become greatly convo- 

 luted and massed. Each testis is distinct and possesses a main lower 

 portion with a thin upwardly projecting part (See Fig. 5, r. t. and I. t.), 

 which runs along the outer wall of its vas deferens. 



The male reproductive organs of Haplogaster mortensii and Rhinoli- 

 thodes tcossnessenskii resemble each other very closely. Here, while the 

 parts of these organs show the same asymmetry as the abdomen, yet there 

 is more symmetry displayed in the internal arrangement of their various 

 portions than in Lopholithodes mandtii or in the Paguridae. The descrip- 

 tion for Haplogaster mortensii will also suffice for Rhinolithodes tvoss- 

 nessenshii. In Haplogaster mortensii there is a pair of tubular testes (Fig. 

 7, r. t. and I. t.) each of which is V-shaped and located on opposite sides 

 of the intestine (Fig. 7, int.) in the middle of the abdominal region. From 

 each testis a vas deferens (Fig. 7, r. v. d. and I. v. d) makes its way up- 

 ward to the base of the degenerate fifth leg (Fig. 7, /. /.) on its respective 

 side, where it opens to the outside. 



Petrolisthes eriomerus is an Anomuran belonging to the tribe Galathei- 

 dae. This tribe is distinguished from the Paguridea by having its parts 



