440 



Annals of the Carnegie Museum. 



granulated, almost smooth on proximal parts of outer and inner side, 

 with a small spine near distal end above. Lower side with two rows 

 of spiniform granulations, most distinct in young individuals. Ischi- 

 opodite of the third pair of pereiopods with a strong hook. Copulatory 

 oro;'rn\' (first pair of abdominal appendages) short and straight, with a 

 prominent shoulder on the anterior margin near 

 the tip. Outer and inner part in close apposition 

 to their tips ; outer part ending bluntly, the inner 

 slightly longer and thinner, but also blunt. The 

 inner part carries, at its anterior side, not far from 

 the shoulder, a small, procurved, horny spine. 

 Inner face of inner part flattened, and slightly 

 dilated, with two rows of bristles, which diverge 

 from a low, oblique median rib. 



77ie male of tlie second form differs in the less 



distinctly granulated carapace ; the cheke are 



(^-''■"TT"'^ weaker; thehooksof the third pereiopods smaller; 



J — the copulatory organs are similar, but the horny, 



procurved spine is replaced by a blunt tubercle 



(This gives the whole organ 



P'iG. I. Male copu- 



latory organ of right that is not horny. 



side seen from outside. ^^^^^ ^-^^^^^^ ^j^g ^ 



Fig. 2. Male copula- „ , ^. ., , , ^ , . ^ 



r . i_ J remale: Similar to the male or the second lorin. 



tory organ ot right side 



seen from inside. FiG. Aiiniiliis ventralis \.X2.Xi'&M^.X'S,€iy xh.oxa\yO\di, forming 

 3. Annulus ventralis a simple tuberculiform elevation, with an S-shaped 

 of female. All figures longitudinal fissure, but without any depressions, 

 enlarged twelve diam- Locality : Los Amates, Province of Izabal, Gua- 

 temala. In small streams and swales. January 

 20, 1905; collected by E. B. Williamson, of Bluffton, Ind. (About 

 4 to 5 miles due south of the town of Izabal, south of Rio Malagun.) 



There are 27 specimens in the lot, 13 (^, 14 9- Only one (the 

 largest) is a male of the first form. Most of the specimens are very 

 young. 



The measurements of the largest ^ (I) and 9 ^''^ ^s follows: 



(^ . Total length 51.5 mm., carapace. 25 mm., anterior section of 

 carapace 16.5 mm., areola 8.5 mm., width of areola in the middle 

 0.5 mm., abdomen 26.5 mm., length of hand 20 mm., of palm 11 

 mm., of fingers 9 mm. 



9- Total length 49.5 mm., carapace 24.5 mm., anterior section of 

 carapace 16 mm., areola 8.5 mm., width of areola in the middle 0.5 



