180 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. [1885. 



The pleopods are nearly as in A.? tridens, but the sexual appendage 

 of the first pair in the male is smaller, much narrower, and apparently 



not fully developed, the specimen probably being immature. The 

 sterna of the four anterior somites of the pleon are each armed with a 

 laterally compressed median tooth, which is very prominent on the 

 first and diminishes in size successively on the succeeding somites. 



Meanuremenis in mUlimeters. 



Sex ^ 



Length from tip of rostrum to tip of telson 110 



Length of carapax including rostrum .56 



Length of rostrum 31.3 



Height of carnax 12.0 



Breadth of carapax ^ 10.5 



Length of eye-stalk and eye 5. G 



Greatesf diameter of eye 4. 



Length of antennal scale 15. 



Bread til ol antennal scale * 6.3 



Length of second gnathopod 33 



Length of first perteopod 27 



Length of chela 6.6 



Breadth of chela 1.3 



Length of dactylus 3. 7 



Length of second peraeopod 35 



Length of chela 7.5 



Breadth of chela 1.2 



Length of dacrylua 4. 5 



Length of third peraeopod 41 



Length of merus 13.5 



Length of carpus 12. 5 



Length of chela 8.6 



Breadth of chela 1.2 



Length of dactylus 5. 1 



Length of fourth perseopod 41 



Length of merus : 13 



Length of carpus 9. 5 



Length of propodus 8. 9 



Length of dactylus 3.8 



Length of fifth pera^opod 42 



Length of merus 12. 7 



Length of carpus 9.5 



Length of propodus 9.4 



Length of dactylus 3. 7 



Length of sixth somite of pereon 11. 3 



Height of sixth somite of pereon 8. 



Length of telson 14.0 



Length of inner lamella of uropod „ 13.0 



Breadth of inner lamella of uropod 3. 5 



Length of outer lamella of uropod 19. 5 



Breadth of outer lamella of uropod 4,5 



New Haven, Conn., April 29, 1885. 



