CRUSTACE A. 



and the pterygostomian region, as well as the lower portion of the 

 orbit near the buccal area, has a sparse covering of short hairs. 



II inornatus, Dana, Proc. Acad. Nat. Sci. Philad., 1851, v. 248. 



Genus OCYPODA. 



In Ocypoda, the body is very nearly rectangular in form, the sides 

 not converging backward, as is usual in Gelasimus. The lateral 

 margin of the upper surface has a distinct border, which converges 

 somewhat behind, from a point a short distance from the anterior 

 angles, yet the convergence is much less than in Gelasimus ; but the 

 lower lateral margin upon the sides does not incline inward at all, 

 and even diverges from the medial line in some species. Besides this 

 character, the less equal hands in males, the pointed fingers of both 

 hands, and the stout eye-peduncles, covered with the cornea nearly to 

 the base, remove the species from Gelasimus. 



These species are able to make a sound, by means of a series of 

 minute ridges on the inner surface of the hand, which acts like a rasp 

 against a prominent edge on the second joint of the same pair of legs. 

 The surface adjoining both the rasp and the edge is usually short 



hairy. 



In males, the first suture in the sternum is posterior to the last 

 articulation of the abdomen, while it is anterior in Grapsus. 



1. Oadi ' pedunculus apice non productvs. 



Ocypoda rhombea, Fair. 



Plate 19, fig. 8a, male, natural size; b, abdomen and sternum; c, 

 hand. 



Kio Janeiro. 



Length of a female, seventeen and one-fourth lines; breadth across 

 middle, twenty-one and a half lines; ratio, 1 : 1-25 ; length of a male, 

 sixteen lines; breadth across the middle, nineteen and a half lines; 



