310 On some Species of Leptocheirus. 



propodos ; tlie propodos is one third shorter than tlie carpus ; 

 the nail only sliglitly bent, equal in length to one third of 

 the propodos. Tlie first perseopods (fig. 7) have the meros 

 about one third longer than the carpus and equal in length to 

 the gradually tapering propodos ; the nail is long and slender 

 and is as long as two thirds of the propodos. The last 

 perffiopods (fig. 8) have the propodos strong, with setae on both 

 sides, and only slightly longer than the preceding joint. The 

 uropods are furnished with spines of moderate size. 



The male differs considerably from the female in the 

 anterior part of the body. The first segment of the meso- 

 some is as long as the head and about twice as long as the 

 following segment. The first gnathopods have the coxa of 

 much larger size and quite different shape, it being rhom- 

 boidal in outline ; the gnathopod itself is much more deve- 

 loped than in the female, larger and longer ; and the palm of 

 the propodos is slightly concave instead of very slightly 

 convex, and is furnished with a short, stumpy, strong spine 

 at its commencement. The coxa of the second gnatiiopods 

 is largely developed and extends downwards beyond those of 

 adjoining limbs. 



Length 15 mm. 



1 am indebted to Prof. S. I. Smith for specimens of this 

 species from Long Island and also from Vineyard Sound. As 

 regards distribution he writes {I. c.) : — " Common on the 

 whole coast of New England upon muddy bottoms, and 

 north to Labrador. In depths it extends down to 150 fathoms, 

 and probably much farther." 



The following diagnostic characters of the North-Atlantic 

 species of Leptocheirus may be useful : — 



Coxae (epimera) of gnathopods and following segments 



having their hinder margin furnished with spines. . pinguis. 

 Coxae without such spines 2. 



2. Finger of second gnathopods unguiform 3. 



Finger of second gnathopods stiliform, tipped with 



setae 6. 



3. First segment of urosome with spine-processes on 



hinder margin 4. 



First segment of urosome without spine-processes .... 5. 



4. A central and two lateral spine-processes guttatus. 



No central, but two lateral spine-processes bispinosus. 



5. Nail of posterior gnathopods cleft pilosus. 



Nail of posterior gnathopods simple, not cleft subsalsus. 



6. Coxa of first gnathopods very small, terminating in a 



fine point della vnllei *. 



Coxa of tirst gnathopods quadrate, front corner scarcely 



produced pecthiatus. 



* della rallei, Ste\)hing, = Proto7nedeia fasciata, Costa (nee Kroyer). 



