new West-Indian Tanaid. 51 



First Gnathopods. — These chelipeds are remarkable botii 

 for the threatening gape of the chela and for their length, 

 which is double that of the animal's body. The second joint 

 is the stoutest, yet not much dilated, a little longer than 

 broad. The third joint is short, almost triangular. The 

 fourth is of great length, narrowest near the base and nowhere 

 very wide. The fifth is still longer, with a curvature at its 

 base adapted for the folding together of these long slender 

 joints ; its narrow immovable digit forms less than half of 

 the total length of the joint and ends in a sort of pointed claw 

 over which three setules are distributed, another setule occu- 

 pying a small prominence of the inner margin near the 

 base of the claw. The movable finger is somewhat longer 

 than the immovable one, slender, pointed, curved, with 

 irregular margins. 



Second Gnathopods. — As usual in this group, these are 

 gnathopods only in name, and differ but slightly from the 

 following ambulatory feet. They are scarcely, if at all, larger 

 than the fifth perseopods, having the second joint narrower, 

 but the fourth and fifth joints a little wider than is the case 

 in that pair. 



Perceopods, — The general structure is the same in all. The 

 second joint is the longest, in the last three pairs somewhat 

 dilated. The third joint is very short, the fifth joint is a 

 little longer than the fourth, and the sixth considerably longer 

 than the fifth. There are some spinules about the distal end 

 of the sixth joint. In the first and second pairs the finger is 

 small, in the other three pairs it is nearly as long as in the 

 second gnathopod. 



Pleopods. — AH the five pairs are constructed as in Lepto- 

 chelia. 



Uropods. — The peduncles are a little longer than broad. 

 The inner branch has six joints, of which the first is the 

 widest, the fourth the longest. The outer branch has two 

 joints, together not equalling the length of the first joint of 

 the inner branch. AH the joints of the branches are seti- 

 ferous. 



Length. — From head to tail the specimen measured less 

 than a tenth of an inch. 



Habitat. — The single specimen (a male) comes from An- 

 tigua, where it was found at Long Island, at the mouth of 

 Parham Harbour, in shallow water, with sandy bottom, 

 covered with algee, by Mr. W. R. Foi'rest ; and I do myself 

 the pleasure of associating the species with the name of that 

 acute observer. 



4* 



