402 Mr. Lubbock on new species of Entomostraca. 



and equal to one another ; two of these are situated at the apex, 

 one on the posterior side of the second segment, one on the an- 

 terior side of the fourth, and the others at nearly equal distances 

 along the antenna. The penultimate anterior and the ante- 

 penultimate setse are short. This diffusion of the long setae over 

 the whole length of the antennae is very peculiar, and similar to 

 what occurs in the genus Euchata. 



The second pair of antennae, PL X. fig. 3, are also abnormal, 

 and resemble those of no other species with which lam acquainted. 

 They consist, as usual, of two branches, one of which is long 

 and three-jointed, and bears at the apex two tufts, one of six, 

 the other of eight long hairs. The second segment bears one 

 hair, and the basal one eight, increasing in length from the base 

 towards the apical end. This branch is neither rounded nor 

 truncate at the free end, but ends in a sharp edge like an adze, 

 or the gnawing tooth of a Rodent. The smaller branch is not 

 jointed, and is truncate, with eight hairs at the end. 



The first pair of legs (or, according to Prof. Dana^s nomen- 

 clature, the second), PI. X. fig. 4, have the outer ramus three- 

 jointed, the first and second each bearing one hair on the inner 

 side, and, as well as the third, a short spine on the outer margin. 

 The inner branch consists of two segments, of which the basal 

 is long and narrow, with parallel sides, and three hairs at equal 

 distances. 



The fifth pair of legs (PI. X. fig. 5) have only one ramus, are 

 four-jointed, and have no plumose setae, and only one long, naked 

 hair at the base. 



The abdomen has four subequal segments and short lamellae, 

 with six diverging hairs, of which the fourth (counting from the 

 outside) is a little the longest; the third and fifth are rather 

 shorter, the second again rather shorter, and the first and sixth 

 are quite small. 



The cephalothorax had, in the greater number of specimens, 

 three very minute spines on the posterior margin of the last 

 segment ; a few specimens, however, had four ; and one or two 

 had only two, or even none. 



I also found other specimens which had the abdomen only 

 three-jointed, and the posterior legs (PI. X. fig. 6) consisting of 

 a basal part bearing on each side a long and large hair, and of a 

 small second segment ending in a stout spine about half as long 

 as these hairs. These specimens I have little doubt were the 

 females of this species, since they agreed in all the other charac- 

 ters, especially in the form of the cephalothorax, the structure of 

 the two pairs of antennae, and the first pair of legs. 



I have described this species at length, in order to distinguish 

 it from others that may hereafter be discovered ; from all those 



