KEPOK.T ON THE ISOPODA. 67 



The head is very long, equalling the two first segments of the thorax taken together 

 in its antero-posterior diameter ; on either side, about halfway between the anterior and 

 posterior margin of the head, is a strong hooked spine : the frontal region of the head, 

 between the attachments of the antennae, is extremely narrow. 



Of the first four segments of the thorax the first is rather shorter than the rest, 

 which are subequal ; the three last of these segments are furnished with a longish 

 median spine, as in Eurycope fragilis. 



The lateral margins of these segments, as in so many other species of the genus, are 

 prolonged into a forwardly directed spine, which is in the present species extremely 

 delicate and slender though not specially long ; behind the spine are a number of 

 inconspicuous denticulations, and in the fourth segment one of these latter is especially 

 prolonged and ecpials the lateral spine in length ; in this segment, therefore, there are 

 two instead of only one lateral spine on either side. 



The three posterior thoracic segments, as is usual in this genus, differ markedly in 

 their character from the anterior segments of the thorax ; they are wide and more 

 convex, and V-shaped ; the last of these segments has a straight posterior margin 

 instead of a very concave one, but it includes possibly one at least of the anterior 

 segments of the abdomen ; the first two of these segments have each a pair of spines 

 placed one on each side of the dorsal median line ; in the third segment there are only 

 faint indications of these spines ; laterally each of these segments is prolonged into a 

 flattened, forwardly. directed spine. 



The abdominal shield has a very peculiar form, which serves to distinguish the 

 species from any other ; it is somewhat oval in form and terminates behind in a some- 

 what obtusely pointed extremity ; in front of the articulation of the uropoda are a pair 

 of lateral spines, which are curved forwards in a crescentic shape ; in front of these again, 

 but some way behind the antero-lateral margin of the caudal shield, are another pair of 

 lateral spines, straighter than the more posterior pair of spines. The upper surface of 

 the caudal shield is divided into three areas by two longitudinal furrows ; the central 

 area is the widest and has a pair of median spines situated one behind the other ; the 

 first of these is placed close to the anterior boundary of the abdominal shield and corre- 

 sponds to a similar spine in Eurycope fragilis, the second rather more than halfway down. 



The first pair of thoracic appendages, like those of other Eurycope, are considerably 

 smaller than those which follow. 



The uropoda consist of a basal joint, which is stouter than the succeeding joint ; I did 

 not observe the uropoda to be biramose, but do not wish to speak with certainty on the 

 point; they arise from just underneath the posterior lateral spines of the abdominal 

 shield. 



Station 76, off the Azores, July 3, 1873; lat. 38° 11' N., long.' 27° 9' W. ; depth, 

 900 fathoms ; bottom temperature, 40° F. ; Pteropod ooze. 



