13S THE VOYAGE OF H.M.S. CHALLENGER. 



pyriform, cornea narrowed in upper part. Antennular peduncle shorter than carapace, 

 the two outer joints subequal, very slender in female, but strongly dilated in male. 

 Antenual scale projecting scarcely beyond second joint of antennular peduncle, oblong, 

 apex obliquely truncate. Second pair of legs, when fully extended, not attaining length 

 of body, carpal joint shorter than meral, and near the apex bearing a curved spine, 

 propodal joint with three strong ciliate bristles at inner edge ; terminal joint very 

 small, with apical spines subequal. Inner plate of uropoda longer than outer. 

 Lensfth 11 mm. 



Bcmarlcs. — Of this species I have had an opportunity of examining several specimens, 

 both adult females and males, whereas the other species are represented in the collection 

 merely by solitary specimens. Hence, the generic characters have been chiefly based 

 upon an anatomical investigation of the present form, which accordingly may be regarded 

 as the type of the genus. 



Description. — The length of the largest female specimen measures 11 mm. The 

 males are, as a rule, a trifle smaller. 



The form of the body is somewhat more slender in the females (PI. XXVI. fig. 1) 

 than in the males (fig. 19), but in both it would appear, on the whole, to be rather thick- 

 set. 



The carapace is somewhat short in proportion to its height, more especially in the males, 

 and lacks every trace of lateral denticles. Above it is distinctly carinate throughout a great 

 part of its length, the carina forming anteriorly an elevated crest which ends abruptly at 

 some distance behind the base of the rostrum. The latter is very narrow, perfectly straight, 

 and projects beyond the middle of the basal joint of the antennulas, its apex being sharply 

 pointed. The antero-lateral corners of the carapace are produced at an acute angle. 



The caudal segments are smooth above, and furnished with comparatively small 



rounded epimera. The last segment is rather elongate, about as long as the two 



preceding segments taken together, and exhibits a very small, unguiform preanal spine. 



The eyes are rather large, more especially in the male, irregularly pyriform, with the 



cornea considerably expanded below and somewhat narrowed in its upper part. 



The antennular peduncle in the female (fig. 3) is rather slender and elongate, though 

 a trifle shorter than the carapace, and exhibits a structure mvxch resembling that in the 

 genus Nematoscelis, the basal joint being considerably flattened, whereas the two outer 

 joints are very narrow, cylindrical, subecjual, and, taken together, somewhat longer than 

 the basal. Of the flagella, the outer part was broken off in all the specimens, but to 

 judge from the still remaining basal part, they would seem to have been extremely slender, 

 with narrow and elongate articulations. In the male, the antennular peduncle (fig. 21) 

 has a much more powerful development, the two outer joints being greatly dilated, and, 

 taken together, somewhat shorter than the basal. Of the flageUa, only the basal parts 

 remain, but, to judge from what is left, they must probably likewise have been rather 



