REPORT ON THE CUMACEA. 39 



pairs successively decreasing in length and densely beset with ciliated bristles. Uropoda 

 with inner branch longer than outer, first joint scarcely twice as long as second, both 

 armed with scattered denticles at inner edge. Length, 10 mm. 



Remarks. — The present species is nearly related to Leucon longirostris, described by 

 the author from an imperfect specimen procured during the Swedish Expedition in the 

 frigate " Josephine." It may, however, easdy be distinguished by the rather different 

 form of the pseudorostral projection, the length of which in proportion to the carapace 

 is also much greater. 



Description. — The sole specimen procured is a young female, in which the marsupial 

 pouch has not yet been developed. Its length is about 10 mm. The form of the body (see 

 PI. V. figs. 1, 2) is extremely slender, more so than in any other of the known species. 



The carapace (see fig. 3) is distinctly compressed and of the usual form, with the 

 dorsal crest well marked, but denticulate only in its anterior half, the denticles being 

 rather few in number (seven), and hence more widely separated from each other. The 

 pseudorostral projection is quite unusually elongate and slender, almost equalling the 

 carapace in length, and tapers gradually to the tip, which is narrowly truncate. It is 

 somewhat ascending and has the lateral edges provided with a few scattered bristles and 

 a single small denticle behind the middle. The anterodateral corners of the carapace are 

 less produced than in the preceding species and almost rectangular. The anterior edges 

 joining the pseudorostral projection are strongly denticulate and have a distinct rounded 

 sinus below the middle, from the bottom of which the rudimentary antennae are seen to 

 project. The inferior edges of the carapace form a slight angle at the middle and are, 

 as usual, strongly denticulate in the anterior half. 



The five exposed segments of the trunk taper successively posteriorly, and the last of 

 them does not exceed the caudal segments, either in height or in breadth. 



The tail is considerably longer than the anterior division of the body and very 

 slender. Its segments increase successively in length to the penultimate, which is by far 

 the longest. The last segment (see fig. 4), on the other hand, is quite short and almost 

 pentagonal, with the end produced to an obtusely triangular projection arching over the 

 anal orifice. 



The antennulae (see fig. 3) are comparatively rather large, though not nearly reaching 

 to the tip of the pseudorostral projection. They are more especially distinguished by the 

 unusual development of the inner flagellum, which in this case cannot properly be said 

 to be rudimentary, since it fully equals in length the first joint of the outer one ; it is, 

 however, as usual, composed of only a single joint, which bears at the tip several stiff 

 bristles. 



The two anterior pairs of legs (see fig. 1) do not seem to differ materially from those 

 of the preceding species. This is also the case with the succeeding legs, with this 

 difference, however, that they are much more richly supplied with ciliated bristles. 



