REPORT ON THE CUMACEA. 2/ 



very elongate, scape narrow and densely spinulose at inner edge, inner branch about as 

 long as scape, first joint almost twice the length of the two others taken together, all 

 three joints densely spinulose at inner edge ; outer branch with first joint very small, 

 second elongate and slender, slightly tapering, with short bristles on both edges. Length 

 of female, 12 mm. 



Remarks. — The present species being the only one as yet known, it is rather difficult 

 to point out the characters which should be regarded as strictly specific. Meanwhile, I 

 have thought it right to enumerate some structural details, which, from analogy with 

 related genera, may be assigned the value of specific characters. 



Description. — Of this form I have been able to examine numerous specimens, both 

 males and females. None of them, however, seem to have attained to sexual maturity, 

 as there are neither ovigerous specimens, nor males with fully-developed antennae and 

 pleopoda. The length of the largest female specimen is about 12 mm., that of the males 

 somewhat less. 



The form of the body (see PI. II. figs. 6-8) is extremely slender and elongate, with 

 the anterior division well defined from the posterior, and of a somewhat ovoid form. 



The carapace is of very considerable 'size, much larger than the exposed part of the 

 trunk. It is somewhat expanded laterally and distinctly sculptured by longitudinal 

 serrate keels, of which the following may be distinguished : — one median, running along 

 the anterior part of the dorsal surface and terminating at the end of the frontal lobe ; 

 two subdorsal keels on each side of the strongly arched branchial regions, the inner one 

 the shorter and curved, occupying the most prominent part of that region and confined 

 to the posterior half of the carapace, the outer keel reaching anteriorly to the base of the 

 frontal lobe ; finally, on each side a lateral keel horizontally encircling the carapace and 

 continued anteriorly along the edges of the pseudorostral projection to its very apex. 

 There is also a more or less distinct but very small and interrupted keel, also serrate, on 

 the posterior part of the carapace between the lateral and outer subdorsal keels. 

 Beneath the lateral keel, on the ventrally inflected parts of the carapace, a slight longi- 

 tudinal keel may moreover be noticed (see PI. III. fig. 1), but this keel, unlike the 

 others, is quite smooth. The pseudorostral projection is very short and somewhat 

 upturned ; it is not limited beneath by any distinct notches, and there are no 

 projecting angles marking off" the inferior from the anterior edges of the carapace. As 

 seen from above (PI. II. fig. 6) the carapace appears rather broad, on account of the 

 expanded sides, its breadth being considerably greater than its height ; anteriorly it is 

 evenly rounded, without any distinctly marked projection in the middle. The ocular 

 lobe (see PL III. fig. 2) is very small, and of a short conical form, without any trace of 

 pigment or visual elements ; it does not extend, as in the above described species of the 

 genera Cyclaspis and Vaunthompsonia , along the dorsal side of the pseudorostral 

 projection, the lateral lobes of which meet in front of it. 



