REPORT ON THE CUMACEA. 13 



Remarks. — This species may easily be distinguished from the typical form, Cydaspis 

 longicaudata, by the less tumid carapace and the sculpture of the same as well as that of 

 the tail. The ocular lobe has, moreover, at the end distinctly developed visual elements, 

 whereas in the typical species the eye is quite wanting, and the ocular lobe very short 

 and rounded. The species is also very diflerent from the Mediterranean form, Cydaspis 

 cornigera. 



Description. — I have been able to examine several specimens of this form, both 

 males and females, but none of them seem to be quite full-grown. The largest 

 specimen, represented on PI. I. figs. 1, 2, is a young male. The length of this 

 specimen is 10 mm., whereas that of the largest female specimen (fig. 3) is only 

 8 mm. 



The form of the body in both sexes (see PI. I. figs. 1-3) is very slender, with the 

 anterior part, as in the typical form, suddenly and markedly dilated, almost club-shaped. 



The carapace is large and deep, though somewhat more compressed than in the 

 typical species, its thickness being rather less than its height (compare figs. 1, 2). It is 

 somewhat gibbous in its posterior part, the strongest dorsal curvature lying rather behind 

 the middle, from which point the dorsal line declines almost in a straight line towards 

 the pseudorostral projection. The latter, to which generally the very improper term of 

 "rostrum" has been applied, is quite short and obtusely truncate at the tip, and, as 

 usual, is chiefly composed of the antero-lateral lobes of the carapace projecting in front of 

 the antennal segment. Immediately beneath this projection there occurs on each side a 

 distinct notch, limited by a short projecting angle, from which a short elevated ridge 

 runs backwards over the carapace. The inferior edges of the carapace are evenly curved 

 and join the posterior margin at an obtuse angle. On each side of the carapace, somewhat 

 posterior to the middle, a slight crescent-shaped prominence is seen running transversely 

 down the sides to the inferior edge. Above, this prominence joins an obliquely 

 longitudinal ridge, that begins at the most elevated part of the carapace, limiting 

 posteriorly the gastric region, and disappears at the sides of that area ; between this ridge 

 and the above-mentioned short lateral keel in one of the specimens (fig. l), a somewhat 

 irregular forked prominence occurs, joining both in the anterior part of the carapace. 

 The gastric area (see fig. 2) exhibits, as usual, a somewhat bell-shaped form, and is limited 

 to each side by a distinctly marked fissure. From the extremity of this area the ocular 

 lobe is seen projecting. This lobe exhibits a rather peculiar appearance, being continued 

 along the whole upper side of the pseudorostral projection to its very tip ; it is (fig. 4) 

 almost cylindrical and slightly swollen at the extremity, where an assemblage of 

 distinctly marked and regularly arranged lenses or cornea-facets occurs, as also interiorly 

 a dark pigment. 



Only four segments of the trunk are found to be exposed behind the carapace. Of 

 these, the first is firmly connected with the carapace and almost of the same height as 



