(XXXVI) | CRUSTACEA CASPIA. 319 
evenly vaulted above, without any keels or projections, epimera rather broad 
and laminar. Metasome considerably longer than the anterior division of the 
body. Eye well developed, with all 3 corneæ distinct. Antenne and oral 
parts of the usual structure. Legs comparatively slender; 2nd pair in male 
modified in the same manner as in P. pectinata. Uropoda slender, with the 
scape densely setiferous inside, and the rami equal-sized, both fringed inside 
with slender spines. Telson very small, semi-elliptical. Length of adult female 
about 5 mm, that of male nearly the same. 
Remarks. — The present species is at once distinguished from any of 
the preceding ones by its extremely slender and elongated body, strongly 
resembling in that respect some species of the genus Zphinoë. It is, however, 
a true Pseudocuma, as shown by the structure of the several limbs. 
Description of the female, 
The largest specimens attain a length of nearly 6 mm.; but generally it 
is far inferior in size, scarcely exceeding 4'4 mm. 
The general form of the body (see figs. 1 and 2) is exceedingly slender and 
elongated, more so even than in most other known Cumacea. The anterior di- 
vision of the body appears, from this cause, to be less sharply marked off from 
the posterior than in most other species, exhibiting a rather narrow oblong 
form. As seen from above (fig. 1), it has its greatest breadth about in the middle, 
and tapers very slightly, and quite uniformly, both anteriorly and posteriorly. 
In a lateral view (fig. 2), it appears somewhat thicker in its anterior part 
than posteriorly, and its upper contour forms a very slight and even curve. 
The carapace is comparatively small, not nearly attaining the length of 
the exposed part of the trunk, and exhibits, as seen from the side (fig. 2), 
a somewhat oval form, with the upper contour nearly straight, and the in- 
ferior edges evenly curved. The branchial regions are but faintly marked 
off from the adjacent parts of the carapace, and the gastric area exhibits 
the usual bell-shaped aspect, terminating in front in a semicircular ocular 
lobe. The pseudo-rostral projection is comparatively short, horizontal, and 
somewhat obtuse at the tip. Below it is a slight sinus defining it from the 
antero-lateral corners, which latter project but slightly, and are obtusely 
rounded. 
The free segments of the mesosome are quite evenly vaulted above, 
without any trace of keels or projections. The 2nd and 3rd segments are 
considerably larger than the others, and have the epimera very broad and 
laminar. The last segment is comparatively small, and has the epimera evenly 
rounded. ` 
Melanges biologiques. T. XIII, p. 488. 
