(XXXVI) | CRUSTACEA CASPIA. 301 
both anteriorly and posteriorly. In a lateral aspect (fig. 2), its dorsal face 
appears considerably arched in the middle, acquiring posteriorly an irregularly 
pectinated appearance owing to the strong dorsal projections issuing from 
the exposed part of the trunk. 
The carapace is rather large and deep, considerably longer than the 
exposed part of the trunk, and exhibits, in the lateral aspect of the animal 
(fig. 2), an irregular oval form. The branchial regions, occupying the greater 
part of the carapace, are well defined above and somewhat swollen, pro- 
jecting above in their posterior part as a rounded gibbous prominence. The 
gastric region, lying in front of the branchial regions, is somewhat flattened, 
and of the usual bell-shaped form (see fig. 1), being defined from the adjacent 
parts of the carapace by a well-marked curved fissure, and terminating 
anteriorly with a rounded lobe, which contains the visual organ. In front 
of the ocular lobe the pseudo-rostral projection is formed by the extremities 
of the lateral lobes of the carapace, which here meet along the dorsal line, 
though being defined from each other by a narrow longitudinal fissure. 
This projection is rather short, scarcely half as long as the gastric region; 
ard slightly upturned, terminating above in a sharp angle. Beneath it the 
antero-lateral corners of the carapace project on each side as a rather large 
and broad triangular lappet defined above by an even sinus. These lappets 
are somewhat expanded laterally, so as to be visible also in the dorsal view 
of the animal (fig. 1) on each side of the pseudo-rostral projection. The 
dorsal face of the carapace is somewhat vaulted in its posterior part, and 
decline anteriorly in an even slope to the base of the pseudo-rostral projection 
(see fig. 2). On the sides, the carapace is quite smooth, without any keels or 
folds. Its inferior edges exhibit, somewhat in front of the middle, a strong 
curve, and join the posterior edge, without forming any distinct angle. 
The exposed part of the trunk consists of 5 well-defined segments, which 
are provided with rounded, somewhat laterally-expanded epimera. The Ist 
segment is very narrow, band-like, and its epimera form anteriorly (see fig. 2) 
a narrow linguiform lobe, which somewhat overlaps the inferior edge of 
the carapace, while they posteriorly are partly covered by the rather large 
anterior lobe of the epimera of the next segment. The latter is considerably 
larger than the Ist, and exhibits dorsally 2 rather conspicuous, juxtaposed, 
rounded prominences. The 3rd segment is about as long as the 2nd, and 
is provided with a single laminar dorsal projection of inferior size and 
rounded form. The 2 posterior segments are considerably longer than the 
preceding ones, but less broad, and have each a very large erect, laminar, 
projection of narrow linguiform shape. The epimera of the last segment 
have the posterior corners slightly produced, though obtuse at the tip. 
Melanges biologiques. T. XIII, p. 465. 
