T. XIIl] - CRUSTACEA CASPIA. 465 



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, 

 and 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 1st 

 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 1st, 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. 



Bulletin N. S. IV (XXXVI) p. 301. 



