T. XIIl] • CRUSTACEA CASPIA. 489 



The eye is well developed, with all 3 corneae distinct. 



The superior antennae (fig. 3) have the basal joint comparatively short 

 and thick, whereas the 2 succeeding ones are rather slender and nearly 

 equal-sized. The flagella are normally developed. 



The inferior antennae and oral parts do not exhibit any essential difference 

 from those parts in the other species, and also the gnathopoda (fig. 4) are 

 constructed upon the very same type. 



Of the legs the 2 anterior pairs (figs 5 and 6) are normally developed, 

 and resemble those in P. gracilis. The 3 posterior pairs (figs 7, 8, 9), on 

 the other hand, are much more strongly built, with the joints much tumefied 

 and densely setous. The longitudinal relation of the several joints is also 

 somewhat different. Thus the basal joint is comparatively less elongated, 

 and especially in the last pair (fig. 9) very short and thick, bulging out 

 considerably on the outer side. The meral joint is in all pairs very large, 

 whereas the propodal one is quite short, of an oval form, and fringed on the 

 inner edge with the usual strong, unciliated setae, which are more developed 

 on the 2 last pairs than on the antepenultimate ones. The rudimentary ex- 

 opodite, issuing from the basal joint of the former, is distinctly Particulate, 

 and carries the 2 usual plumose setae. 



The uropoda (see fig. 10) are moderately slender, equalling in length 

 about y 3 of the metasome. The scape is provided on the inner edge with 5 

 ciliated setae. The rami are nearly equal-sized, and about the length of the 

 scape. The inner ramus has on the inner edge only 3 spinules in addition to 

 the 2 unequal spines issuing from the tip. The outer ramus, as in P. graci- 

 loides, has only a single spiniform seta on the inner edge near the tip, and 

 2 apical ones of unequal length. 



Thé telson (ibid.) exhibits a similar, semi-elliptical form to that in the 

 2 preceding species. 



The adult male (fig. 1 1 ) does not differ much from the female, as regards 

 the general from of the body, and is also of about same size. It is however 

 easily recognizable by the sexual characteristics, which are displayed in much 

 the same manner as in the other species. The uropoda (fig. 16) are, as usual, 

 somewhat more elongated than in the female, and the setae of the scape are 

 longer, and 6 in number. The inner ramus is armed on the inner edge with 

 no less than 10 spinules, and exhibits besides the usual fine ciliation of 

 the edge. 



Colour. — No colouring marks could be detected in the specimens 

 examined. They all exhibited a uniform, whitish colour. 



Occurence. — Of the present species, several specimens, almost exclusively 

 males, were collected by Mr. Warpachowsky at Stat. 15, located in the 



Bulletin N. S. IV (XXXVI) p. 325. 



