CRUSTACEA CASPIA. 475 



pairs of coxal 2)lates not very deep, but quadrangular in form and perfectly 

 smooth; 4tli pair but slightly emarginated posteriorly. Epiraeral plates of 

 metasome scaro^ly produced at the lateral corners. Urosome rather small, 

 and perfectly smooth. Eyes of moderate size and rounded form. Superior 

 antennae not much elongated, peduncle rather short, with the 1st joint much 

 the largest, flagelium e.xceeding the peduncle in length and composed of 

 about 10 articulations, accessory appendage extremely minute, biarticulate. 

 Inferior antennae scarcely half as long as the superior. Anterior gnathopoda 

 rather small, with the propodos oval quadrangular in form; posterior ones 

 nuicli more elongated, with the propodos sub-linear in sliape. Pereiopoda 

 moderately elongated and almost naked, dactylus in all of them hook-shaped, 

 terminating in a very sharp point; basal joint of last pair not diffeiing much 

 from that of the 2 preceding pairs. Last pair of uropoda with the outer 

 ramus scarcely longer than the basal part, inner scale-like. Telson semi-lunar 

 in form, cleft very narrow. Length of adult female S'/g mm. 



Remarks. — This is as yet the only known species of the genus, and 

 may easily be recognized from the otlier Caspian Amphipoda by its elong- 

 ated, subcylindrical body and the unusually poor development of the inferior 

 antenuic. 



Description. — The length of fully adult female specimens measures 

 only S'/a mm., and tliis form is accordingly of rather small size. 



The body (see tig. 13) is remarkably slender and elongated; perfectly 

 smooth, and not at all compressed, being nearly cylindric in form. The 

 anterior division, comprising the cephalon and mesosome, is fully twice as 

 long as the i)osterior one, all its segments being of nearly equal length. 



The cephalon does not exceed in length the 1st segment of the meso- 

 some, and is but very sliglitly produced in front between the bases of the 

 superior antenucc. The lateral lobes are evenly rounded, and beliind them 

 the inferior edges of the head form on each side a rather deep emargination 

 encircling the globular basal joint of tiie inferior antennae. 



The anterior pairs of coxal plates are but little deeper than the cor- 

 responding segments, but comparatively broad, and they slightly increase in 

 size posteriorly. The 1st pair (see tig. 21) are almost quadrate in form, the 

 2 succeeding ones oval quadrangular. The 4th pair are not much broader 

 than the preceding pairs, and but very slightly emarginated posteriorly. 



The 3 posterior pairs of coxal plates are rather small, and of usual ap- 

 pearance. 



The epimeral plates of the metasome are not particularly large, and the 

 last 2 are scarcely produced at all at the lateral corners. 



•taa.-MaT. cip. 305. 5 5 



