CRUSTACEA CASPIA. 355 



liquely oblong, being- expanded at the upper part posteriorly to a rounded, 

 minutely setiferous lobe. The last pair (tig. 8) have the basal joint con- 

 siderably larger than that of the 2 preceding pairs, and of a regular 

 oval form, with the posterior edge slightly curved and fringed with small 

 bristles, the infero-posteal corner being produced to a broadly rounded lobe 

 extending to the end of the ischial joint. 



The 2 anterior pairs of uropoda. have the rami subequal and of a narrow 

 linear form, being spinous only at the tip. 



The last pair of uropoda (fig. 9) are of moderate size, and have the basal 

 part, as usual, armed at the end below with a transverse row of strong spines. 

 The inner ramus is less rudimentary than in most other Caspian species, 

 being about half the length of the outer. It is conically tapering and carries 

 at the tip a slender spine and 2 or 3 delicate bristles. The outer ramus is 

 about twice as long as the iiasal part, and has the terminal joint well de- 

 veloped, about half the length of tlie proximal one. The latter has outside 

 2 small fascicles of spines and inside about 4 slender setae. 



The telson (fig. 10) is fully as long as it is broad at the base, and is, as 

 usual, cleft to the base, the cleft widening gradually distally. The lateral 

 lobes are comparatively narrow, and each carry at the somewhat truncated 

 tip 2 slender spines. 



Occurrence. — Some specimens of this form were collected by Mr. War- 

 pachowsky at St. 2, located ofl' the Tschistyi-Bank ; a single specimen was 

 moreover found at St. 16, lying east of the island Swjatoj. 



In the collection of Dr. Grimm this species seems not to be represented. 



12. Gammarus similis, G. 0. Sars, n. sp. 



(PI. XI, figs. 11—20). 



Specific Characters. — Very like the preceding species, though not 

 nearly so much compressed. Lateral lobes of cephalon somewhat projecting 

 and obtusely rounded at the tip. Anterior pairs of coxal plates densely setous 

 at the terminal edge; 1st pair but very slightly widening distally; 4th pair 

 not so broad as they are deep. Epimeral plates of metasome about as in G. 

 compressus. Urosome somewhat more slender than in that species and 

 smooth above, last segment with 2 small spiuules on each side of the dorsal 

 face. Eyes oblong oval in form, with dark pigment. Antennae comparatively 

 short and nearly equal-sized, the superior ones with the 1st joint of the 

 peduncle very large, fiagellum somewhat longer than the peduncle, ac- 

 cessory appendage 4 — 5-articulate. Gnathopoda in female nearly as in G. 

 compressus; those in male somewhat stronger and rather unequal, the post- 



*H3.-MaT. CTp. 335. 13 23* 



