Echinogammanis 485 



Pleon Segments 1 and 2 more or less clearly furnished in the middle of 

 tho hinder dorsal margin with a median forward and 2 lateral hinder groups 

 of spinules on low elevations; segraent 3 having tbese preceded by 2 or 3 

 pairs of similar elevations carrying 4 or 5 spinules each; segments 4 and 5 

 eacli with a pair of slightly curved ridges pectinate ^ witb 5 or 6 spines, 

 Segment 4 having also 2 smaller lateral elevations with 2 or 3 spines each; 

 Segment 6 with a median pair of spines and 3 in a row on each side. 

 Eyes slightly reniform. Antenna 1 about ^^ as long as body, ratber longer 

 tban antenna 2, flageilum 30 — 32-joiuted, mucb longer tb an peduncle, accessory 

 flagellum about '^ lengtb of primary. Antenna 2, ultimateand penultimate joints 

 of peduncle long, subequal, flagellum 20-jointed. Gnathopods 1 and 2 subequal, 

 6*^ Joint moderately convex, almost rhomboidal, palm set with spines, more 

 or less straight truncate (Brandt). Peraeopods tolerably strong. with short 

 setae and spines. Uropod 1 moderately long and broad, reacbing about the 

 middle of uropod 3. Uropod 3, outer ramus about twice as long as telson, 

 thrice as long as inner ramus. Telson conical, each lobe with spines on 

 the bluut apex. L. reaching 25 mm. 



Ochotsk J^ay [Siberia]. 



10. E. testaoeus (i^yb.) 1874 Gammarus t., B. Dybowsky in: Horae Soc. ent. 

 Ross., ». 10 suppl. |).()0 1 189U Echinoijammarus t., T. IStebbing in; Tr. Linn. Soc. London, 

 ser. 2 V.7 p. 4^9 | 1893 Gammarus fiuvlatilis (part.)?, A. Della Valle in: F. Fl. Neapel, 

 I). 20 p. 931. 



Pleon Segment l without spines; segment 2 with a pair of lateral 

 groups of 5 or 6 spines each ; segments 3 and 4 and ofton 5 with 2 transverse 

 rows, the hinder composed of 2 middle and 2 lateral groups, the front generally 

 only of 2 lateral groups; segments 3 — 6 or 4 and 5 sometimes having the middle 

 and lateral group on each side coalesced; segment 6 with spines. Eyes narrowly 

 reniform, soraewhat widened below, black. Antenna 1 shorter than body, 

 twice as long as antenna 2, flagellum with 32 joints in o , to 50 in d, accessory 

 flagellum with 4 joints in 9 , to 7 in (5. Antenna 2, flagellum with 11 joints in 

 Q, to 23 in cJ, carrying calceoli. Gnathopod 1, 6*'^ Joint piriform, somewhat 

 larger than the oblong 6*^ of gnathopod 2. Peraeopods 3 — 5, 2*^ Joint broad, 

 bind margin convex, endiug below with projecting angle. Uropod 1 reaches 

 middle of uropod 3, inner ramus about ^/.^ — % as long as the 2-jointed 

 outer, which has simple setae on its outer margin, but plumose ones also 

 on the inner. Colour dark brownish, passiug into gTeenish, the whole body 

 spotted with yellow or bright greenish. L. 9 12—13, ö 21 mm. 



Lake Baikal (southern shore). 



11. E. sophiae (Dyb.) 1874 Gammarus s., B. Dybowsky in: Horae Soc. ent. 

 Ross., V. 10 suppl. p. Hl I 1899 Echmoyammarus s., T. Stebbi+tg in: Tr. Linn. Soc. London, 

 ser. 2 v.7 p. 429 | 1893 Gammarus fluviatilis (part.)?, A. Della Valle in: F. Fl. Neapel, 

 V. 20 p. 930. 



Pleon segments 1 — 3, spines on bind margin in a pair of lateral 

 groups, 2 or 3 spines to a group; segments 4 — 6 each with only 3 or 4 delicate 

 spinules, 1 or 2 in the median line, and 1 on each side in the place of 

 lateral gi-oups. Eyes small, oval or reniform, black. Antenna 1 nearly -/jj 

 as long as body, 1"* Joint shorter than 2^ flagellum 17 — 30-jointed, accessory 

 flagellum 3 — 6-jointed. Antenna 2, flagellum 8 — 14-jointed, with calceoli. 

 Gnathopods 1 and 2, 6*^ Joint piriform, larger and strenger in gnathopod 1 than 

 in gnathopod 2, and somewhat tumid at the base. Peraeopods 3 — 5, 2^ Joint 



