482 Echinogammarus 



expanded, bind margin slightly sinuous, not produced. üropods 1 and 2 short. 

 Cropod 3 long, outer ramus 6 or 7 times as long as the inner, with spines and 

 fascicles of long setae on both margins. Telson (Fig. 89) as in E. berilloni 

 (p. 481). Colour gi'eenish to yellowish, with a naiTOw brownish stiüpe on 

 bind mar^ of eacb segment. L. reacbing 43 mm. 



Lake Baikal, River Angara. 



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

 ßoss., V. lU suppl. p. 98 j 1899 Echinogammarus s., T. Stebbing in: Tr. Linn. Soc. London, 

 ser. 2 V.7 p. 429 | 1893 Gammarus fluviatilis (pari.), A. DellaValle in: F. Fl. Neapel, 

 V. 20 p. 930. 



9 unknown. — ö . Peraeon segment- 7 with 2 little groups of 2 or 3 

 spines on bind margin; pleon Segments 1 — 6 eacb witb dorsal spines in 

 2 — 4 groups adjoining bind margin, spines 18 — 22 on segment 1, 18 — 24 

 on segment 2, 18 — 20 on segment 3, 6 — 12 on segment 4, 8 — 6 on seg- 

 ment 5, 4 on segment 6. Eyes irregularly reniform, long, narrow, upper 

 end a little emarginate, reacbing bigb on top of bead, reddisb, invisible in spirit. 

 Antenna 1 nearly as long as body, tbrice as long as antenna 2, flagellum 87-jointed, 

 accessory flagellum 8-joLnted. Antenna 2, flagellum 16-jointed. Guatbopod 1, 

 6*^ Joint piriform, larger tban tbe oblong 6*^^ Joint of gnatbopod 2. Peraeo- 

 pods 3 — 5, 2*^ Joint broad, bind margin convex, carrying 8 — 10 sbort setae, 

 lower Corner projecting. Uropods 1 and 2 sbort, but m'opod 1 reacbing as 

 far back as tbe sbort uropod 3, in wbicb tbe inner ramus is about -/ö as long 

 as outer; botb caiTying a few simple setae. Telson not described. Colour 

 a very delicate sappbii-e-blue. L. 18 mm. 



Lake Baikal. Depth 300 m. 



4. E. czerskii (Dyb.) 1874 Gammarus c, B. Dybowsky in: Horae Soc. ent. Koss., 

 V. 10 suppl. p. 94 t. 1 f. 2; t. 3 f. 8 | 1899 Echinogammarus c, T. Stebbing in: Tr. Linn. 

 Soc. London, ser. 2 v.l p. 429 | 1893 Gammarus pungens (part.)?, A. DellaValle in: 

 F. FI. Neapel, v. 20 p. 928. 



Pleon Segments 1 — 6 witb regulär little pectinate groups of spines on 

 weak elevations scarcely oblique to tbe adjacent bind margin, on segment 1 

 usually 4 groups (2 median, 2 lateral), eacb with 3 or 4 spines, on Segments 

 2 and 3 a row of 4 groupg, preceded by 2 or 3 rows consisting eacb of 2 gi'oups, 

 on segment 4 a row of 3 groups, preceded by a row of 2 groups, on Seg- 

 ments 5 and 6 a row of 3 groups. Eacb group has usually 3 or 4 spines, 

 sometimes on segment 6 only 1 or 2. Eyes long reniform, widened below, 

 black. Aotenna 1 longer than the body, 1^* Joint rather shorter tban 2"^, 

 and only half as long as ultimate Joint of peduncle of antenna 2, flagellum 

 90-jointed, accessoiy flagellum 7 — 10-jointed. Antenna 2, ultimate Joint of 

 peduncle rather longer tban penultimate, flagellum 20 — 28-joLQted. Gnatbo- 

 pod 1 , 6*^ Joint piriform, much larger tban tbe naiTOwly oblong 6*^^^ Joint of gnatbo- 

 pod 2. Peraeopods 3—5, 2*^ Joint narrow, bind margin sligbtly convex, 

 lower angle very shortly produced. üropods 1 and 2 long, uropod 1 reacbing 

 the first or even tbe last quarter of uropod 3. uropod 3 very long, easily 

 detacbable, ^g as long as body, outer ramus 9 times as long as inner, sligbtly 

 beut, fringed with long, simple setae. Colour, red above, violet below, 

 appendages violet. L. about 28 mm. 



Lake Baikal. Depth 5 — 8 m. 



