399 Brandtia 



Synopsis of species: 



Median carina on all segnieiits of peraeon — 2. 

 Median carina only on last 2 or 3 segments of 

 peraeon — 3. 



j Median carina of pleon segment 1 carrying 2 spines 1. B. lata p. 396 



\ Median carina of pleon segment 1 devoid of spines 2. B. latissiina . . p. 396 



J Uropod 1 reaching beyond uropod 3 — 4. 



) Uropod 1 not reaching beyond uropod 3 5. 



j Uropod 3, outer ramus twice as loug as inner . . 3. B. tuberculata . j). 307 

 i Uropod 3, outer ramus' not twice as long as inner 4. B. moraTvitzii . p. 397 



( Uropod 3, inuer ramus more tlian half as long as outer 5. B. smaragdina . p. 398 

 ) Uropod 3, iuner ramus less than half as long as outer 6. B. fasciata . . . j). 398 



1. B. lata (Dyb.) 1874 Gammarus Uitus, B. Dybowsky in: Horae Soc. ent. Ross., 

 V. 10 suppl. p. 159 t.4 f. 5 I 1893 Atylus? l, A. Della Valle in:" F. Fl. Neapel, ». 20 p. 929 

 1899 Brandtia lata, T. Stebbing in: Tr, Linn. Soc. London, ser. 2 v.l p. 424. 



Back of peraeon flatly roof-shaped, median carina througbout, tuber- 

 cular, on segment 1 caiTving 1 or 2 backward bent spines; marginal carinae 

 strongly developed, obtusely projecting immediately over tbe side-plates; 

 on pleon segments 1 — 3 the median tubercular carina carries on segment 1 

 in ä 2, in Q 4 spines, on segments 2 and 3 of both sexes 4 forward 

 directed spines; corresponding to the marginal carinae of peraeon are small, 

 slightly cnrved elevations; pleon segments 4 — 6 arched, without carinae. 

 Head, front with tip-tilted rostrum, carrying 2 backward pointing spines, 

 top of head surmounted by 4 humps each carrying a backward directed 

 spine; an acute spine projecting from lower margin of each cheek. Side- 

 plates 1 — 4 setiferous, 1 — 3 cariuate. Lateral compression of body greatest 

 at lower part of side-plates. Eyes prominent, oval or renifonu, black. 

 Antenna 1 not long, in (5 little, in considerably, longer than antenna 2, 

 1^* Joint with hump near distal end above, flagellum 17 — 19-jointed. 

 Antenna 2, flagellum 7— 9-jointed. Gnathopods 1 and 2 subequal, 

 6*^ Joint oblong, but in gnathopod 1 with more oblique palm, which is 

 armed with 1 large and 2 sraall spines. Peraeopods 3 — 5. 2** Joint heart- 

 shaped, with 11 — 1.5 rather long setae ou bind margin. Uropod 3 smallei* 

 in Q than in d, rami nearly equal, ending in simple setae longer than the 

 rami, with delicate plumose setae on the inner margin. Telson broader than 

 long, cleft nearly to the base, with small setules ou the rounded apices. 

 Colour brownish yellow to brownish green, sometimes with a bright mai-k 

 across end of peraeon. L. 17 — 20 mm. 



Lake Baikal. Depth 2-20 m. 



2. B. latissiina (Gerstf.) 1858 Gammarus latisnmus, öerstfeldt in: Mem. pres. 

 Ac. St.-Petersb., o. 8 p. 288 | 1862 Brandtia latissima, Bäte, Cat. Amphip. Brit. 31us., 

 j). 129 t. 23 f. 5, 6 I 1893 Pontogeneia? l, A.Uella Valle in: F. Fl. Neapel, r.20 p.616. 929 

 1874 Gammarus latissimus -j- G.latior, B. Dybowsky in: Horae Soc. ent. Ross., ».10 

 suppl. p. 161; (). 158 t.4 f. 6. 



General shape as in ß. lata, median carina strongly developod, on pleon 

 segments 2 and 3 caiTying 3- -4 pairs of spines, but none on segment 1; 

 on pleon segment 3 the spines of the last pair almost on the bind margin and almost 

 twice as far asunder as those of the other pairs, the same being the case 

 on segment 2 only when the 4**> pair of spines is developed. Marginal 

 carina on each of peraeon segments carrying a short spine, this caiina 



