Brachyuropus 393 



1. B. grewingkii (Dj^b.) 1874 Gammarns g., B. Dybowsky in: Horae Soc. 

 ent.Ross., j\ 10 suppl. p. 150 t.2 f.4 | 1893 Cran^OMyx? ^r., A.DellaValle in: F.FI. Neapel, 

 «.20 p. 928 j 1899 Brachyuropus g., T. Stebbing in : Tr.Linn. Soc. London, ser. 2 v.l p.424. 



Median dorsal carina represented on all segments, except pleoii Seg- 

 ments 4 — 6 or 5 and 6, by streng teeth, usually strengest on peraeon Seg- 

 ments 5 — 7 and pleon segments 1 and 2, all, and especially tliose on pleon 

 Segments 1 — 3, laterally strongly compressed, liinder pleon segments dorsally 

 ronnded and completely smooth. Lateral marginal carinae on peraeon seg- 

 ments weak, tubercular (a variety with donble series of small tubereles on 

 peraeon segments 6 and 7 aud pleon segments 1 — 3). Head, surface rough, 

 rostrum short, obtusely pointed; beliind the eye from tlie cheek projects a 

 long, pointed, obliquely outward and forward directed tooth. Side-plates 1 — 4 

 more or less deeply emarginate below between 2 acute points, the binder 

 longest. Side-plate 4 on lower part of its surface provided with a down- 

 ward and backward directed, strong, pointed, flattened tooth, reaching fai* 

 over its bind angle. Pleon segments 1 — 3, postero-lateral augles acute (in 

 tigure ronnded), Eyes weakly developed, white, dimly showing through the 

 pellucid integument, sometimes not disceraible at all. Antenna 1 more than half 

 as long as body, about thrice as long as antenna 2, flagellum with more than 00 joints. 

 accessory flagellum 22-jointed. Antenna 2. ultimate Joint of peduncle shorter 

 than penultimate, flagellum 14-jointed. Gnathopods 1 and 2, 5**^ Joint short, 

 6*^ piriform, narrowing to the tinger hinge, palm very obli(jue, much longer 

 than bind margin, defined by a spine, and having a prominent spine near the 

 middle (in figure) ; this Joint (in figure) is louger in guathopod 1 than in 

 gnathopod 2. Peraeopods 3 — 5, 2*^ Joint narrowly heart-shaped (in flgure; 

 narrowly oblong, a little widened proximally), without setae on bind margin. 

 Peraeopod 4 as long as body. Peraeopod 5 subetjual to peraeopod 4 (in flgure). 

 [Iropods 1 and 2 sti'ongiy developed, reaching about equally far, rami thickly 

 fringed with simple setae. Uropod 3 scarcely ^/gg — Vao '^'^ ^^^S '^'^ body, 

 outer ramus fringed with simple setae, 3 — 5 times as long as inner, which 

 has only an apical seta. Telson broader than long, with couvex margins 

 narrowing to a shallowly emarginate apex, with angies only subacute. Oolour 

 dark horn-yellow to yellowish white. L. reaching 66 mm. 



Lake Baikal. Depth 100 — 1000 in. 



2. B. reichertii (l-)yb.j 1874 Gammarus r., B. Dybowsky in: Horae Soc. ent. 

 Koss., V. 10 suppl. p. 42, 152 t. IB f. 4 | 1893 Cranyonyx reicherti, A. üella Valle in : 

 F. Fl. Neapel, f. 20 p. 930 | 1899 Brachyuropus reichertii, T. Stebbing in: Tr. Linn. Soc. 

 London, ser. 2 v. 7 p. 424. 



Median dorsal carina as in B. grewingkii, but the teeth higher, more 

 acute, less compressed, longest on pleon segments 1 and 2 ; peraeon segments 

 1 — 4 with Single weak lateral carina, segments 5;;-7 with lateral row of 

 little roundish tubereles, and marginal prominences carina-like, tuberculate 

 in the middle ; pleon segments 1 — 3 with lateral tubereles on bind margin. 

 Head, surface rough, rostrum a short, blunt hump; from the cheek projects 

 forward, outward, and upward a slightly beut tooth. Side-plates 1—4 below 

 shallowly emarginate, the augles blunt and short. From the surface of side- 

 plate 4, and nearly at right angies to it, a veiy long, ronnded tooth is directed 

 horizontally outward. Distance between apices of this pair of teeth equal to 

 2^3 — 3 times greatest breadth of body without the teeth. Pleon segments 1 — 3, 

 postero-lateral angies rounded. Kyes as in B. grewingkii. Antenna i^/g 

 as long as body, 3 — 4 times as long as antenna 2, flagellum 46-jointed, 

 accessory flagellum 12-jointed. Antenna 2, ultimate Joint of peduncle shoiiier 



