Brandtia 397 



represented by lateral swellings ou pleon segments 1 — 3; pleon segments 4 — 6 

 much longer than in B. lata. Head with spines as in B. lata and 2 additioual 

 lateral pairs. Side-plates 1 — 4 all carinate, but not setiferous. Eyes prominent, 

 oval or reniform, black. Auteunae 1 and 2 in general as in B. lata, bnt 

 P* Joint of antenna l with 2 humps in line, the front one anned with 

 2 backward directed spines, flagellnni with 15 — 27joints, of which in the ä tho 

 3*i, in the the 4*** is longest. Gnathopods 1 and 2 snbequal, G*** Joint slender. 

 with slightly convex margins (I)ybowsky), in gnathopod 1 6*'^joiutmore elongate, 

 in gnathopod 2 more rhomboidal, with palm more obliquely truncate (Gerstfeldt). 

 Peraeopods 3 — 5, 2*^ Joint heart-shaped, narrower than in B. lata, with extremely 

 siiort, distant, setae on bind margin. Uropod 3 shorter in 9 than in d, 

 but never riidimentary. Colour in general greenish brown, parts of head 

 and peraeon brighter. L. 19 — 27 mm. 



Lake Baikal. River Angara. 



•■{. B. tuberculata (Dyb.) 1874 Gammarus tuberctilatvs, B. Dybowsky in: Horae 

 Soc. ent. Boss., vAO suppl. p. 161 | 1893 Atylus? t., A. Della Valle in: F. Fl. Neapel, 

 w. 20 p. 931 I 1899 Brandtia tuberculata, T. Stebbing in: Tr. Linn. Soc. London, ser. 2 

 «'.7 p. 424. 



The median cariua weakly developed as longish tubercles on peraeon 

 segments 6 and 7 and pleon segments 1 — 3 ; marginal carina represented by a 

 rounded, smooth, not very prominent swelling immediately over the side-plates 

 of all peraeon segments and pleon segments 1—3." Head, rostrum a short 

 obtuse point. Side-plates 1 — 4 setiferous. Eyes round oval, broader below 

 than above, black. Antenna 1 less than ^2 ^s long as body, twice as long 

 as antenna 2, l**^ Joint broad, flagellum 24-jointed. Antenna 2, flagellum 

 8-jointed. Gnathopods 1 and 2 snbequal, 6^^ Joint piriform, palm defined 

 by 3 spines, finger long, slightly beut. Peraeopods 3 and 4, 2** Joint expanded 

 above, all the bind margin beset with rather long setae. Peraeopod 3, 

 2'^ Joint greatly widened below. Uropods 1 and 2 reach beyoud uropod 3, 

 which is ver}" short, outer ramus twice as long as inner, with 3 — 7 spines 

 on apex and 2 on outer margin, inner ramus with only 2 spines, both 

 apical. Telson divided. Colour greyish white or clear brown, with naiTow 

 dark stripes across the segments. L. 16 mm. 



Lake Baikal. Litoral. 



4. B. morawitzii (Dyb.) 1874 Gammarus m., B. Dybowsky in: Horae Soc. 

 ent. Boss., v. 10 suppl. p. 163 | 1893 Atylus? m., A. Della Valle in: F. Fl. Neapel, r.20 

 p. 929 I 1899 Brandtia m., T. Stebbing in: Tr. Linn. Soc. London, ser. 2 v.l p. 424. 



Median carina distinct on the convex peraeon segments 6 and 7 and 

 pleon segments 1 — 3; spines on pleon segments 5 and 6 exti-emely delicate; 

 whether marginal carinae are present or absent is not stated. Head, rosti"um 

 broad, rounded, little advanced. Side-plates 1 — 4 setiferous. Eyes moderately 

 large, roundish, convex, black or dark red. Antenna 1 rather more than ^/g 

 as long as body, and about ^/g longer than antenna 2, 1^* Joint stout, flagellum 

 14 — 18-jointed. Antenna 2, flagellum with 7 or 8 joints. Gnathopods 1 

 and 2 small, slender, 6*^ Joint oval in gnathopod 1, oblong in gnathopod 2. 

 Peraeopod 3, 2^ Joint on upper margin strongly rounded. Peraeopod 4, 

 2* Joint heart-shaped. Peraeopod 5, 2^ Joint broader than in peraeopods 3 and 4, 

 bind margin evenly rounded. Uropod 3 exti-emely short, outer ramus scarcejy 

 longer than peduncle, 1-joir.ted, with 4 spines on apex, 2 on outer margin; inner 

 ramus '^% as long as outer, with 1 — 3 apical spines. Each half of telson 



