398 Brandtia, MicruropuB 



like a coiie witli broacl base. Colour grejlsb white, sometimes dark longitudinal 

 stripe ou the back. L. 10 mm. 

 Lake Baikal. Depth 20 m. 



5. B. smaragdina (Dyb.) 1874 Gammarus smaragdinus -\- Q. s. var. intermedins. 

 II Dybowsky in: Horae Soc. ent. Boss., *;. 10 suppl. p. 164 t. 11 f. | 1893 Atylus? s., 

 A. DeUa, Valle in: F. Fl. Neapel. ('.20 p. 930 | 1899 Brandtia smaragdina, T. Stebbiiig 

 in: Tr. Linn. Soc. London, ser. 2 r. 7 p. 424. 



Shows some affinity to CardiophiliiiS (p. 395). Sexual Variation very marked. 

 Body stouter in 9 than in d . JVfedian carina on peraeon Segments H and 7 and 

 pleon Segments 1 — 3 consisting of long tubercles of little prominence; pleon 

 Segments 4—6 caming 2 or 3 little groups of very delicate spines; marginal 

 carinae not raentioued. Head, rostrum rounded, depressed. Side-plates 1 — 4 

 with marginal setae. F]yes convex, reniforra, black. Antenna 1 in d as long 

 as body, 4 times as long as antenna 2. in 9 half as long as body, twice 

 as long as antenna 2, 1^* Joint stout, flagellum in d with 44, in 9 with 

 34 joints. Antenna 2, flagellum 8-jointed. Gnathopods 1 and 2, 6*'» Joint 

 oval, in d that of gnathopod 1 somewhat the larger. Peraeopods 3—5, 

 2*^ Joint moderately broad, most expanded in peraeopod o, with bind margin 

 and surface setiferous and margin also spinöse, üropod 3 short, longer in 

 d than in 9, outer ramus ^4 — ^!ä longer than inner, in d with plumose 

 setae on inner margin, on outer and apex with spines and simple setae; in 

 9 with 2 spines on outer margin, on inner with 2 or 3 setae, at apex with 

 spines and setae, inner ramus caming only setae. Telson divided. Colour 

 emerald-green {var. intermedins whitish; it has in 9 smaller eyes, shorter 

 antennae, and shows some minute differences in the uropod 3). L. 11 — 12 mm. 



Lake Baikal. Depth 50 — 100 m (var. intermedius at 15 ni). 



6. B. fasciata Stebb. 1874 Gammarus zehra (non Rathke 1843!), B. Dybowsky 

 in: Horae Soc. ent. Boss., v. 10 suppl. ]>. 166 1. 14 f. 7 1893 Atylus? z., A. Della Valle 

 in: F. Fl. Neapel, i'. 20 p. 931 | 1899 Brandtia fasciata, T. Stebbing in: Tr. Linn. Soc. 

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



Peraeon Segments 5 — 7 or 6 and 7 and pleon segments 1 — 3 carinate 

 or provided with little tubercles in the median dorsal line ; pleon segments 4 — 6 

 very convex, with very delicate spine-points or setae. Head, rosti-um short, 

 slightly depressed. Side-plates 1 — 4 scantily setiferous. Eyes reuiform, black. 

 Antenna 1 very little longer than antenna 2. \—';', as long as body, 1^* Joint 

 rather broad, slightly flattened, flagellum 10 — 13-jointed. xlntenna 2, flagellum 

 5 — 7-jointed. Gnathopods 1 a.nd 2 subequal, 6*'* Joint oblong, palm shorter 

 and less oblique in gnathopod 2. Peraeopod 5, 2'^ Joint ti-apezoidal, with the 

 Corners rounded, liroadest below, much lu'oader and longer than the coiTesponding 

 Joint of peraeopods 3 and 4. Uropod 3 short, outer ramus with small 2*^ Joint, 

 in leng-th about 4 times as long as the inner ramus, with 4 spines and several 

 setae on outer margin, simple setae on the inner, spines and setae at the 

 apex, the inner ramus with 1 long apical seta. Telson divided. Colour greenish 

 brown, with dark brown or black stripe across each segment. L. 17 mm. 



Lake Baikal. At river montlis, asceiiding the streams in swarms. 



19. Gen. Micmropus Stebb. 



1899 Micruropus, T. Stebbing in: Tr. Linn. Soc. London, ser. 2 «. 7 p. 424. 



Without carinae or overarching segments. Antennae 1 and 2 short; 

 antenna 1 usually longer than antenna 2, the peduncles not greatly diifering 



