Gammarus 465 



reaching much beyoud the others, outer ramus long, with setae ou inner 

 margin, its '2^ Joint full}^ half as long as 1^*' and as long as the peduncle, 

 inner raraus shortev than peduncle, tipped with 2 spines. Telson much 

 longer than broad, tapering, each narrow lobe having 1 lateral and 1 apical 

 spinule. L. 6 mm. — ö not kuown. 



Caspian Sea. 



7. G. compressus 0. Sars 1894 G. c, G. O. Sars in: Bull. Ac. St.-Petersb.. 

 ser. 5 r. 1 p. 353 t. 11 f. 1-10. . 



9 . Body slender, much compressed, dorsally smooth except for pair 

 of minute spinules on pleon segraent 6. Head without rostrum, lateral lobes 

 narrowly rounded, little prominent. Side-plates 1 — 4 large, setulose, 1 ^'^ 

 widely expanded tbrvvard, 4*^ as broad as deep. Pleon segments 2 and 3, 

 postero-lateral corners subquadrate. Eyes not large, narrowly oblong, dark. 

 Antenna 1 scarcely more than ^/^ as long as body, V^ Joint massive, longer 

 tlian 2"^ and 3*^ combined, flagellum subequal to peduncle, 9-jointed, acgessory 

 flagellum 3-jointed. Antenna 2 subequal to antenna 1, ultimate Joint of peduncle 

 shorter than penultimate, flagellum subequal to peduncle, 6-jointed. Gnatho- 

 pods 1 and 2 rather small and feeble, palm short and nearly transverse, 5*'^ and 

 6^'' joints rather narrower and longer in gnathopod 2 than in gnathopod 1. 

 Peraeopods 1 and 2 strongly built, especially peraeopod 2, 4^^ Joint large, 

 expanded, 5*1^ oval, both densely fringed with setae on hind margin. Peraeo- 

 pods 3 — 5 subequal in length, 4*^ Joint rather broad, 2'^ Joint rounded oval 

 in peraeopod 3, narrower in peraeopod 4, with very sinuous hind margin, 

 much larger and oval in peraeopod 5, ending in a produced, rounded lobe. 

 Uropods 1 and 2, rami subequal, narrow, with spines only at apex. Üropod 3 

 of moderate size, reaching beyond the others, outer ramus about twice as 

 long as peduncle, 2'^ Joint about half as long as 1^*, inner ramus nearly 

 half as long as outer, tapering, tipped with a spine and 2 or 3 setules. 

 Telson fuUy as long as broad, lobes gradually diverging, each with 2 spines 

 at the somewhat truncated apex. L. 7 mm. — ö unknown. 



Caspian Sea. 



8. G. subnudus 0. Sars 1896 G. s., G. 0. Sars in: Bull. Ac. St.-Petersb., ser. 5 

 f. 4 p.451 t. 6 f. 11— 19. 



9 . Back broadly rounded, dorsally smooth except for a few small 

 hairs at end of pleon segments 4 — 6. Head, lateral lobes broad. obliquely 

 truncated, lower corner the more prominent. Side-plates 1 — 4 large, not 

 setose, 1^* not expanded distally, 4*^ broad. Pleon segments 2 and 3, 

 postero-lateral corners quadrate. I'lyes of medium size. oblong oval, dark. 

 Antenna 1 scarcely more than ^j.^ as long as body, 1^* Joint scarcely as long 

 as 2^ and 3'^ combined, flagellum subequal to peduncle, 16-joiuted, accessory 

 flagellum 3-jointed. Antenna 2 a little shorter, flagellum shorter than 

 ultimate and penultimate joints of peduncle. Gnathopod 1, 5*^ Joint short, 

 6*^ oblong oval, palm rather oblique, defining angle obtuse. Gnathopod 2 

 similar in shape, but 6*^ Joint more than twice as large as in gnathopod 1. 

 Peraeopods 1 — 5 not very slender, very scantily furnished with spines and 

 setae, 2'^ Joint in peraeopod 3 rounded quadrangular, in peraeopod 4 gradually 

 but greatly narrowing distally so as to have uo free corner, in peraeopod 5 

 large, oval, with rounded lobe much produced downward. üropod 3 of 

 moderate size, but reaching much beyond the others, outer ramus broad, 

 about twice as long as peduncle, fringed with setae, 2^ Joint small but distinct, 



Das Tierreich. 21. Lief.: T. R. R. Stebbing, Ampliipoda I. 30 



