476 Gammariis 



011 iimer inargin. Telsoii much longer than broad, lobes eacli with 2 long 

 spines and some long setae on the apex, which is obliquely truncate from 

 within: higher np are .2 fascicles of setae. L. o 10, ö reaching 19 nira. 



Syrin. Fresh wator. 



29. G. loeusta (L.) 1758 Cancer l, Linne, Syst. Nat., ed. 10 p. 634 [ 1775 

 Gammarus l., J. C. Eabricius, Syst. Ent., p. 418 | 1862 G. l., Bäte, Oat. Amphip. Brit. 

 Mus., p. 206 t. 36 f. 6 | 1889 G. l, A. M. Norman in: Ann. nat. Hist., ser. 6 r. 4 p. 137 

 t.l2 f. 11 I 1889 G.I., Hoek in: Tijdschr. Nederl. dierk.Ver., ser. 2 v.2 p.206 t. 7 f. 10"; 

 1. 10 f. 10, 10' ! 1893 G. l. (part.), A.Della Valle in : F. Fl. Neapel, u 20 p. 759 t. 2 f. 1 : t. 24 

 f. 20—34; t.45f. 1—11 1 1890 & 94 G.Z., G.O.Sars, Crust. Norway, «;. 1 1. 1 ; p.499 t.l76 f. 1 ' 

 1808 Cancer (G.) l; Montagu in: Tr. Linn. Soc. London, ».9 p. 92 t. 4 f . 1 | 1766 Oniscus 

 pulex {j)txrt.), Pallas, Mise, zool., p. 190 ; 1853 Gammarus p., Stimpson in: Smithson. Contr.. 

 ».6 nr. 5 p. 55 | 1820 G. arcticus (Leach in 3IS.). Scoresby, Account arct. Regions, r.l 

 p.541 t.l6 f. 14 ] 1821 & 24 G.horeus, E.Sabine in: W. E. Parry, J.Voy., Suppl. p. 51; 

 p.229 I 1830 G. orriatus, H. .Milne Edwards in: Ann. Sei. nat., r. 20 p. 367, 369 t. 10 

 f . 1 — 8 I 1851 G. sitchensis, F. Brandt in: Middendorif, Reise Sibirien, r. 2i p. 137 

 t. 6 f. 28a — c j 1855 G. mufatus, W. Liljeborg in: Vetcnsk. Ak. Handl., 1853 ]). 447. 



Pleon Segments 4 — 6 each with median dorsal elevation caiTving" 

 3 — 5 spinules, lateral groups well separated, each with 3 or 4 spinules. Head, 

 lateral lobes angularly produced. Side-plates 1 — 4 larger than in G. marinn.s 

 (p. 472), especially in g ; side-plate 4 nearly as broad as deep. Pleon segments 2 

 and 3, postero-lateral corners acutely produced. Eyes rather large, reniform, 

 Paip black with chalky white coating. Antenna 1 in 9 

 not quite half as long as body, in ö rather longer, 

 1^* Joint subequal to 2^ and 3^ combiued, flagellum 

 Outer piate --^-U/ J^fH twice as long as peduncle, accessory flagellum about 

 Inner piate -^1 j \\j 8-jointed. Antenna 2 shorter, flagellum about as long as 



ultimate and penultimate joints of peduncle combinod. 



with calceoli in d. Gnathopods 1 and 2 in 9 , 6*'' Joint 



Fig. 87. Fig. 88. oblong, in gnathopod 2 longer and narrower. Guatho- 



Fjg. 87&88. G. loeusta. pod 1 in c?, ß^^joint piriform; gnathopod 2, 6**^ Joint 



[After^H^^j.^ Hansen.] much more powerful, irregularly oblong, palm oblique 



though less so than in gnathopod 1, in both with strong 



spine at centre. Peraeopods 3—5 rather slender and elongate, 2*^ Joint in peraeo- 



pod 3 forming a free corner, which is produced to an acute point. üropod 3 



elongate, rami fringed with plumose setae and several spines, inner ramus nearly 



equal to l*** Joint of outer. Telson longer than broad, each lobe with 3 apical spines 



and a seta. a spine and seta near the apex, and near the base 2 or 3 spines 



and one or two setae. Colour more or less dark brownish gi'een, with pinkish 



mark on sides of pleon segments 1—3. L. ö 20 — (arctic specimens) 48 mm, 



2 usually considerably smaller. 



Arctic Ocean, North- Atlantic with adjoining seas (East of United States of America,. 

 Europe). From shore to 100 m. 



30. G. eamylops Leach 1813/14 G. c, Leach in: Edinb. Enc, v.l p.403 | 1815 

 G. campylops, Leach in: Tr. Linn. Soc. London, f. 11 p. 360 | 1862 G. c, Bäte & Westwood, 

 Brit. sess. Crust., c. 1 p. 375 f. | 1894 G. c, G. O. Sars, Crust. Norway, v. l p. 500 t. 176- 

 f. 2 j 1819 G. camptolops, (Leach in:) Samouelle, Ent. Compend., p. 104 j 1862 G. c, Bäte, 

 Cat. Amphip. Brit. Mus., p. 209 t. 37 f. 3 | 1830 G. camphylops, H. Milne Edwards in: 

 Ann. Sei. nat., v. 20 p. 367. 



Pleon segments 4 — 6 each with 2 median dorsal spinules and 2 on 

 each side. Head, lateral lobes rather obliquely truncate, with very small 



