516 Dexamine 



lobe, 4*^ Joint subfusiform, much broader and longer tban 5*^ Peraeopod 4, 

 2^ Joint piriform, abruptly narrowed below, 4**^ as long as 5*i*. Peraeopod 5 

 rather shorter, 2"* Joint oval, narrowest below, 4*^ shorter than 5*^^'. Branchial 

 vesicles pleated, Uropod 3, rami about twice as long as peduncle. Telson 

 thrice as long as broad, cleft to ^^ length, each half witb 3 lateral spines 

 and 1 on obtuse apex. Colour a mixture of chestnut-brown, pink, light j^ellow 

 and pure white (Sars), sometimes brilliant with mingled green and red. 

 L. 9 reaching 14 mm, ö rather smaller. 



Arctic Ocean, North- Atlantic with adjoining seas (Europe from Vadsö to the 

 Black Sea; Azores). Within tide-marks to 75 m. 



2. D. thea Boeck 1861 D. t., A. Boeck in: Forh. Skand. Naturf., Made 8 p. 658 | 

 1876 D.i., A. Boeck, Skand. Arkt. Amphip., v.2 p. 315 t. 12 f. 1 | 1885 D.i., J. S. 

 Schneider in: Norske Selsk. Skr., 1884 p. 20 t. 2 ] 1893 D. t, D. spinosa (part.)?, A. 

 Della Valle in: JF. Fl. Neapel, ».20 p. 579 | 1893 & 94 D. t, U. O. Sars, Crust. Norway, 

 v.l t. 168 f. 1; p.477 [ 1862 D. tenuicornis (err., non AmpJiithoe t H. Rathke 1843!), 

 Bäte & Westwood, Brit. sess. Crust., v.l p. 240 f. | 1871 D. heibergi, A. Boeck in: Forh. 

 Selsk. Christian., 1870 p. 187 | 1876 D. h., A. Boeck, Skand. Arkt. Amphip., p. 316 

 1. 12 f. 3. 



Peraeon, pleon and head nearly as in D. spinosa (p. 515), but eyes smaller, 

 oval. Antenna 1, 1^* Joint not apically produced, 3*^ Joint not extremely short, 

 flagellum 16-jointed. Antenna 2 in 9 much shorter, ultimate Joint of peduncle 

 subequal to penultimate (Sars) or shorter than it (Schneider), flagellum little 

 longer than peduncle, 11-jointed. Gnathopods 1 and 2 and peraeopods 1 and 2 

 nearly as in D. spinosa. Peraeopod 3, 2^ Joint with hinder margin and lower 

 lobe subangular, 4*^ much longer and broader than 5*^, 5*'^ slightly shorter than 

 Qt\ Peraeopod 4, 2^ Joint little louger than broad, very convex behind, and 

 finely serrate, 4*^ longer than 5*^ 5*^^ than 6*^ Peraeopod 5, 2"^ Joint almost 

 linear, 5^^ longer than 4*^ or 6*^, finger strong in this and the other peraeopods. 

 Branchial vesicles simple, üropod 3, rami twice as long as peduncle, rather 

 narrow. Telson not quite thrice as long as broad, cleft nearly to the base, 

 spines as in D. spinosa, with addition of 2 subdorsal pairs. Colour yellowish, 

 semipellucid, mottled with brown and pink. L. 4 — 6 mm. 



Arctic Ocean, North-Atlantic, North-Sea and Skagerrak (from Vadsö to Christiania- 

 fjord; north of Great Britain; France); Kattegat. Depth to 113 m. 



3. D. spiniventris (A.Costa) 1853 Amphithonotus s., A. Costa in: Rend. Soc. 

 Borbon., n. ser. v. 2 p. 173 | 1857 A. s., A. Costa in: Mem. Acc. Napoli, v. 1 p. 186 t. 2 

 f. 1 I 1864 Dexamine s., E.Grube in: Arch. Naturg., ».30i p. 195 | 1866 D.s., Cam. 

 Heller in: Denk. Ak. Wien, ». 26n p. 30 | 1893 D. spinosa (part.), A. Della Valle in: 

 F. Fl. Neapel, v. 20 p. 573 t. 5 f. 9; 1. 18 f. 18. 



Pleon moderately robust, pleon segments 1 — 4 and 6 carinate, each 

 produced to a dorsal tooth, in segment 4 and sometimes in 3 preceded by 

 a smaller tooth, segments 1 — 3 and 6 having a pair of latero-dorsal ridges 

 ending in smali teeth, sometimes obsolete on segment 1, the part of the coalesced 

 segment corresponding to segment 5 separated as usual from segment 6 by 

 a depression. Head, rostrum very short, lateral corners angular. Pleon 

 segment 3, postero-lateral corners sharply produced. Eyes reniform, not verj^ 

 large. Antenna 1, 1^* Joint produced to a sharp tooth, 2'^ less than double 

 as long as P* (Della Valle; Heller: thrice), flagellum 40— 50-jointed. Antenna 2 

 shorter (at least in Q ), ultimate Joint of peduncle longer than penultimate, 

 flagellum about 40-jointed. Gnathopods 1 and 2 and peraeopods 1 — 5, uropods 

 and telson much as in D. spinosa (p. 515). Colour dull yellow. L. !■ — 8 mm. 



Mediterranean. 



