5l4 Gammaridarum species incertae sedis. Dexaminidae, Dexamine 



G. sp., Risso 1826 G. marinus (non Leach 1815!), A. Risso, Hist. nat. Eur. 

 nierid., v.6 p. 96 | 1888 Gr. m., T. Stebbing in: Rep. Voy. Challenger, v. 29 p. 128. 



Colour intense grey, with deep grey dots, antennae and legs paler. 



Mediterranean. 



31. Farn. Dexaminidae 



1813/14 Dexamerülae, Leach in: Edinb. Enc, v.7 p. 432 | 1876 Subfam. Dex- 

 aminae, A. Boeck, Skand. Arkt. Amphip., v. 2 p. 310 j 1888 Dexaminidae, T. Stebbing 

 in: Rep. Voy. Challenger, v.29 p. 573, 900 | 1893 Dexaminidi (part.), A. Della Valle in: 

 F. Fl. Neapel, v. 20 p. 556. 



Pleon Segments 5 and 6 coalesced. Antenna 1 with long 2* Joint, 

 without accessory flagellum. Upper lip rounded. Lower lip varying. Mandible 

 (Fig. 90 p, 520) without palp. Maxiila 1 varyiüg, inner plate with only 1 

 er 2 setae or setules. Maxilla 2, inner plate the smaller, not fringed on 

 inner margin. Maxillipeds (Fig. 92 p. 522), outer plates very long, palp 

 rather short, finger small or wanting. Gnathopods 1 and 2 feeble, sub- 

 chelate. Peraeopods 1 — 5, fingers of all commonly pointing backward, üropod 3, 

 rami subequal, extending beyond uropod 2. Telson elongate, deeply cleft. 



Marine. 



5 genera, 10 accepted species and 5 doubtful. 



Synopsis of genera: 



{Maxillipeds, palp 3-jointed; lower lip with 

 inner lobes rudimentary — 2. 

 Maxillipeds (Fig. 92), palp 4-jointed; lower lip 

 with inner lobes well developed — 3. 



{Peraeopods 1—5, 4th Joint shorter than öth 

 and 6tli combined 1. Gen. Dexamine . . . p. 514 

 Peraeopods 1 — 5, 4tli Joint longer than 5tli 

 and Qth combined 2. Gen. Tritaeta . . . . p. 517 



f Maxilla 1, palp 1-jointed 3. Gen. Paradexamine . p. 518 



\ Maxilla 1, palp 2-jointed — 4. 



f Maxilla 1, 2d Joint of palp large; maxillipeds, 



inner plates well developed 4. Gen. Polyeheria . . p. 519 



Maxilla 1, 2^ Joint of palp small; maxillipeds 



(Fig. 92), inner plates rudimentary .... 5. Gen. Guernea. . . . p. 521 



4 



1. Gen. Dexamine Leach 



1813/14 Dexamine (Sp. un. : D. spinosa), Leach in: Edinb. Enc, v.7 p. 432 | 

 1888 D., T. Stebbing in : Rep. Voy. Challenger, 'v. 29 p. 945 | 1893 D. (part.), A. Della 

 Valle in: F. Fl. Neapel, t?. 20 p. 572 | 1894 D., G. 0. Sars, Crust. Norway, v.l p.473 | 

 1846 Dexamene, L. Agassiz, Nomencl. zool., Index p. 121 [ 1851 Amphithoiiotus (part.), 

 (A. Costa in:) F. W. Hope, Cat. Crost. Ital., p. 45 ] 1861 Amphitonotus, E. Grube, Ausfl. 

 Triest, p. 136. 



Body rather stout in 9 ; some segments with dorsal projections. Head, 

 rostral projection veiy small, post-antennal corners obsolete. Side-plates of 

 moderate size. Antenna 1 with long peduncle, in 9 longer than antenna 2. 



