450 Pherusa, Xiphargoides 



large, curved, sometimes overlapping the whole length of the band, but 

 sborter in young d. Peraeopods 1 and 2, 4*^ Joint scarcely dilated, longer 

 tban 5*^ 5*^ tban 6*^ Peraeopods 3 and 4, 2*^ Joint moderately expanded, 

 more above tban below. Peraeopod 5, 2^ Joint very wide at the middle. 

 Pleopods witb many coupling spines on tbe peduncle. üropods 1 — 3 reacbing 

 about equally far back, üropod 3, outer ramus seemingly witb miuute 2"^ Joint, 

 inner scarcely balf as long or balf as wide as outer. Telson subquadrate, 

 cleft about '74 of lengtb, witb spinule in eacb rounded apex. Colour yellowish 

 brown. L. 7— 1 2 (?) mm. 



North- Atlantic (South-England, shore atvery low tides; Channel Islands; Scotland, 

 Firth of Clyde; France; Azores); Mediterranean ; ßlrtck Sea. Down to 84 m. 



39. Gen. Niphargoides 0. Sars 



1894 Niphargoides (Sp. typ.: X. caspius), G. 0. Sars in: Bull. Ac. St.-Petersb., 

 ser. 5 «. 1 p. 371. 



Akin to Pontoporeia (p. 127) and Gammarus (p. 460) ratber tban Niphargus 

 (p. 405). Body nearly smootb, robust. Head not rostrate. Side-plates 1—4 

 Qot veiy large, setiferous, 4*^ the largest, excavate behind. Antennae 1 and 

 2 Short, subequal; antenna 1 witb accessory flagellum usually more tban 

 l-jointed. Lower lip witb inner lobes. Mandibular palp large. Maxillipeds, 

 3^ Joint of palp slender. Moutb-pai-ts otherwise as in Gammarus. Gnatbo- 

 pods 1 and 2 well developed, subcbelate, 2^ usually tbe sti-onger. Peraeopod 5, 

 2^ Joint much more expanded tban in peraeopods 3 and 4, bind margin, 

 like the peraeopods in general, strongly setiferous. üropods 1 and 2 witb equal 

 rami. üropod 3 not very large, outer ramus much the larger, 2-jointed, 

 inner ramus scale-like. Telson cleft to the base. 



I 



7 species. 



Synopsis of species: 



üropod 3, 2d Joint of outer ramus rudimentary — 2. 

 1 \ üropod 3, 2d Joint of outer ramus distinctly 

 developed — 4. 



iGnathopods 1 and 2, 6*^1 Joint narrowing towards 

 the palm 1. N. caspius .... p. 450 

 Gnathopods 1 and 2, 6ttjoint not narrowing towards 

 the palm — 3. 



Gnathopods 1 and 2, hind margin longer than palm 2. N. corpulentus. . p. 451 

 Gnathopods 1 and 2, hind margin shorter than palm 3. ÜT. compactus . . p. 451 



/ Üropod 3, 2d Joint of outer ramus much shorter 



1 than inner ramus 4. N. grimmi . . . . p. 452 



M 



I ur 



than inner ramus — 5 



j üropod 3, 2d Joint of outer ramus not much shorter 



«{ 



f Lobes of telson strongly divergent 5. N. quadrimanus . p. 452 



\ Lobes of telson not strongly divergent — 6. 



Gnathopods 1 and 2 subequal 6. K". aequimanus . p. 453 



Gnathopod 1 considerably smaller than guathopod 2 7. N. borodini . . . p. 453 



1. N. caspius 0. Sars 1894 N. c. (Niphargus c. 0. Grimm in MS.), G. 0. Sars 

 in: Bull. Ac, St.-Petersb., ser. 5 u 1 p. 372 t. 16. 



Body ratber elongate, but robust and uncompressed, witb only 2 dorsal 

 spinules on pleon segment 6. Head, lateral lobes rounded, little prominent. 



