84 Orchomenopsis 



apically. Maxillipeds, outer plates oval, with little nodulous teeth on inner 

 mai'giu. length of plates compared with joints of palp a little variable. Gnatho- 

 pod 1 powerful, subchelate, 6*'^ Joint considerably longer than 5*'\ palra transverse, 

 well defiued. Gnathopod 2. 5*^» Joint rather expanded, 6*^^** nan-ower, about 

 half length of 5^^^ Peraeopods strong, 2'^ Joint of peraeopods 3 — 5 moderately 

 expanded, narrowed below. Uropod 3, rami projectiug beyond uropod 2, 

 setiferous. Telson niore or less tapering and more or less deeply cleft. 



4 species. 



Synopsis of species: 



Clel't of telson not t 

 Cleft of telson exten 

 / Gnathopod 2 minutely chelate 2. O. abyssorum . p. 84 



I Cleft of telson not qiiite reaching the centre . ... 1. O. musculosa . p. 84 

 \ Cleft of telson extending beyond the centre — 2. 



2 



\ Gnathopod 2 subchelate — 3. 



I Cleft of telson not dehiscent 3. O. obtusa . . . p. 85 



) Cleft of telson dehiscent 4. O. zschauii . . p. 85 



1. O. musculosa (Stebb.) 1888 Orchomene musculosiis, T. Stebbing in: Rep. 

 Voy. Challenger, v. 29 j). 673 t. 20 | 1891 0. m., Orchomenopsis (part.), G. 0. Sars. Crust. 

 Norvvay, v.l p. 74 | 1893 Anonyx m., A. Della Valle in: F. FI. Neapel, i;. 20 j). 823. 



Side-plate 5 deeper behind than in front. Pleon segnient 3, postero-lateral 

 angles much rounded. Antenna 1, flagellum with 11 joints. P* large, accessory 

 flagellum with 4 joints, 1**^ long. Antenna 2, ultiniate and peuultiraate joints 

 of peduncle subequal, flagellum with 13 joints. Maxilla 1, one palp with 11, 

 the other with 8 spine-teeth. Maxillipeds, inner plates with apical margin 

 excavate, outer plates reaching beyond 2*^ Joint of palp, with 2 spine-teeth on 

 apical margin. Gnathopod 1, 2*^ Joint short and massive, not longer than 5*'' and 

 6*'> combined, ö*'» short, cup-shaped, 6*'» oblong, thickest near base, bind margin 

 slightly coucave. palm transverse, with accurately titting finger. Gnathopod 2, 

 6*^^ Joint very little apically produced. Uropod 3, rami nearly equal. Telson twice 

 as long as broad, with a pair of dorsal and a pair of apical spinules, cleft 

 not quite reaching centre, slightly dehiscent throughout. L. about 12 mm. 



North-Pacific (South of Japan). Surface. 



2. O. abyssorum (Stebb.) yiSßS Anonyx chilensis, Cam. Heller in: Reise 

 Novara, v. 2iii Crust. p. 129 t. 11 f. 5 | 1888 Orchomene abyssorum, T. Stebbing in: 

 Rep. Voy. Challenger, tj. 29 p. 676 t. 21 | 1891 0. a., Orchomenopsis (part.). G. O. Sars, 

 Crust. Norway, vA p. 74 | 1893 Anonyx a., A. Della Valle in: F. Fl. Neapel, v.'20 i).824. 



Side-plate 5 not deeper behind than in front. Pleon segment 3, postero- 

 lateral angles slightly rounded. Antenna 1 similar to tliat of 0. musculosa. 

 Antenna 2, ultimate Joint of peduncle shorter than penultimate, equal to 

 antepenultimate, flagellum with 15 joints. Mandible, 2*^ Joint of palp longer 

 than in 0. musculosa. but mouth-organs of the two species in close agreement. 

 Gnathopod 1 similar to that of 0, musculosa, but of slighter construction, the 

 side-plate less expanded below, and the joints more slender. Gnathopod 2, tlie 

 slender 6*'» Joint strongly produced at apex to form a little chela with the 

 minute finger. Pleopods, coupling spines very small, yet with 3 retroverted 

 teeth below the terminal hook; 6 or 7 cleft spines on inner ramus (Fig. 14). 

 Uropod 3, outer ramus pretty distinctly longer than inner, Telson nearly 

 twice as long as broad, with 3 pairs of marginal and 1 of apical spinules, 

 cleft extending beyond the middle, dehiscent. L. about 9 mm. 



South-Atlantic (Buenos Ayres), depth 3578 m; South-Pacific (Chili)?. 



