74 



Bemarls. — Tins new genus is nearly related to the genus Ordiomene, 

 though differing materially by the epistome being not at all prominent, by the 

 very powerful structure of the anterior gnatho2)oda, and b}^ the much fuller 

 development of the last pair of urojioda and of the telson, fiually by the un- 

 anned last pair of epimeral plates of tlie metasome. In the structure of the 

 oral pai'ts it comes somewhat nearerto the genus Orchomenella. Besides the noi'them 

 species described iu the sequel, 2 of the Challenger sjiecies referred by the Rev. 

 Mr. Stebbing to the genus Orchoniene, viz., 0. mnsculosus and O.ahijssorum, eyidently 

 belong to the present genus and perhaps also his 3rd, sjjecies, 0. excavatus. 



28. Orchomenopsis obtusa, G. 0. Sars, n. sp. 



(PI. 20, fig, 2.) 



Body moderately slender with broadly rounded back. Cephalon about 

 as long as the 1st segment of mesosome, lateral corners but slightly projecting 

 and broadly rounded. Anterior coxal plates about twice as deep as the body; 

 1st pair gradually widening below; 4th pair distinctly emarginated posteriorly 

 and fonning below the emargination an obtitse projecting lobe ; 5th pair fully 

 as deejo as broad. Last pair of epimei-al plates of metasome not at all pro- 

 jectiiag at the infero-lateral corners, the edge forming an even uninterrupted 

 ciu've. First segment of urosome deeply impressed at the base dorsally and 

 forming below the depression a rounded carina. Eyes rather large, irregularly 

 oval, pigment ligth red. Siiperior antennae with the 1st joint of the peduncle 

 very large and thick; Hagellum of moderate length, 10-articulate, 1st joint 

 large, about as long as the 5 succeeding joints combined; accessory appendage 

 aboiit half the length of the flagellum and 5-articulate, 1st joint as long as 

 the remainder part of the appendage. Inferior antenna? rather slender, exceed- 

 ing the superior by about half their length; flagellum composed of about 18 

 articulations. Anterior gnathopoda very strong, propodos twice the length of 

 the carpus and but veiy slightly tapering to the transversely truncated ex- 

 ti'emity, carpiis exhibiting below a rounded projecting lobe. Posterior gnatho- 

 poda with the carpus rather broad, bulging out interiorly, propodos aboiit 

 half its length, widening distally, with the upper edge ciu-ved, the lower 

 straight. Pereiopoda rather elongated but powerful in structure, basal joint 

 of the 3 posterior pairs much shorter than the remainder part of the leg. 

 Last pair of uropoda with tlie inner ramus very little shorter than the outer; 

 terminal joint of the latter very small. Telson about twice as long as broad 

 at the base, regularly tapering distally, ^vith 4 or 5 pairs of dorsal denticles 

 near the edges and 2 other pairs inside the others; cleft extending somewhat 



