56 



Distribution. — Greenland (Kroyer), the Kara Sea (Hansen), St. 223 & 

 290 of the Norwegian North Atlantic Expedition. 



4. Gnathia abyssorum, G. 0. Sars. 



(PI. XXIII, fig. 2.) 

 Anceus abyssorum, G. 0. Sars, TJndersagelser over Hai'dangerfjordens Fauna, Crustacea, p. 34. 



Specific Characters. — Male: Body very short and stout, subclavate in 

 form, with the posterior division of mesosome somewhat narrower than the an- 

 terior, both being defined by a well-marked constriction. Cephalosome exceedingly 

 large, rounded quadrangular in shape, with the supra-ocular processes well-defined 

 and coarsely denticulate, dorsal face, like that of the anterior part of mesosome, 

 clothed with small spinules and scattered hairs. Penultimate pedigerous segment 

 divided dorsally into 2 lateral arese by a rather broad median, soft-skinned space, 

 last segment considerably narrower, with the lateral corners obtusely produced. 

 Metasome comparatively short, with simple, rounded epimera. Eyes unusually large, 

 with light yellowish pigment. Mandibles powerfully developed, and pronouncedly 

 securiform in shape, outer edge perfectly smooth, without any notch, inner, pro- 

 duced at the base to a large, obtusely conic expansion, tip pointed. Pereiopoda 

 coarsely spinous inside. Terminal segment of metasome abruptly contracted in 

 its outer part, which is narrowly conic in form. Uropoda with the rami compara- 

 tively-narrow. — lemale: Body fusiform, with the 3 posterior, pedigerous segments 

 well defined, and forming together an oval division, two and a . half times as 

 long as that preceding it. Cephalosome triangular, front rather produced, and bi- 

 dentate at the tip. Pleopoda in both sexes not natatory, rami narrow sacciform, the 

 outer one considerably shorter than the inner. Colour of male bluish white, of 

 female whitish pellucid, without pigmentary spots. Length in both sexes about 3 mm. 



Remarks. — This form was at first observed by the present author only 

 in the female sex; but subsequently I have also succeeded in finding the male, 

 and am thus enabled to draw up a complete diagnosis of the species. The dis- 

 covery of the male has shown this species to be very nearly allied to the form 

 described by the present author from' the Norwegian North Atlantic Expedition 

 as Anceus robustus; but the present species is of much inferior size, and of a 

 still shorter and more compact form, differing, moreover, in the shape of the 

 mandibles, and in the larger size of the eyes. By the 2 latter characters, it is 

 also easily distinguishable from the 3 other Norwegian species. 



Occurrence. — A single female specimen of this form was first taken in 

 the inner part of the Hardanger Fjord, at TJtne, from the considerable depth of 



