245 



palps, moreover, in the form of the posterior lip, and the somewhat unequal 

 development of the 2 anterior pairs of pereiopoda. From both these genera 

 it differs by the deviating form of the basal lobes of the maxillipeds, and 

 especially by the very strongly-pronounced sexual difference as regards the 

 structure of the posterior gnathopoda. The genus Probolhim of Costa was identified 

 by Boeck and most subsequent authors, with the genus Stcnothoe. This, I 

 believe, is not correct. For to judge from the figure given by Costa of the 

 species upon which his genus was founded, P. polyprion, this form is scarcely 

 a Stcnothoe in the sense of Boeck, but most probably congeneric with the 2 

 Norwegian species to be next described. 



7. Probolium gregarium. G-. 0. Sars. 



(PI. 84). 

 Metopa gregaria, G. O. Sars, Overs, af Norges Crustaceer I, p. 93, PI. 4, fig. 6. 



Body rather stout, and somewhat compressed, with evenly rounded 

 back. Cephalon about twice as long as the 1st segment of mesosome, lateral 

 corners nearly rectangular, front scarcely produced. Second pair of coxal 

 plates nearly of equal breadth throughout, and broadly rounded at the tip, 

 posterior edge slightly sinuated, 3rd pair rather expanded distally, especially 

 in the male, and fully twice as deep as the corresponding segment; 4th 

 pair about as large as the 2 preceding pairs combined, obtusely produced 

 posteriorly, and having the distal edge evenly curved. Last pair of 

 epimeral plates of metasome somewhat produced at the lateral corners. 

 Eyes of moderate size, rounded oval, with well-developed visual elements 

 and dark red pigment. Superior antennae scarcely exceeding half the length 

 of the body, and rather slender, 1st joint of the peduncle about as long as 

 the cephalon, 2nd joint of same length, but much narrower, flagellum half 

 as long again as the peduncle. Inferior antennae with the last joint of the 

 peduncle a little shorter than the penultimate one, flagellum not attaining 

 half the length of the peduncle. Anterior gnathopoda with the meral joint 

 produced at the end inferiorly to a rather projecting setiferous process, 

 propodos about the length of the carpus, and scarcely broader, its inferior 

 edge slightly curved in the middle, and armed, in addition to the bristles, 

 with 4 small spinules. Posterior gnathopoda in female more than twice as 

 large as the anterior, propodos fully as long as the basal joint, and 

 oblong oval in form, palm rather oblique, and somewhat longer than the hind 

 margin, from which it is defined by a distinct angle, armed with a small 



31 Crustacea. 



