351 



5. Pa ramp hit hoe monocuspis, G. 0. Sars, n. sp. 



(PL 123, fig. 2). 



Very like the preceding species, though perhaps somewhat more robust 

 of form, and having only a single small dorsal projection issuing from the 

 2nd segment of metasome. Cephalon nearly as in that species, except that 

 the postantennal corners are considerably more produced and spiniform. First 

 pair of coxal plates comparatively much broader than in P. bicuspis, and 

 distinctly expanded distally, with a small dentiform projection at the infero- 

 posteal corners; the 2 succeeding pairs likewise comparatively broader, and 

 scarcely tapering distally; 4th pair but little deeper than the corresponding 

 segment, and having the posterior projection short and obtuse. Last pair of 

 epimeral plates of metasome produced at the lateral corners to a dentiform 

 projection, which however is not defined above by any distinct sinus. Eyes 

 somewhat larger than in P. bicuspis and more regularly oval in form, pigment 

 dark red. Antennae nearly as in that species, except that the basal joint of 

 the superior antennae is somewhat shorter and stouter, scarcely exceeding in 

 length the 2 succeeding joints combined. Gnathopoda likewise of a very 

 similar structure, but comparatively stouter, with the propodos broader in 

 proportion to its length. Pereiopoda rather strong, the 3 posterior pairs suc- 

 cessively increasing in length. Last pair of uropoda with the outer ramus con- 

 siderably exceeding half the length of the inner. Telson oval in form, not 

 nearly twice as long as it is broad, tip evenly rounded. Body whitish, but 

 very sparingly mottled with brown pigment, except in the anterior part of 

 the cephalon and the peduncles of the antennae, which are very darkly coloured. 

 Length of adult female 11 mm. 



Remarks. - I have formerly regarded this form as only a variety of P. 

 bicHSpis, with which species it is in fact closely allied. On the closer anato- 

 mical examination of both forms subsequently instituted, I have, however, 

 found it to differ, not only in the absolute want of the anterior dorsal 

 projection, but also in a few other points mentioned in the above diagnosis, 

 and I have therefore found it necessary to keep it apart as a distinct spe- 

 cies. Among some specimens of P. bicnspis from Greenland, kindly sent to 

 me for examination by Dr. Hansen, there was a single specimen of this 

 form, perfectly agreeing with the Norwegian specimens. 



Occurrence. - - Some specimens of the present species were collected 

 by the author, many years ago, at Hammerfest, Finmark, from a depth of 

 30 to 50 fathoms, among Hydroidse. This is the only place off the Norwegian 

 coast, where it has as yet occurred. 



Distribution. Greenland (the author). - 



