CRUSTACEA MALACOSTRACA. III. 65 



convex; each postero-lateral angle is produced in a small, quite low protuberance terminating in a 

 very short spine marked off by an articulation; the posterior part of the abdomen between the uropods 

 is produced into a rather large triangle much broader than long, and its terminal, subacute angle is 

 about ioo°. — The operculum (fig. 4 f) is slightly longer than broad, with the proximal margin very 

 convex, while its distal margin is long and very feebly convex. - - The uropods, inserted between this 

 plate and the lateral protuberances, are more than twice as long as broad, subacute, and feebly over- 

 reaching the median triangle. 



Length of the younger specimen without head and the two anterior segments 2-5 mm.; as the 

 lost parts have probably measured o-6 mm., the entire animal, which has the seventh pair of legs 

 scarcely developed to full relative size, has consequently been about 3-1 mm. long. The specimen, of 

 which only the anterior segments with head remain, has certainly measured about 4*3 mm. 



Remarks. It seems to me very improbable, but yet not completely impossible, that some 

 future zoologists possessing a good material may find that the two mutilated specimens referred here 

 to the same species in reality belong to two different species; in that case the name //. tenuispinis 

 ought to be applied to the form, of which the head and the anterior thoracic segments are described 

 here. The species is abundantly distinguished from the other forms. 



Occurrence. Taken by the "Ingolf" at two deep stations in the warm area. 



Davis Strait: Stat. 24: Lat. 63°o6' N., Long. 56°oo' W., 1199 fath., temp. 2-4°; anterior part of a spec. 



South of Davis Strait: Stat. 22: Lat. 58°io' N., Long. 48°25' W., 1845 fath., temp. 1-4°; 1 spec. 



without head, etc. 



40. Haplomesus modestus u. sp. 



(P1.V, figs. 5 a- 5 b). 



Female. Only an immature, extremely mutilated specimen, without head and first thoracic 

 segment, is to hand. 



Third thoracic segment (fig. 5 a) with a pair of small, acute processes originating at the lateral 

 margins and directed mainly forwards; second segment shows mutilated rudiments of probably similar 

 processes; fourth segment with a pair of nearly similar processes placed dorsally near the lateral 

 margins. Fifth segment about six and a half times as long as broad somewhat before the middle; its 

 widened terminal part much narrower than the anterior segments. 



Abdomen with the proximal part about as long as broad, considerably shorter than the posterior 

 part or segment, divided besides by a feeble lateral constriction into two parts or segments, and marked 

 off from last thoracic segment by a feeble constriction and dorsal impression, from the last abdominal 

 segment by a feeble constriction. The posterior segment about as long as broad, increasing distinctly 

 in breadth backwards, with the postero-lateral corners rectangular and each terminating in a small, 

 thick, articulated spine (fig. 5 b). The posterior margin between the sublateral uropods about semi- 

 circular. — The operculum slightly broader than long, but otherwise nearly as in the preceding form, 

 having the basal margin strongly convex and the posterior margin long and very feebly convex. - 

 The uropods somewhat smaller than in H. tenuispinis, but showing about the same shape. 



Length of the fragment described r8 mm.; the animal has been slightly more than 2 mm. long. 



The Ingolf-Expedition. III. s- 9 



