CRUSTACEA MALACOSTRACA. III. 



II 7 



considerably outwards. — First thoracic segment narrower and somewhat longer than the second, 

 which is scarcely as long as the fourth. Epimera well developed but not produced, having the margin 

 of their anterior section evenly convex. Fifth segment considerably broader than long, subrectangular, 

 with the lateral margins nearly parallel and all angles rounded. 



First pair of legs (fig. 3 c) very robust. Fifth joint only half as long again as deep, with a 

 single very strong spine beyond the middle of the lower margin, a strong seta near the distal end, 

 and on the angle a very robust spine, which is as long as the joint. Sixth joint very large, consider- 

 ably longer than the fifth, somewhat less than three times as long as deep. — Second pair of legs 

 (fig. 3 d) uncommonly robust; fourth joint on the distal lower angle with a very thick spine slightly 

 longer than the joint; fifth joint about twice as long as deep, with five or four spines along the lower 

 margin and the end; the spines increase gradually and strongly in length from the first to the last, 

 and if five are present the first is small, the others very strong; the two distal are distinctly curved, 

 and the most distal, which is placed just above the angle, is as long as the sixth joint; the upper 

 margin with three strong setae. Sixth joint with three strong setae on the upper and two on the lower 

 margin. — Seventh pair (fig. 3 c) rather slender; fifth joint with five setse on the lower margin and 

 three of them extremely long; sixth joint with two setae below. 



Abdomen somewhat longer than broad, decreasing conspicuously in breadth from somewhat 

 from the base to near the postero-lateral teeth, which are somewhat slender and situated rather far 

 in front of the end of abdomen, as the posterior margin is extremely convex. — Uropods considerably 

 less than half as long as the abdomen, rather remote from the median line; exopod between one-third 

 and half as long as the endopod. 



Length of the largest specimen, a female without marsupium, 2 mm.; a female with marsupium 

 from Skager Rak is r8 mm. 



Remarks. Specimens of this species had been separated by me among the "Ingolf" material 

 and among material from Skager Rak, and I named them D. laterale. The three specimens from the 

 last-named place were later handed over to G. O. Sars, who described and figured the species as Eu- 

 gerda lateralis. But as Sars has overlooked the processes from the sides of the head, and as his figure 

 of the entire animal is not as correct in some few particulars as usually is the case, I have drawn 

 five figures and redescribed the species. 



It may be pointed out that D. laterale is instantly distinguished from all other species of Des- 

 mosoma by the outstanding processes on the sides of the head, and by the armature of first pair of 

 legs. In females without marsupium each of the four anterior segments has a long, subvertical spine 

 in the median line of the ventral surface. 



Occurrence. Taken by the "Ingolf" at a single station in the warm area. 



Davis Strait: Stat. 25: Lat. 63°3o' N., Long. 54°25' W., 582 fath., temp. 3-3°; 6 spec. (?). 



Distribution. The only earlier known locality is in Skager Rak, 15 sea-miles from the 

 lighthouse of the Skaw, 125 fath., ooze. 



