78 CRUSTACEA MALACOSTRACA. II. 



Thoracic legs rather slender. Second and third pairs subsimilar (fig. 56); posterior spine on 

 fourth joint as long as fifth joint, which has two long distal spines; sixth joint about half as long 

 again as the fifth and somewhat longer than seventh with claw. Three posterior pairs (fig. 51) with 

 seventh joint only a little shorter than the sixth and its row of minute setiform denticles rather di- 

 stinct; claw somewhat long, longer than in the preceding forms. 



Five anterior abdominal segments feebly developed or scarcely distinct, the lower margin of 

 the segments being somewhat flatly convex (fig. 5 h). Pleopods with long setae. Uropods distinctly 

 longer than the two posterior segments combined and longer than in any other species of this genus 

 (figs. 5g and 5h), as the peduncle is very long, almost four times as long as deep and about as long 

 as the first joint of the endopod; second joint of the endopod slightly longer than the first joint; 

 exopod from slightly less to slightly more than half as long as first joint of the endopod. 



Length of a female with marsupium 3.3 mm . 



Remarks. This fine species is easily distinguished from all other forms of the genus known 

 to me by the very long peduncles of the uropods. 



Occurrence. This species has been taken by the "Ingolf" at two stations. 



Davis Strait: St25: Lat 63 30' N., Long. 54 25' W., 582 fm., temp. 3.3; n spec. 

 St 24: Lat, 63 06' N., Long. 56 oo' W., 1199 fm., temp. 2.4; 6 spec. 



The marsupium of one of the females from Stat. 25 contains two ovisacs of an unknown species 

 of the family Choniostomatidse. It is, I believe, the first time that the existence of a species of this 

 family of parasitic Copepods has been observed in any form of the order Tanaidacea. 



48. Leptognathia alba n. sp. 

 (PI. VII, figs. 6 a 6e.) 



Specimen without marsupium. The single specimen is either a female without mar- 

 supium or, judging from the thick antennulse, more probably a male so far from maturity, that the 

 fourth antennular joint has not been divided into two joints. The body is conspicuously more robust 

 than in the preceding forms. 



Antennulse (fig. 6 a) slightly more than two-thirds as long as the carapace, very robust. First 

 joint slightly longer than the three other joints combined, not fully two and a half times as long as 

 deep and tapering feebly; second joint thick, as long as the depth of the first and somewhat produced 

 above; upper margin of third joint only about one-third as long as that of the second; fourth joint 

 somewhat shorter than the second. Antenna? with fifth joint scarcely half as long again as the 

 fourth, which is as long as the sixth. 



Chelipeds (fig. 6b) moderately robust. Carpus somewhat more than twice as long as deep, 

 with the proximal half of the upper margin somewhat concave; the distal half is feebly expanded 

 downwards. Chela somewhat shorter than the carpus, somewhat more than twice as long as broad, 

 oblong-triangular in aspect, without serrration; the anterior distal corner of the hand not rounded; 

 the movable finger somewhat broad and somewhat shorter than the anterior margin of the hand. 



Thoracic legs somewhat slender. Second and third pairs subequal (fig. 6c); posterior spine on 



