100 *S'. /. Smith — Crustaceans of the Atlantic Coast. 



individual, are proportionally shorter than in that species, and con- 

 sequently the entire endopod is correspondingly shorter, being only 

 very slightly longer than the carapax. The articulation between the 

 two divisions of the carpus is imperfect, very indistinct, and in some 

 specimens is made out only with the greatest difficulty, even when 

 the appendages in question have been specially mounted for the pur- 

 pose ; in P. roseuni, however, this articulation is perfectly distinct as 

 it is in the five pairs of pereopods in both species. 



The five pairs of pereopods have precisely the same form and struc- 

 ture as in P. roseum, and, as in that species, increase successively in 

 length posteriorly, but differ in the lengths of the three longest seg- 

 ments in the same way as the second gnathopods. In P. truncatum 

 the length of the pereopods varies considerably in diiferent speci- 

 mens of the same sex and age, and even on the dififerent sides of the 

 same specimen, but the first pereopods are about a third as long as 

 the entire body of the animal and the posteiior pair are fully one- 

 half as long, or about as long as the second pair in P. roseum. 



The proportions of the segments of the abdomen are almost exactly 

 as in P. roseurii : the five anterior segments are sub-equal in length, 

 though increasing very slightly posteriorly, and the fifth is about as 

 broad as long and the first about a third broader than long ; the sixth 

 segment is about once and a half as long as the fifth and about two- 

 fifths as long as broad. The telson (figures 3 h and 4) is considera- 

 bly shorter than the sixth segment, and, at base, about three-fourths 

 as broad as long, sub-triangular, and truncated at the tip, which is 

 about a third as bi'oad as the base; the lateral margins are armed 

 for a little more than the distal half of the length, with about seven 

 small spines which are rather more crowded proximally ; the tip is 

 truncated and armed with two pairs of strong spines several times as 

 long as those upon the lateral margins, and a median pair of slender 

 plumose setae, which are slightly longer in the male than in the 

 female. In P. rosemn the telson is as long as the sixth segment of 

 the abodmen, the tip is rounded, and the lateral and terminal spines 

 form a single series. The lamellae of the uropods are somewhat 

 shorter and broader in proportion to the length, but absolutely of 

 about the same breadth as in P. roseum. 



Gulf of St. Lawrence!, ISl'i (J. F. Whiteaves) : oflT the Bay of 

 Chaleurs, 50 and 70 fathoms, August 4,— between twenty and thirty 

 specimens; and also between Bradelle Bank and Miseou Island, 45 

 fathoms, mud and stones, August 7, — one male. 



