100 
S. L 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. roseum , 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. truncation 
the length of the pereopods varies considerably in different speci- 
mens of the same sex and age, and even on the different sides of the 
same specimen, but the first pereopods are about a third as long as 
the entire body of the animal and the posterior 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. roseum : 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 broad 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. roseum 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!, 1873 (J. F. Whiteaves) : off the Bay of 
Chaleurs, 50 and 70 fathoms, August 4, — between twenty and thirty 
specimens; and also between Bradelle Bank and Miscou Island, 45 
fathoms, mud and stones, August 7, — one male. 
