404 REPORT OF COMMISSIONER OF FISH AND FISHERIKS. 



tween them urc two less evident tubercles on the front margin of the 

 segment; the dorsal surface tapers behind, and is bounded laterally 

 by carinas; below, the segment is Avedge-shaped, but not carinated; 

 behind, it is separated from tlie third segment by a constriction not 

 quite as pronounced as that in front. The third segment presents two 

 rather more evident median tubercles in front on the dorsal siu-face, 

 which is defined laterally by carinae, fading away at about the middle 

 of the segment ; below, it is wedge-shaped and carinate in the males, 

 but membranous along the median line in the females, as are the 

 remaining segments more widely in that sex. In the males they are 

 hard and chitinous throughout, rounded and scarcely wedge-shai^ed. 

 The fourth segment is slightly longer than any of the others, and bears, 

 near the anterior end of its dorsal surface, an oval depression with slight 

 elongated elevations at each side. A similar structure occm^s on the 

 fifth and sixth segments, which are of decreasing length. The seventh 

 is much the shortest thoracic segment, not being longer on the median 

 line than the head ; it is somewhat produced laterally. 



The first pair of legs (pi. XI, fig. 70 e) are not as stout as in Atithura 

 2)olita, and are more flexible ; the carpus is the shortest segment, and 

 is triangular, broader than long; the preceding segment, or merus, 

 shows but little in an external view, but is more evident in an inner 

 view, as shown in the figure, and is much broader than long; the pro- 

 podus is nuich swollen proximally on its anterior or upper side; im- 

 mediately in front of the end of the carpus it bears a stout tooth ; the 

 dactylus is strong, and tipped with a curved claw. In the second and 

 third pairs of legs the carpus is triangular, but in the posterior pairs 

 it is more elongated so as to distinctly separate the merus from the 

 i>ropodus. 



The pleon is short, the telson triangular, acute at the apex. Uropods 

 with the basal segment strongly- carinate externally, terminal plate 

 acutely triangular, proximal superior plate oval, curved and attached 

 by its side, nearlj^ meeting its fellow of the opposite side above. First 

 pair of pleopods (pi. XI, fig. 70/) with the external ramus semi-oval; 

 internal ramus less firm in texture, ligulate, ciliated distally. Second 

 pair of i3leopods in the males (pi. XI, fig. 70^) furnished with a slender 

 stylet articulated at about the middle of the inner, posterior, lamella, 

 (ind extending beyond its end. Both the lamellae are crossed by a trans- 

 rerse suture just beyond their middle, at the point where the stylet is 

 jittached to the inner one. 



Length 28"^™ ; breadth 2.2'"'" ; females about one-third smaller. The 

 (olor is usually light yellowish brown, or sometimes somewhat darker. 

 Kit not as pronounced as in the other members of the family, and nearly 

 the same throughout. 



From P. norvegica G. O. Sars* our species is distinguished by the eyes, 

 which, though inconspicuous, are present. It lacks the tubercle de- 



* Chr. Vid. Selsk. Forli., 1872, p. 88, 1873. 



