ISOPODS OF NORTH AMERICA. 443 



'' First thoracic legs very different in adult specimens of the two 

 sexes, but in immature males nearly as in adult females. In the male 

 they are rather long, robust; third joint is distally much expanded 

 above and produced into a triangular process directed upward; fourth 

 joint expands above gradually from the base, forming a broad but 

 rather low process, a portion of the inner surface of which is furnished 

 with numerous exceedingly long hairs. Fifth joint has the upper 

 margin very short, without any process, but it expands below, its 

 lower margin is several times longer than the upper, and besides it is 

 produced into a very long oblong-triangular process, the inner side 

 and both margins of which are closely set with longer very long hairs; 

 the upper margin of the process is straight nearly to the insertion of 

 the hand, and the distance from this insertion to the end of the proc- 

 ess is longer than the distance from the insertion to the base of the 

 joint. The hand is very large, a little broader near the end than at 

 the base, two and a half times longer than deep; upper margin strongly 

 convex, lower margin rather concave from the base to the distal proc- 

 ess, which occupies the major portion of the short palmar edge; this 

 process is low, broad, its margin more or less convex and divided into 

 three or four teeth; the lower major portion of the inner surface of 

 the hand is closely set with very long hairs. Seventh joint very long, 

 much curved, especially at some distance from the base, claw-shaped, 

 with fine, simple hairs spread along both margins and on the inner 

 side, but without spines; the claw itself is very short. In the female 

 the legs are much shorter than in the male, robust; process on third 

 joint proportionately a little longer and broader, that on fourth joint 

 a little longer than in the male; fifth joint much smaller than in the 

 male, its lower process small. Hand much smaller than in the male, 

 subtriangular, a little more than half as long again as deep; upper 

 margin very convex, two and a half times longer than the lower, which 

 is straight, with many long hairs; distal end somewhat longer than 

 the lower margin; palmar edge feebly convex, with an angular notch 

 at the lower end, so that the usual spine, which is strong and moder- 

 atel} 7 long, is situated a little behind the edge; the edge from the 

 'claw 'to the notch is occupied by five or six saw-teeth gradually 

 increasing in size downward, and besides adorned with some stiff setae 

 pectinate along their upper margin; finally, the angle between lower 

 margin and palmar edge measures about 110. Seventh joint with 

 the claw regularly claw-shaped, when extended reaching slightly 

 beyond the notch mentioned; the major portion of the lower margin 

 of the joint is adorned with rather slender spines, serrate along the 

 lower margin, and some fine hairs. 



"Abdominal shield slightly broader than long; lateral margin 

 unarmed, only with the usual tooth and notch at the end; posterior 

 margin, reckoned from the notch, is strongly and rather evenly 

 curved. 



