ISOPODS OF NORTH AMERICA. 51 



"The fossorial limbs, which form the second pair, are much longer 

 and stouter than the succeeding abdominal limbs. The first joint is 

 long and curved, the second is very minute, the third and fourth are 

 subequal and rather less than one-half of the length of the basal joint; 

 the first two joints have no spines, the third has a single strong spine 

 on the inner margin just before it articulates with the succeeding joint, 

 and a tuft of hairs on the corresponding opposite side; the fourth 

 joint has two strong spines on the inner and a single spine on the outer 

 side, besides hairs and more slender spines; the fifth is shorter than 

 either of the preceding, its inner margin is fringed with five stout 

 spines, increasing in length toward the extremity of the joint, and two 

 strong spines besides more slender ones on the outer side; the terminal 

 joint of the limb is elongated and claw-like, toothed along the inner 

 margin. These appendages like the preceding have no exopodite, and 

 they do not differ in the two sexes to any appreciable extent. 



"The succeeding thoracic appendages are similar to each other and 

 very much more slender than the preceding limbs; the proportionate 

 length of the joints is, however, the same, the second being, as in the 

 fossorial limbs, extremely minute. The spines with which the ter- 

 minal joints of these limbs are ornamented are also more slender than 

 those of the second pair of thoracic appendages. 



"The abdominal appendages, with the exception of the uropoda, 

 are similar to each other: all the five pairs consist of an elongated 

 basal joint and of two subequal, rather shorter setose rami; the exopo- 

 dite is divided by a suture into two joints. 



"The uropoda are short and biramose, with an elongated basal joint 

 and two rami, the outer is the shorter. 



"Station 23, off Sombrero Island, March 15, 1873; latitude, 18 24' 

 north, longitude, 63 28' west; depth, 450 fathoms; Pteropod ooze."- 

 BEDDARD. 



11. Genus SPHYRAPUS Norman and Stebbing.^ 



First two segments of thorax fused with the head to form a cara- 

 pace. Eyes absent. Second pair of antennae without scale. Exopods 

 present on first two pairs of legs. Gnathopods in male with carpus 

 and merus much more elongated than in female. Second pair of legs 

 in male of extraordinary length. Pleopoda well developed, with both 

 branches bi-articulate. Flagellum of first antenna in male with dense 

 bunches of sensory hairs. 



Challenger Report, XVII, 1886, pp. 112-113. 



ft See Sars' Crustacea of Norway, II, 1899, pp. 8-9, and Norman and Stebbing, 

 Trans. Zool. Soc. London, XII, 1886, p. 97, for characters of genus. Sars says that 

 only the first thoracic segment is fused with the head. 



