114 THE VOYAGE OF H.M.S. CHALLENGER. 



side just before its articulation with the next joint, which is extremely minute 

 and might easily be overlooked ; it is wedged in between the second and third joints, 

 and is only apparent on the inner side of the limb. The fourth joint is longer 

 and stouter and has a number of hairs along the inner margin. The two 

 " fingers " cross at their extremity ; they are serrate along the margins which come 

 in contact. 



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 towards 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 terminal joints of these limbs are ornamented are also more slender 

 than those of the second parr of thoracic appendages. 



The abdominal appendages, with the exception of the uropoda, are simUar to each 

 other ; all the five pairs consist of an elongated basal joint and of two subequal, rather 

 shorter setose rami ; the exopodite 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 ; lat. 18° 24' N., long. 63° 28' W.; 

 depth, 450 fathoms ; Pteropod ooze. 



Leiopus, F. E. Beddard. 



Leiopus, F. E. Beddard, Proc. Zool. Soc. Lond., 1886, pt. i. p. 11G. 



Body depressed and extremely narrow and elongated, wider anteriorly than 

 posteriorly. Head prolonged in front into a loug pointed rostrum ; ocular lobes long, 

 triangular, pointed, eyes absent. First free segment of thorax with epimera pro- 

 longed anteriorly into a spine, remaining segments with small epimera, which in the last 



