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



The remaining thoracic apioendagcs, on the coiitraiy, are abundantly furnisliecl with 

 long, unbranched hairs, and short, stout, serrated, and smooth spines ; the latter are 

 ■ especially developed at the distal extremity of each joint just before its articulation with 

 the succeeding joint. 



The proximal joint of the limb is the stoutest, and except in the two penultimate 

 limbs, the lono'est, its margin is clothed with fine delicate unliranched hairs ; the 

 second joint is shorter, and the third shorter still ; the fourth and fifth joints in the 

 posterior limbs are considerably elongated ; the distal extremity of the terminal joint is 

 separated off by a suture, and ends in a sharp spine. 



The abdominal appendages present no peculiarities except the terminal uropoda, which 

 have been well described and figured by Studer; ^ the endopodite becomes fused with the 

 protopodite, and is extraordinarily elongated ; the short exopodite is spine-like, and can 

 l)e fixed at right angles to the rest of the appendage, forming in this way a defensive 

 apparatus, which, as Studer suggests, no doubt secures to the animal a greater freedom 

 from the attacks of l)irds and other enemies. For figures and fuller description of 

 this structure the above-mentioned Memoir by Studer should be consulted. The 

 structure of the uropoda in this species recalls that characteristic of the family 

 Sphseromidje. 



Two specimens of Serolis latifrons dredged off Possession Island in 210 fathoms 

 present some variations from all the other specimens ; they are both females, with fully 

 developed brood lamelte, and are approximately of the same size, measuring 28 mm. in 

 length by 23 mm. in breadth ; the proportions therefore of these specimens are nearly the 

 same as in the males of the typical Kerguelen form ; the sterna of the abdominal segments, 

 however, are quite like those in the females. In one specimen the posterior two pairs of 

 brood lamellse of the left side overlap those of the right, the two anterior pairs are normal. 

 This variety is quite different in colour, being of a uniform yellowish brown, with a few 

 scattered black spots, especially upon the caudal shield. The shape of the caudal shield 

 is different from that in the Kerguelen specimens ; it is considerably narrower, and the 

 lateral margins are almost straight, with only a very slight outward bulging ; the posterior 

 epimera of the body come therefore to project considerably beyond the margin of the 

 caudal shield, which is almost completely triangular in shape. 



One of the specimens is figured on PL II. fig. 1, and may be compared with the 

 figures of Studer and Miers of the normal variety. 



Station 148, January 3, 1874; lat. 46° 47' S., long. 51° 37' E. ; 210 fathoms; 

 bottom, hard ground, gravel, shells. 



Kerguelen Island, January 13, 1874; Cascade Bay, 5-40 f.ithoms. January 17, 

 1874; Royal Sound, 25 fathoms. 



1 Archivf. NaturgescL, 187U. 



