AMPHIPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 215 



terminal setse or notcli. In one specimen I find one half with a notch and the other 

 without (Plate 1. fig. 18) ; in others it closely resembles the figure given by Chevkeux. 

 The species is found in all sub-Antarctic seas. 



Atyloides serraticauda Stebbing, 



Atyloides serraticauda Stebbing, 18S8, p. 920, pi. Ixxviii., and 1906, p. 36. 

 „ „ Walker, 1907, p. 33. 



,, ,, Chevreux, 1906b, p. 87. 



Chilton, 1909a, p. 627. 

 (?) Schraderia gracilis Pfeffer, 1888, p. 141, pi. ii. fig. 5 (no description, only one figure). 



South Orkneys, Scotia Bay, Station 325 ; shore pools. 2nd February 1904. A 

 few specimens, the largest 12 mm. long. 



In fully grown specimens this .species may be recognised by the long antennae, 

 gnathopoda, and perseopoda, and particularly by the serrations on the side plates and on 

 the hinder margin of the third pleon segment. These serrations may, however, be 

 almost completely absent in smaller specimens, and the species is by no means so easy 

 to recognise, and the identification then depends mainly on the telson. 



Schraderia gracilis was named in 1888 by Pfeffek, but not described, only a 

 general figure of the whole animal being given. This figure without drawings of the 

 separate appendages is quite insufficient for identification in this group, which contains 

 so many species very nearly alike in general appearance ; and as it is not now possible 

 to ascertain from which individual specimen the drawing was made, Pfeffer's species 

 must remain doubtful. There are several specimens in the collection of the Hamburg 

 Museum labelled "Schraderia gracilis," and these prove to belong to the species now 

 under consideration, Atyloides serraticauda Stebbing. 



The species is widely distributed in Antarctic and sub- Antarctic seas. 



Atyloides calceolata, sp. nov. (Plate II. figs. 21-23.) 



South Orkneys, Scotia Bay, Station 325 ; 10 fathoms. A few specimens, 

 mostly imperfect, about 5 mm. long. 



Specific Description. — Similar to Atyloides serraticauda in general shape of body, 

 in the serrations on the anterior side plates, the posterior margins of the basal joints of 

 the perseopoda, the posterior margin of the third segment of the pleon, and in the telson ; 

 diflfering mainly in the antennae. The first antenna (fig. 21) with the first joint longer 

 and considerably stouter than the second, its lower margin bearing distally an acute 

 spine with another shorter spine placed laterally, a few long setae near the end joint ; 

 second joint bearing on its under surface two well-marked calceoli of characteristic shape, 

 one on a little prominence at a short distance from the proximal end and the other near 

 the distal end, some fine setae at the end of the joint ; third joint short; the whole 

 antenna about as long as the body. 



Second antenna (fig. 21) with the gland cone very acute ; the third joint short, pro- 



(roy. soc. edin. trans., vol. xlviii., 497.) 



