AMPHIPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 475 
modified his original description in one or two points in which he found that the 
additional specimens showed some slight variation from those at first described. In 
1903 he also had identified as O. abyssorwm specimens obtained from the Atlantic 
by the Oceana. 
The Scotia collections contain an enormous number of specimens from the various 
localities given above, and a comparison of these with co-types of WALKER’S species showed 
that they were the same as the forms described by him under the name O. rossw. A 
comparison of the different specimens from the South Orkneys and other Scotza localities 
with co-types of WaLKER’s species supplied by the British Museum, and with specimens 
collected by the Nimrod Expedition, showed that the species varied greatly not only 
in size but also in several points which had been relied upon by previous authors for 
the description of different species—for example, in the second gnathopod, some of the 
specimens having the palm strictly transverse, while in others it was slightly produced 
so as to give the gnathopod almost a chelate character; in the postero-lateral angle to 
the third pleon, which in some is quadrate and in others more or less broadly rounded ; 
and in the proportions of the two branches of the third uropods. There are, of course, 
also differences between the sexes, the males having the lower antenna considerably 
longer than the females, and having the branches of the third uropod supplied with more 
numerous long plumose sete, though some similar setee are present in the female. An 
examination of young forms appears to show that these setze are only developed to the 
full extent in older specimens, there being fewer in younger forms. 
I was able also to compare these specimens with a specimen of O. proxima 
Chevreux from Port Charcot, kindly sent to me by Monsieur CHEvREuX, and I have 
come to the conclusion that this species is the same as O. rossiz, the differences which 
M. Cuevrevx points out being accounted for by the variations mentioned above. In 
the character of the eyes and in other points it is quite the same as a specimen of 
O. rossv of moderate size; on the other hand, as M. CHEvREUX points out, it is con- 
siderably larger than the forms from the North Atlantic on which he originally 
described the species O. proxima. From the Vienna Museum I obtained specimens of 
Anonyzx chilensis Heller, taken by the Novara at Chili. This proved to be about half the 
size of O. proxvma ; it differs a little in the shape of the eye and in the somewhat smaller 
size of the rounded prominence on the first segment of the urus, but in all other points 
I can find nothing to distinguish it from O. rossii Walker. In Anonyx chilensis the 
eye is almost oval, widening slightly below, and it is colourless in the spirit specimens 
and probably was red in the living animal, as described by Sars in O. obtusa. In large 
specimens of O. rossi from Antarctic regions, the eye usually differs somewhat in shape, 
being much narrower above and wider below, and in most of them it is dark in colour 
in spirit specimens, though in many, and especially in forms preserved originally in 
formalin, there is still a reddish tinge to be seen. Moreover, even in the Antarctic 
specimens there is some variation in the size, shape, and colour of the eyes, and conse- 
quently I do not think this slight difference sufficient to distinguish Anonyx chalensis 
