AMPHIPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 217 



A special variety of the species was obtained as follows : 



South Africa, entrance to Saldanha Bay ; 25 fathoms. 21st March 1904. 



This species is one that is very widely distributed in sub- Antarctic seas, and is usually 

 found in shore pools or in shallow waters around the coast. It has been pointed out by 

 several authors that specimens of it vary considerably ; probably when the different 

 forms are carefully compared it may be possible to distinguish several local varieties, 

 but I think, in the present state of our knowledge, that Mr STEBBING is right in uniting 

 the various forms under this one name. 



Through the kindness of the authorities of the Hamburg Museum I have been able 

 to examine the type and other specimens of Stebbingia gregaria Pfeffer, and I find 

 that they undoubtedly belong to this species. Several of them are of comparatively 

 large size, but they show no distinction of importance from the ordinary form, and the 

 small accessory flagellum of the upper antenna is present. Various authors have 

 described this accessory flagellum as being absent in the specimens examined by them, 

 and, though I have usually been able to find it, there are a few specimens that I have 

 seen in which I have been unable to do so, although in all other points they seem to 

 belong to the species ; and there seems little doubt, as pointed out by WALKER and 

 others, that in this as in some other species the small accessory flagellum may some- 

 times be actually absent ; probably this is more commonly the case in older forms. 



Of the local varieties I can at present indicate two : 



(1) The form described under the name Atylus megalophthalmus Haswell. In this 

 form the head has a rostrum nearly half as long as the first joint of the upper antenna ; 

 the accessory flagellum, though apparently present, is small, short, and fused to the third 

 joint of the peduncle ; and the telson has the posterior portion of each lobe somewhat 

 rounded arid without setae. 



(2) The forms mentioned above from South Africa, Saldanha Bay. In general 

 appearance, and in the antennae and gnathopods, etc., these agree closely with forms from 

 other localities, but they differ somewhat markedly in the telson, the posterior portion 

 of each lobe of which is cut into three or four acute teeth and is without setae. In 

 some forms from other localities there may be two such teeth, but, so far as I know, not 

 more, and the telson usually bears two or more long setae on each lobe. The telson in 

 the Saldanha Bay variety closely resembles that described by CHEVREUX for Atyloides 

 longicornis from Port Charcot, etc., a species which appears to me to be little more than 

 a variety of Paramcera austrina in which the accessory flagellum is absent and the 

 gnathopods are rather small. 



Even in the more typical forms there seems to be considerable variation in the size 

 and shape of the gnathopods. In some the propod is oblong, with the palm almost 

 transverse, as shown by Mr STEBBING in his drawings of Atyloides australls Miers ; in 

 others the propod is more oval, with the palm somewhat oblique ; the length of the 

 carpus is also subject to variation, and the setse seem to be more abundant on the 

 antennae and gnathopods in some specimens than in others. 



(ROY. soc. EDIN. TRANS., VOL. XLVIII., 499.) 



