AMPHIPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 189 



Genus WALDECKIA Chevreux, 1906 

 ( = CHARCOTIA Chevreux, 1905, name preoccupied). 



Waldeckia zschauii (Pfeffer). 



Anonyx zse/Mn Pfeffer, 1888, p. 87, fig. 1. 

 Orchomenopsis zschauii Stebbing, 1906, p. 85 (part). 

 Charcotia obesa Chevreux, 1905, p. 163, fig. 3. 

 Waldeckia obesa Chevreux, 1906i3, p. 15, figs. 8-10. 

 Walker, 1907, p. 10, pi. ii. fig. 4. 



Station 411, Coats Land, lat. 74 1' S., long. 22 W.; 161 fathoms. 12th 

 March 1904. Many specimens, the largest 16 mm. long. 



Although I have been unable to examine specimens of Anonyx zschauii Pfeffer, 

 as those described by him did not belong to the official collection of the German Expedi- 

 tion of 1882-83, and consequently were not deposited in the Hamburg Museum, I feel 

 confident that my specimens must be referred to his species. His description of the 

 great obesity of the body, and particularly of the dorsal process on the first segment of 

 the urus, which is so distinct from that of other species with which it might otherwise 

 be confused, leaves no doubt upon the subject. In this species, in place of the more or 

 less rounded prominence on the first segment of the urus, the process rises abruptly 

 behind the usual depression into a sharp tooth, from which it slopes downwards towards 

 the next segment ; this is shown clearly also in PFEFFER'S figure, although the figure is 

 rather small. Mr STEBBING in 1906 referred his species Orchomene cavimanus to 

 PFEFFER'S species, but an examination of the mounted slides of the Challenger collection 

 in the British Museum shows that the first gnathopod of 0. cavimanus has the propod 

 broad and not narrowing distally as in W. zschauii, and, judging from the description, 

 the process on the urus does not appear the same as in that species, and it appears to me 

 that O. cavimanus Stebbing is more properly referred to the widespread and variable 

 species 0. chilensis (Heller) ; see p. 474, where the question is further discussed. 



I did not at first compare my specimens with the descriptions of Waldeckia obesa 

 Chevreux, but the shape of the basal joint of the third perseopod in one of the slides 

 I had mounted proved to be so similar to the figures given by both CHEVKEUX and WALKER 

 that a full comparison was made, with the result that my specimens proved to be 

 identical with that species also. The figures given by CHEVREUX and WALKER show the 

 great obesity of the body and the great prolongation backwards of the fourth side plates 

 better than PFEFFER'S ; but, on the other hand, they hardly show so well the character of 

 the process on the urus, though from their descriptions it seems evident that they were 

 dealing with the same structure. 



I have compared the Scotia specimens with those collected by the Discovery and 

 referred to this species by Mr WALKER, and find no essential difference ; in the Discovery 

 specimens the third segment of the pleon is slightly more compressed and elevated into 

 a blunt dorsal tooth, while the tooth on the first segment of the urus is a little shorter 

 than in the Scotia specimens. 



. (ROY. soc. EDIN. TRANS., VOL. XLVIII., 471.) 



