36 PATAGONIAN EXPEDITIONS : ZOOLOGY. 



The original basis of Cteiiomys mageUanicus was a single specimen col- 

 lected by Captain King at Cape (or Port) Gregory, on the northern side 

 of the Strait of Magellan, and hence on the mainland of Patagonia. This 

 specimen was considered by King to be "rather a young one," "from 

 the size of the jaw, as compared with the abundant remains of this little 

 animal which are scattered over the surface of the ground" (Trans. Zool. 

 Soc. Lond., II, i84'i, p. 85) ; and the skull, as figured by Bennett and 

 Waterhouse, seems to bear out this conclusion, all of the sutures being 

 shown to be ver^' distinct, as in a young animal. 



As late as 1848, Waterhouse stated (Mamm., II, p. 283) that, so far as 

 he knew, but one specimen of this species of Ctenomys had been brought 

 to Europe ; and to this day little has been added to our knowledge of its 

 range or habits beyond the three or four lines respecting the latter con- 

 tributed by Captain King, namely : "The little animal is very timid; feeds 

 upon grass, and is eaten by the Patagonian Indians. It dwells in holes, 

 which it burrows, in the ground : and, from the number of holes, it would 

 appear to be very abundant. It inhabits the east entrance of the Strait 

 of Magelhaens at Cape Gregory and the vicinity." 



In comparing this species with the other species of the genus then 

 known, Waterhouse assumed that its small size was not due to immaturity, 

 "all the teeth being fully developed." As shown, however, by the large 

 series of an allied species in the present collection, the skull more than 

 doubles in size (in bulk, not in linear dimensions) after "the teeth are fully 

 developed" ; and furthermore, that his specimen was really quite young, 

 and probably also a female, as indicated by the straightness of the zygo- 

 matic arches. 



In this connection, as bearing upon the comment on Ctenomys neglectus 

 which here follows, it is worth while to note the unlikeness of Bennett's 

 and Waterhouse's figures of the same skull, especially in respect to the 

 position and direction of the fronto-parietal sutures, which are correctly 

 drawn in Bennett's figure, and very erroneously represented in that pub- 

 lished by Waterhouse. 



In 1900 Dr. Nehring published (/. c.) as new a Ctenomys neglectus based 

 on a Patagonian weathered skull, of which he gives a figure. He com- 

 pares this skull with Bennett's figure of the skull of C magellaniais, and 

 is able to distinguish numerous differences between them, which appear 

 to him weighty enough to warrant his treating this skull as the basis of a 



