Zoological Society. 69 



in its dissimilar molars, the types of two genera : the molars of its 

 upper jaw represent those of both jaws of Ctenomys ; those of its 

 lower jaw correspond with the molars of both jaws of Poephagomys. 

 The characters distinguishing the new species of Ctenomys are 

 chiefly those of colour. The Cten. Brasiliensis is described by M. de 

 Blainville as being shining rufous above, and reddish white below. 

 The new species may be characterized as the Ctenomys Magellanicus. 

 Captain King states that this " little animal is very timid ; feeds 

 upon grass ; and is eaten by the Patagonian Indians. It inhabits 

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

 holes, it would appear to be very abundant." 



A second animal exhibited appears, like the preceding, to represent 

 in the more southern latitudes of South America a genus whose type 

 was originally observed in Brasil. Mr. Bennett regarded it as a 

 second species of Kerodon, F. Cuv., chiefly distinguishable from the 

 one discovered by Prince Maximilian of Wied by its more uniform 

 colour. Excepting a slight dash of white behind the ear, and a 

 longer line of the same colour marking the edge of each branch of 

 the lower jaw, the animal is entirely grey ; the upper surface being 

 distinguished from the under by a greater depth of tint, and by the in- 

 termixture of a free grizzling of yellow and black. The crowns of 

 the molar teeth, as in the typical species, consist of bone surrounded 

 by two triangles of enamel, the bases of which are connected together 

 by a short line of enamel passing from the one to the other : all the 

 lines being slender and sharply defined. 



For this species Mr. Bennett proposed the name of Kerodon 

 Kingii. 



The third animal exhibited was remarked on as constituting a new 

 species of Cavy, distinct from all those that were previously known, 

 including the two which have recently been described by M. Brandt 

 in the ' Nouveaux Memoires de I'Academie Imperiale de St. Peters- 

 bourg.' Mr. Bennett characterized it as the Cavia Cutleri, King 

 MSS. 



The general form of the animal is probably similar to that of the 

 restless Cavy, Cavia Cobaya, Gmel., popularly known as the Guinea- 

 pig. It is covered universally by long, smooth, glossy, black liairs, 

 which are slightly tinged with brown. Its ears are rather large, 

 broadly expanded, and hairy ; and between them the hairs are longer 

 than those on the adjoining parts, occasioning a slight appearance of 

 a crest. On the middle of each cheek the hairs radiate as from a 

 centre, almost in a similar manner to that in which they spread from 

 around the crown of the bonneted Monkeys, and the skin is conse- 

 quently left in the middle point almost bare. The dentition is alto- 

 gether that of the restless Cavy, and the incisors, as in it, are white. 

 The skull is rather more expanded laterally, which gives to it an 

 appearance of comparative flatness. 



" This animal was known, on the survey, by tlie name of the Pe- 

 ruvian Cavy. The specimen in the Society's collection was presented 

 to one of the officers of the Beagle by an American sailing-master, 



