168 UNGULATA. 



Nesodon ovmus, Owen 1 . 



This is the smallest species of the genus. 

 Hab. S. America. 



35683. The cranium, imperfect posteriorly ; from the Tertiary of 

 (Fig.) the south-east of Patagonia. This and the next speci- 

 men are the types of the species, and are described and 

 figured by Owen in the Phil. Trans, for 1853, p. 291, 

 pis. xv., xvi. 



Presented by Admiral Sir B. J. Sulivan, K.C.B., 1853. 



35684. The right ramus of the mandible, associated with the pre- 

 (Fig.) ceding. Described and figured by Owen, op>. cit. 



Presented by Admiral Sir B. J. Sulivan, K.C.B., 1853. 



Genus TOXODON, Owen 2 . 



Dentition : — I. g, C. -, Pm. g, M. -^ All the teeth grow from per- 

 sistent pulps ; the lower canines are minute, the incisors large, and 

 the crowns of the latter and of the cheek-teeth strongly curved. The 

 structure of the cheek-teeth is a simplification of the plan obtaining 

 in Nesodon. The characters of the base and hinder part of the 

 cranium agree very closely with those of the Suidce. Five species 

 are recognized by H. Gervais and Ameghino 3 . 



Toxodon platensis, Owen 4 . 



Syn. Toxodon angustidens, Owen °. 



This is the type species, and is nearly equal in size to Hippopo- 

 tamus amphibius. 



Hab. South America. 



49197. The cranium, wanting many of the teeth ; from the Pleis- 

 tocene of Buenos Ayres. Purchased, 1878. 



19948. The anterior extremity of the cranium, wanting all the teeth 



except the outer left incisor ; from the Pleistocene of 

 Buenos Ayres. Purchased, 1846. 



19949. The mandible, wanting many of the cheek-teeth ; from the 



Pleistocene of Buenos Ayres. Purchased, 1846. 



1 Phil, Trans, vol. cxliii. p. 291 (1853). 



2 Zool. of Voyage of H.M.S. 'Beagle/ pt. 1, p. 16 (1840). 



3 Les Mammiferes Fossiles de l'Arnerique Meridionale, pp. 81-85 (1880). 



4 Loc. cit. 



5 Bep, Brit. Assoc, for 1846, p. 65 (1847). 



