MTJE1D2E. 229 



three molars is 0,0068, the dimensions of Schlosser's spe- 

 cimens ranging from 0,0067 to 0,0073. Purchased, 1884. 



Cricetodon gergovianus (P. Gervais 1 ). 

 Syn. Mus gergovianus^ P. Gervais 2 . 

 Hob. France. 



27756. The greater portion of the left ramus of the mandible ; from 

 the Lower Miocene of Cournon (Puy-de-D6me), France. 

 The length of the space occupied by the three molars is 

 0,0058, the length in the type form being 0,006 according 

 to Schlosser. It is almost impossible to distinguish the 

 present specimen from the mandible of the Upper-Miocene 

 C. medius (No. 33269) ; and it appears quite probable that 

 the two may be specifically the same. 



Croizet Collection. Purchased, 1848. 



Cricetodon sansaniensis, Lartet 3 . 

 This species is rather larger than the Hamster. 

 Hob. Europe. 



33268. A molar tooth ; from the Middle Miocene of Sansan (Gers), 

 France. Presented by M. Ed. Lartet. 



48190. Three fragments of the mandible ; from the Middle Miocene 

 of Steinheim, Bavaria. The length of the space occupied 

 by the three molars is 0,0084. Purchased, 1877. 



Genus HESPEROMYS, Waterhouse 4 . 



Molars narrow, with tubercles arranged in pairs, which soon wear 

 away, leaving the crown flat with indenting folds. Cranium with 

 or without marked supraorbital ridges. 



Hesperomys, sp. 1. 

 Hob. S. America. 



17616. Anterior portion of the cranium of a comparatively large 

 species, wanting the incisors, but showing the cheek- 

 teeth ; from a cavern near Lette-Lagoas, Brazil. This 

 specimen is allied to the existing H. angouya, Desm., but 

 is distinct. Claussen Collection. Purchased, 1845. 



1 Zool. et Pal. Fransaises, 1st ed. vol. ii. explan. pi. xlviii. (1848-52), Mus. 



2 Loc. cit. 



3 Notice sur la Colline de Sansan, p. 20 (1851). 



4 Zoology of the Voyage of the ' Beagle,' vol. i. p. 75 (1839). 



