249 RODENTIA, 
Miocene of Sauvetat. The teeth of these specimens agree 
precisely with those figured by Gervais (op. cit. figs. 18, 
18a), and are provisionally referred to Protechinomys 
breviceps. 
Bravard and Croizet Collections. Purchased, 1848-52. 
27689. The palate, showing the cheek-dentition of both sides; from 
the Lower Miocene of St. Yvoine (Puy-de-Dome). 
Croizet Collection. Purchased, 1848. 
27757. The right upper cheek-dentition ; from the Lower Miocene 
of Perrier (Puy-de-Dome). 
Croizet Collection. Purchased, 1848. 
Genus ARCH ZZOMYS, Laizer and Parieu’. 
Cheek-teeth rootless; the enamel-folds continuing across the 
crown and dividing it into lamine; the lamine are subequal in 
the lower teeth, but in the upper the first lamina is the largest. 
The genus is connected by the last with Theridomys, aoe leads on 
to the Chinchillide. 
Archzomys laurillardi, P. Gervais’ (ex Bray.). 
This is the largest species; there are four lamine of dentine on 
the worn crowns of the upper molars. 
Hab. France. 
25099. Fragment of the cranium, showing the cheek-dentition of 
the left side; from the Lower Miocene of Cournon (Puy- 
de-Dome), France. This specimen agrees with the type 
cranium figured by P. Gervais in the Zool. et Pal. Fran- 
caises, 2nd ed. pl. xlvii. figs. 15, 15a, with the exception 
that the length of the space occupied by the four cheek- 
teeth is somewhat less. 
Oroizet Collection. Purchased, 1848. 
25100. Part of the right ramus of the mandible, containing the four 
cheek-teeth ; from the Lower Miocene of Cournon. 
Croizet Collection. Purchased, 1848. 
25098. Fragment of the palate, containing some of the cheek-teeth ; 
from the Lower Miocene of Cournon. 
Crowzet Collection. Purchased, 1848. 
27674. Fragment of the left maxilla, containing the first three 
‘ Comptes Rendus, vol. viii. p. 206 (1839). 
* Zool. et Pal. Frangaises, 1st ed. vol. ii., explanation of pl. xlvii, (1848-52). 

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