Dan RODENTIA. 
Geraes, Brazil. In the absence of figures, it is impossible 
to say to which of the four species established by Gervais 
and Ameghino these specimens belong. 
Claussen Collection. Purchased, 1845. 
Genus ISSIODOROMYS, Blainville* (ew Croizet). 
Cheek-teeth rootless, with open re-entering enamel-folds dividing 
their crowns into heart-shaped lobes; the subsidiary folds only 
represented here and there by a minute enamel-island. There has 
been considerable doubt as to the serial position of this genus. It 
was placed by Alston among the Theridomyide; but it is very 
closely allied to the next genus, which Schlosser considers allied to 
Dolichotis. 
Issiodoromys pseudanzma, P. Gervais’. 
Syn. Palanema antiqua, Pomel ’. 
Hab. France. 
27768. The palate, with the cheek-teeth ; from the Lower Miocene 
of Perignat, near Issoire (Puy-de-Dome), France. 
Croizet Collection. Purchased, 1848 
34901. The upper cheek-dentition; from the Lower Miocene of 
Sauvetat (Puy-de-Dome). 
Bravard Collection. Purchased, 1882. 
34902. The nearly complete right ramus of the mandible; from the 
Lower Miocene of Sauvetat. 
Bravard Collection. Purchased, 1852. 
97691. Fragment of the lefi ramus of the mandible; from the 
Lower Miocene of Perignat. 
Croizet Collection. Purchased, 1848. 
96717. Part of the left ramus of the mandible, containing all the 
cheek-teeth ; from the Lower Miocene of Cournon (Puy- 
de-Déme). Croizet Collection. Purchased, 1848. 
M. 1495. Fragment of the right ramus of the mandible, containing 
the anterior cheek-teeth; from the Upper Eocene of 
Caylux (Tarn-et-Garonne), France. This specimen is 
indistinguishable from No. 26717. The species is not _ 
recorded by Filhol or Schlosser from the phosphorites. 
Purchased, 1884. 
1 Comptes Rendus, vol. x. p. 932, note (1840). 
2 Zool. et Pal. Frangaises, lst ed. vol. i. p. 27 (1848-52). 
3 Catalogue Méthodique, p. 41 (1853). 
