SUPPLEMENT. 323 



Genus MYODES, Pallas \ 

 Including Cuniculus, Wagler ^ 

 Molars as in Arvicola, but sole of feet hairy. 



MvotitS torq[uatuj^, Pallas \ 



Syn. Mus toi'quatus, Pallas ^. 



Arvicola ambiguus (pt. i. p. 231). 

 Ai'vicola gulielmi (pt. i. p. 231). 

 Lemmus torquatus, Sanford °. 

 Cuniculus to7'quatus, auct. 



Hah. Europe. 



The specimens entered in pt. i. p. 232 under the name of Arvi- 

 cola ambiguus belong to this species ; see Alston, * Proc. Zool. Soc' 

 1874, p. 460. 



Family GEOMYID^. 



Dentition : — I. ^, C. ^, Pm. \, M. |. The molars may be either 

 rooted or rootless. All the genera are American. 



Genus ENTOPTYCHUS, Cope^ 

 Crowns of the cheek-teeth prismatic, and in the young presenting 

 a deep enamel-fold, which eventually wears into an islet ; no roots to 

 the teeth ; the cranium has no vacuities ; and the limb-bones resemble 

 those of the existing Thomomys. Five species have been recorded. 



Entoptychus crassiramis, Cope ^. 



The length of the cranium is 0,046. The superciliary ridges are 

 thickened, and the premolar is widened at the base. 

 Hah. North America. 



M. 2567. Middle portion of the cranium, showing the three true 

 molars of the left side; from the Miocene of the White River, 

 Colorado, U.S.A. A similar specimen is figured by Cope in 

 the ' Yertebrata of the Tertiary Formations of the West ' 



^ Zoogr. Eosso-Asiatica, yoI. i. p. 173 (1811). 



2 Isis, 1832, p. 1220. 



3 Nov. Spec. Glirium, p. 77 (1778).— ilfws. * Loc. cit. 

 5 Quart. Journ. Geol. Soc. vol. xxyI. p. 125 (1870). 



« Proc. Amer. Phil. Soc. vol. xviii. p. 64 (1879, vol. dated 1880). 

 ^ Ibid. p. 65. 



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