454 SPEKMOPHJLUS. 



much. The post orbital processes are very much hooked backwards 

 in a Russian skull of S. musogaricus, but they are not so divergent or 

 spread out as in the fossil. The palatine slits are very large in the 

 drawing of the fossil.' 



Extract from Letter to M. Lartet, June 27, 1864. — ' With regard to 

 the Spermophilus : there are three species in the British Museum , the 

 lower jaws of which are nearly of the same size, and, with certain 

 differences, very much alike in form. These are : S. concolor, S. 

 Eversmanii, and S. erythrogenys. But unfortunately, the number of 

 specimens of each is too limited to determine what the range of variety 

 of form is in each. On comparing the materials, I found the cave 

 Spermophilus of the Mendip hills to come nearest to S. Eversmanii 

 and S. erythrogenys ; but most closely to resemble the latter. I there- 

 fore called it S. erythrogenoides. The lower jaw from M. Desnoyers 

 (Montmorency) appears to me to resemble the Mendip Cave form very 

 closely. I believe them to be the same. But the Spermophilus from 

 the gravel of Salisbury is considerably larger, with a very broad 

 ascending ramus, a long neck to the condyle, and other differences. 

 Possibly there are two fossil species in England ; and neither of them 

 the " Souslik," i.e. S. concolor. The name of S. erythrogenoides is 

 provisional.' 



