MURIDiK. ARCTOMYS. 219 



The Columbian Ground Squirrel. Spermophilus douglasii. 

 Baird, Mamm. N. America, p. 309. pi. 45. fig. 1 (skull), 1859. 



Harris's Squirrel. Spermophilus harrisii. 

 Baird, Mamm. N. America, p. 313. pi. 47. fig. 3 (skull), 1859. 



The Souslik. Spermophilus concolor. 



Ciiv., Oss. Foss. v. p. 29. pi. 1, fig. 25 (teeth).— Owen, Odont. pi. 105. 



fig. 3 (a, .young — b, old molars). — Blasius, Faun. Wirb. Deutschl. 



p. 275. fig. 155 (skull), 1857. 

 Mus citillus, F. Guv., Dents des Mamm. p. 160. no. 55 (dentition), 



1825. — Pallas, Nov. Spec. Glires, tab. 26. fig. 9 a, b (ossium penis), 



tab. 27. fig. ix. 11* (skull), 1778. 

 Arctomys citillus, Blainr., Oste"og. G. Arctomys, pi. (skull). 

 Arctomis citillus, F. Ctiv., Mem. du Mus. ix. p. 293. pi. 15. figs. 1, 2 



(skull). 



a, b. *Skulls. Moldavia. 



Spermophilus eversmanui. 



a, b. *Skulls. Altai Mountains. 



The Seek -Seek. Spermophilus parryii. 



*a. Skull. N. America. Presented by J. Rae, Esq. 

 *b. Skull. N. America. Presented by Sir G. Back. 

 c, d. Skeletons (imperfect). N. America. Presented by J. Rae, Esq. 



Franklin's Marmot. Spermophilus frankliriii. 

 *a. Skull. 



CYNOMYS. 

 The Missouri Prairie Dog. Cyuomys ludovicianus. 

 Baird, Mamm. N. America, p. 331. pi. 47. fig. 2 (skull), 1859. 



The Short-tailed Prairie Dog. Cyuomys gunrrisonii. 

 Baird, Mamm. N. America, p. 335. pi. 47. fig. 4 (skull). 



ARCTOMYS. 



Teeth :— Incisors ~ ; Molars j^ ;=22. 



The Quebec Marmot or Weenusk. Arctomys empetra. 



Arctomys monax, Gmel, Syst. Nat. i. p. 142, 1788. — Baird, Mamm. 

 N. America, p. 339. pi. 49. fig. 1 (skull), 1859. 



Cervical vertebra? 7 



Dorsal 12 



