194 PROCEEDINGS OF THE ACADEMY OP 



Measurements of a skull of Synaplomys cooperi (No, 6915, Mus. 

 S. I., Kansas, B. F. Goss ). Total length (occip. protub. to end 

 of nasals) 1.14; greatest z^'gomatic width, 0.12; least width (at 

 intei'orbital constriction) 0.15; width of rostrum, 0.25; interraas- 

 toid width 0.58 ; interparoccipital width 0.37 ; height opposite and 

 including last molar, without lower jaw, 0.45 ; length of upper 

 molar series 0.30 ; length of extra-alveolar portion of upper inci- 

 sors 0.24 ; length of rostrum 0.25 ; tip of under incisors to apex 

 of coronoid 0.62, to back of condyle 0.79, to end of descending 

 process 0.81; length of under molar series 0.28; of extra-alveolar 

 portion of under incisor 0.25. 



1. Synaptomys cooperi, Baird. 



Myodes {Synaptomys) cooperi, Bd., M. N. A. 1857, p. xliv. 

 Synaptomys cooperi, op. cit. 558, in text. 



Armcola {Synaptomys) gossii, Bd., Mus. S. I. (labels of Kansas speci- 

 mens which, however, are inseparable from the types). 



Hab. Middle and Western United States and northward. Brook- 

 ville, Indiana, Haymond. South Illinois, Kennicott. Benton Co., 

 Minnesota, Garrison. Neosho Falls, Kansas, Goss. Skagit Val- 

 ley, Oregon, Kennerly. Nulato, Alaska, Ball. 



Dimensions (average of several, alcoholic, from Kansas). Nose 

 to eye 0.45 ; to ear 0.95 ; to occiput 1.20 ; to root of tail 3.50 (from 

 3.00 to 4.00 range of the whole series 2.90 to 4.30) ; tail verte- 

 brae 0.65 (from 0.51 to 0.75) ; tail, with hairs, 0.75 ; fore foot 0.40 ; 

 hind foot 0.70 ; ear 0.35. 



Eigliteen specimens, dry and alcoholic, examined from the above 

 localities. 



Genus VIII. MYODES, Pall., emend. 



Syn. Mm, sp., et Arvicola, sp., Anctt. antiq. Ilypudmis, Illiger, 1811, 

 partini (includes Mus lemmus, amjMbius, etc.). Myodes, Pall., Zoog. 

 R. A. i. 1811, 173, in part (includes Arvicola, and thus about coexten- 

 sive with liis Mures cunicularii of 1778). Lemmus, Linck (fide Bd. 

 In part; includes Arvicola.) Georychus, Rich., F. B. A. 1829 ; and 

 And. and Bach., 1854 (includes Cuniculus). Not of Illiger, which is 

 of an entirely different family. 



Ohs. The chars, of this genus should unquestionably be so 

 drawn as to exclude (7(<m'cu/s, which latter, although also a " lem- 

 ming," is quite as widely separated as the other genera of Arvicol- 

 inse are. Being based upon a long and well-known animal, the 



