26 



Measurements of a skull of Synaptomys cooperi (No. 6915, Mas. 

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

 of nasals) 1.14; greatest Z3'gomatic width, 0.72; least width (at 

 interorbital constriction) 0.15; width of rostrnm, 0.25; intermas- 

 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. 



]. Synaptomys cooperi, Baird. 



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

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



Arvicola {Synaptomys) gosni, Bd., Mus. S. I. (labels of Kansas speci- 

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



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

 ville, Indiana, i/ay/jio/icZ. Soutli Illinois, ^(3M?n'co<^. Benton Co., 

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

 ley, Oregon, Kennerly. Nulato, Alaska, Dall. 



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. 



Stn. Mas., sp., et Arvicola, sp., Auctt. antiq. — IlypudcBus, lUiger, 1811, 

 partim, (includes Mus lemmus, ampMbius, etc.). — Myodes, Pall., Zoog. 

 R. A. i. 1811, 173, in part (includes J./'fl»coZa, and thus about coexten- 

 sive with his Mures cunicularii oi 1778). — Lemmus, Linck (fide Bd. 

 In part; includes Arvicola.) — OeorycTius, Rich., F. B. A. 1839 ; and 

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

 of an entirely different family. 



Ohs. Tlie cliars. of this genus should unquestionably be so 

 drawn as to exclude C'u?^^CM/t^s, which latter, although also a " lem- 

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

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



