SACCOMYIDiE— rEEOGNATOIDIN^a— C. TARVUS. 510 



CRICETODIPUS PARVUS, Baird (and Peak?). 



Least Pocket-mouse. 



T Cricetodipus parvus, Peale* U. S. Expl. Exped. 1848, 53, " pi. 13, f. 2 ".— Giebkl, Siiug. 1855, 600 (compiled 

 from Peale).— Gray, P. Z. S. 1808, 20:1 (compilation of doubtful references). 



? I'erognalhus (Cricetodipus) parvus, Aud. & Bach., Q. N. A. iii, 1854, 328 (copied from Peale). 



Perognalhus parvtw, Baird, M.N. A. 1857,425 (based on a specimen from King's River, Cal., doubtfully re- 

 ferred to C. parvus of Poalo).— Baikd, P. K. K. Kep. x, 1859, Williamson's Route, 82 (same 

 specimen). 



Cricetodlpus parvus, Coues, Proc. Phila. Acad. 1875, 303 (monographic). 



Otognosis longimembris, Coues, Proc. Phila. Acad. 1875, 305 (provisional name). 



Diagnosis. — Quite like C. Jlavus ; tail and feet longer. Hind foot 0.70 

 or more, one-third or more as long as head and body. Tail decidedly longer 

 than head and body; the vertebrae about 2.50 inches to a body of 2.00. 



Habitat. — United States, west of the Rocky Mountains. California, 

 Utah (and 1 Oregon, Peale). 



Of this supposed species, I have two specimens additional to the 

 material in Professor Baird's hands in 1857. One of them, alcoholic, in good 

 preservation, enables me to give the dimensions with accuracy. 



(No. 9856, Mus. Smiths. Inst. 9 ; Fort Tejon, Cal , J. Xantus.) Nose 

 to eye 0.45, to ear 0.70, to occiput 0.90, to tail 2.00 ; tail vertebrae 2.50, with 

 hairs 2.75 ; fore foot 0.25 ; hind foot 0.70 ; ear above notch 0.25. 



Another specimen, from Utah (No. 439, Mus. Smiths. Inst., formerly 

 referred by Baird to C Jlavus), seems to belong to C. parvus; the hind feet 

 are still longer — nearer 0.80 than 0.70 — and the tail at least as long as in 

 No. 9856. 



A third specimen, recently collected by Mr. H. W. Henshaw in Califor- 

 nia, seems to be unquestionably referable to this species. These three are 

 all I have seen. 



As well as can be judged from the insufficient material before me, this 

 species does not differ materially in color from C. jlavus ; and in fact the only 

 diagnostic characters at present appreciable are the greater length of the hind 

 feet and tail. There is, however, a decided difference in these respects. 

 Further material will be required to confirm the specific distinctness here 

 accorded, or to show that the two supposed species intergrade. Leaving this 

 matter, we may turn to the history of the species, some points of which call 

 for remark. 



In the first place, it is not certain that the animal called parvus by Baird 



