402 



^BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



REITHRODONTOMYS MEGALOTIS DESERTI Allen. 

 DESERT HARVEST-MOUSE. 



Reithrodontornys megalotis deserii Allen, Bull. Am. Mus. Nat. Hist., VII, p. 127, May 

 21, 1895 (original description). — Miller and Rehn, Proc. Bost. Soc. Nat. Hist., 

 XXX, No. I. Dec. 27, 1901, p. 98 (Syst. Results Study N. Am. Mam. to close of 

 L900). 



[Reithrodontornys megalotis] pattidus, Elliot, Field Col. Mus., Zool. Ser., 11, 1901, 

 p. 152 (pari) (Synop. Mam. N. Am.). 



[Rt ithrodontomys lonfficaudus] pattidus, Elliot, Field Col. Mus., Zool. Ser., IV, 1904, p. 

 622 (pari I (Mam. Mid. Am.). 



Type-locality. Oasis Valley, Nye County, Nevada. 



Geographical range.— rFrom southern Nevada and Inyo County, Cali- 

 fornia, south to the mouth of the 

 Colorado River, Sonora, and 

 Lower California. 



Description. — Slightly smaller 

 than B. megalotis, with a longer 

 tail; color paler: pelage, shorter 

 and harsher. (Fig. 115.) 



Measuremt ids. — Averageof 10 

 adult males: Total length, 140 

 mm.; tail vertebra?, 75; hind 

 foot, 18; ear from crown, 11.35. 

 Average of 10 adult females: 

 Total length, 144 mm.; tail ver- 

 tebras, 75; hind foot, 17.7; ear 

 from crown, 11.7. 



Iii marks. — Forty specimens 

 taken along the Colorado River 

 during March, 1894, exhibit but 

 slight individual and age varia- 

 tions. Adults are all pure white 

 below , excepting a few thai have 

 clay-colored pectoral patches. 

 They vary some in the intensity 

 of the yellowish color of the up- 

 per surface. Those that are 

 immature 1 are less yellowish than 

 drab-gray above, grayish white 



FIG. 115.— REITHRODONTOMYS M. DESERTI. O, iiind- 

 foot; b, forefoot; c, tail; d, outer lateral 



VIEW OF LOWER MOLARS; e, SAME OF UPPER 

 MOLARS; f.nmWXS (M' OHPER MOLARS; 3, CROWNS 



of lower molars; i), lower incisors; /, upper 

 incisors. 



and half -grown voung are 



adults 



below. A smaller series from Sallon and -New rivers, on the Colorado 

 Desert, taken during April, closely resemble those from the Colorado, 

 but are a shade paler and more gravis'). 



lam indebted to Dr. C. Hart Merriam for the opportunity of exam- 

 ining a large series of topotypes and the type of this subspecies from 

 Oasis Valley, Nye County, Nevada. These differ from those taken 

 by ourselves along the Colorado River, from Yuma to the Gulf of Cali- 

 fornia, and thence westward across the Colorado Desert, in being of a 



