MICRODIPODOPS. PEROGNATHUS. 241 



366. megacephalus. ^MicrodipoJops), Merr., N. Am. Faun., 1S91, 

 Pt. 5, p. 116. 



Type locality. Halleck, Nevada. 



Geogr. Distr. Central Nevada. 



Genl. Char. Size small; tail not crested at tip, slightly exceed- 

 ing the length of head and body. Hind feet long, furred; ears cov- 

 ered with fur. Other characters those of the genus. 



Color. Above yellowish brown, mi.xed with black and tinged 

 with olive; sides from nose and thigh pale ochraceous. Beneath 

 white, fur plumbeous at base, except on throat and breast, which are 

 white to the roots of hairs. Feet buffy white. Tail, basal two-thirds 

 like back, rest blackish; under sides pale buffy ochraceous The 

 usual black crescent on face at base of whiskers and buff patch be- 

 hind the ears. 



Measurenients. Total length, 150; tail vertebrcX-, 80; hind foot, 

 24; ear from crown, 6. 



Sub. Fam. II. Heteromyinae. 



C. H. Merriam. Revision of the North Anu-rican Poik^t .^fic,-. N. 



Am. Faun., No. i, i88g, p. i. 

 W. H. Osgood. Revision of the Pocket Mice of the genus J'erog- 



nothiis. N. Am. Faun., No. 18, igoo. 



(>4. Perognathus. 



I- —■' P- 1^; M. ^; = 20. 



Perognathus. Wied., Nov. Act. Acad. Cars. Leop. Carol., 1839, 



xix, p. 369. Type F. fascial us, Wied. 



.■' Cricetodipus. Peale, Rep. Mamm. & Ornith. U. S. Expl. 



Exped., 1848, p. 53, pi. 13, fig. 2. Type P/ parvus, Peale. 



Abromxs. Gray, Proc. Zool. Soc, 1868, p. 202. Type P. lordi. 



Gray. 

 Octognosis. Coues., Proc. Acad. Nat. Scien. Phil., 1875, p. 305. 



Type P. Jlarus, Baird. 

 Chaetodipus. Merr., N. Am. Faun., No. i, iS8g, p. 5. T)pe 



P. hispidus? Baird. 

 Skull depressed and flat above, nasals lengthened, projecting be- 

 yond incisors; mastoids less developed than those of the species of Dipi- 

 domx'inae, and in certain species do not project bejond plane of occi- 

 put; zygomata much as in ordinary rodents. Occiput not emarginate; 

 molars rooted; no pit between last lower molar and coronoid proc- 

 ess; tail moderate; soles naked or sparsely haired. 



