74 Osgood — Thirty New Mice of the Genus Peromyscns. 



Measuremenls.— Type {not quite aduM): Total length, 241 ; tail vertebrae, 

 125; hind foot, 27. Ad. c? from Totontepec, Oaxaca: 262; 132; 30. 

 Skull of type: Greatest length, 31. B; basilar length of Hensel, 24.3; 

 zygomatic width, 15.2; nasals, 12; interorbital constriction, 5.4; pala- 

 tine slits, 7.3; upper molar series, 5. 



Remarks. — This mountain species is about the size of P. m. toUmicpccus, 

 with which it ranges to some extent, but is much more closely related 

 to megalopsawd aurilus, as indicated by its cranial characters and its more 

 bristly tail. Its most diagnostic character, however, is the extent of 

 dusky brownish on the fore feet, which is almost unique. In" some 

 specimens the ends of the toes and the outer side of the metacarpus are 

 the only parts not occupied by the dark color. The pelage is long and 

 lax like that of many other mountain forms. The type was taken at 

 8000 feet altitude. Five additional specimens from Totontepec on the 

 north slope of the same mountain at 6500 feet altitude are also in the col- 

 lection, p. lepturus, which also occurs on Mt. Zempoaltepec, is smaller 

 than melanocarpus and differs in numerous cranial characters, among the 

 most obvious of which are : Braincase smaller and narrower, interorbital 

 constriction narrower, nasals shorter, supraorbital beads less develo})ed. 



Peromyscus altilaneus sp. nov. 



7}//)f from Todos Santos, (luatemula (altitude 10,000 feet). Adult male, 

 No. 76,856, U. S. National Museum, Biological Survey Collection, Decem- 

 ber 30, 1895, E. W. Nelson and E. A. Goldman. 



Cli<(ra€lers. — Similar to P. melanocarpus, but smaller and with sliorter and 

 less hairy tail ; fore feet entirely white; hind feet with much more white 

 tlian in melanocarpus ; skull slightly smaller and more slender; similar to 

 guatemalensis but much smaller. 



Color. — As in melanocarpus, hut tail blotched with yellowish white 

 below, much as in me.ricanus : fore feet and part of forearm white; hind 

 foot with a V-shaped dusky mark extending from ankle al)out half way 

 to the base of the toes, remainder of foot white ; pectoral spot strongly 

 developed in tyi)e. 



Skull. — Similar to that of rnelanocarpus, hut slightly smaller throughout ; 

 nasals relatively more expanded anteriorly ; braincase slightly higher and 

 more inflated and rostral region more depressed ; anterior palatine foram- 

 ina shorter; infraorbital plate very nari-ow. 



Measurements. — Ty])e : Total length, 228; tail vertebra', 115 ; hind foot, 

 28. Skull: Greatest length, 31 ; basilar length of Hensel, 24; zygomatic 

 width, 14.6; interorbital constriction, 5; nasals, 11.5; bony palate, 4.8; 

 palatine slits, 6 x 2.7; diastema, 8.2; postpalatal length, 11.2; upper 

 molar series, 4.(). 



Remarks. — The type of this species is the only specimen known at pres- 

 ent. Its only close relationship is with P. mclanocai-pus, to which it is 

 very similar except in regard to the color of the wrists and fore feet. 

 From P. lepturus it difiers in darker color, strongly developed i)ectoral 



