Osgood — Thirty New Mice of the Genus Peromyscus. 63 



species. In this respect it approaches a similar condition frequently 

 foniid in specimens of the vit'lniutpltri/s type. It is easily distinguished 

 from melanopJiryx by tlie absence of any definite supraorbital ridge and 

 I)y its larger audital bullfe. Its relationship to diffi.cil.lt< is by no means 

 remote, but its skull ditiers in the same respects as that of fclipctiKix. 



'Specimens examined. — Total number, 65, from localities in Mexico as 

 follows : Oaxaca, Coixtlahuaca, 16, Marques, 5, Tamazulapam, l.S ; Puehla, 

 Chalchicomula, 9 ; Tlaxcala, Apixaco, 2 ; Vera Cruz, Maltrata, 5, Perote, 1 5. 



Peromyscus bullatus sp. nov. 



Tiijir from Perote, Vera Cruz, Mexico. Adult female, No. 54,405, U. S. 

 National INIuseum, Biological Survey Collection, June .'», 189;5, E. W. 

 Nelson and E. A. Goldman. 



Characters. — Related to P. Iruei and P. difflcilis ; audital bullw greatly 

 inflated, larger than in any other known species of the genus; external 

 ears very large ; tail shorter than head and body. 



Color. — Very similar to that of P. truei, but richer, more tawny ; sides 

 and ground color of upper parts tawny ochraceous; middle of back with 

 considerable dusky producing a broccoli brown effect; top of head and 

 nose broccoli brown ; sides of liead between base of ear and eyedistinctlj' 

 grayish; a narrow dusky orbital ring; under i)arts pure creamy white; 

 feet white with a dusky patch on ankle; tail bicolor. 



Skull. — .Similar in general to that of P. truei ; smaller than in P. difficilis ; 

 audital bnllte very much inflated, actually as well as relatively larger than 

 in any other known species of the genus; braincase rounded and some- 

 what inflated, much as in Iruel ; interorbital constriction relatively wider 

 than in difficilis; nasals anil palatine slits rather long; molar teeth large, 

 actually larger than those of truei and nearly equalling those of difficilis. 



.Measurements. — Type: Total length, 200 ; tail vertebra?, 93 + ; hind foot, 

 23; ear from notch (measured dry), 25. Skull of type: Greatest length, 

 28.9; basilar length of Hensel, 22; zygomatic width, 14.5; interorbital 

 constriction, 4.5; interparietal, 10x3; nasals, 10.4; bony palate, 4.2; 

 palatine slits, 5.8 x 2 ; diastema, 8.3 ; postpalatal length, 10 ; upper molar 

 series, 4.3; greatest diameter of audital buUee, 6.5. 



Remarks. — The relationships of this rather remarkable mouse are 

 clearly with P.lruei&niX P. difficilis. Its short tail * and light color are 

 suHicient to distinguish it from difficilis at a glance, and its enormous 

 audital bullae separate it at once from truei. The external ears are also 

 very large, slightly exceeding those of difficilis as well as of all other 

 species. There is only the one specimen in the collection, in spite of the 

 fact that its habitat is in the state of Vera Cruz, where reasonably 

 thorough collecting has been done. 



*The tail of the type is not quite perfect, having lost the extreme tip, 

 but it is very evident that it was naturally much shorter than that of 

 difficilis. 



V— Pitiif. Rioi.. Sue. Wash. Vol. XVII, l!i(i4. 



