EUROPEAN REDBACKED MICE 99 



Geographic distribution. — Lowlands between the Alps and Jura. 

 Ge?icral characters. — Skull broader and audital bullae larger than 

 in any of the other known races of Evotomys hercynicus. Size 

 rather large (hind foot 19 (i8), total length 145) ; tail forming 31-33 

 percent of total length. Winter pelage : dorsal red area diffuse, hazel, 

 micch inter7nixed -with gray; belly slightly washed with buff; tail 

 nearly black above. 



Color. — Summer pelage not known. Winter pelage : red dorsal 

 area very diffuse and ill defined, extending from eyes to base of tail, 

 but not widely spreading over sides. In color it is hazel, slightly 

 darkened by black tipped hairs, and intermixed with broccoli-brown 

 or ecru drab (the subterminal color bands) and grayish white. The 

 brown and gray is'always noticeable and occasionally almost in excess 

 of the red. Sides and cheeks broccoli-brown or ecru drab, incon- 

 spicuously sprinkled with black. Face slightly darker than cheeks. 

 Belly whitish gray washed with cream buff and darkened by the 

 slaty underf ur. The buff wash is variable. It is nearly absent in two 

 specimens among eighteen, and in a few it is considerably more heavy 

 than usual, spreading noticeably over cheeks, face and sides. Tail 

 very conspicuously bicolor, blackish above, buffy white beneath. Feet 

 white. Ears like dorsal stripe. A tuft of whitish hairs springs from 

 near posterior base of conch. This tuft forms a distinct spot in some 

 specimens. 



Skull. — The skull of Evotomys hercynicus helveticus is slightly 

 larger than that of the other races, the braincase is less elongated and 

 the audital bulljE are larger. The differences are not easily described, 

 but on comparison of series of skulls they at once become apparent. 



Measurements of skull of type : greatest length 24 ; basal length 

 22.2; basilar length 21; zygomatic breadth 13.6; mastoid breadth 

 1 1.8; greatest breadth of braincase above roots of zygomata 11.4; in- 

 terorbital constriction 4 ; nasals 7 ; incisive foramen 5 ; diastema 6.B> ; 

 palatal length 1 1 ; occipital depth (at front of basioccipital) 7 ; fronto- 

 palatal depth (at middle of molar series) 6.2; mandible 15; maxil- 

 lary toothrow (alveoli) 6; mandibular toothrow 5.6. 



Measurements. — Average of sixteen topotypes : total length 13S; 

 tail vertebrae 44.6; hind foot with claws 19.2; hind foot without 

 claws 17.9. For details see table, page 107. 



Specimens examined. — Twenty, from the following localities : 

 France, Montauban (near Geneva, Switzerland) 17; Switzerland, 

 Vand (near Lausanne) i (skull) ; St. Gallen, 2. 



Remarks. — This animal is so well differentiated from true Evotomys 



Proc. Wash. Acad. Sci., July, 1900. 



