FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. i. 



These examples agree very well with Dr. Merriam's description 

 of his type from Berkeley, California. 



FAMILY 

 40. Zapus alleni. sp. nov. 



General characters : Size large, tail very long, ears medium, 

 partly concealed at base. 



Color: Upper part of head and back brownish black, lined with 

 deep fulvous ; sides of head, flanks, front of fore legs, thighs and 

 sides of the rump bright orange yellow, sparingly lined with 

 black, presenting a strong contrast to the back, in this respect, 

 however, resembling some other species of the genus. Ears like 

 the top of head, with rusty margins. Entire under parts, with 

 hands, hind legs and feet, pure white. Tail bicolor, brown above, 

 white beneath, and white at tip, similar to Z. insignis, Miller. 

 Nose brown ; whiskers, longer than the head, white. 



Cranial and dental characters: The skull, when compared with 

 that of Z. trinotatus montanus, possibly its nearest ally, differs very 

 considerably. The superior outline from the tip of the nasals to 

 the interparietal is much more curved, and descends* rapidly 

 from the fronto-parietal suture to the occipital outline ; that of the 

 species compared hardly curving at all. The cranium is longer 

 and narrower in proportion to its length, and there is little, if 

 any, antorbital constriction of the frontals, these having their 

 outer edges nearly straight to their junction with the nasals. 

 These last are broad, being three mm. wide for their entire 

 length, and rounded at the anterior extremity. The palate is 

 wider than that of Z. t. montanus, and the pterygoids are straighter, 

 causing the pterygoid fossa to be wider posterially. The palatal 

 notch is inclined to a point, much less rounded than that of the 

 subspecies compared, and not wider than the fossa, which 

 last, in Z. t. montanus, is constricted midway its length. The 

 auditory bullae are of an entirely different shape, being relatively 

 much shorter antero-posteriorly than transversely, and altogether 

 much smaller. The basi-spenoid and basi-occipital, especially 

 at their junction, are both relatively of greater width. The 

 occipital condyles are broader and more rounded, causing the 

 plane of the basi-occipital to descend anteriorly, that of the sub- 

 species compared being almost flat. The upper tooth row is 40 

 mm. in length, while that of Z. t. montanus is 45 mm., and the 

 premolar and last molar are smaller and more rounded. The 

 lower jaw presents no especial differences. Total length of skull 



