30 NORTH AMERICAN FAUNA. 



sides. White of lower parts so strongly suffused with ochraceous 

 that the white is almost obsolete, appearing only 011 lower parts of 

 forelegs aud between thighs ; hind legs ochraceous all arouud ; sides of 

 throat deeper ochraceous than remainder of lower parts; feet yellowish 

 white; tail yellowish-white below and grayish above. A specimen 

 from Point Reyes, in the collection of Dr. C. Hart Merriam, about one- 

 fourth grown, " has the upper parts almost uniform deep ocbraceous 

 yellow, with only the faintest trace of the dorsal area." 



Cranial characters. Skull rather small; rostrum short and consider- 

 ably deflected; nasals very narrow anteriorly; greatest zygomatic 

 breadth on plane of middle molars; zygomata rather light, the maxil- 

 lary portion meeting nearly at right angles to main axis of skull; pro- 

 cess on lower border of maxillary arm of zygoma very pronounced and 

 nearer autorbital foramen than in any other species. Brain case high 

 and rather globular in shape; interorbital constriction narrow; inter - 

 pterygoid fossa narrow and shallow; incisive foramina rather small 

 and evenly" elliptical in shape; audital bulla? small aud rather near 

 together; upper incisors slender and more projecting than usual; man- 

 dibular symphysis short. 



Measurements. The type measures : Total length, 220; tail vertebra', 

 127; hind foot (dry), 30. Skull (type) : Basilar length, 19; zygomatic 

 breadth, 12; mastoid breadth, 10.6; iuterorbital constriction, 4; incisor 

 to postpalatal notch, 8.5; foramen magnum to postpalatal notch, 7.1); 

 fronto-palatal depth at middle of molar series, 6.2. 



General remarks. Zapus orarius appears to be a very well-marked 

 species requiring close comparison with no other known form. The 

 type has the lower parts more intensely suffused with the color of the 

 sides than any other specimen of the genus that I have seen. A speci- 

 men from Mad River, Humboldt Couuty, resembles the type very closely, 

 and another from Eureka, without a skull, undoubtedly belongs to this 

 species. The latter is suffused beneath with ochraceous, though to a 

 lesser extent than the type. The skull of the type bears a slight resem- 

 blance in some respects to that of Z. pacificus, but the differences are 

 so great that unless the type specimen is abnormal orarius can not be 

 considered closely related to pacificus. Much additional material is 

 needed to clear up satisfactorily the relationships of these and other 

 forms from this region. 



Specimens examined. Total number, 4, from the following localities: 



California: Eureka, 1; Mad River (Carson's Camp), 1; Point Reyes (type 

 locality), 2. 



ZAPUS PACIFICUS Merriam. Pacific Jumping Mouse. 

 Zapus pacificus Merriam, Proc. Biol. Soc. Wash., XI, p. 104, April 26, 1837. 



Type locality. Prospect, Eogue River Valley, Oregon. 

 Geographic distribution. Interior valleys of southwestern Oregon 

 and northwestern California; limits of range unknown. 



