J36 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



D DISTRIBUTION AND HABITS OF PHENACOMYS 



LONGICAUDUS TRUE 



I Distribution 



1 IN TIME 



No fossil material whatever referable to the genus is 

 known. "Arvicola" intermcdius Newton (see Miller, 1896, 

 pp. 75, 76) from the late Pliocene Forest Bed of Norfolk, 

 England, referred to Phcnaconiys by Nehring, has recently 

 been associated with a number of other fossil forms in the 

 genus Mimomys Forsyth Major. As stated by Hinton with 

 reference to the genus Mimomys (1914, p. 474), "its mem- 

 bers are amongst the earliest microtines in Britain, having 

 been detected in the late Pliocene Norwich Crag." Conse- 

 quently this genus is of great interest, although its general- 

 ized enamel pattern with reentrant angles approximately equal 

 shows that it cannot be closely related to Phenacomys. 



2 IN SPACE 



Specimens have been actually taken as follows : In Ore- 

 gon: Marshfield, Coos County; Meadows, Lane County; 

 Eugene, Lane County. In California: Chaparral Mountain, 

 above Maplecreek Post Office, near "Big Bend," Mad River, 

 Humboldt County; Cuddeback, Humboldt County; Carlotta, 

 Humboldt County; Mendocino City, Mendocino County; 

 Lierly's Ranch, four miles south of Mt. Sanhedrin, Mendo- 

 cino County. 



There is little doubt that the tree mouse occurs at many 

 other localities in this general region. Mr. Aurelius Todd, 



Fig. 4— KNOWN RANGE OF PHENACOMYS LONGICAUDUS, 



WITH RECORD STATIONS OF ALL THE PHENACOMYS 



KNOWN TO HAVE BEEN TAKEN IN CALIFORNIA 



AND OREGON. 



(See map on opposite page.) 



H Localities where Phenacomys orophilus has been collected 



^^ Localities where Phenacomys albipes has been taken. 



Q Localities where Phenacomys longicaudus has been collected. 



/Oj Localities where Phenacomys longicaudus is known to occur, but 

 ^^ no specimens collected as yet. 



Area within which Phenacomys longicaudus is known to occur. 



