Il8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 69 



hanging banks and in other sheltered places frequented by them while 

 in search of food on the ground. Several were caught in traps set 

 close to the palm-thatched camp ; one was taken under my cot where 

 it may have been attracted by some of the provisions. A pocket 

 mouse held by the tail in a trap and still alive when removed set its 

 teeth into clothing and tried to bite my hand. The rather dense under- 

 growth here consists largely of small palms and ferns. The only 

 other small rodent which was found to occur in similar numbers in 

 the same forest was another representative of a Middle American 

 group, the Mount Pirre mouse, Peromyscus pirrensis. The lower 

 slopes of the mountains at 2,000 feet are inhabited by Heteromys 

 australis consents, a form of a species mainly South American in 

 distribution. The latter is similar to H. d. crassirostris in size and 

 general external appearance, but the slender hairs among the blackish 

 dorsal bristles are paler in color and the cranial characters indicate 

 that the two forms of the genus which here occur so near together 

 are specifically distinct. Anthony (1916, p. 370) records taking a 

 specimen of crassirostris at 5,200 feet on Mount Tacarcuna. 

 Specimens examined: Mount Pirre, 23; Mount Tacarcuna, I. 1 



Genus LIOMYS Merriam. Pocket Mice 



The general color of the upperparts in the genus Liomys is more 

 grayish, less blackish than in the genus Heteromys, and the sole of 

 the hind foot is hairy from near the posterior tubercle to the heel 

 (naked to heel in all Panama forms of Heteromys). Generic dis- 

 tinction is shown in the skull, the dentition being simpler, the 

 interpterygoid fossa broadly U-shaped instead of V-shaped, and the 

 angle of the mandible much more strongly everted. 



LIOMYS ADSPERSUS (Peters) 



Peters' Spiny Pocket Mouse 



Heteromys adspersus Peters, Monatsber. k. preuss. Akad. Wissensch. 

 Berlin, p. 356, with pi., May, 1874. Type locality, City of Panama.' 



In general external appearance Peters' spiny pocket mouse is not 

 very unlike Heteromys desmarestianus zonalis which also inhabits 

 the Canal Zone, but the upperparts are grayish instead of blackish ; 

 the tail is relatively shorter — about equal to or shorter than the head 



1 Collection Amer. Mus. Nat. Hist. 



2 The species was originally described from " Panama," but the type in the 

 Berlin Museum remained unique for nearly 40 years. In view of the redis- 

 covery of the species in the suburbs of the City of Panama that place should be 

 definitely chosen as the type locality. 



