lOO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 69 



Other member of the group is known to range so far into Middle 

 America, but an aUied species, O. pirrensis, inhabits the mountains 

 of eastern Panama. The underparts in O. devius, unHke those of 

 O. pirrensis, are marked by white patches, as usual in the group. 

 The skull is similar, but more smoothly rounded, the zygomata less 

 widely spreading, the supraorbital and temporal ridges less distinct, 

 and the audital bullae decidedly larger than in O. pirrensis. 



The species is based on four specimens obtained by W. W. Brown, 

 Jr., from 4,000 to 5,000 feet altitude on the southern slope of the 

 Volcan de Chiriqui, and additional examples from the same locality' 

 acquired by the Field Museum of Natural History. 



Specimens examined: Boquete (type locality), 6.* 



ORYZOMYS PIRRENSIS Goldman 



Mount Pirre Rice Rat 



[Plate 24, figs. 5, 5a] 



Orysomys pirrensis Goldman, Smiths. Misc. Coll., Vol. 60, No. 22, pp. 5-6, 

 February 28, 1913. Type from near head of Rio Limon, Mount Pirre, 

 eastern Panama (altitude 4,500 feet). 



The Mount Pirre rice rat is a large member of the O. meridensis 

 group. It is similar in size to O. devius of western Panama, but 

 slightly darker in general color, and the underparts lack the pure 

 white patches usual in the group. The skull is more angular, with 

 zygomata more widely spreading, the supraorbital and temporal 

 ridges more distinct, and the audital bullae decidedly smaller. The 

 skull combines the large general size of that of O. devius with the 

 small audital bullae of O. meridensis and O. maculiventer; it differs 

 from both, however, in the development of the supraorbital and 

 temporal ridges. 



Like the allied species, O. devius, 0. meridensis and others of the 

 group, this large rice rat is an inhabitant of the mountains. It was 

 found only in the heavy forest at about 4.500 feet altitude where 

 precipitous slopes border the narrow canyon of the Rio Limon. The 

 animals live in holes under logs and rocks along steep overhanging 

 banks of the stream, where palms and tree ferns are conspicuous 

 vegetation. Several were caught in well-worn paths, bearing 

 many marks of small feet. 



Anthony (1916, p. 368) encountered this species at 5,200 feet on 

 the upper slope of Mount Tacarcuna where it did not appear to be 

 common. He notes the external resemblance to the much more 



^ Four in collection Mus. Comp. Zool. ; two in Field Mus. Nat. Hist. 



