124 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 69 



indicates probable intergradation. Specimens from extreme eastern 

 Panama show an approach to H. gymnurus in somewhat lighter 

 zygomata and slightly smaller audital bullae. Geographic variation 

 of relatively unimportant cranial details suggests the advisability of 

 regarding the Middle American forms as subspecies of Hoplomys 

 gymnurus!' 



Like the species of Proechimys this spiny rat seems to be terrestrial 

 in habits. Several examples were trapped under shelter of fallen 

 trees and rocks in the forest. One was caught in a steel trap set on a 

 narrow ledge under an overhanging river bank. Anthony (1916, 

 p. 370) lists specimens from Gatun and the old village of Tacarcuna 

 (2,650 feet). 



Specimens examined : Cana, 5 ; Gatun, 2 2 ; Rio Indio (type 

 locality) ; Tacarcuna, 6. 2 



Genus DIPLOMYS Thomas. Spiny Rats 

 The spiny rats of the genus Diplomys are distinguishable from 

 those of the other genera occurring in Panama by the short and 

 conspicuously tufted ears, the blackish hairs projecting about half 

 an inch beyond the margins. The face is marked by narrow vertical 

 stripes at the posterior base of the whiskers. The dorsal pelage is 

 bristly, but softer than in Hoplomys and Proechimys. The molari- 

 form teeth are more elongated antero-posteriorly, the crowns rec- 

 tangular instead of cylindrical in general outline, and each divided 

 until old age by three deep transverse furrows. The long tail is well 

 haired. The short, broad hind feet, and short, strongly curved claws 

 exhibit adaptation for an arboreal life. 



DIPLOMYS LABILIS (Bangs) 



Gliding Spiny Rat 



Loncheres labilis Bangs, Amer. Nat., Vol. 35, p. 638, August, 1901. Type 

 from San Miguel Island, Panama. 



Concerning this insular species I can add little to Mr. Bangs' full 

 original account. It was discovered by W. W. Brown, Jr., at the 



1 Pending further revision of the group the forms should therefore stand as 

 follows : 



Hoplomys gymnurus gymnurus Thomas, Cachavi, Ecuador. 



Hoplomys gymnurus gocthalsi Goldman, Rio Indio, near Gatun, Canal 



Zone. 

 Hoplomys gymnurus truei Allen, Lavala, Matagalpa, Nicaragua. 



2 Collection Amer. Mus. Nat. Hist. 



