NO. 5 MAMMALS OF PANAMA GOLDMAN 1 23 



Bangs in describing this form and recording 51 specimens collected 

 by Mr. Brown remarks : 



" The San Miguel spiny rat is a slightly differentiated' island form 

 of the centralis [P. semispinosns] series. It was very common in 

 the island, and Mr. Brown easily took as many specimens as he 

 wanted. It is known to the islanders as raton mockungay. They, 

 however, believe the tailless individuals are a different animal. 

 About one-third of the specimens taken were tailless. The animal 

 was generally distributed throughout the island, and was often found 

 living in the huts and sheds of the negroes, like the common rat." 



Specimens examined : San Miguel Island, 43. 1 



Genus HOPLOMYS Allen. Spiny Rats 

 The genus Hoplomys may easily be recognized among the Octo- 

 dont genera of Panama by the remarkably stout spiny armature. 

 The blackish spines, nearly two millimeters in greatest breadth, 

 project conspicuously beyond the softer element of the pelage over 

 the back. The ears are nearly naked, instead of conspicuously tufted 

 as in Diplomys. The supraorbital vibrissa? are very long, reaching 

 posteriorly to the shoulders. The transverse grooves in the molari- 

 form teeth are shallow and their partial obliteration and the forma- 

 tion of enamel islands through wear beginning at an early age results 

 in a complex crown pattern much as in Proechimys. Generic dis- 

 tinction rests on the more intricate enamel folds, especially of the 

 last upper molar which has four principal grooves instead of three 

 as in the latter genus. The claws are long, nearly straight, and indi- 

 cate terrestrial habits. The long, nearly naked tail breaks readily 

 close to the body, the stump heals over, and a tailless animal some- 

 times believed to be of a distinct species results. 



HOPLOMYS GYMNURUS GOETHALSI Goldman 



Goethals Spiny Rat 



[Plate 26, figs. 2, 20] 



Hoplomys goethalsi Goldman, Smiths. Misc. Coll., Vol. 56, No. 36, p. 10, 

 February 19, 1912. Type from Rio Indio, near Gatun, Canal Zone, 

 Panama. 



The Isthmian representative of the genus externally resembles 

 Hoplomys gymnurus Thomas and Hoplomys truei Allen. The heavy 

 zygomata and other cranial characters are distinctive, but additional 

 material obtained since the publication of the original description 



1 Forty-two in collection Mus. Comp. Zool. 



