Vol. XXV, pp. 115-118 June 29, 1912 



PROCEEDINGS 



OF I'll I 



BIOLOGICAL SOCIETY OF WASHINGTON 



GENERAL NOTES. 



THE GENERIC NAMES CERGOMYS AND PROECHIMYS. 



Mr. E. A. Goldman lias recently* urged that the generic name Proechi- 

 mys for the common Spiny Rats should be dropped in favor of Cercomys, 

 given to his Cercomys cunicularius by F. Cuvier in L829. This opinion is 

 based on an identification — in which I entirely concur — of the skull and 

 teeth described and figured as those of Cercomys cunicularius, with those 

 of some member of what is usually called Proechimys. 



But there is one point which has aroused suspicion, namely that a 

 Proechimys young enough to have spineless pelage would have teeth in a 

 very different state of wear from those of the figured skull, which is not 

 only adult but old.t In Proechimys the pelage is always spinous before 

 adult age is reached. 



In searching for an animal with spineless fur to which the original 

 figure of <'< rcomys cunicularius could he assigned I have naturally thoughl 

 of Thrichomys apereoides Lund (Nelomys anlricola Lund, of Winge) 

 which occurs in Minas Geraes and agrees closely with the account and 

 figure of < 'ercomys. 



But the difficulty of the ProccJiimys-tike skull and teeth still remaining 

 I applied for help to the authorities in Paris, and Dr. Anthony has been 

 good enough to send me the only skull which is there assigned to Ccrco- 

 rnys cunicularius. To my great interest I find that it is a skull of 

 Thrichomys, slightly immature, hut is clearly not that figured by F. 

 Cuvier as the skull of Cercomys. 



The facts would therefore appear to be that the original Cercomys cuni- 

 cularius had a skull of Proechimys wrongly assigned to it when it was 

 first described in 1829, as may he gathered from the description of the 

 teeth, and that this same skull served for F. Cuvier's description and 

 figures in 1832. How and by whom the " Thrichomys" skull now before 

 mi', which was received as a "don du Musee de Geneve," became identi- 

 lied as a Cercomys is not known, but I have no doubt that it is rightly so 

 determined. 



With regard to nomenclature it is clear that the animal and not the 

 skull should be looked upon as the primary basis of the name Cercomys, 



• Proc. Biol. SOC. Wash., XXV, p. 94, 1912. 



f I venture to differ entirely from Mr. Goldman as to the age of this skull, which he 

 supposes to be young. The teeth present are worn down, and the last molar has been 

 lost. 



22— Proo. Biol. Soc. Wash., Vol. XXV, 1912, (115) 



