258 Bulletin American Museum of Natural History. [Vol. XII, 



says : " C'est de 1'echymys dactylin, jeune encore, de M. Geof- 

 froy-Saint-Hilaire que j'ai tire ce systeme de dentition" (p. 186). 

 This species is also not congeneric with either of the two species 

 referred by F. Cuvier to the genus Echimys in 1809 and 1812, 

 and all three are now placed in separate genera. His ' echimys 

 dactylin ' became, in 1838, the type of Dactylomys I. Geoff roy, 

 and in 1843, the type of Lund's genus Echimys; his 'rat epi- 

 neux ' is the type of Loncheres Illiger, 1811, and congeneric with 

 the type of Nelomys Jourdan, 1838 ; and finally his * rat a queue 

 doree ' is congeneric with the type of Mesomys Wagner, 1845. 



Two years after Echimys was introduced into the literature of 

 zoology, namely, in 1811, Illiger proposed the genus Loncheres? 

 on the basis of a formal but rather meaningless diagnosis, and 

 the following : " Species : Loncheres paleacea (nova species e 

 ^Brasilia) et Hystrix chrysuros LinGmel" As the first species 

 here mentioned remained a nomen nudum till described by Lich- 

 tenstein in 1820, it cannot be taken as the type, under the A. O. 

 U. Canon XLII, which provides that the basis of a generic 

 or subgeneric name must be either " (r) a designated recogniza- 

 bly described species, or (2) a designated recognizable plate or 

 figure, or (3) a published diagnosis." As Loncheres paleacea com- 

 plies with none of these conditions, his " Hystrix chrysuros 

 LinGmel." becomes the type of Loncheres. This is in reality the 

 Myoxus chrysurus of Zimmermann, 9 variously accredited by later 

 writers to Boddaert, Schreber, Shaw, etc., which was based on 

 ' Le Lerot a queue doree ' of Allemand in Buffon's Hist. Nat., 

 " Suppl. IV, ed. d' Holl. p. 164, pi. 67," and is therefore a prior 

 name for Desmarest's Echimys cristatus Desmarest citing both 

 the "Lerot a queue doree, Buffon, Suppl., torn. 7, pi. 72," and 

 " Hystrix chrysuros Boddaert, Elench. mamm.," these references 



case, except for E. spinosus,' where it was doubtless accidentally omitted, as this species is 

 also claimed for E. Geoffroy by his son Isidore. These species are. as follows : 



1. " Echimys huppe (Echimys cristatus*) Geof. Lerot a queue doree Buff., . . . Hystrix 

 chrysuros Boddaert ..." (p. 55). 



2. Echimys dactylin, Echimys dactylinus, Geoffroy " (p. 57). 



3. Echimys epineux, Echimvs spinosus ; Rat epineux de Azara . . . ; Echimys roux, 

 Cuvier " (p. 57) 



Echimys a aiguillons, Echimys hispidus, Geoff." (p. 58). 

 Echimys didelphoide, Echimys didelphotdes, Geoff." (p. 58). 

 Echimys de Cayenne {Echimys cayennensis) Geoffr. ; d' abc 



" (*9). 



Echimys soyeux (Echimys setoi 



8 Syst. Mamm. et Avium, 1811, 90. 



9 Geograph. Geschichte, IV, 1780, 352. 



10 Nouv. Diet. d'Hist. Nat., ncuveJle ed., X, 1817, 55. 



abord Rat de la Guyane, du 

 meme 

 7. " Echimys soyeux (Echimys setosus) Geoffroy " (p. 59). 



