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Vol. XXIX, pp. 205-208 September 22, 1916 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



r 



GENERAL NOTES. 



THE GENOTYPES OF ECHIMYS AND LONCHERES. 



In a recent article* Mr. Oldfield Thomas has assumed that Rattus G. 

 Fischer (1814) is available as the generic name of 'le rat epineux' of 

 Azara, being unaware that Hollistert had already traced the use of the 

 name Rattus in a generic sense back to 1803, when it was used by G. 

 Fischer himself in a way to make Mus decumanus the genotype of Rattus, 

 which thus must displace Epimys Trouessart (1881), as maintained by 

 HoUister. But Thomas's new "application of Rattus among the Octo- 

 dontidse " leads him "to the much-discussed question of what species is 

 the type of Echimys, F. Cuv. , 1809." He refers to my fixation of the 

 type upon Echimys spinosus, "on the ground of elimination," in 1899,$ 

 but considers my fixation of the type overthrown by the fact that Fleming 

 in 1822§ selected ' Hystrixchrysurus' as the type of Echimys. "If then," 

 he continues, "as we are compelled to do, we accept Fleming's selections 

 the name Echimys will become the correct term for the animals known 

 as Loncheres, with Echimys chrysurus as the type, while the genus typified 

 by Azara's Espinoso will have to bear another title." I fail to see that 

 this necessarily follows, for the following reasons : 



Echimys F. Cuvier, 1809, contained only two species, ' le Lerot k queue 

 dor6e' of Allemand {Myoxus chrysurus Zimmermann, 1780), and ' le rat 

 epineux ' of Azara. Therefore one of these two, as they are not congeneric, 

 must be taken as the type of Echimys. One of these species became, in 

 1811, the type of Loncheres Illiger. This left in Echimys only one of the 

 two original species, namely, 'le rat epineux' (Echimys spinosus Des- 

 marest, 1817), which automatically, under modern codes of nomencla- 

 ture, || became irrevocably its type. (I said, writing seventeen years ago, 

 before the expression became taboo, " by the process of elimination.") 

 Loncheres Illiger also contained nominally two species, (1) L. paleacea, a 

 species not described till nine years later, and therefore a nomen nudum , 



• On Rattus as a Generic Name, with a Note on the Nomenclature of Echimys and 

 Loncheres. Ann. and Mag. Nat. Hist. (8) . XVIII. pp. 70-72, July, 1916. 



tThe Generic Names Epimys and Rattus, Proc. Biol. Soc. Washington, XXIX, p. 

 126, June 6, 1916. It is evident that Thomas could not have seen Hollister's paper, which 

 preceded his in publication by only about three weeks. 



tThe Generic Names Echimys and Loncheres. Bull. Amer. Mus. Nat. Hist.. XII, 

 pp. 257-264, Dec. 26, 1899. 



§ Philosophy of Zoology, II, 1822, p. 191. 



II See Opinion 6, International Zoological Commission. 



35— Proc. Biol. Soc. Wash., Vol. XXIX, 1916. (205) 



