1899-] Allen, The Generic Names Echimys and Loncheres. 261 



the old genus Echimys of F. Cuvier and subsequent French au- 

 thors into three, namely, Echimys, Nelomys, and Dactylomys, the 

 latter being new. These innovations all date from 1838, being 

 covered by the abstract, although the paper in full was not pub- 

 lished till 1840. The three genera are founded mainly on differ- 

 ences in the conformation of the teeth, and on the form and 

 relative size of the feet ; the size and shape of the ear, and the 

 condition of the tail as to whether naked or clothed, being con- 

 sidered as not characters of generic importance. His genera 

 (1838) are (i) Echimys, with six species, including one new, and 

 one doubtful ; (2) Nelomys, with also six species, including one 

 new ; (3) Dactylomys, with one species. These three genera and 

 thirteen species, in the order of the memoir proper (1840) are as 

 follows 1 : 



I. DACTYLOMYS. 



1. D. typus = E. dactylinus Desm. 



II. NELOMYS. 



2. N. cri status (Desm.). 



3. N. paleaceus (Licht.). 



4. N. blainmllii Jourdan. 



5. N, semivillosus, sp. nov. 



6. N. didelphoides (Desm.). 



7. N. armatus I. Geoff. = Mus. hispi- 



dus Licht., not E. hispidus 

 Desm. 



III. ECHIMYS. 



8. E. setosiis Desm. 



9. E. cayennensis Desm. 



10. E. myosunts( Licht.) = Loncheres 

 longicaudatns Rengg. 



11. E. albispinus, sp. nov. 



12. E. spinosus Desm. 



13. E. hispidus Desm. 



Of the generic distinctness of Dactylomys there is of course no 

 question, and it can be set aside without further consideration as 

 being in no way involved with Echimys, Loncheres, or Nelomys. 

 Respecting Nelomys, he says : " J'ai trouve que V Echimys crista- 

 tus et le Nelomys blainvillii sont bien, comme 1'a avance M. Jour- 

 dan et comme 1'a admis M. Frederic Cuvier, deux especes 

 parfaitement congeneres." Consequently Nelomys (type N. 

 blainvillii) Jourdan is a pure synonym of Loncheres, which, on 

 the principle of elimination, has E. cristatus as its type. 



Respecting Echimys, I. Geoffrey says : " Ce genre, appele 

 Loncheres par Illiger, comprenait, avec les especes qui s'y trou- 

 vent conservees, celles qui sont presentement separees sous les 



1 The authority for Echimys^ and for all the species here assigned to Desmarest, is given as 

 " Geoff . St.-Hilaire " (= E. Geoff. St.-Hilaire), from their having been first named by his 

 father, although admittedly not published by him, but by Desmarest. 



