Rattus as a Generic Name. 71 
The reference is as follows :— 
“2. Rattus spinosus, le rat épineux, d’Azara, vol. i. p. 73, 
longitudine 10 pollicum,... .” *. 
Even though it might be claimed that the combination 
was meant for a mere translation of Azara’s name, in form 
it is so correct and so similar to the “1. Hystrix macroura ” 
and ‘3. Hystriz chrysura,” that precede and follow it, both 
undeniably meant for generic and specific names, that I con- 
sider we are justified in regarding it in a similar light, and 
therefore as a valid founding of the generic name Rattus on 
the species spinosus. 
It is to be hoped that no earlier reference will be found, 
as should such occur it will in all probability prove to be 
based on Mus raitus, Linneus, and will therefore upset 
Epimys. But after considerable search I have failed to find 
anything earlier than Fischer’s fortunate reference to 
Azara’s animal. 
The application of Rattus among the Octodontidez has 
next to be considered, but attention must first be drawn to 
the much-discussed question of what species is the type of 
Echimys, F. Cuv., 1809. Of the two species originally 
included in it, the “ Lerot a queue dorée” and the “ Rat 
épineux de d’Azara” (i.e., Loncheres chrysurus and Echimys 
spinosus of recent zoologists), Dr. Allen, in 18997, fixed 
upon the latter as the type, on the ground of elimination, 
and this selection has been generally followed. But, un- 
fortunately, in a book to which Mr. Gerrit Miller has recently 
directed attention, Fleming’s ‘ Philosophy of Zoology, 1822 f, 
“ Hystrix chrysurus”’ is selected as the type of Echimys, and 
I fail to discover any means of upsetting this selection, 
which is exactly on all fours with that of Sciurus volans as 
the type of Pteromys, about which Mr. Miller wrote. 
If, then, as we are compelled to do, we accept Fleming’s 
selection, the name Echimys will become the correct term 
for the animals usually known as Loncheres, with Echimys 
chrysurus as the type, while the genus typified by Azara’s 
Espinoso will have to bear another title. 
For this latter the name Rattus, which has at least the 
merit of being short, will be available, antedating Goeldi’s 
Euryzygomatomys § by many years. Its two species are 
Rattus spinosus and R. laticeps. 
* G, Fischer, Zoogn. iii. p. 105 (1814), 
+ Bull. Am. Mus, xii. p. 262. 
t Vol. ii. p. 191. 
§ Bol. Mus. Paraense, iii. p, 179 (1901). 
