NEOTOMA.—ARVICOLA. 155 
2. Neotoma ferruginea. (Tab. XVI.) 
Neotoma ferruginea, Tomes, P.Z. 8. 1861, p. 282 (descr. orig.)’; Coues, Proc. Ac. Philad. 1874, 
p. 175°; Mon. N.-Am. Rodent. p. 22°. 
Hab. Mexico, Tehuantepec (Sumichrast, U.S. Nat. Mus.*); Guaremata, Duefias (Salvin, 
Mus. Brit.1). 
This very handsome Wood-Rat was first obtained by Mr. Salvin in Guatemala, and 
was fully described by Mr. Tomes!. Subsequently specimens were forwarded by Sumi- 
chrast from the southern parts of Mexico to the United-States Museum, as recorded by 
Dr. Coues?*, who remarks that the species furnishes an analogy to Hesperomys sumié- 
chrasti in its rufous coloration, long dark tail, and partially dusky feet. In the last two 
of these characters it agrees best with NV. fuscipes, Cooper, of which it may be regarded 
as a tropical representative; but its rich ruddy tints are peculiar to itself. Mr. Tomes 
believed that it also differed from the other species in its dentition; but neither 
Dr. Coues nor I have been able to confirm the observation, the characters described by 
Mr. Tomes evidently depending on the age of the specimen described. 
Of its habits, which probably agree with those of the last species, nothing has yet been 
recorded. Mr. Salvin tells me that it is a rare animal near Duefias, the only place where 
he found it. During his last visit, in 1873, he was only able to procure one specimen 
(that now figured); this was brought to him by Indians, who caught it on the banks 
of the River Guacalate. 
6. ARVICOLA. 
Arvicola, Lacépéde, Mém. de l’Inst. Nat. iii. p. 495 (1801)*. 
Hypudeus, Lliger, Prod. Syst. Mamm. p. 87 (1811, nec Keyserling et Blasius). 
The characters of this genus, the type of the subfamily Arvicoline, are so well known 
that it will be enough to refer to the rhomboidal cranium with divergent supraorbital 
ridges, rootless or semirooted molars composed of alternate prisms, small fore feet and 
claws, nearly naked hind feet, and short or moderate tail. The numerous species are 
mostly characteristic of the Palearctic and Nearctic faunas; but three have been 
received from Mexico, belonging to two different subgenera. ‘They may be recognized 
by the following diagnoses :— 
* It may appear to be inconsistent to retain some of the genera of Lacépéde’s ‘ Tableau’ while others are 
rejected as being imperfectly characterized (supra, pp. 3, 6, &c.). It appears to me, however, to be one of 
those doubtful cases in which discretion may fairly be used for the avoidance of unnecessary changes. Arvicola 
has ever since been in constant use, and has thus established its own legitimacy, while its rejection would 
cause almost as much confusion as the revival of Alouatta, Sapajou, and other justly-forgotten terms. 
' + Tn the British Museum there are two skins of Voles, obtained in Mexico by Mr. Charlesworth, which 
appear to belong to a fourth species; but unfortunately the skulls are wanting, and it is therefore impossible 
to identify them with any certainty. 
X 2 
