ARVICOLA. 157 
Oldfield Thomas, however, has called my attention to two spirit-specimens in the British 
Museum, received from Tehuantepec through M. Boucard, and to a skin, also obtained 
in Mexico by M. Rébouch, which agree in all essentials. On examination, I find that their 
dentition is identical with that of A. riparius; but, as Dr. Coues has remarked, the teeth 
of all the species of the subgenus Myonomes agree in pattern. One of these examples 
has the tail even shorter than the measurement given by M.de Saussure ; in another it 
is longer, although still falling considerably short of Dr. Coues’s average for A. riparius ; 
while that of the third has unfortunately been lost. It is to be noted, however, that one 
of the most southern specimens examined by the latter zoologist, from Louisiana*, had 
an even shorter tail than the Tehuantepec example in the British Museum; and I have 
little doubt that when a sufficient series of Mexican Voles is available for study it will 
be found that A. mexicanus gradually passes into the longer-tailed and larger-footed 
northern form. 
The subgenus J/yonomes, revived by Dr. Coues from Rafinesquef, is identical with 
the Hemiotomys of Professor Baird, but not with M. de Selys-Longchamps’s group of 
that name§, which is founded on the European Water-Vole, Arvicola amphibius, Linn. 
Myonomes is certainly very closely allied to the Arvicola proper of Blasius, if it does 
not prove to be identical with that subgenus. 
2. Arvicola pinetorum. 
Psammomys pinetorum, Le Conte, Ann. Lye. New York, iii. p. 138, t. ii. (1829, descr. orig.)'. 
Arvicola (Pitymys) pinetorum, Baird, Mamm. N. Am. p. 544°; Coues, Proc. Ac. Philad. 1874, 
p. 191°; Mon. N.-Am. Rodent. p. 219°. 
Hab. Norn America, from Massachusetts southward 4.—Mexico ( Verreaur, Mus. Brit.), 
Parada, Rancheria del Jacale (Sallé, Mus. Brit.). 
- The most southern localities which Dr. Coues gives for the Pine-Vole are the States 
of Mississippi and Louisiana; but it appears to extend far into Mexico, from which 
country there are three skins in the British Museum which I am quite unable to dis- 
tinguish from the more northern animal, One of these specimens is labelled by Sallé 
as having been obtained at the Rancheria del J acale, at an elevation of 12,000 feet and 
near the eternal snow. 
3. Arvicola quasiater. 
Arvicola (Pitymys) pinetorum, var. quasiater, Coues, Proc. Ac. Philad. 1874, p. 191 (descr. 
orig.) *. 
Arvicola (Pitymys) quasiater, Coues, Mon. N.-Amer. Rodent. p. 226’. 
* Mon. N.-Am. Rodent. p. 184. + Cf. supra, p. 156. 
+ Mamm. N. Am. p. 515 (1857). § Rev. Zoolog. x. p. 310 (1847). 
