MURIDH—ARVICOLINS—EVOTOMYS. | 
Suspramity ARVICOLIN A. 
The characters of the group having been given on page 2 in a manner 
which suffices for present purposes, and some analysis of the genera being 
represented in the table on pages 4-6, we may immediately proceed to con- 
sider the various genera and species successively in detail. 
Genus EVOTOMYS, Coues. 
< Arvicola sp., AUCTORUM. 
< Myodes, Setys-LonGcuampes, Etudes de Microm. 1839, 87. 
= Hypudeus, KEYSERLING & Buiastus, Wirbelth. 1842 (type, Arvicola glareola), (not of Iliger, which in- 
cludes Mus lemmus, amphibius, and arvalis). 
= Hypudeus, Barry, M. N. A. 1857, 513, 515, 518 (type, Arvicola gapperi). 
== Evotomys, COUES, Proc. Acad. Nat. Sci. Phila. 1874, 186 (type, Mus rutilus, PALt.). 
’ appears to have been loosely, if not indiscrim- 
The name ‘ Hypudzeus’ 
inately, used by authors; and, before proceeding to its definition, we wish to 
explain the above synonymy, in vindicating the necessity for a new generic 
name. 
According to Agassiz, the name Arvicola, proposed by Lacépéde in 1803, 
applied to Mus amphibius and Mus arvalis, and therefore, of course, is out 
of the question for the present genus. 
According to Baird, the name ‘“‘ Myodes”, as used by Selys-Longchamps 
(1839), is the same as Hypudeus, Iliger, and therefore conflicts with Myodes, 
Pallas, of same date, applied to the Lemmings. 
“‘Hypudeeus”, Illiger, 1811, included Mus lemmus, amphibius, and arvalis, 
and is therefore inapplicable to the present genus. 
But Keyserling and Blasius, in 1842, in separating the old genus Arvicola 
into two sections, retained the name Arvicola for the largest and most compre- 
hensive of these, and applied Illiger’s term Hypudeus to the restricted group, 
of which Mus rutilus, rubidus, glareola, gapperi, &c., are typical. Baird, in 
1857, used Hypudeus precisely in the same sense that Keyserling and Blasius 
had attached to it. 
It is simply the old question: Shall a synonym of one genus become the 
tenable name of another genus? Here, Hypudeus, Uliger, a synonym of 
Arvicola, Lacépede, if not also a synonym of Myodes, Pallas, has been held by 
Keyserling and Blasius and by Baird as the distinctive name of a different 
genus. It is immaterial that these latter authors gave the term an entirely 
