﻿July, 1896.] 



HISTORY OF CLASSIFICATIONS. 



19 



already done nearly forty jenrs before, divides the subgenus Arvicola 

 ( = Microtus) into two groups, based on tlie structure of the middle 

 upper molar. To the species with this tooth formed of five prisms he 

 restricts the name Mynomes, while to those with the same tooth made 

 np of only four i)risms he applies the new name Tetramerodon. The 

 character in question is far too trivial to serve alone as the basis for a 

 subgenus. If, however, the advisability of subdividing the genus along 

 such narro w lines be admitted, the name Tetramerodon still becomes a 

 synonym of Microtus^ since 21. arvalis, the tyiDC of the latter, is itself 

 a species with the middle upper molar four parted. 



HISTORY OF FORMER CLASSIFICATIONS. 



The most important studies of the various groups of Microti)ue, but 

 more especially of the subgenera of Microtus, are those of De Selys 

 Longchamps (1836 to 1862), Blasius (1857), Baird (1857), Fatio (1867), 

 Coues (1874), Blanford (1881), and Lataste (1887). The names nsed by 

 these authors for the subdivisions of Microtus adopted in the present 

 classification are shown in the accompanying table: 



TaMe of Names used lij Authors for the Suhgenera of Microtus. 



Names used 

 ill the i)res- 

 ent paper. 



De Selys 

 Longchamps, 

 183G to 1862. 



Blasius, 

 1857. 



Eaird, 

 1857. 



Fatic, 

 1867. 



Coues, 

 1874. 



Elauford, 

 1881. 



Lataste, 

 1887. 



Arvicola 



Hemiotomys 

 ( Arvicola . . . 

 [A[ynomcf! .. 

 Microtus .... 



Paludicola 



Arvicola 



(part). 

 Arjricola .. 



Arvicola 

 (part). 





Praticola 

 (part). 



Praticola 

 (part). 



Sylvicola. . 



Terricola. . 







Arvicola. 



Microtus. 

 Pitymys. 



Lasiopodo- 

 mys. 



Microtus 



Pitymys 









Hemioto- 

 mys. 

 Fitymys . . 



Myonomes 

 IHtymys . . 



Xeo don, 

 (part). 





Pedomys. . 

















Paludicola 









Clnlotus 

































Alticola ... 

 Alticola 



part ?. 

 Xe 0 don 



(part). 



Syjjeracrius 













Eothenomys 























































De Selys Longchamps published two extended papers on the Euro- 

 pean Microtince, and later a note supplementary to the first of these. 

 The first paper appeared in 1836 under the title ^Essai Monographique 

 sur les Campagnols des environs de Liege.' In this the author showed 

 that hitherto the voles had been divided into two groups, according 

 to their habits, the aquatic species being separated from those that are 



