﻿54 



NORTH AMERICAN 



FAUNA. 



[No. 12. 



otherwise widely different Xeofiher only. The tendency to bilateral 

 symmetry in the molars is shared by three other Asiatic subgenera, 

 Hi/peracrius, Eothenomijx^ and Anteliomy.s. 



AUicoJa, like Hyperacrius, is apparently a strictly boreal subgenus. 

 The following species are known : Microtus sfoliczl-amis Blanford, M. 

 roifUi (Gray), M. sfracheyi (Thomas), AF. Manfordi (Scully), and M. 

 albieauda (True). 



Subgenus HYPERACRIUSi Miller. 

 New subgeuus. Type Jrricola fertUis True. 



OeograpMc distrihuUon'of type species. — Central Kashmir, the Pir 

 Panjal Eange and the Kaj Nag Mountains." (True.) 



GeogrcipMc distribution of subgenus. — Mountains of central and south- 

 western Kashmir at elevations ranging mostly from 7,000 to 12,000 feet. 



Essentia I char a cters : 



Palate abnormal. 



m 8 without closed triangles. 



in 1 normally with 4 or 5 closed triangles and 7 salient angles, 

 m 3 normally with 1 or 2 closed triangles and 4 salient angles. 

 Mammre 4. 

 Plantar tubercles 5. 

 Sole liairy. 



Claws on bind feet longest. 

 Fur short and dense. 



Sl'ull. — The skull in the subgenus Ryperacrius (PI. I, fig. 11) differs 

 from that of AlticoJa in its longer rostrum, strong!}^ cuneate nasals, 

 narrower interorbital constriction, more abruptly flaring zygomata, and 



flatter brain case. The whole dorsal 

 outline of the skull is depressed so 

 that the zygomata are more nearly on 

 the level with the top of the skull 

 than in any other subgenus oi Micro- 

 tus. The audital bulla? (fig. 27) are 

 Fig. 27.— Auditai buUsB, (a) Microtus (AUi- proportionally Smaller than in Alti' 

 ml "('2.7'''" cola, true Microtus, or Fitymys. The 



brain case is much more depressed 

 than in Microtias proper (flatter even than in Fitymys), and viewed from 

 above it has a x)eculiar subcircular outline not known elsewhere in the 

 genus. Parietals i^roportionally smaller than in Microtus jn^oper; 

 squamosals and interparietal proportionally larger. The latter in old 

 individuals has much the same shape as in fully adult Arvicola^ 

 JS'eofiber, and Fiber. 



Bony palate. — The bony palate is exactly as in Alticola. 

 Enamel pattern in general, — The enamel pattern (fig. 28) has the gen- 

 eral appearance of that of Alticola. 



Front loiver molar. — The first mandibular tooth is indistinguishable 

 from the corresponding tooth in Alticola. 



^ Oi vitepdupioi, inhabitants of the heights. 



