NO. 1000. MAM}rA Lfi rnOM TTU: ALTAI MOUyTAIXF^—HOLLISTER. 517 



toward distinctly grooved incisors in several specimens. The name 

 eversmannii of Poliakoff has been misapplied by Biichner to an arvalis- 

 like Microtus from further south. This has caused considerable con- 

 fusion and Mr. Thomas has recently remarked that "judging from 

 Biichner's figure of the skull, M. eversmanni Poliakoff, would seem 

 to be either this [M. arvalis] or a related form, and not a Stenocra- 

 niusJ' ^ I believe that Professor Kastschenko, in his paper on the 

 forms of Stenocranius ^ fixes the true status of eversmannii, as a 

 mountain form of the wide ranging Stenocranius type. In this paper 

 Professor Kastschenko quite properly raises the question if the forms 

 of the subgenus Stenocranius linovni to him are not possibly all races 

 of one wide ranging species. These forms include M. gregalis (Pallas) 

 not Radde,^ not Poliakoff, of eastern Siberia; M. eversmannii (Polia- 

 koff'), in the mountains of south-central Siberia: M. slowzouni 

 (Poliakoff'), of the west Siberian steppes; and M. raddei (Poliakoff), 

 of the Transbaikal country. To these Kastschenko adds, in the same 

 paper, three new forms of M. sloivzowii; lutea from Tomsk, hrevicauda 

 from the Yakootsk District, and trldenticulata; the last described as 

 a "variety," not a race, with abnormal enamel pattern, and coming 

 from no special territory. 



The Microtus eversmanni of Trouessart,* is likewise not the M. 

 eversmannii of Poliakoff, but apparently that of Biichner, and there- 

 fore relates to some form of arvalis. 



MICROTUS (STENOCRANroS) TIANSCHANICUS Bttchner. 



1889. Microtus tianschanicus Buchner, Wiss. Res. Przewalski Central-Asien Reis. 

 Zool. theil, vol. 1, p. 107. 



Thirty-one specimens from the desert mountains near the Mon- 

 golian frontier in Tchegan-Burgazi Pass. The skins in this excellent 

 series are uniformly much lighter colored than the lot from the forested 

 mountains near Tapucha, which I have referred to M. eversmannii. 

 Aside from the color differences I can detect no characters to separate 

 them. The enormous difference in size of adult skulls of this species 

 is most exceptional but it seems to represent true mdividual varia- 

 tion. Examination of fresh specimens showed seven plantar tuber- 

 cles and, in old males, large side glands well forward of the hips. Of 

 two pregnant females examined July IS, one contained 7 embryos, 

 4 right, 3 left, 12 mm. in diameter; and one 8 large fetuses, 4 right 

 and 4 left. These mice seemed most abundant in the open alplands 

 at from 9,000 to 10,000 feet altitude. 



1 Ann. and Mag. Nat. Hist., ser. 8, vol. 9, p. 398, April, 1912. 

 = Ann. Mus. Zool. Acad. St.-P(§teisbourg, vol. e, 1901, pp. 16.5-206. 



s The Microtus gregalis of Radde and of Poliakoff (not of Pallas), from Transbaikalia, is renamed Microtus 

 poljakowi by Kastschenko in his paper in the Ann. Mus. Acad. St.-P6tersbourg. 

 « Cat. Mamm., vol. 1, p. 699. 



