but there has also been a notable increase in the number 

 of genera and subgenera, and changes in the status of 

 several of those previously recognized, as well as in the 

 nomenclature of some of the older species. The old genus 

 HesperomyshdiS not only been dismembered by the raising of 

 the United States subgenera Vesperimus (Coues =Sitomys 

 Fitzinger, of earlier date), Onycliomys and Oryzomys, and 

 the Mexican and Central American Tylomys, Rhipodomys, 

 and Abrothrix to full generic rank, but a new subgenus 

 Baiomys x has been proposed, and the name Hesperomys 

 discarded as untenable, at least so far as the North American 

 Muridae are concerned. 2 The genus PJienacoviys was 

 described by Dr. Merriam 3 in 1889, with 4 species, to which 

 others have since been added. 4 



This is a boreal type which barely reaches the mountain- 

 ous portions of the United States, north of which it ranges 

 across the continent from ocean to ocean ; yet prior to 

 1889 not a specimen appears to have been seen, or at least 

 critically examined, by any naturalist. 



The Red-backed Meadow Mice, forming the genus 

 Evotomys, known from I species and 1 additional subspecies 

 in 1884, now numbers 9 species with 3 additional subspecies, 



1 True, Proc. U. S. Nat. Mus. XVT., p. 758, Feb., 1S94. Type, Hesperomys 

 taylori Thomas. 



2 Cf. Allen, Bull. Am. Mus. Nat. Hist., III., pp. 291-294, June, 1S91. 



3 N. Am. Fauna, No. 2, pp. 27-35, Oct., 18S9. 



4 Phenacomys intermedins Merriam, N. Am. Fauna, No. 2, p. 32, Oct., 1889. 

 Kamloops, British Columbia. 

 ' Phenacomys celatus Merriam, ibid., p. 33. Godbout, P. Q., Canada. 



Phenacomys Iatimanus Merriam, ibid., p. 34. Fort Chimo, Ungava, 

 Labrador. 



Phenacomys ungava Merriam, ibid., p. 35, Fort Chimo, Ungava, Labrador, 



Phenacomys longicaudus True, Proc. U> S. Nat. Mus., XIII. , p. 303, Nov., 

 1890. Coos Co., Oregon. 



Phenacomys orophilus Merriam, N. Am. Fauna, No. 5, p. 65, July, 1S91. 

 Idaho. 



