Miller — The Generic Name of the Hovse-Rats. 59 



1881. Epimys Trouessart, Bull. Soc. d'Etudes Sci. d' Angers?, X, p. 117 

 (type by subsequent designation Mufi rattus Linnseus). 

 External form, skull and teeth with no special modifications; molars 

 slightly graduated in size from first to third, the anterior tooth not tending 

 to assume the main function of the toothrow, the posterior tooth not tend- 

 ing to disappear, enamel folding of upper molars directly referable to a 

 simple 9-cusped pattern and its reductions, the outer margin of m' and m'^ 

 never with more than three cusps, the inner margin of same teeth never 

 with more than 2 cusps; m^ usiially with 5 roots, its first lamina not dis- 

 torted by the backward displacement of antero-internal tubercle ; upper 

 incisor moderately compressed, set at such an angle that its outer side is 

 worn smoothly away by action of lower tooth. 



Genus MUS Linn?eus. 



1758. Mas Linnteus, 8yst. Nat., I, 10th ed., p. 59 (musculus). Part. 



1814. Musculus Rafinesque, Precis des Decouv. Somiologiques, p. 13 (sub- 

 stitute for Mns). 



1837. Leggada Gray, Charlesworth's ^lag. Nat. Hist., I, p. 586. Novem- 

 ber, 1837 ( L. booduga Gray and Mus platythrix Bennett). 



1844. Drymomys Tschudi, Fauna Peruana, p. 178 (D. parvulus Tschudi 

 = Mus musculus Linnaeus. See Palmer, Index Gen. Mamm., p. 

 246). 



1876. Nannomys Peters, Monatsber. k. preuss. Akad. AVissensch. Berlin, 

 p. 480, August, 1876 {N. sctulosus Peters). 



1881. .Icromys Trouessart, Bull. Soc. d'Etudes Sci. d'Angers, X, p. 133 

 (synonym of Drymomys wrongly attributed to Wagner. See 

 Palmer, Index Gen. Mamm., p. 246). 



1896. Pseudoconomys Rhoads, Proc. Acad. Nat. Sci., Philadelphia, p. 

 531 , December 8, 1896. Mus ( Pseudaconnmys ) proconodon Rhoads. 



1900. Dryomys Philippi, An. Mus. Nac. de Chile, XIV, p. 20 (modifica- 

 tion of Drymomys Tschudi). 



• 



In general like Ejrimys but mechanical scheme of molars modified by 

 the elongation of crown of anterior tooth until it forms the main portion 

 of toothrow ; 7n} with three roots, its crown decidedly longer than those 

 of the two succeeding teeth combined, its first lamina much distorted by 

 displacement backward of inner tubercle into line with outer and middle 

 tubercles of second lamina; nv^ small and tending to disappear, in some 

 species without trace of first lamina; upper incisor much compressed, set 

 at such an angle that a subapical notch is normally cut in its outer side 

 by action of lower tooth. 



