21 



marg-in and thrcc timcs on thc inncr; inthe second molar thc enamcl 

 is indonted once on tlic outcr margin and twice on the inner ; and 

 in the lašt molar oncc on thc outer, and twice on tlie inncr. Fur 

 long and soft. Tail moderate, well clotlied with hair. Claws long, 

 but slightly curved and formed for burrowing. Fore-feet mode- 

 rately large. Thumb furnished with a distinct claw. Ears moderate, 

 well clothed with hairs. 



Species Mus (Scapteromi/s) tumidus. 



Subgenus 2. Oxymycterus*. 



Molars with the folds of enamel penetrating deeply into the body 

 of the tooth. Front molar of the lower jaw with three indentations on 

 the inner side and t\vo on the outer ; second molar with two on the 

 outer side and the šame number on the inner; the lašt molar \dt\\ 

 one indentation of the enamel on each side. Fur long and soft. 

 Claws long, but slightly curved, and formed for burrowing. A di- 

 stinct clavv on the thumb. Tail short, moderately furnished with 

 hair. Nose rauch elongated and pointed. 



Species Mus {Oxymycterus) nasutus. 



Subgenus 3. ABR0THEixt. 



Folds of enamel penetrating deeply into the sides of the molars. 



The front molar of the lower jaw has three folds of enamel on the 



inner side and tvvo on the outer ; the second molar lias two on the 



inncr side and one on the outer ; and the lašt molar has one on each 



side. Fur long and soft. Tail short, well furnished with hair. 



Thumb vnth. a short rounded nail. Ears well furnished with hair. 



Type Mus (Abrothrix) longipilis. 



Species 2 Mus {Ah.) ohscurus. 



3 olivaceus. 



4 micropus. 



ichvotis. 



6 ^xantliorliinus. 



7 canescens. 



8 arenicola. 



In general appearance these animals resemble Arvicolcc. 



Subgenus 4. CalomysJ. 

 Fur moderate, soft. Torsus almost entirely clothed beneath with 

 hair. Front molar with three indentations of enamel on the inner 

 side and two on the outer ; second molar with two on the inner 

 and two on the outer ; and the lašt molar with one on each side. 

 Type Mus (Calomi/s) bimaculatus. 

 Species 2 3Tus (Cal.) elegans. 



3 ■ gracilipes. 



Mus maurus and M. brevirostris I regard as belonging to the rc- 

 stricted genus Mus. In 3Ius Jlavescens the dentition differs slightly 

 from that of the ordinary mice. 



* Ojcį/mycferi(s, from 0|i/f, sharp, and IMyzr^j, nose. 

 + Abrotlirix, from'AĄoj, soft or dclicate, and 0cj|, hair. 

 X CaloinijK, from K«Xof, beautiful, and Mvr. 



