28 



tcrnally in each. In the fiont molar of the lo\ver jaw the enamcl 

 enters the body of the tooth three times internally, and tvvice ex- 

 ternally. 



As the above-mentionedcharacters, in Mr. Waterhouse's opinion, 

 evidently indicated an aberrant form of the Muridse, he suggested 

 the propriety of constituting a subgenus under the name of Phyllo- 

 tis* for the reception of the species. 



They were characterized as foUows : — ■ 



Mus (Phyllotis) Darwinii. M. siiprd pilis cintiamomeis et ni- 

 grescentihus intermixtis ; unte oculos cincrasccntihtis ; genis, 

 luteribus corporis, et caudd prope hasin, falvo-ciniutmomeis; 

 parlihus inferiorihns pedibusąue alhis ; auribus permagnis, fere 

 nudis ; caudd caput corptisąue fere ceguante, suprd fusco-nigri- 

 cante, st/btus albd. 



unc. lin. 

 Longitudo ab apice rostri usque ad caudse basin 6 O 



caudce 4 9 



ab apice rostri ad marginėm oculi . O 8^ 



ab apice rostri ad basin auris .... 1 4^ 



tarsi digitorutnąue 1 1^ 



auris O 1 lį 



Auris latitudo O 1 1| 



Uuh. Coąuimbo. 



Tliis little animal is remarkable for its large leaf-like ears. 



Mus (Phyllotis) xanthopygus. M. suprd pallide brunneus 

 Jlavo-lavatus, ad latera Jlavcscens, subtits albus ; capite gris- 

 cescentc ; natibus Jlavis ; pedibus albis ; auribus niajusculis 

 pilis albis et Jlavis intermixtis obsitis ; caudd longitudincm cor- 

 poris fere cegiiantc, siq}rd nigricunte ; subtiis albd; vel/ere 

 longo et molli ; pilis corporis onmibus ad basin pluitibeis ; 

 mystacibus perlongis albescentibus, ad basin nigris. 



unc. lin. 

 Longitudo ab apice rostri ad caudse basin . . 5 3 



caudoi 3 10 



ab apice rostri ad marginėm oculi . O 6| 



ab apice rostri ad basin auris .... 1 3 



tarsi digitorumgue 1 1 



auris O 7 



Auris latitudo O 65 



Ilub. Santa Cruz. 



Mus (Phyllotis) griseo-flavus. M. suprd griseus jlavo-lava- 

 tus, ad latera Jlavus, subtus albus ; pedibus albis ; auribus 

 magnis et fere nudis ; caudd caput coipusfpie fere (Efjuante, 

 suprd fusco-nigricante, subtiis albd ; vellere longo, molli ; pilis 

 ad bases plumbeis. 



* PInjllolis, from <i>u'K>.ov, a leaf, aud Ov,, uto;, an ear. 



