f 



ii r 



98 



MONOGliAPIIS OP NORTH AMERICAN RODENTIA. 



HESPEROMYS CALIFORNICUS, (Gambel) Baird. 

 Parasitic House. 



Miis ealifoniiciia, Gamiikl, Proc. Acml. Nut. Sci. Pliila. iv, 1848, 78 (Monterey). 

 IIcsperomnK eali/orniciiii, Uauid, M. N. A. 1857, 478 (Suutii Clora Comity, Cal.). 

 nmiierumiiH ( I'mpmrnm) californieus, C'0UE.s, Proe. Acad, Nat. Sci. PUilu. 1874, 180. 

 Ili-speromijK paravliom, Cooi'EU, MSS.— H.iini>, op, cit. 479 (in text). 



Diagnosis. — H. crassitie dimidlum muris decumanm suheequans, caudd lon- 

 gissimd suhntidd vix hicolore, pedibus uncialibus jilantis nudh, auriculis maxi- 

 7nis .warsisfdmh pilosis ; supra fuscus, lateribus sensim Jlavicantibus, infra 

 albidus. 



Nearly as large as a half-grown house-rat, with extremely long nearly 

 naked cars and tail, the latter scarcely bicolor ; feet an inch long, with naked 

 soles; dark grayish-brown above, becoming pale cinnamon-brown on the 

 sides, the under parts whitish. 



Habitat. — Southern and Lower California. 



Our few specimens, mostly the same as those described by Baird in 1857, 

 indicate a species perfectly distinct from leucopm. The animal looks, in fact, 

 much like a partly-grown Neotoma ; it is quite as large as some examples of 

 Oryznmyx pahistris, wliile its long and sparsely hairy tail, no less than its 

 size, gives it somewhat the aspect of a young Norway rat. No one of the 

 interminable variations of kucopus have so far shown us anything like this. 



The size and proportions of the species rre illustrated in the table given 

 below. It may be said to l)e four or five inches in length of trunk, with 

 the tail about the same — half an inch longer or as much shorter than the 

 head and body. The feet are an inch or a little more long, and share with 

 eremicus the peculiarity of naked soles, although the very extremity of thi; 

 heel is not |)erfectly denuded. The immense ears are a striking feature, 

 measuring three-fourths of an inch or more in height by about two-thirds of 

 an inch in widtli. They arc very closely pilous on i)oth sides, as will be seen 

 i)y close inspection, l)ut appear at first sight quite naked. The little hairs are 

 so short that they do not form any perceptible fringe. Tiie shape of the ear 

 is also remarkable ; instead of I)eing evenly rounded, it is like the two sides 

 of a rectangle with the upper corner rounded ofi". The tail is scant-haired, 

 showing the annuli plainly. 



The pelage is renuvrkable for its softness, fullness, and gloss, although it 

 is not long, measuring less than half an inch on tl\e back. It is very different 



