678 CLASS XVII. 



Neotoma Say and Oed. Incisors smooth, yellow in front; 



3 — 3 



molars n — rr , complex. Ears exsert, somewhat large, oval. Feet 

 o — o 



pentadactylous. Tail long, clothed with long hair. 



Sp. Neotoma Drummondil, Eichardson Fauna hor. Amer., Mamm. p. 137, 

 PI. TII. (VIII.), North America ; the habitus resembles that of Myoxus or 

 Chinchilla, more than that of Mus; — Neotoma jloridanum Sat. 



Sigmodon Say and Ord. 



Sp. Sigmodon hispidum Say and Ord, Arvicola hortensis Harlan Faun. Am. 

 (a species unknown to me). 



Hy^udceus Illig. (in part), Arvicola Lac, Cuv. Incisor teeth 

 /3 _ 3\ 

 smooth, molars [^ — o) complex, with folds of. enamel describing 



triangles, alternating in a double row on the surface of the crown. 

 Ears moderate or small, rounded, almost concealed under the hair 

 of head. Fore feet tetradactylous with hallucar wart, hinder pen- 

 tadactylous ; claws small ; soles naked. Tail moderate or some- 



, , , • T. r r^ • 1-1 1-1 2-2 



what short, hany. Dent. lorm. Uwen, 1. t— 7 , P- -. _ ^ , ni. ^—^ 



16. 



Sp. Hypudwus amphihius Illig., Mus terrestris et amphibius L., Buff. vil. 

 PI. 43, ScHREB. Sdugth. Tab. 186, Cuv. E. Ani., ed. ill., Mamm. PI. 58, 

 fig. 3; the water-rat, le rat d'eau; 7" long besides the tail, which is 3" or 

 more long ; brownish, grey below ; as varieties of this species are regarded 

 Mus terrestris (L?) Hermann, which is smaller, Arvicola destructor Savi 

 dL,TiA. Arvicola monticola De Selys-Longch. — Hypudceus arvalls, Musarvalis 

 Pall., Buff. vii. PI. 47, Schreb. Sdugth. Tab. 191; the field- campagnol, 

 meadow-mouse, of the size of a mouse ; tail only one-third the length of 

 the body ; colour yellowish-grey, below whitish-grey. This species is, like 

 Mus sylvaticus, very numerous in some years, so as almost to destroy the 

 harvest; such was the case in 18 18 and 18 ig iu Holland and elsewhere ; 

 see C. Nicati Commentatio de Mure domeslico, sylvatico atque arvali iu 

 Ayinal. Acad. Rheno-Traject. 1823, 



Hypudwus ceconomus Illig., Mus osconomus Pall., Schreb. Sdugth. 

 Tab. 190; GuERiN Iconogr., Mammif. PI. 26, fig. 3; this species, at home 

 in Siberia, lays up a great quantity of roots, &o. against winter, and 

 travels away at indeterminate times in numerous troops. 



Compare on this genus De Selys-Longchamps Etudes de Micromam- 

 mologie, 1839, pp. 81 — 132 ; the same in Eevue zoolog. 1847, pp. 305 — 312, 

 and Gkebe Revue et Magas. de Zool. 1852, pp. 257 — 270, 305 — 312, 

 449—460, PI. II, 13, 14, 18, 19. 



