MURID^— ARVIC0LINJ3— AUVICOLA. 



153 



B. — CiiiLOTUS. Back upper molar with 1 external Iriaiiglu and a posterior 

 trefoil. Middle upper uiolar witli 1 internal triangle. Front lower 

 molar with 3 internal and 2 or 3 external triangles. Ear with a rim in 

 front of the meatus, owing to meeting there of the anterior and poste- 

 rior roots of the auricle. Sole 5-tuberculate (?). Fore claws not larger 

 than hinder ones. Tail about J the head and body. Pelage ordinary. 

 Of minimum size. 



C. — Pedomys. Back upper molar with 1 external triangle and a posterior 

 trefoil. Middle upper molar with 1 internal triangle. Front lower 

 molar with 2 internal and 1 external triangle. Ear unrimmed. Sole 

 5-tuberculate. Fore claws not larger than hinder ones. Tail about ^ 

 the head and body, or a little less. Pelage ordinary. Of medium size. 



D. — PiTYMYS. Back upper molar with 1 external triangle and a posterior 

 trefoil. Middle upper molar with 1 internal triangle. Front lower 

 molar with 2 internal and 1 external triangle. Ear unrimmed. Sole 

 5-tubcrculate. Fore claws larger than hind ones. Tail about J the 

 head and body, or less. Pelage dense, mole-like. Of small size. 



Subgenus MYONOMES, Rafinesque. 



< Arricola of American writers. 



=Arvicola A, Ilemiotomyi, Baiiu), M. N. A. 1857, 515 (type, Arvicola ri/urtv« Onn). Not of Selys-Lono- 



ciiAMi'8, wlioBe typo is the European Arvioola amphibim. 

 =.Mynonu»' RAFlNcsqcE, Am. Monthly Mag. ii, 1817, 45(tjpe, Munomea pratetuia Rakinesquii, wliioh 



is baaed on Wilson's Meadow-Mouse, Am. Oru. vl, pi. 50, f. 3, and is therefore = Arvioola 



peniujilvanioa Ord and auot.). 

 := Myonoma, Coues, Proc. Acad. Nat. Sui. Phila. 1874, 189. 



Chars. — ^'osterior superior molar witii an anterior loop, an internal 

 closed triangle, (wo external closed triangles, and a posterior crescent. Ante- 

 rior inferior molar with a posterior loop, an anterior trefoil, three lateral inter- 

 nal closed triangles, and two (or three t) lateral external closed triangles. 

 Middle superior molar with a supplementary postero-internal triangle. (Other 

 dental and cranial characters as in Arvicola at large.) Ears abouL 'equ % 

 the fur, rounded, hirsute, with well-developed valvular antitragus; no pc.ul- 

 iar construction of the concha. Tail exceeding the head in length (about 

 one-third as long as head and body), fairly hirsute and with terminal pencil, 



'The original orthography is MynoMtt. I do not know what, if any, meaning attaches totliis 

 word, bnt snpposo it to be compounded with //vf, so that it should bo spelled ifyonomeii, if not further 

 altered into Atyoiiomus. 



t When there . I'O three, tho third reeclts from change of tho outer leaflet of the anterior trefoil 

 into a triangle. 



\''4 



11: m 



