36 



NORTH AMERICAN FAUNA. 



[No. 36. 



Measurements. — Average of 5 adults from type locality: Total 

 length, 148 (142-151); tail vertebrae, 74 (71-78); hind foot, 19 

 (18.5-19.5). Skull: (See table, p. 81). 



Remarks. — This form is intermediate between megalotis and satu- 

 ratus, being slightly larger externally than megalotis, with skull about 

 the size of that of saturatus. One of the topotype series matches 

 megalotis very closely in color, but the others are much darker; all 

 have darker ears, tail, and underparts. 



The range of cinereus is apparently not extensive and is nearly 

 surrounded by that of saturatus, at least on the east, south, and west. 



Specimens examined. — Total number, 11, from the following locah- 

 ties in Mexico : 



Puebla: Chalchicomula, 5; Mount Orizaba, 1. 

 Tlaxcala: Apixaco, 2; Huamantla, 1. 

 Hidalgo: Real del Monte, 2. 



REITHRODONTOMYS MEGALOTIS SATURATUS Allen & Chapman. 



Dusky Harvest Mouse. 



(PI. I, fig. 8; PL IV, fig. 8.) 



Reithrodontomys saturatus Allen and Chapman, Bull. Am. Mus. Nat. Hist., IX, 1897, 

 p. 201. 



Type locality. — Las Vigas, Vera Cruz. 



Distribution. — From Jahsco (Ocotlan), Hidalgo, and Vera Cruz 

 south to Oaxaca; altitudinal range approximately from 6,000 to 

 10,000 feet. 



Characters. — Larger and darker (blacker and more intensely 

 ochraceous) than cinereus. 



Color. — Upperparts mixed black and ochraceous-buff, the black 

 predominating; sides with less black but without a distinct ochra- 

 ceous line; underparts grayish white, often strongly suffused with 

 ochraceous-buff; ears blackish, or fuscous with a large blackish patch 

 on the inner posterior margin; tail sharply bicolor, fuscous-black 

 above, whitish beneath; feet grajdsh white. 



Skull. — Similar in proportions to that of megalotis but decidedly 

 larger; zygomata parallel or sHghtly contracted anteriorly; closely 

 similar to those of tenuis and difficilis, but averaging larger, with 

 larger bullss and longer paJatal foramina. 



Measurements. — Average of 7 adults from type locality: Total 

 length, 162 (158-169); tail vertebrae, 87 (80-95); hind foot, 19 

 (18-19.5). Skull: (See table, p. 81). 



Remarks. — This is the largest and darkest form in the megalotis 

 group. It occupies the humid mountain slopes of southern Mexico, 

 intergrading with cinereus along the edge of the table-land and with 

 zacatecse in Michoacan. Its range meets that of R. fulvescens 



