Bailey North American Species of Sigmodon. 109 



Guerrero: Chilpancingo 5, Acapulco 1, near Ometepec 2, Tlaxtoquilla 1. 

 Oaxaca. Puerto Angel 5, Oaxaca 5, Tehuantepec 6, Tamazulapam 2 

 im., Huajuapam 3 im., Cuicatlan 1 im. (sp?). 

 Morelos: Yautepec 4 im., Quernevaca 2 im. 

 Michoacan: Querendaro 1 (very large). 



Sigmodon hispidus tonalensis subsp. nov. 



Type from Tonala, Chiapas, Mexico, No. 75,144, U. S. National Mus 

 eum, Biological Survey Collection. $ ad. Collected August 9, 1895 by 

 E. W. Nelson and E. A. Goldman. Original No. 8312. 



General characters. Similar to mascotensis but larger and slightly 

 browner; pelage very hispid. 



Color. Upperparts yellowish brown, more yellowish about nose; belly 

 creamy white; feet and tail dull brownish gray, tail not distinctly 

 bicolor. Young, duller and slightly darker colored. 



Skull. Long and narrow, heavily ridged in adults, interparietal 

 pointed at ends and wide in middle, pushing supraoccipital well back. 



Measurements. Type: total length 350; tail 166; hind foot 41. Skull 

 of type: basal length 34.5; nasals 15; zygomatic breadth 22; mastoid 

 breadth 14.5; alveolar length of upper molar series 6.8. 



Distribution. Western Chiapas and eastern Oaxaca. 



Specimens examined. Total number 5, from 3 localities: 



Chiapas: Tonala 1; Mountains near Tonala 1. 



Oaxaca: Santo Domingo 3 (not typical). 



Remarks. This is merely a large form of mascotensis, from which there 

 is no sharp geographic separation. Specimens from Chilpancingo, 

 Guerrero, could be referred to it as well as to mascotensis. 



Sigmodon hispidus major subsp. nov. 



Type from Sierra de Choix, 50 miles northeast of Choix, Sinaloa, 

 Mexico. No. 96,275, U. S. National Museum, Biological Survey Collec 

 tion. $ ad. Collected October 20, 1898 by E. W. Nelson and E. A. 

 Goldman. Original No. 13,154. 



General characters. Very large, almost equalling Mus norvegicus; feet 

 stout; tail with coarse annulations; pelage coarse and hispid. 



Color. Upperparts light brownish gray; nose yellowish; belly white 

 or yellowish white; feet light gray; tail blackish above, dark gray 

 below. 



SkuU. Massive and heavily ridged in adults; interparietal strap-shaped 

 with wide, rounded ends; nasals notched posteriorly; audital bullae 

 relatively as well as actually large and elongated. 



Measurements. Type: total length 365; tail 156; hind foot 40.5. Av 

 erage of 5 adults: 351; 160; 40. Skull of type: basal length 36; nasals 

 16; zygomatic breadth 23.5; mastoid breadth 16.4; alveolar length of 

 upper molar series 7.3. 



