258 Bulletin American Museum of Natural History. [Vol. XXII, 



39. Conepatus sonoriensis Merriam. 



Thirty-six specimens: Arroyo de Plantanar, 3 specimens, Feb. 

 16, 17; Estancia, 4 specimens, Jan. 22, 27, March 13; Garabatos, 

 6 specimens, March 20-26; La Laja, 13 specimens, May 17-24; Las 

 Canoas, 9 specimens, Aug. 5, 12; Los Masos, i specimen. 



Very -uniform in coloration. The black at the base of the under 

 surface of the tail, however, is somewhat variable, being usually 

 limited to the basal inch or less (occasionally wanting), but sometimes 

 extending to two inches or slightly more than two inches. Besides 

 this, the sides and lower surface of the basal fourth to basal third of 

 the tail have often a slight mixture of black hairs mingled with the 

 white, sometimes amounting to a conspicuous blackish grizzle. 



Collector's measurements: 16 males, total length, 616.3 (566-699 

 only 2 above 631); head and body, 372.5 (337-445 only 2 above 

 381); tail vertebrae, 238.8 (216-267 only i above 257); hind foot 

 without claws, 66 (60-70), with claws about 5-7 mm. more; ear from 

 notch, 26 (25-28): 10 females, total length, 594 (551-635 only 2 

 above 616); head and body, 349 (330-381); tail vertebras, 245 (221- 

 263); hind foot without claws, 63 (57-66); ear. from notch, 25 



(23-28). 



Skulls: 8 skulls of males (fully adult to old) measure, total length, 

 80.6 (77.5-85); basal length, 66 (62-68.5); zygomatic breadth, 50 

 (45-56); mastoid breadth, 42.3 (41-45.5): an old female skull, 76, 

 62, 47-5, 38. 



Compared with the Sinaloa series (ante a, p. 225), the only dif- 

 ference in coloration is evidently mainly seasonal; the Sinaloa (Escui- 

 napa) specimens were nearly all taken in February, just before the 

 spring moult, and were thus in worn, faded pelage, and, excepting 

 some of the younger specimens, were brownish black instead of deep 

 black; the Jalisco series was all taken later in the season, mostly in 

 May and August, when the pelage was unworn and fresh, with the 

 black parts of the animal deep, intense black. 



There is also no appreciable difference .between the skulls of the 

 two series, either in size or details of structure, a series of comparable 

 male skulls varying in their principal measurements, in the average, 

 less than a millimeter in length and about 2 mm. in breadth, the 

 Jalisco specimens averaging slightly broader in both mastoid and 

 zygomatic dimensions. There is, however, a notable discrepancy in 

 external measurements, the Sinaloa series averaging about 100 mm. 

 longer in total length, and about 25 mm. in length of tail vertebrae, 



