200 NORTH AMERICAN MUSTELID^. 



Description of the sJcull and teeth. {See Plates X, XI.) 



The cranium of no animal with which I am acquainted 

 varies more than that of the Skunk, and few exhibit such re- 

 markable differences, independently of age and sex. Some 

 specimens are more than a fourth larger than others, and 

 twice as heavy; and there is a corresponding range of varia- 

 tion in contour. Compared witli an ordinary ratio of osteo- 

 logical variability, the discrepancies are almost on a par with 

 those exhibited by the coloration of the animal when set over 

 against the more constant markings of most animals. In the 

 series of twenty or thirty skulls examined, I find that the 

 western ones, and especially those from the Pacific coast, 

 representing occidentalis of Baird, are, as a rule, larger and 

 heavier than others, more widened and flattened behind, with 

 stronger and more flaring sagittal and especially occipital 

 crests. Bat these extreaies shade insensibly into an ordinary 

 pattern, and I can draw no dividing line. Tables of meas- 

 urements would show these variations, though they would 

 scarcely render that realizing sense of the discrepancies that 

 is gained by laying the two extremes side by side. An average 

 cranium. No. 3816, from New York, is selected for description, 

 in the course of which the variations of the whole series will 

 be brought under review. 



The greatest zygomatic width is to the length as I to 1.55, 

 or slightly less than two-thirds such length. A similar pro- 

 portion is generally preserved. Viewed from above, the cra- 

 nium presents a short, tumid, rostral portion, high at the nose, 

 tapering on either side, but with a protuberance indicating the 

 course of the canine tooth in the bone, subtruncate in front, 

 with large subcircular nasal aperture, in this view much fore- 

 shortened. The rostrum is about a third of the whole length, 

 if measured from extreme front to anterior root of zygoma; 

 the zygoma, and then the rest of the skull, being respectively 

 another third. In other skulls, the rostrum is shorter than 

 this, and less vaulted. The general convexity of the rostrum 

 continues on to the forehead in the broad, smooth, interorbital 

 space. Supraorbital processes are very slight, being only indi- 

 cated in a little bulging at the front, where the anterior forks 

 of the sagittal crest come to the brim of the orbit. There is 

 thus scarcely any definition of the orbit from the general tem- 

 poral fossa. The point of greatest constriction of the skull is 



