CRANIAL CHARACTERS OF MEPHITIS PUTORIUS. 243 



well-defined ridges of bone divaricating from tbe sagittal crest. 

 This crest is a single and acute ridge in adult skulls; in young 

 ones, it is a tablet of bone, the sides of which separate almost 

 at once from the occipital protuberance. There is little post- 

 orbital constriction of the skulls; the least width there being 

 little, if any, less than the interorbital width. The lateral 

 divergence of the zygomata is much as in the last species; but 

 their upward convexity is usually greater, and the summit of the 

 arch is at its middle. Behind, the skull is notably widened 

 and flattened, almost as in Taxidea^ the intermastoid diameter 

 being relatively much greater than it is in either Conepatus or 

 Mephitis; in fact, it is not very much less than the interzygo- 

 matic width, in some cases at least. Nevertheless, the mastoid 

 processes are themselves less developed than in Mephitis proper, 

 extending little, if any, beyond the orifice of the meatus, instead 

 of flaring widely outward. The occipital crest is strongly de- 

 veloped, and its outline is characteristic in the great convexity 

 of contour on each side and deep median emargination ; in other 

 genera, the median emargination is always slight, sometimes 

 nil; and the lateral outline from the mastoid to the point where 

 the supraoccipital bones leave the general occipital crest is 

 about straight — if anything, concave. 



A notable peculiarity appears in the profile view of the skull. 

 The dorsal outline in Mephitis mephitlca is strongly convex, with 

 a high point about the middle, and this is carried to an extreme 

 in M. frontata ; in the present case, the same outline is nearly 

 straight from the ends of the nasals to near the occipital pro- 

 tuberance ; in fact, the skull it as flat on top as an Otter's, and 

 flatter than a Badger's. The zygomata are strongly arched 

 upward, with a regular curve throughout, instead of being 

 highest behind; the prominence of the bulla ossea on the floor 

 of the skull is sufficient to bring this part fairly into view from 

 the side, as is scarcely the case in M. mephitlca; this feature is 

 also due, in part, to an abbreviation of the mastoid process, 

 which is hardly at all produced downward. 



On the floor of the skull, the principal feature is the width 

 behind, which, being simply coordinate with the general lateral 

 dilatation already noticed, requires no further comment. The 

 parocciiHtals are very small — in fact, mere nibs of bone, hardly 

 able to bear the term " process". There are also strong points 

 in connection with the bullae auditoriae and periotic region gen- 

 erally. The bullae are not only more swollen at the usual point 



