76 NORTH AMERICAN MUSTELID.E. 



convex, slopiug more rapidly dowu bebiud, with a frontal concavity and 

 oblique nasal oritice. The roof of the brain-box is convex in every direction : 

 a temporal "fossa" being only indicated by the ridges (sagittal and lamb- 

 doidal), which indicate the extent of the temporal mnscle. The sagittal crest 

 divaricates anteriorly to rnn out to each supraorbital process ; in old ani- 

 mals, it is a thin high ridge ; in the young, a tablet of greater or less width. 

 The occipital crest rises and flares with age, but is always a thin edge. The 

 occipital depression below this is well marked; the condyles are notably 

 projecting, and connected by a sharp ridge below the foramen magnum. 

 The mastoids are not conspicuous. The bulhe are large, elongate, oblique, 

 convex forward ; a slight constriction across them, and some outward pro- 

 longation, develops a tubular meatus. Excepting the bullie, the general 

 floor of the skull is quite flat. The palate is completely ossified some dis- 

 tance back of the molars, and nearly plane. A broad, deep emargination 

 lies between the pterygoids ; these are simply laminar, vertical, and terminate 

 in a well marked hamular process. The palatal plates of the intermaxil- 

 laries, when not fused, are seen to be of very slight extent ; the small incisive 

 foramina do not reach as far back as the hinder border of the canines. The 

 orbits are pretty well defined by the curve of the zygoma and presence 

 of supraorbital processes, but are not otherwise distinguished from the 

 general temporal cavity. The anteorbital foramen is large, high up over the 

 fore edge of the last premolar. The nasal orifice has a well-iiiarked and little 

 irregular bony parietes. 



The jaw has a lightly and somewhat irregularly convex inferior profile. The 

 coronoid plate is large, erect, its apex reaching or slightly overlapping the 

 zygomatic arch. The angle of the jaw is a slight sharp process. The con- 

 dyle is low, about on the level of the teeth, broad from side to side, but very 

 narrow in the opposite direction. Its reception in the glenoid fossa is close, 

 but the articulation does not lock as in JJeles or Taxidea. 



The single upper molar is completely tubercular, low, flat, with irregular 

 minor elevations and depressions, much broader transversely than length- 

 wise, subquadrate in general contour, partly divided by a slight median 

 constriction (both vertical and horizontal), with an inner and outer moiety, 

 whereof the former more or less considerably exceeds the outer in length. 

 The inner border of this inner moiety is always strongly convex, with a 

 raised brim. In typical M. martcs, the inner moiety is twice (to speak 

 roundly) as large as the outer. In M. americana, much as in foina, the 

 disproportion is obviously less. The outer border of the outer moiety in 

 vtartes is simply convex; in the other forois just mentioned it is more or 

 lessemarginate. The inner moiety shows one tubercle within the brim ; the 

 outer has two such. 



The next tooth — last premolar — is the largest of all, and sectorial in char- 

 acter, but with a promiueut fang projecting inward from the anterior end. 

 In profile, it shows a large, pointed, central cusp, flanked before and behind 

 with a small one. There is quite an excavation between the large central 

 and small posterior cusps. The next two molars, of nearly equal size, are 

 much smaller than the last, but repeat its characters in diminishing degree, 

 minus the antero-internal faug. The remaining anterior premolar is very 

 small. It is a simple conical cusp, with a slight heel behind, but none be- 

 fore; it occasionally aborts. The large canines are not peculiar. The six 



