3 



and curved as in Felts, being relatively longer than in Ursus. Phalanges 

 of the other series are quite short. The ungues are short and flattened, 

 their inferior surface is nearly plane, and the superior but little convex. 

 A shallow groove divides the upper face longitudinally to the ex- 

 tremity. The margin below is acute to a slightly contracted neck. 

 There is no indication of collar for reception of the horny sheath, except 

 perhaps a slight area of fracture on each side, and there is no projecting 

 tuberosity below for insertion of flexor tendon. The middle of the 

 proximal part of the unguis is a raised plane, and on each side of it, at 

 the neck, two arterial foramina enter. There is a small foramen in the 

 groove, and several smaller ones near the margin. These ungues re- 

 semble somewhat those of some tortoises. They were found with the 

 other phalanges, with which they agree in size and articulation, and no 

 doubt belong to the same animal. It is evident that they differ in 

 character from those of most existing Carnivora. The penultimate 

 phalanges agree with them in the depressed form of their proximal ar- 

 ticular faces, wanting entirely the triangular form so characteristic of 

 Carnivora, especially of the cats and dogs. The short flat shaft of the 

 same is almost equally peculiar. 



The cranium is fragmentary. The malar bone of the right side is 

 similar in position and form to that of the C unities, especially in the 

 presence of a weak angle only, to mark the posterior border of the orbit. 

 It has* a much less expanded union with the maxillary than in these 

 animals, and is proximally shallower, thicker and more prominant. Its 

 posterior portion is more plate-like. 



There are numerous teeth preserved, but separate from the skull and 

 mostly mandibular. The inferior canine is stout especially in the root, 

 which is a flat oval in section. The crown is but little curved, slightly 

 compressed, and without edge or groove. The premolars graduate into 

 the molars, so that the line of distinction is not easily drawn. The 

 first premolar has a single root ; the crown is slightly conic, with a 

 small tubercle at the base behind. This tubercle increases in size 011 the 

 premolars 2 and 3, and becomes on the true molars a longitudinal 

 cutting edge extending along the axis of the crown, not much elevated 

 above a wide base. It occupies half the length of the crown in the 

 larger molars, and is preceded by an elevated conic cusp. In front of 

 the base of this, a small conic tubercle projects forwards, which appeared 

 as a rudiment on the third premolar. The number of mandibular teeth 

 would appear to be, P.M. 3, M. 4. No portions certainly referable to 

 the superior molars were found. 



Conclusion. In summing up, it may be accepted as a result of the 

 above analysis that the genus Mesonyx represents a family of Carnivorci 

 digitigrada, distinct from any now living on the globe. The form of the 

 astragalus renders it probable that the inner toe is wanting or rudimental, 

 and that there were four digits on the hind foot. The foot was also short 



