54 CARNIVORA order hi 



3 13 1 



Frotopsalis Go-pe) (Fig. 79, B). Dentition ' ' ' ' • F \ lost; 3P very small 



Jj, 1 -O, Z, 



or wanting, ilf j with faint talonid and small metaconid. M^ resembles M-^ 



of the Felidae, while 71/^ may be compared to P'* of the latter. Muzzle 



truncated, mandible massive, limbs short and stout, toes spreading. Possibly 



semi-aquatic in habits. F. ulta Leidy. Wasatch and Bridger beds. 



Falaeonidis Blv. Dentition ''' -'. F^ and F^ with lower inner tubercles. 



M^ with well-defined paracone and metacone, large protocone and intercalary 

 tubercles. Inferior molars with strong paraconid and metaconid, concave 

 talonid. i)/-^ larger than ilig- Wasatch beds of North America and Lower 

 Eocene of Soissons, France. 



Amblodonus Cope. I- M. M.-, of carnassial type lacking metaconid and 

 heel, but smaller than M^ Wasatch beds. North America. 



Family 4. Hyaenodontidae Cope. 



3-2 



— - — M. M |- developed as carnassial teeth. F'^ and anterior molars 



functioning as subordinate shearing teeth. Cranium usually long, less often short arid 

 stout, with concave forehead. Extremities mesaxonic, adapted for running, fibula 

 articulating with calcaneum. Claws cleft at the tips. Auditory bulla very rarely 

 completely ossified. 



The Hyaenodontidae embrace forms ranging in size from a fox to a wolf, 

 some species attaining the dimensions of a tiger. There is a tendency towards 

 the anchylosis of the scaphoid and lunar (Fig. 77, B); the humerus acquiring 

 a stout deep trochlea and supratrochlear foramen, while pollex and 

 hallux may undergo considerable reduction. The cranium is generally 

 narrow and elongate, but may, as in . Pterodon, and in many species of 

 Hyaenodon, be short and broad. Of the upper teeth, ]\'P may disappear, ]\P forms 

 a shear with M.^, M^ and F^ function similarly with ilf ^ and i/o respectively. 

 As a result of the cutting plates so formed, only the paracone and metastyle 

 of the upper molars remain, and the paraconid and protoconid of the lower. 



Subfamily 1. Provi%'ERRINae. 



^ M. Upper molars tritubercular. M^ transversely placed, lower M tuberculo- 

 sectorial, always with a metaconid. Teeth with moderate shearing surface. Body 

 slender. Extremities tvith five digits, which are of nearly uniform length. Claws 

 compressed. 



The Proviverrinae were approximately the size of a fox, possessing a civet- 

 like aspect. The ancestors of most true carnivores are to be sought in 

 this neighbourhood. 



Sinopa Leidy (Stypolophus, Frototomus Cope). F long and remaining 

 isolated. Outer tubercles of superior molars distinct, talonid large and 

 basin-shaped. The extremities, apart from the non-fusion of scaphoid and 

 lunar, resemble those of the Viverridae, but the symmetry of the foot is 

 mesaxonic, and the claws are cleft. Wasatch beds. S. Mans Cope. Bridger 

 beds. S. rapax Leidy ; -S*. grangeri Matthew. Possibly represented also in the 

 basal Eocene of Belgium (Orsmael). 



