GEOLOGICAL SURVEY OF THE TERRITORIES. ' 557 



Among Carnivora, the feet are like both clogs and bears. The very 

 prominent i)oatglenoid ridge, and the narrow tympanic chamber* are 

 decided points of resemblance to the bears, but the cavum tympani is 

 even less expanded than in those animals. The characters of dentition 

 are more like those of the Hywnodontidw and Mcsonyx than any other 

 group, and even the remarkable incisor-like inferior canines are approxi- 

 mated by the anteriorly directed canines of Hyivnodon leptorhyiichus, 

 Laiz. et Par. 



As a summary, it may then be concluded that the genus Synoplothe- 

 rium is a Carnivore, presenting a number of points of resemblance to 

 the bears, and to the extinct Hyccnodons ; but that its distinct scaphoid 

 and lunar bones, and flat claws ally it to other forms of Mammalia, show- 

 ing it to be a more generalized type of the order than either of the 

 above. The peculiar approach of the lower canines is a special modifi- 

 cation for peculiar habits, which I suspect to have been the devouring 

 of the turtles which so abounded on land and in the waters of the same 

 period. The slender symphysis could most readily be introduced into 

 the shell, while the lateral ])ressure of the upper canines with the lower, 

 w'ould be well adapted for breaking the bony covering of those reptiles.! 

 It is not unlikely that this genus, Ulesonyx, Qnd i^oss'ihlj Ryocnodon form 

 port of the lost series which terminated in the Seals of the present. 



Synoplotherium lanius. Cope. 



Proceed. Amer. Philos. Soc, 1872, p. 433. 



The cranium of this species is rather less than that of the gi^izzly 

 bear, while the other bones do not indicate so large an animal. 



Ileasm'ements. 



M. 



Leugtli glenoid cavity 0. 045 



Width. glenoid cavity 025 



Diameter zygomatic fossa 058 



Width opistiiotic inside for. stylohyoideum 014 



Diameter meatus auditorius extcruus 012 



Diameter cavum tympani 009 



Length ramus mandibuli preserved ' 228 



Length of series of seven molar teeth 131_ 



Length of last molar crown 0155 



Width of last molar crown 0080 



Length of penultimate crown 0215 



Width of penultimate crown 0100 



Length exposed part of inferior canine 024 



Length exposed i>avt of superior canine 032 



Length exposed part of outer npper incisor 023 • 



Diameter triturating-snrface inferior canine 028 



Diameter tritvirating-surfaco do., transverse 0166 



Diameter superior canine, (antero-posterior) 024 



Diameter of the two inner incisors 010 



Diameter of exterior incisor, (oblique) 010 



Diameter symphysis mandibuli 044 



Diameter uareal orifice 040 



Depth narcal orifice 031 



Dejith mandibular ramus atM. 6 049 



Thickness below of ramus at M. G 014 



Length of a superior molar crown 020 



* See Professor Flowei-'s Osteology of Mammalia on this point. 

 + See Proceed. Amer. Philos. Soc.,'l872, p. 484. 



