328 



A MEMOIR ON THE EXTINCT 



In Dr. Le Conte's collection there is a second premolar, (PI. 37, fig. 14,) and the first 

 and second true molars, (fig. 15,) of the superior left side, which have heen referred to Di- 

 cotyles deprcssifrons,* but which correspond so closely in size and form with the teeth 

 described of Platygonus, that I think they belonged to another and younger individual only 

 of the latter. 



ADMEASUREMENTS OF PLATYGONUS. 



Fragment of Lower Jaw. 



Height from angle to condyle, - 



do of body below last molar, 

 Ant. post, diameter of last molar, - 

 Transverse do do - 



Ant. post, diameter of second true molar, - 

 Transverse, do do do - 



Isolated Upper Molars. 



Length of premolar series, - 



Fragment of Face. 

 Height of crescentic ridge of canine alveolus, ... 

 Distance from summit of the latter ridge to the upper end of the intermaxillary bone, 

 Narrowest part of face below the upper extremities of the intermaxillaries, 

 Breadth of each os nasi about middle, - 

 Height of face about one inch in advance of the molars, 

 Length of line of permanent premolars, .... 



Transverse diameter of first premolar, ----- 

 Ant. post. do second do 



Transverse, do do do - 



Ant. post. do third do 



Transverse do do do - 



Isolated Superior Canine. 

 Length of enamelled crown internally, - 



Antero-posterior diameter at base, - 

 Transverse do do - 



Other fragments, probably belonging to Platygonus compressus, and presented to the Academy by Dr. Le 



Conic. These are as follow : — 



1. Fragments of the forehead, (Mem. Am. Acad. Arts and Sci., vol. 3, plate 2, fig. 4,) indicating the breadth 

 at the post orbital processes to be three and a quarter inches. 



2. Several fragments of an os malie and hard palate. 



3. Bodies of a dorsal and lumbar vertebra, (lb., plate 3, fig. 14; plate 4, figs. 16-18.) 



4. Portion of os innominatum. 



*Pr. A. N. S ri. 3 



