330 A MEMOIR ON THE EXTINCT 



Admeasurements of the Fragment of Cranium of Dicotyles depressifrons. 

 Length of os frontis, ...... 2 inches, 9 lints. 



Estimated length from inion to ossa nasi, 



Distance between orbito-frontal foramina, ... 



Breadth of ossa nasi at angular processes of os frontis, 



Breadth of ossa nasi at upper end of intermaxillaries, 



Distance from latter to angular processes of os frontis, 



In company with the fragment of cranium just described as expressive of Dicotyles 

 depressifrons, there also was found a fragment of the left side of the lower jaw contain- 

 ing a portion of the corresponding canine tooth, and the distal extremity of a left canine 

 possibly belonging to the same individual as the former. 



The specimens indicate a larger species than those recent, and both belonged to an old 

 individual. 



The fragment of jaw along the course of the canine alveolus externally is very convex, 

 and just posterior to the symphysis is ten lines thick, and from the base to the edge of 

 the hiatus, a little posterior to the position of the mental foramen, measures fifteen and 

 a half lines. The portion of the fang of the canine remaining in the alveolus at its broken 

 extremity has the dental cavity nearly obliterated. In transverse section the fang of the 

 tooth is quadrilateral, with its longest diameter antero-posterior; anteriorly it is narrow- 

 est and convex; externally it presents a projecting longitudinal ridge; posteriorly a longi- 

 tudinal groove; and internally is convex posteriorly but longitudinally depressed ante- 

 riorly. 



The distal fragment of tooth presents the same relative proportions and form as the 

 fragment of fano; retained in the alveolus. It of course becomes in section trilateral, as 

 in existing species of Dicotyles. The end only, of the specimen, which in curve is two and 

 three quarter inches long, has enamel upon it: internally for about one inch, external';.- 

 for ten lines, and the body of the tooth, with the exception of a remaining portion of the 

 pulp cavity about one-third of a line in diameter, is a solid rod of dentine. The greatest 

 antero-posterior measurement of the fang is eight lines, and that transverse six lines. 



Other fragments probably belonging to Dicotyles depressifrons. 

 Some other specimens presented by Dr. Le Conte to the Academy, which may be con- 

 sidered as belonging to Dicotyles depressifrons, are as follow: 



1. Distal extremity of both ossa humeri: slightly more robust than in Platygonus. 



2. Left os femoris, like that of Dicotyles torquatus, but larger; its length being seven 

 inches and its circumference at the middle of the shaft two inches and a quarter. 



Besides these, there are fragments of the second right metacarpal, left os innominatum, 

 and left tibia, also a scaphoid and cuboid,* and two first phalanges and one second phalanx. 



The specimens upon which Dr. Le Conte proposed the Protochcerus prismaticust consist 

 of an inferior canine, and a first true and a portion of a last molar of the right side, most 



Irts and Sciences, vol. 3, pi. iv. fig. 25, 26. 



+ Am. I. nun. S.i >,,]. v., p. l(i. r >; l'roc. Acad. Nat. Sri., vol VI. p. 5. 



