L PLIOGONODON. 103 
naturally terminated in a truncated manner; the enamel forming an abrupt ring 
surrounding a shallow depression of the dentine. The specimen to the extreme 
edge of the broken base is everywhere invested with thin, 
shining, and nearly smooth enamel, being only marked by No. 36. 
feeble longitudinal striation and stronger transverse ridges of 
growth. 
In shape the tooth is conical, strongly compressed from with- 
out inwardly, and has its broad surfaces defined before and 
behind by finely denticulated trenchant borders. In transverse section it forms a 
long ellipse with very acute poles, as seen in the outline, No. 35. 
The length of the specimen in its present condition is two inches; the breadth 
just below the middle, where it is unbroken, is thirteen lines; and the thickness in 
the same position is seven lines. 
Whether the tooth belongs to the same Reptile as some of the bones described 
in the preceding pages can only be conjectured, and under the circumstances I have 
indicated it under the name heading the present chapter. It may belong to Disco- 
saurus. or Cimoliaswurus, but the question can be determined only after further 
discovery. 
PLIOGONODON. 
Pliogonodon priscus. 
Pliogonodon priscus, Leipy, Proceedings Academy Natural Sciences, Philadelphia, 1856, 255. 
Pliogonodon nobilis, Lewy, Emmons, Report North Carolina Geological Survey, 1858, p. 223, figs. 43, 44.! 
Under the above name I described the mutilated crowns of two teeth submitted 
to my inspection by Prof. Emmons, who obtained them from a Miocene deposit of 
Cape Fear, North Carolina. ‘The specimens are, nevertheless, suspected originally 
to have belonged to the Green-sand formation. ‘Their character I have not ascer- 
tained, and though I suspect them to have an affinity to Mosasaurus, they may be 
Crocodilian. 
The specimens are elongated conical, in transverse section circular. One of them 
is straight, the other feebly curved. They are provided internally with acute ridges 
or carine, defining the inner and outer surfaces of the crown, which is subdivided 
into numerous narrow planes diversified with a few vertical interrupted plicze 
more numerous on the inner surface. The base of the crown is hollowed; the 
dentine is fissured in concentric lamine, and the enamel is minutely wrinkled. 
When perfect the crowns measured about two inches in length, and three-fourths 
of an inch in diameter at base. 
1 The change of name I cannot account for except through inadvertence. 
