Cope. | 194 [Nov. 2, 
the horizon of the Dakota of the Eastern Rocky Mountains near the Ar- 
kansas River for other indications of extinct life. His search has been re- 
warded by the finding of several species of reptiles of interesting charac- 
ter, which it is the object of the present paper to describe. 
CAULODON DIVERSIDENS gen. et. sp. nov. 
This large saurian is represented by ten teeth found together, but sepa- 
rated from the cranial bones, and in a more or less broken condition. I se- 
lect four of these exhibiting the characters most clearly. 
Char. gen. Fang of the tooth of great length and hollow, and 
contracted at the base. It is without excavation for successional tooth. 
Crowns of the teeth of different forms in different portions of the jaw ; the 
posterior are like the bowl of a spoon ; others have a similar form but 
are more compressed, having double lateral ridges, while the crown of an- 
other, supposed to be an incisor, is little wider than the root, and has the 
section an oval with one side less convex than the other. All are coated with 
an enamel-like layer of considerable thickness which extends on the fang 
in some of the teeth. None of the crowns present cutting edges. 
The characters presented by these teeth are quite distinct from anything 
hitherto found in North American Saurians. The absence of indication of 
the successional teeth is remarkable, and in connection with the contrac- 
tion of the base of the root, suggests that the mode of succession of teeth 
approximated that exhibited by the Mummalia. 
Char. specif.—The roots of all the teeth-are cylindric. The crown 
of the posterior tooth is convex on one (the external) side, and concave 
on the other. The convexity is increased by a contraction of the ex- 
ternal surface near and parallel to each border. The concavity is divided 
by a longitudinal rib which disappears at the base. This edge of the 
crown is obtuse, as is also the apex. The outline of the apex is rather 
broadly acuminate. The enamel is closely and strongly rugose, longitudi- 
nally on the base, transversely at the edges, and reticulately on the middle 
portions of the crown. 
Measurements. M. 
Length of crown with portion of root..............-. 0.120 
Diameteror root at middle:tecerectime-. 02s cee oe OD 
Length of crown...... sale Bins stelekalel aol mates eiskete ssolore eiateieey aa OOO) 
Diameter of crown (dompitiiciinalercarcescmecirtta ety aes 
Grams vensetesettn. te so. os etel Ue 
The crown of the second tooth is a little less expanded laterally, and has 
a greater transverse diameter. The outer side is more convex, and there 
are two marginal ribs on the basal half of the crown, The interior are 
not strictly marginal, but are situated within the exterior ribs. Both are 
very obtuse, and they are separated by a shallow groove. There is no 
median longitudinal rib. 
7 Measurements. M. 
{ antero-posterior...,...  .026 
Diameter of crown at middle t 018 
CLAMS VELSC ey eee rena 
