300 O. C. Marsh—New Tertiary Reptiles. 
gated, but less so than the dorsals. The distal caudal verte- 
bre are slender, but not materially compressed. The limb 
bones preserved resemble those of the Iguanas. The remains 
peerres of this species indicate an animal about four feet in 
ength. 
Measurements. 
Space occupied by three lower teeth,.........+6+-ee-0e5 Loe 
Length of dorsal vertebra from edge of cup to end of ball, 16° 
WAGED Of ATHCUIAE CUD,. o>. ~d0csc es oe opens svrenens teat 11° 
PPR GU WAG) 0s cre i ee eet on eens tases 5 oe eee hee 10°2 
Expanse of anterior zygapophyses,..........++e-++-008: 
Expanse of posterior zygapophyses,....-....+-+++ee eee 17 
Expanse of small intermediate processes,............+++ 4°5 
Length of first sacral vertebra,............cce0e socees 13 
Width of cup,........ Weis ak Fuleee dive obee een bbe eee 6 
BONO OF Brat COG, 26. 5 PN a ees ba ENS 132 
The type specimen of this species was found by the writer, 
t 
last September, at Grizzly Buttes, Wyoming. The geologi 
horizon is Eocene, or possibly Upper Miocene. 
Thinosaurus leptodus, sp. nov. 
This species, which was somewhat smaller than the one 
above described, is indicated by the more important parts 0 
two skeletons, and some isolated remains of other individuals. 
U 
over the lower half, at least, of the crown. There is a distinct 
cutting edge in front, but none behind on the lower part of the 
teeth observed. The vertebrae are very similar to th ; 
paucidens. The articular cup is transversely elliptical, and 18 
pacar depressed above for the neural canal. The two sacral 
vertebrae are ankylosed. Both are short, and have a deep 
as on the lower surface of the expanded diapoP 
The pelvic arch is very similar to that in the Iguanas, 
ilium is pointed at its upper extremity. The caudal vertebre 
ave the chevrons situated about one-third the length of the 
centrum from the end of the articular ball. The tail was long 
and slender. 
Measurements. ; 
Space occupied by three lower teeth,...........- s+ ++" ibe 
ntero-posterior diameter of crown of lower tooth,....--> 2°5 
Transverse di he ber as nek oe en je enals eles a8 1 
