302 O. C. Marsh—New Tertiary Reptiles. 
vertebra has a groove on the lower side of its diapophyses. 
This species was probably not less than seven feet in length, 
and three or four times the bulk of Jguana tuberculata. 
Measurements. 
Transverse diameter of cup of dorsal vertebra,........--- 13° 
Transverse diameter of same vertebra between articular 
faces of diapophyses, ...+....--ee cece cece cece eeceree 29 
Transverse diameter of neural arch between zygapophyses, 16° 
22° 
mle 
Expanse of posterior zygapophyses, ......-.-+++eeeeeees 
Length of posterior sacral vertebra,........+++++eee+005 18° 
a tensyerse diameter of ball). oo 05 oo. os Sores ose ope ee 11°5 
Length of first caudal vertebra,......00..00 cece veneers 18°1 
Antero-posterior diameter of acetabular cavity,.......-++ 21: 
The type specimen of this species was found, in September, 
1870, at a Buttes, Wyoming, by Mr. C. W. Betts, of the 
Yale party of that year. 
Thinosaurus agilis, sp. NOV. 
larger species, but the basal grooves on the inner side do not 
extend up so far on the crown. The two species may ? 
readily distinguished, also, aside from the great difference 1 
size, by the anterior caudal vertebrx, which in the present spect 
men have the articular cup much more depressed. In the 
dorsal vertebree, the neural spine is quite short. The middle 
and distal caudals are much elongated. The remains preserve 
indicate an animal about two feet long. 
Length of dorsal vertebra on lower surface,....------- 10°3 ™ 
Width of articular COPics oat cas oo ae 
Width of ball. 2. coco ee 
Expanse of anterior zygapophyses,._.......---------- 9° 
Expanse of posterior zygapophyses,........-.-----.-- 8°2 
ength of first caudal vertebra,..............-..----- 73 
Width of artitnlar tipo sn ee 5° 
2°8 
Vertical diameter of cup, - - - 
Tranverse diameter of distal end of femur, ; 
The specimens on which this description is based were found, 
last autumn, near Henry’s Fork, by Mr. G. G. Lobdell, jr. 
Glyptosaurus princeps, sp. nov. 
In addition to the characters given when the genus @lypl? 
saurus was proposed,* the following, derived from a study of 
* This Journal, vol. i, p. 456, June, 1871. 
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