410 O. C. Marsh—Notice of New Fossil Reptiles. 
These characters, with others mentioned below, indicate two 
distinct families, which may be called Nothodontide and Sphen- 
acodontide, from the typical genera here described. 
Nothodon lentus, gen. et sp. nov. 
This genus of Reptiles may readily be distinguished by the 
dentition. In each separate premaxillary there are two slender 
pointed teeth. In front of the maxillary there are one or two 
similar teeth, followed by a number with narrow transverse 
crowns, resembling in form the premolars of some carnivorous 
. These crowns, when unworn, have a central cusp, 
and on each side a tubercle, somewhat like that on the premolars 
of the genus Canis. In the present species the first and last of 
the transverse teeth are smaller than the middle ones. The 
aengue Of Migiivary bone 2... et Pe coe 
Space occupied by ten maxillary teeth ---- .--- -- 55° 
Height of crown of second maxillary tooth -_-. -- 14° 
Height of crown of third maxillary tooth .-..... 9% 
Antero-posterior diameter............---...--. 3 
araGaverse diameter cc. ccsci) cco 604m vce-% 8 
Antero-posterior diameter of eighth tooth ------- 5 
ranavorse Giameter. soci. cn sw. bcs cin eee 15 
The present species was about five or six feet in length, and 
herbivorous in habit. It was apparently slow in movement, 
and probably more or less aquatic. The remains at present 
own are from New Mexico. 
Sphenacodon ferox, gen. et sp. nov. : 
I the present genus the anterior teeth are somewhat like 
those of the reptile described above, but the posterior, or more 
characteristic ones, are totally different. The crowns are much 
compressed, and have very sharp cutting edges, without crenula- 
tions. In the present species the carnivorous teeth are crowd 
together, and the crowns placed slightly oblique, and twist 
The jaws were comparatively short and massive. The rami of 
the lower jaws were apparently united. by cartilage only, and 
the symphysis was short. The vertebra are deeply biconcave. 
Measurements from the type of this species are as follows: 
Length of dentary bone: 221 2: os. eee is 1502 
Space occupied: by teeth. 3. oi i 130° 
Extent of four anterior caniniform teeth... ___- 25° 
