Cope. ] 488 (Sept. 17, 
the inner lobe of the fourth superior premolar of the ruminants. The 
general character of the true molars is that of Phenacodus. Parts of two 
or three individuals of this species have come into my possession, one of 
which includes nearly all of the molar dentition of both jaws. The 
external cusp of the superior premolars is compressed conic, and the in- 
ternal cingulum extends to its anterior base in the second, third, and 
fourth. The crown of the last true molar is about as long as wide, while 
that of the first is wider than long. Each supports seven cusps; two 
subconic external, and one large median internal, which is connected by 
ridges with a small anterior and posterior median. Then there are a small 
anterior and posterior internal, making three internal. The internal crest 
is distinct from the principal cusp in the inferior premolars III and IV, 
but unites with it in the II; it supports on the IV an anterior, a median 
and a posterior cusp, the latter forming part of the rather narrow heel. 
The true molars I and II have seven tubercles, the four principal ones, 
and three smaller, one anterior, one posterior, and one median. On the 
third the posterior forms a large heel. All of the molars, but especially 
the premolars, have the enamel thrown into sharp vertical parallel folds, 
ina manner I have not seen in any other mammal. Length of six superior 
molars .067; length of three true molars .029; length of base of third 
premolar .012 ; width of do. .012; width of base of first true molar .010 ; 
do. of third true molar .009; length of do. .010. Length base fourth 
inferior premolar .012; width do. .010; length of third true molar .0115 ; 
width of do. .009. The teeth indicate an animal of the size of the 
peccary. 
ANISONCHUS SECTORIUS, gen. et sp. nov. Char Gen. This is derived 
from the superior P-m. IV and M. I and II, and from all the inferior mo- 
lars of three individuals. ' The superior teeth are accompanied by a ramus 
mandibuli, which contains alveoli of all the inferior molars, and the 
crowns of the P-m. IV and M.II. The leading characters have been 
given above. The inner posterior lobe is more prominent in this genus 
than in any of the others, and has a V-shaped apex. It projects further 
inwards than the anterior inner lobe. It is represented by a mere tubercle 
of the cingulum in Mioclenus. In the lower jaw the last premolar is quite 
simple, consisting of a principal cusp, and a non-cutting heel. The 
second true molar has intermediate anterior and posterior cusps. The ge- 
nus differs from Pantolestes in the more numerous tubercles of the molars, 
and in the fact that the anterior inner tubercle of the true molars is not 
double. It may, however, be allied to that genus. 
Char. Specif. The fourth superior premolar covers a larger base than 
either of the true molars. The external cusp has a base extended antero- 
posteriorly, but the apex is conical, and there are no basal tubercles. The 
inner cusp has a crescentic base as in Catathleus, but the apex is nar- 
rowed and compressed conic. The external tubercles of the true molars 
are subconic, and do not develop any external ridges. They are connected 
by the crescentic slightly angular crest, whose apex forms the inner ante- 
