O. C. Marsh—New Vertebrate Fossils. 255 
The crowns of the teeth are apparently compressed, and inserted 
in distinct sockets. The femur has the characteristic third tro- 
chanter, and is shorter than the tibia. 
The principal dimensions of this pigmy Dinosaur are as 
follows : 
Space occupied by five teeth in lower jaw .-. .----- 13° ™™ 
Depth of jaw below last tooth -..../.2..-.. 222. 10° 
Length of femifs/eus 00s isle ie se ee 
Distance from head to middle of third trochanter.... 25° 
Length of tibiaies oy -6 oc seed wei asd amet 458 75° 
Least, diameter of shaft... ci.s5 nc coda ve htt cece 
The geological horizon of this unique fossil is probably 
Jurassic, but possibly in the lower part of the Dakota group, 
which I regard as the equivalent of the Wealden of Europe. 
Nanosaurus victor, sp. nov. 
length. The remains at present known indicate an animal 
about as large as a fox. 
Apatodon mirus, gen. et sp. nov. 
One of the most interesting specimens hitherto found in the 
Rocky Mountain region, is a portion of a lower jaw with the 
last molar in place. This fossil is widely different from anything 
yet described, and its exact affinities are d ul. The frag- 
ment pertained to an animal about as large as a Tapir, and the 
general appearance of the specimen at once suggests the mam- 
malian type. The tooth most resembles, in form and superior 
surface of crown, that of a typical Suilline. The structure of 
the tooth, however, is different, and the fangs are, in part at 
least, codssified with the jaw. 
is specimen was found near a locality where Dinosaur 
bones were abundant, and it is possible it may belong with 
that group. The jaw, however, is very unlike any correspond- 
ing jaw of a Dinosaur, so far as now known. This tooth 
measures about 41™™ in length of crown; 20™™ in transverse 
diameter, and 8™ in height. The geological horizon is Lower 
Cretaceous or Jurassic. 
