The American Naturalist. 
General Notes, 
GEOLOGY AND PALEONTOLOGY. 
Notes on the Dinosauria of the Laramie. — Pteropelyx 
GRALLiPEs gen. et. sp. nov. This dinosaur is represented in nay collec- 
tion by the greater part of the skeleton of an individual found by Mr. 
J. C. Isaac near Cow Island, Montana, on the upper Missouri, 
in 1876. I have, as yet, detected no part of the skull or teeth 
in the collection. The generic characters are seen especially in the 
pelvis, of which the right half is nearly completely preserved. The 
ilium is quite elongate and compressed, terminating in flat, narrow- 
plates both fore and aft. The pubis is slender, and its shaft is very 
small and short, while its pectineal process is extremely long, and ex- 
panded distally in a vertical plane, reaching in the specimens anterior 
to the line of the anterior extremity of the ilium. The inferior bor- 
der of the acetabulum is thin. The ischium is also very slender, and 
is coossified proximally with the pubis, and is thence in close contact 
with it for the rest of its length. The astragalus is not united with 
the tibia, and the latter has no facet for the fibula on its distal surface. 
The feet are robust and constructed like those of Hadrosaurus, and 
there is a fourth digit, which is much shorter than the others on the 
posterior foot. Long bones solid. 
This genus differs from the known Agathaumidse in the very different 
form of the ilium, which is hadrosauroid in form. From both Hadrosau- 
rus and Diclonius it differs in the probably elongate anterior limbs, 
which are indicated by the very large pectineal processes, which re- 
semble the pelvis of Crocodilus, while the pelvis and ischium are so 
slender as to be almost functionless. The animal was thus apparently 
quadrupedal. The absence of the fibular facet of the tibia distinguishes it 
from the Diclonius mirabilis, but this is apparently wanting in the 
Hadrosaurus foulkei Leidy. The genus Pteropelyx displays characters 
between the Hadrosauridse and Agathaumidse. The genus Cionodon 
Cope, which is principally known from teeth, remains to be com- 
pared with it, as well as Dysganus, which is also known only from teeth. 
Char, specif. This reptile is about the size of the Hadrosaurus foulkei 
Leidy, as the measurements below given will indicate. The anterior 
process of the ilium is rather longer than the posterior, is more com- 
