232 PROCEEDINGS OF THE NATIONAL MUSEUM VOL, 92 
U.S.N.M. No. 15816: Nearly complete articulated skeleton, lacking most of the 
tail, worked out in relief in the matrix. Collected by George F. Sternberg, 
1938. 
U.S.N.M. No. 15817: Articulated hinder portion of the skeleton of a very large 
individual ; 7 presacral, 2 sacral, and 22 caudal vertebrae in series; pelvis and 
both hind limbs and feet complete. Collected by George F. Sternberg, 1938. 
U.S.N.M. No. 15818: Fragmentary dentary; 8 presacral vertebrae; both humezi, 
left complete; both radii; an ulna; left scapula and coracoid; left clavicle; 
both ilia; both ischia; one pubis; numerous foot bones. Collected by George 
F. Sternberg, 1938. 
U.S.N.M. No. 15819: Series of 18 articulated vertebrae (2 sacrals, 9 caudals, 7 
presacrals) ; incomplete lium; right femur; tibia and a part of tarsus and 
foot; left fibula, tibia, tarsus, and part of left hind foot; numerous frag- 
mentary vertebrae. Collected by Smithsonian Paleontological Expedition, 
1938. 
THE SKELETON 
In the pages to follow there is given a detailed description of prac- 
tically the complete skeletal anatomy of Polyglyphanodon. Since the 
manuscript descriptive of the skull and skeleton and most of the pen and 
ink illustrations were prepared prior to the discovery of the very com- 
plete skeleton (U.S.N.M. No. 15816) shown in plate 25, it has been 
deemed expedient to retain the less perfect individual (U.S.N.M. No. 
15477) as the type originally selected and to designate the other as the 
paratype. This somewhat unusual procedure was decided on, not only 
for the reasons mentioned above, but because of the desire to retain 
the better specimen in its articulated state in relief in the original 
matrix. This treatment of the specimen renders it unavailable for 
proper detailed illustration, or for complete description of the in- 
dividual bones. 
The paratype, as shown in plate 25, is lying prone on its belly, with 
the ribs distended and regularly spaced on each side of the line of verte- 
brae. The articulated limbs and feet are stretched out free of the body. 
The axial skeleton is practically complete from the tip of the skull to 
the eighth caudal vertebra. Only the twelfth vertebra from the skull 
and the tail beyond the eighth caudal vertebra are missing. 
That the twelfth vertebra is lacking is indicated by a gap in the series 
and also by the presence of portions of both ribs that formerly articu- 
Jated with it. All the elements of both the pectoral and pelvic girdles 
appear to be present, but some of these have been damaged by crushing 
and others cannot be exposed in their entirety because of the overlying 
spinal column. 
The more important structural features of the skeleton displayed 
only by this specimen are: The complete presacral formula of 29 
vertebrae; complete perforate clavicle; complete interclavicle; and 
complete digital formula of the manus. The skull is in more perfect 
preservation than the type and has furnished important supplemental 
information that has been incorporated not only in the descriptive 
matter but in the illustrations as well. 
