OSTEOLOGY OF PULYGLYPHANODON—GILMORE 235 
superior process of the maxillary. The frontal contribution to the 
formation of the boundary of the external nares is damaged on both 
sides of the type skull, and this part of the restored skull has been 
drawn following U.S.N.M. No. 15816, which has this region 
completely preserved. 
Premaxillary—tThe premaxillary (pmax) has an unusually long 
spine that extends far posterior between the nasal bones. Viewed 
from above the nose is broadly rounded, the alveolar border giving 
support to six small premaxillary teeth. Laterally the premaxillary 
united with the maxillary by a straight vertical suture. Near the 
base of the spine, the border is scalloped by two small notches one 
above the other (see fig. 16). 
Ficure 17.—Skull of Polyglyphanodon sternbergi Gilmore, U.S.N.M. No. 15477, type, natural 
size, viewed from the top: exo, Exoccipital; f, frontal; 7, jugal; /a, lachrymal; mx, maxillary; 
na, nasal; 0, orbit; occ, occipital condyle; p, parietal; pin, pineal foramen; pf, prefrontal; 
pmx, premaxillary; po, postorbital; pif, postfrontal; gu, quadrate; smx, septomaxillary; 
50, supraoccipital; sg, squamosal; stf, supratemporal fossa; ta, tabulare. 
Maxillary —tThe maxillary (ma) viewed from the side is subtri- 
angular in outline and is unusually deep at the midline. The pos- 
terior end underlaps the jugal, its posterior end terminating below 
the center of the orbit. Above it articulates with the lachrymal, 
prefrontal, and nasal, interposing a slender pointed process pos- 
teriorly betwen the prefrontal and nasal bones, as in the agamid 
lizard Hydrosaurus pustulosis. This bone carries a full comple- 
ment of 18 teeth, which occupy an alveolar space 32.6 mm. in length. 
The anterior end is deeply excavated to form the posterior and 
ventral boundaries of the anterior nares. The external surface of 
the bone is smooth except for a number of small foramina, three of 
which are arranged in a row slightly above, but nearly parallel to, 
the alveolar border. 
