50 M. G. MEHL 
nothing can be determined concerning those points bearing on 
the less well-established relations of the various elements. The 
palate surface has been crushed and lost in part and only the 
proximal end of the right ramus of the lower jaw is preserved. 
A few sutures can be definitely determined, chiefly those of 
the dorsal surface back of the orbits. In these no departure from 
the arrangement as shown by Douthitt* is noted, but the doubtful 
portion about the orbits and nares can be neither verified nor 
disproved. In its general appearance there is nothing to distin- 
guish this skull from any other of a dozen that have been referred 
to D. magnicornis. Although the posterolateral horns are broken 
off near the tips they are undoubtedly of the bluntly pointed, 
non-curved variety. ‘The posterior border of the skull is broadly 
Fic. 2.—Diplocaulus primigenius: scapular process of right clavicle from the 
inner side. Natural size. 
concave. None of the details such as the forward extent of the 
frontal and the arrangement of the vomerine teeth as stressed 
by Case? can be determined. The sculpture of the facial region 
is decidedly not radial. 
The length of the skull along the median line is 116 mm. The 
tabular horns project back from the posterior border of the skull 
at the median line a distance of 78 mm. and extend 338 mm. 
from tip to tip. 
The borders of the orbits are largely restored, but the indica- 
tions are that these openings were above the average in size, 
possibly as much as 17 mm. or more in diameter. 
The possibility of a gill chamber beneath the broad base of the 
posterolateral horns has been pointed out by Williston, Douthitt, and 
others. The notch made by the more or less abrupt ending of the 
Herman Douthitt, ““The Structure and Relationships of Diplocaulus,” Contri- 
butions from Walker Museum, Vol. II, No. 1 (1917). 
2 (OD, Cilten, Jo Bite 
