NEW PERMIAN VERTEBRATES 639 
forward as the orbital margin. On the right side the upper margin 
of the vacuity, as stated, is not preserved, but the natural rounded 
border of the opening is found on the lower and partly on the front 
side, giving, with the left side, practically the outline of the vacuity 
throughout, save at the narrowed posterior end. ‘The cavity was 
oval in shape, about twenty millimeters in length, looking outward, 
and a little upward and forward. ‘There remains the bare possibility 
that the enlarged vacuity was connected by a slender and sinuous 
isthmus with the outer posterior margin of the skull, but I do not think 
so. In position, it is seen that the fenestra is nothing more nor less 
than a greatly elongated and closed epiotic notch, and this interpreta- 
tion is confirmed by the disposition of the bones on the under, palatal 
side of the skull. Other genera of stegocephs have the epiotic notch 
closed posteriorly, but I know of none in which it extends nearly so 
far forward as it does in this genus. As an epiotic vacuity it conveys 
the suggestion that the origin of the lateral temporal vacuity in 
the double-arched or saurocrotaphic reptiles has arisen, not by a 
natural trephining of the skull wall, but by the inclusion of an epiotic 
notch. From the fact that the so-called squamosal bone borders the 
vacuity above, it would hardly seem to be homologous with the 
superior temporal fenestra. However, it is by no means sure that 
the superior bone is the real homologue of the squamosal of the 
higher animals. I have followed Baur in so considering it, but I by 
no means believe that its squamosal or supratemporal character has 
yet been demonstrated. 
The sutures, for the most part, in the skull are indistinguishable 
or distinguishable with difficulty from the cracks. On the upper 
surface of the table, however, they are very conspicuous, as shown in 
the illustrations. The parietals, it is seen, are rather small bones, 
uniting by a transverse suture with the so-called supraoccipitals 
behind.t| The shape of the postfrontals is clearly shown, but the 
postorbitals are indeterminable. Nor can I make out the limits of the 
1 It has long been known that these so-called supraoccipitals of the stegocephalan 
and cotylosaurian skulls are not the real supraoccipital of the mammals and higher 
reptiles, but are membrane bones. Perhaps the best name that has yet been applied 
to them is that of Broom—the postparietals. In a later paper I shall figure both the 
cartilage supraoccipital and the membrane supraoccipitals in the same specimen, not 
even suturally united. 
