132 AMPHIBIA AND PISCES OF THE PERMIAN OF NORTH AMERICA 



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.* The shape of the post- 

 frontals is clearly shown, but the postorbitals are indeterminable. Nor can 

 I make out the limits of the epiotics and 'squamosals' or ' supratemporals,' 

 though the two bones very clearly form the outer part of the table. The 

 frontal bones terminate a little in front of the orbits by a nearly transverse 

 suture, and, of course, the nasal bones form that portion between the ant- 

 orbital vacuities, as far forward as the rather small premaxillse. 



"At the very front of the rostrum there is a rather small, but perfect, 

 median, unpaired vacuity leading into a foramen in the middle of the palate 

 below. I am at a loss to say what its real nature is. If not a median narial 

 opening, I can not see why there should be a palatal opening below it. It 

 is not for the passage of teeth, as in some labyrinthodonts. A median open- 

 ing is not unknown among the Stegocephala. Dasyceps, from the Permian 

 of Kenilworth, has a large, elongate opening between the nasals, and Acan- 

 thostoma, from the Rothliegendes, has a moderately large median vacuity 

 between the large nasals and the premaxill^. 



"The greatly enlarged and elongated openings on the sides of the face 

 in front of the orbits are, in part at least, merely antorbltal vacuities; of 

 this there can be no doubt. The anterior portions, however, seem to be 

 the real nares, in position like those of Eryops, and opening into a vacuity 

 at the outer side of the palatine and vomers of the palate. A flattened or 

 concave bone is seen in the right fossa, directed obliquely backward. It 

 may be a turbinated bone. 



"The occipital condyles are parial, the gentle concave articular sur- 

 faces looking backward, a little downward, and toward each other. A speci- 

 men of Eryops in the collection shows, I think clearly, a transverse suture 

 a little in front of these processes separating them from the part in front 

 which I believe to be the basisphenoid, and just back of a pair of flattened 

 or spoon-shaped processes, corresponding to the hypopophyses of the rep- 

 tilian basisphenoid and occipital region. In front of these processes the 

 bone is gently concave from side to side. In the middle in front there is a 

 rounded heavy margin, which shows no traces of a bony prolongation, as 

 in Eryops, into the median parasphenoid. On either side in front, the basi- 

 sphenoid turns downward in a thickened process, quite as in Eryops, to 

 articulate with the pterygoids. On either side, posteriorly, from the basi- 

 occipital processes a groove runs outward and upward, bounded in front 



* " 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." 



