134 



E. C. CASE 



Following is a description of the bones of the skull in detail. 

 The basioccipital. — The basi-occipital carries a widely oval, 

 depressed condyle with a concave articular face. Laterally it 

 passes into the exoccipital without appreciable sutures. It is impos- 

 sible to make out the foramina. 



The basis phenoid. — 

 This bone has much 

 the general form of the 

 same bone in the Pel- 

 ycosauria (Baur and 

 Case, 1899 ; Case, 1905). 

 It has the expanded 

 posterior end where it 

 unites with the basi- 

 occipital, and a shallow 

 concavity in the pos- 

 terior portion of the 

 mid-line of the lower 

 face. The bone differs 

 from the basi sphenoid 

 of the Pelycosanria in 

 two particulars that are 

 of great interest. (1) 

 There is no anterior 

 rostrum ; the anterior 

 end of the bone is 

 rounded between the 

 large basi-pterygoid 

 processes, and there is 

 no trace of any median 

 process or of any rugosity. (2) The lower surface is not perfdrated 

 by' the twin foramina of the internal carotid arteries. 



It is impossible to determine the limits of the bones of the brain 



surface permitted the acid to work under the paraffin and damage the bone. When 

 the specimen was cleaned from the matrix, the paraffin was readily removed by boiling 

 the bones in water. The action of such solvents as xylol was not satisfactory in 

 removing the paraffin. 



Fig. 5. — Restoration of the palatal surface 

 of the skull from specimens Nos. 1076 and 1078. 



