CBANIAL OSTEOLOtlY OF THE OSTEOGLOSSIDJ3. 261 



two slender points which lie closely bound to the right and left 

 sides of the anterior half of the basioccipital. Just in front of 

 the pro-otic region a pair of strong oblique processes extend 

 from the parasphenoid outward, forward, and downward, for 

 articulation with the entopterygoid. 



Temporal and Preopercular Series (figs. 9 and 10). — The post- 

 temporal has an upper limb the anterior extremity of which 

 OTerlies the epiotic, and a deep, rod-like limb attached by liga- 

 ment to the posteriorly directed process of the opisthotic. The 

 horizontal sensory canal lies towards the ventro-external part of 

 the body of the post-temporal bone, and the bony tube surround- 

 ing the canal is continued forward towards the suprateniporal, 

 but fails to reach it. The supratemporal is rather small, and is 

 partly wedged in beneath the postero-lateral margin of the 

 parietal. It is not a sculptured bone. 



The lower part of the preopercular is sculptured. The lower 

 limb is nearly as long as the upright portion, and makes with it 

 an angle of rather less than a right angle. The inter opercular 

 is a thin flake of bone, of large size, lying on the inner surface 

 of the lower part of the preopercular. 



Gircumorhital Series (fig. 9). — In addition to the nasal bone, 

 previously mentioned, there are five bones of this series. The 

 preorbital bone has a prominent ridge running upwards along its 

 inner surface. The largest of the series is the postorbital, the 

 anterior edge of which bone is considerably thickened. They 

 are all sculptured. 



Maxillary Series (fig. 9). — The mouth, when viewed from the 

 front, is curiously square in shape, and the upper side of the 

 square is formed by the premaxillae. The two premaxillse are 

 separated by the narrow vomer, so that the middle part of the 

 upper jaw is toothless. Each premaxilla bears about thirteen 

 teeth. The number of teeth in the maxilla is about fourteen, 

 and these, like those of the premaxilla, are long, blunt, and 

 curved at the tips. The maxilla, when isolated, is seen to be 

 bent at its middle into a right angle. The horizontal part lies 

 over the premaxilla and is toothless ; it nearly reaches the 

 vomer, but does not enter into definite i-elation with it and has 

 no articular head. There is no surmaxilla. 



Mandibular Series (figs. 9 and 10). — The dentary rises high, 

 and the coronoid process is set well forward. The teeth are 

 similar to those of the premaxilla, and are about twenty-two 



