10 Procecdiiifjs of the Royal Phijsieal Society. 



was lost on the surface. The eye was xDlaced behind the 

 angle of the moutli, and immediately behind it the integu- 

 ment was depressed and corrugated. Behind the plane of 

 tlie eye slit was the aperture of the external auditory 

 meatus, which admitted only a fine bristle. 



Only two mandibular teeth were seen. They projected 

 only |ths of an inch beyond the gum, and very slightly from 

 between tlie lips when the mouth w^as closed. This small 

 amount of projection, as compared with what is shown in 

 Mr Andrews' figure of the head of his specimen, gave me the 

 impression that my animal had not reached its complete 

 adult development. The vertebral epiphysial plates were, 

 however, for the most part ossified to the bodies. 



The upper border of the mandible in front of each tooth 

 was grooved for about 4 inches. No rudimentary teeth pro- 

 jected through the gum, neither were any found buried in 

 its substance either in the upper or lower jaw. In this 

 respect the animal differed from that examined by Eein- 

 hardt, in which three if not four small functionless teeth 

 were present on each side of the upper jaw. 



A pair of characteristic furrows was present in the sub- 

 mandibular region. About 10 inches behind the tip of the 

 lower jaw they were almost continuous with each other 

 anteriorly, the interval between them being barely J inch. 

 From this spot they diverged as they passed backwards, so 

 that their posterior ends, which were in the same transverse 

 plane as the middle of the palpebral fissure, were 9 inches 

 asunder. Each sub-mandibular furrow was not more than 

 J inch deep, and could be opened out at its widest to 

 J inch. The skin lining it was soft, and partially wrinkled. 

 The wrinkling of the skin and the readiness with which the 

 furrows could be dilated, indicated that they could be 

 both widened out and closed, a variation in their condition 

 which is possibly associated with the state of the mouth 

 when either full of food or empty. Mr Andrews, in his 

 fiirure of the sub-mandibular furrow, makes the two limbs 

 meet anteriorly ; but in my specimen the relation between 

 them corresponded with the appearance figured by Carl 

 Aurivillius in the young male which he examined, in 



