142 PROCEEDII^GS OP THE GEOLOGICAL SOCIETY. [Jan. 13, 



and relations to the pelvis, is, without doubt, the principal sacral 

 vertebra. The impression which it has left appears to me to have 

 been formed by the outer face of the right sacral rib. Certainly not 

 more than one of the three succeeding vertebrae, the two hindermost 

 of which are represented by little more than casts of their neural 

 canals and of the region thereabouts, can have been united with the 

 principal sacral vertebra to form the sacrum. 



On clearing away the friable remains of the original bone from 

 the hard sandstone matrix, the latter presents casts of the external 

 surface and of the neural canal of each vertebra, which, in some 

 cases, are very perfect. These casts show no sign whatever of the 

 deep pits which would correspond with well- developed transverse 

 processes ; but there is a depression at the anterior part of each 

 body of a vertebra answering to what appears to have been a low 

 tubercle for the attachment of a rib, as in existing lizards. 



In correspondence with this structure of the vertebrae, the remains 

 of a number of ribs, which have been laid bare by chiselling away 

 portions of the matrix, show no trace of a division into capitulum and 

 tuberculum at their vertebral ends. The longest of them is 4 inches 

 in length. Like the rib of a Monitor , its vertebral end is somewhat 

 expanded ; and it is so curved as to be, at first, a little concave to- 

 wards the dorsal aspect ; in the rest of its extent it is convex in 

 that direction. 



I see no remains of true sternal ribs ; but there are numerous faint 

 transverse linear impressions of a system of dermal ossifications, which 

 I conceive, answers to the so-called " abdominal ribs " of a Crocodile, 

 or to the corresponding structures in Sphenodon. These, however, are 

 better shown in another slab. 



To the anterior extremity of the block of sandstone which con- 

 tains these vertebrae (and which I shall call No. 1) fits another, 

 which bears the anterior cervico-dorsal vertebrae and the skull. The 

 latter is bent round so that its axis is nearJy at right angles with 

 that of the body. 



None of these anterior cervico-dorsal vertebrae can be clearly made 

 out; but they cannot have been numerous, and I doubt whether 

 there were altogether more than twenty, or twenty-two, presacral 

 vertebrae. 



The skull had a length, when complete, of not less than 7 inches. 

 It is about 5 inches broad posteriorly, but anteriorly narrows to a 

 deflexed and comparatively slender snout, the diameter of which is 

 not more than 1 inch. It is so disposed as to turn its ventral aspect 

 to the eye. The left ramus of the lower jaw is in place, though 

 much mutilated. The right ramus is broken away, and shows the 

 oral surface of the palate and maxilla, with the obscure remains of 

 several obtusely conical teeth. 



On the left side, a good deal of the dentary edge of the left ramus 

 of the mandible is preserved, and it is seen to be shut against the 

 upper jaw, passing on the inner side of a series of mutilated teeth, 

 which are fixed on the maxilla. The end of the snout presents a 

 very remarkable structure. The anterior portion of the edge of each 



