from: the lower lias of charhouth. 



447 



On each side of the section above the basisphenoid the thin bar 

 of bone which proceeds from the squamosal is seen, and at the 

 summit the parietals with their median crest and persistent suture. 

 The other bones appear to be undeterminable ; some of them are 

 probably parts of the periotic mass. 



Dentition. — A fine series of teeth is well displayed on the left side 

 of the head. They are slender, conical, slightly recurved, and finely 

 striated from the apex for a considerable distance downwards, i. e. 

 over the crown. They vary greatly in size, the largest being those 

 in the neighbourhood of the maxillo-premaxillary suture ; an inch 

 or so behind this they begin to diminish in size, and beneath the 

 orbit have less than one half the average length of those in front, 

 while behind it they dwindle to mere pointed tubercles. 



The largest tooth present is one in the right upper jaw, behind 

 the maxillo-premaxillary suture ; it is 2*45 inches long, the distal 

 1*5 inch, or crown, finely striated, its diameter at the point where 

 the striae begin being 0*6 inch. A smaller but more perfect tooth, 

 the largest on the left side, measures 1*95 inches long ; 1-35 inch is 

 striated ; and the diameter at the commencement of striation is 

 0*5 inch. 



Those teeth which still remain exposed to view are distributed as 

 follows : — on the left side in the praamaxilla 5, in the maxilla 15, 

 in the lower jaw 13; on the right side in the prsemaxilla 3, in the 

 maxilla 11, in the lower jaw 8. The number of teeth in the left 

 praamaxilla and maxilla make the nearest approximation to the 

 numbers originally present. 



The Vertebral Column. — There is a continuous series of 66 ver- 

 tebras, of which 38 are cervical, 21 dorsal, 2 sacral, and 5 caudal. 

 The caudal series is evidently incomplete, a considerable number of 

 vertebrae being missing from the distal end. 



Cervical Vertebrce. — The first and second, as already mentioned, 

 form a confused mass adherent to the back of the skull, but from 

 the third onwards all are clearly defined and can be easily examined, 

 m. The centrum of the third is 1*12 inch long* (a.p.), 0*75 broad 

 (1.1.), and 1*4 high (d.v.), the breadth and height being measured 

 along the articular face. It is much compressed in the middle, the 

 edges of the articular ends projecting greatly, as though the more 

 yielding cancellous interior had given way under heavy pressure, 

 such as that of overlying strata ; this feature is markedly present as 

 far as the thirteenth cervical vertebra. The neuro-central suture is 

 a nearly straight or slightly tricurvate line, with the central con- 

 vexity downwards. A tricurvate ridge, with the central convexity 

 upwards, runs along the whole length of the centrum between the 

 articular edges or rims, at a level 0*4 inch below the neuro-central 

 suture ; it defines the upper edge of the nearly oval costal pit, which 

 is 0*9 inch long, 0*45 inch broad (d.v.), and obscurely divided into 

 two by a faint median longitudinal ridge or closed furrow. The rib 

 has been displaced downwards ; and its ovate-lanceolate posterior 



(a.p.) anteroposterior, (1.1.) from side to side, (d.v.) dorso-ventral. 



