ROOM III. TEETH OF THE HYL^OSAURUS. 327 



gradually enlarges into a crown of an obtusely lanceolate 

 form, convex in front, slightly depressed behind, and termi- 

 nating in an angular rounded apex, the margins of which 

 are generally more or less worn, as if from detrition (Lign. 

 70.). The crown is solid, but the fang encloses 

 a small pulp-cavity ; the surface is enamelled, 

 and covered with very fine longitudinal striae ; 

 the base in every specimen appears broken 

 transversely, and has not a smooth surface, as 

 if it had been loosened by absorption, and shed 

 naturally. The fang never presents an appear- 

 ance of lateral adhesion, as if it had belonged to 

 a pleurodont lizard. 



Transverse sections of these teeth expose a 

 simple, central, medullary canal, the upper 

 part of which is generally filled with the ossi- 

 fied pulp ; this is surrounded by a mass of 

 firm dentine, with extremely minute calci- LlG *- 7 .- TOOTH 



,1 j. ,. /. ,1 , OF A REPTILE PROM 



gerous tubes radiating from the centre to TILGATE FOREST: 

 the periphery of the tooth, that is invested ^*s* s E 

 with a relatively thick coat of enamel, in (not. tize.j 

 which no structure is apparent. 1 



The reference of these dental organs to the Hylaeosaurus 

 must not, however, be deemed conclusive, until confirmed by 

 the discovery of similar teeth attached to a jaw, in connexion 

 with other parts of the skeleton. 2 



The locomotive organs of the Hylseosaurus are but im- 

 perfectly known ; a humerus, one phalangeal bone, and 

 fragments of the fibula, are the only remains of the extremi- 

 ties that have come under my observation. 



The Hylaeosaurus, so far as the size and form of its body 

 may be inferred from the remains of the skeletons hitherto 

 discovered (for of its head and jaws nothing is at present 

 known), probably attained a length of from twenty to thirty 

 feet. The body was broader than high, and terminated in a 

 long, slender, flexible tail ; the limbs were relatively short ; 

 the skin was studded with scutes and tubercles ; and a row of 

 very large, thin, angular spines extended down the back, and 



1 See " Medals of Creation," PI. VI. fig. 6*. 



_" Phil. Trans." 1841, p. 144, PI. VT. figs. 9, 10, 11. 



