LOWKR LIAS. 13 



curve from the angle forward, horizontally, at first concave, then convex, towards 

 the median line, where they meet without blending at the part fractured. It is 

 not probable that the symphysis would be much prolonged beyond this point. 

 The degree of convergence of the contour lines of the whole skull, both median 

 and lateral, with the decreasing size of the anterior teeth, makes it more probable 

 that but a small proportion of the muzzle is wanting in the present specimen 

 (Tabs. IV and V). The analogy of the Iguanodon might be unsafe ground for 

 inferring as short a symphysis mandibular in Scelidosaurus, but it would accord 

 with the other indications of such a proportion of the conjoined ends of the rami. 



Dentition. Tabs. IV and V. 



The specimen of Scelidosaurus here described has been buried and petrified 

 with the mouth shut; there has been no dislocation of the under jaw, and the skull 

 shows that the teeth of the upper jaw overlapped and concealed those of the lower. 

 The crowns of both series were a little inclined inward, as shown at the fractured 

 fore part (Tab. V, fig. 2, «, b)\ this, with the similar inclination of the alveolar 

 plates, produces a feature which reminds one of that of toothless anility, or of the 

 effect of sucking in the cheeks, in man. 



The teeth are small, or of Lacertian proportions to the jaws ; they are nume- 

 rous and close set, implanted in sockets forming an uninterrupted series along the 

 alveolar border. The fang is simple, and longer than the crown, presenting a full 

 ellipse in transverse section, and projecting a little beyond the socket. In the 

 upper jaw the crown (Tab. V, fig. 3) begins by bulging outward, with a smooth 

 convexity, subsiding as it gradually expands, and dividing to be continued along the 

 middle and the margins, with intervening concavities, producing an undulated 

 surface across the broadest part of the crown. The marginal convexities or ridges 

 terminate each in a point at the broadest part of the crown; whence, the plate- 

 shaped tooth having thinned off to an edge, this is divided on each side into five or 

 six smaller points : these denticulate margins converge straight, at an angle rather 

 less than a right one, to the apex of the tooth, which is formed by the pointed ter- 

 mination of the median convexity. The crown is coated by a polished enamel, of 

 jet blackness in the fossil, smooth under the lens upon the convexities, finely 

 punctate in the hollows of the expanded part of the crown. The whole tooth in 

 the upper jaw is very slightly bent backward, with as slight an oblique twist, 

 making the hinder angle overlap the front angle of the crown of the tooth behind. 



The inner surface of four of the hind teeth of the right ramus of the jaw 

 shows a crown with a larger proportion of the serrated part, and with the borders 

 less equal, the anterior one showing as many as nine points, and the expanded 

 coronal surface is uniformly and gently convex. 



