PROM THE KIMMEEIDGE CLAY. 455 



EXPLANATION OF PLATES XVIIL, XIX., XX. 



All the figures are two thirds of the actual size, except those of the jaws, which 

 are X 2, and figs. 8, 9, PI. XX. which are diagrammatic. 



Plate XVIII. 



Fig. 1 (No. I. 10). View of undersurface of part of vault of skull. /, frontal 

 bone ; ff, postfrontal ; p, parietal. 



2. The upper surface of the same fragment. The lettering is the same. 



3. Fragment of occiput, fm, foramen magnum ; so, supraoccipital. 



4. The under surface of a fragment of the base of the skull, oc, occipital 



condyle ; Bo, basioccipital ; Bs, basisphenoid ; o, carotid groove ; 

 h'p, hypophysial pit. 



5. The upper surface of the same piece. 



6. Fragment of the right maxilla (outer surface) showing three teeth : — 1, 



a mature germ, not yet in wear ; 2, a crown, which was in full use at 

 the death of the animal ; the free edge is not in the line of actual wear, 

 but an accidental fracture ; 3, a fang extended considerably beyond 

 the border of its socket. 



7. Another fragment of a maxilla, showing : — s, an empty socket ; /, the fang 



of a tooth, of which the crown had been fully extended, and in full 

 wear. It tapers to a blunt point ; and the pulp-cavity, large at the 

 junction of the fang and crown, is contracted to a small opening at 

 the free end of the fang, g, a mature germ, at the base of which are 

 remains of an almost completely extended fang. 



8. A fragment of the dentary part of mandible. 1, 3, 5, fangs, of which 



the crowns must have been almost worn away ; 2, 4, 6, crowns of 

 teeth in full wear; 7, 9, 11, germs, of which about half is extruded 

 beyond the inner parapet of the aveolus ; 8, 10, smaller germs, of which 

 only the tip is visible. 

 Figs. 6, 7, 8, are X2. 



Plate XIX. 



d, diapophysis ; p, parapophysis ; x^rz, prsezygapophysis ; fsz, postzygapo- 

 physis ; a, anterior articvilar surface. 



Fig. 1. Front view of cervical vertebra (ii. 3). 



2. Posterior view of the same, 



3. Side view of the same. 



4. Inferior view of the same. 



5. Side view of a thoracic vertebra (ii. 11). 



6. Side view of a lumbar vertebra (ii. 20). 



7. Anterior view of the same. 



8. Posterior view of the same. 



9. Side view of a caudal vertebra, from near sacrum (ii. 28). Centrum 



oblique (ii. 28). 



10. Side view of a caudal vertebra (ii. 32) posterior in position to ii. 28. 



11. Side view of a caudal vertebra from a part of the tail where the trans- 



verse process has disappeared (ii. 41). 

 12 (ii. 53) & 13 (ii. 58). Vertebrae from very near the end of the tail. 



Plate XX. 



Fig. 1. The last lumbar vertebra and the sacrum, seen from below. 



2. The same, seen from above. 



In both, 1 1, last lumbar ; \s 2&, 1st & 2nd sacral centra ; ne, neural 

 canal ; ng, nerve-groove. 



3. The OS calcis, its outer surface. 



