CIMOLICHTHYS. 



45 



Specific Characters. — Maximum width of cranium slightly exceeding one thii-d 

 of its length, and premaxilla ornamented with radiating tuberculated ridges ; length 

 of mandible about five times as great as its maximum depth. Four ectopterygoid 

 teeth, of which the two foremost are moderately slender and slightly barbed ; inner 

 and outer palatine teeth nearly equal in size, with about 10 sockets in front of the 

 enlarged postero-internal tooth ; some of the palatine teeth slightly barbed ; six 

 recurved teeth, scarcely barbed, in the inner mandibular series, the third and 

 largest situated within the anterior half of the dentary. 



Description of Specimens. — The type specimen in the Mantell Collection is the 

 greater part of the left ectopterygoid exposed from within and displaying two of 

 the barbed teeth, as shown in the original figure by Agassiz. Another specimen in 



y-^'^m ^a.A. /Jh.a.yt.^ 



FiQ. 10. Cimolichthys lewesiensis, Leidy ; diagram of jaws ; the premaxilla (pmx.), maxilla (ma;.), and 

 dentary (d.) of left side, outer aspect; the palatine (pi.) and ectopterygoid (ecpt.) of right side, 

 inner aspect. — English Chalk. 



the Willett Collection, Brighton Museum, also shows the characteristic ectoptery- 

 goid in association with the mandible and other remains, and is figured by Dixon, 

 op. cit., pi. xxxii*, fig. 10. All the other most important known specimens are 

 contained in the various collections now brought together in the British Museum. 



The general proportions of the skull are shown by the two specimens repre- 

 sented from the upper and lateral aspects in PL XII, figs. 1, 1 a, 2. The occipital 

 face is sharply bent in the middle, so that it is observed to be excavated by a re- 

 entering angle when viewed from above ; but it does not project backwards beyond 

 the exposed cranial roof. The small supraoccipital bears a large posterior crest 

 (socc), which does not rise above the plane of the flattened cranial roof; and its 



