262 
ACTiNorTEExerx. 
exhibits a characteristic gentle curvature, with the coi 
cavity upwards • and its outer face is remarkably convex 
and smooth, with an incurved lower border. ( )f the tw^ 
enlarged mandibular teeth, one occurs on the right, >u 
both are preserved on the left ; they are slightly recurve * 
apparently compressed to a sharper edge in front t >a 
behind, and the basal part of tho outer face is mai e ^ 
very delicate vertical striations. Six similar, but relative^ 
small and short teeth, are preserved posteriorly 011 
right, while four remain on the left ; of those on 
right, the hindermost is the largest. Another 8l,n ^ 
though small tooth is seen just in front of the cn ur ”^ 
teeth on the left, and between this and the anterior 
of the jaw there is a diminishing series of recUr ar (- 
dcnticles. At the hinder end of the right chee* 
of the quadrate bone is exposed ; and imnux ia . 
behind this there is the much-thickened anterior b° ^ 
of the preoperculum (j>.op.). tap 1 0,1 
P ■ 4512. A still smaller skull broken across the middle and in 
shown 
of 
respects more imperfect than the type specimen, 
the natural size from both sides and above in • nr 
narrow 
is 
uout is 
figs. 2, 2 a, 2b; English Chalk. The very ^ 
cranium, sharply compressed above the otic rc n ^ 
indicated as before ; and the remarkably acute su ^ 
especially well shown. On both sides there are re 
of extensive though delicate postorbital cheek-plat*® 
and the anterior attenuated ends of the charac^e 
premaxilla) ( pmx .) are displayed apposed to the ■ ^ ^ 
ethmoidal region (elh.), and apparentlyjustmceting m ^ ^ 
The two enlarged premaxillary teeth are partly 8 10 "^ 
both sides (i, ii), but the second on the left seems 
a little displaced through fracture. The smoot , 1 e 
mandible is much broken 
..... , but the extent of th ® 
articulo-angular element («;/■) i a 8een especially ® ^ 
right, and there are remains of the characteristic ^ 
teeth on both sides. 
Etmisldlltn Coil. 
49067. Group of remains of a small fish, comprising the ^gbral 
end of the right premaxilla, a quadrate, two V ^ er ; or 
centra, and other bones; Chalk, Kent. 
portion of the promaxilla is shown from the outer 
(PI. XIII. fig. 6) and bears tho two enlarged teetn,^ 
seem to display their normal proportions an< m 
