CnrROCENTRID^.—CTENOTHRISSID^. 
119 
49763. Imperfect jaws ; Soutlieram. Capron Coll. 
49764-65. Detached left dentary and a small skull, both frag¬ 
mentary; Lower Chalk, Amberley Pit, Arundel. 
Capron Coll. 
P. 3849. Fragmentary jaws ; Arundel. Enniskillen Coll. 
49767-68. T wo small fragmentary heads ; Lower Chalk, Dorking, 
Surrey. Capron Coll. 
25925. Imperfect left mandibular ramus and another fragmentary 
mandible, the first figured by Dixon, op. cit.., as the type 
of a distinct species, Tomognathus leiodus; Washington, 
Sussex. Dixon Coll. 
The following specimens are not specifically determined :— 
P. 6460 a. Domains of small head and opercular apparatus, remark¬ 
able for the very large size of the anterior teeth, which 
are especially tumid at the base, incurved and not fluted 
even in the apical portion; Chalk, S.E. England. The 
nutritive foramina in the dentary are large, while the 
operculum and suboperculum are covered with small pits 
W'hich have a raised border. Deckles Coll. 
47242. Fragmentary remains of a large head, exhibiting a non- 
fluted anterior mandibular tooth ; Chalk Marl, Dover. 
Gardner Coll. 
37325. Fragment of small head ; Chalk Marl, Dover. 
Purchased.^ 1863. 
Family CTENOTHDISSIDiE. 
t/ 
Supraoccipital bone prominent, but parietals partly meeting in 
the middle line; squamosal reduced and apparently fused with 
pterotic; snout not produced ; cheek-plates reduced. Premaxilla 
small and maxilla relatively large and loose, both these bones 
entering the upper border of the mouth; two supramaxillaries ; 
teeth acuminate, but feeble. Opercular apparatus complete, but 
few branchiostegal rays and no gular plate. Vertebral centra "well 
ossified, none with transverse processes ; ribs nearly encircling the 
abdominal cavity. Fin-fulcra absent, and simple rays in front of 
dorsal fin slightly spaced; post-temporal bones in contact with 
postero-lateral angles of cranium; post-clavicular plate overlapped 
by the clavicle; pelvic fins relatively large and advanced far for¬ 
wards. Scales thin and deeply imbricating. 
