222 
ACTINOPTEKTGII. 
Type. Imperfect ectopterygoid ; British Museum. 
The type species, Dot satisfactorily definable, with cranium 
attaining a length of about 0T5. Maximum width of cranium 
slightly exceeding one third its length, and premaxilla ornamented 
with radiating tuberculated ridges. All the teeth of the ecto- 
ptervgoid, except the few small ones posteriorly, moderately slender 
and slightly barbed; the largest tooth of the inner mandibular 
series situated within the anterior half of the dentary. 
Form. Log. Senonian and Turonian : Sussex and Kent. 
4039. Type specimen described and figured by Agassiz, loo. cit. ; 
Chalk, Lewes. This is the hinder half of the left ecto¬ 
pterygoid exposed from within. Mantell Coll. 
P. 5491. Imperfect skull and mandible, noticed by the present 
writer, loc. cit. p. 317 ; Chalk, Lewes. The specimen is 
damaged by an oblique fracture, and the rostral region of 
the cranium is obscure ; but the I'routal bones are well 
displayed and shown to extend close to the occipital 
border. Only a trace of the small supraoccipital,. with its 
hinder keel, is preserved. There is a shallow, antero- 
posteriorly elongated fossa above the otic region on each 
side. ^Fragmentary remains of the premaxilla on each 
side prove it to have been an antero-posteriorly elongated 
laminar bone, bent inwards above on its long axis, and 
I 
ornamented externally with tuberculated radiating ridges. 
The long and slender maxilla, which is almost smooth, is 
nearly complete on the left side, and extends forwards 
above the premaxilla to about the middle point of the 
latter. Neither the maxilla nor the premaxilla, as pre¬ 
served, exhibits any indications of teeth. The imperfect 
mandible is seen from beneath, and two of its large 
recurved teeth are exposed. There are also remains of 
the pterygo-palatine arcade, with several of the character¬ 
istic barbed teeth, and with marks of the oval bases 
of attachment of similar teeth which have been broken 
away. The slender ceratohyal is preserved on the left 
side; while immediately above it is exposed part of a 
laminar bone, probably entopterygoid, bearing clustered 
minute teeth.. Enniskillen Coll. 
P. 1810 a. More fragmentary skull and mandible, noticed by 
Loomis, Palaeontogr. vol. xlvi. (1900), p. 267 ; Chalk, Kent. 
The maxilla does not exhibit any teeth ; but a fragment. 
