80 
ACTI^^0PTERTG1T. 
P. 1748. Pragmeiit of right side of head showing parts of pre¬ 
maxilla, maxilla, and dentary, with teeth ; also remains 
of a laminar inner bone of the mouth (probably ento- 
pter 3 ’goid) covered with a cluster of minute stout conical 
teeth. The premaxillary teeth are the largest. 
Egerton Coll. 
43021. Eight premaxilla, with remains of a cheek-plate which is 
ornamented with radiating lines of fine tubercles. The 
premaxilla (PI. I. figs. 4, 4 a) is shown to have been 
attached to the ethmoidal region throughout its front 
half, which is not much deepened ; and there is a deep 
longitudinal groove for the overlap of the maxilla on its 
hinder portion. The hone bears ten closelj' arranged, 
antero-posteriorly compressed teeth, two represented only 
b}’ the base of attachment, and all the others except the 
foremost having lost the enamelled crown. 
Purchased 1871. 
28424. Anterior end of small left dentary showing robust 
mandibular symphj^sis. Mantell Coll. 
P. 641. Hinder half of smaU skull with opercular apparatus, partly 
pyritised and imperfectly preserved, probably referable to 
a young individual of this species. The specimen is 
marked by Egerton as intended to be the tj^pe of the 
species Pomaphractus egertoni, Agassiz, loc. cit. 
Egerton Coll. 
39699. Eemains of equally small head, showing jaws. 
Purchased, 1866. 
incerth: sedis 
(? OSTEOGLOSSIDtE or albulidh:). 
Genus PLETHODUS, Dixon. 
[Geol. Sussex, 1850, p. 366.] 
An imperfectly known genus, with deep laterally compressed 
skuU and small mouth. External bones not ornamented. Pre¬ 
maxilla apparently fused with the short rostrum, this, the maxilla, 
and dentary bearing minute teeth ; ectopterygoid very slender, also 
with minute teeth; a large smooth concave plate, consisting of 
vertical tubules of dentine fixed apparently to the parasphenoid ; 
