104 
ACTINOPTEEYGII. 
Ichthyodectes tenmdens, sp. nov. 
[Plate IX. fig. 6.] 
Type. Imperfect skull; British Museum. 
A small species known only by remains of the head. Oral 
border of maxilla and dentary nearly straight; depth of dentary at 
symphysis not exceeding one quarter the total length of the man¬ 
dibular ramus. Teeth very slender and smooth, with apex slightly 
curved inwards. 
Form. Log. Turonian and (?) Albiau : Kent. 
49054. Type specimen, an imperfect head shown of the natural 
size in PI. IX. fig. 6 ; Lower Chalk, Burham, Kent. The 
fossil exhibits the superior and right lateral aspects of 
the head, but is transversely fractured and partially dis¬ 
placed at the front border of the orbit. The cranial roof 
is narrow, exhibiting the usual median crest behind, and 
the frontal bone of the right side raised into a longi¬ 
tudinal ridge. The frontals seem to extend backwards as 
far as the hinder border of the orbit, and the very small 
median ethmoid is conspicuous at the end of the snout. 
None of the bones are externally ornamented. The ver}’ 
large size of the eye is indicated by fragments of the 
ossified sclerotic {scl .); immediately behind this are the 
remains of the thin cheek-plates (5.0.), with traces of the 
slime-canal which seems to have had radiating branches ; 
while in front may be observed the robust prefrontal 
(ptr.f.), with its flattened inferior facette for the palatine. 
The maxilla (mau) is long and slender, but much fractured, 
so that its anterior end is displaced and only three of the 
slender teeth remain ; a facette postero-superiorly shows 
the extent of overlap of a supramaxillary bone. The 
general proportions of the mandible are indicated, but 
the anterior end of this is also fractured. At the sym¬ 
physis and behind the fracture a few of the characteristic 
teeth are preserved. The outer surface of the dentaiy (d.) 
3s smooth and only gently undulating, without any sharp 
longitudinal ridge. The preoperculum {p).op.) is shown 
to be much expanded, with thickened anterior margin, 
and the usual radiating branches of the sensory canal. 
Mrs. Smith’s Coll. 
41693. Pragment of jaw; Lower Chalk, Hailing, Kent. 
Toulmin Smith Coll. 
47227. Imperfect right dentary; Gault, Folkestone. Gardner Coll. 
