398 
ACTINOPTERYGII. 
specimen, are preserved on each side, though somewhat 
fractured, as shown in fig. 5 ; and part of the supra- 
maxillary plate (fig. 5, s.mx.) is also exhibited overlapping 
the hinder end of the maxilla. The anterior end of the 
alveolar border of the dentary bone of the mandible 
(fig. 5, cl.) appears sinuous in side view, and the most 
anterior teeth, which are enlarged, are directed slightly 
forwards. Within the mouth remains of the pterygo¬ 
palatine arcade are observed above (fig. 5,pt.), but it is not 
possible to distinguish the elements ; on its inner face 
there is a crowd of minute denticles (probably entoptery- 
goid) which gradually become a little enlarged below, while 
on the oral margin (probably ectopterygoid and palatine) 
there are large teeth irregularly arranged and spaced, the 
largest being near the anterior end. When viewed from 
within, the dentary exhibits the usual thickened alveolar 
border, this in its hinder portion roofing the space occu¬ 
pied by the meckelian cartilage. The splenial element is 
also conspicuous, and may consist of more than one portion. 
As shown in a fragment from the left side a thickened, 
lenticular portion of this element (fig. 5 a, spl.) enters 
the mandibular symphysis, and bears at least one large 
tooth immediately behind the enlarged, forwardly pointing 
teeth of the anterior end of the dentary. Posteriorly on 
the inner face of the left mandibular ramus a thin laminar 
bone (fig. 5, spl. ?), bearing minute granular teeth, is 
crushed upon the dentary in such a way as to suggest its 
forming the inner wall of the cavity for the meckelian 
cartilage. Another specimen still in Mr. Leeds’ private 
collection exhibits the same plate continued forwards 
above in a long slender process ; it is thus probably to be 
identified as a hinder splenial. There is nothing worthy 
of remark in the remains of the pectoral arch, but one of 
the pectoral fins (fig. 6) is interesting. The three fore¬ 
most rays, successively increasing in length, are fused 
together, and their thickened proximal end (fig. 6 a) 
exhibits a hollowed, circular, articular facette (/.). The 
other rays are closely adpressed and unjointed so far as 
preserved, while their proximal ends simply clasp the 
basal cartilages. A few very fine tubercles ornament the 
sharp anterior border of the fin, and similar tubercles are 
observed on parts of the other rays. Among fragments 
