226 
ACTINOPTEEYGII. 
some of its large teeth; and the two dentary bones (d.) 
of the mandible occur deeper in the matrix, that of the 
right side being partly obscured. The left articulo- 
angular bone (ag.) is displaced, and also partly covered 
by other fragments. The imperfect left operculum (op.) 
is distinguishable from its inner face, but is turned so 
that its horizontal axis is directed downwards. Five of 
the anterior vertebral centra are exhibited, showing the 
deep infero-lateral pits for the ribs. Further back are 
other centra, beneath which the somewhat robust ribs are 
also preserved. There are obscure remains of the 
pectoral arch, with traces of very stout pectoral fin-rays 
(pet.); and there is only a fragment of one other fin, the 
dorsal, which has remarkably robust supports, but is not 
shown in the figure. Five of the characteristic scutes ( 5 .), 
partly displaced, are observed on the ridge of the back in 
front of the dorsal fin, the two foremost being shown 
chiefly as an impression of the outer face. 
Purchased, 1891. 
P. 6339. Scattered remains of head and anterior abdominal region, 
sketched in outline in the accompanying fig. 9. The 
imperfect cranium, wanting the ethmoidal region, is 
exposed from beneath, and the well-preserved basi- 
occipital (h. oec.) demonstrates the absence of a basicranial 
canal. The otic region is shown to be well ossified, and 
bounded in front by a prominent sphenotic or post-frontal 
(sp.o,). Further forwards there are remains of the large 
frontals (fr.). The displaced jaws are observed below 
the overturned cranium. The imperfect right palatine 
(r.pl.) and anterior end of ectopterygoid (r.ecpt.) are 
partly obscured by the fragments of the frontal region. 
Next below is part of one of the thin laminar premaxillae 
(pmx.), bearing the characteristic regular series of small 
recurved teeth. Then follow remains of the left pala¬ 
tine (l.pl.) and ectopterygoid (l.ecpt.), displaying the 
characteristic dentition. The hinder portion of the 
ectopterygoid is toothless, and curves downwards as it 
approaches the quadrate (qu .); while it seems to be 
bounded above by the entopterygoid (l.enjgt.), which 
exhibits the bases of an antero-posteriorly elongated 
cluster of minute teeth. The fragmentary hinder portion 
of the right ectopterygoid (r.ecpt.) partly overlies the left 
