A NEJV CBETACEOUS FISH. 
9 ?- 
There is also an abraded plate in the post-orbital region, filling the space between the- 
anterior branch of the hyoraandibular and the lower siib-orbita.! plate. 
Ganoine . — There is a distinct film of ganoine on most of the bones of the cranial 
roof, and there are small patches remaining on the other external cheek-bones, showing 
that these were enamelled. Where the ganoine is well preserved it gives a shining 
brown appearance to the fosvsil, and here and there are small patches with a bluish 
or opalescent tint similar to that on the large scales of onr specimens of Belonosiomtis ^ 
(Ganoine is here used for a layer of successive lamellai of enamel-like, cell-less 
substance,” as defined by E. S. Goodrich (1909, p. 218).) 
H't/ornandibular . — The vertical head, articulating with the pterotic region, is 
somewhat massive, and is much larger than the anterior head, which projects forwards 
to the sphenotic, some 50 mm. from tlie median line of the bone. The abraded outline 
of the bone is well marked on Plate X, and it will be seen that there is a more slender 
branch passing posteriorly to the operculum. Below the anterior and posterior 
branches, the lengthy median portion of the hyomandibular extends to the sym])lectic, 
and this portion forms almost a right angle to the series of vertebriic. Although this 
left-hand bone is much abraded, a displaced fragment of the right (component, exposed 
from deep matrix, shows that the lateral surfaces of this large and complex bone were 
prominently flanged on the axes of the branches and that a thin plate of bone extended 
between the anterior and vertical heads. 
Opercular The posterior margin of the operculum is incomplete, but 
there is no evidence of radial furrows or striations or of a serrated border. The portion 
preserved is an extensive plate, considerably deeper than wide. There is an oblique 
suture between it and the suboperculum, which is very incomplete, but this and the 
interoperculum, represented by .fragments, were evidently extensive plates. Only a 
small portion of the anterior j3late of the preoperculum is preserved, and this abuts 
on the median })art of the hyomandibular. The exposed area betw^een the hyoniandi- 
bular and the operculum is now filled with wliite matrix and disrupted l)ones. 
Gular Plate. — Betw’een the mandibular rami in their anterior half is an extensive 
tongue of bone, which represchits a gular ])late. (Plate XI, figure 2.) This element 
was evidently paired, but owing to the displacement of the rami the area 
is somewhat obscure. The gular plate projects from the infero-lateral surfaces of the 
mandible and extends for about half the length of the rami, but it is much less robust 
posteriorly. In the anterior part of tlie symifiiyseal region there is evidence of a 
tumid extension of the mandible, which is now' much abraded. 
Bro-ncJhiosiegals . — Below' the j)osterior third of the mandibles are the disrupted 
remains of large branchiostegal rays, and there are fragments of at least eight large 
rays present on each side. Behind these and below the quadrate there is a compressed 
cylindrical bone, which apparently represents the cerato-hj^al and epihyal, w'ith a well- 
marked suture betw'een the tw'o. 
Pectoral Girdle . — The remains of the pectoral girdle form an extensive curved 
plate, about 50 mm. behind the opercular apparatus (Plate X). Unfortunately the 
