51 
e Part V. 
On the Sabet Cranial Bones, a and 
sed Ear-bones of Ctenodu 
By a J. Barxas, M.R.C.S.E., L.R.C.P.L. 
[Read before the Royal Society of N.S.W., 6 June, 1877.) 
Leavrne the bones that enter into the formation ef that portion 
of the buccal Tose connected with the teeth, we come next to 
a 
the endo-skeleton not in our possession were cartilaginous, and 
therefore me ge of foasilination. among the latter are the 
vertebre. ot any vertebral segments have been connected 
poner sa! with Ctenodus, in this respect Cfenodus seemingly 
ing with Ceratodus, the vertebree of which are cartilaginous. 
‘ Tf this fossil fish had possessed a bony spine we should certamly 
have discovered numbers of the segments, both in conjunction 
with undoubted bones of Cfenodus and either single or in masses, 
for other portions of the osseous system are comparatively 
a sue 
Rhicodopecs Megalichthys, Strepsodus, Clacaithes, Archichthys, 
all of which are found in the same coal shales, Looe osseous 
vertebra, aiid which having become prese rved i shale, are 
now obtained just as frequently as any other bones of hides fishes. 
is absence of osseous vertebral segments in Cfenodus and 
Ceratodus at once removes these fishes from the Ctenodipterines 
a sites eo Bis gaa may still pertain to that group, as its 
vert 
The sphenoid or or biiead bone occupies the ete in the base of 
the cranium caused by the otra of the pterygo-pilatine 
bones as they eons om the symphysis. Judging 
posterio: 
. from the great length of the ae I so aati it must have pro- 
"jected much beyond the floor of the c um proper, much further 
than this bone does in Dipterus or even in Ceratodus, in which it 
reaches — back as the third neural pe In the case of 
Ctenodus the posterior projection is very produced, much 
more so ee nt in Ceratodus, while in Diplo exten extends very little 
