PROF. L. C. MIALL ON A MEGALICHTHYS. ara) | 
Between the ventral fins are three large scales, one median and 
two lateral, which may be called the pelvic scales (fig. 4 p, p', p’). 
‘On the left side of the median scale and of the middle line of the 
body lies what I take to be the anus, distended with fossil feces. 
It is quite plain that the anus does not lie immediately in front of 
the anal fin, as in Lepidosteus and other recent Ganoids, but is 
associated with the pelvis and ventral fins in a manner not uncommon 
with Teleostei ; in some of which, indeed, the anus follows the 
ventral fins, even when they are shifted to a thoracie or jugular 
position. 
The anal fin has also its pair of large basal scales (fig. 6 6,6). Of 
the caudai fin but little can be made out, and it is uncertain 
Fig. 6.— Anal fin of Megalichthys Hibberti, the very convex surface 
represented as plane. (One half natural size.) 
b, 6b. Basal scales. 
whether, as in Osteolepis and Diploptcrus, fin-rays proceeded from 
the upper as well as from the lower surface*. 
There are indications of the underlying skeleton behind the skull 
and in the neighbourhood of the paired fins; what seems to be the 
* Since this paper was sent in, Dr. Traquair has described and figured the 
tail of Megalichthys (Proc. R. Phys. Soc. Edin. vol. viii., and Geol. Mag. March, 
1884). It “may be said to be somewhat intermediate between the diphycercal 
and heterocercal types; at least it is not quite so heterocercal as that of Osteo- 
lepis, and in general form reminds us of that of Tristichopterus. Rays arise 
from both the upper and lower margins of the body-continuation, but those of 
the lower side commence in adyance of those of the upper.” 
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