PEOF. L. C. MIALL ON A MEGALICHTHTS.
351
Between the ventral fins are three larjs^e scales, one median and
two lateral, which may be called the pelvic scales (fig. 4 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 anns, distended with fossil faeces.
It is qnite 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 thoracic or jugular
position.
The anal fin has also its pair of large basal scales (fig. 6 h, h). Of
the caudal fin but little can be made out, and it is uncertain
Pig. 6.-
- Anal fin of Megalichthys Hibberti, the very convex surface
represented as plane. (One half natural size.)
.&^
h, h. 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 .^roc.'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 advance of those of the upper."