WELLBURX : OX THE GENUS MEGALICHTHYS, AGASSIZ. 57 
from its tip and posterior border, but none are shown on the 
anterior margin. I don't take this as proving that they were 
absent from the anterior border, as they might easily have been 
missed owing to the direction of the section, and it is highly 
probable, considering that the dermal rays not only spring from 
the tip and posterior border, but also from at least the distal 
portion of the anterior border of the fin lobe, that there 
were short radials on the anterior margin of the axial support 
distally ; and considering the fact that the dermal rays, springing 
from this portion of the lobe, are much stronger and more robust 
than the others, it is very probable that their supporting ossicles 
were, although short, strong and robust, and from the above the 
conclusion seems to be that the skeleton of this fin was of a 
nature similar to that shown in Fig. E, PL XVII. 
The dermal fin rays are similar to those of the pectoral fin 
in character and arrangement. 
The pelvis is probably represented by an elongated cartila- 
ginous element, covered with a layer of dense bone and having 
the distal end concavo-truncate (see Cope, op. cit., p. 458). 
In the Leeds fish, between these fins are three large, elon- 
gated scales, one median and tw^o lateral, which may be called 
"pelvic scales." On the left side of the median one the anus 
is well shown. The anus is not always in this position as is 
shown by other specimens. The difference is probably connected 
with the sex of the fish. (PI. XIY., LPS and MP S, also 
PI. XIIL, P S.) 
Unpaired fins. — There are two dorsal fins situated far back, 
the first being opposed to the ventral and the second to the anal 
fin, which arises close to the root of the tail. All the fins are 
lobate, the lobe being more acute than that of the paired fins. 
Anal fin. — The superficial characters are well shown in several 
specimens, viz., in the Leeds fish, in the specimen in the Science 
and Art Museum, Edinburgh, described by Dr. Traquair (Proc. 
Roy. Phys. Soc. Edinb., Yol. YIIL, p. 67), and in a specimen 
in the Lister Collection, Brighouse, ko,. (PI. XIY., A F, and 
PI. XYL, A F). 
