PROCEEDINGS OF THE SOCIETY. 135 
and fins, lighter on the sides, and white below; skin a little 
rough when rubbed against the grain. The male was smaller 
than the female by fully 12 to 15 inches. The sex was clearly 
and very readily made out by the distinctive characters of the 
anal or pelvic fin. In the female this fin is square-shaped and 
without any appendages; from a point above, which may be 
termed the mons veneris, to the lower edge of the double fin, the 
length is nearly 10 inches; breadth of lower border 7} inches ; 
on the inner side of the two equal divisions of the anal fin, at a 
_ point about 2 inches above the margin, there is felt to be a slight 
bony prominence, which has a distinct relation to a jointed spine 
in each clasper fin in the male. The anal fin of the male is much 
smaller than that of the female, but at a point where the fin 
proper terminates there is a strong bony appendage with a joint 
admitting considerable lateral motion. This appendage (which 
may be described as an accessory copulatory organ) is fully 10 
inches in length, and about 44 inches in circumference at its 
rounded part; one side is entirely smooth down to its tapering 
point, but on its other surface are grooves and spaces which are 
more marked towards the joint than at the base ; about 24 to 3 
inches from the tip there is a joint of an ordinary hinge character, 
and, when this joint is somewhat flexed, there is projected from 
a joint within the fold a sharp-pointed spinous process which lies 
horizontal to the line of the clasper appendage, its function 
_ evidently being for purposes of clasping. 
The snout of the Porbeagle Shark resembles that of the hog, 
hence the name “hog-hound” by which it is sometimes known. 
It follows its prey by sense of smell as well as by sight. Its 
olfactory nerves are very highly developed, and all over the 
snout, and even beyond the eyes, are numerous little openings 
from which a reddish gelatinous fluid was expressed. The eye is 
a very striking object of vision, and can be projected outwards 
beyond the line of the orbit, thus increasing its range of vision. 
There is a distinct and somewhat broad rim of bone in the 
sclerotic coat, to which powerful muscles are attached. This rim 
of bone seems to serve also as a protecting shutter against 
_ obstacles when the fish is running at a high rate of speed. By 
_ some naturalists the Porbeagle is said to have no spiracles. A 
_ small wire was passed into a minute and easily overlooked open- 
