Page:Natural History, Fishes.djvu/323

Rh

In this genus, belonging to the fourth of the above Sub-families, we find spiracles on the temples distinct, though small. There is an anal fin, as well as two dorsals; the first dorsal placed opposite or behind the ventrals, the second behind the anal: the head is short, and the muzzle rounded; the nostrils, pierced near the mouth, are continued by a fissure in the upper lip, forming valves. The teeth are small and acute, with a small point on each side of the principal lobe. The caudal is lengthened, oblique, irregularly lobed, and truncate (or apparently cut short) at the tip.

The names of Dog, Hound, Beagle, and such like, commonly applied to the common Sharks of this and other similar genera, are believed to have reference to their habit of following their prey in packs. They may have allusion also to the prevalent style of colouring in these fishes; spots of varying size, of black, brown, or liver-colour profusely scattered over a light ground, often clouded with brown and yellow.

Like the rest of the Family the Dog-fishes are ground feeders; a habit indicated by the position of the mouth beneath the projecting snout. This habit is not at variance with the fact that several species, such as the Basking, the White, and the Blue Sharks, frequent the warm surface of the sea, at certain seasons, as this has reference to other requirements in their economy.

We have two British species of this genus, of which the Large-spotted Dog, or Bounce