198 The True Sharks 
below. The heterocercal tail has no keel; the end is bent up- 
ward; both dorsal fins are present, and the first is well in front 
of the ventral fins; the last gill-opening over the base of the 
pectoral, the head normally formed; these sharks are ovovivipa- 
rous, the young being hatched in a sort of uterus, with or 
without placental attachment. 
Some of these sharks are small, blunt-toothed, and innocuous. 
Others reach a very large size and are Bunpassed in voracity 
only by the various Lamnide. 
The genera Cynias and Mustelus, comprising the soft-mouthed 
or hound-sharks, have the teeth flat and paved, while well- 
developed spiracles are present. These small, harmless sharks 
abound on almost all coasts in warm regions, and are largely 
used as food by those who do not object to the harsh odor of 
Fig. 140.—Soup-fin Shark, Galeus zyopterus (Jordan & Gilbert). Monterey. 
shark’s flesh. The best-known species is Cynias canis of the 
Atlantic. By a regular gradation of intermediate forms, through 
such genera as Rhinotriacis and Triakis with tricuspid teeth, we 
reach the large sharp-toothed members of this family. Galeus (or 
Galeorhinus) includes large sharks having spiracles, no pit at the 
root of the tail, and with large, coarsely serrated teeth. One 
species, the soup-fin shark (Galeus zyopterus), is found on the 
coast of California, where its fins are highly valued by the 
Chinese, selling at from one to two dollars for each set. The 
delicate fin-rays are the part used, these dissolving into a finely 
flavored gelatine. The liver of this and other species is used 
in making a coarse oil, like that taken from the dogfish. Other 
species of Galeus are found in other regions, Galeus galeus being 
known in England as tope, Galeus japonicus abounding in Japan. 
Galeocerdo differs mainly in having a pit at the root of the 
tail. Its species, large, voracious, and tiger-spotted, are found 
