428 
VERTEBEATA. 
Genus SPIN AX : Spinax. — This includes tlie Picked Dog-Fish, S. acantkias, one to three 
feet long ; as it is exceedingly voracious, and the species numerous, it is one of the principal 
scavengers of the seas. It is called Spinous Dog-Fish by De Kay. Found on both sides of 
the Atlantic. 
Genus SCYMNIJS : Scymnus. — To this belongs the Greenland Shark, aS'. horealis, fifteen 
to twenty feet long, six to eight feet in circumference ; the mouth large, the color ashy-gray. It 
is a great enemy to the whale, biting lumps as big as a man's head out of its body even while 
living. It gorges itself upon such whales as it finds dead ; it does not appear to attack mankind. 
Its heart is small, beats about six times in a minute, and pulsates for some hours after being taken 
out of the body. It is unsafe to put the hand into its mouth, even after the head is severed from 
the trunk. Its insensibility to pain is such that a knife may be run through its body and the 
animal will still go on gorging itself with food. Besides the flesh of whales, it devours various 
kinds of fish. It is infested with parasitic insects — a species of Lerncea — some of which are 
three inches long. It is found in the North Atlantic. 
The Nurse, S. brevipinna, is six to seven feet long, and sometimes called Sleeper, from its 
sluggish habits. Found on the coasts of Massachusetts. 
Geyius ZYG^NA : Zygcena. — To this belongs the Hammer-head Shark, Z. malleus, having 
a body like other sharks, but with 
a double snout like a double-headed 
hammer, and having an eye in the 
middle of each extremity ; it is 
very voracious, and from twelve 
HAMMER-HEAD SHARK. 
to twenty-five feet long. One of 
them taken on the coast of Long 
Island had parts of the body of a 
man and his clothing, in his stom- 
ach. This species is found on 
both sides of the Atlantic. 
Genus SQUATINA : Squatina. — To this belongs the Angel Fish, aS'. angelus, which seems to 
partake of the nature of both sharks and rays. Notwithstanding its name it is a hideous-looking 
^ creature, with two enormous pec- 
toral fins, said to have given it its 
name, from a fancied resemblance 
to the wings of angels. It is three 
to four feet long, and in Europe 
goes under the various titles of 
MonJc-Fish, Monkey-Fish, SharJc- 
Ray, and Fiddle-Fish. Found on 
both sides of the Atlantic. 
Genus PRISTIS : Pristis.—To 
this belongs the Saw-Fish, P.an- 
tiquorum, fifteen feet long, having 
a body like the shark, but the 
snout being extended like the 
blade of a sword, with strong and trenchant teeth on both sides. This powerful weapon is 
sometimes five or six feet long, and with it these fishes often attack whales and inflict dreadful 
wounds. 
THE RAHD^. 
These animals are of a flat or depressed figure, the great breadth of the body being produced 
by the singular expansion of the pectoral fins. There is no distinct head ; the tail is long and 
slender, and furnished with two dorsal or upper fins, and sometimes with the vestige of a caudal 
fin. The mouth and branchial orifices are on the under surface. The texture of the skin varies ; 
THE ANGEL FISH. 
