SoyMNIDffl. FISHES. PETKOMYZONTlD.ffii. CClv 
species (M. vulgaris),” says Mr. Yarrell, “ is the most 
common of all tlje Sharks. It is afiSrmed that, on 
the coast of Oornwall, as many as 20,000 have been 
taken in a net at one time. This Fish bends itself 
into the form of a bow for the purpose of using its 
spines, and, by a sudden motion, causes them to 
spring asunder in opposite directions; and so ac- 
curately is this intention effected that, if a finger be 
placed on its head, it will strike it without piercing 
its own skin. This Fish is subject to occasional 
monstrosity. A friend has one with two heads, the 
separation continuing as far back as the pectorals.” 
Belon figures Ghien de Mer, which is a tolerably 
good illustration of the Dog-fish. He also figures two 
species of Galeus. One other he calls Oaleus hin- 
nulus, or Nissole, a species of Ghien de Mer ; and 
yet another form he names Acanthus, or Spinax. 
ilondelet records, with crude wood-cuts, Milandre — 
Galeus canis of Fliny, Lamiola of the Romans. An- 
other he names Ghien de Mer estelle, or in Greek, 
Asterias galeus. Galeus glaucus, or Ghien de Mer 
Men, resembles the Lamna of our waters. Excellent 
figures of the egg-cases are given by Rondelet. 
PICKED DOG-FISH (Squalus americanus (Storer), 
Gill). — Called, also, Bonk-dog, Skittle-dog, and Hoe 
in Great Britain. It ranges from Newfoundland to 
Cape Hatteras. Storer and DeKay record this Fish 
as Spinax acanthias, and the former, later, as Acan- 
thias americanus. it measures from one to three 
feet long, and is caught in immense numbers in 
Massachusetts Bay, in the spring and autumn, for the 
Sake of its oil, which is used by tanners and curriers. 
A species, found in Greenland waters, is named Cen- 
trocyllium fabrici (Reinh.), Muller and Henle. 
Family— S GYM NJDiB. 
Scymnus is the name of the typical genus, and gives 
name to the family. The characters are seen in the 
absence of the anal fin and the round dorsals. 'I'here 
are two dorsal fins, the first situated in advance of 
the ventrals, the second far behind. 'J’he family em- 
braces genera Scymnus, Somniosus, and three others 
found in the Mediterranean Sea. 
NURSE ; SLEEPER {Somniosus microcephalus 
{Bloch), Gill). — Found from the Polar regions to 
Cape God. DeKay described this species as Scym- 
nus brevipinna, and remarks that Leseur described it 
Irom a stuffed specimen he saw in Marblehead. It 
has been regarded as very rare, and Dr. Storer re- 
cords some instances of its capture on the New 
England coast, one in 1846, and again in 1848, and 
he adds: “I have learned, from conversation with 
intelligent fishermen, that individuals are captured 
every winter.” It is sometimes seen to measure 
iwenty feet in length. At Gape God it is called 
Gurry or Ground Shark. About the year 1843 
the author examined a specimen brought ashore at 
Swampscott Beach, of which he took accurate 
measurements and drawings. These he presented to 
Prof. Agassiz of Gambridge, who, at that time, had 
not seen the species in our waters. Gill records it as 
doubtful as to species. 
Family— PE I’ROMYZONTID^. 
From two Greek words, meaning stone, and to 
such; hence. Stone-suckers. 'Phis family comprises 
all of the order Hyperoartii. 'I'he form is eel-like ; 
the skin naked; eyes well developed ; mouth with a 
subcircular, suctorial disk, armed with teeth which 
are horny, and sessile on soft papillm. 'I’he branchial 
apertures are always seven in number, and lateral. 
'I'he dorsal, anal and caudal fins are represented to a 
greater or less extent by a continuous or interrupted 
membrane ; the pectorals and ventrals not developed. 
'I’he intestine has a spiral valve. 'I’liese are the 
characters of the adults, but all undergo a meta- 
morpihosis ; and a very different form is seen in the 
young or larvie. 'J’he term Ammocoetes was formerly 
used to distinguish these immature forms, under the 
impression that they were adult beings. In this 
larval state, the region before the branchiai is little 
developed, and the eyes are absent ; the mouth is 
represented by a mere longitudinal slit, without 
teeth. 'J’he species are represented in temperate 
portions of both northern and southern hemispheres, 
in a degree the species are parasitic, fastening them- 
selves to other Fishes, whose flesh they consume by 
abrasion — differing in this respect from the Echeneis 
or Remora, which simply adhere for companionship. 
See, also, vol. ii., p. Ill, and Plate 1, fig. 2. 
LAMPREY ; LAMFER-EEL {Petromyzon america- 
nus, Leseur). — Ranges from Gape God to Hatteras. 
Gill records this as doubtful as regards the identi- 
fication of species. Mitchill described it as the same 
as the Jlluropean species ( P. marinus). Storer remarks 
that it is occasionally taken in Massachusetts Bay, 
attached to pieces of drift-wood and the bottoms of 
boats and larger vessels. In the Merrimack River, at 
Lowell, they are taken in large quantities. During 
the spawning season they ascend the rivers a little 
earlier than the Shad, moving mostly in the night. 
Not being seen to return, the fishermen imagine 
they die. During summer they are often seen in 
pairs, at work together, constructing a mound, about 
three feet in diameter at the base and two feet high, 
composed of stones from the size of an ounce bullet 
to that of the Fish. DeKay describes it as “ 'J’he 
American Sea Lamprey, thirty inches long, and very 
different in its dentition from P. marinus of Europe. 
'I’he Sea Lamprey is commonly taken in our bays and 
salt-water streams about the month of April, and, 
judging by the prices at which they are sold, must 
be held in high estimation by epicures. 1 have ob- 
served them at Albany in the spring, and was assured 
that they were taken a few miles below that city.” 
BLACK LAMPREY {Ammocoetes nigricans {Leseur), 
Gill). — Ranges from Gape God to Hatteras. Gill 
has it doubtful as to sjiecies. DeKay records it as 
Bluish Sea Lamprey (Petromyzon). Storer says it 
is frequently attached to Mackerel and other Fishes. 
THE SMALL LAMPREY {A. appendix {DeKay), 
Gill) has a similar range, and is also doubtful as 
to species. DeKay first obtained it from Provi- 
dence, R. 1., and afterwards from the Hudson River. 
A. bicolor, Leseur, is another species. 
