ccxxiv Introduction. FISHES. Structure. 
water must be pure, and well-charged with oxygen, 
tliat tlie delicate vessels which ramify through the 
gills may readily absorb the life-giving pabulum. 
There are, however, Fishes that seem rather to inhabit 
the mud' and sands at the bottom of tlie water, as, 
for example, the Flat-fishes — Flounders, Sole, Plaice, 
etc. 'J’he Silurus fossilis is so called because it is 
not seen excepting when actually dug out of tlie 
mud. 'I’hese are not, however, wholly removed from 
the influence of the water above them. There are 
Fishes that are capable of leaving the water entii-ely. 
roaming abroad, and temporarily abiding on the 
earth. p]els frequently crawl along the slimy grass, 
during the night, from one jiiece of water to another. 
The Soldier ioricaria, found in Surinam, is described 
as not only passing over land, but actually burrow- 
ing to find water more acceptable. 'I'he most aston- 
ishing feat is performed by the Climbing Perch 
(Anabes scandens), a native of Asia, which actually 
passes over dry and high banks in its search forjiools 
of deepei- water. These Perch are known to live five 
or six days out of water, and it is noticed that the 
gills are expanded during the time they are thus ex- 
posed. The structure of the pharyngeal bones in 
this species is so modified as to present support for 
certain labyrinthine cells, which retain a small quan- 
tity of water, sufficient to moisten the gills. It may 
be noted that the most remarkable deviation from 
the normal life and habits of this class is seen in the 
small group of Flying-fishes, some of which are able 
to maintain a continuous flight for a few seconds ; 
but their strictly fish-nature requires that they return 
to breathe beneath the waters. 
Fishes are nearly of the same specific gravity as 
water, consequently they move with great ease, in all 
directions. The usual mode of progression is by the 
strong muscular tail, the action of which is imitated 
in “sculling” a boat. Other fins are but little used, 
except for balancing. Among the singular analogies 
met with in Fishes is that of the possession of a pouch, 
formed of two soft flaps, seen in the Pipe-fishes and 
Sea-horses. Here is a marsupial fish ! although in 
these instances the male possesses the marsupiuni. 
'I'he genus Aspredo, of the Siluridm, exhibits the 
strange condition of hemispherical depressions in the 
belly of the male, wit.hin which the eggs are deposited, 
not unlike those of the Surinam Toad. Some species 
of Pi])e-fish are credited with this habit. Well au- 
thenticated instances of nest building are known, as 
in the case of the familiar Stickleback. 'I’lie won- 
derful change of color that certain Fishes undergo is 
not satisfactorily accounted for. Mr. Farrell ascribes 
it to the effect of mental agitation. 'I'he Stickleback 
is a notable instance of this apparent “emotion,” 
and is particularly subject to radical changes of color. 
Great changes are noticed in the colors of the same 
species in different localities, and in no class of the An- 
imal Kingdom are there more instances of the power 
of simulating the colors of their surroundings. 'I’he 
remarkalile work of M. Sauvigii}' exhibits no less 
than eighty-nine different varieties of the Golden 
Carp, including the richest colors, both uniform in 
tint and parti-colored in the most grotesque manner. 
Besides the immense commercial importance of a 
large number of species of Fishes, there are various 
products which serve more or less valuable purposes. 
'I’he early writer, Belon, describes the use of the 
“ear-bones” as proving “infallible in certain com- 
plaints.” Shagreen is an article derived from some 
species of Sharks and Rays. Pliny mentions that 
the Romans were in the habit of using this substance 
for polishing ivory and wood. 'I’he rough skin of the 
Rays forms a very beautiful and useful shagreen, 
which is used in covering scabbards and surgical in- 
struments. 'I'he isinglass of commerce is derived 
from a species of Sturgeon ; and a kind of glue is 
made from the common Cod. Edible Fishes are ex- 
ceedingly numerous on the coast of North America. 
One hundred and seventy species are described as 
known in the New York market. 
'I’he early literature of Ichthyology presents some 
exceedingly crude though interesting ideas, that 
were entertained by the ancients. 'I'hrough the lib- 
erality of its president, the American Museum of 
Natural History, in New York, is now in possession 
of the large and most valuable Ichtliyological Li- 
brary which was collected by J. Carson Brevoort, 
Esq. 'riiis unusual source of information we have 
fully consulted, and have endeavored to present 
herein as much of the matter, dating from the earli- 
est to the present time, as will contribute something 
like a complete history Ichthyology in outline. 'I’he 
name of Hippolyti Salviani stands clearly prominent, 
not only as the first reliable author, but as one that 
is most honorably connected with one of the best- 
illustrated works, either of modern or ancient times. 
Salviani was born in Italy, A.D., 1514, of noble par- 
entage ; was Professor of Medicine in the University 
of Rome and physician to Pojie Julius III. In these 
early times, when nothing had been done in Compar- 
ative Anatomy, this writer commenced the examina- 
tion of the interior of his subjects. His work is a 
folio volume of 500 pages, published in a very stylish 
manner, the general execution of which is not sur- 
passed at the present day. A laige full-page cop- 
per-plate portrait of its author, with exceedingly fine 
accessory portions, including arms, etc., bears the 
following title: Aquitalium Animalium Ilistorice, 
Romcc, mdliiii. Then I’ollow tables and chapters, 
which have an aspect of more system than the mis- 
cellaneous collections of fabulous and truthful matter 
seen in previous authors. 'I’here are about one hun- 
dred copper-plate engravings, which, to use tlie lan- 
guage of Sir William Jardine, who has copied largely 
from the work, “have not been surpassed for fidelity 
and beauty in modern times.” Certainly nothing 
has yet appeared to excel ’in beauty and artistic 
accuracy these large copper-plate engravings. 'I’he 
work of Conradi Gesneri, Ilutorim Naturalium, etc., 
1558, is a large folio, with numerous wood-cuts, many 
of them well drawn, but coarsely executed. 'I’he 
works of Oppian and Pliny are but little more than 
records of fanciful stories of animals, many derived 
from Aristotle. From these we have extracted some 
interesting accounts relating to species well known 
from the earliest times, and equally known in the 
