THE MUSEUM 
OP 
NATURAL HISTORY. 
ZOOLOGY. 
CLASS IV. 
“ Forthwith the sounds and seas, each creek and bay 
With fry innumerable swarm, and shoals 
Of fish that with their fins and shining scales 
Glide under the green wave, in sculls * that oft 
Bank the mid-sea : part single, or with mate 
Graze the sea-weed their pasture, and through groves 
Of coral stray, or sporting with quick glance 
Show to the sun their wav’d coats dropt with gold, 
Or in their pearly shells at ease attend 
Moist nutriment, or under rocks their food 
In jointed armour watch.” 
— Milton's Paradise Lost, vii. 399. 
Fishes rank in the scale of animated beings as the 
lowest division of V ertebrals. In the preceding pages 
of this work, the reader has been informed how the 
massive bony frame-work and other parts of the 
mammalian structure are modified in the instances of 
Seals and Cetaceans, to adapt an air-breathing vertebral 
for an aquatic life; and also how the Penguins are 
able to live the life of a fish, through peculiarities of 
their ornithic constitutions. These and similar facts 
afford us glimpses of the inexhaustible and admirable 
methods by which the great Creator has constructed 
animals for the performance of their special functions, 
yet without effacing the structural type of the particular 
class to which they belong. The discovery and just 
appreciation of such instances of creative wisdom, are 
delightful rewards of zoological study. By the contem- 
plation of the creatures to which our attention is now 
to be directed, we perceive, at the outset, that the 
ponderous bones of terrestrial quadrupeds, or even 
the much lighter yet firmly knit skeletons of air- 
cleaving birds, are not essential for animals breath- 
ing and moving in a medium nearly as heavy as 
their bodies, which receive no shock in cleaving a 
way through it with the rapidity of an arrow. The 
nature of the medium in which they dwell not only 
allows great variety in the density of the skeletons of 
fishes, but also a diversity of external form surpassing 
anything that has been noticed among the higher 
groups of Vertebrals, whose aggregate numbers are, 
in fact, very inferior to those of the finny tribes, 
• Aiie:lo-Saxon sceote, an assembly. 
—FISHES. 
whether we look to species or individuals. Some 
fishes have little or no bony matter in their bodies, 
and one small fish, occupying the lowest place in the 
ichthyic scale, is actually destitute of the head and 
brain, so characteristic of the more highly organized 
members of the division. 
Using the term Fishes in the broadest sense in 
which it is employed by naturalists of the present time, 
to denote a group of vertebrals living habitually in 
water, and respiring that fluid during the whole course 
of their life, and not merely temporarily, like the 
Amphibians, our purpose is to present such a view of 
the whole group as may be useful to the student of 
ichthyology, without overpassing the limits assigned 
to the subject by the projectors of “ The Museum.” 
The Natural History of two orders of osseous fishes 
only, written by Cuvier and Valenciennes, extends to 
twenty-two thick octavo volumes ; * the work of 
Muller and Henle on the Sharks and Rays, exceeds 
two hundred pages folio ; f and the admirable lectures 
of Professor Owen on the Anatomy of Fishes, fill three 
hundred pages of small type. J The space allowed to 
the class in this work will not suffice for more than 
an attempt to present the characters of the Orders 
and principal Families, with brief notices of some of 
the fisheries ; and to add a very few facts evincing 
intelligence or natural affection in some members of 
the Class. 
The marine abodes of fish, secluded from continuous 
observation, limit our knowledge of their habits ; and 
some kinds that are objects of important and costly 
fisheries, are known only in that epoch of their exist- 
ence in which they approach the shores for the 
purpose of spawning. Several large species residing 
habitually in deep waters, and coming to the surface 
under the accidental circumstances merely of injury or 
disease, have been captured at rare intervals, by seamen 
* Histoire Naturelle des Poissons, par M. Le Baron Cuvier 
et M. A. Valenciennes An. 1828-1849. Tom. xxii. A Paris. 
f Beschreibung der Plagiostomen, von Dr. J. Muller and 
Dr. J. Henle, 1841. Berlin (60 plates). 
I Lectures on Comp. Anatomy of Vertebrate Animals, by 
Eichard Owen, F.E.S., 1846. London. 
