XVlll INTRODUCTION. 
the mackerel family, including the tunny, bonito, and sword- 
fish ; the pilot fish ; the dolphin of the Mediterranean, so celebrated 
for the beauty of its dying tints, and the celebrated John dory. 
Among the Malacopterygii Abdominales, or soft-finned fishes, that 
have their ventral fins suspended from the abdomen, the most inte- 
resting are the carp family, the pike family, the flying fish of the 
ocean, the salmon family, and the herring family, including the sprat, 
pilchard, and anchovy. 
The Malacopterygii Sub-brae hiati are soft-finned fishes, with the 
ventral fins beneath the pectorals ; the principal of which are the 
cod family, including the haddock, whiting, and ling ; the flat-fish 
family, including soles, turbots, plaice, and flounders ; and the suck- 
ers or lump-fish. 
The Malacopterygii Apode are confined to the eel family. 
The Lopobranchii include the pipe-fish and other fishes of simi- 
lar form. 
The Plectoffnothii comprise the very singular forms of the balloon- 
fish, and sun-fish. 
The Chondropterygii or Cartilaginous fishes, are divided into 
only three order s,viz., the Sturiones, or sturgeon family ; the Selachi, 
or sharks and rays, including the torpedo ; and the Cyclostomi, or 
lamprey family. 
THE MOLLUSCOUS ANIMALS 
Have no bones except their shells. Their sense of feeling appears 
to be very acute, but the organs for the other senses are either 
wanting or very imperfect. The blood is cold and white, and the 
heart often consists of only one ventricle ; a few of them have im- 
perfect lungs, but the greater number breathe through gills. They 
have all the power of remaining a long time in a state of rest, and 
their movements are either slow or violently laborious. Some of 
them appear incapable of locomotion. They produce their young 
from eggs, but some lay their eggs on a part of their own body, 
where the young are hatched. The following are Cuvier's six 
classes : 
1. Cephalopoda, or Head-footed Mollusca. These animals are fur- 
nished with long fleshy arms or feet, proceeding from the 
head, which is distinct. There is only one order, which in- 
cludes the cuttle-fish, nautilus, and belemnites. 
2. Pleropoda or Wing-footed Mollusca. These animals have two 
membranous feet or arms proceeding from the neck. There 
is only one order, which contains six genera, the best known 
of which, is hyalsea, the shell of which is commonly called 
Venus's chariot. 
3. Gasteropoda or Body-footed Mollusca. All these animals crawl 
with the flat part of the body, which acts as a kind of sucker, 
