46 
NATURAL HISTORY. £UPPER FLOOR. 
The Gurnards ( Triglce ) are distinguished from the other 
Percoid Fish, by the bones of the face being very large, so 
as to cover the cheeks. Some of these have the pectoral 
fins so large, that the fish can support themselves for some 
time in the air, and are therefore called Flying Gurnards 
( Dactyloptera ). 
Cases 1 and 2. The Scienoid and the Sparoid Fish 
differ from the Perches, in the palate being without teeth. 
Some of these, as the Sargi (a Sargus), have large teeth on 
the side of the jaw (Chrysoplirys and Deuteoc). 
The Maenoid Fish differ from those of the two former 
families, by the jaws being protractile and retractile. 
The Chaetodons are known by their compressed form, 
and by their dorsal, and often their other fins being covered 
with scales like the rest of the body. The teeth are 
usually very small and numerous, resembling bristles, from 
whence the name. The common Chaetodons ( Chcetodon ) 
have their opercular bones finely ciliated, while the horny 
Chaetodons have the lower part of the operculum ending 
in a large spine. These fish are very numerous on the 
rocky shores of the seas of w^arm climates. They are 
generally beautifully and variously coloured, and good for 
food. Many are rejected from prejudice, though the Sea 
Bream ( Brama ) has many of the characters of the Chaeto¬ 
dons, except that the palate is not toothed. 
The Scomberoid Fish have a smooth skin covered with 
a multitude of small scales, and a large caudal fin. They 
are much used as food, and afford great employment to the 
fishermen. 
The Mackrel ( Scomber ) has two dorsal fins : the hinder 
rays of the posterior are separated from each other, form¬ 
ing, as it were, a series of small fins, as in the common Mack¬ 
rel (Scomber scombus). Some of the species have a ridge 
of cartilaginous spines on the side of the tail. 
The Sword Fish (Xiphias) is very like the Tunny, but 
the front part of its upper jaw is produced into a long 
beak, with which it attacks the larger sea animals. It swims 
with excessive rapidity, and its fiesh is much praised. The 
common Sword Fish (Xiphias gladius) has no ventral fins. 
The Flying Sword Fish (Notistiu?n) has distinct ventral fins, 
and the dorsal very high and long, which enables it to swim 
with such velocity that it can drive its beak through the 
