140 
NATURAL HISTORY. 
[n. zool. gal. 
hard, toothed, and striated scales; the base of the tail is marked with 
two prominent keels, the dorsal fin is low, long, and spinose, the lower 
jaw fits into the upper; both are furnished with a single row of small 
teeth. They are found in deep water. 
The family of Chsetodons ( Chjetodonidje) are known by their 
compressed form, and by their dorsal, and often their anal fins being 
covered with scales like the rest of the body. The teeth are very small 
and numerous, resembling bristles, from whence the name. Their 
palate is generally toothed. They are numerous in warm climates, 
beautifully coloured, and their flesh is good food. The common Chse¬ 
todons ( ChcBtodon ) have their opercular bones finely ciliated, while 
the Horned Chsetodons ( Holacanthus) 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 warm climates. They are generally 
beautifully and variously coloured, and good for food. Many are re¬ 
jected from prejudice. 
The family of Pimelepteres (Pimelepterid^:) are very like the 
former in shape and structure, but they have teeth with sharp cutting 
edges. 
The family of Sea Breams (Bramadje) are like the two former fa¬ 
milies in the form and structure of the fins, but they have small velvet¬ 
like teeth in the jaws and palate. 
The family of Scomberoid Fish ( Scqmberoidje) have a smooth skin 
covered with a multitude of small cycloide scales, and a large caudal fin. 
The opercular pieces are unarmed, and their vertical fins are generally 
destitute of scales. They are much used as food, and afford great em¬ 
ployment to the fishermen. They are divided into several groups ac¬ 
cording to the form of the fins, &c. 
The first group have the hinder rays of the dorsal and anal fin sepa¬ 
rated into small fins, and the lateral line unarmed. The Mackarel 
( Scomber ) has two ridges on each side of the tail, two dorsals, and equal 
sized scales. The Auxides , Thynnus , and Pelamus have a single ridge 
on the side of the tail, and the scales of the sides larger thpn the rest, 
forming a corselet. The first has two separate dorsals, the others have 
the dorsal close; the former have small and the latter large strong teeth. 
The Tassards ( Cybium) differ from the three latter genera in having 
uniform small scales and sharp teeth. The other genera of this group 
have no keel on the side of the tail, large sharp teeth in front, and 
uniform small scales. The Thersites have two dorsals and a small 
ventral. Gempyles two dorsals and very small ventral. The Lepi- 
dopus a single long dorsal, scale-like ventrals, and a distinct caudal. 
The Trichiurus a single dorsal, and no caudal nor ventral fins. 
The second group has the muzzle elongated into a spike, and small 
velvet-like teeth. The Pike Fish ( Tetrapturus)\\we two keels on each 
side of the tail and long narrow ventrals. The Sword Fish ( Xiphias ) 
has only a single keel on the base of the tail and no ventrals, and a low 
dorsal, which diminishes in length as the animal grows ; and the Flying 
Sword Fish ( Notistium) differs from the latter in having slender ventral 
and a very high large dorsal fin, which enable it to swim with such velo¬ 
city that it can drive its beak through the stout oak planking of a ship; 
a piece of oak so pierced by the beak of a large specimen is exhibited. 
