228 ZOOLOGY. 
like fine, close bristles, or cutting. Preoperculum occasionally spinous. 
Dorsals either two or one. The Chetodons, belonging to this family, are 
remarkable for their brilliant colors, the rhomboidal body, and the curious 
property possessed by the species, Chelmon rostratus and Toxotes jacu- 
lator, of ejecting drops of water, with unerring accuracy, at insects which 
may be within a moderate distance of the surface. In China and Java 
they are kept in vessels for the amusement afforded in watching the 
dexterity with which they will bring down flies at the distance of several 
feet. Pl. 84, fig. 9, represents a common species of Chetodon, C. auriga. 
A few species of Chetodon are found in America, especially in the Gulf of 
Mexico. The genus Ephippus, represented by two species, is found along 
the coast of the United States, where it is known as angel-fish, moon-fish, 
‘three-tailed sheepshead, &c. An American species of Holocanthus, H. 
tricolor, found in the Gulf of Mexico, is shown in pl. 82, fig. 8. Another 
genus, Dipterodon, contains a single species, D. capensis (pl. 85, fig. 8), 
from the Cape of Good Hope. The genus Amphiprion, a species of which, 
A. bifasciatus, is figured in pl. 85, fig. 9, is, perhaps, more properly referrible 
to the family of Scienovds. 
The family of Taniorpzs is closely allied to the Scombride, under which 
head some authors include it; the principal distinction consists in the 
elongated flattened shape. The genus Trichiurus has the ventrals and 
caudal wanting ; the dorsal extending all along the back, which runs out 
into a long slender filament. A few small spines represent the anal. The 
mouth is well armed and large, the jaw projecting. The general appear- 
ance of this genus is that of a bright silver ribbon ; one species, Trichiurus 
. lepturus, is occasionally caught off the coast of the United States. In the 
West Indies it is called sword-fish, and sometimes attains a length of 
twelve or fifteen feet. A remarkable genus, Trachypterus, has the body 
ending in a caudal appendage of varied shape, and a second caudal stand- 
ing up vertically from the tail. The ventrals are more or less developed. 
Pi. 85, fig. 11, represents Trachypterus spinole, from the Mediterranean. 
Cepola has a long dorsal and anal, both reaching to the base of the caudal, 
which runs out to an acute point. Muzzle short and rounded. Cepola 
rubescens, in England called band-fish, is represented in pl. 83, fig. 11. 
The family of Tueurnypz, with much the same general appearance 
with the Scombride, the same armature of the tail, but in different develop- 
ment, a horizontal spine before the dorsal, &c., differs in the small non- 
protractile mouth, the single row of occasionally dentated trenchant teeth, 
the absence of teeth on the tongue and palate, &c., and the single dorsal. 
They are also generally herbivorous. The genus Acanthurus has cutting 
and serrated teeth, and a strong movable spine in the side of the tail, which 
is exceedingly sharp, and capable of inflicting a severe wound when incau- 
tiously approached. Several species are found off the coast of the United 
States, as A. phlebotomus, A. cerulus, and A. chirurgus. This latter 
species is represented in pi. 84, fig. 8. The genus Amphacanthus presents 
the highly remarkable and indeed unique feature, of an internal spinous 
ray to the ventral, as well as the one which is external. There is a con- 
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