228 ZOOLOGY. 



like fine, close bristles, or cutting. Preoperculum occasionally spinous. 

 Dorsals either two or one. The Chcetodons, 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. Fl. 84, flg. 9, represents a common species of Chcetodon, C. auriga. 

 A, few species of Chcetodon 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. 

 tricolo?', found in the Gulf of Mexico, is shown in pi. 82, fig. 8. Another 

 genus, Dlpterodon, contains a single species, D. capensis (pi. 85, fg. 8), 

 from the Cape of Good Hope. The genus Amphiprion, a species of which, 

 A. hifnsciatus, is figured in pi. 85, fig. 9, is, perhaps, more properly referrible 

 to the family of Scienoids. 



The family of T^nioides is closely allied to the Scombridce, 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 ofl' 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. 8b, fig. 11, represents Trachypterus spinolce, 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 pi. 83, fig. 11. 



The family of Theuthyd^, with much the same general appearance 

 with the ScomhridcB, 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. ccerulus, 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- 

 432 



