148 ACANTHOPTERYGII. TEUTHIDID^. 



In form and general appearance tlie Spine-tails 

 resemble the Chsetodons, with which Linnaeus 

 associated them. They are marked by the body 

 being short, and greatly compressed ; it has been 

 stated, that " the depth of the body, measured 

 from the dorsal to the pectoral fins, is always 

 equal to, and often exceeds, its length from head 

 to tail ; " but this is certainly not the case with 

 the most typical forms. There are teeth only 

 in the jaws ; these are trenchant and denticulated, 

 like the teeth of a very fine comb : the mouth 

 is small, advanced, but not projectile. The fins 

 are much developed ; they are supported by nu- 

 merous slender rays, and are destitute of scales ; 

 the dorsal and anal are long ; and the caudal is 

 forked, the points frequently being produced into 

 filaments. But the most remarkable character 

 of these fishes is the presence of moveable spines 

 set on each side of the fleshy part of the tail, the 

 points and edges of which are as sharp as those 

 of lancets. With these weapons they inflict dan- 

 gerous wounds on the hands of such as handle 

 them incautiously. These lancets have procured 

 for them the familiar name of " Doctors," by 

 which they are generally known to sailors and 

 colonists. 



Genus Acanthurvs, (Lacep.) 



The sides of the tail in this genus are armed 

 each with a single lancet only ; the body is oval, 

 covered with minute scales ; the mouth very 

 small and projecting ; the dorsal is long and 

 undivided, supported, as is also the anal, by 

 numerous rays, of great slenderness, set very 



