THE TANGS 



Faviily LXIII. Tcutliidida: 



Body oblong, compressed and usually elevated, covered with 

 very small scales; lateral line continuous; tail armed with i or 

 more spines or bony plates; eye high up; preorbital very narrow 

 and deep; nostrils double; mouth small and low, each jaw with 

 a single series of narrow incisor-like teeth; vomer and palatines 

 toothless; premaxillaries slightly movable, but not protractile; no 

 gillrakers; pseudobranchia; large; gill-membranes attached to the 

 isthmus, the openings restricted to the sides; i dorsal fin, with 

 strong spines, the spinous part of the tin shorter than the soft 

 part; anal siinilar to soft dorsal. 



Herbivorous fishes of warm seas, usually easily known by 

 the lancet-like spine on side of caudal peduncle. There are 

 about 5 genera and 80 species, most of the latter belonging to the 

 genus Teuihis. Only a few of the species are of any food- 

 value. There are in our waters 2 genera with about 6 species, 

 only a few of which are of any value for food. 



The American species of Teuthis may be distinguished as 

 follows: 



a. Outline rhomboid, the depth \\ in length; colour brown 

 washed with blue ; ca'ni/ens, 486 



aa. Outline ovate, the depth about 2 in length; colour brown, 

 never blue. 



/'. Caudal simply lunate ; licpatiis, 487 



bb. Caudal deeply emarginate. 



c. Upper lobe of caudal not filamentous; cresloiiis, 487 



cc. Upper lobe of caudal produced in a long hlament; 



bahianiis, 487 



The species of Tciilhis are known variously as surgeon-fish, 

 doctor-fish, lancet-fish, barbers and tangs; and among Spanish 

 fishermen as Barberos and Medicos — all of the same origin and 

 meaning the same thing; for the barbers were the first "me- 

 dicos " who combined the practice of phlebotomy with their 

 regular vocation. 



T. ca'nilens is one of our best known species, as it is 

 quite common from Key West to Bahia. It is the blue tang 



4S6 



