Jordan and Evcrmann. — Fishes of North America. 1689 



double. Mouth small, low; each jaw with a single series of narrow inci- 

 sor- like teeth ; vomer and palatines toothless ; premaxillaries somewhat 

 movable, but not protractile; maxillary short, closely united with the 

 premaxillary ; gill rakers obsolete ; pseudobranchiai large ; gills 4, a slit 

 behind the fourth ; gill membranes attached to the isthmus, the openings 

 thus restricted to the sides. A single dorsal fin, with strong spines, the 

 Bl^inous part of the tin shorter than the soft part; anal iiu similar to soft 

 dorsal; pectorals moderate; ventral lins present, thoracic, mostly I, 5 

 (never I, 4, 1, as in Siganid(B). Pelvis bones long, narrow, curved, closely 

 connected, evident through the skin, as in Balistidw, with which group 

 the Teuthididw have the closest affinities. Pyloric cajca rather few; air 

 bladder large ; intestinal canal long. Vertebrae 9 4- 13 = 22. Posterior 

 suborbital boues in close contact with the preopercle; post-temporal im- 

 movably united with the skull, apparently simple, but really trifurcate 

 with the interspaces tilled in with bone, the foramen not passing through 

 it; interneural bones with transversely expanded buckler-like subcuta- 

 neous j)lates, which interveue between the spines and limit their motion 

 forwards ; epipleurals developed from the ribs. Herbivorous fishes of the 

 tropical seas ; genera 5 or more; species nearly 80, most of them belonging 

 to Teuthis. These fishes undergo large changes with age, as is the case 

 with the Chaetodontida', the young having often been described as distinct 

 genera. (A'croniirida', Gunther, Cat., iii, 356, 1861 ) 



a. Caudal armature developed as a movable antrorse, extremely sliarp, knife-edged spine, 

 erectile from a groove. 

 6. Ventral rays I, 5 ; teeth fixed and strong ; dorsal spines usually 9. Teuthis, 664. 

 aa. Caudal armatiu-e developed as immovable tubercles or lamina. 



c. Ventrala I, 5 ; anal .spines 5 ; dorsal spines usually 8 ; caudal plates 3 to 6. 



Xesurus, 665. 



664. TEUTHIS,* Linnaeus. 



(Doctor-fishes.) 



Rhombotides, Klein, Missus (non binomial). 



ilepatws, Gronow, Zoophyl., 1765 (hepatxis; nonbinominal). 



Teuthis, Linn.eus, Syet. Nat., Ed. xii, 507, 1766 (hepatus ; javus ; after Hepatus, Gkonow). 



Acanthurus, ForskIl, Descr. Anim., 59, 1775 (Chcetodon unicornis) . 



Harpurus (Fokster) Gmelin, Syst. Nat., i, 1269, 1788. 



Aspisurut, IjACEPiiDE, Hist. Nat. Poiss., iv, 556, 1802 {sohar). 



Theuthis, Cuvier, Tab. El. Hist. Nat., 371, 1798. 



Tlieutis, Cuvier, Eegne Animal, Ed. 1, n, 330, 1817 (restricted to Les Acanthurus,- allies 



of Teuthis hepatus). 

 Teuthys, Swainson, altered orthography. 

 Rhombotides (Klein) Day, Fishes India, i, 202, 1876. 

 Acanthurus, of authors generally. 



* See Meek & Hoffman, Proc. Ac. Nat. Sci. Phila. 1884, 227-231, for the synonymy of the 

 American species of this genus, and Gill. Proc. U. S. Nat. Mus. 1884, 275, for the full syn- 

 onymy of the genera of this family and of the Siganidce. 



The name Teuthis has been transferred by Cantor and Giinther to the type of Teuthis 

 javus, the genus called Siganus, by Forskal, and Amphacanthus, by Bloch & Schneider. 

 The application of the laws of nomenclature here offers some difficulties, as the name 

 Teuthis was neglected by most followers of Linnaeus. Apparently, Dr. Gill is right in 

 applying the name to the present genus in place of Acanthurus, 

 3030 29 



