112 LABROIDS. 



being thus independent of the superincumbent weight, freely yields 

 to the absorbent process consequent on the growth of the new tooth ; 

 and before the latter becomes subjected to any pressure from above, 

 its formation has been su65ciently perfected to enable it to sustain that 

 pressure without injury. 



The lateral walls of the cavities containing the reserve teeth, to 

 which the pressure is transferred from the margins of the sockets of 

 those in use, consist of a much denser osseous tissue than the other 

 parts of the pharyngeal bone. 



The Wrasses feed on testaceous Mollusks, Crustaceans, Echini, 

 &c., which they seize with their long anterior conical teeth, and 

 crack and bruise by means of their powerfully armed pharyngeals. 

 Some of the sub-genera of Labroids, Epibulus and Clepticus, have the 

 intermaxillary bones provided with very long ascending processes, 

 and an arrangement of muscles, which producing a rotatory motion 

 of the maxillaries and a sudden descent of the intermaxillaries, 

 accompanied at the same time with a protraction of the lower jaw, 

 produces a tubular elongation of the whole mouth, and adds to their 

 power of catching the smaller marine animals. 



48. Scarus.{l) — There is a genus of fishes adapted to browse on the 

 lithophytes which clothe, with a richly tinted verdure, the bottom of 

 the sea, as the ruminant quadrupeds crop the herbage of the dry land. 



The irritable bodies of the gelatinous polypes which constitute 

 the food of these fishes retract, however, when touched, into the star- 

 shaped cavities of their stony support, and the Scari consequently 

 require a dental apparatus strong enough to break away and reduce 

 to a pulp these calcareous recesses. Their jaws are, therefore, pro- 

 minent, short, and stout, and the exposed portions of the inter- 

 maxillaries and premandibulars are shaped like the beak of a parrot, 

 whence the name of '* parrot-fish," usually given to these brightly- 

 tinted species of the Labroid family. But the mandibles instead of 

 being sheathed with horn, are encased by an extremely dense and 

 singularly complicated dental covering. 



Each intermaxillary bone presents a triangular form, with the 

 superior and posterior angles produced, and separated by an obUque 



Cl) PI. 49, 50, 51. 



