116 SCAROIDS, 



Scarus spinidens, Quoy and Gaimard, the anterior denticles are imbri- 

 cated or arranged like tiles in several rows, and the lateral ones in 

 the upper jaw are always separated and pointed. There is, also, an 

 internal row of very small intermaxillary teeth. Cuvier has grouped 

 together the parrot- fishes with this type of dentition under the sub- 

 generic term Callyodon, which was apphed by Gronovius to all the 

 Scari. 



The parrot-fishes, like the wrasses, have no teeth on the supe- 

 rior maxillary, palatine or lingual bones, but are provided with 

 strongly developed pharyngeal bones peculiarly well furnished with 

 an apparatus of teeth for comminuting the coarse fragments of 

 blended gelatinous and calcareous matters, which the protruded jaws 

 are organised to break ofF.(l) 



Certain parrot-fishes in which the tooth-paved mandibles are 

 more slender and spoon-shaped than in the true Scari, and hence 

 probably subsisting on a different diet than the madrepores on which 

 such species browse, have the pharyngeal bones provided, as in the 

 Labri, with numerous obtuse rounded denticles, but more closely 

 packed together ; these parrot-fishes constitute the sub-genus Odax 

 of Cuvier. 



The typical Scari have both upper and lower pharyngeal bones 

 paved with strong thick lamelliform teeth, set vertically and trans- 

 versely in the opposed surfaces of those bones. It is the posterior 



(1) The general assertion by Cuvier, that the Scari, like the terrestrial ruminants feed 

 exclusively on vegetables, " comme les ruminans terrestres, le Scare ne se nourrissait que de 

 vegetavix," {Cuvier, Hisioire Natnrelle des Poissovs, torn, xiv, -p. 100) — must be received \vith a 

 certain restriction, although coming from an anatomist who so well understood, and who was 

 the first to describe intelhgibly, the plan and principle of the powerful and comphcated dental 

 armature of the parrot-fishes. It is true that Aristotle, in the passage quoted by Cuvier; 

 asserts that " the Melanurus and the Scarus subsist on sea-weed ;" but then the Greek Natu- 

 ralist also pushes the analogies of the Scarus to the terrestial ruminants so far as to 

 quote, and sanction, the behef that this fish actually ruminated. Some of the species 

 with weaker and sharper-edged mandibles may crop the sea-weeds as well as other sub- 

 stances, but both Commerson and Dussumier testify to the coral-feeding habits of the parrot- 

 fishes of the Isle of France and the Sechelles, etc. Mr. Darwin, who dissected several Scari 

 soon after they were caught, found their intestines laden with nearly pure chalk, and observed 

 that such, likewise, was the nature of their excrements ; whence he classes these fishes among 

 the geological agents to which is assigned the task of converting the skeletons of the Lithophytes 

 into chalk. 



