TEETH AND FOOD 137 



In most of the Wrasses {Labridae) the jaws are armed with 

 strong conical teeth, and the lower pharyngeals are joined 

 together to form a plate of characteristic shape studded with 

 blunt teeth (Fig. 54A), a dentition well adapted for dealing 

 with crabs and molluscs. The allied Parrot-fishes or Parrot 

 Wrasses {Scaridae) have the pharyngeal teeth forming a flat 

 pavement, the convex surface of the upper plate fitting closely 

 into the concave surface of the lower. In the jaws rows and 

 rows of tiny teeth grow up, but they remain fused together, 

 forming sharp-edged plates set in the short jaws, the whole 

 apparatus recalHng the beak of a parrot (Fig. 563). Most of these 

 fishes are vegetarian, biting oflf pieces of seaweed with their 

 "beaks" and grinding them up between the pharyngeal plates, 

 but others break off lumps of coral in order to obtain the 

 microscopic life contained therein, or prey upon hard-shelled 

 molluscs of the Limpet kind. The common Mediterranean 

 species, the famous Scams so much esteemed by the ancient 

 Greeks and Romans, is almost entirely a vegetable feeder, and 

 the sliding movements of the pharyngeals when engaged in 

 crushing pieces of weed led classical writers like Aristotle and 

 PUny to affirm that this fish "chewed the cud." 



A similar but even more complete fusion of the teeth in the 

 jaws is found among the members of the order of fishes known 

 as Plectognaths. In the Globe-fishes or Puflfers (Tetrodontidae) 

 the teeth unite to form sharp-edged plates, one on each side 

 above and below, and in the Porcupine-fishes (Diodontidae) , 

 feeding mainly on hard corals and molluscs, the teeth are 

 joined to form a single plate above and below, sharp at the 

 edge, but with a broad, crushing surface within. The small 

 mouth of the huge oceanic Sun-fish (Mola) is armed with a 

 similar beak-like dentition, but here the diet is composed 

 largely of other fishes. In the Trigger-fish {Balistes), also 

 pertaining to this order, each jaw is provided with eight strong, 

 chisel-like teeth, which are used to bore holes in the shells of 

 oysters, mussels, etc., in order to get at the soft parts. Curiously 

 enough, the related File-fish or Leather Jacket {Monacanthus) 

 has a somewhat similar set of teeth, although the diet is here 

 said to be a vegetable one. 



The members of the family of Cyprinids (Cyprinidae), including 

 such well-known forms as the Carp, Gold-fish, Tench, Roach, 

 Dace, Barbel, Bream, and Minnow, are distinguished by having 

 toothless mouths, but the pharyngeal teeth are well developed 

 and highly specialised. These are the leather-mouthed fishes 



