PLEURONECTOIDS. 107 



bones, to that side which corresponds with the under or white surface 

 of the fish ; the pharyngeal bones are beset with similar teeth. 



In the Plaice {Plntessa), there is a regular curvilinear series of 

 about twenty teeth, which are miniature resemblances of the incisors 

 of the Sargus, in the left intermaxillary bone, and only three smaller 

 and ill-shaped teeth near the median extremity of the right intermax- 

 illary. A like disproportion in the number of the teeth prevails in the 

 premandibular bones ; there being about thirty incisors, similar to 

 those above in the left, and but two or three incisors in the right 

 premandibular bone. The dentigerous intermaxillaries and preman- 

 dibulars are stouter, more curved and longer than those of the opposite 

 side. 



The food of these ground-fish being below them, and the side of 

 the head being applied to the bottom, instead of having the mouth 

 opening symmetrically upon the under surface of the head as in the 

 Rays, the premandibulars and intermaxillaries corresponding with the 

 under or white side of the fish are elongated and curved, and the 

 teeth, if not restricted to them, as in the sole, are more numerous and 

 more regularly disposed, than on the corresponding bones of the 

 opposite side. 



The pharyngeal bones of the Plaice are paved with flattened molar 

 teeth, larger than the incisors, and generally presenting a cubical 

 form. 



The pectinated processes from the concave side of the branchial 

 arches are sharp-pointed, but do not support teeth. 



The Turbot {Rhombus) has numerous small unciform teeth in the 

 jaws, a small group of similar teeth on the palate, and others on the 

 branchial arches and pharjmgeal bones. 



In the Holibut {Hippoglossus) , the giant of the flounder-tribe, the 

 arrangement of the teeth is less unsymmetrical than in the flounder 

 or sole, there being nearly as many teeth on the left intermaxillaries 

 and premandibulars as on the right. Both these and the pharyngeal 

 teeth are conical, sharp-pointed, and recurved, and the same form is 

 presented by the minute teeth which are placed upon the branchial 

 arches ; the whole dental system thus presents a predatory character. 

 The intermaxillary teeth are arranged in two or three irregular 



