PLECTOGNATHI. 179 



ORDER VI. PLECTOGNATHI* 



THE jaws, which in the past Orders are free, are 

 now so constructed that the bones of which they 

 are composed are soldered, as it were, together, 

 having no power of independent motion. The gill- 

 covers and rays are concealed under a thick skin, 

 through which there is only a small slit ; there are 

 only the vestiges of ribs, and the ventral fins are 

 wanting. 



FAM. I. GYMNODONTID^E.f 



In this family the teeth are so united as to pre- 

 sent the appearance of parallel plates internally, 

 but the whole resembling a parrot's beak. They 

 have the faculty of swelling themselves into a glob- 

 ular form, by filling their enormous stomachs with 

 air, and in this state they float on the surface, belly 

 upward, yet well defended by the spines with which 

 they are everywhere covered, stiffened and erected 

 by the inflation. In such a condition they have 

 been compared to the burr of a chestnut. The 

 Globe-fish (Tetrodon Pennantii^} is caught on our 

 own shores ; its back is a rich blue, its belly silvery, 

 with brown fins. 



The Sun-fishes (Cephalus Mola,$ &c.) have no 



* nXtJM*, plcko, to knit together, and yvti6os, gnathos, the jaw. 

 f Tup,vos, gymnos, naked, and cdovs, odous, a tooth. 

 Tiffffugis, tessares, four, and oSovs, odous, a tooth. Pennantii, from 

 Pennant, an English naturalist. 



K<paXj, kephale, the head ; mola, a shapeless mass. 



