558 







. 



CHAPTER XXI. 

 V. TELEOSTEA, OR BONY FISHES. 



I n this large order are many of the fishes which are most familiar 

 . o us. It is characterised, as we have said elsewhere, as a group of 

 i nimals having a solid skeleton. It is divided into six sub-orders ; 

 these are: i. P lectognatha. 2. Lophobranchia. 3. P haryngognatha. 

 4. Physostomata. 5. Anacanthina. 6. Acanthopterygea. All these 

 orders contain more or less familiar forms ; the first, contains the great 

 jun-fish, the globe-fish, and coffin-fish ; the second, the pipe-fish and 

 sea-horses ; the third, the flying-fish and the wrasser ; the fourth, the 

 ils, herrings, salmon, carp, &c. ; the fifth, the cod tribe and the 

 lat-fish ; and the sixth, the mullets, tunnies, gobies, perch, stickle- 

 backs, and many others. 



I. PLECTOGNATHA. 



From their organisation the fishes of this order seem to establish 

 the passage from the cartilaginous to the osseous fishes. Their skeleton 

 remains in a partly unossified condition. The bones of the head are, 

 however, perfectly solid. The cranial and maxillary bones are firmly 

 attached to the sides of the intermaxillary bones, and so form the 

 jaw ; the bones of the palate are united to the skull in such a manner 

 as to be motionless. The opercula and rays of the gills are hidden 

 under a thick skin, which leaves externally only small branchial slits. 

 These fishes have no true ventral fin, and the pectoral fins are small 

 and soft. 



This sub-order comprehends two natural families, characterised 

 by the armature of their jaws. They are the Gymnodonta and the 

 Sclcrodermata. 



In the family of Gymnodonta the jaws have no apparent teeth, 

 but they are covered with a plate of an ivory-like substance which 

 represents them. The Sun-fish, Orthagoriscus mola (Fig. 365), 

 belongs to this family. 



The Sun-fish (Orthagoriscus mola), Fig. 365, greatly reduced in 



