CHAPTER IV: SOFT-RAYED BONY FISHES. 



General features of Bony Fishes. Sturgeons. Tarpon. 

 Conger Eels. Morays or Painted Eels. Gar-fishes or Needle- 

 fishes. Flying-fishes. Opah or Moon-fish. Ribbon-fishes. 

 Deal-fishes. Oar-fishes. 



At the beginning of Chapter I it was pointed out that 

 the Bony Fishes (Pisces) form a class of backboned animals 

 quite distinct from the Sharks and Rays (Selarchii), and the 

 principal differences between a Selachian and a Bony Fish 

 were briefly indicated. Before beginning our survey of the 

 larger members of the class Pisces it will be best to consider 

 some of the more important features characteristic of the 

 Bony Fishes as a whole. 



The internal skeleton may be composed of gristle (cartilage) 

 or it may be bony, but there are always a number of more 

 superficial plate-like bones known as dermal or membrane 

 bones. Typical bones of this type are those forming the 

 greater part of the roof and floor of the skull and those sup- 

 porting the gill-covers. Actually, these bones have been 

 derived from scales, which at some time or other sank inwards 

 and came into more or less intimate contact with the box-like 

 cranium. Many of the dermal bones of fishes persist in the 

 higher vertebrates, and the large frontal bones of our own 

 skull had their origin in some of the bony scales on the upper 

 surface of the head of the ancestral fishes. 



The skeleton supporting the mouth has likewise undergone 



