ELEMENTARY ANATOMY. 



[LESS. 



called, excluding Whales and Porpoises (which, as we have 

 seen, are Beasts or Mammals) on the one hand, and Shell-fish 

 (which are Invertebrata) on the other. This class is divisible 

 into the following great groups : 



I. ELASMOBRANCHII. An order of highly-organized 

 cartilaginous fishes the Sharks (as Carcharias t 

 Cesti-acion, Spinax, the Hammer-headed Shark, 

 &c.), the Rays (including Raia, Myliobates, Areto- 

 bates, &c.), and the Chimaera. 



FIG. 30. THE HAMMER-HEADED SHARK. 

 (Zygaiia). 



FIG. 31. -THE EAGLE RAY 

 (Myliobatis). 



II. GANOIDEI. An important order containing many ex- 

 tinct forms, and a few very varied existing ones, as 

 the Lepidosiren, Ceratodits, Polypterus, Lepidosteus, 

 the Sturgeon, &c. 



FIG. 32. THE MUD-FISH (Lepidosiren}. 



FlG. 33. POLYPTERUS. 



III. TELEOSTEL The order containing the great bulk of 

 Fishes, and including the more remarkable Siluroids 

 (as Bagrus, &c.), the File-fishes 

 (Batistes], the Trunk-fishes (Ostra- 

 cioti), the Angler (Lophius), and 

 Frog-fishes (Chironectes), the Eels, 

 Pike, Salmon, Carp, Hippocampiis, 

 Odontoglossum,\\\t Soles, and other 

 flat fishes (Pleuronectidce), the 

 Parrot-fish (Scants), and very many 

 others. 



IV. MARTSPOBRANCHIL The Lamprey and Myxine, or 

 the lowly-organized cartilag'nous fishes. 



FIG. 34 A FROG-FISH 

 (Chironectes), 



