380 IDIOPHYSICS. 



is languid, and their motion generally slow. The first order of rep- 

 tiles, Chelonia, or tortoises, have hard shells covering their backs, 

 and thinner ones on the under side ; with four feet, which like the 

 head can be either drawn in, or protruded, as in the land turtle. 

 The second order, Sauria, or lizard-like animals, covered with scales, 

 and most of them having four feet and long tails, includes the extinct 

 Ichthyosauri, with the plesiosaurus, and megalosaurus ; the Crpcodili, 

 or crocodile and alligator ; the Lacertidae, or lizards ; the Stellionidae, 

 or dragon, and ancient pterodactylus ; the Iguanidae, or iguana, and 

 the ancient mosasaurus and iguanodon ; the Geckotidae, or geckos ; 

 the Chamelionidae, or chamelions ; the Scincoidae, or scincus ; and 

 the Anguidae, or seps and bipes, resembling serpents. 



The third order of reptiles, Ophidia, or serpents, having the body 

 exposed, or slightly covered, and with no feet, includes the Anguinae, 

 or glass snake ; the Amphisbaenae, so named from the head and tail 

 appearing alike ; the Colubridae, or boa, anaconda, and blacksnake ; 

 the Viperinae, as the rattlesnake, redsnake, viper, adder, and asp ; and 

 the Coecilidae, or blindworm. The fourth order, JBatrachia, or 

 frog-like animals, with the body naked, and differing from the three 

 preceding orders in the heart having but one auricle, includes the 

 Anourae, or frog and toad ; the Urodelae, or salamanders ; the Am- 

 phiumidae, or hellbenders ; and the Sirenidae, or proteus and siren, 

 resembling eels. These last named animals, except the sirenidae, 

 change their primary fish-like form, at a certain age ; acquiring limbs, 

 losing their gills, and afterwards breathing like other reptiles. 



5. Ichthyology, is that branch of Zoology which treats of fishes; 

 the last division of vertebrated animals. They live solely in the 

 water, are oviparous, and very prolific ; they breathe by means of 

 branchiae, or gills, consisting of laminae covered with innumerable 

 blood vessels, which absorb oxygen from the air existing in the 

 water ; and most of them have a scaly covering, and swim by means 

 of four, or at least two fins, besides the tail : but in some of them the 

 scales and fins are wanting. They are divided into orders, distin- 

 guished by the fins and the gills. The first order, Jlcanthopterygii, 

 or spiny finned fishes, includes the Percoidae, or perch, rock fish, and 

 dragon weaver ; the Buccae loricate, or gurnard, genuine flying fish, 

 bull head, and father lasher ; the Sciaenoidae, as the king fish ; the 

 Sparoidae, as the sheephead ; the Scomberoidae, or mackerel, tunny, 

 sword fish, and pilot fish; the Mugiloidae, as the mullet; the Go- 

 bioidae, or blenny and gudgeon ; the Lophioidae, as the angler or sea 

 devil ; and the Labroidae, as the tautog or black fish. 



The next great division of fishes, is the Malacopterygii, or fishes 

 with soft fins, which compose the next three orders. The second 

 order, Malacopterygii abdominales, having the ventral or under fin 

 behind the pectoral or side fins, includes the Cyprinoidae, or the carp, 

 gold fish and silver fish ; the Esocidae, or pike, and a kind of flying 

 fish ; the Siluridae, as the cat fish ; the Salmonidae, or salmon and 

 trout ; and the Clupeoidae, or herring, shad, and anchovy. The third 

 order, Malacopterygii subrachiati, having the ventral fin under the 

 pectorals, includes the Gadoidae, or cod, haddock, and whiting; the 

 Pleuronectidae, or halibut, turbot, sole, and flounder ; and the Disco- 



