14 ZOOLOGY. 
Orver 1. Prrcroenatat. Pl. 74, fig. 52, Orthagoriscus. 
‘© 2. LopHopRaNcuil. $ ‘“* 53, Hippocampus. 
BOS, AL POWE , - BA, Anguilla, eel. 
“ 4, SuBBRACHIATA. ss 5 BB, Pleuronectes ; 56, Merlangus. 
“5, ABDOMINALES. $ “ 57, Cyprinus, chub. 
“« 6. AcantoopTerren. “ = “ 58, Xiphias, swordfish. 
Class 2. Reptilia. 
Reptiles are cold-blooded vertebrata, which breathe by means of lungs, 
or lungs and gills. The heart is composed of a large ventricle with which 
the two auricles communicate. The ventricle receives venous blood from 
the system through the right auricle, and oxygenated blood from the lungs 
through the left one, so that both pure and impure blood are mixed in the 
ventricle, previous to being sent through the system, a portion passing 
through the lungs. This peculiarity of the circulation accounts for these 
animals being cold-blooded, since in the animals with warm blood, one of 
the two ventricles transmits unmixed oxygenated blood to the system. 
The brain of reptiles is small, and exercises less influence upon the 
system than in the higher classes, since they can live a considerable time 
when it is removed. The body is naked or covered with scales, but these 
are unlike those of fishes. The first order is named Latrachza by Cuvier, 
and Amphibia by other authors, on account of their adaptation to breathing 
both air and water at the same time, or at different periods of their life. In 
some of the amphibia the gills are permanent (Gnestobranchata), and in 
others they disappear (Agnestobranchiata). 
Orper 1. Barracuta. Pl. 74, jigs. 59, Salamandra,; 60, Rana. 
“ 2... Opmipra. s “ 61, Vipera; 62, Boa. 
3. Savgta. “ 638, Angus; 64, Ophisaurus; 65, 
Chirotes ; 66, 67, Chalcides,; 68, Bipes; 69, Anolis; 70, 
Semcus; 71, Tilicua; 72, Chamaleo,; 73, Ptyodactylus ; 
74, Basiliscus; 75, Iguana; 76, Draco; TT, Agama, 78, 
Stellio; 79, Lacerta; 80, Tejus; 81, Crocodilus; 82, 
Plestosaurus ; 83, Ichthyosaurus. 
Orper 4. Curtontpea. 7. 74, jigs. 84, Chelonia; 85, Testudo. 
Class 3. Aves. 
Birds are oviparous vertebrata, with warm blood and a double circulation, 
clothed with feathers, and provided with two feet and two wings. The air 
has access to various parts of the body, which diminishes their specific 
gravity, and assists them in flight. Of all the classes of animals this is the 
most strictly defined; and its characters are more uniform, and have 
fewer exceptions, on which account the classification presents some 
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