14 



ZOOLOGY. 



Order 1. PLECTOGNAini. 

 " 2. lopiiobranchii. 

 " 3. Apodes. 

 " 4. subbraciiiata. 

 "• 5. Abdomikales. 



" 6. ACxlNTHOPTERYGII 



PI. Y4, fi(j. 52, Ortliagoriscus. 

 '' " 53, Ilippocam/pus. 

 " " 54, Anguilla., eel. 

 " " hQ^Pleuronectes', h^^Merlatigus. 

 " " 57, Cyprinus^ chub. 

 " . " 58, Xiphias.^ swordfish. 



Class 2. Iteptilia. 



Eeptiles are cold-blooded vertebrata, wliich breatlie by means of lungs, 

 or lungs and gills. The heart is composed of a large ventricle with which 

 tlie 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 

 tlie two ventricles transmits unmixed oxygenated blood to tlie 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 nnlike those of fishes. The first order is named Batrachia by Cuvier, 

 and AmpMhia by other authors, on account of their adaptation to breathing 

 both air and water at the same time, or at dilferent periods of their lite. In 

 some of the amphibia the gills are permanent {GnesiohranoMata)^ and in 

 others they disappear {Agnesiohranchiata). 



Order 1. Batrachia. PI. 74, figs. 59, Salamandra; 60, Banco. 

 " 2. Ophidia. " " 61, Vipera; 62, Boa. 



" 3. Sauria. " " 63, Anguisi 64, Ophisaurus ; 65, 



Clnrotes ; ^Q>.^ 67, Chalcides; 68, Bipes ; 69, Anolis ; 70, 

 • Scinciis ', 71, Tlliciia', 72, Ghamoileo; 73, Ptyodactylus j 



^i, BasiliscuSf' 75, Iguaiia ,• 7 Q, Draco j 77, Aga?na,' 78, 

 Stellio ; 79, Lacerta; 80, Tejus; 81, Grocodilus; 82, 

 Plesiosaxirus ; 83, Iclitliyosaurus. 

 Order 4. Cheloxidea. PI. 74, figs. 84, Ghelonia ; 85, Testudo. 



Glass 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 tiieir specilic 

 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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