10 BATRACHIANS. 



All these creatures seem to have beeu well known to the 

 ancients. The monuments of the Egyptians abound in represen- 

 tations of Frogs, Toads, Tortoises, and Serpents. Aristotle was 

 well acquainted with their form, structure, and habits, even to 

 their reproduction. Pliny's description presents his usual amount 

 of error and exaggeration. Darkness envelops their history 

 during the middle ages, from which it gradually emerges in the 

 early part of the sixteenth century, when Belon and Ptondi- 

 Ictius in France, Salviani in Italy, and Conrad Gesner in Switzer- 

 land, devoted themselves to the study of ISTatural Historj' with 

 great success. In the latter part of the same century Aldrovandi 

 appeared. During fifty years he was engaged in collecting 

 objects and making drawings, which were published after his 

 death, in 1G40, edited by Professor Ambrossini, of Bologna, 

 the Reptiles tbrming two volumes. In these volumes, twenty-two 

 chapters are occupied by the Serpents. But the first arrange- 

 ment which can be called systematic was that produced by John 

 Ray. This system was based upon the mode of resp)iration, the 

 volume of the eggs, and their colour. 



Numerous systems have since appeared in France, Germany, 

 and England ; but we shall best consult our readers' interest by 

 briefly describing the classification adopted by Professor Owen, 

 the learned Principal of the British Museum, in his great work 

 on the Vertebrata. 



The two great classes Batrachians and Reptiles, include a 

 number of animals which are neither clothed with hair, like the 

 Mammalia, covered with feathers like the birds, nor furnished 

 with swimming fins like fishes. The essential character of rep- 

 tiles is, that they are either entirely or partially covered with 

 scales. Some of them — for instance. Serpents — move along the 

 ground with a gliding motion, produced by the simple contact 

 and adhesion of the ventral scales with the ground. Others, such 

 as the Tortoises, the Crocodiles, and the Lizards, move bv means 

 of their feet ; but these, again, are so short, that the animals 

 almost appear to crawl on the ground — however swiftly, in some 

 instances. The locomotive organs in Serpents are the vertebral 

 column, with its muscles, and the stifi" epidermal scutes crossino- 

 the under surface of the body. " A Serpent may, however, be 



