SAURIANS. 39 



any other preparation, and is known as rough tortoise shall, which 

 is afterwards manufactured in the same manner as horn. Bv 

 softening it by the action of hot water, and afterwards pressing, 

 it can be spread out, soldered or moulded into any required shape. 

 What is termed rw/j, or cast shell, is obtained by agglutinating, 

 by a similar process, the scrapings and powder, detached from the 

 ordinary shell, in fashioning, or giving it the desired dimensions. 

 36. The marine Tortoises, designated under the name ot' 

 SPHARGIS, have no covering composed of horny plates, but one 

 of a coriaceous skin, similar to leather. Only one species is 

 known, the Luth, which is found in the Mediterranean, and the 

 Atlantic ; it attains seven or eight feet in length. 



LESSON III. 



ORDER OF SAURIA. Organization. Classification. 

 FAMILY OF CROCODILIDA. Circulation. Habits. Crocodiles 



properly so called. Alligators. 



FAMILY OP LACERTINIOA. Characters. Monitors. Lizards. 

 FAMILY OP IGUANIDA. Characters. Dragons. Iguanas. 



Uasilisks. 



FAMILY OF GECKOTIDA. Characters. Habits. 

 FAMILY OP CHAMJELEONIDA. Characters Common Chameleon. 

 FAMILY OF SCINCOIDEA Characters Scinques Fossil Saurians. 



ORDER OP OPHIDIA, or Serpents. Characters. 



FAMILY OF ANGUINA Characters. 



FAMILY OF SERPENTIA, ^or True Serpents. Coluber. Boa. 

 Venomous Serpents. Rattle Snake. Trigonocephalus. 

 Vipers. Naia, or Asps. Effects and treatment of the bites 

 of Vipers, fyc. 



FAMILY OF NUDA. Characters. 



ORDER OF SAURIANS. 



1. The order of Sauria comprises all reptiles that resemble 

 lizards in their general conformation. Animals of this order 

 always have an elongated body, terminated by a tail of greater 

 or less length, and provided with extremities, which, with some 

 exceptions, are four in number. 



36. Flow are the Tortoises of the gmus Sphnrois characterised? 

 1. What is the general character of animali included in the order of 

 BaorUI 



