Lesson VII.] 



NATURAL HISTORY. 



47 



and are therefore termed cold-blooded animals. Their peculiar characteristics are 

 oviparous reproduction ; low power of making heat ; peculiarity of protecting-surface. 

 by means of scales, or hard plates, and a heart with three cavities, one of which 

 receives the blood from the lungs ; another from the system generally ; and the third 

 propels the blood which is mixed in it partly to the body and partly to the lungs ; so 

 hen each contraction of the heart takes place, only part of the blood is aflected 

 by the air, and the consequence is, that their motions are sluggish, their sensations 

 dull, and their digestion slow. 



QUESTIONS. 



88. 7". What is the chief reason rep- 

 re separated from other animals ? 



P. Because the conformation of their 

 body is different, and also the circulation 

 of their blood. 



A Is not the blood perfectly oxy- 

 genated 



I 1 . No; because the nutritive functions 

 and power of circulation are feeble. 



90. T. Is it possible for reptiles to 

 suspend their respiration? 



I'. Yes ; because the smallness of the 

 pulmonary vessels enables them to do so 

 while submerged ; and thi> i> dom- without 

 e circulation of the blood. 



/'.Why are reptiles covered with 

 scales, or hard plates ? 



se, as they are not warm- 

 blooded animals, they are only covered 

 with a naked skin, which is not caj 

 retaining heat like those animals covered 

 with fur 



92. T. How are reptiles sutxlivi 



(ling to < 



\NS, or lizards. .'3. 'J 'in -Oi-in 

 or serpents. 4. Th- I'.M u \ IUANS, or 

 frtft, 



93. T. Is this arrangement satisfactory 

 to naturalists gent i 



P. No; and therefore they have adopted 

 that proposed by M. Brongniart, viz. 



\ss, or lurtifs a: 



' 



H, or serpents. 4. The 

 BATRACHIANS, or frogs. 



94. T Do reptiles incubate their eggs ? 

 P. No. 1 : Batrachians 



they h.i 



and in tin- Miakrv .ire tolerably 



advanced in their form when the egg is 

 depos 



I 95. T. Have not naturalists adopted 

 other divisii : 



P. Yes, but as they refer to other pecu- 

 liar characteristics, and the more especially 

 to extinct species, it does not belong to 

 this pan of our arrangement to consider 

 them. 



96. T. Are reptiles easily distinguished 

 from the other classes of vertebrate ani- 

 mals ? 



P. Yes, by their prominent peculiarities. 



97. T. What is the general locality 

 where reptiles are found ? 



P. In thickets, caverns, and dark 

 moist places. 



98. T. Is there anything peculiar in 

 the fourth order, orfrogi f 



P. They undergo a curious transform- 

 ation, especially the loss of gills, upon 

 attaining their perfect state. 



99. T. Explain and give account of 

 r.insformat. 



P It is well known to country people 

 who have been in the habit of seeing ditches 



ami ponds dtirinp the npring, that thrre are 



mill. luM.I hU inatses, resembling 



