REPTILES. 195 
reptiles. Why this exception is made in this order we 
know not. 
321. In Fig. 158 (page 194) is represented the common 
Crocodile. Its muzzle is more elongated than that of the 
Alligators. That of the Crocodile of the Ganges, called 
the Gavial, is more prominent still, and it is terminated 
by a cartilaginous or gristly protuberance, in which are 
the openings of the nostrils. This animal is frequently 
twenty-five feet long, and is very formidable from its 
strength and ferocity. It is of great service in devour- 
ing the dead bodies of men and animals which are com- 
mitted to the sacred river, and which would otherwise 
taint the air in their decay. 
322. The Alligators or Caymans are less aquatic than 
the Crocodiles. They frequent swamps and marshes 
more than rivers. ‘They are very dexterous in catching 
fish. They sometimes drive a shoal of them into a creek, 
and then with open mouth plunge among them. They 
also catch pigs, dogs, and other animals that venture toe 
near the water. 
Questions. —W hat are the two great classes of cold-blooded Verte- 
brates? How do they differ in regard to heat from the warm-blood- 
ed? What expedients are adopted in the latter to prevent the heat 
from escaping? What is said of the name, Reptile? What is said 
of the skeleton of reptiles? What of their power of motion? De- 
scribe the circulation of the warm-blooded Vertebrates. Describe that 
of Reptiles. What relation has the peculiarity of their circulation to 
their motion? What is said of their tenacity of life? What be- 
comes of them in winter in temperate climates? What is said of the 
nervous system of the senses in reptiles? What is their food? What 
is said of the manner in which serpents eat? In what are reptiles 
like birds? What are the orders of reptiles? Describe the covering 
of Tortoises? What is said of life in them? What are their fami- 
lies? What is said of the Land Tortoises? Of the Marsh Tortoises ? 
Of the River Tortoises? Of the Marine Tortoises? Of the Green 
Turtle? What is said of the two groups of Crocodiles? What is the 
peculiarity in the circulation in this order? What is said of the com- 
\ mon Crocodile? What of the Alligator? 
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