INTRODUCTION TO THE CLASS OF REPTILES 



315 



south of that zone, reptilian life still is abun- 

 dantly represented, but chiefly by small species. 

 The largest land-serpents are found in the low- 

 lying, moist and hot forests of the equatorial 

 regions; but crocodilians of the largest size are 

 found several hundred miles from the equator, 

 both north and south. The largest tortoises live 

 directly on the equator. 



Poisonous Species. — Among our reptiles only 

 one lizard and a few species of serpents are ven- 

 omous, — an exceedingly small proportion of the 

 whole number. Indeed, so few in number are 

 the dangerous species of North America, it is 

 an easy matter for any intelligent person to 

 learn to recognize all of them at sight. In a few 

 hours of diligent and conscientious study, aided 

 by a text-book that has been properly designed, 

 any clear-headed person over fourteen years of 

 age can learn to determine almost at a glance 

 whether any fully grown serpent of North Ameri- 

 ca is poisonous or harmless. This is possible 

 from the fact that more than half of the venom- 

 ous species possess rattles, and those which have 

 not are few in number. 



Useful Species. — Many reptiles are of de- 

 cided value to mankind, by reason of the rats, 

 mice and other destructive vermin which they 

 destroy. Others diligently devour insects. Quite 

 a number furnish useful food, and some yield 

 skins and other commercial products of much 

 value. 



Lacli of General Knowledge Regarding 

 Reptiles. — ^While birds have been well taken 

 care of in books, museums, zoological gardens and 

 lectures, and mammals are now coming in for a 

 small proportion of the attention they deserve, 

 the reptiles have been greatly neglected. Very 

 few zoological institutions contain collections of 

 reptiles worthy of the name, and the books on 

 this Class are mostly to be written. As a result 

 of this well-nigh universal lack of opportunity 

 for study, the great majority of persons possess 

 very little precise and clear information regard- 

 ing these creatures. The following chapters are 

 offered merely as a foundation on which to build 

 an acquaintance with a world of living creatures 

 concerning which we are assured that a large 

 number of persons sincerely desire information. 



