66 FAMILIAR LIFE IN FIELD AND FOREST. 



throw himself about the body of his victim and 

 tighten his hold as one might tighten the cord about 

 a bundle by pulling the string ends. But the squeez- 

 ing of our American snakes is a more serious matter 

 for mice than men, so we will pass that, and devote 

 our attention to the snakes themselves. 



There are two distinct groups or families of our 

 snakes, one of which includes the poisonous rattle- 

 snake and copperhead, and the other all the non- 

 poisonous snakes. Here they are as defined by Prof. 

 S. F. Baird : 



Ceotalid^ : Erectible poisonous fangs in front ; 

 few teeth in the upper jaw ; pupil of eye vertical ; 

 deep pit on the side of the face between the eye and 

 nostril. 



CoLUEEiDiE : No poisonous fangs ; pupil of eye 

 round ; no pit, and both jaws fully provided with 

 teeth. 



According to Prof. Samuel G-arman, there are at 

 least four species of rattlesnakes east of the Missis- 

 sippi River ; but with one only will we have to do as 

 a barely common object of familiar life. This is the 

 Northern rattlesnake {Crotalus horridtis).* Length, 

 forty to sixty inches ; dark brown above, blotched 

 with brown, black, and tan somewhat diagonally ; 



* The nomenclature in every case is that of E. D. Cope, 1893. 

 Vide Proc. U. S. Nat. Mu., vol. xiv, p. 589. 



