Hurler — Herpetology of Missouri. 147 



in their eggs. The eggs of the oviparous species are fur- 

 nished with a thick, tough, flexible covering or "shell", 

 while the eggs of the species which produce living young 

 have coverings which are only thin and delicate. Now, 

 should such eggs as the latter be laid any considerable 

 period before the young are ready to be excluded, the 

 thin envelopes would surely be torn during the writhings 

 of the embryo. The eggs of the oviiDarous species are 

 laid a considerable time before they are hatched. The 

 tough coverings of such eggs protect them from attacks 

 and injuries from without and at the same time resist the 

 movements of the young snake within. So far as we 

 know these eggs are deposited in the earth in piles of 

 decaying vegetable matter and similar places. (Cope.) 

 A very curious structure deserves mention here. This 



is the "egg-tooth", a small tooth fixed to the united pre- 

 maxillary bones and projecting forward slightly beyond 

 the edge of the upper lip. It is present only in the em- 

 bryo and is shed shortly after the escape of the young 

 snake from the egg. The tooth is employed by the little 

 snake in ripping open the tough Qgg covering in its efforts 

 to escape from its prison. This tooth is found in all the 

 young just emerging from the egg^ of the oviparous 

 species. (Cope.) 



In Missouri all snakes hibernate. In summers with pro- 

 longed heat spells they become scarce, as the frogs and 

 toads on which a good many snakes live have hidden. 

 Sometimes we read in the papers of a " snake den ' ' hav- 

 ing been opened accidentally by "blasting", and a great 

 number of different snakes all coiled together encoun- 

 tered. This is only natural as all or most of the snakes 

 within a certain distance might have taken refuge in this 

 small cave over winter. Very likely the entrance to the 

 cave was just large enough for a snake to crawl into. 



I shall now give a resume of the classification of the 

 snakes proposed by Dr. L. Stejneger in his valuable work, 

 "Herpetology of Japan and Adjacent Territory," 1907, 



