CROCODILIANS, LIZARDS, AND SNAKES. 767 



between 7 .and 8 iuchos. From tlii^ nionuiut of escape from the egg al] were quite 

 active, and manifested many of the characteristics of the adults. Some of the little 

 fellows were quite saucy, and would make a pretense of striking at the approaching 

 finger, but their efforts in that line were rather feeble. A faint hiss was sometimes 

 uttered, but that may not have been voluntary. One would sometimes flatten its 

 head and bodj^ and rear up with the anterior third of its length free from the ground. 

 If one did not know well their iuoll'eusive natures, one would be excused for fearing 

 to handle them. An extremely singular habit possessed by the adults is that of 

 feigning death. On being struck or teased, they Avill roll over and over, as if in the 

 inteusest agony, and then throw themselves on the back, and lie there as if dead. 

 Out of some fifteen of the young experimented with, I succeeded in getting only 

 two or three to go through with this performance, but these did it to perfection. 

 On being lightly struck a few times, they would turn over on the back, writhe about 

 a while, and then lie perfectly still. If turned right side up they would again turn 

 on the back. If left undisturbed for a little while they would turn over and creep 

 slyly away. The others of the young would not act in this way, however much 

 they were teased. It would be interesting to know whether all the adults possess 

 this odd habit, or only a portion of them. 



The cuticle of the young Heterodons is shed very shortly after their escape from 

 the egg coverings. Within a few minutes after one had left its prison the skin was 

 observed to be broken about its head. It had left the egg at half past 1 and by 4 

 o'clock the skin was pushed back half the length of the body. The next morning 

 the skin was wholly shed, revealing the brighter colors of the new skin. While get- 

 ting rid of the cuticle the little fellow kept crawling over the clay and among the 

 roots of the grass. 



The opportunity was embraced to observe the use which is made of the egg tooth. 

 The tooth itself is easily seen in the just hatched snake. Its lateral borders are 

 more nearly parallel than those of the tooth of Bascanion figured by Weinland. Seen 

 from the side, the anterior or upper outline is concave, the posterior outline convex. 

 Thus the tooth projects forward and is slightly turned up. The anterior face is also 

 concave from side to side, so that there is, on each side, a distinct cutting edge. The 

 tip is cut oft' square. The tooth appears to have a ligamentous attachment, and may 

 be lifted a little, but not much depressed. It seems quite evident that the tooth is 

 first engaged in the egg covering, and then made to do its work by a forward push 

 of the head. An examination of the covering, after the snake had left it, gives 

 ample proof that it has been cut and not merely torn. The edges are as smooth as if 

 they had been slashed with a razor. A long slit is sometimes made as if by a single 

 effort. In other cases several attempts appear to have been made before the cover- 

 ing has been open enough for the snake to get out. In one or two cases a tooth has 

 not been inserted deeply enough, and the only result was a scratch on the inside 

 of the covering. The egg tooth having performed its office becomes loose and drops 

 out. This occurs usually within twenty-four hours. 



When the slit has been successfully made, the little snake may sometimes be 

 seen pushing its head carefully out as if to survey the surroundings. Should there 

 be any movement, the head will be quickly Avithdrawn. 



I have been able to collect some facts concerning the i)airiug of the sexes of Hete- 

 rodon. platirhinon. Prof. U. O. Cox, of Mankato, Minnesota, informs me that he found 

 two individuals uniting some time in May. A second male was entwined with the 

 two other snakes. The latter were separated with difficulty. The male intromit- 

 tent organs are described as being of an oval form, an inch long, and over half an 

 inch thick. 



Two observers have seen black specimens, formerly called H. niger, pairing with 

 the spotted individuals. Prof. W. S. Blatchley • found a black and a si)otted one 

 copulating on April 19. He speaks in a letter to me of the intromitteut organs as 



' Journ. Ciu. Nat. Hist. Soc, 1891, p. 33. 



