262 THE AMERICAN NATURALIST. [Vol. XXXVII. 



longitudinal slit in the egg, sometimes there are several of these 

 slits ; in this lot the markings of the young snakes began to 

 show on those preserved on July 6, nineteen days before hatch- 

 ing. Another lot of 21 eggs of this spec ies brought in July n, 

 1902, in which the spotted color pattern had begun to appear on 

 the embryos were kept till some of them hatched on July 28, 

 seventeen days later, three young snakes which hatched, 

 measuring respectively 285, 300 and 303 mm. in length. 

 Another lot, obtained in 1900, contained among others, one egg 

 which, though entirely normal in external appearance, was very 

 abnormal internally, inasmuch as it contained two embryos, and 

 one of these was a two-headed monster. 



Occasionally an egg of this species is pyriform in shape, much 

 like a killdeer's egg, as was the case with one egg of the lot of 

 thirteen mentioned previously, and with one of a lot of five 

 brought in June 28, 1901. 



Another species whose eggs are sometimes brought in is the 

 Spreading Adder {Heterodon platyrhinus) . The eggs of this 

 species are about the same size and shape as those of the Black 

 Snake, but the skin of the egg is smooth and very thin, much 

 thinner than in any other species of snake whose eggs I have 

 handled. Like those of the Black Snake, the eggs of this 

 species are free, not adherent to one another in clusters. 



A lot of 13 eggs was brought in June 23, 1900, from which 

 embryos were put up from time to time, till a young Heterodon 

 was hatched from the last egg on Aug. 14, fifty-two days later, 

 the young snake 200 mm. 111 length, emerging from a longitudi- 

 nal slit in the egg ; the only egg in this lot measured was 39 

 mm. long by 29 in breadth and oblong in shape. 



Another lot of 26 eggs was brought in June 27, 1902 (ten 

 other eggs were said to have been broken when the lot was 



hatched from the last egg on Aug. 5, thirty-nine days later. 



laid sixteen eggs, similar to the two lots previously mentioned 

 but whiter in color, owing to their not having been in contact 

 with the soil. These eggs although only just laid, contained 



