, | 
~ 
vou.x¥,] PROCEEDINGS OF THE NATIONAL MUSEUM. 395 
When the slit has been successfully made, the little snake may some- 
times be seen pushing its head carefully out as if to survey the sur- 
‘roundings. Should there be any movement, the head will be quickly 
~ withdrawn. 
& T have been able to collect some facts concerning the pairing of the 
_ sexes of Heterodon platirhinos, Prot. U. O. Cox, of Mankato, Minn., 
: informs mine 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 intromittent organs are de- 
| scribed as being of an oval form, an inch long and over a half inch thick. 
Two observers have seen the black specimens, formerly called H. niger, 
pairing with the spotted individuals. Prof. W. S. Blatchley* found a 
4 black and a spotted one copulating on April 19. Hespeaks in a letter to 
me of the intromittent organs as being as large as a walnut, and covered 
withspines. Mr. E.R. Quick, of Brookville, Ind., an accurate observer of 
| nature, writes me that he onee found a black viper pairing with a spotted 
one. The time, he thinks, was late in June. The time of gestation of 
f thisspecies is not known. It may continue from spring until autumn. 
| Possibly the late-pairing individuals may retain their eggs until the 
next spring. Nor do we know how long the eggs are laid before they 
| are ready to hatch. These matters are known concerning very few 
| of our snakes, and a wide field is offered for work and observation. 
~ Of the Colubers, T have been able to make observations on C. obso- 
letus alone. Itis likely that others have observed and written on the 
subject, but I have not met with their statements. Dr. G. B. Goode 
_reckonst this species among those which are ovoviviparous, but Tam 
inclined to question this. My son, W. P. Hay, captured two of these 
snakes, near Indianapolis, while they were in sexual union, This was - 
on June 19. The male (U.S. Nat. Mus., No. 17948) was 5 feet 5 inches 
‘long, the female (U. 8. Nat. Mus., No. 17949) 6 feet 3 inches. When 
they were separated, the intromittent organs of the male were everted 
some 3 inches. A dissection shows that the hollow portion of the organ 
extends behind the vent 3 inches, while the retractor muscles form a 
cord which extends back nearly to the tip of the tail. At the base of 
the evertible portion, near the vent, the inner surface, which when the 
organ is everted becomes the outer surface, is furnished with numerous 
plications. Near the middle of the organ are found many hooked 
 papille, some of them large and horny. The remainder of the organ 
has the surtace raised up into numerous anastomozing folds, so that 
~ under the microscope it reminds one of the reticulum of the ox’s stomach. 
_ On opening the female I find in her sixteen eggs. Of these eggs, four 
jie about the middle of the animal’s body, while the other twelve oc- 
| ¢eupy a much more anterior position; the one farthest forward being 
_ within 8 inches of the tip of the snake’s snout, the hindermost one only 
‘a * Jour. Cincinnati Soc. Nat. Hist., 1891, p. 33. 
pirog, A. Ay A. S. 1873) p. 185. 
