376 REPTILIA. 



hatching, for the older they are [in the egg] the yolk is less : it passes 

 through the duct to the intestine near the stomach, and in the lower 

 end of the stomach I found a suhstance like the yolk. This is the 

 reason why such eggs have so little white and so much yolk beyond 

 those of the bird. 



Observations on Young Vipers. 



" Having cut off the head of a viper, it was soon after skinned, and 

 found full of young contained in their membranes, which, being cut 

 open, the young vipers came forth with much activity, one in particular 

 attempting to bite the nearest object as soon as released. The mouth 

 of one of these was examined, but no teeth observed. They were 

 immediately after put into a large wide-mouthed glass half -filled with 

 moss brought a few days before by the viper-catcher to keep the vipers 

 in. After a day or two they shed a cuticle, and were now more beau- 

 tiful than before, being covered with a bloom resembling that observed 

 upon the fruit of the plum-tree. 



" They continued alive for more than a month without receiving visibly 

 any food except what they appeared to lick with their tongues from the 

 moss, which was occasionally, when supposed to be dry, lightly sprinkled 

 with water. When about a month old, some young frogs were put into 

 the glass with them, but did not seem to be noticed. Teeth being now 

 observed, one of these young vipers being held by the skin of the neck 

 in one hand, and with the other the hinder leg of a frog was put to his 

 mouth, and being therewith irritated, he bit it. The frog did not seem 

 much disabled. Next morning the frog was found dead with this 

 remarkable appearance, viz. the side bitten appeared as if nicely 

 injected with a red liquor, the other side pale as when alive. 



" Being opened, the gall-bladder was much distended. 



" I am, Sir, your obliged humble Servant, 



" T. Lane." 



" Aldersgate, Aug. 2, 1778. 

 "To Mr. John Harder" 



The Rattle-Snake [Crotalus horridus, Linn.]. 



The rattle -snake appears to have but one hepatic duct, which is 

 continued into the gall-bladder ; but from the duct passes a vast number, 

 which may be analogous to the ductus communis, and enter the gut 

 after piercing the pancreas, which is a thick body attached to the gut 1 . 



1 [The hepatic duct is subdivided into a plexus near its termination in Python; 

 but, in Dn/inits, it is convoluted at the same part. Both apparently to prevent the 



