388 REPTILIA. 



oviparous animals ; but when prepared for propagation they become 

 large, and the inside of the bag is lined with ova. There are two ovi- 

 ducts similar to those in the lizard 1 . The kidneys are long bodies on 

 each side of the spine, nearly the whole length of the abdomen. 

 There is a bladder of urine. \ 



The most extraordinary thing in this animal is the circulation, with 

 its dependent function, viz. respiration. In this respect it is a mixture 

 of the fish or Dicoilia, and the amphibia, or Tricoilia, having an open- 

 ing similar to gills, and lungs similar to those of the frog. Like the 

 fish, it has but one auricle and one ventricle, and of course but one 

 artery arising from the heart ; but this artery is very singular in its 

 distribution. 



The openings, which are similar to those of the gills in fish, would 

 seem not to answer any such purpose, for the arteries do not in the 

 least ramify so as to divide the blood, in order that it might be influ- 

 enced by respiration through these openings. This is one degree nearer 

 the Tricoilia than the other two. 



The auricle is large, and is placed principally on the left side of the 

 ventricle and behind. There is but one artery arising from the heart 

 or ventricle, which at first goes on towards the head, a little contorted, 

 and swells into a considerable bag: from each side of this bag are 

 given off four vessels, three of pretty considerable size, the other a 

 veiy small one, which is the first or undermost. This passes out late- 

 rally, adhering to the oesophagus, giving vessels to it, as it were, spent 

 upon it ; but one of its branches is joined by a branch from the second, 

 forming one trunk, which makes the pulmonary artery. This passes 

 down along the oesophagus, between it and the auricle, gets upon the 

 upper part of the lungs, along which it passes and ramifies. 



The second and third [aortic] branches, which are the largest, pass 

 outwards, but a little more upwards ; they both get upon the upper 

 part of the gill- opening, then pass along two bones which are pro- 

 bably intended as ' os hyoides,' and also for assisting in the dilatation 

 of this passage ; and, when got to the outer and posterior end, the 

 second sends down the branch to join the first, as above described ; and 

 then they [second and third] unite into one, there getting upon the 

 upper or posterior surface of the oesophagus, and sending several 

 branches to the head : when [the common vessel has] got to the middle 

 of the body, behind the oesophagus, it is joined by the branches of the 

 other side, which follow the same course. These four [aortic] branches, 

 two on each side, now form one trunk and pass downwards, behind the 



1 [Hunt. Prep. Phvs. Series, No. 3264.] 



