APPENDIX. 



I. —ON ASYNCHBONISM OF THE AITEICULAE CON- 

 TEACTIONS IN THE EEPTILIAN IIEAET.— May 14, 1859. 



Having occasion, in the beginning of August last, to inject the 

 arterial system of Scincus vaHegatus, I laid bare the heart to empty 

 the vessels by bleeding. I was astonished to observe what ap- 

 peared to be a want of synchronism in the movements of the 

 auricles. After a little observation, I was compelled to admit that 

 the two auricles did not contract synchronously, but that after the 

 ventricular diastole the right auricle began to contract, followed by 

 the left. I also observed that the contraction of the ventricle 

 began at its right side, in the neighbourhood of the pulmonary 

 artery, and terminated on the left or arterial sinus of the ventricle. 

 I now looked at Briicke's memoir in the Vienna Transactions, and 

 found that he had described a ventricular arrangement by which 

 venous blood only passes into the pulmonary artery in reptiles, that 

 the ventricle begins to contract on its right side, and afterwards on 

 its left. He takes no notice of any want of synchronism in the 

 auricular contractions. 



Messrs. Arthur and Stirling confirmed the observation on the 

 lizard, and were also inclined, along with me, to admit a somewhat 

 similar asynchronance in the auricular contraction in the frog, 

 although I knew of no arrangement by which this co-operates in 

 the sole transmission of venous blood to the lungs. 



I exposed yesterday the heart of a tortoise, by removing four 

 portions of the plastron with a trephine, in the presence of Mr. 

 Turner. The asynchronism of the auricles did not appear to me so 

 well marked as in tho bzard. Mr. Turner scarcely admitted its 



