( 90 ) 



57- *Of the fecretion in the crops of 

 breeding pidgeons for the nou- 

 rifhment of their young. 



OF AMPHIBIOUS ANIMALS. 



58. Of the heart and lungs of am- 

 phibia. 



Of the peculiarities in the flruc- 

 ture of thefe organs. 



59. Of the tranfverfe canals in the 

 feptum between the ventricles, 

 exemplified in the heart of a 

 turtle. 



Of the ufe of thefe canals. 



60. Why all the arteries proceed from 

 the right ventricle. 



61. Defcription of the circulation of 

 the blood in this clafs of ani- 

 mals. 



62. Ob- 



* See a Differtation on this fubjeft, and alfo an account of 

 the Air Cells in the Bones of Birds ; in Obfervations on cer- 

 tain parts of the Ardrnal (Economy, lately publiihed by Mr, 

 J, Hunter, 



