DEVELOPMENT OF THE COMMON FROG. 105 



the difference being that they were considerably larger, 

 and the club-shaped termination was broader and flatter, 

 and was marked by a faint indication of division into toes. 

 53 (4). By removing the skin of the ventral surface of 

 the body, the viscera were exposed : the parts seen were 

 the heart, right gill, liver, intestine, and pancreas. The 

 liver consisted of only two lobes, which were comparatively 

 small; and in the course of that part of the intestine which 

 was exposed to view was a globular enlargement apparently 

 in connexion with the pancreas. 



54. A drawing of the left hind limb was made; it 

 showed the divisions of the toes slightly more distinct than 

 before. 



55. A dozen tadpoles were taken from the pond; and a 

 drawing was made of the largest, the natural size. The 

 tadpoles were turned into a large basin of water and 

 watched ; they were seen to come to the surface from time 

 to time and put out their mouths, from which a small 

 bubble of air escaped. 



55 (2). The tadpole of which an outline drawing is 

 given was killed. The hind legs were considerably ad- 

 vanced, the toes being partially divided, and the knee and 

 ankle-joints indicated by bendings. 



Plate XIII. 



55 (3)- On taking off the skin from the chest and ab- 

 domen, the parts brought into view were the heart in the 

 middle and the gills on each side ; a transverse partition 

 separated them from the contents of the abdomen, which, 

 so far as they were visible with very little disturbance, 

 were the liver on the right side and the intestine on the 

 left, the coils of which were slightly opened out so that 

 they could be better seen. An enlarged drawing was made 

 of the whole body. 



SEK. III. VOL. VIII. 1 



