98 DR. THOMAS ALCOCK ON THE 



less disturbed, when they swam actively, but quickly 

 reattached themselves. 



25th. About a hundred tadpoles were reserved in the 

 basin and kept in the house for examination. 



27. Almost all of them were actively swimming about; 

 only a very few continued to use their suckers. 



One was killed, and a magnified drawing made of its 

 lower surface. On the right side the skin had completely 

 closed over the gills, the junction being effected by the 

 skin of the abdomen rising in a sharp edge and meeting 

 the edge of the opercular fold. The condition of the 

 opening at the left side, as represented in the drawing, 

 shows how the closure is effected, beginning at the middle 

 line of the body and extending outwards. The suckers 

 were thin and flat, and had evidently lost their function. 

 The mouth was large and the lips frilled. 



28. A drawing was made representing a tadpole, of the 

 natural size. 



28 (2). It was then killed, and a drawing made, under 

 the microscope, of the upper surface, showing the head and 

 body. The head was bluntly pointed in front, and broad 

 behind in consequence of the addition of the gill-chambers. 

 The eyes were still covered by the ordinary skin, which, 

 however, began to look thinner and more transparent ; in 

 the dead specimen they were opaque white. The body in 

 this, as well as in the two previous specimens, was fuller 

 from side to side, tending to give a depressed figure instead 

 of being compressed as at first ; the enlargement appeared 

 to be owing to the development of the abdominal viscera. 



Plate VIII. 



28 (3). A drawing was made of the under surface of 



a tadpole. It showed the completion of the chambers 



for the internal gills, leaving only an opening on the left 



side. The junction of the opercular fold with the skin of 



