44 Mr. E. A. Minchin. Note on the Larva and the 



FiG. 1. Newly hatched larva. 



region of the intermediate cells is generally marked by a slight con- 

 striction, giving a waist, as it were, to the larvae. The granular cells 

 are much fewer in number than the other elements, and are also of 

 much larger size, but there are gradations in this respect, those 

 placed at the posterior pole being much larger than those which 

 border upon the intermediate cells. 



During the free-swimming larval period, considerable changes take 

 place in the relative proportions of the different parts of the larvae. 

 In the newly hatched larva (fig. 1) the anterior ciliated region is 

 relatively large, with a very broad granular border to the cells, and 

 the posterior granular cells are few in number. The number of 

 granular cells now increases at the expense of the ciliated cells. 

 Some of the ciliated cells, by absorption of the internal refractile 

 portion of the cell, become intermediate cells, and these, in their turn, 

 absorb their flagellum, increase in size, and become granular cells. 

 This process goes on pari passu with a decrease in the granular 

 border of the ciliated cells. In the larva of about twenty-four hours 

 (fig. 2), the granular cells form a mass equal to that of the ciliated 

 cells, and the latter have now a very narrow granular border. In 



