THE DEVELOPMENT OF FASCIOLARIA. 143 



the intra-cellular pressure, which varies with the size and number 

 of the vacuoles ('05). 



When the larvae have attained the external condition described, 

 the process of cannibalism begins. The eggs which up to that 

 time are quite uniformly scattered throughout the albumen of 

 the capsules are collected in more or less dense groups by the 

 action of the cilia around the mouths of the embryos. Some 

 hours after the eggs have been collected in the center of each 

 capsule smaller groups, still more densely packed, can be seen, 

 and at the end of two or three days all have been gathered into 

 from two to fifteen spheres which are the cannibals, stuffed almost 

 beyond comprehension. All larvae which secure sufficient eggs 

 finally have the appearance of the one shown in Fig. 3. 



FIG. 3. Fully gorged cannibal larva of Fasciolaria, //.?'., head vesicle. En- 

 larged 20 diameters. Drawn by Mr. Carl Kellner. 



This embryo is a fully gorged cannibal, so distended with eggs 

 that the body wall is scarcely visible, and the mouth and excre- 

 tory bodies are quite obscured by the dark background of yolk. 

 All that can be definitely made out is the folded and slightly 

 irregular head vesicle (Ii.v.') which marks the anterior end. 

 Larvae in this condition are comparatively regular, being in fact 

 nothing more than balls of eggs held together by exceedingly 

 thin transparent membranes. The diameters of fully gorged 

 cannibals vary from 1.16 mm. to 1.90 mm. depending on the 

 actual number of eggs that have been taken in. The average 

 diameter of larvae in this condition is about 1.48 mm. and one 



