156 GARDINER. [Vol. XI. 



most abundantly. Two dishes of salt water, both containing 

 these Turbellaria, were placed side by side near the window in 

 a well lighted room, and one of these dishes was covered by a 

 dark felt hat. At the end of the afternoon nearly twice as 

 many clusters of ova were found in the darkened dish as were 

 in the dish exposed to the light. 



The process of ovulation has frequently been watched with 

 a lens when the ova were being deposited on the side of a 

 fins:er-bowl or small dish. When the individual is about to 

 deposit its ova, it draws in all projecting portions of its body, 

 assuming the form of an oval disk so that at the first glance it 

 is difficult to distinguish the anterior from the posterior end. 

 Then the central part of the body is elevated so that a space is 

 left between the body and the glass. As the ova pass out of 

 the female genital pore they appear at first unsurrounded by 

 any capsule, but in the course of a few minutes they appear to 

 be contained in a clear transparent mucus mass. From two 

 to ten ova are thus deposited in each capsule. They are never 

 deposited in rows, but seem scattered irregularly through the 

 central part of the capsule, which is of much firmer consistence 

 on the surface than in the interior. 



Not infrequently the whole mass rotates several times before 

 it adheres to the glass. In capsules which are deposited on 

 the surface of disintegrating shells the upper surface is often 

 rendered partly obscured by the presence of fine particles of 

 the shell which adhere to the surface of the capsule during this 

 rotation. On one occasion a capsule was deposited on the side 

 of a glass dish where some finely powdered carmine had been 

 smeared, and the result was that the whole surface of the cap- 

 sule was covered with the fine colored particles. 



During the process of ovulation the animal is reluctant to 

 move, and on being disturbed with a needle or other instru- 

 ment contracts and shrinks from the contact, but leaves the 

 place it occupies much less willingly than under ordinary cir- 

 cumstances. When the disturbance is persisted in, the animal 

 moves off, trailing after it a line of mucus and eggs. Eggs 

 deposited thus unprotected by the full capsule seldom develop 

 normally. 



