160 MOLLUSCA 



side out and the cement body and sperm mass are crowded 

 down the tube thus formed by the elastic force of the outer 

 tunic and the elastic and osmotic action of the middle tunic. 



The sperm mass is forced into a sac composed of the in- 

 verted inner tunic and outer membrane, which remain at- 

 tached to the bulge of the cement body; the cement body is 

 ruptured and the cement spread over the closed end of this 

 sac. The reservoir is now ready to stick in position. 



Studying the method of ejaculation is time consuming. 

 Fresh specimens placed in about one-fourth saturated solu- 

 tion of magnesium chloride for ten minutes or more will be 

 slowed in action so the process can be followed more readily. 

 Remove a specimen from this solution to sea water, grasp 

 the cap thread with forceps, and shake the spermatophore. 

 This should start ejaculation. Ejaculation can be stopped 

 promptly by squirting full strength formalin on the ejacula- 

 tory aparatus. 



Make a drawing of a spermatophore. 



Spermatophores are carried into position by the action of 

 the left ventral arm of the male. Examine its tip and notice 

 the modification of the suckers. 



Female Reproductive System. — The opening of the oviduct 

 has already been noticed. Observe: 



1 The large, swollen portion, the oviducal gland, that lies 

 on the oviduct dorsal to the left branchial heart. 



2. The long convoluted oviduct extending posteriorly from 

 the oviducal gland. It is frequently filled with eggs for the 

 greater part of its length. 



3. The lighter colored, greatly lobulated ovary, also fre- 

 quently filled with eggs, lying dorsal to the oviduct and vis- 

 ceral sac and extending from the region of the stomach to 

 the end of the body. The ovary is inclosed in a capsule from 

 which the oviduct leads. 



4. The nidamental and accessory nidamental glands have 

 been studied and removed. 



5. On the median line of the inner surface of the outer 



