146 MOLLUSC A. 



(/) A branch leaves the narrow duct just before it enters 

 the hardening gland that leads to the curved anterior extremity 

 of the gland. This is the finishing duct. 



(g) The finishing duct leads to the curved gland mentioned, 

 the finishing gland. 



This completes the spermatophoric organ, although some 

 minor structures have not been mentioned. A section across 

 the ejaculatory apparatus gland will show a large ridge with a 

 groove along one side through which the spermatophore travels 

 and rotates while being formed. 



5. From the last part of the spermatophoric organ, the 

 finishing gland, a straight duct leads posteriorly by the side of 

 the vas deferens to join the spermatophoric sac about the length 

 of a spermatophore from its posterior pointed end. This is the 

 spermatophoric duct. 



6. The spermatophoric sac is somewhat spindle shaped, 

 usually filled with spermatophores, and joins the base of the 



penis. 



Make a drawing of the system. 



Open the spermatophoric sac and remove some of the 

 spermatophores. If the specimen has not been preserved place 

 them immediately in 10 per cent. formaUn or stronger to keep 

 them from ejaculating. Mount under a cover and examine. The 

 specimens may be stained with dilute Ehrlich's triacid stain and 

 mounted in glycerin jelly if preferred. Notice: 



1. The spermatophore is covered by a transparent elastic 

 outer tunic which has a cap and cap thread at the smaller, oral, 



end. 



2. Inside this is the somewhat granular middle tunic, which 



is much thicker at the aboral end. 



3. The contents consist of the aboral sperm mass, the oral 

 ejaculatory apparatus, and the cement body, which lies between 



them. 



4. The sperm mass may be seen to consist of a closely wound 

 thread. It is actually covered by a very thin inner tunic which 

 is separated from the outer tunic by a space filled with liquid. 



