142 MOLLUSC A. 



(d) The narrow duct leads into a large blind pouch and is 

 the outer tunic gland. 



(e) The large blind pouch extends posteriorly nearly the 

 length of the organ and is the hardening gland. 



(/) 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, formalin 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 



