Chap. XIII] GONADS OF CEPHALOPODA. 503 



As in the Lamellibranchiata, we find that a simpler 

 arrangement of ducts obtains among the Gastropoda 

 with separate sexes, the secondary glands and copu- 

 latory organs, which are so well developed in the 

 monoecious forms, being frequently altogether absent ; 

 this observation does not, however, apply to the 

 Cephalopoda, where we find several important and 

 instructive complications. 



As in some worms and nearly all Vertebrates, the 

 oviduct is not directly continuous with the proper 

 wall of the ovary, but the ova are set free into the 

 cavity of the capsule which encloses the ovary, to 

 be thence taken up by the open mouth of the 

 oviduct. This is either single or double, and has a 

 considerable extent, or only the terminal portion, of 

 its walls provided with secreting glands. Near the 

 orifice of the oviduct there open the ducts of two 

 large glands, which lie on the branchial cavity, and 

 which secrete a viscous substance, by means of which 

 the ova are massed into groups ; these are the so-called 

 nidamental glands. 



The vas deferens or duct from the testis, which 

 may or may not be double, is, like the oviduct, not 

 directly continuous with the gonad ; it is considerably 

 coiled, and glands or pouches are developed along its 

 tract ; of these the most important is that which is 

 ordinarily known as IVeedham's pouch, in which 

 are collected the masses of spermatozoa that have been 

 grouped together on their way down the duct (Fig. 209). 



These spermatophores are tubular structures, which 

 may be about half an inch in length ; the spermatozoa 

 are grouped together, and the rest of the cavity of the 

 tube is occupied by a coiled body ; when the sperma- 

 tophore escapes by the penis into the water the ex- 

 ternal sheath becomes ruptured, and the coiled elastic 

 band within being set free forces the sac of sperma- 

 tozoa out of the containing sheath (Fig. 210). 



