504 COMPARATIVE ANATOMY AND PHYSIOLOGY. 



Though the germ glands of the higher Mollusca 

 are simple and similar in 

 structure, there is in some 

 a very complex system of 

 accessory organs. In the 

 hermaphrodite forms the 

 duct remains common for 

 a short distance only, and 

 its tract becomes compli- 

 cated by the development 

 of glandular bodies, the se- 

 cretion of which nourishes 

 or protects the ova, and of 

 pouches, in which the sperm 

 received during copulation 

 can be stored up till the 

 ova are ready for fertilisa- 

 tion. The male portion has 

 connected with it glands, 

 by means of which the 

 spermatozoa are massed into 

 spermatophores, and 

 the integument is invagi- 

 natedto form a penis, which, 

 when turned inside out, 

 forms a duct for the sperm. 

 In some cases also, as in 

 the snail, each individual 

 is provided with a gland 

 which secretes a chitinous 

 Pig. 209.- Male jDuct of Loiigo dart-like body (dart sac), 



, Penis ;^pouITLdha m ;c,vas which is thrown off from 



e:)te each 



, er snail at its mate 



ct) capsule in the Preliminary stages 



of copulation. 

 In some Cephalopods there is a still more remark- 

 able provision for the safety of the seminal products. 



