2l8 ELEMENTARY BIOLOGY. [CHAP. 



diverge, and at about one fourth the length of each 

 from its anterior end a short transverse branch unites 

 the two. The vas deferens arises a little in front of 

 the middle of each testis and passes without con- 

 volution towards the genital opening. Its distal half 

 is dilated. 



c. Tease out a bit of the testis in water, and examine 

 with \ obj. : it will be seen to be composed of 

 glandular tubes terminating in grape-like saccula- 

 tions. In it or in the vas deferens ripe spermatozoa 

 may be found : they are motionless and have the 

 form of discoidal cells provided with long radiating 

 processes. Stain with eosin, each will be seen to 

 contain 



a. The annulate corpuscle; a transparent ring, lying 

 within the middle of cell body. 



)8. The oval corpuscle ; a granular mass, lying to one 

 side of a. 



In the Lobster the spermatozoa are also motion- 

 less ; each consists of an elongated cell, from one 

 end of which three rigid pointed processes radiate. 



2. T\iQ female organs. 



a. The ovary ; in shape very similar to the testis of 

 the male, being bilobed anteriorly. 



b. The oviducts ; two short ducts which, like the vasa 

 deferentia of the male, are directly continuous with 

 the genital gland. They pass directly downwards 

 to the genital openings, and can be at once seen on 

 displacing the anti-penultimate walking legs to one 

 side (Sect. A. c. y). 



I 



