EEPEODUCTIVE SYSTEM 69 



perforate the hinder septa of their respective 

 segments (x. and xi.), and are continuous with 

 the vasa efferentia. 

 d. The vasa deferentia. From the posterior end of 

 each seminal funnel a fine convoluted tube, the 

 vas efferens, runs outwards and backwards on 

 the ventral body-wall. The two vasa efferentia 

 of each side unite in segment xii., and the vasa 

 deferentia so formed run back to open to the 

 exterior by the apertures already seen on the 

 ventral surface of segment xv. The vasa de- 

 ferentia are slightly imbedded in the body-wall, 

 and their exposure requires care. 



Microscopical examination of the reproductive organs, 

 and of their contents. 



a. The ovaries. Bemove an ovary entire ; stain with 



carmine or magenta, and mount in glycerine ; or 

 dehydrate, clear, and mount in balsam. 



The proximal and thicker end of the ovary 

 is a solid mass of cells from which the ova 

 are formed: the distal portion contains ripe 

 ova. Each ovum is a large cell with very dis- 

 tinct nucleus and nucleolus. The nucleolus is 

 stained by carmine more deeply than the rest of 

 the cell. 



b. The receptacula ovorum. Bemove one and examine 



it aslabove. 



Ova may be seen in it at certain seasons. 



c. The contents of the spennathecae. Bemove a sperma- 



theca and transfer it to a slide. Tease it in water 

 and examine with low and high powers. 



The seminal fluid in the spermathecas con- 

 tains innumerable mature spermatozoa, each of 

 which is an exceedingly fine filament with a 

 slightly thickened rod-like head at one end. 



d. The testes. Bem^ove a testis ; stain, dehydrate and 



