J)- 



2 ELEMENTARY BIOLOGY. [CHAP. 



move the alimentary canal between the base of the 

 oesophagus and posterior third of the large intestine. 

 Next open up the latter, as directed in Sect. D. 4 ; wash 

 and examine under water. 



1. In both sexes. 



a. The kid?icys ; symmetrically disposed on opposite 

 sides ; relatively largest in the male. Each is 

 convex dorsally (outer border), incompletely lobed 

 on its inner border. 



h. The adre7ial body ; a band of yellow tissue running 

 along the ventral face of each kidney. 



c. The duct — ureter (female) or gemto-uri'?2a7y canal 

 (male) — running from the outer side of the pos- 

 terior part of each kidney to the cloaca. Open 

 the cloaca and pass a bristle into one of their 

 openings. 



In the male R. escule7ita each duct is somewhat 

 dilated after leaving the kidney : it then narrows 

 again and opens on the dorsal wall of the cloaca 

 by an oblique slit with sharply defined edges. 

 In ^. icmporaria the duct does not dilate, or only 

 very slightly ; but on its outer side lies a glandular 

 mass {yesicula seininalis)^ from the inner side of 

 which a number of minute ducts open into the 

 genito-urinary canal. The aperture of the latter 

 in the cloaca is round and has tumid edges. In 

 the female of both species the ureters are very 

 slender. 



d. The bladder; (cf. Sect. D. 4. c.) 



2. In the female. 



a. The ge?utal gla7ids {ovaries) (cf Sect. B. 2. //. p.); 

 varying much in size with the season of the year. 



