IV.] THE COMMON SNAIL. 289 



diverticulum of the integument, opening below the mouth 

 by an expanded orifice." (Cf. Sect. A. i. c. )8.) 



Compare the same, as seen in a transverse section across 

 the foot. Note its thick glandular walls and central lumen. 

 It is accompanied on either side by a well-defined lateral 

 pedal blood sinus. 



G. The Reproductive Organs. 



1. Pin the animal down as directed in Sect. D., and re- 

 move the right half of the body-wall posterior to the 

 genital orifice, together with the rectum. Dissect oif 

 the visceral sac and examine in order — 



a. The ovotesiis or hermaphrodite gland; a small white 

 mass, buried up in a fossa of the right lobe of the 

 digestive gland. Remove sufficient of the latter 

 to fully expose it. 



b. The duct of the ovotestis or hermaphrodite duct ; a 

 short highly convoluted glistening white duct, 

 passing upwards from the ovotestis towards the 

 main mass of the reproductive apparatus. 



2. Remove sufficient of the right lobe of the digestive 

 gland to liberate the ovotestis and hermaphrodite 

 duct; note — 



a. The albumen gland; a large greyish white structure 

 lying, apex downwards, to the immediate left of the 

 duct of the ovotestis. 



This gland swells up very rapidly under water, in 

 the manner of the glandular segment of the Frog's 

 oviduct already described (p. 53). Dissection may 

 conveniently be carried on under weak alcohol. 



M. 19 



