118 THE SNAIL 



Pin out the collar on each side so as to expose the following internal 

 organs : — 



A. The Alimentary System. 



The mouth leads into a swollen pharynx or buccal mass, the ventral floor 

 of which bears the rasping organ or odontophore. (See page 124, Section D.) 

 The pharynx is succeeded by a short gullet or oesophagus, which passes into a 

 large thin-walled crop. On each side of the crop lies a large salivary gland 



/ AlBumen gland 

 Spermathecal sac 



Int. 

 FiQ. 37. — Dissection of the Snail (Helix), showing the alimentary and reproductive systems. 

 For "Stomach " road " Crop," and for " Intestine " read " Stomach." Int. indicates the Intestine. 



which sends a duct to open into the pharynx. The salivary glands are joined 

 together at their middle by means of a bridge of tissue. Following the crop 

 is the stomach, a somewhat dilated loop into which the ducts from the liver 

 or digestive gland open. Continuing from the stomach is the long intestine, 

 which coils throughout the substance of the liver and passes forward as i the 

 rectum, opening to the outside at the anus, as already noted. 



B. The Reproductive System. 



Insert a pin into the large muscular dart sac, and pin it out on the right side 

 of the animal. Put a pin through the loop of the vas deferens, and pin it out on 

 the left side. Note the common duct, a much convoluted tube composed of a 



