LIMAX MAXIMUS LINN.^US 223 



mention the retractors of the tentacles. They have a common ten- 

 don attached to the body wall in the mid-dorsal line immediately 

 behind the mantle. The muscle runs beneath the loop of the 

 rectum and the coiled penis. On reaching the pharynx it splits 

 into a right and left bundle, the former passing above the penis. 

 Each bundle gives off again a smaller bundle to the anterior 

 tentacle. In the posterior tentacles the retractors split up also 

 into two bundles, one of which is attached to the eye, the other 

 to the wall in the olfactory region. 



Digestive system. The mouth is situated on the ventral sur- 

 face of the head and when closed has the appearance of a tri- 

 radial slit; two radii are directed obliquely forward, the third 

 backward. This is due to the fact that the mouth is provided 

 with two lips of which the upper one is almost triangular, while 

 the lower one is bilobed. The pharynx is almost globular and 

 the opening from it into the oesophagus is situated in its upper 

 wall. At the sides of this opening, but somewhat lower, there 

 are two small openings of the salivary ducts. The floor of the 

 pharynx is occupied by the radula. This is a chitinous curved 

 band with numerous rows of chitinous teeth. It is produced by 

 the secretion of the lining of the radular sac and may be moved 

 forward and backward on the floor of the pharynx by the action 

 of a protractor and a retractor or tensor. The former is situated 

 in front of the radula, under the epithelial lining of the floor of 

 the pharynx; the latter under the radula itself. The oesophagus 

 is a comparatively thin and short tube leading into a large 

 stomach. Behind the oesophagus is a pair of salivary glands, one 

 of which, the left one, is situated somewhat in front of the other, 

 but both are dorsal to the stomach. Their ducts open into the 

 pharynx. The stomach extends through two-thirds of the an- 

 imal's length. It leads into a long and coiled intestine. The 

 rectum is somewhat larger but considerably shorter than the in- 

 testine and opens through an amis into the mantle cavity 

 near the pneumostoma. The stomach, intestine and part of 

 the reproductive organs are almost completely surrounded by 



