Anatomy of the Slug. 341 



S.D. Salivary duct. 



S.D.O. Opening of salivary duct into oesophagus. 



S.G. Salivary gland. 



SP. Spermatozoa. 



T.I. Inferior tentacle. 



T.S. Superior tentacle. 



U. Ureter. 



U.M.G. Unicellular mucous gland. 



U.O. Opening of ureter. 



V. Ventricle. 



VAC. Vacuole. 



V.D. Vas deferens. 



V.H. Visceral hump. 



V.P.G. Visceropleural ganglia. 



Fig. 1. Whole animal. 



Fig. 2. Reproductive system. 



Fig. 3. Teeth. 



Fig. 4. Reno-pericardial canal. 



Figs. 5 to 12 (inclusive) are typical transverse sections taken 

 in order, Fig. 5 being most anterior. 



Fig. 5, Section through buccal mass. Shows opening of 

 salivary ducts into oesophagus, and the anterior opening of the 

 pedal gland and posterior part of reproductive opening. 



Fig. 6 shows the opening of the amatory organ into the com- 

 mon genital atrium, and the invagination of the oviduct. 



Fig. 7. Section at level of the pulmonary opening, shows the 

 relative positions of the chief nerve ganglia. The tentacular 

 nerve crossing to the tentacle. 



Fig. 8 shows the otocysts in situ on the pedal ganglia. 



Fig. 9 shows the oesophagus surrounded by the salivary 

 glands ; the complicated nature of the common duct ; the 

 rectum just posterior to its opening to the exterior ; and the 

 albumen gland free from the common duct. 



Fig. 10. The manner in which the common duct becomes, as 

 it were, part of the albumen gland ; position of the salivary 

 glands ; opening of oesophagus into stomach. 



Fig. 11. Section just after the foot becomes free. Shows 

 hermaphrodite gland with spermatozoa very distinct; her- 



