10 



FIRST BOOK OF ZOOLOGY. 



bubble of air, which maybe seen escaping from the breathing- 

 orifice, as in Fig. 14, B. 



test 



A view from the back, 

 or dorsal view. 



8ide-vUio. 



-ventral view. 

 1 1. Tentacles. 

 6 6, Eyes. 



6, Breathing- on fico. 

 jTi, Mouth. 



Fig. 13. — A Feesh-'Water Snail seen feom above, from the Side, and fbom below. 



