POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 247 



Movement 



The snail moves with a slow, gliding motion, produced by the 

 muscles of the pedal disk. First the hinder part of the foot Is 

 drawn up, and the part immediately anterior to it is extended. 

 This part is then contracted, and the part immediately anterior 

 to it extended. These movements take place the entire length 

 of the body, following each other so quickly that a gliding mo- 

 tion is produced. This contraction and expansion are confijied to 

 the central part of the pedal disk, the margins of the foot having 

 a lateral undulating movement of their own. 



The movement of the muscles of the middle part of the pedal 

 disk gives rise to a very peculiar appearance, as if there were a 

 channel through which oval drops of a transparent fluid were 

 rushing in quick succession. Each contraction and expansion of 

 the muscles of each part of the disk give the appearance of one 

 of these drops of fluid, and, as these movements take place in 

 rapid succession along the whole length of the foot, beginning 

 at the posterior and continuing to the anterior extremity, the 

 optical delusion of rushing drops of water is created. 



If a snail is placed on a thin piece of glass, and the under part 

 is observed while the snail is in motion, this movement can be 

 observed, or if a L i m a x is held with the fingers in such a 

 position that the under part of the body is uppermost, when it 

 struggles to escape the appearance is the same, the action of the 

 muscles being the same as when the animal is in actual motion. 



Food — carnivorous habits 



The snails which I have kept in confinement for three years 

 have been fed on apples and lettuce, and occasionally cabbage. 

 At first I placed lettuce in the box, but they refused to eat it. 

 After several days I placed pieces of apple in the box, and these 

 they ate ravenously. I fed them on apples for a uwuih or more, 

 when they seemed to tire of them and refused to ea(. After a 

 little time I placed lettuce in the box; this they ate. and since 

 that time it has been their i)rincipal food. 



