material. Professor Parker advised us to study the growth of some 

 of the land snails; and as a preliminary lesson, he set us to hunting 

 for some of the eggs in his snailery. After a few minutes' search, 

 George found a little cluster of eggs under a projecting clump of earth. 

 They were perfectly white, and about one-sixteenth of an inch in 

 diameter. 



The Professor told us that during May or June these snails lay 

 their eggs, to the number of forty or more, in moist localities where 

 they are sheltered from the rays of the sun. Favorite places are 

 under old leaves . which have space beneath them, by the side of logs, 

 stones, or sticks, and under loose pieces of bark or chips. Twenty or 

 thirty days after the eggs are laid, the young snail is hatched and 

 starts on its life journey, reaching full maturity in about three years. 

 In October or November, in this latitude (about 42 degrees north), the 

 snail ceases to be active and hibernates during the cold winter months. 



We asked Professor Parker how fast a snail could travel. This, 

 he said, was a part of the subject which he had never studied: so 

 he took a large specimen of the white-lipped snail from the snailery, 

 placed him on a board, and took out his watch. The snail hesitated 

 for a moment, and then started to crawl to the other end of the 

 board. In one minute it had crawled two inches. H-e then again 

 timed it, and it crawled twenty-four inches in fourteen minutes. He 

 then tried a snail of a different species, and found that it took this 

 snail two minutes to crawl two inches. Several other species were 

 tried, and it was found that eacli seemed to have a certain regular 

 speed, which did not vary to any great extent. 



Four species of orb snails, showing the under sur- 

 face of the foot as seen through the aquarium. 



1. Planorbis bicarinatus. 



2. Planorbis trivolvis. 



3. Planorbis campanulatus. 



4. Planorbis truncatus. 



38 



