An Evening With the Aquarium and Snailery' 



Frank Collins Baker. 



One evening, shortly after our trip to the woods, we met by 

 appointment at Professor Parker's home for the purpose of spend- 

 ing a few hours in study. The Professor greeted us in his usual 

 hearty manner, and we were soon deeply engrossed in our favorite 

 subject. 



Of great attraction to us was a large rectangular aquarium 

 (about two feet in length and one foot in width and depth) , which 

 was tenanted by various species of pond snails, and fresh-water 

 clams. A light was placed behind the tank, and thus we were 

 able to study the habits of the imprisoned animals. A clam was 



A Fresh Water Limpet 

 As Seen Through the Side of^an Aquarium. Greatly Magnified 



slowly pulling its shell through the muddy bottom, its siphons ex- 

 tended, and the little cilia moving nervously about. Professor 

 Parker told us to watch these siphons closely. A stream of water 

 was constantly passing down the lower siphon, a fact of which we 

 became aware by seeing several very small particles of vegetable 

 matter float near the siphon and quickly disappear into its orifice. 

 The upper siphon was violently expelling waste matter, and we 

 could see the little particles thrown out into the water. We no- 

 ticed that this siphon seemed to move like clock work, opening and 

 closing at regular intervals, each time ejecting a current of water 

 filled with waste matter. Out of curiosity we counted these pul- 

 sations and recorded twelve each minute. 



In another part of the aquarium, a number of pond snails were 

 gliding slowly along. On one side, several large snails were eating 

 the growth of of green vegetable matter which had accumulated. 

 This side presented a curious appearance, for each snail had 



^From "Shells of Land and Water," by permission of the author. 



3L5 



