1908. 



NATURAL SCIENCES OF PHILADELPHIA. 



421 



with Myriophyllum and Elodea, to see the effect of these water plants 

 and to discover whether or not their presence is beneficial. A priori 

 one would consider that the effect of these larger water plants as 

 Elodea or Myriophyllum would be beneficial. My experiments seemed 

 in indicate that their effect was the opposite. I at once started a great 

 number of experiments in this line. Some experiments, as can be seen 

 in Table I and Table II, went decidedly one way and some went 

 decidedly the other. The results were chaotic and no generalizations 

 were possible. 



A study of the gross anatomy of Lymncea reveals the fact that the 

 anterior portion of the stomach is highly muscular. This muscular 

 sac was originally described by Martin Lister '^ and compared to the 

 stomach of a mullet. Cuvier ('17) more happily compared it to the 

 gizzard of a granivorous bird. It was compared much later by the 

 geologist Whitfield ('82), independently of Cuvier, to the gizzard of a 

 fowl. Whitfield showed that this organ like the gizzard is normally 

 filled with sand in Lymncea megasoma. 



Table I — Effect of Elodea. 



5 Cited by Cuvif r ('17). 



