ANODON. 273 



Trans, viii. t. 3. a. f. 4. Anodonta crassa. Marks, MSS. 

 Mytilus (A.) piscinalis. Gass. Moll. Agen. 191. t. 4. f. 1. A. 

 subponderosa. Dupuy, Cat. n. 29. A. Rossmassleriana. 

 Dupuy, Moll. Gers. 74. A. Dupuyi. Ray and Drouet, 

 Rev. Zool. 1849, 14. t. 1, 2. Anodonta anatina. Pfeiffer, 

 i. 112. t. 6. f. 2. ; Schroet. Flussc. t. 1. f. 3. ; Rossm. Icon. 

 t. 30. f. 417420. 



Inhab. rivers, ponds, and ditches. 



Fig. 66. 



Anodon cygneus avonensis. 



The Anodons live in lakes, ponds, marshes, and 

 muddy rivers, crawling slowly on the mud, and 

 leaving a more or less marked groove after them. 

 In the winter, and especially in the summer when 

 the water dries up, they bury themselves in the 

 mud. They feed on decomposed animal and vege- 

 table substances; and the size and solidity of the 

 shell depends on the abundance of the food and 

 the state of quietness or motion and of calcareous 

 matter in the water in which they happen to reside. 

 Some authors have believed them to be unisexual ; 

 but their anatomy proves that they are hermaphro- 

 dite and sufficient for themselves. Pioret supposed 

 that of the two species he observed near Paris, one 

 was viviparous and the other oviparous ; but they all 



T 



