ANODON. 
273 
Trans, vili. t. 3. a. f. 4. — Anodonta crassa. Marlas,, MSS, 
— Mytilus (A.) piscinalis. Gass, Moll, Agen. 191. t. 4. f. 1. — A. 
subponderosa. Dupuy, Cat n. 29. —A. Kossmassleriana. 
Dupuy^ Moll, Gers. 74. — A. Dupuyi. Ray and Brouet,, 
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. 417—420. 
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 
