FEEDING HABITS OF FRESHWATER MUSSELS. 139 



Synedra Rhaphidium 



Triceratium Scenedesmus 



DESMIDACE.*:. Spirogyra 



Closterium Telraspora 



Netrium Uhthrix 



Staurastrum 1 Vaucheria 



MISCELLANEOUS CONTENTS. 



Inorganic fragments, 

 Plant and animal debris. 

 Mold, 



Ova and spermatozoa 

 Of other animals, 

 Of the same individual or species, 



(The sperm living and in motion), 

 Spores and swarm spores. 



The posterior half of the mussel shell, the part protruding 

 above the substratum, is usually very richly encrusted with 

 diatoms and other algae. This may serve as a private garden, 

 and particles dislodged by the passage of the animal along the 

 bottom thus be brought into the incurrent siphon. 



In addition to the very valuable assistance which I have 

 received from Prof. Scott, I wish to acknowledge by indebted- 

 ness to the John Crerar Library of Chicago, through which I was 

 able to procure several useful references, and to Profs'. C. H. 

 Eigenmann and \V. C. Curtis, who have made indispensible 

 critical suggestions. 



BIBLIOGRAPHY. 

 Call, R. E. 



'99 The Mollusca of Indiana. 24th An. Rept. Ind. Dept. Geol. and Nat. Res., 



PP- 335^535- 

 Conn, H. W., and Webster, L. W. 



'08 A Preliminary Report on the Algae of the Fresh Waters of Connecticut. 



Conn. State Geol. and Nat. Hist. Surv., pp. 1-78. 

 Coupin, H. 



'93 Sur I'L-limination des matieres etrangeres chez les Acephales. Compt. 



Rend, de 1'Acad. des Sci. Paris, CXVIL, pp. 373-376.! 

 Field, I. A. 



'09 The Food Value of Sea Mussels. Bull. U. S. Bur. Fish., XXIX., pp. 81-128. 



1 Also noted by Zacharias (/. c.). 



