Grier: Morphological Features of Mussel-shells. 181 



25. Jennings, O. E. A Botanical Survey of Presque Isle, Erie Co., Pa. Annals 



of the Carnegie Mus:um, Vol. 5, 1909, p. 292. 



26. Johnson, O. W. Fauna of New England 13, List of the Mollusca. Occa- 



sional Papers of the Boston Soc. Nat. History, 7, 1915. 



27. KoFOiD, C. The Plankton of the Illinois River. 1894-99. Bulletin Illinois 



State Lab. Nat. History, Vol. VI, No. I, pp. 39, 43, 313, 1903. 

 Ibid., Vol. VIII, p. 24, 39-43, 313, 1908. 



28. Leverett, F. Glacial Formations and Drainage Factors of the Erie and 



Ohio Basins. U. S. G:ol. Sur., Bull. 41, 1902. 



29. Lewis, S. J. Quality of Water in the Upper Ohio River Basin and at Erie, Pa. 



Water Supply Paper 161, U. S. G. Survey, 1906. 



30. March, M. C. (Miss). Studies in Morphogenesis of certain Pelecypoda, I, A 



Preliminary Note on Variation in Unio pictorum, and Anodonta cygnea. 

 Mem. and Proceedings of Manchester Literary and Philosophical Society, 

 1910-11, pp. 1-18. 



31. Meek, F. C. and Clark, J. L. The Mussels of the Big Buffalo Fork of the 



White River, Arkansas. Report U. S. Bureau of Fisheries for igii. 



32. Newberry, J. S. Geological Survey of Ohio. Report L B., pp. 163-167, 



1873- 



33. Ortmann, a. E. a Preliminary List of the Najades of W. Pa. Ann. Car. 



Mus., 5, 1909, p. 192. 



34. Ortmann, A. E. A New System of the Unionidae. Nautilus, 22, 1910, p. 117. 



35. Ortmann, A. E. Monograph Najades of Pennsylvania. Mem. Carnegie 



Mus., IV, pp. 279-347 (191 1). 



36. Ortmann, A. E. Notes upon Family and Genera of Najades. Ann. Car- 



negie Mus., VIII, pp. 222-305 (1912). 



37. Ortmann, A. E. The Alleghenian Divide and its influence upon the Fresh 



Water Fauna. Proceedings American Philosophical Society, Vol. LI I, No. 

 210, pp. 275, 301, 305, 312, 351, 353 (1913). 



38. Ortmann, A. E. A New Type of the Nayad-Genus Fusconaia, Group of 



F. barnesiana Lea. Nautilus, 31, 1917, p. 58. 



39. Ortmann, A. E. The Nayades (Freshwater Mussels) of the LTpper Tennessee 



Drainage with notes on Synonymy and Distribution. Proc. American 

 Phil. Soc, Vol. 57, 1918. 



40. Rafinesque, C. S. Monographic des Coquilles Bivalves et Fluviatiles de la 



Riviere Ohio. Ann. G'en':r. Sci. Phys., Bruxelles, 5, 1820. 



41. Rich, S. G. An Aberrant Form of Unio complanalus Dillwyn. Science, 



N. S., Vol. XLII, No. 1086, 1915. 



42. Russell, I. C. Lakes of North America, pp. 34, 37, 41, 1895. 



43. Ruthven, a. G. a Biological Survey of the Sand Dune Region, South Shore 



Saginaw Bay. Michigan Geological and Biological Survey Pub. No. 4. 

 In Annual Report for 1910. 



44. Schermerhorn, L. Y. Physical Features of the Northern and Northwestern 



Lakes. Amer. Jour. Science, 3d Ser., Vol. XXXIII, 1887, pp. 278-284. 



45. Sell, H. Biologische Beobachtungen an Najades. Arch. f. Hydrobiologie 



iind Planktonkunde, 1907-08, pp. 179-180. Kopenhagen. 



