4 NAIADES OF MISSOURI 



Unionidae." For other personal help while attending the Uni- 

 versity thankful acknowledgements are due to Dr. R. I,. Moodie, 

 Messers. G. T. Kline and F. A. Sampson. Under the illustra- 

 tions of the new species (Plates v and vi) credit is given Mr. 

 Kline, the University Artist-technician, for his excellent draw- 

 ings. Through the kindness of Mr. vSampson, author of the 

 "MoUusca of Missouri" (Exclusive of the Unionidae), permis- 

 sion has been given to examine his collections of mussel shells 

 and make use of his list for same in determining geographic 

 distribution and in confirming the reports of other Missouri 

 collectors. Mr. B. F. Bush, a well-known scientist, and resident 

 of Courtney, Mo., has rendered invaluable aid in sending for 

 study immense collections taken mostly from the Ozark region 

 where the author has not been permitted to carry on such exhaus- 

 tive field studies as in the northern part of the vState. Material 

 from Missouri, contributed to the author's collection by Messrs. 

 C. C. Crouch of LaGrange, E. J. Palmer of Webb City and D. K. 

 Gregor of Fulton, has been thankfully acknowledged. The writer 

 is deeply indebted to old collectors and authors, who were former 

 residents of this vState, viz:— Messrs. C. T. vSimpson, W. A. Marsh, 

 Elwood Pleas and Dr. John H. Britts; also to those students of 

 Naiades for the nearest surrounding vStates viz: — Dr. F. C. Baker of 

 Illinois, Rev. W. E. Wheeler of Arkansas, Dr. D. H. Wolcott of 

 Nebraska, Dr. Junius Henderson of Colorado, Prof. F. B. Isely 

 of Oklahoma and Drs. R. E. Coker, Thaddeus Surber, A. D. 

 Howard, Prof. H. Walton Clark of Iowa. The last four named 

 students are of the personel of the U. S. Fisheries Biological Labora- 

 tory, located along the Mississippi at Fairport, Iowa, where the 

 author has done some study and has had pleasant personal contact 

 with these gentlemen who have contributed so much to the science 

 of Fresh-water Mussels. Besides being under obligations to the 

 above-named for their literary and conchological exchanges, as 

 well as for their valued correspondence and actual personal assist- 

 ance, special mention would also be made of Drs. A. E. Ortmann, 

 V. Sterki, C. B. Wilson, W. H. Dall, Harold Hannibal and Messrs. 

 B. H. Wright, Bryant Walker and L. vS. Frierson. The author is 

 most grateful to Dr. Ortmann as an authority concerning the soft 

 parts, to Mr. Walker for his treatment of the shell parts and to 

 Mr. Frierson for his general knowledge of Naiades as well as for his 

 special information concerning the Southwest forms. Through 



