EXPLANATORY NOTE. 



In the fall of 1904, Mr. Herbert H. Smith began systematic collecting of the fresh-water 

 shells of the family Pleuroceridae of the Coosa River and its tributaries, for a syndicate of 

 four naturalists : Hon. Truman H. Aldrich of Birmingham, Mr. George H. Clapp of Pitts- 

 burgh, Dr. Henry A. Pilsbry of the Philadelphia Academy of Sciences, and Mr. Bryant 

 Walker of Detroit. Later Mr. John B. Henderson, of Washington, took Dr. Pilsbry's place. 



From the very beginning of the work Mr. Smith's fixed idea was to make as complete 

 a collection of Pleuroceridae as possible and — as customary with him — to study carefully as 

 he collected; his notes show this. 



Early in the fall of 1908, Mr. Smith came to the University at the request of Mr. Walk- 

 er, to study the fresh-water shells of the Schowalter collection in the Museum of the Geo- 

 logical Survey of Alabama (as it was then known) and, shortly afterward, accepted a po- 

 sition as Curator of the Museum. From that time until his death (March 22, 1919) he re- 

 tained this position, devoting much of his time to study of the Pleuroceridae. 



The working up of groups was divided between Mr. Walker, who took the Unionidae and 

 families of fresh-water shells other than the Pleuroceridae ; Dr. Pilsbry, the Pleuroceridae ; 

 and Mr. Clapp the land shells. Pressure of other work soon caused Dr. Pilsbry to drop 

 out and Mr. Smith took over the Pleuroceridae. 



He had been working a long time on the genus Anculosa preparatory to monographing 

 it, but this work was cut short by his death. 



At the suggestion of Dr. Walker, our specimens of Anculosa, with Mr. Smith's notes, 

 were turned over to Mr. Calvin Goodrich of Detroit, who was making a study of this group. 

 The results of Mr. Goodrich's painstaking investigations appear in this pamphlet (based 

 almost entirely on Mr. Smith's field work). In speaking of his own work Mr. Smith often 

 said : "If I never monograph them myself, at least I will make it easier for my successor." 



In 1920 (writing of Mr. Goodrich's pamphlet) Dr. Walker said: "It is a very fine piece 

 of work and will make an excellent monument for the work that Mr. Smith did in Alabama." 



The Geological Survey of Alabama had hoped to publish this monograph as one of a 

 series of technical papers dealing with various groups of animals (others on birds, amphi- 

 bians and reptiles having been published recently), but lack of funds has prevented. Owing, 

 however, to Dr. Walker's kind offices, the University of Michigan has published it (Museum 

 of Zoology Miscellaneous Publications No. 7), without expense to the Survey, except for 

 the paper, press work and covers of 500 copies which were printed as an edition to bear our 

 own cover and to be distributed by us. 



Our sincere thanks are due to the University of Michigan for its friendly co-operation 

 with the Geological Survey: to Dr. Walker for his kindly efforts to aid us in a time of need 

 and to Mr. Calvin Goodrich for his generous appreciation of Mr. Smith's work and his un- 

 selfishness in effacing himself as the describer of new species. It remains to add that Mr. 

 Goodrich is at work on another genus of the Pleuroceridae, Gyrotoma, which will be duly 

 published. 



Unfortunately, the opportunities for studying these and other shells in the Coosa River, 

 which has probably had the richest molluscan fauna of any stream in the world, (as stated 

 on p. 7), may be at an end after a few years, on account of the flooding of the shoals by 

 dams for navigation and power. 



For about 30 years past there have been four locks and dams for navigation on the river 

 in the Paleozoic region, between Grecnsport and Riverside. A seventy-foot dam for power 

 purposes was built in the region of the crystalline schists in 1914, backing the water for many 

 miles, and another large dam just below (at Duncan's Riffle) is now ncaring completion. 



November, 1922. EUGENE A. SMITH. 



