THE NAUTILUS. 



VOL. x. JUNE, 1896. No. 2 



NOTE ON NERITINA SHOWALTERI LEA. 



BY TVM. H. BALL. 



In February, 1861, Dr. E. R. Showalter of Alabama sent four 

 small shells without opercula or soft parts to Dr. Isaac Lea. They 

 were obtained ten miles above Fort William, Shelby Co., Alabama, 

 from the Coosa River. Three of these specimens are now in the 

 National Museum, with the original labels of Showalter and Lea. 

 The species was described under the name of Neritinu Shownltrri by 

 Dr. Lea, who observed that it was the first instance of the discovery 

 of true freshwater Neritina, like those of Europe, in our southern 

 waters. The note in which the description is embodied was read 

 Feb. 12, 1861 and published in the Proceedings of the Academy of 

 Natural Sciences, vol. xiii, p. 56, March 19, 1861, and also separ- 

 ately. 



Since that time for many years no notice of the species as collected 

 has come to my knowledge and I began to suspect that Dr. Showalter 

 had been imposed upon by some one who had given him, as obtained 

 from the Coosa River, some specimens of Neritina fluviatilis of Eur- 

 ope, to which these shells bear a marked resemblance, except that 

 they are smaller and without any dark markings upon the olivaceous 

 surface. It seemed very curious that a species of the section Theo- 

 doxus, to which Neritina fluvintilis is now referred, and which is not- 

 ably profuse in individuals when occurring at all, in Europe, should 

 be found only in one small stream in our Southern States and very 

 sparsely there. Of numerous collectors on the Coosa River since 



