THE NAUTILUS. 



VOL. XII. MARCH, 1899. No. 11. 



CATALOGUE OF THE AMNICOLID.E OF THE WESTERN UNITED STATES. 



BY HENRY A. PILSBRY. 



In the course of preliminary studies for a monograph of American 

 species of this family, projected some years ago by Dr. C. E. Beecher 

 and myself, I found that the Western species, or at least part of them, 

 have been very imperfectly understood by most conchologists who have 

 collected them. Thus, the name Bythinella or Pomatiopsis intermedia 

 has been applied to several distinct species of middle California, a region 

 where it does not occur. Bythinella binneyi and some Amnicolas have 

 been equally misunderstood, and some of the Fluminicolas need revi- 

 sion. I have, therefore, drawn up a list, with the localities of speci- 

 mens in the collection of the Academy, and descriptions of some new 

 species. 



With a view to extending our knowledge of the range of any of the 

 species, I will willingly examine and identify specimens of the group 

 for collectors desiring to have their shells compared with types or 

 typical specimens of the several species. 



The types of Amnicola limosa, A.micrococcus, Paludestrina Imitator, 

 P. stearnsiana, P. hemphilli, Fluminicola columbiana, F. me.rriami, F. 

 erytliropoma, Pomatiopsis binneyi and P. c.alifornica, as well as of the 

 synonyms Bythinella intermedia, Melania exigua and Amnicola turbini- 

 formis, and author's specimens or co-types of all of the other species ex- 

 cept Fluminicola seminalis, are in the collection of the Academy of 

 Natural Sciences. My opportunities for determining the status of the 

 various species, and their syuonymy, have therefore been favorable. 

 Genus AMNICOLA Gld. and Hald. 



A. MICROCOCCUS Pilsbry. Nevada: Small spring in Oasis Valley, 

 Nye Co. (Merriam); Aurora. Ksuieralda Co. (W. M. Gabb). Cali- 



