THE NACTILUS. 23 



The accuracy of that veteran collector, Henry Hemphill, as to its 

 occurrence at Antioch, California, quoted by Stearns (1881), is not 

 to be questioned. But the fact that there is no other record of its 

 occurrence in California certainly tends to show that the Antioch 

 find was a sporadic colony, accidentally introduced, and which never 

 succeeded in effecting a permanent foothold. 



The citation of this species from the Yaqui River, Guaymas, 

 Mexico, on the Gulf of California, by Stearns (1889), where it is 

 said to have been collected by Palmer, is open to more doubt. It 

 appears that Polygyra hirsuta was also alleged to have been collected 

 at the same time and place. The nearest authentic locality for this 

 species is southwestern Missouri. There is no evidence that bicari- 

 natus has ever been discovered anywhere in the Colorado basin. The 

 occurrence of two common eastern species at the same time in a 

 locality so remote from the known range of either is certainly very 

 remarkable, and would naturally raise a question as to whether there 

 had not been an accidental mixing of specimens. Bicaritiatus is not 

 quoted from Mexico at all by Crosse and Fischer, and its occurrence 

 at Guaymas is very improbable. 



Leaving these two doubtful citations out of the question, the only 

 authentic occurrence of bicarinatus on the Pacific coast is along the 

 Columbia in Oregon; south of that the Rocky Mountains, no doubt, 

 mark the western range of the species. 



In the Potomac River at and below Washington, D. C, bicari- 

 natus is an abundant species. South of that, with the exception of 

 Wilmington, N. C, so far as the records show, it is absent from the 

 entire coastal Atlantic region. In western North Carolina and 

 northwestern Georgia it is found in streams belonging to the western 

 drainage. We have no records from South Carolina and Florida. 

 The large amount of collecting that has been done in various parts 

 of the latter state goes to show that it does not occur there. South 

 Carolina is practically unknown conchologically. It was not found 

 by Henderson at Yemasee, Beaufort Co. (Naut. XXI, p. 7). Mr. 

 Wm. G. Mazyck, of Charleston, S. C, informs me tiiat he has 

 never known of its occurrence in that state, and that it is not quoted 

 in either of Ravenel's Catalogues of 1834 or 1874. In Alabama, 

 though not abundant, it occurs in the northern part of the state, and 

 extends in the Alabama drainage as far south at least as Pinehill, 

 Wilcox Co. There are no records for either Mississippi or Louisiana. 



