Art. 11 NEW FEESH-WATER MOLLUSKS MARSHALL 3 



(Pliocene) of central Florida, but is more compressed vertically. 

 It differs from P. glahratus in having more whorls, in greater size 

 and in the semisoliite appearance of the whorls in the spire and 

 umbilicus. 



NOTES ON SE^^;RAL SPECIES OF PLANORBIS OF FLORIDA AND VICINITY 



The close relationship of fveglahrat'iis with the recent shell glab- 

 ratus naturally called attention to the latter species, and, while 

 studying the history of the latter, the following notes were made 

 concerning it and other species of Florida and vicinity. While 

 visiting the Academy of Natural Sciences of Philadelphia recently 

 its collection of Planorhis was examined and the subject was dis- 

 cussed with Dr. H. A. Pilsbry and Mr. Vanatta, who were able to 

 add additional information. Doctor Pilsbry in his study of the 

 Mollusca of the State of New York, to be published in the near 

 future, will go deeply into the history of some of the species of 

 Planorhis^ among them P. t/ivolvis Say, and P. lentus Say, P. hellus 

 Lea, and P. 'pseudotrivolvis Baker. Hence a discussion of these 

 forms is unnecessar}^ here, although P. trlvolvis is found in Florida 

 and the others found elsewhere are not distinctly separable from it. 



Pilsbry ^ has said : ^''Planorhis glahratus Say has not been found in 

 Mexico ; nor does it range in the United States, outside of the penin- 

 sula of Florida. The P. glahratus of author's is not the true glah- 

 ratus of Say." According to Bryant Walker,^ '■ Haldeman's and Bin- 

 nej^'s figures do not represent this species, which is entirely distinct 

 from ti^ivolvis. It is not uncommon in Florida and in the United 

 States does not range outside of that State. * * * The true 

 glahratus belongs to the section Planorhma and not to Plerosoma.''' 



The specimen figured by Binney * in Land and fresh-water shells 

 of North America, part 2, is in the National Museum (Cat No. 

 29219) with the locality doubtfully given as South Carolina. Speci- 

 mens catalogued under No. 8500 by Binney in the above-mentioned 

 work are still here under that number and come from St. Simon's 

 Island, Georgia. None of these specimens agrees with Say's descrip- 

 tion of P. glahratus, nor do eleven specimens (Cat. No. 120984), 

 nor six specimens (Cat. No. 28212), both lots froru St. Simon's 

 Island. Pilsbry and Walker are right in saying that the P. glahratus 

 of authors is not the P. glahratus of Say. 



The large, flattish, glossy shell now generally accepted as 

 P. glahratus Say, is the only species that fits Say's description, 



2 Land and fresh water shells collected In Yucatan and Mexico, Proc. Acad. Nat. Sci., 

 Phila., p. 321, 1891. 



= Synopsis of the classification of the Fresh-water Mollusca of North America, North 

 of Mexico, and a catalogue of the more recently described species with uotes, Univ. of 

 Michigan, Miis. Zool. Miscell. Publ., No. 6, p. 09, 1918. 



* Smiths. Misc. Coll., No. 143, p. 106, flg. 179, ISO? 



