56 THE NAUTILUS. - 



I may add that the /6^, bettii var. brevior of Smith, is in my opinion 

 distinct from S. bettii and should be raised as S. brevoir to specific 

 rank. I have examined a large number of both forms. S. bettii is 

 a species of the wooded zone, S. brevior of the dry zone. It is prob- 

 able that S. wolfi Reibisch may be only a variety of S. bettii. 



The final report on Dr. Baur's collections will not long be delayed. 

 The species will be figured and their anatomical characters dis- 

 cussed. The most important fact thus far determined is the close 

 alliance of all the Nesiotes, Rhaphielhis and Pleuropyrgus to the 

 American Bidimuli of the type of B. serperastriis. The diflTerent 

 forms of the shell are dynamic not genetic differences, and there is 

 no doubt as to the exclusively American type of the whole fauua, 

 when the groups represented are not of world wide distribution. 



PRELIMINARY NOTE ON THE SPECIES OF STROBILOPS.i 



BY H. A. PILSBRY. 



The United States species of this genus have generally been 

 believed to be but two in number, the "Helix'' labyrinthica of Say, 

 and Hubbardi of A. D. Brown ; the types of both being in the 

 museum of the Academy of Natural Sciences of Philadelphia. 



The writer some months ago, gave the varietal name virgo to 

 specimens sent him for determination by Rev. H. W. Winkley,^ and 

 later the name affinii to another form. 



Recently, with the assistance of Mr. H. E. Sargent, the various 

 species and varieties have been re-examined and compared, with the 

 result of finding that, in- what has hitherto passed as " H. labyrin- 

 thica, " there seem to be at least three well marked species. These 

 species agree in general form and sculpturing, but differ in size, 

 color, degree of depression, and especially in the internal lamelke of 



^Strobilops Pilsbry, Proc. Acad. Nat. Sci. Phila., 1892, p. ^0^,Serobila Morse 

 1866, not Strobila Sars, 1833, nor Strobilns Anton, 1839- 

 'Nautilus. 

 sProc. Acad. N. S. Phila., 1892, p. 404, (no description). 



