140 THE NAUTILUS. 



whorls five, slightly shouldered, body whorl mo-e swollen aperture 

 pointed and slightly expanded at junction with body whorl. 



REMARKS: Shell as broad as it is high. Figure 4 and 4a is the 

 nearest to normal obtained. In figure 13 we have all of the whorla 

 except the apical ones entirely separated. 



14. AMNICOLA EXPANSILABRIS n. sp. PI. 10, figs. 14, 14a. 



Shell small, whorls five and one-half, smooth, suture deep, umbil- 

 icus small, outer lip expanded and thickened. 



Height 3 mm. 



REMARKS: This species is the largest of all and is distinguished 

 by its form and thickened outer lip. Strongly resembles a species 

 of Pachydrobia, yet it may also be a pathologic freak. The above 

 three species seem to be distinct, the variations and deformations 

 may all be forms of one species. More material is necessary to de- 

 cide. They certainly form an interesting study for the evolutionist. 



Is it environment and food or salt and saltation? 



15. PLANORBIS ANTIQUITUS n. sp. PI. 10, figs. 16, 16a and 166. 

 Shell small, whorls four, rather flattened above, suture moderate. 



Lines of growth coarser and rougher as they approach the aperture. 

 The younger shell shows numerous very fine growtli lines, umbilicus 

 deep with straight sides, aperture flattened ovate, outer lip somewhat 

 expanded and slightly thickened within. The peristome thin, but 

 continuous in old specimens. The umbilicus shows more of the 

 whorls than the upper surface. 



REMARKS: This form belongs to the Planorbis bicarinatus group 

 and is quite distinct. 



NOTES ON COLLECTING SPHAERIUM AND PISIDIUM. 



BY JOHN A. ALLEN. 



In collecting Sphaerium and Pisidium I have obtained the shells 

 most copiously and with the least amount of labor and eye-strain by 

 the process described below. In Ohio the cold water and soft bot- 

 tom make rubber wading-boots necessary. The collecting tool is a 

 scoop ot wire netting sold as a kitchen utensil under the name 

 " strainer." The larger sizes, which are most efficient, usually need 

 some improvement by cutting off projections or strengthening with 

 solder. 



