THK NAUTILUS. 21 



Amnicola Johnson!, sp. 



Shell umbilicate, globose, rather thin, pale brown, somewhat trans- 

 parent. Surface nearly smooth, showing faint growth-striae. Spire 

 short, obtuse. Whorls 3^, the first convex, planorboid above, the 

 rest very convex, somewhat flattened and strongly " shouldered " 

 below the sutures. Convex at periphery and around the circular 

 umbilicus. Aperture large, oblique, oval, somewhat angular above; 

 peristome thin, the outer and basal margins unexpanded, columellar 

 margin expanded above, not continuous across the parietal wall, which 

 is merely varnished by a light deposit, and is about half the length 

 of the free columellar lip. Alt. 2.7, diam. 2.56, longest axis of aper- 

 ture 1.7 mm. Operculum Amnicoloid. 



St. Augustine, Florida (C. W. Johnson). 



The conspicuously obtuse apex and globose contour are unlike any 

 other Floridian species, and somewhat similar to the much larger, 

 more solid and opaque northern porata form of Atnnicola liinosa 

 (Say). It is named after Mr. Charles W. Johnson, who collected 

 the series of some forty specimens in the collection of the Academy. 



Lyogyrus Dalli Pils. & Beech, is similar to the present species in 

 contour, but is smaller, paler, and differs generically in the closely 

 coiled operculum. L. gramnn (Say) has a decidedly more conical 

 and produced spire, rounder whorls, and, of course, differs in the 

 operculum. 



Paludestrina monas, n. sp. 



Shell turbinate-conic, rimate-perforate, thin, pale brownish horn- 

 colored ; smooth. Whorls 4, very convex, especially below the 

 deeply impressed suture, the apex obtuse. Aperture vertical, oval, 

 slightly narrowed at the upper extremity, the inner margin slightly 

 less orcuate than the outer ; peristome thin, the outer margin gently 

 expanded, a little sinuous, being produced forward below. Alt. 1.8, 

 diam. 1.3 mm. 



Wekiva river, Florida, with Lyogyrus Dalli and Amnicola sancti- 

 johannis (C. E. Beecher, February, 1886). 



In contour this species resembles Bythinella Aldrichi on a small 

 scale. The sinuation of the outer lip is somewhat like that of Pleur- 

 ocera, though much less pronounced. Something similar is found in 

 B. Hempliilli. 



The following species of this family are now known to us from 

 Florida : 



