46 



THE NAUTILUS. 



Operculum having the spiral rather large, the nucleus being 

 above the lower third. 



This little species resembles Lyogyrus by its tubular whorls of 

 small calibre. The whorls are more convex and increase less 

 rapidly than in Amnicola walkeriana, which is also less slender. 

 A. schrockingeri Ffld. has less deeply convex whorls, and the 

 apex is more acute. A. bakeriana is much larger, with a more 

 obtuse apex. 



Found in Short Point Bay, Oneida Lake, near shore, in 3 feet 

 of water, bottom of sand with algae; also in Lower South Bay, 

 etc. Collected by Mr. F. C. Baker. 



It is named for Dr. John M. Clarke, the distinguished Direc- 

 tor of the Museum of the State of New York. 



Amnicola oneida, n. sp. 



The shell is typically more slender than A. lustrica, turrited- 

 conic, narrowly umbilicate, corneous, minutely striate. The 

 apex is slightly obtuse, but the first whorl projects visibly, as 

 in lustrica, whorls very convex, parted by a deep suture. The ape- 

 ture is ovate, small, its length contained more than 3 times in 

 that of the shell; upper extremity narrowly rounded. The 

 peristome is continuous, thin, very briefly in contact with the 

 preceding whorl above. 



Length 4, diam. 2, length of aperture 1.25 mm.; 6 whorls. 



Lower South Bay, Oneida Lake, N. Y., collected by F. C. 

 Baker, 1916. 



This species is typically narrower than A. lustrica Pils., with 

 a smaller aperture and shorter whorls; but it is chiefly disting- 

 uished by the more convex whorls (deeper suture), and the 

 rounded instead of angular posterior end of the aperture. In 

 Paludestrina nickliniana the last whorl is much longer. Possibly 

 it may be a subspecies of lustrica, yet it has so distinct an ap- 

 pearance that a special name seems desirable. There are also 

 wider examples, which still differ from lustrica by the deeper 

 suture and aperture. 



