The Productivity of Fish Food in Oneida Lake 245 



There is also an abundant smaller form, resembling the 

 typical form in texture, apex and shape of the whorls, varying 

 in form, but relatively broader than the type. There are 

 some intermediate examples, but as Mr. Baker considers it 

 desirable to have a designation for this form, it may be called 

 A. hakeriana form nimia. The type measures: length 3, diam. 

 2.5, length of aperture 1.4 mm.; 4 whorls. [Cotypes, Nev/ 

 York State College of Forestry, No, 1048b.] Off Short 

 Point in 8^/2 feet, mud bottom. 



Amnicola clarkei Pilsbry. 



The shell is narrowly umbilicate, conic, a little obtuse at 

 the apex, corneous, nearly smooth. The whorls are very 

 convex, separated by a deep suture, the last whorl tubular. 

 The aperture is distinctly oblique, almost circular, the upper 

 end rounded, but a trifle more narrowly so than the base. It 

 projects but little beyond the preceding whorl laterally. The 

 peristome is thin, continuous scarcely or barely in contact 

 with the preceding whorl above. 



Length 3.1, diam. 1.9, length aperture i.i mm.; 5 whorls (type) 



Length 2.8, diam. 1.6, aperture 0.85 mm. 



[Cotypes, New York State College of Forestry, No. 82od] 



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. hakeriana 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 algse; also in Lower 

 South Bay, etc. Collected by Mr. F. C. Baker. 



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

 tor of the Museum of the State of New York. 



