The Spire Shells and Flood Shells 



Haliotis, .the Abalone, on the CaUfornia coast. It is a simple 

 conical shell i inch long. Whether the Abalone is conscious of 

 the burden it carries, I cannot say. Probably it counts these 

 passengers as a part of its scheme of protective coloration. If 

 so, then the little haliotis-lover pays for his lodging, and the 

 migrations of the host help to keep the stationary guest mollusks 

 supplied with food. 



Genus AMNICOLA, Gld. and Hald. 



Shell small, short, ovate or globose, thin, smooth; apex not 

 acute; aperture broadly ovate, not oblique; lip thin, sharp; 

 not projecting below; operculum horny, spiral. Foot short, 

 broad, rounded behind; tentacles blunt; snout short; egg cases 

 pod-like, short, one egg in each. A fresh-water snail of North 

 America. Species few. 



A. limosa, Say, the type, is dark horn-coloured, often en- 

 crusted with black, as it is found in muddy stream borders; the 

 body is white, marked with brown above. Say found them 

 numerous on the banks of Schuylkill and Delaware rivers, 

 between high and low tides. Length, /t inch. 



Habitat. — Hudson Bay region to Wisconsin and Virginia. 



Genus FLUMINICOLA, Stimps. 



Shell obliquely ovate, thick, smooth, spire blunt; inner lip 

 flat and callous, outer lip spreading, especially below; operculum 

 horny. Egg cases lens-shaped, containing many eggs. Found 

 in fresh water in Oregon and California. 



Nuttall's Flood Shell (F. Nuttalliana, Lea) may be distin- 

 guished from neighbouring genera by its solid shell and sub-spiral 

 operculum. It has been given five other generic names. The 

 rivers of the two western states mentioned furnish plenty of 

 specimens. Length, f inch. 



A green species, F. virens, Lea, somewhat slender and 

 oblique, but very thick, and a very stout, almost spherical one. 

 F, fusca, Hald., reddish, with white lip, and the size of a pea, 

 inhabits Oregon streams. 



Genus POMATIOPSIS, Tryon. 



Shell small, thin, elongated, of few very much rounded 

 whorls; aperture round, lip continuous, extended or reflected; 



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