Width. 





4.50 mill. 



type. 



2.50 " 



cotype. 



2.50 " 



cotype. 



LYMNv£ID,E OF NORTH AMERICA. 107 



are somewhat malleated and in a few cases there are a few obscure 

 revolving ridges ; whorls 7, convex, very slowly increasing in size, the 

 body whorl slightly compressed laterally in the majority of specimens; 

 nucleus reddish, flattened; spire very acutely conical, \y 2 times the 

 length of the aperture ; sutures deeply impressed ; aperture elongate- 

 ovate, continuous ; outer lip thin on the edge, but thickened within by 

 a well marked, heavy varix ; inner lip reflected over but not closing 

 the umbilicus, leaving a well-marked chink; parietal callus rather 

 heavy and tightly appressed; the columella is covered by a distinct 

 fold, somewhat resembling a tooth. 



Aperture 

 Length. Width. Length. 



19.00 7.00 7.00 



15.10 6.25 6.00 



13.50 5.50 5.50 



Types: Smithsonian Institution, 5 specimens, No. 162721. 



Cotypes : Two specimens Chicago Acad. Sci., No. 23875. 



Horizon : Pleistocene marls. 



Locality : Marl Lake, Anticosti Island, Canada. 



Remarks: Anticostiana is a very distinct species, exactly com- 

 parable with no other species of American Lymnseid. It has a faint 

 resemblance to some forms of desidiosa and also to elongated forms of 

 obrussa. It is, however, distinct from both these species. It is probably 

 an extinct species, as nothing like it has been seen in the multitude of 

 specimens examined during the preparation of this monograph. This 

 is undoubtedly the shell mentioned by Bell (op. cit.) as "the most 

 abundant species in the shell marl from Marl Lake, Anticosti." 



Galba baked (Walker). Plate IV, figure C. 



Lymncea bakeri Walker, Nautilus, XXII, p. 18, pi. ii, figs. 11-12, June, 1908. 



"Shell: Slender, elongate, perforate; whorls 5; spire elongated, 

 turreted ; apex acute ; body whorl narrow, elongated, compressed below ; 

 suture deeply impressed ; lines of growth fine and regular with fine sub- 

 obsolete, revolving, spiral lines ; aperture narrow, elongated, within the 

 flare of the lip, the sides are nearly parallel, and about equally rounded 

 above and below ; lip thin, sharp, suddenly and broadly expanded, sub- 

 reflected, continuous, not appressed to the parietal wall, and roundly 

 reflected over the perforation, columella straight, without a fold ; axis 

 round and smooth. 



"Alt. 16.5, diam. 7.5, length ap. 8.5,- width 4.5 mm." (Walker). 



Type: Coll. Bryant Walker, No. 9353. 



Horizon : Pleistocene Marls of Michigan. 



Locality: Pine Lake, Charlevoix County, Michigan. 



