LYMNiEIM: OF NORTH AMERICA. 401 



some specimens and coarser in others, crossed by very indistinct 

 spiral impressed lines; in old specimens the shell becomes very rough 

 and eaten away by the excess of carbon dioxide in the water; whorls 

 2> x /2 in perfect specimens, but generally only 2 to 2^ remain intact, 

 the tip of the spire being decollated ; the whorls are rather flat sided 

 on the spire, the body whorl alone being ventricose and sometimes 

 roundly sloping above the periphery ; apex light horn color, small, 

 rounded ; spire very short, broadly conic, generally decollated ; sutures 

 tightly appressed, in some specimens distinctly impressed; aperture 

 large, ovate, occupying two-thirds the length of the shell, in old speci- 

 mens distinctly campanulate; peristome thin, acute; the outer lip is 

 inclined to thicken within the aperture and a transverse varix edged 

 with reddish brown is sometimes formed; inner lip reflected over the 

 parietal wall and umbilicus, tightly closing the latter ; the axis is 

 slightly twisted and there is a well marked fold. 



Length. 



Breadth. 

















15.00 



12.50 mill. 



(Mighels .6 by .5 inch.) 









15.00 



10.50 



" 



Tryon. 

















Aperture length. 



Brea 



dth. 









12.00 



8.00 





9.00 



5.50 



mill. 



Walker, received 

 ghels. 



from 



Mi- 



12.25 



8.00 





9.00 



5.50 





Walker, received 

 ghels. 



from 



Mi- 



11.25 



7.75 





8.00 



5.00 





Walker, received 

 ghels. 



from 



Mi- 



9.75 



7.00 





7.00 



4.50 





Walker, received 

 ghels. 



from 



Mi- 



11.00 



7.50 





8.00 



5.00 



" 



Walker (J. G. An 



thony' 



). 



11.75 



8.00 





8.25 



5.00 



" 



Phil. Acad. Sci. 







12.00 



8.50 





8.50 



4.50 



" 



Smith. Inst. 







14.00 



11.50 





9.25 



7.00 



" 



" " 







17.00 



11.25 





12.50 



6.50 



" 



Bost. Soc. N. H. 







15.25 



11.00 





11.50 



6.25 



" 



a it a 







Types : Destroyed in Portland fire of 1866. Specimens received 

 from Mighels are in the collection of the Academy of Natural Sci- 

 ences, Philadelphia, No. 58703 ; in the Boston Society of Natural 

 History, No. 24192; the Chicago Academy of Sciences, No. 23811 and 

 in the collection of Mr. Bryant Walker. 



Type Locality : Lake Winnecook, Unity, Waldo Co., Maine. 



Animal : "Dingy mouse-color, with a slight tinge of purple ; 

 covered with numerous microscopic, elongated white spots on every 

 visible part of the surface, including the mouth and tentacula; foot 

 of a chocolate color, rather broad, length rather greater than the 

 aperture." ( Mighels ) . 



