LYMN^EID^E OF NORTH AMERICA. 109 



Locality: Nashotah, Waukesha County, Wisconsin. 



Remarks : Nashotahensis was at first thought to be a form of 

 Galba daniclsi; it differs markedly from that species, however, in sev- 

 eral particulars — the spire is broader and not so acute, the body whorl 

 is larger and inclined to be gibbous, there is a conspicuous umbilical 

 chink {daniclsi is usually imperforate) and the columella is not notice- 

 ably plicate. In nashotahensis the aperture is elongate ovate, narrowed 

 above and broadened below where it is often patulous. The upper 

 whorls are strongly suggestive of Galba reflexa, the penultimate whorl 

 having the swollen appearance so characteristic of reflexa. 



Young specimens somewhat resemble Galba catascopium, differing 

 in being narrower, with a more elongate aperture, longer and less 

 rounded whorls and a less distinctly plicate columella. There is also 

 an umbilical chink which is usually absent in catascopium. Certain 

 specimens from the marl beds at Kegobic, Michigan, seem referable 

 to this species. Nashotahensis was probably contemporaneous with one 

 of the glacial stages of the Great Lakes. 



Like Walker's Galba bakeri from Michigan, nashotahensis is an 

 extinct species peculiar to the marl deposits. The specimens were se- 

 cured by Mr. F. M. Woodruff. 



DOUBTFUL LYMN^AS AND SPECIES WRONGLY REFERRED TO THIS FAMILY. 



There have been a number of references to the occurrence of 

 Lymncea in Mesozoic and Tertiary strata, where the determinations ap- 

 parently have never been made. There are also several cases in which 

 the species, on more careful examination with additional material, 

 have been found to belong. to another family of mollusks. These are 

 listed below. 



Lymncea Sp. 



Limncea? Upper Kanab, Utah; White, Rep. Geol. Uinta Mts., p. 100, 1876. 



Lymnaea Sp. 



Limncea sp.? Pliocene, Cache Valley; Peale, An. Rep. U. S. Geol. & Geog. 

 Surv. Terr., XI, p. 640, 1879 (possibly the same as Meek's Kingi). 



Lymnaea Sp. 



Limncea sp., Darton, Bull. Geol. Soc. Amer., XIX, p. 446, 190S. — Darton 

 and Siebenthal, Bull. U. S. Geol. Surv., 364, p. 30, 1909. 



Horizon : Morrison, Comanchean Period. 



Locality: West of Downey Lakes, in the N. W. %, Sec. 15, T. 

 13 N., R. 75 W., Southern Wyoming. 



Lymnaea Sp. 



Acella sp. Whiteaves, Con. Can. Pal., I, p. 13, 1885. 



"A few fragments of an Acella were collected by Dr. G. M. Daw- 

 son in 1874 and 1881. Dr. C. A. White, to whom these specimens 



