31g THE CHICAGO ACADEMY OF SCIENCES. 



was drained ages ago by the cutting down of the barrier." (Hender- 

 son, Colorado. ) 



In a still, swampy pool, protected from the waves of Lake Huron. 

 (Nason, Alpena, Mich.) 



"Taken from a pond near Bitter Root River. Quite abundant, 

 several hundred specimens taken. Also taken in abundance in standing 

 and quiet waters in the creeks on Flathead Indian reservation. At 

 the upper end of Flathead Lake there is a great deal of marshy country 

 tributary to the lake and to Flathead River. In the lowland bordering 

 on the lake, which had been overflowed and later dried off, large 

 quantities of dead shells were observed. Indeed, the shells were so 

 abundant one could not walk without mashing large numbers. In 

 still other places the shells were yet alive in the sloughs, in great abun- 

 dance. Along the Bitter Root River the shells were living in the same 

 waters with Aplexa hypnorum." . (Elrod, Montana.) 



"A few days ago, while collecting iresh-water shells in the dry 

 bed of a pond near Alum Rock Park, San Jose, the author found 

 several live specimens of a form of Lymncea palustris (Miiller) lying 

 on the dry mud surface with the aperture sealed down by a thick dried 

 mucus and withdrawn into their shells half a whorl. The pond usu- 

 ally contains water at least half the year, but on account of the dry 

 spring has contained none since April 1st at least. The bed is thinly 

 covered with tall tulas, so that the shells were not in the direct rays 

 of the sun. This form is the only one which occurs in the lake, and 

 dead shells up to barely mature are abundant, and some larger." 

 (Hannibal, California.) 



"Young, hatched in August, in a small aquarium, were fully grown 

 by midwinter." (Sterki, Ohio.) 



Quinn River crossing, Humboldt County, Nevada, altitude 4100 

 feet. In pools, Yellowstone Park. (Berry.) 



REMARKS: Palustris is one of the commonest and most variable 

 of the Lymnseas, being equaled in this respect only by Galba obrussa. 

 The large, more or less corpulent shell, with its coarse, generally mal- 

 leated sculpture and heavy columella plait, will easily distinguish it 

 from related species. The whorls in typical palustris are always well 

 rounded, especially the body whorl, which may be quite robust. The 

 aperture and spire are generally equal in length and the whorls are 

 much wider than high, a character which will help to separate the 

 narrow forms from reflcxa and elodes. The principal variation is in 

 the form of the spire, which in some specimens is long and narrow 

 while in others it is short and corpulent. This variation does not seem 



