138 R. E. Qall — Geographic and Hypsometric 



the Black Warrior at Tuscaloosa. Unlike the .northern shell 

 many specimens were obtained in certain small creeks but 

 always under conditions similar to those which obtained in the 

 Cahaba. 



Tulotoma magnified Conrad will include all the forms de- 

 scribed by Dr. Isaac Lea except the single one hereinafter 

 mentioned. It is confined to a single stream in Alabama and 

 has been obtained in but two or three localities in that river. 

 From Wetumpka, Alabama, to a point just below Claiborne 

 constitutes the extreme range of the genus and its two species. 

 At Wetumpka it was found in wonderful abundance attached 

 to the under surface of fiat rocks in the most swiftly flowing 

 portions of the river just above the government works. Its 

 discovery was quite an accident and several days had been 

 spent in its search when a fall revealed its whereabouts. 



The second species of the genus Tulotoma cooscensis Lea 

 is found only at Wetumpka and in similar situations. The 

 very young and perfect shells are ornamented with minute 

 hairs arranged in regular lines. The whorls are always much 

 more convex than those of the associated form and the aper- 

 ture is never angulated. All the other names are synonyms of 

 these two ; they chiefly apply to Conrad's form. 



The widest distribution of the genus Vivipara is seen in 

 the form Vivipara contectoides W. G. Binney. This occurs 

 all over the Mississippi valley from Iowa to southern Missouri 

 and eastwards to central Ohio. Southwards it extends to 

 Mississippi, Alabama, Georgia and Florida, being abundant in 

 all these States. East of the Appalachians its northernmost 

 range is in South Carolina. But in central New York is a 

 large area over which it has become distributed owing to cer- 

 tain favoring conditions. Dr. James Lewis colonized a num- 

 ber received from Illinois in the Erie Canal and from these 

 have arisen a most wonderful number of descendants. The 

 Erie Canal from Utica to Troy is alive with them ; many have 

 escaped into the Mohawk river and have there found a con- 

 genial home. Aside from this rapidly disseminating colony, 

 however, no forms occur naturally east of the Appalachians in 

 the northern States. In the southeastern States other forms 

 have been based upon this species and these under the names 

 of Vivipara waltoni Tryon and Vivipara georgiana Lea have 

 been considered in stating the limits of this form. The 

 southernmost locality west of the Mississippi river is Fourche 

 Creek, Pulaski county, near Little Rock. 



Vivipara intertexta Say does not occur outside of the Mis- 

 sissippi valley except in certain portions of Louisiana. It was 

 originally described from near New Orleans whence it ranges 

 northwards to White Bear Lake and Winona, Minnesota. In 



