26- Calvix Goodrich 



shining, the bands more obscure. A mottled effect as in flammata and zehra 

 mutations is rather rare, as is also the occasions when the coloring matter 

 of the bands has spread throughout the shell. 



Fifteen arrangements of bands were noted in this study — the arrange- 

 ment of four equidistant bands prevailing. Nine arrangements were modi- 

 fications of this fonnula, these being exceedingly uncommon and so indicat- 

 ing that they represent merely individual variation or aberration. Few shells 

 W'ithout bands and few with the bands broken into squares or oblongs occur 

 in the upper parts of this species' range. Below Lock 4, broken bands be- 

 come predominant. In nearly every lot one to several shells occur which 

 have bands upon the epidermis that do not show in the aperture. 



The nuclear shell of tacniata is smooth, loosely-coiled, having about 

 one and one-half whorls. Of seven juveniles from Ten Island Shoals, the 

 columellae of six were white or pink and one was purple. All these shells 

 Avere four-banded, the peristome flaring; no angulation occured at the peri- 

 phery. 



The operculum is elongate, reddish-brown, with growth lines fine to 

 coarse, closely set together. The left margin is firm, very slight^ rounded. 

 Apex rounded. The right margin is thin, often broken and uneven, curved. 

 The basal margin is broadly rounded, frequently worn or ragged. In ten op- 

 ercula examined, the polar point of five was upon or close to the left 

 margin. In the other half, it was nearly in the center of the basal margin. 

 This shifting of position was due to wearing. The nucleus is very small, in- 

 dented, crater-like. Such spiral development as can be made out in most of 

 the opercula is closely confined to a very small space n^r the base, and 

 in only one specimen examined was it possible to trace the full three whorls 

 common to the operculum of species of this genus. The area of attachment 

 is elongate, oval. In a small form of taeniata which Mr. Smith separated 

 from collections at Ten Island, Three Island and Butting Ram shoals, the 

 chief differentiation is an elongated, narrow operculum with a straight left 

 margin. 



Measurements of shells: 

 Altitude Diameter 



Clarence Shoals, St. Clair County 

 Lonigan " " " " 



Ten Island Shoals, St. Clair County 



Lock 2, St. Clair County 

 Truss Shoals, St. Clair County 

 Three Island Shoals, Talladega County 

 Ft. William Shoals, " " 



Peckcrwood Shoals, " " 



Weduska Shoals, Shelby County 



The Bar, Chilton County 



Wetumpka, Elmore County 



