112 THE NAUTILUS. 



the fully matured shell, from the Tennessee river at Florence, Ala., 

 collected by Mr. A. A. Hinkley, there seems to be no doubt but that 

 the changes in growth of the two series have been identical. 



The minute young in the Florence series have the apical whorls 

 carinate and the body-whorl bicarinate. I have no difficulty in 

 identifying this form with Lea's cincinnatiensis. The type had four 

 whorls and measured 4 mm. in height by 3.5 in diameter. As a 

 standard for comparison I have selected an individual of exactly 

 these dimensions (Fig. 1); although most of the specimens of that 

 diameter are more depressed, the altitude and width being substan- 

 tially the same. 



This specimen agrees with the original diagnosis in every par- 

 ticular with one exception. Lea states that the type had three 

 bands and that the two carinas were colored. Whether the three 

 bands included the two carinal bands, he does not say. All of my 

 specimens, with one exception, exhibit four bands within the aper- 

 ture. Two are carinal, one is between the upper carina and the 

 suture, and the fourth between the lower carina and the umbilical 

 depression. These bands are continuous or broken into spots, and 

 sometimes the upper and lower pairs are more or less confluent. 

 The exception has only the upper pair of bands, the lower carina 

 and basal area being uncolored. I do not regard the variation in 

 banding of any material importance and, therefore, have no 

 hesitation in proceeding on the assumption that these bicarinate 

 individuals are the cincinnatiensis of Lea. As shown by Fig. 1, the 

 typical form of A. cincinnatiensis has four whorls ; the spire is 

 acutely conical, its whorls flattened and bounded below by the pro- 

 jecting carina, the suture of the succeeding whorls being on the 

 under side of the carina and slightly within the outer edge ; the 

 body whorl is strongly bicarinate, flattened above the superior 

 carina, concave between the carina? and with the basal arc area 

 flattened and very oblique. The shell is rather translucent, light 

 horn-color, more or less tinged with green; apex is red, lighter than 

 the supracarinal band, and the bands dark reddish-brown ; the 

 superior band is broad and on the apical whorls fills nearly the en- 

 tile space between the carina and the suture, so that the whorls 

 appear wholly dark colored ; the basal band is broad, the color ex- 

 tending to same degree over the entire umbilical area; the columella 

 is more or less tinged with purple. The aperture is large " rounded," 



