230 TRANSACTIONS OF THE WAGNER FREE 



tortuous, with a strong siphonal fasciole ; aperture elongated ; outer lip flexu- 

 ous, a little reflected, compressed near the suture, receding near the periphery 

 and produced anteriorly, internally Urate with rather distant, sharp, sometimes 

 duplicate elevated threads ; throat with an obscure subsutural ridge and at 

 maturity a few short, strong, irregular lir^ near the suture on the inner lip 

 and on the pillar at the canal ; inner lip wide, callous, smooth, except for the 

 lirse ; pillar twisted, with two deep grooves behind its elevated edge, so that 

 there are practically three plaits, which in mature specimens are nearly hidden 

 behind the pillar. Lon. of two specimens, A and B, A 120, B 115 mm.; 

 max. lat., A 55, B 52 mm. Lon. of aperture and canal, A 72, B 71 mm. 

 Another in Coll. Willcox measures 140 mm. long by 62 mm. wide. 



This fine shell has been badly figured by Emmons, and it was thought 

 well to refigure it, as it has been so little known that a broad variety of it has 

 been described by Conrad under the new name of snbtenia. 



F. Sparrowi has been poorly described by Emmons, and it is necessary 

 to devote some study to his description in order to understand exactly what 

 his phrases mean. The typical Sparroivi differs from the broad specimens 

 of F. acuta in the character of the spiral sculpture, which is sparser, not 

 carinate, with rounded or flat-topped, rather widely separated, elevated 

 threads, with the small intercalary thread often wanting. The aperture is 

 flexuous, the outer lip recedes toward the periphery, and then proceeds for- 

 ward nearly parallel with the axis, so that the incremental lines cross the axis 

 obliquely behind the periphery and axially in front of it, the periphery being 

 marked by one or more stronger spirals, behind which the whorl is flattened 

 toward the suture. The whorls are crossed by ten or twelve rounded, rather 

 prominent, slightly flexuous ribs, which become obsolete toward the suture, 

 and on the last whorl are well marked only toward the periphery. The inter- 

 spaces of the spirals are more or less channelled, while in acuta the spirals 

 are keeled or sharp-edged, and slope evenly toward the middle of the inter- 

 spaces from the keel. In acjita there are no well-defined ribs on the body- 

 whorl, the shell is less flattened in front of the suture, and has a longer and 

 more twisted canal, being, on the whole, a longer and more slender shell, 

 with more crowded sculpture and less regular ribbing. These differences are, 

 however, all of degree and not of kind, and a sufficient amount of material 

 might show the extremes to be connected by intermediate specimens, as with 

 the varieties of F. gigantea. Specimens of Sparroivi corresponding to the 

 above description have been found at Alum Bluff, on the Chattahoochee River, 

 Fla. (Burns), at Faison, Duplin Co., N. C. (Willcox), and at Purdy's 

 marl-bed, Bladen Co., N. C. Most of the specimens from the vicinity of the 

 Natural Well, Duplin Co., are unmistakable F. acuta, though often quite as 

 wide as the typical Sparrowi. 



The same beds afforded specimens of F. gigantea, not apparently 

 separable from recent specipiens by any important or even fairly discernible 



