INSTITUTE OF SCIENCE, PHILADELPHIA. 77 



the sutural line, forming a prominent sinus, and crossed on its inner face 

 by numerous parallel, raised (revolving) lines ; columella conspicuously 

 arched or flexed, with some five to seven oblique plaits, the lower two of 

 which are much more prominent than the others ; no umbilicus ; general 

 surface of shell smooth. 



Length, two and half inches; width across the centre, somewhat more 

 than an inch and a third. 



Caloosahatchie, in the banks below Fort Thompson. 



This species appears at first sight veiy much like the Eocene M. 

 pvnda, but may be readily distinguished by its greater ventricosity, the 

 convexity of the whorls, and the absence of the sutural carination (or 

 more properly, sub-angulation). The columellar plaits are also con- 

 siderably more prominent in the Florida form. 



As far as I am aware these are the only two species that can be 

 properly included in the genus, which appears, consequently, to be ex- 

 tinct. Whether or not the modern Lagena, which so closely resembles 

 it, is immediately related, remains to be determined. ( 



Voluta Floridana, nov. sp. Fig. 8. 



Shell fusiform-ovate, smooth, except two or three of the terminal 

 whorls of the spire, which are longitudinally ribbed, and cancellated by 

 a number of delicate revolving lines ; spire elevated, of about six volu- 

 tions, terminating in a slightly papillated apex ; whorls convex, hollowed 

 above the middle, the depression in the upper whorls forming a sub- 

 sutural band or carination. 



Body-whorl smooth, about four-fifths the length of the shell, covered 

 with delicate revolving lines, which become obsolete with age ; aperture 

 of nearly equal length, truncated at base ; columellar surface with four 

 prominent oblique folds, the upper of which is generally the longest. 



Length of longest specimen somewhat less than six inches ; greatest 

 width, 2.3 inches. 



Abundant in the banks of the Caloosahatchie below Fort Thompson. 



I have little hesitation in affirming that this shell is the probable 

 ancestor of the recent Voluta Juiwnia of Chemnitz which is occasion- 

 ally obtained along the western keys (Egmont Key, etc.) and in the 

 deeper waters of some of the inner bays. So close is the resemblance 

 between the two species that at first sight there would appear to be not 

 even the most insignificant characters by which to separate them. Al- 

 though the fossils are in nearly all cases badly worn, yet in some the 

 indications of color are still fairly preserved, which lead me to conclude 

 that the general coloration of the shell was much as in the recent form. 

 About the only character of any significance that I can indicate which 

 might serve to distinguish the two species lies in the formation of the 



r&SS**. 



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