446 TRANSACTIONS OF THE WAGNER FREE 



The denticulations of the posterior orifice are very variable in strength, 

 and there are sometimes six instead of four. The recent shell has a yellowish 

 silky lustre, but never seems to have the brilliant polish of some of the other 

 species. 



Cadulus floridanus n. s. 

 Plate 23, figure 26. 



Chesapeake Miocene of the upper bed at Alum Bluff, Appalachicola 

 River, Florida, Burns. 



Shell of moderate size, polished, little arched, section behind the cingulum 

 circular; in front of it, including the mature aperture, slightly dorso-ventrally 

 compressed ; cingulum not differentiated, equator slightly anterior to the mid- 

 length of the shell ; margin of the circular posterior orifice simple, or very 

 slightly undulated ; anterior orifice of the adult oval. Lon. of shell lo.omm. ; 

 max. diam. 2.0 ; dorso-ventral diam. of anterior end i.o; of posterior end 

 0.6 mm. 



Compared with C. pandionis, this species is longer, straighter, less 

 attenuated anteriorly and less abruptly tapered from the equator, while the 

 different form of the aperture has alreadj' been referred to. It varies in length 

 somewhat, but on the whole the specimens are very uniform. 



Cadulus floridanus var. Burnsii Dall. 



Chesapeake Miocene of the upper bed at Alum Bluff, Frank Burns. 



Shell smaller, but exactly resembling the type in form, except that the 

 equator is slightly more emphasized. Lon. 7.0; max. diam. 1.5; anterior 

 aperture 0.8; posterior aperture 0.5 mm. 



If it were not that there seems to be a gap in the matter of size between 

 this form and the type which my specimens do not fully bridge over, I should 

 hardly have felt it necessary to name it. 



