366, - TRANSACTIONS OF THE WAGNER FREE 



Another Eocene species which should probably be referred to this sub- 

 genus is N. magno-umbilicata Lea, a small species with a deep suture, usually 

 marked above with sharp radiating wrinkles, and having a rather wide cari- 

 nated and excavated umbilicus marked with numerous sharp, elevated, fine 

 spiral threads, which, in the young, serrate the umbilical edge of the pillar, 

 but in the fully grown become much more feeble. It is known from the 

 Claiborne sands and Wood's Bluff, Ala. It is the N. bisulcata of Heilprin, 

 and has been referred by De Gregorio to N. Noes Orbigny as a variety, though 

 N. No(Z wdiS described in 1850 and N. magno-iunbilicata in 1833. I am unable 

 to decide, for want of sufficient foreign material, whether the European fossil 

 is really identical with that from Claiborne or not. 



Subgenus Stigmaulax Morch. 



This group is not known to be represented in our older Miocene, but 

 appears in that of Bowden, Jamaica, and of Haiti, where the N. (5.) sulcata 

 Born is rather common, not differing in any respect from recent specimens. 

 It is figured by Guppy (Quart. Journ. Geol. Soc. xxii. p. 290, pi. xviii. figs. 

 14, 15, 1866). 



Subgenus Cryptonatica Dall. 



Natica (Cryptonatica) floridana n. s. 



Plate 17, figure 5. 



Older Miocene of the Chipola beds, Calhoun Co., Florida, and of the 

 Orthaulax bed, Tampa Bay, Florida, Willcox, Dall and Burns. 



Shell small, compact, the males with more sloping, the females with four 

 or five more rounded, whorls; suture distinct, not channelled; the whorl near 

 it marked by lines of growth often forming slightly elevated wrinkles ; the 

 remainder of the surface smooth, more or less polished; base rounded or in 

 the males slightly flattened, with a tendency to an obtuse carina at the periph- 

 ery and also on the margin of the umbilicus; umbilicus rather wide, almost 

 filled with a semilunar callus, smooth and flattish on its outer surface, rounding 

 into a shallow chink on the left side of the umbilicus or, especially in the 

 young, sometimes practically filling it ; callus on the body well developed, 

 with a short, shallow subsutural groove in the adult; aperture with the outer 

 lip thin-edged, half-moon-shaped, rounding evenly into the pillar. Alt. of 

 adult shell 16.5 ; diam. 17.0 mm. 



This species probably belongs to Ctyptonatica, although the operculum 

 has not turned up. The specimen figured from Ballast Point, though perfect, 

 is quite young; fully adult specimens from Chipola were only obtained later. 

 It is remarkable for the difference (probably sexual) between the rounded and 

 the flattened specimens, all gradations between the two being shown by the 

 series before me. 



