INSTITUTE OF SCIENCE, PHILADELPHIA. 3O9 



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beaded, and sometimes both are so. This form was obtained from the Vicks- 

 biirg Eocene at Martin Station, Florida, by Mr. Joseph Willcox, and a cast 

 which may be the same from the nummulitic limestone at Ocala. 



Turritella indenta var. mixta Dall. 



Chipola beds, near Bailey's Ferry, Chipola River, Northwest Florida, 

 Burns. 



This variety has the basal carina double as in well-developed specimens 

 of the type, together with the equatorial spiral sculpture of T. bipertita. The 

 Hnes of growth are periodically sharp and elevated, and the sides of the 

 whorls are comparatively flat. The apical whorls are only faintly sculptured, 

 and the nucleus is very minute. The best-preserved specimen measures 60 

 mm. long and has a maximum diameter of 21.5 mm. These specimens are 

 somewhat more compact than the type, though it is quite variable in this 

 respect. 



Turritella tampse Heilprin. 

 Plate 17, figure 8. 

 Turritella tampce Heilprin, Trans. Wagn. Inst. i. p. 113, pi. 8, fig. 53, 18S7. 



Older Miocene of the Orthaulax bed. Ballast Point, Tampa Bay, Florida, 

 Willcox, Dall and Shepard. 



This form is nearly related to T. indenta, especially the variety martin- 

 ensis. 



The original figure being very poor, the species has been refigured, but 

 the new figure does not show one of the characteristic features of the species 

 — namely, that the entire surface is covered with fine, sharp, but almost micro- 

 scopic spiral threads. In good condition the species may be recognized by 

 the separation at the suture of the later whorls and by the following sculpt- 

 ure : at the base of the whorl two little-elevated primary threads about a 

 millimeter apart, the interspace sharply spirally striated ; behind the posterior 

 primary the whorl is constricted, and covered thence to the suture by about 

 six to eight spiral primaries with narrower, deep interspaces, the whole finely, 

 evenly undulated by fine, regular, sometimes almost imbricated lines of 

 growth. The posterior margin of the suture, when not discontinuous, is 

 slightly more prominent. The base is flattish and spirally striate. The di- 

 mensions are 75 by 16 mm. 



Turritella tampse var. tripartita Dall. 

 Shell with the equatorial constriction marginate on both sides with a 

 primary, and one marginating the suture behind ; the other primaries obsolete, 

 the fine spiral striation remaining. The surface of the whorl is thus divided 

 into three equal striated bands separated by two prominent threads. Two 

 specimens of this variety were found among those collected at Ballast Point. 



