INSTITUTE OF SCIENCE, PHILADELPHIA. 275 



Bittiuni (Styliferina ?) priscum Dall. 

 Plate ir, figure 6. 

 Part I. p. 1S9, pi. .\i. fig. 6, 1890. 



Older Miocene of the Orthaulax bed at Tampa, Florida, Shepard and 

 Dall. 



Shell small, slender, the specimens decollate ; the remainder shows 

 seven rounded whorls with a distinct suture, two or three raised spirals on 

 the whorls and three more on the base. These are crossed by a variable 

 number of slightly arched riblets, which are frequently nodulous at the inter- 

 sections ; in the perfect state these nodules were sometimes very prominent ; 

 aperture short, rounded, with an obsolete canal, reflected inner lip with a chink 

 behind it; a short and obscure pillar and a short, thin, sigmoid outer lip 

 without lirse. Lon. of shell figured 7.0 ; max. diam. 2.75 mm. 



This species is represented only by siliceous pseudomorphs, which are 

 not very satisfactory in so small a shell ; but from the fragments collected it 

 seems different from any of the Chipola species. The specimen figured was 

 defective in the region of the pillar ; subsequently collected specimens give 

 the characters of the canal and outer lip. It seems to have run through a 

 range of sculpture-variation very similar to that exhibited by the species 

 previously described. It would seem to have been in the ancestral line from 

 such species as B. boiplex and B. Adainsi Dall. 



Bittium (Styliferina) boiplex n. s. 

 Plate 21, figure 14. 



Chipola older Miocene, Burns. 



Shell small, slender, acutely pointed, strongly sculptured, with two 

 minute, smooth and ten subsequent rounded whorls ; earlier whorls with only 

 spiral sculpture, which later becomes sharp, elevated threads alternating in 

 strength, with three strong spirals on the base, on the posterior of which the 

 distinct, appressed suture is applied ; the spiral sculpture crosses numerous 

 concavely-arched riblets, which may be strong or obsolete; there are also 

 numerous well-marked, rounded varices irregularly distributed both in posi- 

 tion and number ; the whorls are well rounded, the aperture ovate, with 

 hardly a trace of canal ; a short, arched pillar, thin, simple outer lip, and no 

 lirations in the throat. Lon. of shell 8.5 ; max. diam. 1.75 mm. 



This is one of those forms which unite sections together, showing char- 

 acters of Alaba, Bittium and Styliferina, impartially mixed. It is without 

 doubt of the same stock as B. Adainsi Dall and B. ceritliidioides Dall, and re- 

 calls Bittium Kxneni Meyer, of the Jackson and Shell Bluff Eocene. The 

 latter is, however, much smaller, if Meyer's account be based on a mature 

 individual, and B. Adamsi is also smaller and has a smoother, more regular 

 and somewhat different sculpture. 



B. boiplex varies in slenderness and in the relative strength of the different 



