178 TRANS. WAGNER FREE INST. SCIENCE, PHILA. 



The fossils have the size of the living piigilis of the same waters, and are 

 partly spiny and partly smooth. The S.gracilior is a member of this stock, 

 ancestors of which evidently migrated from the Antillean region before the 

 communication between the two oceans was closed. It preserves the small 

 size and rufous tint of the Antillean type, and though it reaches quite as far 

 north on the Pacific as the latitude of Florida, shows no disposition to take 

 on the brown ornamentation of the Floridian forms of pvgilis. Another link 

 between the S. proxhmis and the recent 5. gracilior is afforded by the smooth 

 outer lip common to both. The liration of the outer lip I have not seen at 

 all in the Miocene shells, it is occasional but rare and exceptional with the 

 Pliocene specimens, while the living shells when fully adult always exhibit 

 traces and generally strong lirse. The Pliocene alaitis are as large as the re- 

 cent ones, and so are the spiny specimens. In the Caloosahatchie beds the 

 specimens appear at all levels, but, like other shallow-water species, are more 

 abundant near the top, which was deposited in very shallow water. 



Strombus Leidyi Heilprin. 

 Strombus Leidyi Heilp., Trans. Wagner Inst. i. pp. 85, 103, pis. 6, 7, 18S7. 



Coiwi bis sp. (princeps) Heilp. MS., Proc. Acad. Nat. Sci. Phil. 1886, pp. 12, 227, olivi. Am. 

 Nat. XX. p. 754, Aug. 1886; young shell. (Not described.) 



Pliocene of the Caloosahatchie beds. 



This species resembles S. inermis and 6". integer of the recent fauna, to 

 which it is evidently related, but the young shells are entirely distinct, and 

 whatever be the fate of the group of forms arrayed under the head of costatiis, 

 integer, etc., there can be no doubt of the distinctness of this one. The very 

 young shell has a small, smooth nucleus of about two whorls, followed by 

 about twelve sculptured whorls. Normally the earlier ones are finely, spirally 

 threaded all over, each whorl with four little-prominent varices, between 

 which are several narrow riblets still less elevated. The whorls appear closely 

 appressed at the suture, and flattened or even a little excavated in the adoles- 

 cent shell. In the latter it may be seen that there is really a deep, narrow 

 channel at the suture ; the body-whorl is sharply, spirally sulcate, with wider, 

 flat interspaces, and there is a broad band of sharp, subsutural lirations, fine 

 and close together like a skein of coarse silk, wound around the body of the 

 shell. The shell in this state is remarkably like a Conorbis, and if supposed 

 to be adult would be pronounced to belong to that genus by any conchologist. 

 The pillar is remarkably straight for a stromb, which enhances the deception. 

 The height and acuteness of the spire vary a good deal, as in all stronibs, 

 and so does the nodulation on the back. I have examined a good many speci- 

 mens of the variety integer, which is common on the Bahamas, and even 

 reaches some of the Florida Keys. It is closely related to inermis, and 

 neither has any subsutural lirse. The variety costatus or accipitrinus, how- 

 ever, shows a narrow band, but much less marked than in the fossil, while the 

 aperture is of an entirely different shape. 



