244 TRANSACTIONS OF THE WAGNER FREE 



the recent shell. T. engonatiis is with little doubt the Pliocene ancestor of the 

 recent obeliscus. The specimen figured is not quite adult, but shows the sculpt- 

 ure better than an older specimen. The limy coat characteristic of the group 

 is so easily detached that few of the shells have more than small patches of it 

 remaining. 



Genus RAP ANA Schumacher. 



Bapana tampaensis Dall var. ? 



Plate 20, figure 14. 



Part I. p. 153, 1S90. 



No additional material certainly belonging to this species has been re- 

 ceived, but a shell which in some aspects appears almost identical with the 

 Tampa fossils was collected by Mr. G. D. Harris, of the U. S. Geol. Survey, 

 near Church Hill, Queen Anne Co., Md. 



A specimen apparently of the same species is one of two seemingly dis- 

 tinct forms in the collection of the Academy of Natural Sciences at Philadel- 

 phia, labelled Neptnnea bilix Conrad. This fossil was described by Conrad 

 under the name of Biiccmum bilix in 1843 (Proc. Ac. Nat. Sci. i. p. 308), and 

 subsequently {pp. cit. for 1862, p. 562) referred to the Nassidce under the 

 name of Tritia bilix. That one of the two specimens above referred to which 

 agrees with the characters of most of Conrad's other Tritias is probably a 

 Ptycho salpinx, and may preferably be allowed to retain his specific name, since 

 his description is too brief to identify the genus or species by, and it would 

 seem never to have been figured. The other, of which a figure is given here- 

 with, appears to be a Rapana, with somewhat the form of Clirysodomiis. The 

 few specimens obtained appear extremely variable ; some of them show 

 rounded whorls and a channelled suture ; others like the one figured have a 

 coarse rib near the suture, and no well-defined channel. All differ from the 

 types of tampaensis in having a comparatively insignificant umbilical chink 

 and slender anterior extremity. But the variations of the Purpurida within 

 a single species are well known to be extreme, and, until a perfect speci- 

 men of the Floridian fossil comes to hand, I am disposed to refer both to 

 a single species in spite of the differences above mentioned. 



Family SCALID.(E (supplementary). 

 Genus SCALA Humphrey. 

 Subgenus Opalia Adams. 

 Section Pliciscala De Boury. 

 Scala (Opalia) De-Bouryi Dall. 

 Plate 20, figure 13. 

 Part i. p. 158, 1890. 

 A figure of this fine species is now provided. 



