20 TRANSACTIONS OF THE WAGNER FREE 



and the crests of the ribs a little sharper-edged. The differences are hardly 

 greater than are observable between recent individuals, but for those who 

 insist upon them the fossils may form a variety acila. 



Drillia eburnea Conrad. 



Drillia eburtiea Conrad, Proc. Acad. Nat. Sci. Pliila. XIV. pp. 285, 562, 1863. Smithsonian 

 Checklist Inv. Foss. N. Am. Miocene, p. 21, 1864. (Not of Bivona or Carpenter.) 



Miocene of Maryland (and Virginia ?). Caloosahatchie beds. 



From a specimen of Conrad's unfigured species I have identified two not 

 completely adult specimens from the Caloosahatchie marl. 



The shell resembles Pleurotovia ebiir Reeve, but is more slender, with a 

 less marked anal fasciole and an elevated line in front of the suture. P. ebur- 

 nea Bivona is a Mangilia. Carpenter's species only dates from 1865 and may 

 take the name of D. eburneola Dall. 



Drillia Moseri Dall. 

 Drillia {Cymatosyrinx) Moseri Dall, Rep. Blake Gastr., p. 97, pi. xxxvi. %. 3, Feb., 1889. 



Fossil in the Caloosahatchie beds. Recent, from North Carolina to the 

 Florida Keys, in 3 to 50 fathoms. 



The recent and fossil specimens agree in all respects. I may add that 

 Pleurototna limalula Conrad belongs to this section of the genus Drillia. 



Drillia pagodula Dall. 

 Drillia pagodulaT)a\\, Rep. Blake Gastr., p. 90, pi. xiii. fig. 6, Feb., 1889. 



Caloosahatchie beds. Recent, in Floridian and Antillean waters, in 50 to 

 175 fathoms. 



This species belongs to the group oi PI. ebitr and fiicata Reeve and looks 

 like a very dwarf race of D. Moseri. 



Section Drillia s. s. 

 Drillia ostrearum Stearns. 



Drillia ostrearum Stearns, Proc. Boston Soc. Nat. Hist. XV. p. 22, 1872 ; Dall, Hemphill's 



Shells, p. 328, in Proc. U. S. Nat Mus. VI. 1883. Tryon, Man. VI. p. 197, pi. 34, fig. 79, 



1884. 



Miocene of Chipola, West Florida, and the silex-beds of Ballast Pointy 

 Tampa Bay, Florida; Pliocene, Caloosahatchie beds. Recent, from North 

 Carolina to Florida and Yucatan, between low-water mark and 15 fathoms. 



This species is the recent prototype of a large number of forms extending 

 back to the Eocene. It is frequently difficult to decide what value to assign 

 to mutations occurring in different beds which, among the shells of one 

 locality and geological horizon, would be very generally considered not to rise 

 above varieties of one species. My own impression is that they should not 

 be regarded as of higher grade than subspecies. They would agree very well 

 with the ornithological subspecies, the genetic connection taking the place of 



