178 SYSTEMATIC PALEONTOLOGY 



the summit of each volution by a revolving line, as deeply impressed as 

 the suture/' Say, 1822. 



This small species is not readily detected until the materials collected 

 in the field have been washed and sorted. The form is very variable, al- 

 though the small variety has alone been found in the Pleistocene of 

 Maryland. 



This species in one of its varietal forms has been recognized in the 

 Eocene of Mississippi. It is not uncommon in the Miocene of Virginia, 

 North Carolina, and Florida, in the Pliocene of the Carolinas and, the 

 Pleistocene from Maryland to Florida. The Eecent range is from Mary- 

 land to Florida, the Bahamas and Venezuela. 



Occurrence. — Talbot Formation. Wailes Bluff near Cornfield Har- 

 bor, St. Mary's County. 



Collections. — Maryland Geological Survey, Johns Hopkins University 

 and IT. S. National Museum. 



Family PLEUROTOMIDAE. 



Genus MANG1LIA Risso. 



Mangilia cerina Kurtz and Stimpson. 



Plate XLII, Figs. 9, 10. 



Pleurotoma cerinum Kurtz and Stimpson, 1851, Proc. Boston Soc. Nat. 



Hist., vol. iv., p. 115. 

 Pleurotoma cerinum Stimpson, 1851, Shells of New England, p. 49, pi. ii, 



fig. 2. 

 Pleurotoma cerinum Holmes, 1859, Post-Pi. Fos. S. C, p. 77, pi. xii, figs. 9, 



9a. 

 Mangilia cerina Dall, 1889, Bull. U. S. Nat. Mus., No. 37, p. 102, pi. xliv, 



figs. 16, 16a. 

 Description. — " T. fusiformi-turrita cerea, vel cinerea, plicis longitudi- 

 nalibus, circa 10, elevatis, striis transversis numerosis; anfr. 7 planius- 

 culi; apertura oblonga, dimidiam spiram sub-asquante ; labro simplici; 

 cauda brevissima." Kurtz and Stimpson, 1851. 



This species is not common. It is a small form, rarely detected except 

 after a careful washing of the materials collected. 



The earliest occurrence of this species reported is by Dall from the 

 Pliocene of South Carolina (Waccamaw beds). Its range in the Pleisto- 



