Maryland Geological Survey 411 



acteristie, and shows a somewhat larger individual than any which 1 have 

 seen."— Whitfield, 1892. 



Type Locality. — New Jersey. 



Weller included this species together with Actcon ovoidea Gabb under 

 the name of Acteon cretacea Gabb. The type of A. cretacea is much 

 crushed and shows no trace of spiral sculpture, although it quite possibly 

 may have been present originally. It differs further, however, in the 

 development of two strong columellar plications. Acteon ovoidea Gabb is 

 less cylindrical and more ovoidal in outline with a much more rounded 

 body whorl, more sharply constricted at the base. 



Acteocina forbesiana (Whitfield) has a very meager representation in 

 Maryland. 



Occurrence. — Monmouth Formation. Brooks estate near Seat Pleas- 

 ant, Prince George's County. 



Collections. — Maryland Geological Survey, Columbia University, New 

 Jersey Geological Survey. 



Family SCAPHANDRIDAE 



Genus CYLICHNA Loven 

 [Ind. Moll, of Scandinavia, 1846, p. 10] 



Type. — Bulla cylindracea Pennant. 



Shell small, subcylindrical, involute ; frequently umbilicated ; spire 

 deeply perforated at the summit ; aperture narrow, the outer margin 

 longer than the axis of the shell ; labrum sharp ; labium thickened ante- 

 riorly and bearing a more or less conspicuous plication. 



A genus that has been in existence since the Mesozoic and is repre- 

 sented in nearly all of the recent seas. 



Cylichna recta Gabb 



Plate XVIII, Pigs. 10, 11 

 Bulla recta Gabb, I860, Jour. Acad. Nat. Sci., Phila., 2d ser., vol. iv, p. 302, 



pi. xlviii, fig. 16. 

 Cylichna recta Meek, 1864, Check List Inv. Fossils, N. A., Cret. and Jur., 



p. 16. 



Etymology: Kv\ix»v, a small cup. 



