Maryland Geological Survey 477 



rather straight sides and quite abruptly constricted at the base into a 

 slender and probably rather produced anterior canal ; surface sculpture 

 known only from a fragment of the exterior retained at the base of the 

 body and from the axial ribbing upon the cast of the ultima; all trace of 

 costals lost upon the whorls of the spire, but four feeble and four rather 

 strong costae developed upon the body, the third from the aperture being 

 the strongest; fragment of outer surface very finely sculptured reticu- 

 lately, the spirals low, flattened fillets separated by channels of approxi- 

 mately the same width, overriding the very fine and feeble secondary 

 riblets ; sutures apparently deep, whorls quite widely separated in the cast ; 

 aperture elliptical ; outer lip arcuate, inner lip excavated, non-plicate. 



Dimensions (of imperfect specimen). — Altitude 46 mm., maximum 

 diameter 31 mm. 



The cast in question suggests Anchura compacta Whitfield, but differs 

 from it in the relatively higher body. 



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

 ant, Prince George's County. 



Collection. — Maryland Geological Survey. 



Suborder STREPTODONTA 



Superfamily PTENOGLOSSA 

 Family SCAL1DAE 



Genus FP1TONIUM Bolten 

 [Museum Boltenianum, 1798, p. 91] 

 Type. — Turbo scalaris Linne. 



Shell polished, turriculate, perforate or imperforate ; whorls numerous, 

 convex, often very loosely coiled ; sculpture dominantly axial, axial flanges 

 and varices often very prominent, usually continuous, and fused at the 

 suture, in many species forming the only points of contact between the 

 whorls; aperture subcircular or ellipsoidal; peristome entire, thickened, 

 reflected. 



Etymology: emroviov^ tuning wrench. 

 31 



