MARYLAND GEOLOGICAL SURVEY 155 



obsolete between the ribs ; ribs terminated below the suture by a narrow 

 smooth band, above which is a strong revolving line which margins the 

 suture; mouth f the length of the shell, nearly uniform in width for 

 the greater part of its length, but widening slightly near the upper end ; 

 beak slightly curved; nucleus two-whorled, globose, smooth for a whorl 

 and a half, then with faint reticulate markings. 



Length, 8 mm,; diameter, 2 mm. 



Occurrence. — Choptank Formation. Jones Wharf. 



Collection. — Maryland Geological Survey. 



Subgenus GLYPHOSTOMA Gabb. 



Mangilia (Glyphostoma) obtusa n. sp. 

 Plate XLII, Fig. 6. 



Description. — Shell short, six-whorled, spire -J the length of the shell; 

 later whorls with about eight obtuse nodes; entire shell covered with 

 faint raised revolving striae of which there are two very distinct ones on 

 the line of nodes; lines of growth faint; mouth narrow; labiimi with a 

 large serrated callosity at the posterior end and about nine small denticles 

 along the columella; labrimn thickened, and with about eight denticles 

 along its inner face. 



Length, 10 mm.; widtli, 4 nmi. 



Occurrence. — Calvert Formation. Plum Point. 



Collections. — Maryland Geological Survey, U. S. National Museum. 



Genus DRILLIA Gray. 



Drcllia incilifera (Conrad). 



Plate XLII, Fig. 7. 



Fleurotoma gracilis GoQT&d, 1830, Jour. Acad. Nat. Sci. Phila., vol. vi, 1st ser., p. 



235, pi. ix, flg. 10. 

 Pleurotoma incilifera Courad, 1834, Jour. Acad. Nat. Sci. Pliila., vol. vii, 1st ser., 



p. 140. 

 Pleurotoma gracilis Conrad, 1842, Proc. Nat. Inst., Bull, ii, p. 187. 

 Surcula gracilis Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 561. 

 Sxrcula gracilis Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 21. 

 Not Pleurotoma gracilis Brander. 



Description. — "Shell subfusiform; spire and beak attenuated; whorls 

 with two revolving rows of tubercle? on each, divided by a striated 



