1916.] NATURAL SCIENCES OF PHILADELPHIA. 159 



Section A. New section. 



Type: Drilluta communis sp. nov. 



This section is characterized by shells of met limn size with well 

 rounded axials and a variable number of columella plaits which 

 terminate within the aperture. The spiral sculpture is very fine on 

 the spiral whorls and young individuals but well-defined on i 

 anterior part of the body of adult individuals, and lacking on the 

 posterior part of the older whorls of such individuals. This section 

 is proposed to include besides the Coon Creek species the form 

 "Drillia ? distans" Conrad 5 from Owl Creek, a closely related species 

 from Corsicana, Texas, and a poorly preserved specimen from Bright- 

 seat, Maryland. The descriptions and figures of Voluta lativittata 

 Griepenkerl 3 and Voluta canalifera (Favre) G. Muller 7 indicate 

 generic and sectional relations nearer to Section A of Drilluta than 

 to any other forms that have been found in the literature. 



Drilluta communis sp. nov. PI. XXIII, figs. .5 and 6. 



Description. — Shell of medium size and fusiform in outline: spire 

 elevated, its altitude approximately one-half the entire length of the 

 shell : apical angle higher on the posterior part of the spire, becoming 

 slightly lower on the younger whorls; protoconch very smooth and 

 trochoid, coiled about three times; whorls of conch closely appressed 

 and eight in number; both axial and spiral sculpture developed, the 

 former dominant, axial costse rounded and abruptly elevated, 11 to 

 17 in number to the whorl, 14 on the penultima of the type, costae 

 rlexuous, uniform in strength from the posterior fasciole to the 

 anterior suture and a little less than half way down to the base of 

 the body on the ultima; fasciole narrowed, indistinctly marked on 

 the early whorls, defined in the later whorls by the abrupt disappear- 

 ance of the axial costse; spiral sculpture of fine crowded impressed 

 lines on apical whorls, becoming faint and almost disappearing on 

 the medial part of older whorls, but reappearing as coarse, impressed 

 lines on slope of body whorl, becoming faint and disappearing on 

 anterior fasciole; suture impressed; body whorl sloping down smoothly 

 into a broad pillar; aperture lanceolate, produced anteriorly into a 

 very feebly recurved canal; inner lip callous; outer lip simple; colu- 

 mella marked by one well-defined fold and one or two weaker posterior 



5 Conrad, T. A., Jour. Acad. Nat. Sci., Philadelphia, 2d ser., vol. IV. p. 

 pi. 46, fig. 49, 1860. 



•Griepenkerl, O., 1889, Palaeonlologische Abhandl., Band IV. Befl ■">, p. 93 

 (395), Taf. viii, fig. 1, 1889. 



7 Muller, ('■., 1899, Abhandl. d. h'd-i. Preus.-geol. Landesanstalt, neue Folge, 

 Hefl 25, p. 124, Taf. xvi, figs. L3, I l. 

 31 



