1917.] NATURAL SCIENCES OF PHILADELPHIA. 287 



narrow peripheral region, abruptly constricted in front of the periph- 

 ery; sculpture spiral, spinose and laminated in the type species; 

 incrementals sinuous in character, forming a reentrant angle along 

 the posterior keel ; aperture subovate, produced in front into a narrow 

 canal; outer lip sinuous at the shoulder angle; inner lip reflected, 

 not always adnate to the body and pillar, a chink occasionally present 

 between the inner lip and pillar; pillar slender and elongate often 

 curved or bent near the anterior extremity. 



This genus has an acute spire and is characterized by a highly 

 inflated body with a narrow peripheral region abruptly constricted 

 in front of this periphery. The pillar is long and variable. The 

 sculpture is dominantly spiral with laminar, somewhat zig-zag 

 incremental lines. This genus is proposed to include two known 

 species, one from Coon Creek and another from both Ripley and 

 Dumas, Mississippi, both of which are represented by several well 

 preserved specimens that present generic features that cannot be 

 included within the limits of any* of the described groups. The 

 general form of the genus suggests Hercorhijnchus^^ or possibly 

 Pyrifusus. However, the strong sinuations of the axials along the 

 shoulder is a character by which it may be readily separated from 

 any of the previously known Busyconidse. There is a tendency 

 toward low, obtuse spires in most of the genera of this family, yet 

 some forms, such as Pyrifusus, are acute at the apex. With age, 

 however, this low angle of the spire greatly increases, a feature very 

 characteristic of Scobina. The strongly inflated, bicarinate body of 

 the South Indian Upper Cretaceous form Rapa cancellata (ex parte) 

 Stoliczka^^ resembles Scobina somewhat but the South Indian form 

 is umbilicate, and not acute spirally. Ra2)a has a well defined um- 

 bilicus. Pyropsis differs from Scobina in having a low spire and no 

 laminar incremental ornamentation. These characters will also 

 serve to separate Scobina from Trochifusus}^ 



Scobina bicarinata n. sp. PI. XVIII, figs, l, 2. 



Description. — Shell of medium size and top-shaped; spire acute 

 at the apex, its elevation less than half the total altitude of the shell; 

 angle of spire increasing with age; whorls six in number, closely 

 appressed, increasing in size to an inflated body, whorls of spire 



16 Conrad, T. A., 1860, Jour. Acad. Nat. Sci. Phila., 2d ser., Vol. IV, p. 286, 

 Pi. XLVI, fig. 4; 1868, Amer. Jour. Conch., Vol. IV, p. 247. 



" Stoliczka, F., 1868, Geol. Survey India, Pal. Indica, Cret. Faunas South 

 India, Vol. II, p. 154, PI. XII, figs. 12-16. 



18 Gabb, W. M., 1876, Pkuc. Acad. Nat. Sci., Phh.a., p. 285. 



