GASTEEOPODA OP THE LOWER GEEEN MAELS. 69 



NOTES ON THE GENUS PIESTOCHILUS MEEK AND VOLUTOMORPHA GABB. 



In the report of the U. S. Geol. Surv. of the Terr., Vol. ix, Invert. Pal., 

 p. 356, Mr. Meek describes the genus Piestochilus as a division of the 

 FasciolariidiB. His description is as follows: 



Shells of small size, with spire and canal produced; volutions flattened or 

 moderately convex and finally spirally striated, sometimes with vertical folds; 

 plait or plaits of columella not exposed in a direct view into the aperture, very 

 oblique, and occupying a higher position than in either of the foregoing; [Fascio- 

 laria Lamarck and Terehrispira Conrad] outer lip smooth within. 



As the type he gives Fiisus Scarboroiighi M. & H. This shell is a 

 medium sized, rather slender, fusiform species, almost equally long above 

 and below the point of greatest diameter, which is at the swell of the body 

 volution ; the canal is rather short and straight, and the columella is provided 

 with two distinct, although small, very oblique folds. In examining the 

 shell few persons would fail to recognize at once its very close relations to 

 Fasciolaria Lamark, especially to such species as those forming the group 

 containing Lamark's type, F. tulipa; the principal differences being in the 

 more slender form and comparatively straight canal, which is not so abruptly 

 contracted at the base of the outer volution. They also somewhat resemble 

 a group of Mitras, such as M. scrohictilaria Broochi, and more distantly M. 

 granatina Lam., a living species, though differing in the form of the aper- 

 ture and in the character of the columellar folds. 



During the year in which the above-named work was published 

 (1867), Mr. W. M. Gabb described and published^ his genus Volutomorpha, 

 founding it upon Volutilithes Conradii Gabb, described and figvired in the 

 Jour. Acad. Nat. Sci., Phila., 2d ser., vol. 4, p. 300, PI. xlviii. Fig. 10. 

 This genus as typified by that species is quite distinct generically from 

 Piestochilus. The generic description originally given is: 



Shell elongate, fusiform ; whorls cancellated by longitudinal and revolving 

 ribs ; columella with one very oblique fold, and sometimes one or more smaller 

 secondary folds. In shape this genus is not unlike the two preceding genera [ Vol- 

 utoderma Gabb, and Fulgoraria Schum], but it differs from them all in having 

 essentially a single large oblique fold. When more than one occurs, the secondary 

 folds are smaller than the large primary. 



'Proc. Acad. Nat. Sci., Phila., 1876, p. 290. 



