762 CRETACEOUS PALEONTOLOGY. 



1905. Pyrifusus turritus Johns., Proc. Acad. Nat. Sci. Phil. 

 (1905), p. 24 (in part). 



Description. — Shell fusiform with seven or eight volutions, 

 produced below into a rather slender, straight, anterior canal, 

 spire slender, about four-fifths as high as the aperture; the 

 dimensions of a nearly complete shell from the Ripley forma- 

 tion of Mississippi are : total height, 36.5 mm. ; height of spire, 

 17 mm.; maximum diameter of shell, 15 mm.; apical angle, 48° 

 to 50°. Outer volution somewhat ventricose above and con- 

 tracted below intO' the anterior canal. Just below the suture 

 the shell is marked by a rather narrow, crenulated, revolving 

 band, below which the volutions expand somewhat abruptly; 

 shell marked by strong vertical folds, about 12 of which occupy 

 the outer volution. These folds are slightly oblique and are 

 somewhat curved, the concave side being directed towards the 

 aperture, they become obsolete below the middle of the outer 

 volution, the lower canaliculate portion of the shell being marked 

 by rather fine revolving ribs. Aperture elongate, rounded above, 

 pointed below; outer lip thin, columella marked by a single re- 

 volving fold, which is situated high up, and so far back that it can 

 scarcely be seen from the aperture in complete examples of the 

 shell. 



Remarks. — The above description of the shell of this species 

 has been made from a nearly complete example from the Ripley 

 formation of 'Mississippi, No. 20490, of the invertebrate pale- 

 ontological collection of the National Museum at Washington. 

 The New Jersey examples, including the type of the species, are 

 all internal casts. They have the same general form as the 

 shell described, but the volutions are not preserved to the apex 

 of the spire, the vertical folds are not so strong, the revolving 

 ribs of the lower portion of the outer volution are absent, or 

 very faintly marked, and the columellar fold shows as a groove. 

 The species is intermediate in its characters between O. typicus 

 and 0. mticronatai. It differs from the former in being less 

 abruptly contracted below to the anterior canal, and from the 

 latter in being more robust and less slender. The columellar 



