2o R. BULLEN NEWTON on 



Family TURRID^ (= Pleurotomida.) 

 Surcula ingens (Mayer-Eymar). 



PLATE 2, figs. 3-5. 

 Pleurotoma ingens. 



Mayer-Eymar : Journ. Conchyl. 1895, Vol. 43, pp. 50, 51, pi. 4, fig. i. 



Pleurotoma {Surcula) ingens. 



Oppenheim : PaJaeontographica 1906, Vol. 30, part 3, pp. 332-333, pi. 24, figs. 26. 



REMARKS. This determination applies to a remarkably fine example of this 

 species measuring 92 by 50 millimetres, equalling in dimensions as well as 

 excelling in structural details that figured by Oppenheim from the Upper 

 Mokattam (= Bartonian) beds of the Fayoum of Egypt, which however, is only 

 about half the size of Mayer-Eymar's giant type from the same locality 

 possessing a length and width respectively of 170 by 65 millimetres. In 

 general form the present example is more or less biconical and turreted, while 

 the spire is much shorter than the body whorl. The posterior floor of the 

 whorls is wide, slightly concave, and separated above by a deep linear and 

 rather irregular suture, while below is a conspicuous periphery composed of 

 wedge-shaped, equi-distant tubercles flattened at the top and forming short, 

 oblique, rod-like swellings on the anterior face of the whorl, which is vertical 

 and narrow compared to the broadened surface above, besides being furnished 

 with a few strong, irregular, spiral costae which are continued as fine striations 

 over the tubercles. The wide posterior surface of the whorls is covered with 

 extremely fine, close, and deeply oval sinuated lines, which are well within 

 the tubercled or peripheral margin and the suture, these lines being crossed 

 by a series of equi-distant and delicate spiral striations. The spire consisting 

 of 9 whorls is complete with the exception of the protoconch, while the body 

 whorl, occupying about three-fifths of the longitudinal axis of the shell, has a 

 piriform mouth which is prolonged into a slightly twisted canal ; there is 

 besides, a smooth internal surface to the labrum, and a prominent smooth 

 callosity covering the columella region from the posterior angle to the termi- 

 nation of the canal. The deeply sinuous lines on the posterior surface of the 

 body-whorl are continued over the periphery and inflated region below, as 

 graceful outward curvatures which on the canal surface become nearly perpen- 

 dicular to the end of the canal, where they merge into a twisted condition. 

 Crossing the lines of curvature and slightly below the periphery occur three 



