OCINEBRA PSEUDO-NYSTII. 343 



shell a clathrated appearance. In the variety for winch T propose the name 

 clathrata (figs. 10 and 1 I)- these costae are strengthened and extend to the 

 body-whorl, giving' the whole shell a reticulate sculpture. 



This variety (clathrata), however, is less common that that shown in figs. 7, 8, 

 which I consider more typical. 



0. tortuosa is fairly abundant at Oakley, where I have obtained a considerable 

 number of specimens, but it seems to be less so in the Coralline or in the later 

 zones of the Red Crag, though generally present there. 



According to Nyst and Van den Broeck it is rare in the Belgian Pliocene. 



Jeffreys regarded 0. tortuosa as a variety of 0. erinacea, a view which Nyst 

 appeared inclined to support. I follow Wood, however, in considering them 

 specifically distinct, the former being an extinct and characteristic Waltonian 

 fossil, the latter a recent and a pre-eminently Pleistocene shell. 



The various forms of Ocinebra described in the following paragraphs have, more 

 or less, a family likeness to 0. tortuosa. They are each distinguished, however, 

 by certain features by which they may be identified without much difficulty. I 

 think it desirable, therefore, to retain the names by which they have been hitherto 

 known, figuring specimens of them together on the same plate, that students may 

 the more easily appreciate the grounds on which Wood regarded them as 

 specifically distinct. 



Var. minor, F. W. Harmer. Plate XII, figs. 9—11 ; Plate XXXV, fig. 9. 



1914. Ocinebra tortuosa, var. minor, F. W. Harmer, Plioc. Moll. Gt. Brit., pt. i, p. 125, pi. xii, 

 figs. 9—11. 



Remarks. — This specimen is from Oakley ; it is a somewhat more delicate shell 

 than any of the varieties of 0. tortuosa already figured. 



Ocinebra pseudo-Nystii (S. V. Wood). Plate XXXV, fig. 12. 



1879. Murex pseudo-Nystii, S. V. Wood, Mou. Crag Moll., 2nd Suppl., p. 14, pi. i, fig. 8. 

 1890. Murex pseudo-Nystii, C. Eeid, Plioo. Dep. Brit., p. 247. 



Specific Characters. — Shell of moderate size, strong, sub-fusiform ; whorls 7, 

 convex, not strongly angulate above, the last about two-thirds the total length ; 

 ornamented by 8 — 9 varices, thin, lamellate and compressed, more or less equal in 

 size, not spinous, and by well-marked and flexuous spiral ridges ; spire elevated, 

 gradually diminishing upwards to a blunt point ; suture fairly deep ; mouth ovate 

 with a distinct and narrow canal ; outer lip indistinctly denticulate within. 



Dimensions. — L. 24mm. B. 12 mm. 



45 



