76 MOLLUSCA FROM THE CRAG. 



Shell turriculate, with flat volutions, subcarinate at the base ; finely striated trans- 

 versely, and banded at rather irregular distances, with two or three obtuse ridges, the 

 upper one nearly obsolete. 



Axis, 2% inches. 



Locality. Cor. Crag, Gedgrave and Ramsholt. 



Red Crag, passim. Recent, Mediterranean. 



This species is abundant, and very variable in regard to the number and arrange- 

 ment of its banded ridges. That which I considered as a distinct species, and named 

 bicinctus (Tab. ix, fig. 7 d] when my Catalogue was published, I have now reason to 

 believe is only a variety. The young or upper volutions of most specimens have the 

 banded ridges more prominent and distinct than upon the larger part of the shell. 

 Fig. 7 a appears to correspond with Brocchi's figures (Tab. vi, figs. 12 and 13), 

 which are, I imagine, only varieties with more elevated ridges. 



Figs. 7 a, d, are from the Coralline Crag. 



Figs. 7 6, c, are from the Red Crag. 



4. TURRITELLA PLANTSPIRA. S. Wood. Tab. IX, fig. 11. 



TURKITELLA PLANISPIRA. S. Wood. Catalogue 1842. 



Nyst. Coq. foss. de Belg. p. 401, pi. 38, fig. 9, 1844. 



T. Testa turritd, subulatd ; anfractibus planatis ; transversim striatis ; striis regu- 

 laribus sub-cequidistantibns. 



Shell turreted and tapering, with nearly flat volutions ; transversely striated ; striae 

 regular, nearly equidistant. 



Axis, 1J inch. 



Locality. Cor. Crag, Sutton. 



I have only been able to procure fragments of this species, and they appear to agree 

 with the shell figured by M. Nyst. The whorls are very flat, with scarcely a distinct 

 suture in some specimens. In the young state the middle ridge is always the most 

 prominent, taking off from the flatness of the volution, which distinguishes it when 

 further increased. The ridges or striae are generally regular, though sometimes alter- 

 nating, one large and one small. M. Nyst, as well as myself, have considered this 

 distinct, and it is rather singular that we should both have chosen the same name for 

 it. It is, however, possible this may be only a variety of T. communis, but I have never 

 seen that shell with such perfectly flat volutions, or so subulate in form. 



5. TURRITELLA CLATHRATULA. S. Wood, 1847. Tab. IX, fig. 6, 8 a. 



C. Testa turritd, subulatd, anfractibus novem convexiusculis ; lineis quinque elevatis 

 tranvsersis cinctis ; interstitiis striatis vel clathratis ; aperturd subquadratd. 



Shell turreted and tapering, with about nine slightly convex volutions, ornamented 

 with five transverse rather rounded ridges; the sulci between them longitudinally 

 striated or imbricated ; aperture subquadrate. 



