342 PLIOCENE MOLLUSC A. 



Ocinebra tortuosa (J. Sowerby). Plate XXXV, figs. 7, 8. 



1825. Murex tortuosus, J. Sowerby, Min. Couch., vol. v, p. 48, pi. ccccxxxiv, fig. 2. 



1842-8. Murex tortuosus, S. V. Wood, Aim. Mag. Nat. Hist. [1], vol. ix, p. 540, 1842: Mon. Crag 



Moll., pt. i, p. 40, pi. iv, fig. 9, 1848. 

 1843-81. Murex tortuosus, Nyst, Coq. foss. Belg., p. 545, pi. xli, fig. 14, 1843; Couch. Terr. tert. 



Belg., p. 3, pi. i, fig. 1, 1881. 



1871. Murex erinaceus, var., Jeffreys in Presfwich, Quart. Jouru. G-eol. Soc, vol. xxvii, p. 489. 



1872. Murex tortuosus, A. aud E. Bell, Proc. Geol. Assoc, vol. ii, pp. 209, 213. 

 1890. Murex torhiosus, C. Eeid, Plioc. Dep. Brit., p. 247. 



1892. Murex tortuosus, Van den Broeck, Bull. Soc. Beige Grcol., vol. vi (Mcmoires), p. 131. 

 1914. Ocinebra tortuosa, F. YV. Harmer, Plioc. Moll. Gt. Brit,, pt, i, p. 125. 



Specific Characters'. — Shell fusiform, rugged and solid ; whorls 0, convex, 

 nngulated, with a sloping shelf below the suture, the last two-thirds the total 

 length ; ornamented by well-marked spiral ridges and on the upper whorls by 

 flattened and conspicuous longitudinal costae which are nodulous on the keel and 

 generally disappear towards the base of the shell, also by three strong and 

 prominent varices, oblique, tortuous or fimbriated, which cross both the shelf 

 -and the suture and are specially developed on the body-whorl ; spire rather short, 

 turreted, regularly diminishing in size towards a blunt apex; suture wide and 

 deep; mouth inequilateral; outer lip angulated by the keel, with a wide expanded 

 margin, thickened by the labial varix and strengthened outside by the spiral 

 ridges, denticulated within ; canal narrow, open, contracted, turning slightly to 

 the left. 



Dimensions. — L. 34 — 40 mm. B. 15 — 20 mm. 



Distribution. — Not known living. 



Fossil : Coralline Crag : Orford, Sutton, Ramsholt, Boyton. 

 Waltonian : Walton-on-Naze, Beaumont, Little Oakley. Newbournian : Waldring- 

 field, Newbourn, Sutton, Ramsholt, Shottisham, Felixstow. Butleyan : Butley. 

 Icenian: Bramerton. Scaldisien, Poederlien : Belgium. 



Remarks. — On p. 125, while calling attention to an imperfect specimen which 

 I then thought might be regarded as a variety of 0. tortuosa, I alluded incidentally 

 to that species, but a further study of the group to which it belongs suggests the 

 desirability of dealing more fully with this subject. 



In the non-photographic figures given by Wood in 1848 and by Nyst in 1881 

 (pp. cit.) the artists have not represented very accurately what seems to me its 

 typical forms as represented by specimens in my collection, either from the 

 Coralline Crag or from Oakley. In these the sculpture is mainly spiral on the 

 lower whorls, which are generally ornamented only by three prominent and oblique 

 varices, becoming spiny or nodulous on the keel. On the upper whorls there are 

 usually some small supplementary longitudinal costge which give that part of the 



