PLEUROTOMA TURRICULA. 203 



those which can now be produced by photography. For such reasons it seems 

 desirable to deal rather fully with the present family, bringing together, side by 

 side on the same plate, the various forms, often closely allied, of the different 

 genera into which it has been divided which are represented in our Crag deposits. 



These are mainly of a more recent type than the large species characteristic of the 

 Miocene and the Lower Pliocene of Italy (Piacenziano), as, for example, those now 

 grouped under the generic names Clavatida, Surcnla, and in part of Pleurotoma. 

 Such forms are better represented in the Miocene of the North Sea basin, and, 

 as far as the evidence goes, in the Lenham beds, where we find Clavatula 

 Joiianneti and Surcnla consohriua. The more representative Pleurotomidffi of the 

 East Anglian Crag are smaller shells, like BeJa, Bayhitoma , MangUla, Clafliurella^ 

 and Brillia, pointiug to a closer relation of our deposits, from the Coralline 

 horizon upwards, with the Upper Pliocene of Italy and Sicily (Astiano), and with 

 the Pleistocene deposits of Sicily, Calabria, and Tuscany.^ The large number of 

 such forms reported here for the first time from the Crag and mostly from one 

 section, leads me to the belief that our lists of fossils may l)e largely extended by 

 continued and careful investigation in other localities, but few of which have been 

 thoroughly explored. 



I fear, however, that, so far as the present group of Mollusca is concerned, few 

 of the earlier lists can be wholly relied on. 



Genus PLEUROTOMA, Lamarck, 1799. 

 Pleurotoma turricula (Brocchi). Plate XXVI, figs. 1, 2. 



1814. Murex turricula, Brocchi, Conch, foss. Subap., vol. ii, p. 435, pi. ix, fig. 20. 



1843. Pleurotoma turricula, Nyst, Coq. foss. Terr. Tert. Belg., p. 520, pi. xli, fig. 5. 



1848. Pleurotoma turricula, S. V. Wood, Mon. Crag Moll., pt. i, p. 53, pi. vi, fig. 1 h. 



1853. Pleurotoma ttirricula, Homes, Foss. Moll. Tert. Wien, vol. i, p. 350, pi. xxxviii, fig. 1. 



1853. Pleurotoma turrifera, Nyst, in O. d'Halloy, Abrege de GeoL, p. 588. 



1872. Pleurotoma turrifera, S. V. Wood, Mon. Crag Moll., 1st Suppl., pt. i, p. 33. 



1875. Pleurotoma turricula, Seguenza, Boll. R. Com. Geol. Ital., vol. vi, p. 204, no. 137. 



1877. Pleurotoma turricula, Bellardi, Moll. Terr. Terz. Piem., pt. ii, p. 39, pi. i, fig. 25. 



1879. Pleurotoma turricula, Fontannes, Moll. Plioc. Vail, du Rhone, vol. i, p. 41, pi. iv, fig. 6. 



1881. Pleurotoma turricula, Nyst, Conch. Terr. Tert. Belg., p. 42. 



1890. Pleurotoma turricula, E. Vincent, Bull. Soc. Malac. Belg., vol. xxv, p. 97 (fig-). 



1896. Pleurotoma turricula, Bernays, Bull. Soc. Beige Geo!., vol. x (Memoires), p. 128. 



1907. Pleurotoma turricula, Eavn, Kgl. Danske Vid. Selsk. Skrift. [7], vol. iii, p. 248. 



8'pecijic Characters. —^heW slender, elongato-fusiform ; whorls nearly flat, 

 ornamented by three strong and rather distant spiral ridges, sometimes granulate, 



^ With the Sicilian deposits which I regard as Pleistocene, Seguenza grouped others at Livorno, 

 Reggie, and elsewhere. 



