HAEDROPLEURA SEPTANaULARIS. 251 



flexuous ribs which reach the suture aud uearly to the base, but not to the two 

 first whorls, which are smooth and polished ; also bj excessively fine spiral lines, 

 hardly visible without the aid of a lens ; suture well-marked ; mouth oval, narrow, 

 angulated above, continuous with a short and open canal ; labial notch distinct, 

 Init not so large as in some other of the allied species ; outer lip thickened by the 

 labial rib. 



Dimensions. — L. 10 — 12 mm, B. 8 mm. 



Distribution. — Not recorded livinsf. 



Fossil : "Waltonian Crag : Little Oakley. 



Upper Pliocene : Sicily — Altavilla ; Northern Italy — Astiano. 



Remarks. — I have obtained half a dozen examples of a charming little shell at 

 Oakley, v/hich, among the many hundred Pleurotomidia3 I have collected at that 

 place, seem to separate themselves clearly from the rest. 



The only thing I can find to which they may be referred is a species described 

 by the Abbe Brugnone in 1862 from the Upper Pliocene deposits of Altavilla near 

 Palermo; of this the Marchese di Monterosato has been kind enough to send me some 

 specimens, one of which I have figured for comparison with a fossil from the Crag. 



In its general appearance M. ambigua is not unlike some other of Mangilia 

 here described, but it is regarded by Italian conchologists as distinct ; indeed, it 

 was formerly grouped with Rapliitoma, Sign. Cipolla remarking that it appears to 

 be an intermediate form, uniting these two genera. 



Genus HAEDROPLEURA, Monterosato, 1S82. 



Haedropleura septangularis (Montagu). Plate XXVII, fig. 27; Plate XXIX, 



figs. 3, 4. 



1803. Miirex septangularis, Montagu, Test. Brit., pt. i, p. 268, pi. ix, fig. 5. 



1844. Pleurotoma septangular e, Philippi, Enum. Moll. Sicilise, vol. ii, p. 169. 



L853. Mangelia (Bela) septangularis, Forbes and Hanley, Brit. Moll., vol. iii, p. 458, pi. cxii, 



figs. 6, 7. 

 1865. Pleurotoma septangularis, C. B. Rose, Geol. Mag., vol. ii, p. 11. 

 1867. Pleurotoma septangularis, Jeffreys, Bi"it. Conch., vol. iv, p. 390, pi. xci, fig. 5. 

 1872. Pleurotoma septangularis, S. V. Wood, Mon. Crag Moll., 1st SuppL, pt. i, p. 38, pi. vi, fig. 16. 

 1873-5. Bela septangularis, Seguenza, Boll. R. Com. Geol. Italia, vol. iv, p. 298, no. 109, 1873 ; vol. vi, 



p. 206, no. 173, 1875. 

 1877. Bela septangularis, Bellardi, Moll. Terr. Terz. Piem., pt. ii, p. 147. 

 1883. Haedropleura septangularis, Bucqnoy, Dautzenlierg et Dollfus, Moll. mar. Eonss., vol. i, p. 110, 



pi. xiv, figs. 26, 27. 

 1890. Haedropleura septangularis, Carus, Prod. Faun. Medit., vol. ii, p. 414. 

 1893. Pleurotoma septangularis, A. Bell, Ann. Rep. Yorks. Phil. Soc, p. 64. 



