NATICA (LUNATIA) HELICINA. 083 



Natica (Lunatia) helicina (Brocchi), Sacco. Plate LIV, figs. 4, 5. 



1814. Nerita helicina, Brocchi, Conch, foss. sub-ap., vol. ii, p. 297, pi. i, fig. 10. 



1856. Natica helicina (pt.), Homes, Foss. Moll. Tert. Wieu, vol. i, p. 525, pi. xlvii, fig. 7. 



1870. Natica helicina, A. Bell, Jouru. de Conch., vol. xviii, p. 349, no. 319. 



1874. Natica catena, Van den Broeck, Ann. Soc. malac. Belg., vol. ix, p. 120. 



1878. Natica helicina, de Stefani e Pantinelli, Bull. Soc. Malac. Ital., vol. iv, p. 140. 



1881. Natica helicina, Fontannes, Moll. Plioc. Vail, du Rhone, vol. i, p. 115, pi. vii, fig. 11. 



1882. Natica helicina, von Koenen, Norddeutsch. Miociin, vol. ii, p. 231. 



1886. Natica (Naticina) catena, Dollfus et Dautzenberg, Feuille de Jeunes Natur., vol. xvi, p. 141. 

 1889—91. Natica helicina and vars., Sacco, Boll. Soc. Ceol. Ital, vol. viii, p. 355, no. 1958, 1889 ; 

 N. Naticina (catena), var. helicina, Moll. Terr. Terz. Piem., pt. viii, p. 70, pi. ii, fig. 43, 1891. 



Specific Characters. — Shell solid, ovato-conical ; whorls 5 or 6, the last tumid, 

 much the largest, not so wide in proportion as in N. catena; ornamented indis- 

 tinctly by oblique, irregular and flexuous lines of growth ; spire short, small, 

 depressed ; suture slight ; mouth semilunar, angulate above, rounded below ; outer 

 lip not so much expanded as in the last species ; inner lip forming a rather thick 

 callus on the columella, which becomes narrow as it approaches the umbilicus, 

 and partly covers it, its margin being thickened near the base of the shell ; 

 umbilicus open, deep. 



Dimensions. — L. 22 mm. B. 18 mm. 



Distribution. — Not known living. 



Fossil: Coralline Crag: Sutton. Waltonian : Walton-on-Naze, 

 Little Oakley. 



Miocene : Touraine, North Germany, Belgium, Piedmont. 



Lower Pliocene : Rhone valley, Biot, Piedmont, Tuscany. 



Upper Pliocene : Astiano (rarissima, Sacco). 



Remarks. — The Crag fossils figured under this name, which are not very rare 

 at Oakley, agree with specimens I obtained some years ago from the Faluns of 

 Touraine, and equally with others from the Italian Pliocene which I have received 

 from my friend Prof. Issel, though not altogether with Brocchi's type figure which 

 resembles more nearly N. catena. Possibly the former is incorrectly drawn. My 

 Crag fossil of N. helicina (fig. 5) is very near to Prof. Issel's specimen (fig. 4), 

 as it is to that of Prof. Sacco. 



Wood's iV. helicina 1 (' Mon. Crag Moll.,' 1st Suppl., pi. iv, fig. 8) is, I think, 

 different, as are those given by Philippi (' Enum. Moll. Sic.,' vol. i, p. 163, pi. ix, 

 fig. 12), and by Lorie ('Arch. Mus. Teyl.' [2], vol. ii, p. 230, pi. v, fig. 11). 



For reasons given above I prefer to regard this species as specifically distinct 

 from N. catena. 



Homes figures two specimens as N. helicina, one of which {op. cit., fig. 7) is 



1 I have not been able to discover the specimen of the present species figured by Wood, which has 

 a very unusually formed spire. It might be called N. incerta. 



