534 PLIOCENE MOLLUSCA. 



references can liardly be relied on. The specimen from the Upper Pliocene of 

 Monte Mario, however, figured by Sign. Cerulli-Irelli as S. frond osa, seems to be 

 the true Crag shell. 



8tih-genus CLATHRUS, Oken, 1815. 

 Scala (Clathrus) communis (Lamarck). Plate XLVII, figs. 28, 29. 



1819. Scahria communis, Lamarclc, Auim. sans Vert., vol. vi, p. 228, no. 5. 



1836 — 43. Scalaria comm.unis, Pliilippi, Enum. Moll. Sic, vol. i, p. 167, pi. x, fig. 3, 1836 ; vol. ii, 



p. 144, 1843. 

 1846. Scalaria clathrus, Loven, K. Svensk. Vet.-Alcacl. Forli., vol. iii, p. 88. 

 1853. Scalaria communis, Forbes and Hauley, Brit. Moll., vol. iii, p. 206, pi. Ixx, figs. 9, 10. 

 1859. Scalaria communis, G. B. Sowerby, 111. Ind. Brit. Shells, pi. xv, fig. 16. 

 1867 — 71. Scalaria cormnunis, Jeffreys, Brit. Conch., vol. iv, p. 91, 1867 ; vol. v, pi. Ixxi, fig. 3, 1869 ; 



Quart. Journ. Greol. Soc, vol. xxvii, p. 491, 1871. 



1871. Scalaria communis, Nyst, Ann. Soc. malac. Belg., vol. vi, p. 98, no. 59. 



1872. Scalaria communis, A. and K. Bell, Proc. Greol. Assoc, vol. ii, p. 210. 



1873 — ^Q. Scalaria communis, Segnenza, Boll. E. Com. Geol. Ital., vol. iv, p. 354, no. 320, 1873 ; 



vol. V, p. 282, no. 115, 1874; vol. vii, p. 98, no. 618, 1876. 

 1874. Scalaria communis, S. V. Wood, Mon. Crag Moll., 1st Suppl., pt. ii, p. 183, add. pi., fig. 5. 

 1884. Scalaria (Clathrus) communis, Bucquoy, Dautzeuberg et Dollfus, Moll. mar. Rouss., vol. i, 



p. 240, pi xxiii, figs. 14—17. 

 1890. Scalaria (Clathrus) communis, Carus, Prod. Faun. Medit., vol. ii, p. 291. 

 1892. Scalaria communis, Locard, Coq. mar. Cotes de France, p. 126, fig. 111. 

 1892. Scalaria communis, A. Bell, Rep. Yorks. Phil. Soc, p. 63. 



1901. Scalaria communis, Br0gger, Norges geol. Unders^gelse, no. 31, p. 661, pi. xvii, fig. 18. 

 1905. Scala {Clathrus) communis, Kobelt, Icon, schalentrag. europ. Meeresconch., vol. iii, p. 4, pi. lix, 



figs. 1—11, 14—19. 

 1907. Scalaria (Clathrus) commmiis, Scalia, Att. Accad. Gioen. Sci. Nat. Catania [4], vol. xx, p. 33, 



no. 251. 

 1912. Scala (Clathrus) communis, Cossmann, Ess. Pak'oconch. compar., vol. ix, p. 36, pi. i, fig. 40. 



Specific Characters. — Shell solid, imperforate, conical, turriculate ; whorls 

 convex, disjoined, with a smooth surface ; ornamented by longitudinal costpe, 

 about 9 on the body-whorl, distant, slightly curved and reflected, not flattened, 

 rarely varicose, rather broader above, each cemented to that on the succeeding 

 whorl so as to form a continuous and oblique series ; spire tapering regularly to 

 a blunt and slightly inflected apex ; sutures fairly deep ; mouth subelliptical, 

 angulated above and below ; peristome continuous, thickened by the labial ril) and 

 by the inner lip, which is broad at the base. 



Dhne7islo7is. — L, 30 — 40 mm. B. 10 — -15 mm. 



Distribution. — Recent : British coasts, Finmark to the Canary" Islands, Mediter- 

 ranean, Adriatic, ^gean. 



Fossil : Waltonian Crag : Little Oakley. Newbournian : Wald- 



rmg 



field. 



