330 PLIOCENE MOLLUSCA. 



this group that may be found hereafter in our British deposits ; an imperfect 

 specimen of N. semistriata, now in the British Museum, has been obtained at St. 

 Erth by Mr. Bell. 



By H. and A. Adams Amycla was used for a separate genus allied to Colnmbella. 

 By some authorities, including P. Fischer, it has been regarded as a sub-genus of 

 Nassa. M. Cossmaun, however, figures the present species as Zeuxis [Amycla) 

 semistriata and as the typical form of this group of the mollusca. 



Nassa (Amycla) labiosa (J. Sowerby). Plate XXXIV, figs. 20, 21. 



1825. Buccinum labiosum, J. Sowerby, Min. Conch., vol. v, p. 122, pi. cecclxxvii, fig. 3. 



1842-74. Nassa labiosa, S. V. Wood. Aim. Mag. Nat. Hist. [1], vol. ix, p. 540, 1842 ; Mon. Crag 



Moll., pt. i, p. 28, pi. iii, fig. 8 ; pi. vii, fig. 22, 1848; 1st Suppl., pt. i, p. 15, 1872 ; pt, ii, p. 176, 



1874. 

 1843-81. Buccinum labiosum, Nyst, Coq. foss. Terr. Tert Belg., p. 577, no. 495, pi. xliii, fig. 14, 1843 ; 



Nassa labiosa, Conch. Terr. tert. Belg., p. 31, pi. ii, fig. 13, 1881. 

 1854. Buccinum labiosum, Beyrich, Zeitschr. Deutsch. G-eol. Gesell., vol. vi, p. 462, pi. viii, fig. 5. 



1871. Nassa semistriata, Jeffreys in Prestwich, Quart. Journ. G-eol. Soc, vol. xxvii, pp. 144, 489. 



1872. Nassa labiosa, A. and R. Bell, Proc. Geol. Assoc, vol. ii, pp. 203, 208, 213. 



1874-92. Nassa semistriata, var. labiosa. Van den Broeck, Ann. Soc. Malac. Belg. (Memoires), vol. ix, 

 pp. 120, 135; N. labiosa, vol. ix, pp. 260, 266, 272, 280, 285, 1874; vol. xiv, p. 74, 1879; vol. xvii, 

 pp. 202, 204, 1832 ; vol. xix, pp. 9, 18, 1884; Bull. Soc. Belg. Geol. (Memoires), vol. vi, pp. 121, 

 132, 147, 1892. 



1890. Nassa labiosa, C. Reid, Plioc. Dep. Brit., p. 248. 



1912. Nassa labiosa, Tesch, Med. v. d. Rijks. v. Delfstoffen, no. iv, p. 80, no. 198. 



1914. Nassa labiosa, F. W. Harmer, Plioc. Moll. Gt. Brit., pt. i, p. 72. 



Specific Characters. — Shell small, ovate ; spire elongato-conical ; whorls 6 — 7 ; 

 but little convex, rounded and slightly excavated at the base ; ornamented by fine, 

 regularly-spaced, rather deeply-cut sulci, about 16 to 18 on the last whorl ; suture 

 slight, canaliculated ; mouth ovate, angulate above, rounded below; outer lip thin, 

 denticulate ; inner lip forming a wide glaze on the pillar; canal very short. 



Dimensions. — L. 16 mm. B. 8 mm. 



Distribution. — Not known living. 



Fossil : Coralline Crag : (ledgrave, Sutton, Boyton. Waltonian : 

 Walton-on-Naze, Beaumont, Little Oakley. Newbournian and Butleyan : passim. 

 Wexford gravels. Bolderien, Diestien,Scaldisien,Poederlien : Belgium. Scaldisien, 

 Poederlien : Holland. 



Pleistocene of Sicily : Ficarazzi. 



Remarks. — Nassa labiosa was known to Wood from the Coralline and New- 

 bournian horizons, though not as an abundant shell; indeed in 1874 (pp. c/7.,p. 176) 

 he seemed inclined to think it might be derivative at the latter ; more recent work, 

 however, has shown it to be one of the most characteristic fossils of the Waltonian 

 Crag. I have collected some hundreds of specimens of it at Oakley. 



