NATIOA (LUNATIA) EXVARIANS. 689 



has included it in his list of Lusitanian species in the post-glacial (Tapes-banks) 

 of the Christiania region. 



The specimens of N. Alderi in my collection, both from the Coralline and 

 Icenian Crags, are smaller than that figured by Wood from the Nar valley, which 

 corresponds with the size of the typical British form. 



It is the N. intermedia of Philippi, but has been more usually known under 

 Forbes' specific name of Alderi. MM. Dautzenberg and Fischer, however, have 

 recently revived Donovan's earlier name of nitida, identifying the latter with our 

 shell. They consider, moreover, the one figured by Forbes and Hanley as 

 N. pusilla (op. cit., pi. c, fig. 7) to be the same. 



Mr. R. B. Newton reports N. Alderi (nitida) from a Miocene block of f ossiferous 

 limestone dredged in the North Sea (' Quart. Journ. Geol. Soc.,' vol. lxxii, pi. ii, 

 fig. 7, 1917), but the specimen he figures does not appear to me a typical example 

 of our British shell. 



Natica (Lunatia) exvarians (Sacco). Plate LIV, figs. 15, 1G. 



1842—8. Natica elevata, S. V. Wood, Ann. Mag. Nat, Hist. [1], vol. ix, p. 529, 1842 ; N. variant, 



Mon. Crag Moll., pt, i, p. 143, pi. xvi, fig. 6, 1848. 

 1843—81. Natica hemiclausa, Nyst, Coq. foss. Belg., p. 446, pi. xxxviii, fig. 15. 

 1856. Natica helicina, Homes, Foss. Moll. Tert. Wien, vol. i, p. 525, pi. xlvii, fig. 6. 

 1871. Natica cirriformis, var., Jeffreys in Prestwich, Quart, Journ. G-eol. Soe., vol. xxvii, pp. 144, 



489. 

 1881. Natica various, Nyst, Conch. Terr, tert, Belg., p. 70, pi. v, fig. 10. 



1890. Natica varians, C. Reid, Plioc. Dep. Brit., p. 249. 



1891. Natica (Naticina) catena, var. exvarians, Sacco, Moll. Terr. Terz. Piem., pt, viii, p. 70. 



1892. Natica varians, Van den Broeck, Bull. Soc. Belg. G-eol., vol. vi (Mcmoires), pp. 122, 133. 



1896. Natica varians, Bernays, Bull. Soc. Belg. Gc'ol., vol. x (Me'moires), p. 128. 



1897. Natica (Neverita) varians, A. Bell, Trans. Roy. Geol. Soc. Cornwall, vol. xii, p. 145, pi. ii, 

 fig. 5. 



1898. Natica varians, F. W. Harmer, Quart. Journ. Geol. Soc, vol. liv, p. 317. 



Specific Characters. — Shell strong and solid, smooth, polished, ovato-conical, 

 much larger than the typical Miocene N. varians; spire elevated, fairly long ; whorls 

 5 or 6, convex, overlapping, the last much the largest, four-fifths the total length ; 

 wrinkled near the mouth by the lines of growth ; suture well-marked but not deep ; 

 mouth large, semilunar, outer lip gently rounded, sharply incurved upon the body- 

 whorl, one-third of which it leaves uncovered, obtusely rounded below ; inner lip 

 straight, forming a thick and rather wide callus on the columella ; umbilicus large, 

 open, deep. 



Dimensions. — L. 25 — 28 mm. B. 20 — 24 mm. 



Distribution. — Not known living. 



Fossil : Lenham. Coralline Crag : Gedgrave, Sutton, Ramsholt. 



