674 PLIOCENE MOLLUSCA. 



southwards from Norway to the Hebrides and thence, according to some autho- 

 rities, to the Atlantic coast and to the Mediterranean. 



Their fossil distribution seems to have been similar. The larger form, 

 .V. clausa, has been reported from the Pleistocene beds of Christiania under the 

 name of N. qffinis, one of the specimens figured by Prof. Br0gger measuring 

 32 mm. in height, as well as from the Post-Pliocene of Montreal and of Japan. 



The specimens here figured from the last-named districts I received, one from 

 my old friend the late Dr. G. J. Hinde, and the other from Prof. Yabe, who 

 informed me it came from some shelly sands at Tokio which he regarded as of 

 Pleistocene a°/e. 



The shell figured by Gould as N. clausa was only about 15 mm. high, but he 

 stated he had seen a specimen from the banks of Newfoundland as large as that of 

 Sowerby's type. Prof. Posselt mentions a Natica from Greenland under the name 

 of N. affinis, but without figure or general description, which he says measured 

 30 mm. in height, and may probably have belonged to the present species. 

 Neither the typical northern form to which I confine the name .V. clausa, nor its 

 closely allied X. occlusa, are common in the earlier horizons of the Crag, but there 

 is a small Natica, described in the next paragraph as .V. affinis, differing from 

 it not only in size, but in form, of which I have obtained a hundred specimens 

 from the early Red Crag of Oakley, and it is fairly abundant at many other Crag- 

 localities. There is a striking similarity in the specimens here figured from 

 different localities as JV. clausa, and, I think, an equally striking difference 

 between them and the Oakley shells; the latter correspond with some I obtained 

 some years ago from the Pleistocene deposits of Reggio in Calabria which seem 

 identical. The one form is distinctly northern and arctic, the other boreal with 

 a southern range. 



Natica affinis (Gmelin). Plate LVI, figs. 6, 7. 



1790. Nerita affinis, Gmelin, Syst. Nat,, ed. xiii, p. 3675. 



1841 - 70. Natica clausa, Gould, Rep. Inv. Mass., ed. 1, p. 238, fig. 167, 1841 ; ed. 2, p. 312, fig. 612, 1*70. 



1869—71. Natica affinis, Jeffreys, 1 Brit. Conch., vol. v, p. 215, pi. cii, fig. 3, 1869 ; in Prestwirh, 



Quart. Journ. Geol. Soc, vol. xxvii, p. 489 (pt.), 1871. 

 1871—1915. Natica affinis, A. Bell, Geol. Mag. [1], vol. viii, p. 454, 1871 ; Rep. Brit. Assoc. (Leeds), 



pp. 410, 414, 415, 1890 ; Proc. Roy. Phys. Soc. Edin., vol. xii, p. 22, 1892 ; Geol. Mag. [6], vol. d, 



p. 168, 1915. 

 1872. Natica affinis, A. and R. Bell, Proc. Geol. Assoc, vol. ii, pp. 209, 213, 216. 

 1878. Natica affinis, G. O. Sars, Moll. Reg. arct. Norv., pp. 160, 358, pi. xxi, fig. 14. 

 1878. Natica, affinis, Monterosato, Enum. e Sinon. Conch. Medit. (Giorn. Sci. Nat. ed Econ. Palermo, 



vol. xiii), p. 36. 

 1890. Nnti,-,, affinis, Carus, Prod. Faun. Medit., vol. ii, p. 302. 



1 The references by Jeffreys and some other writers to N. affinis may possibly include the large 

 northern form N. clausa ; that figured by him as N. affinis is undoubtedly the smaller species. 



