MR HARMER ON FUSUS ANTIQUUS. 223 



aware that either of the sinistral forms mentioned has been 

 dredged Hving north of Vigo Ba.y\ Neither Gwyn Jeffreys^, nor 

 McAndrew'', whose investigations extended from the Canaries to 

 the North Cape, and were carried on during many years, knew of 

 any more northern locaHty for them. At Vigo, however, it is 

 stated b\^ the latter, specimens of Fusits contrariiis are moderately 

 abundant. 



The dextral forms, on the contrary, are all northern. Neptiinea 

 ajitiqua is Scandinavian as well as British, but it does not range far 

 to the south of our shores. Its carinated allies, N. carinata and 

 A^. despccta, are characteristically boreal, or even arctic, being 

 common in the extreme north of Norway, Russia, and Greenland*. 

 McAndrew says that all the specimens of Fnsiis antiqmis obtained 

 by him in Norway were carinated ^ 



Referring to their former distribution, we find that none but 

 sinistral species occur as fossils in the south of Europe, although 

 during the later Tertiary period such forms extended further to 

 the north than they do at present. They are found in later 

 Pliocene beds on both sides of the North Sea basin, viz. in the 

 East Anglian Crag and the Scaldisien deposits of Holland and 

 Belgium in one direction, and in another at Wexford, on the Irish 

 coast®, and in Kintire in Scotland'. 



On the other hand, the dextral species are unknown from any 

 of the Pliocene strata of France, or of the Mediterranean, but they 

 are common at all the later horizons of the English Crag beds. 



Neptuiica contraria is now a southern form, although it seems 

 probable that it originated, as did its dextral congeners, in northern 

 seas, at a time when the climate of northern Europe was warmer 

 than it is at present, and that both groups invaded the Anglo- 

 Belgian Pliocene basin from the north. No trace of the existence 

 of representatives of either, dextral or sinistral, has been found in 

 the earlier Pliocene deposits of Belgium, England or Normandy, 

 nor is any species known from these or any older strata which can 

 be regarded as an ancestral form^ 



The arrival of Neptunea contraria in these latitudes preceded, 

 however, that of its right-handed representatives. In the Scaldisien 

 deposits of Belgium, and in the oldest part of the Red Crag of 

 England, viz. that of Walton-on-Naze, contemporaneous with 



^ Reversed specimens of Neptunea an/iqiia are very occasionally met with on the 

 English coast, but except that they are left-handed, they cannot be distinguished from the 

 right-handed shells among which they occur. The sinistral forms of Vigo Bay are, on the 

 contrary, materially different from the dextral species of British or Arctic seas. 



- Brit. Conch, vol. iv. p. 326. 



* Reports Brit. Assoc., 1856, p. 131. 



^ Sars, £^iin. Nc7o Phil. Soc, July 1863. 



^ Loc. cit., p. 131. 



^ Forbes, Mem. Geo/. Survey, vol. I. p. 91. 



" Reports Brit. Assoc, 1896, p. 390. 



8 See also G. F. DoUfus, Soc. Roy. Malac. de Bclgique, t. xvni. 1883. 



