LEBOUR : [variation IN] RADUL.E OF BUCCINID^. 283 



may be of some interest, although they go over much the same ground 

 that Friele has aheady investigated so thoroughly, both in the above- 

 mentioned paper and in the " Norske Nordhavs Expedition," his 

 illustrations in both papers being most profuse. I have not here 

 figured any radulse of the genus Buccinum. 



As was to be expected, there appears to be no correlation of 

 variation with regard to the shell and the radula. Forty-eight speci- 

 mens of Buccinum iindatiDu from the North Sea, eighty miles E. by N. 

 of the river Tyne, were examined ; thirty female and eighteen male. 

 Twenty-three of these had a normal radula {i.e., laterals four, centrals 

 six), seventeen of which were females. The other twenty-five varied 

 as follows : — 



(1 monstrous). 



7 - 5 4 - i(?. 



From these numbers it will be seen that about 43 per cent, only 

 are normal. The females do not vary so much as the males, and 

 chiefly only in the centrals. The most frequent variation is seven 

 centrals instead of six ; indeed, so common is this that Gray regarded 



