Mr. A. Hancock^s Notes on Buccinum undatum. 151 



tions and striae, that the surface of the shell in this species can- 

 not be depended on, whether these three varieties are to be con- 

 sidered specifically distinct or not ; but that failing the animal 

 we must look to the columella and mouth, and of course to the 

 general form and habit,. for specific characters. Keeping this in 

 view, I have drawn together the following notes, which I trust 

 may assist in elucidating this intricate species. 



I find by a recent number of the ' Annals,^ that Mr. Wm. King 

 has described these three varieties, giving an account of their lo- 

 calities and general habits as I pointed them out to him, shortly 

 after I had commenced the examination of the species. I was 

 rather surprised at this, particularly in respect of the coarse va-. 

 riety without an epidermis, and the shore variety, as I believe he 

 had never collected these two forms himself, nor has he ever posn 

 sessed a sufficient number of them to illustrate their peculiar 

 modifications and the permanency of their characters, and as he 

 was aware that I was about to publish on the subject. He how- 

 ever commits an error, when he states that the shore variety is 

 only found on rocks and pebbly bottoms. Had he attained an 

 accurate knowledge of the subject, such as might be derived from 

 personal experience on the coast of Northumberland, he must 

 have known that it also occurs on mud. 



It has been stated by Mr. Gray, that "the thickness, the 

 roughness, and the smoothness of the surface of shells appear to 

 depend, in a great measure, on the stillness or agitated state of 

 the water which they inhabit. The species of our own coast,'' 

 that gentleman says, " afford abundant instances of this : the 

 shells of Buccinum undatum and B, striatum of Pennant have no 

 other difference, than that the one has been formed in rough 

 water, and is consequently thick, solid and heavy ; and the other 

 in still water of harbours, where it becomes light, smooth, and 

 often coloured." 



This is scarcely corroborated by what is observed on the North- 

 umberland coast : there, the thickest and roughest forms are from 

 twenty fathoms water, and the thinnest and smoothest from much 

 greater depths. In both these cases the water is probably less 

 agitated than in harbours, where the depth is generally much less. 

 The third variety, however, which is intermediate in coarseness 

 and thickness, is procured between tide-marks, and consequently 

 subjected to the most violent action of the sea. The thin delicate 

 specimens are, I believe, always found on a soft sandy or muddy 

 bottom, and the strong rough individuals on hard or rocky 

 ground. It is therefore probable that the food, varying in loca- 

 lities so different, may modify development. The three principal 

 varieties themselves undergo considerable change on different 

 grounds, irrespective of depth. Thus the beach variety on rocks 



