found on the coast of Northumberland and of Durham. 339 



undaium with an unusually thin shell, a remarkably short spire, 

 and very tumid whorls, inhabiting a '^ mussel scarp '' at a depth 

 of from a foot to about two fathoms below low water mark, 

 within the entrance of the river Tees. I have hitherto been 

 disposed to regard this form as a distinct variety ; and probably 

 it would have been described as such in my paper had not cir- 

 cumstances prevented me : I now consider however that it is 

 merely a thin form of littorale ; and hence my reason for extend- 

 ing the vertical range of this variety to the Laminarian zone. 



The Tees form of littorale is exceedingly interesting on account 

 of its confirming an opinion of Mr. J. E. Gray, that '^ 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*.^-' It cannot be denied, that the ocean at great depths 

 is " still,^' and that it is inhabited by thin varieties, pelagicum for 

 example : whether the shell figui'ed by Pennant as the Buccinum 

 striatum was obtained from the " still water " of the ocean or 

 " of harbours," I cannot say ; but I am quite certain, that the 



lisliing on the subject, as soon as he became satisfied as to the correctness of his 

 views : it tvas on this contingency that I understood his publishing to depend. 

 What I was unacquainted with at the time, was the negative character just 

 mentioned of the variety crasAwm — having been previously led to think that 

 the epidermis was worn off: this is the only point I will concede to Mr. 

 Hancock, and as such it is duly acknowledged in my paper. 



Five years after the subject had been introduced between us, and finding 

 it necessary to describe my n^w acquisitions, and conceiving that my views 

 respecting the number of varieties of Buccinum undatum belonging to our 

 coasts, and the essential characters of these varieties, were different from 

 those I had seen or heard described, I commenced my paper, without ever 

 thinking,|that in publishing these views I should be interfering with the 

 publication of Mr. Hancock's, particularly when the publication of the latter 

 depended on a contingency which I saw little or no chance of ever hap- 

 pening. My surprise is certainly great, that Mr. Hancock, after my paper 

 was published, and after leaning to a contrary opinion for nearly six years 

 (up to last August for a certainty), should now " feel satisfied " that his 

 three varieties are ** mere varieties." 



My paper, as it was read at the British Association, contained the descrip- 

 tion given in the text of the variety crassum, a.\so iin acknowledgement to the 

 effect that it was Mr. Hancock to whom I was indebted for the information 

 of its generally being without an epidermis : the descriptive part, I regret, 

 was afterwards cancelled : 1 was very reluctant to do this at the time, as I 

 felt that this gentleman had no more exclusive right to describe this variety 

 than he had to describe littorale and magnum, inasmuch as all three had 

 been previously either described or figured by Lister, Pennant, Dr. Johnston 

 and others : nor could I conceive, that his informing me of the general ab- 

 sence of the epidermis in the case of crassum prevented me describing it or 

 any of the others. 



* Philosophical Transactions, 1833, p. 784. 



24* 



