found on the coast of Northumberland and of Durham. 249 



can be little doubt that it lives on a muddy bottom : the largest 

 and thickest specimens are from the shallowest water. The New- 

 castle museum possesses an aberrant form of this variety without 

 the least trace of waves, and resembling the Buccinum carinatum 

 of Turton. 



Variety Buccinum pelagica. — In speaking of the last variety it 

 was stated, that the thickest specimens were from the shallowest 

 water, that is from fifteen to twenty-five fathoms, and, as implied, 

 that the thinner kinds were from a greater depth, say from twenty- 

 five to forty fathoms : the same variation is observable in the va- 

 riety under consideration ; the thickest specimens are to be found 

 in from forty to fifty-five fathoms, while the thinnest live in from 

 fifty-five to eighty fathoms. In short, there is an unbroken gra- 

 dation of character from the very thick shell found in fifteen 

 fathoms water to the excessively thin one which has its habitat in 

 eighty fathoms : but how different is their appearance when they 

 are contrasted ! take for example a full-grown specimen of each 

 variety from the extremes of depth. 



Buccinum magnum var. Buccinum pelagica var. 



4i inches long, 2$ inches broad. 4^ inches long, 2 inches broad. 



Nine whorls. Ten whorls. 



T %ths of an inch in thickness. T ^th of an inch in thickness. 



Spiral cords and threads prominent Spiral cords and threads small and 



and persistent. becoming obsolete on the large 



whorls. 



Epidermis thick and clothy. Epidermis thin and ciliated. 



Waves large and on all the whorls. Waves small and only on the first six 



whorls. 



Both sides of the siphon of the same The columellar side of the siphon 



length. much shorter than the opposite one. 



Weight 3i ounces. Weight £ an ounce. 



I have not yet procured any specimens of Buccinum pelagica 

 without the waves and simply threaded, as appears to be the case 

 with the Buccinum ciliatum of Fabricius, but I have some closely 

 approximating to this species in these respects : in a few of my 

 specimens the waves lose their peculiarity, and become simple 

 longitudinal plications, not in the least undated. If Buccinum 

 ciliatum occurred on our coast, I should be strongly inclined to 

 regard it as another variety. 



Buccinum pelagica has a strong tendency to become elongated : 

 I have specimens closely resembling the shell figured by Donovan 

 as the Buccinum glaciate * (the same shell has been named Buc- 

 cinum Donovani by Mr. J. E. Gray). Its colour is extremely va- 

 riable, being externally white, variously shaded with brown, yel- 

 lowish, and often marked with two or more reddish brown or 

 purple bands : owing to its thinness, the outside colours are often 



* British Shells, pi. cliv. 

 Ann. fy Mag:N. Hist. Vol. xviii. T 



