300 MURICID.E. 



are sometimes deposited on the under side of the ma- 

 ternal shell ; the base of their attachment is narrower 

 than the upper portion. The shell is known among the 

 Staithes fishermen as the " white whelk." Its home 

 appears to be the German Ocean and the Nymph bank, 

 instead of the arctic seas. Mr. S. Wood's speculation 

 as to the reason why fossil are more distinctly striated 

 than recent specimens is ingenious. He took for granted 

 that the species is " dying out/'' and suggested that the 

 faint and imperfect strise on the shells of the surviving 

 race may be "from failure of vigour in those organs 

 necessary for such distinction, consequent upon the 

 approaching demise of the species." Some of the Crag 

 specimens, however, are not less smooth than recent 

 ones, and were described by Sowerby as his variety 

 " (a), ventricose, rarely sulcated." 



It is the Buccinum ovum of Turton (not Tritonium 

 ovum of Middendorff ) , and probably B. crassum of Nyst; 

 the young was described by Macgillivray as Halia 

 Flemingiana. 



Genus II. TRITON*, De Montfort. PI. V. f. 4. 



Shell thick, each whorl strengthened lengthwise by a vari- 

 cose rib : epidermis skin-like : spire bluntly pointed : outer Up 

 and pillar plaited or tnberculated : canal rather short, open 

 throughout, and nearly straight: operculum oval or oblong; 

 nucleus placed at the outer base of the month. 



The two fine species which I now give as addi- 

 tions to our mollusca inhabit that part of the sea which 

 washes the extreme southern coast of England. Those 

 who reject Haliotis because it has not been found north 

 of Guernsey would of course consider the Tritones and 

 a few species of other genera extra-British. With such 



* The name of a mythological sea-god. 



