NATICA. 333 



a faint trace of one or two of the articulated zones is clearly 

 perceptible ; the pillar lip is white, but there is an isolated 

 stain or two of chestnut round the umbilicus. The next 

 resembles the preceding in other respects, but is perfectly 

 devoid of all brown markings, and of a flesh-colour that 

 changes into white at the base of the body-whorl. The 

 typical nitida is of a pure uniform and highly lustrous 

 white : it is very rare, but is occasionally taken alive on 

 different parts of our coast. 



The animal is of a wan yellowish white hue, speckled 

 with tawny spots of various dimensions, and more or less 

 elongated and streaky in form. These are most numerous 

 on the reflexed lobe of the mentum, and on the central 

 portion of the tail. There is no defined coloured border 

 to the mentum. The sole of the foot is white, tinged with 

 tawny. The tentacula are linear lanceolate, white, with 

 acute tawny tips, the orange or tawny colour of their edges 

 being traversed by a white line. In a colourless or albino 

 variety, taken in the Zetland seas, the animal had 

 scarcely a trace of coloured markings. The operculum is 

 corneous. 



This is one of our prettiest and commonest British 

 shells. It ranges throughout our seas, living on all kinds 

 of ground, and ranging from four to as deep as eighty 

 and ninety fathoms. Mr. Alder has found it near Ar- 

 drossan in sand at low-water mark. It inhabits the coast 

 of Europe from Gibraltar to Bergen. In the British area 



(Test. Brit. Suppl. p. ISO), believing it identical, referred to as " not unfrequent 

 amongst parcels of Occidental shells." Maton and Rackett (Trans. Linn. Soc. 

 vol. viii. p. 225), fancying that Donovan's Caithness shell was the mammilla of 

 LinnreuR, substituted that name and copied their description of that imperforated 

 Oriental species from the " Museum Ulricse." Turton {Ner. mammilla. Conch. 

 Diction, p. 125) acquiescing in this decision, mixing the umbilical characters of 

 the two shells, describes the perforation as " nearly or quite closed." 



