LITTORINA. 31 



rarely the entire mouth is white. The larger of the 

 specimens we have delineated is fully the average size 

 of fine individuals. As a general rule, it may be remarked 

 that in the banded varieties of this and rudis, the colour- 

 ing-matter is usually disposed in narrow rings in the 

 former, in broad zones in the latter. The outer lip, 

 in the present species, is more frequently margined in- 

 ternally with the darker external colouring ; in rudis, 

 it is more apt to be pallid, or tinged with orange- 

 yellow. 



The animal above is of a general dark hue, arising 

 from close-set brownish-black linear markings on a yel- 

 lowish or tawny ground. The lanceolate tentacula are 

 irregularly ringed with these markings, as is the muzzle 

 also. The operculigerous lobe is rounded, pale, and 

 tawny, with few markings. The sole of the foot is 

 yellowish-white. Loven describes the tongue as having 

 broad and quadrate central teeth, with strongly inflexed 

 apices, consisting of a cordate central lobule, flanked by 

 obtuse denticulations on each side : the uncini are nearly 

 all alike, thick, and have unequally lobed and toothed 

 apices. 



This is pre-eminently the " Periwinkle ^ of our shores, 

 a name said to be a corruption of petty winkle. Mr. 

 Searles Wood says that they are called "Pinpatehes" 

 in SuiFolk. Great quantities are sold in London, and 

 eaten on many parts of our coast, after being boiled, when 

 the animal is extracted by means of a pin. It is a poor 

 man's delicacy, but by no means to be despised. It 

 inhabits the third sub-region of the littoral zone,* or belt, 

 between tide-marks, that of which Fucus articulatus and 

 F. nodosus are the characteristic plants, and is found 



* See Memoirs of the Geol. Survey of Great Britain, vol. i. p. 373. 



