MOLLUSCA. 57 



Section II. MOLLUSCA (proper). 



The Mollusca are chiefly procured by dredging, examina- 

 tion between tide-marks, or the deep-sea lines of the fisher- 

 men, though certain storms sometimes strew the sands with 

 many species in great profusion. Not a few of the rarer forms 

 are found in the stomachs of fishes, such as the cod, haddock, 

 and flounder. The remarks on the class may be arranged in 

 three divisions, founded on the economical value, peculiar 

 habits, and rarity. 



By far the most important species in the first group is the 

 common mussel (Mytilus edulis), which occurs in vast numbers 

 in the form of mussel-" beds " on muddy flats, chiefly situated 

 on the right bank of the estuary of the river Eden. Attached 

 to stones, sticks, and to each other, these shell-fish luxuriate 

 in abundance of Diatomacea?, Infusoria, and other minute 

 forms of animal and vegetable life. From their special value 

 as bait the city derives a considerable annual revenue ; and if 

 the wise protection only lately enforced were supplemented by 

 skilful mussel-farming, great increase in revenue might be 

 anticipated. Shell-fish, like other animals in civilized parts, 

 cannot survive constant inroads without special restrictions. 

 Multitudes of the young mollusks, moreover, are found in- 

 crusting the poles for the salmon-nets on the West Sands, and 

 the rocks, stones, and tangle-roots elsewhere ; but they do not 

 attain a large size, apparently from overcrowding and the want 

 of congenial food, which the purer water seems incapable of 

 supplying. This species takes the place of the horse-mussel 

 ("yoags ") of the Zetlandic fishermen, and the worms of those 

 in the Channel Islands. It is seldom eaten by the natives. The 

 edible cockles, again, abound on the sandy flats near the 

 entrance of the Eden into the sea, and are occasionally sold as 

 food, though of late years their scarcity has rendered their 

 appearance less frequent in the market. Periwinkles and 

 limpets are constantly gathered for similar purposes. The 



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