They are somewhat remote from the sea mussels in structure, and have not even a common economic importance.
The sheltered waters of the broken southern coast, however, are rich in fish and molluscs, especially in mussels, limpets and barnacles, which are the principal food resource of the nomadic Indian tribes of those regions.
Such movement is more frequent in young mussels than in the full-grown.
The annual value of the shell-fish (lobsters, crabs, oysters, mussels, clams, periwinkles, cockles, shrimps) is about £73,000.
These cod are fed chiefly on mussels, and when the keeper approaches to feed them they may be seen rising to the surface in hundreds and eagerly seeking the edge.
The production of pearls by oysters and mussels is common knowledge, but it is only recently that the origin of pearls has been traced and admitted to be due to inflammation set up by a parasite.
They are ridges of aeolian limestone plastered over by a thin layer of corals and other calcareous organisms. The very remarkable "serpuline atolls" are covered by a solid crust made of the convoluted tubes of serpulae and Vermetus, together with barnacles, mussels, nullipores, corallines and some true incrusting corals.
L * An independent anatomical investigation of the Mollusca had been carried on by the remarkable Neapolitan naturalist Poli (1791), whose researches 2 were not published until after his death (1817), and were followed by the beautiful works of another Neapolitan zoologist, the illustrious Delle Chiaje.3 The embranchement or sub-kingdom Mollusca, as defined by Cuvier, included the following classes of shellfish: (1) the cuttles or poulps, under the name Cephalopoda; (2) the snails, whelks and slugs, both terrestrial and marine, under the name Gastropoda; (3) the sea-butterflies or winged-snails, under the name Pteropoda; (4) the clams, mussels and oysters, under the name Acephala; (5) the lamp-shells, under the name Brachiopoda; (6) the seasquirts or ascidians, under the name Nuda; and (7) the barnacles and sea-acorns, under the name Cirrhopoda.
Oysters and mussels are obtained on the East Scheldt, and anchovies at Bergen-op-Zoom; while salmon, perch and pike are caught in the Maas, the Lek and the New Merwede.
Although the anti-toxins which are used in the cure of infective diseases are not dangerous to life, yet they sometimes cause unpleasant consequences, more especially an urticarial eruption almost exactly like that which follows eating mussels or other shell-fish.
In 1873 the value of mussels exported from Antwerp alone to Paris to be used as human food was £280,000.
Twenty-eight boats engaged in haddock-fishing at Eyemouth used between October 1882 and May 1883 920 tons of mussels (about 47,000,000 individuals), costing nearly £1800 to the fishermen, about one-half of which sum was expended on the carriage of the mussels.
The quantity of mussels landed on Scottish coasts has decreased in recent years owing to the decline in the line fisheries.
In the statistics for England and Wales mussels are not separately distinguished.
Experiments made by removing mussels from salt water to brackish, and finally to quite fresh water show that it is even more tolerant of fresh water than the oyster; of thirty mussels so transferred all were alive after fifteen days.
The fresh-water Mussels, Anodonta cygnea, Unio pictorum, and Unio margaritiferus belong to the order Eulamellibranchia of Lamellibranch Molluscs, in which the anterior and posterior adductor muscles are equally developed.
The genital papilla of the female acquires a great development during the breeding season and becomes produced into a tube nearly as long as the fish itself; this acts as an ovipositor by means of which the comparatively few and large eggs (3 millimetres in diameter) are introduced through the gaping valves between the branchiae of pond mussels (Unio and Anodonta), where, after being inseminated, they undergo their development, the fry leaving their host about a month later.
Over 40 species of freshwater mussels (Unionidae) have been observed in the Rumanian rivers.
It is commonly supposed to be capable of prizing limpets from their rock, and of opening the shells of mussels; but, though undoubtedly it feeds on both, further evidence as to the way in which it procures them is desirable.
They do not feed on fish, like true otters, but on clams, mussels, sea-urchins and crabs; and the female brings forth but a single young one at a time, apparently at any season of the year.
There are also a clean race of frogs and tortoises, and a few mussels in it; muskrats and minks leave their traces about it, and occasionally a travelling mud-turtle visits it.
Its original name is said to have been Eskmouth, its present one being derived from a bed of mussels at the mouth of the river.
Musculus, diminutive of mus, mouse, applied to small sea fish and mussels), a term applied in England to two families of Lamellibranch Molluscs - the marine Mytilacea, of which the edible mussel, Mytilus edulis, is the representative; and the fresh-water Unionidae, of which the river mussel, Unio pictorum, and the swan mussel, Anodonta cygnea, are the common British examples.
Many thousand tons of mussels are wastefully employed as manure by the farmers on lands adjoining scalp-producing coasts, as in Lancashire and Norfolk, three half-pence a bushel being the price quoted in such cases.