The filaments of the gill (ctenidium) of Mytilus and Arca thus form two closely set rows which depend from the axis of the gill like two parallel plates.
That the level of Lake Aral was much higher in postPliocene times is proved by the discovery of shells of its characteristic species of Pecten and Mytilus in the Kara-kum Desert, 33 m.
In Mytilus the foot is reduced to little more than a tubercle carrying the apertures of these glands.
II, C. Now let us suppose as happens in the genus Dreissensia - a genus not far removed from Mytilus - that the ciliated inter-filamentar junctions (fig.
The organs are developed as invaginations of the epidermis of the foot, and in the majority of the Protobranchia the orifice of invagination remains open throughout life; this is also the case in Mytilus including the common mussel.
In Mytilus the two apertures are on a common papilla, in other cases the two apertures are as in Anodonta.
This was manufactured from the Mytilus californianus, a mussel which abounds there.
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.
Then let us suppose that the inter-lamellar junctions already noted in Mytilus become very numerous, large and irregular; by them the two trellis-works of filaments would be united so as to leave only a sponge-like set of spaces between them.
It is a curious fact, illustrative of the ignorant procedure and arbitrary fashions of fisher-folk, that on the Atlantic seaboard of the United States the sea mussel, Mytilus edulis, though common, is not used as bait nor as food.