360 EEP0RT^5H^r)MMISSI0NER OF FISH AND FISHERIES. 



more or less mottled and streaked with dark brown, aud sometimes with 

 opaque white. 



This species is taken in large quantities for food, and may almost al- 

 ways be seen of various sizes in ou^ markets. The small or moderate- 

 sized ones are generally preferred to the full-grown clams. Most of 

 those sold come from the muddy estuaries, in shallow water, and are 

 fished up chiefly by means of long tongs and rakes, such as are often used 

 for obtaining oysters. Sometimes they are dredged, and occasionally 

 they can be obtained by hand at or just below low-water mark. These 

 estuary specimens usually have rough, thick, dull-white, or mud-stained 

 shells, but those from the sandy shores outside have thinner and more 

 delicate shells, often with high, thin ribs, especially when young j and 

 in some varieties the shell is handsomely marked with angular or zig- 

 zag lines or streaks of red or brown, (var. notata.) These varieties 

 often appear so different from the ordinary estuary shells that many 

 writers have described them as distinct species, but intermediate styles 

 also occur. This species is very abundant along the coast from Cape 

 Cod to Florida; north of Cape Cod it is comparatively rare and local- 

 It does not occur on the coast of Maine or in the Bay of Fundy, except 

 in a few special localities, in small, sheltered bays, where the water is 

 shallow and warm, as at Quahog Bay, near Portland 5 but in the south- 

 ern parts of the Gulf of Saint Lawrence, as about Prince Edward's 

 Island and the opposite coast of Nova Scotia, where the water is shal- 

 low and much warmer than on the coast of Maine, this species again 

 occurs in some abundance, associated, in the same waters, with the 

 oyster and many other southern species that are also absent from the 

 northern coasts of I^ew England, and constituting a genuine southern 

 colony, surrounded on all sides, both north and south, by the boreal 

 fauna. 



The curious aud delicate shell called Sohnomya velum (Plate XXIX, 

 fig. 210) is occasionally found burrowing in the pure, fine, siliceous sand 

 near low- water mark, about two inches below the surface, but its proper 

 home is in shallow- water, beyond low-water mark, aud it is, perhaps 

 most abundant where there is mud mixed with sand, and it also lives 

 in soft mud. Its shell is glossy and of a beautiful brown color, and is 

 very thin, flexible, and almost parchment-like in texture, especially at 

 the edges. It is a very active species, aud has a very curious foot, 

 which is protruded from the front end of the shell, and can be used in 

 burrowing, very much as the " razor-shell," described above, uses its foot ; 

 but the Solenomya makes use of its foot in another way, for it can swim 

 quite rapidly through the water, leaving the bottom entirely, by means 

 of the same organ. The foot can be expanded into a concave disk or 

 nmbrella-like form at the end, and, by suddenly protruding the foot 

 and expanding it at the same time, a backward motion is obtained by 

 the reaction agaiust the water ; or, by suddenly withdrawing the foot 

 and allowing it to remain expanded during most of the stroke, a for- 



