78 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [372] 
quite peculiar, and when it is fully extended it has a singular appear. 
ance. The general color is usually orange-brown, and it is thickly 
speckled with darker brown. This shell is devoured in large numbers 
by the flounders, and doubtless by other fishes. 
A number of species which habitually live clinging to eel-grass are 
to be found in the localities where this plant flourishes, either in the 
pools or at low-water mark, but they are not peculiar to or character- 
istic of muddy shores. Among these the most common are Astyris 
lunata, (p. 306 ;) Bittium nigrum, (p. 305 ;) Triforis nigrocinetus, (p. 305;) 
and Lacuna vincta, (p. 305.) The Littorina irrorata is occasionally 
found in sheltered situations, but this region is north of its true range, 
and such specimens as are found may have been introduced from far- 
ther south with oysters. It is very abundant on the southern coast. 
The Crosalping cinerea (p. 306) occurs wherever there are beds of oys- | 
ters, upon which it feeds. 
Most of the bivalve shells to be found on muddy shores have already 
been enumerated as living also on the sheltered sandy shores, and the 
majority of them flourish equally on both kinds of shores, and on those 
of amixed or intermediate character. Among these are Mya arenaria, 
(p. 309;) Macoma fusea, (p. 358;) Angulus tener, (p. 358;) Venus merce- 
narid, (p. 3593) Argina perata, (p. 309 ;) Mytilus edulis, (p. 307 ;) Pecten 
irradians, (p. 361.) There are, however, other species that are almost 
peculiar to muddy shores, and are highly characteristic of them. The 
Pholas truncata (Plate XX VII, fig. 200) excavates deep holes in depos- 
its of tenacious clay at all elevations between tides, and is still more 
frequently found living in holes in the borders of peat-bogs, or marsh 
deposits, which have been encroached upon by the sea. In such places 
they sometimes occur nearly up to the ordinary high-water mark. 
Their holes are round and nearly perpendicular, and increase in size 
from the orifice downward. They vary in depth according to the size 
of the shell; the deeper ones are often a foot or a foot and a half in 
depth and often an inch in diameter. The shell remains near the bot- 
tom and stretches out its long siphon tubes, which are united together 
quite to the end, until the tips reach the external orifice of the burrow 
These tubes are generally yellowish white except at the end, where they 
are blackish or brownish; the orifices and papille are also variously 
marked with purplish brown or dark brown. The dark coloration of 
the end of the siphon tubes is doubtless for purposes of protection from 
predacious fishes, crabs, &c. Its foot is short and stout, obliquely trun- 
cated, and bevelled at the end. The Petricola pholadiformis (Plate 
XXVHU, fig. 199) is generally associated with the preceding species and 
is more abundant. Its habits are nearly the same, but it does not make 
its burrows so deep; it is more active in its motions, and can easily 
climb up to the upper part of its hole by means of its long, thin, white 
foot, which is tongue-shaped and very extensible and flexible. The 
siphon-tubes are long and slender, tapering, and united for about a 
