372 REPORT^i^COMMISKSIONER OF FISH AND FISHERIES. 



quite peculiar, and when it is fully extended it has a siugulai appear- 

 ance. The general color is usually orange-brown, and it is thickly 

 speckled with darker browu. 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. 30G;) Bitilum nif/rwuj (p. 305;) Tri/oris nigyocbictus, (p. 305;) 

 and Lacuna vincta, (p. 305.) The LUtorina 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 Urosalpinx cinerea (p. 300) 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 equall}- on both kinds of shores, and on those 

 of a mixed or intermediate character. Among these are Mya arenaria, 

 (p. 309;) Macoma fusca, (p. 358;) Angulus tener, (p. 358;) Venus meree- 

 naria, (p. 359 ;) Argina ])exata^ (p. 309 :) Mytihis edulis, (p. 307 ;) Fecten 

 ■irradians, (p. 3G1.) There are, however, other species that are almost 

 peculiar to muddy shores, and are highly characteristic of them. The 

 Fholas truncata (Plate XXVII, 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 papilhe are also variously 

 marked with purplish brown or dark brown. The dark coloration of 

 the end of the siphon tubes is doubtless for imrposes of protection from 

 X)redacious fishes, crabs, &c. Its foot is short and stout, obliquely trun- 

 cated, and bevelled at the end. The Petricola pholad if onnis (Plate 

 XXVII, fig. 1D9) 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 

 sij)hon-tubes are long and slender, tapering, and united for about a 



