178 REPORT OF COMMISSIONER OF FISH AND FISHERIES [472] 



Lamellibranchs. 



Page. 



Pholas truncata 470 



P. costata , . . . 433 



Mya arenaria 469 



Macoma fusca 469 



Tellina tenta 470 



Angulustener 358 



Tagelus gibba 470 



Petricola pholadiformis 470 



Callista convexa 470 



Mulinia lateralis 470 



.Solenomya velum 470 



Nucula proxima 432 



Argina pexata 309 



Modiola plicatula 469 



M. hamatus 374 



Mytilus edulis 470 



Venus mercenaria 469 Ostraea Virgininna 310 



III. 3. ANIMALS INHABITING OYSTER-BEDS IN BRACKISH WATERS. 



Although the oyster-beds are generally planted on bottoms that were 

 originally muddy, when covered wholly or partially with living oysters or 

 with dead oyster- shells, such bottoms may properly be regarded as "shelly 

 bottoms" analogous to the natural shelly bottoms of the outer waters. 

 The shells of the oysters afford suitable attachment for various shells, 

 bryozoa, ascidians, hydroids, sponges, &c., which could not otherwise 

 maintain their existence on muddy bottoms, while other kinds of ani- 

 mals, such as crab s, annelids, &c., find shelter beneath the shells or in 

 their interstices. Some species have apparently been introduced from, 

 farther south with the oysters ; among these are Modiola liamatm and 

 Panopeus Herbstii, neither of which is positively known to be fully nat- 

 uralized on our shores. 



In planting the oysters they are more or less uniformly scattered over, 

 the bottom, from somewhat above low-water mark to the depth of ten 

 or twelve feet. The oysters thus planted are brought mostly from the 

 waters of Virginia and Maryland in spring. During the summer they 

 usually increase greatly in size, and often become very fat and improve in 

 flavor. They are taken up in the fall, for if left exposed to the freezing 

 weather of our winters, at least all those in very shallow water would be 

 killed. They often double in bulk during the summer. Besides the im- 

 mense quantities of oysters thus brought from farther south to be " plant- 

 ed" in our waters, large quantities of young " natives" are also collected 

 from the localities where they naturally breed, and are planted on muddy 

 bottoms in the brackish waters, where they grow very rapidly, usually 

 attaining a size suitable for the market in two or three years. 



These " native oysters," although of the same species as those brought 

 from the south, are more hardy, and will live through the winter if cov- 

 ered by a depth of water sufficient to prevent them from freezing. The 

 young oysters that attach themselves to stones, ledges, &c., between 

 tides, often in great abundance, nearly all perish by freezing during the 

 winter. They mostly become an inch to an inch and a half in diameter 

 during the first summer. The period of spawning lasts for some time, 



