11. THE NATURAL HISTORY OF THE OYSTER. 



U. GENERAL NATURAL HISTORY. 



60. THE GROWTH AND HABITS OF THE AMERICAN OYSTER OF THE ATLANTIC COAST. 



Number of species on the Atlantic coast. — Tlie qnestiou of the specific unity of all the oysters of our 

 Atlantic coast has probably been placed beyond dispute now, and it is settled that the name Ostrca virginiana 

 includes the whole. Says Verrill, in his Invertebrates of Vineyard Sound: 



All the various forms of this species, upon whicli the several nominal species, united above, have heen based by Lamarck and 

 others, often occur together iu the same beds in Long Island sound, and may easily be connected together by all sorts of intermediate 

 forms. Even the same specimen will often have the form of horealis in one stage of its growth, and then will suddenly cha';ge to tho 

 rU-gMana style, and, perhaps, later still, will return to the form of lorealis. Or these different forms may be assumed in reverse order. 

 Great variations in the number and size of the costie and undulations of the lower valve occur, both in ditt'erent specimens from the same 

 locality, and even iu the same specimen, at ditt'erent stages of growth. All these va,riationa occur in precisely the same way in the shells 

 taken from the ancient Indian shell-heaps along our entire coast, from Florida to Maine. 



In another place he alleges : 



I am unable to find any specific differences between tho northern and southern oysters, such differences as do exist being due merely 

 to the circumstances under which they grow, such as the character of the water, abundance or scarcity of food, kind of objects to which 

 they are attached, age, crowded condition, etc. All the forms occur both among the northern and southern ones, for they vary from, 

 liroad and round to very long and narrow ; from very thick to very thin ; and iu the character of the surface, some being regularly ribbed 

 and scalloped, others nearly smooth, and others very rough and irregular, or scaly, etc. When young and grown under favorable 

 conditions, with plenty of room, the form is generally round at first, then quite regularly oval, with an undulated and scalloped edge and 

 radiating ridges, corresponding to the scallops, and often extending ont into spine-like projections on the lower valve. The upper valve 

 is flatter, smooth at first, then with regular lamella? or scales, scalloped at the edges, showing the stages of growth. La^er in life, 

 especially after the first winter, the growth becomes more irregular and the form less symmetrical; and the irregularity increases with 

 the age. Very old specimens, in crowded beds, usually become very much elongated, being often more than a foot long, and perhaps 

 two inches wide.* In the natural order of things this was probably the normal form attained by the adult individuals, for nearly all the 

 oyster-shells composing the ancient Indian shell-heaps along our coast are of this much-elongated kind. Nowadays the oysters seldom 

 have a chance to grow to such a good old age as to take this form, though such are occasionally met with in deep water. The young 

 specimens on the rocks are generally mottled or irregularly radiated with brown. 



Geogeaphical distribution. — The geographical distribution of the oyster along our coast has already been 

 learned in detail, and need only be sketched. It is to be found almost without interruption — except at wholly 

 unsuitable localities — from Florida, and the northern shores of the Gulf of Mexico, to Massachusetts bay; local 

 farther north, off Uamariscotta, Maine, and in the southern part of the Gulf of St. Lawrence, at Prince Edward 

 island, in Northumberland straits, and bay of Chaleur. " Not found along the eastern .shores of Maine, nor in the 

 bay of Fundy. Abundant in the ancient Indian shell-heaps on the coast of Massachusetts, on the i.slands in Casco 

 bay, and at Damariscotta. The shells, in a semi-fosyil state, have been dug up from deep beneath the mud in the 

 harbor of Portland, Maine, iu large quantities, but native oysters appear to be entirely extinct in Casco bay. Very 

 abundant in Long Island sound; in the upper part of Buzzard's bay; rare and local in Vineyard sound; very 

 iibundant on the shores of Maryland and Virginia. I\Iouth of St. John's river, and in Tampa bay, Florida 

 (Conrad). Texas (llosmer)." 



Fossil oysters. — In the history of the world, as .shown by the record of the rocks, the oyster has long played 

 a part. The oldest fossil of this family kuown was discovered by Professor Winchell in carboniferous strata, and 



* "The large oyster taken by Xavier Franfois, while oystering on Monday last, was brought up from the wharf on a dray last evening. 

 An oyster measuring 3 feet I iuch in length, and 234 inches across the widest part of it, is a curiosity."— J/otiVc (Ala.) liiijMtr, April, 

 1840. 



"An East river oyster," says De Voe, " was opened by Braisted, of Jefferson market, New York, January 27, ld6."), which contained a 

 butter-fish \_Poronotun triacantliuaf'] measuring 6 inches in length. It was quite dead." 



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