G. Brown (George Brown) Goode.

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found insufficient to prevent their attacks, for piles thus treated at Christiania were found by Mr.
Jeffreys to be filled with the Teredo within two years after they were put down.

" Several other species of Teredo also occur on this coast. The Teredo megotara has been found
in floating pine wood at Newport, Rhode Island, and in cedar buoys, etc., at New Bedford, Massa-
chusetts; as well as in Massachusetts Bay, at Provincetown, and other places; it is also found as
far south as South Carolina at least. This species sometimes grows to a large size, forming tubes
at least eighteen inches long. It sometimes occurs, also, in the piles of wharves in this region.



THE CLAMS. 707

[Vineyard Sound, Massachusetts]. The Teredo Thornton* has been found in great numtars in
the marine railway and also in cedar buoys at New Bedford. It has also been found at
Provincetown in a whaling-ship that had cruised in the West Indies.

"Tin- .\'i/l<>tri/<t jimbriata is very similar to the common Toredo, except that it has long, oar-
shaped pallets, with slender stalks ; the blade is flattened on the inside and convex externally,
and consists of ten to twelve or more funnel-shaped segments which set one into another; their
margins project at the sides, making the edges of the blade appear serrated. This species apjiears
to be indigenous on this coast. It has been found living in a sunken wreck in Long Island Sound,
near New Haven, and I have also taken it from the oak timbers of a vessel, the "Peterhoff,"
employed in the blockading service, during the late war, on the coast of the Southern States. It
grows to a rather large size, often forming holes a foot or more in length and a quarter of an inch
in diameter, though usually smaller. The pallets are sometimes half an inch long."

Less likely to be mistaken for worms, but equally clever at boring, is a group of shells colled
Pholads, from the Greek word yw/.lw, lurking. They perforate all substances that are softer than
their own valves, and some that seem to be harder. Woodward says: "It is to be remarked that
the condition of the Pholades is always related to the nature of the material in which they are
found burrowing; in soft sea-beds they attain the largest size and greatest perfection, whilst in
hard and especially gritty rock they are dwarfed in size and all prominent points and ridges
appear worn by friction." The Pholads have white shells, generally very thin but hard and
strong, and adorned with rasp-like sculpture. It was supposed formerly that the excavation was
made by twisting and moving this rough shell in the burrow; but the muscular, club-shaped foot
is no doubt the instrument of abrasion.

We have upon the east coast three species, but none of them are of practical importance.
They might become available for food, however, since the same mollusks are eaten in the southern
counties of England, where they are called "Piddocks," and some cousins (Zirphaa crispata,
Platydon cancellatus, etc.) are esteemed delicacies on the coast of California under the name of
''Date-fish." Other west-coast species (Navea, Qastrochama, etc.) are enemies of the Oyster,
Abalone, and other mollusks which themselves have a commercial importance, since they burrow
into their shells and so ruin them for service to man. There is, nevertheless, an attendant
advantage in this, since in a state of nature the Pholads thus break to pieces and tend to level
reefs that would prove obstructive to navigation, particularly in the case of coral banks. When
the object leveled is an expensive dike or breakwater, however, the result is exactly reversed, as
it is very likely to be where man's arts attempt to change, the natural arrangement of things.

Our Razor-shell (Ensatella amcricana) is frequently used for food in Enro|>e and in New
England, and its valves have occasionally been applied to artistic service. It passes under the
various names of " Razor-fish," " Razor-clam," " Knife-handle," etc., and is enticed from its sandy
burrow by sprinkling salt upon the sand under which it lies, or is rooted out with a spade. John
Josselyn, Gent., records that its " shell, calcinM and pulveriz'd, is excellent to take off a pin and
web, or any kind of filme growing over the eye." The California!! Razor-fish (Siliqmi /><///) is
also edible.

Next upon the list comes the "Soft Clam," "Long Clam," or "Nauninose" (Mya arenaria),
dear to New Englanders and only less numerous than the Hard Clam in the markets of New York
and Philadelphia. This Clam lives just Iteneath the surface of the sand and mud above low-water
mark, and is easily dug out with a hand-shovel. A very large class of persons all along the shore
from Maine to Delaware derive their living wholly or in part by digging it and shipping to city
markets. This is chiefly the case north of New York, however. On the northern coasts of New



708 NATURAL HISTORY OF AQUATIC ANIMALS.

England immense quantities of this bivalve are collected and salted to be used as bait in the
cod fishery. Statistics and a full discussion of the habits and artificial culture of this Chun will
be found in the special chapter devoted to the Clams.

Washed up by storms from the deep sands down at least to ten fathoms below the low-water
line and hence known as the "Beach," "Sea," or "Surf" Clam, the huge Spisula solidissima
furnishes occasional repasts to the dwellers along the whole Atlantic shore. It is chiefly eaten in
Massachusetts, however, and its flesh is tough and by some persons considered unwholesome. It
is often cast up in such great quantities as to become available for manure, mixed with various
other marine animals of all sorts and sizes and much sea-weed. The large, smooth, white valves
are collected in considerable quantities to be decorated inside with pictures in oil or India ink,
which are again sold in the picture stores, often for a good price. This Clam is also preserved as
bait. On the Pacific coast an allied species (Spisula falcata) serves the various purposes to
which the eastern one is applied.

Following this comes the Quahaug ( Venus mercenaria), which is known in the markets as
" Hard Clam," " Round Clam," or, in New York, simply " Clam." From Cape Cod to Florida it is
very abundant, but must be gathered by raking, since it does not burrow in the shore-sands like
the Soft Clam. A commerce still larger than in the case of the Soft Clam is carried on with
this species as bait, and also for food, in which respect it ranks next to the Oyster in the United
States.

On the Pacific coast where eastern shell-fish are constantly sent for transplantation and for
immediate consumption there are various bivalves used as food, such as Semele decisa, the " Flat
Clam"; Macoma nasuta, the "Tellens," of San Francisco; ScMzothcerus Nuttalli, the "Gaper";
Chione succincta, aud allied species, which replace eastern "Little Necks"; and Saxidomus aratus,
to relish which was learned from the Indians.

In regard to this latter mollnsk (Saxidomus aratus) it is interesting to note that its shell was
broken into pieces by the Indians of the California coast and worked into flat, circular disks by
rubbing upon stone. Eighty of these disks strung upon sinews were in recent use by the Indians
of Lake County, California, as a medium of exchange in trade, aud were valued at one dollar. In
Sonoma County Saxidomus gracilis seems to have served the same purpose.

Another form of aboriginal money was made from the valves of the ponderous Hen Clam of
southern California (Pachydesma crassatelloides), already mentioned. This money was called
" hawok," and took the shape of perforated disks which could be strung as beads. The larger
pieces, according to Stearns, were worth twenty-five cents, and were cut from the thicker parts
of the shell ; while the thinner portions supplied beads worth only four cents each. Further
information will be found upon this in my magazine article above referred to.

The Pachydesma and its neighbor, the Cardium Nuttalli, are considered edible by the west
coast people; but on the Atlantic shore, where occur several large species of "Cockle" (as the
members of the genera Cardium, Astarte, Venericardia, and the like, are called), they are rarely or
never used as food. This neglect seems curious, since this inollusk is eaten in great abundance in
England, and may be bought everywhere in London during summer. " Prodigious quantities of
this shell-fish are also consumed in Holland, where their cheapness recommends them to the
common people as a principal article of food during the winter." In New England Cyprina islandica
is eaten now aud then, but bears a poor reputation in comparison with the Quahaug. In the
Southern States the large " Painted Clam " (Callixta giyantca) is equally available as food, and the
Onathodon cuneatus of the Gulf of Mexico is already an article of diet, as well as useful in road-
making, to which utility many other mollusks contribute in all sea-shore towns.



Tin: MTSSKLS. 709

These thick -shelled bivalves disposed of, a large group of thin-shelled mollnsks deserve
not ice. Foremost among these are the Mussels, which are of several kinds. In Europe the Mytilus
nliillx (which is not different from our common Black Mussel of both the east and west coasts) holds
an important place among sea-foods. In 1873 the mussel fishery of France alone was worth over
SOO.iHMi francs . * H'.it.oiMi). In that country they are regularly bred in inclosures of sea-water,
upon frames and hanging ropes constructed for the purpose, and many ]>er8ons are employed.
In Kiigland, Scotland, Ireland, along the Mediterranean, in the West Indies, and along the whole
circumference of South America, edible species of one name or another grow. Our Mytihai ctlitli*
is circmiipolur in its distribution, and is excessively numerous at all rocky point- suitable for its
growth. In New York it is pickled in large quantities and shipped throughout the interior of the
country. Its shells are extensively used by oyster-planters as a cnltch upon which to catch young
Oysters, and when polished are made into paint-holders for artists and various articles of bijouterie
and personal ornament. The American Indians and the native New Zealanders used them as
tweezers in pulling out their beards.

Mussels of a different sort are the Motliola plicatula, the Modiola modiolw, the Mot) Ma hamaiu*,
and Modiola capax; the first two are of the northern Atlantic, the third is more southern, and
the fourth a native of California. These are sometimes eaten, but are not considered so good as
the M. edulis. On the coasts of New Jersey and Long Island, however, incredible quantities are
gathered from the banks at the inlets through the outer teaches where they grow, and are spread
upon sea-shore farms as manure. In gathering this fertilizer a large number of vessels and men
find irregular employment at times when they would otherwise be idle.

Another important bivalve in a commercial way is the Scallop, fisheries for which flourish in
Long Island Sound, Nurragansett Bay, and elsewhere. Large fleets of vessels are engaged in
summer in dredging for these shell-fish. The powerful central muscle by which the animal opens
and closes its shells forms the edible portion, the rest being discarded. These white fragments are
to be seen piled upon platters or strung in strings as a constant delicacy in all our markets. The
common Scallop of commerce is the Pecten irradians. Years ago the very large species, Pecten
ixlandicii*, an inhabitant of Eastern Maine and the Bay of Fuudy, used to be obtained, and was
highly prized for its flavor, but it has long been too rare to serve any purpose other than as a
curiosity to conchologists. A more common and useful species, north of Cape Cod, is Pciten tenui-
costatus, which supplied the Indians with a culinary instrument, and is good food.

" Scallop shells were formerly worn by pilgrims on their hat or the rape of their coat, as a
mark of their having crossed the sea for the purpose of paying their devotions at the holy shrine
in Palestine; in commemoration of which they are still preserved in the armorial bearings of many
families of distinction whose ancestors had performed that ceremony. From its use by cooks
now, this shell has given the name to ' scalloiwd' Oysters. In early times, when plates and drink-
ing-vessels were not so plentiful as they are now, the concave or hollow valve of the Scallop served
as a cup, and the flat valve for a plate. The idea has even been carried out by our pottery man
ufat 'hirers, and plates and dishes have been molded after the forms of bivalve shells. Reticules,
needle-books, pincushions, and other articles are made by shell-dealers with the scallop shell."

Of both the Scallop and the Mussel a special account will be given in another place, con-
sidering the value of each commercially.

The fresh-water bivalves belonging to the large family of the Unionidas ought not to be
omitted in this review. To the raccoon, otter, muskr.it, and many other mammals and birds, as well
as to the fishes, they are a steady source of food. Observing this, the Indians adopted them from
the earliest prehistoric times as edible, and enormous heaps of shells upon the banks of many



710 NATURAL HISTORY OF AQUATIC ANIMALS.

of our interior rivers, especially in Pennsylvania, the Ohio Valley, and the Southern States, show
how extensively and constantly they were sought. White men occasionally eat them, and in case
of extreme hunger would perhaps pronounce a roasted Unio or Anodonta good. Some years ago a
great furore was created by the discovery of a fine pearl in one of the Uiiios of North Carolina a
thing likely to happen in the case of any of them, since they have an interior which is often as finely
nacreous as that of the Mother-of-pearl Oyster of the Gulf of California. Hundreds of persons
immediately began searching the rivers all over that region, and total extirpation of the poor Mus-
sels was prevented only by the discouragement of finding few pearls and these of insignificant
size. It is probable that from the heavier species, in captivity, good pearls might be obtained
artificially by following the plan pursued by the Chinese with their sea Pearl-oyster. The experi-
ment is worth trying.

Shells of fresh-water Mussels are frequently worked up into pocket-books and other fancy arti-
cles, as in the case of the Mytilus. When the brown epidermis is removed a beautiful iridescent
polish is obtainable. There are almost innumerable varieties of these fresh-water Mussels, and
full cabinets have a considerable value.

The manufacture of jewelry and shell-flowers consumes large quantities of small shells and
and the polished opercula of large ones, chiefly derived from Florida. It is said that in London
about a million of the commoner sorts are sold to street-sellers and country peddlers, who retail
them to be made into fancy work and as objects of curiosity. The same thing is frequently seen
in the United States, though more commonly in the shape of the traveling dealer who brings
a large and varied stock to a country town, hires a shop for several weeks, and sells his shells
mainly by auction.

The spread of commerce and improved facilities for dredging have made species once rare now
common ; but astonishing prices, reaching hundreds of dollars for a single specimen, in some cases
were paid by owners of conchological cabinets for rare species half a century ago. This stimulated
research and distributed much money among sea-side collectors. Even now dealers in objects of
of natural history derive a large profit by importing shells whose only value is their scientific
importance ; while the institutions devoted to their study and the books to which an interest in
conchology have given rise are entitled to a money estimation not to be despised.




X. A CONTRIBUTION TO THE LIFE-HISTORY OF THE OYSTER.
(Ostrea virginica, Graelin, and 0. edulis, Linn.)

By JOHN A. RYDER.
210. OUTLINE SKETCH OF THE COARSER ANATOMY OF THE OYSTER.

" The general structure of an Oyster may be roughly represented by a long, narrow memorandum
book, with the back at one of the narrow ends instead of at one of the long ones. The covers of
such a book represent the two shells of the Oyster, and the back represents the hinge, or the
area where the two valves of the shell are fastened together by the hinge ligament. This ligament
is an elastic, dark-brown structure, which is placed in such a relation to the valves of the shell
that it tends to throw their free ends a little apart. In order to understand its manner of working,
opeu the memorandum book and place between its leaves, close to the back, a small piece of
rubber to represent the ligament. If the free ends of the cover are pulled together the rubber
will be compressed and will throw the covers apart as soon as they are loosened. The ligament
of the oyster-shell tends, by its elasticity, to keep the shell o]>en at all times, and while the
Oyster is lying undisturbed upon the bottom, or when its muscle is cut, or when the animal is
dying or dead, the edges of the shell are separated a little.

"The shell is lined by a thin membrane, the mantle, which folds down on each side, and may
be compared to the leaf next the cover ou each side of the book. The next two leaves of each
side roughly represent the four gills, the so-called 'beard' of the Oyster, which hang down like
leaves into the space inside the two lobes of the mantle. The remaining leaves may be compared
to the body or visceral mans of the Oyster.

"Although the Oyster lies upon the bottom, with one shell above and one below, the shells
are not upon the top and bottom of the body, but upon the right and left sides. The two shells
are symmetrical in the young Oyster, but after it becomes attached the lower or attached side
grows faster than the other, and becomes deep and spoon-shaped, while the free valve remains
nearly flat. In nearly every case the lower or deep valve is the left. As the hinge marks the
anterior end of the body, an Oyster which is held on edge, with the hinge away from the observer
and the flat valve on the right side, will be placed with its dorsal surface uppermost, its ventral
surface below, its anterior end away from' the observer, and its posterior end toward him, and its
right and left sides on his right and left hands, respectively.

" In order to examine the soft parts, the Oyster should be opened by gently working a thin, flat
knife-blade under the posterior end of the right valve of the shell, and pushing the blade forward
until it strikes and cuts the strong adductor muscle, which passes from one shell to another and
pulls them together. As soon as this muscle is cut the valves separate a little, and the right
valve may be raised up and broken off from the left, thus exposing the right side of the body.
The surface of the body is covered by the mantle, a thin membrane which is attached to the body
over a great part of its surface, but hangs free like a curtain around nearly the whole circum-
ference. By raising its edge, or gently tearing the whole right half away from the body, the gills

711



712 NATURAL HISTORY OF AQUATIC ANIMALS.

will be exposed. These are four parallel plates which occupy the ventral half of the mantle cavity
and extend from the posterior nearly to the anterior end of the body. Their ventral edges are
free, but their dorsal edges are united to each other, to the mantle, and to the body. The space
above, or dorsal to the posterior ends of the gills, is occupied by ihe oval, firm adductor muscle,
the so-called 'heart.' For some time I was at a loss to know how the muscle came to be called
the 'heart,' but a friend told me that he had always supposed that this was the heart, since the
Oyster dies when it is injured. The supposed 'death' is simply the opening of the shell when the
animal loses the power to keep it shut, Between this muscle and the hinge the space above the
gills is occupied by the body, or visceral mass, which is made up mainly of the light-colored repro-
ductive organs and the dark-colored digestive organs, packed together in one continuous mass.

" If the Oyster has been opened very carefully, a transparent, crescent-shaped space will be
seen between the muscle and the visceral mass. This space is the pericardium, and if the delicate
membrane which forms its sides be carefully cut away, the heart may be found without any
difficulty, lying in this cavity, and pulsating slowly. If the Oyster has been opened roughly, or
if it has been out of water for some time, the rate of beating may be as low as one a minute,
or even less, so the heart must be watched attentively for some time in order to see one of
the contractions." 1

The dark-purple scars near the centers of both valves are simply the areas covered by the
attachments of the adductor, which is composed of a vast number of extremely fine muscular
fibers, which collectively pass straight across the space between the inside of the valves, being
firmly fixed at either end of the latter. The tendency to separate the valves at their free borders,
inherent in the 1 igament, is balanced or counteracted by the muscle. The head end of the animal
lies close against the hinge, the point where, as previously described, the two valves are firmly
fixed to each other by a dark-brown, crescent-shaped body, the ligament, which, while it serves to
attach, also tends, by reason of its elastic properties, to cause the valves to separate at their free
borders in order to allow the passage of the water inward to the gills, and of food to the mouth,
while it also allows the water which has passed through the gills to escape by way of the cavity
above the gills which is prolonged into the cloaca, carrying along with it, in its outward passage,
the faeces from the vent. The foregoing lines fairly describe the mechanism of the shell and in
part the physiological significance of the same.

The structure of the shell is laminar, or, in other words, it is composed of numerous layers of
a material identical in composition with chalk, deposited one on the other by the mantle, the organ
which builds the whole shell in this way, the chalky substance being derived from the fluids of the
animal, which in turn derives it from its food. These layers, deposited as they are internally, in
a horny organic matrix, as growth proceeds project in succession pa st each other at the free edges
of the valves and external surface of the shell, so that the successive deposits may readily be
distinguished on its external surface, giving rise to a very rough imbricated appearance of the
edges of the layers on the outside. Attempts which I have made to determine the age of Oysters
from a supposed periodic deposition of the shelly material, corresponding to the years of its age, I
find to be impracticable.

The structure in the layers of the shell of the chalk or calcic carbonate is minutely prismatic (
Nathusius-Konig.sborii lias found that certain portions of the shell of the European Oyster contain
very minute air-spaces. Both native and foreign species are found to have hollow cavities in the
valves, usually containing water.

1 W. K. BROOKS : Development of the American Oyster. Studies from the Biological Laboratory of Johns Hopkins
University, No. IV, 1880, pp. 5-7.



TBE ANATOMY OF THE OYSTER, 713

In front of the gills, that is, between i linn and the hinge, there ore four fleahy Haps the
li|i- two on each side of the body. They are much like the gills in appearance, and they are
connected with each other l>y two ridges which run across the middle of the body clow* to the
anterior end, and between these folds is the large oval mouth, which is thus seen to In- situated,
not at the open end of the shell, but as far away from it as possible. As the Oyster is immovably
fixed upon the bottom, and has no arms or other structures for seizing food and carrying it to the
mouth, the question how it obtains its food at once suggests itself. If a fragment of one of the gills
is examined with a microscope it will be found to be covered with very small hairs, or cilia,
arranged in rows. Each of these cilia is constantly swinging back and forth, with a motion
something like that of an oar in rowing. The motion is quick and strong in one direction and
slower in the other. As all the cilia of a row swing together, they act like a line of oars, only they
are fastened to the gill, and as this is immovable, they do not move forward through the water, but
produce a current of water in the opposite direction. This action is not directed by the animal,



Online LibraryG. Brown (George Brown) GoodeThe fisheries and fishery industries of the United States (Volume 1:1) → online text (page 118 of 146)