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THE DECENNIAL PUBLICATIONS OF
THE UNIVERSITY OF CHICAGO

THE DECENNIAL PUBLICATIONS

ISSUED IN COMMEMORATION OF THE COMPLETION OF THE FIRST TEN
TEARS OF THE UNIVERSITY'S EXISTENCE

AUTHORIZED BY THE BOARD OF TRUSTEES ON THE RECOMMENDATION
OF THE PRESIDENT AND SENATE

EDITED BY A COMMITTEE APPOINTED BY THE SENATE

EDWARD CAPPS
STARR WILLARD CUTTING ROLLIN D. SALISBURY

JAMES ROWLAND ANGELL WILLIAM I. THOMAS SHAILER MATHEWS

CAKL DARLING BUCK FREDERIC IVES CARPENTER OSKAR BOLZA

JULIUS STIEGLITZ JACQUES LOEB

4

iC>.««^'"'<»

THESE VOLUMES ARE DEDICATED

TO THE MEN AND WOMEN

OF OUB TIME AND COUNTRY WHO BY WISE AND GENEROUS GIVING

HAVE ENCOURAGED THE SEARCH AFTER TRUTH

IN ALL DEPARTMENTS OF KNOWLEDGE

INVESTIGATIONS

THE UNIVERSITY OF CHICAGO

FOUNDED BT JOHN D. BOCKEFELLEE

INVESTIGATIONS REPEESENTING
THE DEPARTMENTS

ZOOLOGY ANATOMY PHYSIOLOGY NEUROLOGY
BOTANY PATHOLOGY BACTERIOLOGY

THE DECENNIAL PUBLICATIONS
FIRST SERIES VOLUME X

CHICAGO

THE UNIVERSITY OF CHICAGO PRESS

1903

Copyright 1903
BY THE UNIVERSITY OF CHICAGO

\v K- \

CONTENTS

I. On the Production and Suppression of Muscular Twitchings and

Hypersensitiveness op the Skin by Electrolytes - - - 1

By Jacques Loeb, Professor and Head of the Department of Physi-
ology

II. On a Formula for Determining the Weight of the Central Ner-
vous System of the Frog from the Weight and Length op
its Entire Body ___ 15

By Henry H. Donaldson, Professor and Head of the Department of
Neurology

III. The Development of the Colors and Color Patterns of Coleop-

TERA, WITH Observations upon the Development of Color in
Other Orders of Insects (with Plates I-III) - - . 31

By William Lawrence Tower, Assistant in Embryology

IV. The Artificial Production of Spores in Monas by a Keduction

OF the Temperature - - - -- - --71

By Arthur W. Greeley, Assistant in Physiology

V. The Self-Purification of Streams ------ 79

By Edwin Cakes Jordan, Associate Professor of Bacteriology

VI. The Lecithans : Their Function in the Life of the Cell - 91

By Waldemar Koch, Assistant in Pharmacology

VII. A Contribution to the Physical Analysis of the Phenomena of

Absorption of Liquids by Animal Tissues _ - _ _ 103
By Ralph Waldo Webster, Assistant in Physiological Chemistry

VIII. The Distribution of Blood-Vessels in the Labyrinth of the Ear

of Sus Scrofa Domesticus (with Plates V-XII) _ _ - 135

By George E. Shambaugh, Instructor in Anatomy of the Ear, Nose,
and Throat

ix

127055

X Contents

IX. The Animal Ecology op the Cold Spring Sand Spit, with Remabks

ON THE ThEOEY OP ADAPTATION - - - - - -155

By Chables Benedict Davenport, Associate Professor of Zoology and
Embryology

X. The Fineb Structube op the Neurones in the Nervous System

OF the White Rat (with Plates XIII, XIV) - - - - 177
By Shinkishi Hatai, Research Assistant in Neurology

XI. The Phylogeny of Angiosperms - - 191

By John Merle Coulter, Professor and Head of the Department of
Botany

XII. Studies in Fat Necrosis - - - - -'- - - 197
By H. Gideon Wells, Instructor in Pathology

XIII. Oogenesis in Sapbolegnia (with Plates XV, XVI) . _ . 225

By Bradley Moore Davis, Assistant Professor of Botany [Hull
Botanical Laboratory]

XIV. The Eably Development of Lepidosteus Osseus (with Plates

XVII, XVIII) ---------- 259

By Albert Chauncey Eycleshymer, Assistant Professor of Anatomy

XV. The Stbuctube of the Glands of Bbunneb (with Plates XIX-

XXIV) - 277

By Robert Russell Bensley, Assistant Professor of Anatomy

XVI. Mitosis in Pellia (with Plates XXV-XXVII) - - . - 327

By Charles Joseph Chamberlain, Instructor in Morphology and
Cytology

XVII. A Descbiption op the Bbains and Spinal Cobd op Two Bbothebs
Dead of Hebeditaby Ataxia. (Cases XVIII and XX of the
Sebies in the Family Descbibed by Db. Sangeb Bbown); (with
plates XXVIII-XXXIX) - - 347

By Lewellys Franklin Barker, Professor and Head of the Depart-
ment of Anatomy. With an Introduction by Dr. Sanger Brown

THE ANIMAL ECOLOGY OF THE COLD SPRING

SAND SPIT

THE ANIMAL ECOLOGY OF THE COLD SPRING SAND
SPIT, WITH REMARKS ON THE THEORY OF ADAP-
TATION

C. B. Davenpobt

Cold Spring sand spit runs from the west shore of Cold Spring Harbor, Long
Island, eastward to within 100 or 200 feet of the eastern shore of the harbor. The
history of the formation of the spit is briefly this : Cold Spring Harbor (Fig. 1) is a
fiord-like re-entrant about ten kilome-
ters long, emptying at its lower or
northern end into Long Island Sound
about one-fifth of the way from Hell
Gate at New York city to "The Eace,"
south of New London. The Sound
itself, 175 kilometers long by 35 kilo-
meters broad at its widest point, and
having a prevailing depth of about 30
meters, receives large streams of water
from the north — the Connecticut,
Housatonic, and Quinnipiac rivers,
and many minor ones. These give
it a low specific gravity, 1.020, and
a muddy bottom. Long Island is
covered over its northern part with
glacial debris, forming hills that rise
to a height of over 100 meters. Be-
tween these hills streams flowing
north have cut valleys and, in the
general sinking to which the whole
area has been subjected, these valleys have become drowned, forming long, straight
but shallow harbors of which Cold Spring Harbor is an excellent type (Shaler, 1902).
Into the head of the harbor a small stream flows with a summer discharge of not far from
five cubic meters per minute. This stream is dammed thrice along its course of two
miles, so that the deposit that it carries into the basin above the beach is only fine mud.

The effective winds at Cold Spring Harbor blow from the northeast and, striking
with violence upon the bluffs on the west side of the harbor, tend to wear them away.
The currents setting southward then carry this eroded material until it is dropped in
the shallow and protected waters of the upper end of the harbor, where the sand spit or
" beach" is now found. The inner harbor thus cut off is about 800 meters long by 600

157

40' 53

. 40 52

Fig. 1.-
Beach).

-Map of Cold Spring Harbor, showing spit (Cold Spring

4 The Animal Ecology of the Cold Spring Sand Spit

wide, and at mean high tide has a prevailing depth of less than 2.5 meters. Its sandy
bottom is for the most part covered with half a meter of fine black mud. This is
largely exposed at low tide, and supports an abundant growth of "sea cabbage"
(Ulva). The specific gravity of the water at high tide varies from 1.018 near the
entrance to the inner harbor to 1.005 at the surface near the inlet of the creek. Near
the "gut" where the tides rush in and out of the inner harbor the bottom is kept
scoured and consists of gravel and stones. Outside the sand spit the water has a pre-

FiG. 2. — View of Cold Spring Harbor at high tide looking north. The inner harbor is in the foreground ; between
it and the outer harbor is seen the sand spit. Close to the sand spit on the inside is a fringe of Spartina polystachya.

vailing specific gravity of 1.019 and is about 6 to 8 meters deep at high water. A
bar (Fig. 2), almost submerged at high tide and consisting largely of hard mud, has
formed opposite to the outer entrance to the gut and afPords a "shallow sea" fauna.

The sand spit itself (Figs. 2 and 3) is 600 meters long and varies in width from
80 meters at its western end to 15 meters at its eastern end at high water. The
prevailing width is about 40 meters. The highest part of the spit is about one meter
above mean high tide, and the average height of tide is 2.4 meters. The slope is
gradual on the outside (north side), it being 40 meters from high to low water at
the western third of the spit. The slope increases to 2.4 meters in 15 at the eastern
end. The material of which the spit is built is sand, which at the western end
contains much gravel, apparently because of the greater carrying power of the surf,
which is highest here. At the gut the sand is very coarse on account of the rush-
ing tide. In the middle stretches of the beach the sand is finer. On the inner face
of the spit mud is deposited. On account of the sandy beach and the currents and
surf that are washing it all the time, no plants grow on the outside of the sand spit

158

C. B. Davenport

between average tides. On the inside of the spit, on the other hand, the marsh grass,
Spartina, finds abundant foothold. All these facts have an important influence on
the distribution of the animals of the sand spit. Indeed, for the purposes of this
account of the fauna of the spit it will be necessary to treat separately its outer and
inner margins and its tip, just because the conditions are so different in the three
situations.

Fig. 3. — View of sand spit taken uear western end luukiu^' east. Terrestrial bt)rder zone with Ammophyla in the
foreground. The outer beach with the storm bluff, wreckage-strewn upper beach, and lower beach. At the right the
inner beach, passing into mud fiats at the edge of which Spartina polystachya is growing.

A. ANIMALS OF THE OUTER BEACH

The outer beach may, for our purposes, be divided into three zones which we
may herein designate as : (1) the submerged zone ; (2) the lower beach ; and (3) the
upper beach. The submerged zone includes all that portion of the beach that lies
below mean low tide, but which may be exposed by the lowest spring tides combined
with southerly winds (Fig. 4). It is a region that is normally covered with water ; it is
the very margin of the shallow sea. The lower beach is that zone which lies between
mean low tide and mean high tide. It is the zone that is twice each day exposed to
the air and submerged. It passes without any sharp break into the submerged zone
(Figs. 4 and 5). The upper beach is limited on the one hand by the line of debris that
marks the average high tide, and on the other by a bluff, half a meter high, that has
been cut by storms (Fig. 5).

159

6 The Animal Ecology of the Cold Spbing Sand Spit

i. fauna of the submebged zone

The animals that live below the high-tide line may be considered under four
heads : (a) sessile species, (6) crawling species, (c) burrowing species, and (d) swim-
ming species.

a. The sessile species of animals, inhabiting the lower beach, include certain
molluscs, especially bivalves, or Lamellibranchiata. All the lamellibranchs feed on
minute particles of organic matter : Algae, Infusoria, and decaying bits of organisms.

Fig. 4. — Photograph of lower beach, north side of sand spit, near the eastern end, at very low tide. The gut is
seen in the background. At the water's edge (submerged zone) is a dense growth of the alga Enteromorpha. The naked
lower beach is thickly peopled with the mud snail, Nassa obsoleta, visible as dots in the photograph.

The silt brought down by the creek is rich in such material and the algae thrive on
the mud flats, consequently these flats and the shallow sea around the flats are espe-
cially favorable feeding-grounds for these molluscs. Here occur oysters (Ostrea vir-
giniana) in a semi-domesticated state. They normally attach themselves to some solid
object while still young, but those of Cold Spring Harbor have been mostly trans-
planted and lie loose in the shallow waters, but altogether incapable of movement or
of any other defense than that provided by their two thick valves. Here also occurs
the scallop (Pecten irradians), which attaches itself while yet less than two weeks old,
in the middle of August. The attachment is chiefly to eel-grass or to small stones.
About the middle of September the scallops migrate into the inner harbor to live on

160

C. B. Davenport

the mud-flats like the oyster, but they never lose their power of free migration. The
jingle shells (Anomia simplex) are permanently attached to stones or larger shells,
such as Pecten, from early life. On the lower beach one also finds two species of
Area (Area transversa and Area pexata) ; the hen-clams, Mactra solidissima and Mac-
tra lateralis; the hard clam, Venus mercenaria ; and Liocardium mortoni — all lying
on or imbedded in the muddy bottom. Here also are found certain species of lamel-
libranchs that burrow in the mud or sand and, to facilitate that burrowing, have
become elongated; namely, the soft-shelled clam, Mya arenaria; the razor clam,
Ensis americana, and Solenomya velum. This great group of bivalves represents then
a society of animals that are fairly common because of favorable food conditions, but
very helpless and much exposed to predaceous animals, were it not for their hard shell
or their habit of burrowing into the mud.

b. The crawling species belong chiefly to the three groups of MoUusca, Echino-
derma, and Crustacea. The crawling molluscs are slow-moving snails (Gastropoda)
which are there partly to feed on decaying animal and vegetable matter, partly to feed
on the growing Ulva, and partly to prey upon such living animals, chiefly bivalves, as
have no means of escape. The chief omnivorous and carrion snail is the mud snail,
Nassa obsoleta (Fig 4), which is abundant everywhere and even remains exposed on
the middle beach at low tide, if busy feeding on a dead oyster. The little snails,
Anachis avara and Astyris lunata, feed on the Ulva, or sea lettuce. The carnivorous
species are of larger size and include two MuricidsG, Eupleura caudata and Urosalpinx
cinerea ("oyster-drill"), and the great whelks, Fulgur caniculatum and Fulgur carica.
All these feed upon oysters, scallops, and other surface bivalves by drilling holes
through the shell. Two species of Naticidse, Neverita duplicata and Lunatia heros,
seek out the burrowing lamellibranchs, and so we find them burrowing into the sand.
Then, too, they find in the sand of the beach the proper material for their egg cases,
which are made out of agglutinated sand molded in the shape of a spiral collar. The
crawling echinoderms are chiefly the starflshes, which are here because of the oysters
and other bivalves upon which they prey. They cannot bore through the oyster's
shell, and so they smother it until it is forced to open its valves for fresh water. The
crawling Crustacea, finally, feed on organic debris of all sorts. Here belong the crabs,
such as the three spider crabs, Libinia canaliculata, Libinia emarginata, and Libinia
dubia, of which the latter comes farthest in-shore. Here, too, are the three mud crabs,
Panopeus depresus, Panopeus herbstii, and Panopeus sayi, of which three the latter
is found nearest the sand spit. On the very edge of the submerged zone are found
also the two hermit crabs; the small one, Eupagurus longicarpus, finds protection for
its abdomen in the cast-off shells of the small gastropods Nassa and Anachis. The
large species, Eupagurus pollicaris, occupies such large shells as those of Lunatia heros
and Fulgur carica. These scavengers, carrying their borrowed shells behind them,
travel quickly along, but just below, the edge of the water, seeking for dead fish and
other organic matter that may be resting there. Finally, the horseshoe crab, Limulus

161

8 The Animal Ecology of the Cold Spring Sand Spit

polyphemus, the largest and most aberrant of our Crustacea, will be seen, especially
during June, traveling over the shallow water and occasionally coming to land to lay
its eggs in the sand.

c. The burrowing animals of the submerged zone constitute a remarkable fauna
of, for the most part, elongated animals. We have already seen that many molluscs
burrow. So do a few sea anemones, such as the white-armed sea anemone, Sagartia
leucolena, and the flesh -colored or white Halocampa producta. These sea anemones
seem to feed on bits of organic remains, of which the sand is full. The other burrow-
ers are here for a similar purpose; the circumpo^: sea cucumber, Synapta inhserens;
the worm that shows affinities with vertebrates, B^^^glossus Kowalevskii ; two nem-
ertines, Cerebratulus leidyi and Cerebratulus lacteuS^ and some seventeen different
kinds of jointed worms, Annelida. All these find shelter, moisture, and food in the
sand and mud beneath the sea bottom. But their immunity from attack is not com-
plete, for as the moles have followed the earthworms and insect larvae into the sub-
aerial ground, so have several predaceous Crustacea followed the annelids into the
mud. These are: the mantis shrimp, Squilla empusa, which is only a little smaller
than the lobster, and Callianassa stimpsoni and Gebia affinis, that are somewhat smaller
than a large crayfish.

d. The swimming animals are partly scavengers and partly predaceous. To the
first class belong the prawn Palsemonetes vulgaris, which scours the edge of the tide
for floating debris; and also the swimming crabs, the blue crab, Callinectes hastatus,
and the commoner "lady crab," Platyonichus ocellatus. Here, too, we may place the
little killifishes, Fundulus, although these pick up many live shore snails. The majority
of the fishes are predaceous, feeding on the crawling and even the burrowing
species that I have enumerated. The "skates" that lie close to the bottom catch
burrowing worms and molluscs and also the snail Lunatia heros. The sand sharks
and dogfish (Carcharias littoralis and Mustelus canis) gather in the spider crabs, squil-
las, and hermit crabs. The flounders, likewise, living close to the bottom, get Gebia
and the prawns. The toad-fish, which lays its eggs in old shoes or in tin cans or
under stones, feeds on the mud snail, Nassa, on crabs, and on prawns. Thus we see
that in the shallow sea each species that occurs is present on account of particular
relations that it bears to other species or to the non-living environment. The pres-
ence of the sharks is determined by that of the squillas, the squillas by the worms, the
worms by the decaying vegetation, this by the living vegetation, and this by the salts
and the nitrogenous food brought down by the creek from the valley above. This
microcosm of the submerged zone affects in turn the lower and the upper beaches.

II. THE fauna of the LOWER BEACH

As already stated, the lower beach is a zone where aquatic and terrestrial con-
ditions alternate every day. On this account, and on account of the sand, it is an area
devoid of all living vegetation excepting the unicellular algae that grow upon the

162

C. B. Davenpobt 9

stones (Fig. 4). It is also a region where oxygenation is combined with abundant
moisture, so that conditions peculiarly favorable for respiration would seem to be
afforded.

A fine layer of silt is dropped over the whole surface with each flood tide, afford-
ing thus abundant but microscopic food. But, on the other hand, it is a region of
great exposure to terrestrial animals ; so that only the stratum a little below the surface
offers great safety. Also the lower beach is a region of wave action which makes it
difiicult for animals to secure a permanent place on it. Finally, and most important
of all, the waves and currents cause^^ sands to shift, and this adds to the difficulty
of maintaining a foothold. Cona^Hently there are but few animals living on the
lower beach, and such as there. ^^Wive a curious and very strenuous life.

All over the lower beach will be found, upon careful examination, large num-
bers of extremely minute and active insects belonging to the group of Thysanura.
These are arctic forms of CoUembola of the species Xenylla humicola, O. Fabr. and
Isotoma besselsii. Pack., together with an occasional Anurida maritima, Guer.* These
CoUembola are feeding on the rich microscopic debris which has been dropped on the
lower beach. Being insects, they are air breathers; and the question arises: What
do they do when the tide comes in? To answer this question I made measurements
of the area occupied by the CoUembola at different stages of tide. At tides lower than
one-half tide the upper limit of the Collombolan zone is about nineteen meters north
of the storm -cut bluff, or about ten meters north (i. e., seaward) of the mean high-tide
line. The lower limit is about two meters from the momentary tide-line. As the
tide retreats the lower limit follows, while the upper limit remains constant. Thus,
on September 10, 1901, with falling tide, the following determinations were made:

Distance fboh Storm Bluff

HOUB

Upper Limit of
CoUembola .

Lower Limit of
CoUembola

3:10 p. M

17.7 m.
17.7 m.
17.7 m.

28.4 m.

3:30 p. M

29.5 m.

4:50 p. M. (low-tide)

31.1 m.

Note that the lower limit of the CoUembola travels down pari passu with the
tide.

As the tide rises, the CoUembola tend to retreat before the edge of the water, so
that they are even crowded together there. Thus, on September 10, at 7 A. M. (one-
third tide, rising), the lower edge of the Collembolan zone was about three meters
away from the water's edge. As the tide rises still higher they crawl into the sand,
until, at high tide, most of the CoUembola are under the sea. But not all of the Col-
lembola are there. At high tide one finds some of them floating on the quiet water out

1 For the determination of these species I am indebted to my friend, Dr. J. W. Folsom, of the University of Illinois.
(Cf. Wahlgren, 1899; Folsom, 1901.)

163

10 The Animal Ecology of the Cold Spring Sand Spit

at a distance of ten meters or more, and moving hither and thither upon the surface.
We conclude then that the rising tide has caught up with certain of the little insects.
They rest upon the surface of the water by virtue of numberless fine hairs with which
they are covered, in which the air is entangled so that the bodies of the insects are
prevented from getting wet These are chiefly Anurida.

A second species that occurs on the middle beach in great numbers during the
latter part of June is the horseshoe crab, Limulus polyphemus. This occurs here
because it lays its eggs in the sand of the beach, thereby reaping the advantage of the
superior oxygenation afforded by this situation over sand constantly submerged. The
eggs are laid in nests containing several hundred each. The eggs are oval and about
two millimeters in diameter. Each is enveloped in a tough membrane so that the sand
cannot injure it. The position of the nest may be detected by a slight depression in
the surface over it, and by the absence of pebbles. Not all the middle beach is
occupied by these nests, but only those regions where the sand is coarse enough to let
water through readily, but not so gravelly as to make hard digging. The east end of
the sand spit where the current flows swiftest affords the best conditions, and here the
nests are crowded together. In June also one finds many carcasses of female horse-
shoe crabs that have died in consequence of oviposition ; for, as in many other species,
oviposition is accompanied by a great mortality. Most of these carcasses are even-
tually thrown up to the high-tide line, and their fate will be considered in connection
with the fauna of the upper beach.

Finally, mention should be made of the great annelid. Nereis limbata, that
occurs burrowing in the sand above low-water mark. This again is confined to the tip
of the sand spit where oxygenation is best carried on.

III. THE FAUNA OF THE UPPER BEACH

The upper beach I shall define as the zone including the high-tide line and above
to the storm bluff (Fig. 3 left, Fig. 5). This region is inhabited by a very few annual
plants; its main characteristic, however, is the debris cast up by the sea (Fig. 5). All over
the world the upper beach is the graveyard of the shallow sea. In this graveyard two
sorts of remains are found: first, such as have been floating on the surface of the sea;
and, second, such as have fallen to or were lying on the bottom of the shallow sea.
The floating remains are carried in toward the shore by winds from the sea. If
the sea is quiet, they are merely dropped at the time the tide begins to fall ; conse-
quently they mark the high-water line (Fig. 5). If the sea is heavy, the floating or
drowned debris may be thrown against the upper part of the upper beach and even
against the storm bluff. This flotsam and jetsam consists, in the first place, of such
things as lumber and articles of wood and cork ; fruits and seeds ; bits of eel grass ;
stems of last year's marsh grass, Spartina; fronds of Ulva torn from the mud flats;
jelly fishes; drowned insects, especially heavy -bodied beetles, which have probably
been blown out to sea and been drowned or have fallen in during migration. The

164

C. B. Davenpoet

11

second class includes chiefly empty shells, whose inhabitants have perhaps met with a
violent death through predaceous animals, or the smothering of a stirred up muddy
bottom,^ also the dead bodies of Crustacea, such as Limulus. This debris is piled up
at the lower edge of the middle beach and is renewed twice a day. Especially, how-
ever, after a storm is the accumulation large. At such times and at certain seasons of
the year one may meet with particular species in large numbers. Thus, early in Sep-
tember, 1901, as the young Pectens were swimming into the inner harbor, a combina-

FiG. 5. — Photograph of north side of sand spit, near the western end, at low tide. In the central foreground is the
high-tide line, marked by a mass of d6bris. On the left is the gravelly lower beach; the middle beach and storm
bluff are at the right.

tion of high tide and sea breeze left thousands of them stranded on the upper and
even on the lower beach. ^ The drowned insects are largely leaf eaters (Chrysome-
lidse, including the Colorado potato beetle) and, especially in the early summer, lady-
birds (Coccinellidae) of various species. All of these constitute a rich, frequently
replenished food supply, the only disadvantage connected with it being the dangerous
proximity of the sea, with its occasional very high tides and its storm-born breakers.
As could have been anticipated, certain animals have come together to make use of
this food material. Some are herbivorous, others are scavengers, and others still are
predaceous.

2 In March, 1890, the levee gave way on the left bank of
the Mississippi river above New Orleans. The waters
pouring through Lake Ponchartrain into western Missis-
sippi Sound so stirred up the muddy bottom that the great
beds of oysters of this region were killed. (Smith, 1894.)

3 During a visit to Santa Rosa island, outside of Pensa-
cola Bay, Florida, in March, 1902, 1 found the beach cov-
ered with thousands of Portuguese men-of-war (Physalia),
and the floating gastropod, Janthina fragilis, thrown up
by the southerly storms.

165

12 The Animal Ecology of the Cold Spring Sand Spit

Of the herbivorous feeders on the wreckage of the sea may be mentioned, first
of all, the Amphipoda, marine Crustacea which are so adapted to a terrestrial life that
they are rarely submerged. At Cold Spring Harbor two species are found — the small,
dark Orchestia agilis and the large, sand-colored Talorchestia longicornis. Both may
be seen in great numbers by turning over some of the cast-up Ulva fronds, under
which they live and upon which they feed. Here they dwell in a saturated atmos-
phere and so need no special modification of the respiratory apparatus to fit them for
breathing air. They both burrow, also, forming holes varying from three to five
millimeters in diameter in the fine sand under or slightly above the line of wreckage.
These holes enable the amphipods to reach moisture, they prevent them from being
swept away by the sea, and they may serve as nests for eggs. For some reason the
Talorchestia only is found at the tip of the spit. If it be asked why these Amphi-
pods have left the water thus to assume a half-terrestrial life, I think it is a sufficient
answer to say, first, that they find here abundant food ; second, that they are here com-
paratively immune from the attacks of their greatest enemies — the fish; and, third,
that their organization permits them readily to assume a semi-terrestrial life, as is
shown by the fact that some of their allies have become even more terrestrial than
they. (Compare Talitrus platycheles, and Talitrus saltator, Semper, 1881, p. 188.)
That the Talorchestia is no longer an aquatic animal is shown by the way it retreats
before the tide, especially if abnormally high.

Secondly, rove-beetles (Staphylinidse) of the genus Bledius are found in the
debris. This terrestrial insect is here found side by side with the marine Talorchestia,
even burrowing into the sand. It feeds upon decaying vegetable matter. A third
organism found under the debris is a minute white earthworm of world-wide distribu-
tion. This is Enchytrseus albidus Henle (Halodrilus littoralis of Verrill, 1878).

As the plant debris is being devoured by the amphipods, staphylinids, and
Enchytrseus, so the animal remains are being carried off by a number of scavengers.
Among these the ants are the most important; there are two species of them. The
first, Formica rufa var. obscuriventris Mayr, is reddish brown and about four milli-
meters long (see Emery, 1893). It digs holes in the sand in the upper part of the
upper beach, the grains of sand being brought individually to the surface and
deposited in a ring around the hole. This ant also occurs under the shelter of boards
and logs. Immediately after the tide has begun to fall and dropped its burden of car-
casses these ants sally forth in paths that run perpendicularly to the high-tide line and
begin to seize and carry to their nests the drowned insects that have been left there
stranded. A second species of ant has its home somewhat farther out of reach of the
tide; but its habits are quite similar.

There is, however, a larger carrion fauna to be utilized. I have already referred
to the dead horseshoe crabs and the dead molluscs that are left on the shore. These
soon attract great numbers of the flesh flies (Sarcophaga carnaria) which lay their
eggs in the carrion. A second fly with bronze abdomen (undetermined) is also found

166

C. B. Davenport 13

here. To test the quickness with which these flies accumulate I took a recently
drowned turtle from the water at 3 p. m. July 7, and left it at the edge of the retreat-
ing tide. At 4:15 p. m. (wind south) I counted over thirty of the bronze flies upon
it. It remains to be determined whether it is chiefly sight or smell that attracts them.

Underneath the carcasses of the horseshoe crabs one will find also large numbers
of the carrion beetle, Necrophorus, and larvae of the museum pests (Dermestidse).

The rich fauna of carrion feeders and herbivorous and omnivorous species deter-
mines still another fauna, namely, a predaceous one. Thus, running spiders, almost
as white as the sand, frequent the upper beach and sometimes pass down to the upper
part of the lower beach. These belong to the species Lycosa cinerea — a species that
occurs commonly in Europe also, and is by no means confined to the sand of beaches.
I have seen them carrying off Orchestia toward the storm bluff. More powerful still
are the robber flies (Asilidse) which pounce upon carrion flies. Their path of flight is
curved, and at the moment of alighting an offset is taken several centimeters to one
side. Altogether the irregular flight seems well adapted to the end of putting the vic-
tim off its guard, like the curve in the path of the ball thrown by an expert baseball
player. Tiger beetles also occur abundantly on the beach in the bright sunlight,
especially in August and September. They are chiefly of the species Cicindela repanda
Dej. They are the most rapid fliers among beetles and feed upon the other insects of
the beach. Finally, all these insects must fall victim to the swift and powerful swal-
lows which course up and down the beach, especially in the latter part of the afternoon.

On the upper part of the upper beach there occur also a few stragglers from the
vegetation-grown top of the sand spit. Here one finds grasshoppers almost as white
as the sand. The white color of this species seems partly determined by the color of
the background, for placed in a cage on grass these spiders become darker, as experi-
ments at the Biological Laboratory have repeatedly shown. Whether the grasshop-
pers feed upon the dead vegetation of the tide-line was not ascertained. Crickets,
Gryllus abbreviatus, quite as black as those living in the grass, occur scatteringly on the
upper beach; and under the waste lumber the sow-bug, Oniscus, which is only half
adjusted to a terrestrial existence, finds a living on the water-soaked wood.

B. THE BEACH ON THE TIP OF THE SAND SPIT

The tip of the spit is transitional between the inner and the outer sides. Here
the sandy beaches of the north side gradually pass over into the mud-flats of the south
side with their thick growth of marsh grass, Spartina. Indeed, at the tip of the spit
there is a constant struggle going on between the upbuilding tendencies of the Spar-
tina, which tends not only to hold the mud in which it grows together, but also to
accumulate additional silt, and the scouring away tendencies of the tide that rushes
through the gut-. Wherever a weak spot appears in the mass of Spartina there a chan-
nel becomes gradually worn through (Fig. G). These channels gradually widen and
may anastomose, and thus the Spartina be left on elevated hummocks, which would

167

14

The Animal Ecology of the Cold Spring Sand Spit

seem destined to become smaller and smaller until entirely washed away. But from
this fate they are preserved by an interesting association. The current that rushes
through the channels carries with it an abundant supply of microscopic food, such
as lamellibranchs can make use of. This food is taken advantage of by the mussels which
come to line the muddy banks on the channels, and form so close a wall that erosion
is almost completely stopped (Fig. 6). Thus the mussels assist the Spartina in their
constructive work. The mussels that line the banks are Modiola plicatula, Modiola

Fig. 6.— Photograph taken at the inside of the hook of the sand spit,
looking north, at low tide, through one of the passages scoured out by the tidal
currents. At the base of the Spartina patches, on the right, are seen some of the
beds of mussels which protect the roots from exposure.

modiolus, and Mytilus edulis, the first-named being the most abundant. The channels
have irregular bottoms in which shallow pools of water stand when the tide is out.
Here the mud snails, Nassa obsoleta, aggregate, scarcely submerged. High up on the
stems of the Spartinas, exposed to the air during perhaps half the day, are found cling-
ing the Littorinas, whose lack of a siphon makes it necessary for them to keep out of
the mud. Littorina rudis and Littorina palliata were still the prevailing species in
1898 (see Balch, 1899), but in 1901 Littorina littorea, which is rapidly advancing up
the harbor, had gained a marked predominance. * The independence of the sea water
that is exhibited at the tip of the sand spit is also illustrated in the marsh at the head
of the harbor through which Cold Spring creek runs. On this marsh Littorina occurs

* This habit of clinging to rushes is even more exagger- short marsh grass twenty to thirty centimeters above the

ated in the southern Littorina irrorata. For, in a visit to water level and exposed to the sunlight. Cooke (1895, pp.

the Lagoon on Ship Island, Mississippi Sound, in March, 20, 93, 151, note) cites other cases of Littorina living out of

1902, 1 found nearly all of them living on the stems of the water.

168

C. B. Davenpobt

15

at places where it is submerged for only a short time at high tide and then under
water that is nearly fresh. Littorina rudis behaves similarly in other parts of the
world. Thus Fischer (1887, p. 182) states that at Trouville (Calvados) on the English
Channel he has found L. rudis on rocks two meters above the other marine animals
and moistened only by the highest tides. In fact, according to Simroth (1891, p. 84),

Fig. 7.— Photograph taken at half tide from the base of the sand spit, looking east, showing inner harbor,
the hook of the spit, and the gut beyond.

species of Littorina pass the winter out of water with their gill chambers full of air.
Littorina rudis, then, has evidently progressed far on the road toward adaptation to a
terrestrial life — a road that the Pulmonata must have traveled long ago.

C. THE INNER EDGE OF THE SAND SPIT

Along the whole length of the inner beach, not far from the high-tide line, occur
the holes of the fiddler crabs. These crabs belong to two species, namely, Gelasimus
pugnax and Gelasimus pugilator. A remarkable thing in the distribution of these
species is the fact that although their habitats are not markedly difiPerent their areas of
distribution are so well defined that they hardly overlap. Both species occur at the edge
of the Spartina. The pugnax is found all the way from the western, proximal end of

169

16 The Animal Ecology of the Cold Spking Sand Spit

the sand spit to about two-thirds of the way toward its eastern point. Then pugilator
abruptly comes in. For a distance of a meter or so the two species occupy ground
in common, and, so far as I could make out, peacefully. The pugnax alone occurs at
the head of the inner harbor. It burrows in the banks at a level that is reached only
by the high tides. Walking along the beach at high tide July 7, I found that many
of the fiddlers had migrated to above the high-tide level. It is clear, I think, that
they do not find submergence altogether agreeable, and it is probable that prolonged
submergence would drown them as it does Ocypoda arenaria, the sand crab of the
beaches south of Cape May. G. pugnax prefers the marshier ground and the higher
water, and it is probably that preference which determines its spacial separation from
pugilator on the sand spit.

D. THE TOP OF THE SAND SPIT (TERRESTRIAL BORDER ZONE)

Above the storm bluff on the outer beach, and at a less well-defined line on
the inner beach, lies the zone of permanent vegetation in which certain shrubs
have gained a foothold. Here the fauna at once assumes a strictly terres-
trial aspect. No close ally, even, of a marine form occurs. On the contrary,
the animals living on vegetation are precisely those species that occur in the
fields, especially the plant feeders: the plant lice (Aphidse), the leaf beetles (Chry-
somelidse), the bright-colored Buprestidse, and the various blister beetles. On the
sandy ground are sand-colored grasshoppers, sand-colored spiders, Lycosa cinerea, and
also small black spiders (Lycosa communis; cf. Emerton, 1885), black crickets, and little
red ants apparently identical with species that people the upper beach. Over the vege-
tation wandered, in early July, an abundance of the predaceous dragon-flies, a black
wasp (Polistes), and an occasional dusk-flying butterfly (HesperidsB) — quite the fauna
of a meadow not far from water.

SUMMARY ON THE ANIMAL ECOLOGY OF COLD SPRING BEACH

The outer beach is a region of breakers where debris is thrown on the shore.
The submerged zone is crowded with marine animals, some of which make their
way out of the water and others of which contribute the debris with which the upper
beach is strewn. The lower beach is covered with Collembola that feed upon micro-
scopic organic debris and crawl into the sand at high tide. The line of debris is a
rich feeding-ground for animals that live on vegetable matter and on carrion. The
debris feeders — Amphipoda, staphylinids, earthworms, ants, carrion flies, necrophorous
beetles, attract a predaceous fauna of spiders, robber flies, and tiger beetles. These
predaceous species are fed upon, in turn, by the swallows.

The tip of the beach, where the marsh grass grows, is a region of swift currents
which the lamellibranchs (mussels) find advantageous because of the food that the cur-
rents bring. The currents tend to wear away the spit, but the mussels grow so abundantly
on the banks of the channels as in turn to protect these banks from further erosion.

170

C. B. Davenpoet 17

The inside of the sand spit is a region of sedimentation. Plants grow here,
and here the plant-feeding snails and fiddlers live. The organisms that are found on
the beach are not accidentally there, nor is the fauna determined by causes remote
and too complex to be unraveled. The fauna is determined by definite proximate
causes of a simple sort that act, the world over, in the same way, and so give to a simi-
lar sea beach in other parts of the world a similar collection of animals — excepting
that each species may be replaced by another.

COMPARISON OF COLD SPRING BEACH WITH THAT OP LAKE MICHIGAN NEAR

CHICAGO

The question arises : How far is the fauna of the sea beach determined by the
beach conditions of sand, sunlight, and proximity to a body of water with its strand
zone of debris ? Will beaches in general, whether of a fresh-water lake or of the sea,
tend to have the same fauna ? To test this question I have examined the fauna of the
shore line of Lake Michigan, south of Jackson Park, Chicago. Here one finds a
sandy beach essentially like that at Cold Spring Harbor. On one side extends a huge
body of water which differs from that of the harbor chiefly in its lower specific gravity
and in the absence of marked tides, but resembles it in its waves. We may recognize
here a submerged beach and a terrestrial beach.

I. FAUNA OF THE SUBMERGED ZONE

This inundated part of the beach supports, as one would expect, a fauna the
species of which are quite unlike those of the sea. Yet we may recognize a sessile
fauna, a crawling fauna, and a swimming fauna.

a. TJie sessile fauna includes here, as in the sea, the lamellibranchs. These
belong to two families, the Unionidse and the Spheridse. These, like their marine
allies, feed on minute organic particles, chiefly algae. The Unionidse are the large
forms and seem to take the place of the marine Mactra, Venus, and Mya. They
occur in the streams and lakes of all parts of the northern hemisphere, but the group
is best developed in North America. The Spheridse are small, and take the place of
the Nuculas of Cold Spring Harbor and Donax of our southern seashore. They are
found in the streams and lakes of all countries.

h. Crawling animals belong chiefly to the groups of gastropod Mollusca and
Crustacea — the Echinoderma being wholly absent. The snails are mostly small and
seem to replace the Littorinasand the Rissoas of the seacoast. The principal crawl-
ing crustacean is the isopod Asellus communis, which lives on the wood and among
the roots of the shore line. The group is, indeed, poorly represented here as com-
pared with the sea. Burrowing animals seem to be almost entirely absent, possibly
on account of thfe absence of such predaceous forms as occur in the sea.

c. The swimming animals are here, as in the sea, partly scavengers and partly
predaceous. First of all we have in the water above the shore numerous Entomos-

171

18 The Animal Ecology of the Cold Spring Sand Spit

traca. The prawns of the sea are replaced by a very closely related species, Palss-
monetes exilipes, which may have gained the great lakes by the way of the Missis-
sippi river, in which it is abundant. The marine lobster is replaced by the crayfishes
(Cambarus propinquus and C. virilis). The predaceous forms are the fishes which
feed largely upon the snails and the Crustacea.

II. FAUNA OF THE BEACH

In the tideless lake the lower and upper beaches are hardly to be distinguished.
On the lake strand Collembola are found just as on the lower sea beach. In the line of
debris that the waves deposit are found the wrecks of all the shallow -water forms of
which I have spoken, and, in addition, the carcasses of vast numbers of insects that
have fallen into the lake, have drowned, and are cast up by the waves. This wreck-
age line affords, then, just the feeding-ground for inland species that the marine
species find on the coast. What animals do we find here? The burrowing Orches-
tidse seem, indeed, to be absent, but there is a closely related species (Allorchestes)
that lives in the shallow water. That it is not a beach burrower may be due to just
these causes that have eliminated the burrowing habit in general. But under the .
debris rove-beetles and insect larvae are to be found feeding on the vegetable matter/
And small red ants build nests on the beach and visit the debris for the carcasses of
insects. A similar carrion fly and carrion beetle (Necrophorous) occur. Feeding
upon this fauna is a running spider (Lycosa cinerea) the same as that of the coast.
Here, too, occur robber flies and tiger beetles, and even white grasshoppers. Thus
the lake beach, having a similar strand zone of decaying vegetation and plant wreck-
age with the sea, has, at a distance of nine hundred miles from the sea, excepting
certain strictly marine species, practically the same fauna as the sea. The conclusion
to be drawn from this fact is the immense importance of habitat [i. e., of environ-
mental details) in determining similarity of fauna, or, in other words, the fauna of a
point is, within limits, determined rather by the environmental conditions than by the
geographical position of the point.

REMARKS ON THE THEORY OF ADAPTATION

Everyone must admit the fact of adaptation of the structures of animals to their
environment. The generally accepted theory to account for this is that of Darwin
and Wallace that a species coming into a new habitat gradually acquires a fltness to
that habitat by the killing off of the less fit individuals born into the species. There
are some cases, as, for instance, that of the leaf insects, that of the fungus beetle,
and those of mimicry, that I can see no other explanation for but this, that an exter-
nal condition existed first and a structure or coloration was acquired by the race that
fitted or adjusted it to that external condition.

We must not, in accepting any theory as a true one, try to force it as a universal
theory and become blinded to other possible theories. Now there is another and f unda-

172

C, B. Davenport 19

mentally different possible theory of adaptation, and this is that the structure existed
first and a fitting environment was sought or fallen into by the species having the
peculiar bodily condition. Thus the adaptive result is, on this theory, not due to a
selection of structure fitting a given environment, but, on the contrary, a selection of
an environment fitting a given structure. I shall now consider some special cases
that are best explained on this theory. Thus, Eigenmann (1899) shows that the cave
fishes, which in many points show an adaptation to the cave environment, are not to
be thought of as having accidentally got into caves and as having subsequently gained
a structure fitting them for that environment. But, on the contrary, as they all belong
to one family, their getting into the caves was evidently not an accident. Moreover,
this family includes species that are structurally especially fitted for cave life, even
when they occur in regions where there are no caves and never have been any. They
shun the light, and live in crevices and under stones. Their bodily conditions fit
them for cave life and when, in their constant search for dark holes, some of them
succeeded in getting into caves, they naturally thrived there.

Again, in many cases of parasitism among snails the radula is known to be absent
altogether, and this has been accounted for by Cooke (1895) on the hypothesis that
these snails lost their teeth through disuse. However, it is pointed out as a curious
fact that the same absence of a radula occurs in species of Eulima known to be not
parasitic. Cooke suggests the hypothesis that in cases like this the form must have
derived from parasitic ancestors. It is equally probable that Eulima is a mollusc
that will probably soon be driven to parasitism because it has no radula.

Now, that which is true for the cave animals, and probably true for edentulate
snails, is illustrated time and time again in the animals of the beaches. We have seen
that the Anurida are covered with fine hairs, which enable them to float upon the tide
and thus keep them from drowning. Are not the fine hairs a remarkable adaptation
to the necessities of the situation ? They certainly are, but the probability is that the
hairs were not developed to meet this situation at all ; at least, such a coating of fine
hairs is widespread among Collembola, and the hairs subserve a variety of functions.
Thus, Schaffer (1898) finds that the long hairs protect the animal against the action
of the sun's rays in the case of certain species that live on leaves; and the importance
of such protection would seem to be great, for Absolon (1900) finds that certain cave
forms of Collembola, which, so far as he describes them, seem to be scantily covered
with hairs, are killed by a few minutes of exposure to sunlight. Hairs are, we may
then say, common occurrences on the thin-skinned Collembola. The hairs are impor-
tant to keep the thin skin from desiccation. Because the skin is thin, the Collembola
favor damp or wet places ; just because they are covered with hairs, they can float on
the water; just because they can float on the water, they can live on the lower beach.
Also, they find 'here their appropriate food. Having by some means got to the beach,
they remain there, because they find the conditions existing on the beach peculiarly
suitable.

173

20 The Animal Ecology of the Cold Spring Sand Sp^t

This law is illustrated again by an inhabitant of the upper beach, Oniscus,
Oniscus seems, on the whole, rather poorly adjusted to a terrestrial life. Its gills lack
the well-developed tracheal chambers of the wood louse, Porcellio, and the pill bug,
Armidillidium, its close relatives (Stoller, 1899). Correspondingly we find it only in
moist situations, under logs, in cellars, in greenhouses, etc. On the other hand, Por-
cellio ratzburghii, Brandt, is a species in which all five pairs of outer gills possess tra-
cheal chambers. As Stoller (1899) remarks: " This species lives in situations where
the air is charged with moisture only in a moderate degree in excess of that of ordi-
nary atmospheric air. Their habitat is under the bark of dead trees, and they may
often be found a meter or more above the ground." Now, experiments that I have
made show that a water-inhabiting isopod (Asellus), if taken out of the water, will go
back into it if free to do so; and Porcellio, if put in water, will leave it for dry
land, if free to do so. Similarly we may conclude that Oniscus chooses a situation
that affords the requisite moisture. Shall we conclude that the reason why Oniscus
has no tracheal chambers is the result of its living in a moist situation, or is it the
cause? We find it where it is because it is hydrotactic. Now, is it hydrotactic
because it has no lungs, or is it without lungs because it is hydrotactic? Certainly it
would be rash to assert the latter, even though we cannot prove the former.

So likewise we find Nassa, which has a siphon to enable it to draw pure water
from above the mud, living in the mud ; whereas Littorina, which has no such siphon,
clings to the stems of the marsh grass above the mud. Can we say that Littorina has
no siphon because it clings to the marsh grass, or does it cling to the marsh grass
because it has no siphon ? I maintain that the latter is no less true than the former.

Let us consider still one other case. We have seen that the mussels cling to the
banks of the channels in such numbers as to make a protecting wall. Of the advan-
tageousness of that situation for the mussel as a lamellibranch there can be no doubt ;
abundant food and oxygen are brought to its doors every day. The wonder is that
no other lamellibranchs than the mussel occupy this favorable situation. Why is this ?
It is because the mussels are the only species living about the sand spit that have a
byssus in the adult stage. Lacking a byssus, the other species cannot attach them-
selves to the banks. Now, does Mytilus have a byssus because it tends to attach itself
to banks, or, being provided with a byssus, was it led to take advantage of the favor-
able position offered ? Did the 'situation or the organ precede ? In this case we may
see, I think, the necessity of the organ being well developed before the special habit
(of attachment) could be exercised. However, it is quite likely that the byssus has
been improved in the race by selection, and with every step of improvement the race
has been able to take up a more and more advantageous habitat.

This brings us, indeed, to the most reasonable hypothesis of adaptation, namely,
the combination of the improvement of the organ to meet the requirements of the
environment, through selection, and of improvement of situation to meet the abilities
of the organism. There have gone on, hand in hand, a selection of more appropriate

174

C. B. Davenpoet 21

organs and of more congenial habitats. Adaptation of organization to environment
has been effected by the double process of selection by environment of the most appro-
priate organization and by the organism of the most congenial environment.

This hypothesis, I think, should be welcomed by those palaeontologists who, like
Osborn (1897), are led from their phylogenetic studies to conclude " that there are
fundamental predispositions to vary in certain directions." They help out, too, I
believe, the fundamentally important observations and experiment of DeVries (1901),
who finds that race change is a series of steps, of mutations, that may often have no
relation to adaptation ; the adaptation comes later. For all those theories, in general,
that assume that change of specific structure occurs independently of selection of the
fittest, the hypothesis here proposed must be considered a welcome complement. It
may be well to point out that the selection of a fitting environment is not confined to
migratory animals. It is applicable to all organisms that have a means of dispersal.
The seed that falls upon good ground — the race that gets into a favorable environ-
ment — will survive.

The theory may thus be summarized: The world contains numberless kinds of
habitats, or environmental complexes, capable of supporting organisms. The number
of kinds of organisms is very great ; each lives in a habitat consonant with its struc-
ture. Each species is being widely dispersed, and, by chance, some members of a spe-
cies get into an environment worse fitted for them; others into one better fitted.
Those that get into the worse environment cannot compete with the species already
present ; those that get into a habitat that completely accords with their organization
will probably thrive and may make room for themselves, even as the English sparrow
has made room for itself in this country. This process may go on until the species is
found only in the environment or environments suited to its organization. As Dar-
winism is called the theory of the survival of the fittest organisms, so this may be
called the theory of segregation in the fittest environment.

In conclusion I repeat that the theory of segregation in the fittest environment
does not replace that of survival of the fittest organism, but is complementary to it.
It has this raison d'etre that it shows how unadaptive mutations may become adaptiv^e
if only they can find their jiroper place in nature.

LITERATURE CITED

Absolon, P. C. K. "Einige Bemerkungen tiber mahrische Hohlenfauna." Zool. Anz., Bd.

XXIII(1900), pp. 1-^.
Balch, F. N. " List of Marine Mollusca of Coldspring Harbor, Long Island, with Descriptions

of One New Genus and Two New Species of Nudibranchs." Proc. Boston Soc. Nat.

Hist, VoL XXIX (1899), pp. 133 62.
CooKE, A. H. Mollusca in " Cambridge Natural History," Vol. Ill (1895), pp- 459.
De Veies, H. Die Mutationstheorie. Versuche und Beobachtungen ilber die Entstehungen

von Arten im Pflanzenreich. Leipzig: Veit & Co., 190L

175

22 The Animal Ecology of the Cold Spbing Sand Spit

EiGENMANN, C. " Cave Animals: Their Character, Origin, and Their Evidence for or against
the Transmission of Acquired Characters." Proc. Amer. Assoc. Adv. of Sci., Forty-
eighth Meeting, at Columbus, O., December, 1899, pp. 255.

Emebton, J. H. " New England Lycosidse." Trans. Conn. Acad. Arts and Sciences, Vol. VI
(1885), pp. 481-517, Pis. XLVI-XLIX.

Emeby, C. " Beitrage zur Kenntniss der nordamerikanischen Ameisenfauna." Zoologische Jahr-
biicher, Abth.f. Systematik, Bd. VII (1893), pp. 633-82.

FiscHEB, P. Manuel de conchyliologie et de paUontologie conchy liologique. Paris: Savy, 1887.
Pp. 1,369; 22 plates.

FoLSOM, J. W. "The Distribution of Holarctic Collembola." Psyche, February, 1901.

OsBOBN, H. F. " Organic Selection." Science, N. S., Vol. VI (1897), pp. 583-5.

SchAffeb, C. " Die Collembola des Bismarck-Archipels nach der Ausbeute von Professor Dr.
F. Dahl." Arch, fur Naturgeschichte, Jahrg. 64 (1898), 1. Bd., pp. 393-425, Taf. XI-
XII.

Sempeb, C. Animal Life as Affected by the Natural Conditions of Existence. International
Scientific Series, Vol. XXX. New York: Appleton, 1881.

Shalee, N. S. " Keport on Marshes and Swamps of Northern Long Island, Between Port Wash-
ington and Cold Spring Harbor," in Report on Mosquitoes, North Shore Improvement
Association (W. T. Cox, Secretary), New York, 1902.

SiMEOTH, H. Die Entstehung der Landtiere. Leipzig: Engelmann, 1891.

Smith, E. A. " Report of the Geology of the Coastal Plain of Alabama." Geological Survey of
. Alabama. Montgomery, Ala., 1894.

Stollee, J. H. "On the Organs of Respiration of the Oniscidse," Zoologica, Heft 25 (1899),
pp. 31, 2 Taf.

Veebill, a. E. (and S. I. Smith). " Report upon the Invertebrate Animals of Vineyard Sound
and the Adjacent Waters, with an Account of the Physical Characters of the Region."
Report of the U. S. Commission of Fish and Fisheries, Part I, for 1871-72, (1873),
pp. 295-778; 38 plates.

Wahlgeen, E. " Beitrag zur Kenntniss der CoUembolafauna der ausseren Scharen " Entom.
Tidskrift, Vol. XX (1899), pp. 183-93.

176

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