While serving with the Scripps Institution
of Oceanography in the Line Islands area
during the International Geophysical Year,
I had occasion to make collections of marine
mollusca on several of the islands visited.
As the primary purpose of my presence in
the Line Islands area was to make observations
of a geophysical nature, the collecting of
marine mollusks could only be done at odd
times, so as not to interfere with my regular
work. Nevertheless a considerable quantity
of shells was collected and data recorded.
Because of the limited amount of time I could
devote to shell collecting while on this
expedition, shells as they were collected
were placed into lots, or accessions, with
all shells collected at one time at one place
being placed in one container. Only a minimal
attempt was made to separate the shells into
taxonomic categories and then only in large
lots that could not be placed in a single
box.
Shells were collected on Jarvis Island Latitude
00 degrees 23 minutes south, longitude 160
degrees 02 minutes west; on Fanning Island,
latitude 03 degrees 52 minutes north, longitude
159 degrees 22 minutes west; on Palmyra Island,
latitude 05 degrees 53 minutes north, longitude
162 degrees 05 minutes west and on Christmas
Island, latitude 01 degrees 58 minutes north,
longitude 157 degrees 25 minutes west.
Collections were made of shells found on
the beach, shells picked up on the reef flats,
both by day and at night with a gasoline
lantern. In deeper water on Fanning, Christmas
and Palmyra, fins, facemask and snorkel were
used. On both Fanning and Palmyra I was able
to use my SCUBA gear. A light hand dredge
with 600 feet of line was taken along but
no opportunity presented itself for their
use.
Complete and comprehensive collections could
not be made for a number of reasons, although
my collection is probably larger than any
made in this area. I have a number of new
additions to the known molluscan fauna of
this area but I consider my collection only
a small sampling of the number of species
now living in these islands.
I first visited the Line Islands in 1936
aboard the sampan Islander, skippered by
William (Bill) G. Anderson. While there at
that time, I collected shells in a small
way. From 1936 until I returned in 1957,
I often wished I could return so as to extend
my collection from this section.
This last trip has convinced me that this
area is among the most prolific and productive
sections in the world for the shell collector.
The Line Islands have been largely neglected
to date, so far as comprehensive intensive
collecting is concerned. In fact it is an
oasis for all types of marine life.
I believe the reason for this is their strategic
location. Underwater charts indicate radiating
seamounts and underwater mountains connecting
the Line Islands to other island chains to
the southeast; to the south; to the southwest
and to the west. Thus these Islands become
a focal point for shell migrations from almost
every section of the south Pacific. I believe
that future explorations in this area will
show a greater variety of species of shells
than any similar area in the Pacific Ocean
area.
Another thing about the Line Islands that
attracted almost as much attention as the
shells is the ocean currents. These islands
are in the belt where the equatorial current
and the equatorial counter-current alternately
change the direction of their flow. Upwellings
of deeper ocean waters bring mineral and
other foods for all marine life to the surface
where it becomes available to shallower water
organisms.
Certain excerpts from my diary will help
to explain this last paragraph. "Aboard
the schooner Fiesta, en route from Palmyra
to Jarvis, Nov. 26, 1957, about ten miles
south of Palmyra, at dusk, ocean very turbulent.
Vast whirlpools and upwellings about a mile
in width extend east and west to the horizon.
Apparently the north equatorial current flowing
to the west is on the north of the disturbance
and the equatorial counter current, flowing
east, is on the south of this turbulent area.
Outside of this region of whirlpools and
upwellings, the water is calm with almost
no swells. A strong easterly set (drift)
was confirmed by navigational fixes the next
day."
Again from my diary, I quote: "Aboard
the schooner Fiesta, about five miles NNE
of Jarvis Island. A strong easterly set has
been with us all the way from Palmyra. Now
on mid-morning of Nov. 29, 1957, sky heavily
overcast, light rain squalls all about us;
water becoming extremely turbulent as we
approach Jarvis. As far as the eye can see
in all directions, fish from small mackerel
size to monster tuna are breaking water and
jumping, in a frenzy of feeding on what appears
to be ocean squid which are being brought
up from the ocean depths by huge upwellings
of water that make domes that appear to be
in some cases over 100 yards in diameter
and two to three feet higher than the normal
ocean level. These domes are interspersed
with tremendous whirlpools, spinning at great
speed, spiraling in depressed cones several
feet deep. The air is filled with sea birds
frantically diving into the ocean after squid
and fish.
"Less than 300 yards from the north
reef while running parallel to the north
shore of the island, the Fiesta ran into
one of the larger whirlpools. In less than
five seconds, the boat, a 72 footer, is swung
about 90 degrees and headed straight for
the reef. The next 30 seconds is a little
'hairy,' but the boat is turned and we head
away from the island to get farther away
from the reef.
"Radio contact with Jarvis confirms
the fact that we cannot land on the west
coast, the waves are too high. The only calm
water is on the east shore, where an offshore-submerged
reef breaks up the swells, and landing there
will be possible.
"From our position offshore, as the
Fiesta moves to the east of Jarvis we can
see that the island is in the middle of a
turbulent band of ocean that extends to the
horizon both east and west, with extreme
turbulence all around the island. On the
north side of Jarvis, the equatorial counter
current is flowing east, and on the Island's
south side, the south equatorial current
flows to the west.
"Later, after we had landed on Jarvis,
I noticed the ocean water near shore felt
much colder than usual. This to me indicates
that deep water from below the thermocline
was being brought to the surface."
The turbulences of the ocean currents described
in the extracts from my diary as printed
in the last issue of the HSN undoubtedly
have a great influence on the marine life
of this area. These turbulences bring deeper
water marine life and minerals to the surface
and the oxygen laden surface water is carried
below. While the equatorial currents themselves
do not change directions, the point of contact
between the two currents flowing in opposite
directions, which causes these upwellings
and whirlpools, does change with the seasons
from north to south over a comparatively
narrow band across the Pacific. Thus this
narrow band would carry plankton and larval
organisms in both directions, both to and
from the various equatorial islands.
New discoveries made during the International
Geophysical Year [IGY] may help to explain
questions of marine fertility and the distribution
of species in this and other areas of the
Pacific ocean. For example, look at what
has been discovered about the Cromwell Current.
It flows from west to east, 7000 miles across
the equatorial Pacific to the Galápagos Islands
at a rate of 2-1/2 knots. The top of this
current is an average of 100 feet below the
sea level but it is 2000 feet in depth and
200 miles wide. For a more extensive description
see LIFE magazine for Nov. 14, 1960.
In addition to existing records, during IGY,
many additional depth soundings were made,
and thus was established a much more accurate
picture of the contours of the ocean bottom.
(See LIFE magazine Nov. 7th). Vast underwater
mountain chains, heretofore unsuspected,
stretching for hundreds of miles, sometimes
a thousand miles, in many directions, were
discovered, with only an occasional peak
rising above the surface to form an island.
Along these submarine ranges, seamounts,
"Guyots" and banks form chains
of oases for all types of marine life. With
a very little imagination it is easy to visualize,
under certain conditions, how a species could
"jump" from one island to another.
These mountain ranges could also explain
the reverse picture, thus providing a barrier
which would cause a geographical "break"
in the distribution of a species, or a definite
limit of distribution.
It is well to remember also that the ocean
bottom is in a continual state of change.
The contour of the ocean bottom is not fixed.
Underwater volcanoes intermittently add new
material to the ocean floor. Earthquakes
of various magnitudes constantly signal these
changes.
The amount of water in the ocean basins of
the world is now on the increase with a very
gradual rise in sea level being recorded.
In times past the level of the ocean water
has been possible 2000 or more feet lower
than it is now. With a lowered sea level
in past ages many of the now submerged mountain
chains were either island chains, or very
shallow reefs, or shoals. This fact must
be taken into consideration in theorizing
about the distribution of species.
The Pacific Ocean basin is also known to
be rotating in a counter-clockwise direction.
Measurements at the San Andreas Fault in
California indicate a movement of at least
350 miles. This rotation would place Pacific
island chains in a relatively different geographic
location compared with their position in
ages past. This would mean possible changes
in the ocean currents affecting the islands.
It might also make a difference in the prevailing
winds over the ages. This is another factor
in the distribution of species.
This old world of ours is in a continual
state of flux and it is conceivable that
this could account for the distribution of
species not explained by conditions as they
exist today. A coordinated study of both
oceanic physics and biology might furnish
the keys to unlock the treasure chests of
new knowledge of each of these widely separated
sciences. With this newly acquired knowledge
it would be possible to recognize a time
in the world's history when conditions were
right to extend the geographical limits of
marine organisms. Conversely we would find
a time when conditions made it unlikely that
further influx of larva, etc., into an area
would be possible. But once we possess this
knowledge, it would help explain the distribution
of species, as well as the evolution of both
subspecies and new species.
The non-pelagic marine mollusk is an ideal
subject for study because of its comparatively
short planktonic veliger stage. During this
period it must find a spot to settle where
conditions are right for it to live and grow,
while almost anchored by its heavy shell.
A study of the underwater bottom contour
differences between the Atlantic and the
Pacific will show a vast difference between
the two oceans. In the Pacific the non-pelagic
marine mollusk enjoys a vast area of distribution
with attendant evolution of new species and
subspecies; conditions which do not occur
in such abundance in the Atlantic.
Another factor in the Pacific that would
tend to introduce isolated colonies of certain
species to areas beyond the reach of regular
distributional channels would be flotsam
(pumice, logs or other debris) carried by
storms and winds in unusual directions. These
could transport adult organisms as well as
larva and plankton.
Isolated populations tend to evolve faster,
producing new species and subspecies. Here
in Hawaii, witness the following: Cypraea
tessellata from C. isabella, Cypraea sulcidentata
from C. arenosa [=schilderorum] and Cypraea
granulata from C. nucleus, to name only a
few. Isolation can be both by accidental
introduction of a species and by geographic
or oceanographic changes that would cut an
area off from a previously normal channel
of communication. However brought about,
the order of the age in the new location
is "Adapt" (evolve or die). Conversely,
in an area at the center of distribution
of a species and particularly if it be a
numerous or common type, evolution proceeds
very slowly if at all.
What It's All About!
The author spent 13 months during the International
Geophysical Year making observations and
conducting experiments for the Scripps Institution
of Oceanography of La Jolla, California,
on what are known as the Line Islands of
Palmyra, Fanning, Christmas and Jarvis. Already
an experienced shell collector, he spent
his spare time in furthering his hobby. Although
he collected an estimated 250,000 shells
during his stay, he became particularly interested
in dispersion and the background factors
which influenced it, such as the ocean currents,
their seasonal changes, the turbulences,
the contours of the ocean bottom, storms,
etc. In the present installment, he describes
a terrific storm which, while it probably
had its effect on shell life, also almost
wiped out the expedition of which he was
a part.
Changes in the size and shape of the land
masses both under and above water, are going
on continuously. During my stay in the Line
Islands, I noted a number of geographical
changes that had taken place since the maps
and charts had been made of this same area,
15 to 40 years before. Some of these changes
had been brought about in the space of about
a week or ten days starting Tuesday morning,
January 14, 1958, when a storm that originated
in the north Pacific a day or two earlier
sent extremely high waves to the Line Islands.
I was on Jarvis Island during this period
of high surf that continued for three days
and nights at a very high level, before starting
to subside. Fortunately for us on Jarvis
Island, and the other people on the other
Line Islands, this storm did not coincide
with the times of the January spring high
tides. Even as it happened, I was extremely
concerned for our safety. To put it in plain
English, I was scared stiff.
Perhaps some extracts from my dairy covering
this period will help you to understand the
situation:
Jarvis, Jan. 14, 1958. Up at 5:30 a.m. Cook
breakfast, clean up afterwards, take surface
weather observations, check chronometer against
WWVH (Bureau of Standards radio station on
Maui, which broadcasts time signals). Change
the photographics film record on the "Askania"
magnetograph. Start 800 cycle generator for
8:05 a.m. radio schedule with Palmyra and
Fanning. Transmit local weather data to Palmyra.
Jack Wheeler on Palmyra reports hearing heavy
surf on the north shore of Palmyra and stands
by for Martin Vitousek on Fanning Island
who comes in and reports the Hawaiian Islands
are being pounded by very heavy surf on their
north shores, starting the night before and
still increasing. A look out of the window
of our house on Jarvis shows abnormally high
surf. We figure we have about 10 to 14 hours
lag behind Hawaii for high seas from the
north Pacific. We sign off and prepare to
dismantle the tide gauge.
This was located about three-quarters of
a mile NNE from the house, on the shore at
the Millersville landing just below the lighthouse.
Because Jarvis has no protective waters the
tide gauge is an unusual type. A mercury-column
balanced-syphon with a metallic lead float
in the mercury pool. The float is connected
with the Bendix recorder, the whole assembly
being a mixed-up conglomeration of valves
and fittings. This assembly is fitted into
an instrument shelter of sturdy wood construction,
bolted and concreted to a large coral limestone
block, located about 100 feet from the shore
and about 14 feet above mean sea level. A
heavy plastic hose extends 200 yards into
the channel, anchored by heavy weights.
Again from my dairy: "On the way to
the tide gauge walking along the rim of the
west shore, we (Otto Hornung and myself)
see heavy surf along the reef and onto the
west beach. (The reef here is 100 to 150
yards wide, the beach is about 100 yards
wide and the rim is 20 to 25 feet high above
sea level). At the tide gauge, I removed
the Bendix recorder and Otto takes it up
to store in the lighthouse. As I start to
demount the main part of the tide gauge,
I see that the waves are getting higher all
the time. Just as Otto gets back, a huge
surf rushes up the beach and engulfs us.
We are up to our necks in foaming seawater.
Chunks of limestone and coral hit our legs
as the water recedes. It is all we can do
to hang on and not be swept out to sea. Then
we worked frantically to salvage the tide
gauge. We see another swell moving on the
horizon and as it approaches the island we
both run up the beach to the rim. The wave
smashes into the outer reef edge, boils over
and races up the beach. We are now at the
lighthouse. The tide gauge is engulfed in
swirling foam and disappears under the rising
water. The wave front rushed up the beach
and over the rim. We are up to our knees
in water which carries inland for about 200
yards before slowing down and draining into
the central basin of this saucer shaped island,
leaving white beach sand, coral and heavy
limestone blocks that were carried up over
the rim. On the beach side, as the wave recedes,
we note that the tide gauge is gone. The
limestone slab, about three feet thick, by
six by eight feet size is gone also, and
the whole beach topography is changed. This
is no place to be, so we head back to the
house which is somewhat back from the rim
on the west side about 150 yards from the
southwest point of the island and away from
the violent north shore.
We reach the house but the sea is still rising
so we start to move the equipment from the
rim to farther inside. There are two solar
stills to furnish fresh water from salt water.
Each still gives about five quarts of fresh
water a day. They are constructed of fibreglass,
resin impregnated, with roof-shaped glass
tops, four by eight feet, and 30 inches high.
These stills sat upon four upended 50-gallon
drums and are located on the rim about 50
yards from the house. We carry one still
inland behind the house and start back for
the other. About half way there, we see a
wave rampage up the beach and hit the remaining
still so hard that it just seemed to explode.
This happened about 11:15 a.m. The tide gauge
had been washed away about 9:30 a.m. No lunch
today. Carried emergency water, food, bedding,
etc., inland all day and weather-proofed
electrical generators and radio gear.
The spray in the air is so thick we can hardly
make out the lighthouse at times but can
see that the north shore is being constantly
breached by the waves pouring over the rim.
At 4:30 p.m. a wave broke over the rim in
front of the house and sweeps around and
into the house. We had been moving the gear
inland and are caught just back of the rim.
The water rises up to our necks before it
subsides. I find sand and pieces of coral
in my shirt pockets. Pieces of coral and
limestone slabs 2 to 3 feet thick and up
to 10 and 12 feet in length have been carried
as far as 400 yards inland. One of our lead
plate storage batteries has been carried
inland about 300 yards. We have lost a lot
of our gear, with high damage to a lot more."
Synopsis
This series is devoted to the marine shells
and the conditions in which they live, on
the so-called Line Islands of Palmyra, Fanning,
Jarvis and Christmas those tiny mountain
tops which emerge from the Pacific Ocean
some 1500 miles south of Honolulu. Previous
installments described the location of the
islands, the ocean bottom in that neighborhood,
the mighty currents flowing in opposite directions
and the turbulences which arise where these
currents pass each other and in our last
Issue a terrible storm was raging as the
installment closed. In this issue [are given]
some of the visible effects of the storm,
in subsequent issues, maps of the Islands
with shelling areas, and later checklists
of the various genera.
I condense some of the entries concluding
my diary of Jan. 14th, 1958. "We cannot
see the waves now (after dark) but the sound
is ominous. We hope the house is not struck
by any of the large coral slabs. There is
no place to hide. There are no trees or brush
of any kind on Jarvis to hang on to. We do
not sleep. Waves at intervals break over
the rim (20 to 25 feet high). We are struck
again and again. Once at 9:15 P.M. Again
at 10:03."
Still quoting from my diary: "Midnight,
start of Jan. 15, 1958. Storm continues.
Struck by waves at 12:59 A.M.; at 4:00 A.M.
and again at 4:50 A.M. Dawn is breaking.
It's been a long night; Feel better in daylight.
Waves swirl around us at 6:45 A.M. and again
at 7:21 A.M.
"Radio contact with Palmyra and Fanning
at 8:05 using our emergency radio. Palmyra
reports that water two feet deep has been
pouring over the north side of the island
and into the lagoon. On Fanning Martin Vitousek
reports considerable damage. No details.
Another wave breaks over the rim (on Jarvis)
and surges around the house at 1:15 P.M.
and again at 10:24 P.M."
"Midnight, starting Jan. 16, 1958. 5:10
A.M., No sleep for the second night in succession.
No more waves are breaking over the rim near
our house, but daylight discloses waves still
breaking over the north rim. This continued
for the rest of this day. Reef and beach
areas are a surging, swirling, seething mass
of white foaming water. Large pieces of the
reef and of cemented coral limestone are
being carried over the reef and deposited
on the beach. The contour of Jarvis is somewhat
changed on the southern side of the southwest
point. A peninsula of sand has built up 8
to 10 feet above the ocean level. It is over
200 yards wide (east to west) and extends
south over 100 yards". A few days later
when the sea had become calm again, I could
stand at the end of this sandy peninsula
and look down to deeper water off the reef
slope. The upper portion of this sand bar
was the most productive beach-collecting
area on the island in the months to come.
A very heavy salt spray mist blankets the
north shore of the island. Although the worst
seems to be over the waves are still rushing
almost to the rim in front of our house.
We don't sleep any for the third night in
a row.
Dawn on the morning of Jan. 17th discloses
that the waves are coming on only half way
up the beach for the most part, a few occasionally
rising two-thirds of the way up. We are very
tired and decide to take two hour naps, by
turns, one watching while the other slept.
Otto sleeps first and I take the next two
hours. When not sleeping we spend the time
for the rest of the day cleaning up around
the place and putting our gear in working
shape. We hit the sack early.
Saturday, January 18th the surf was still
high but it was subsiding. In the afternoon
I took a walk along the west beach, to the
site of the tide gauge installation. I hoped
to find enough salvageable parts to put it
in operation again. The only things I found
were bits and parts of the instrument shelter
scattered far and wide, some three to four
hundred yards inland.
I walk farther along the shore to just beyond
the northeast point of the island. From here
I can count in the space of half a mile,
seven peninsulas made up of coral shingles.
These vary from 100 to 200 feet wide, from
150 to 300 feet long and from 15 to 18 feet
high at the shore end, tapering off as they
neared the seaward reef edge. In the weeks
to come these were to prove excellent collecting
areas not only for dead shells but for live
species usually found in deep water. The
water is still too rough to be able to wade
on the reef.
On the way back I take note of more changes
on the western section of Jarvis. At the
northwest point on the high rim, a 12-foot
high by eight feet square base pyramid pylon
of coral and limestone is completely gone.
Along the whole west coast coral slabs have
been carried inland and clean white sand
has been washed over the rim for a distance
of 500 yards. Jarvis is dish-shaped in that
the rim is higher than the center. Following
this storm there was a lake or land-locked
lagoon in the center over a quarter of a
mile across and I estimate a depth of 5 to
6 feet.
In the Millersville landing area, almost
every evidence of the Hawaiian colonists
(Kamehameha School graduates) has disappeared.
They were on the Island from March 26th,
1935, until after the start of World War
II, but not a trace remains now. Only the
very solidly built lighthouse is still standing
in this area.
The house foundations, cisterns and other
ruins of the guano diggers (Feb., 1858 -
July, 1879) are completely eradicated. Seeing
all the damage caused by the fantastic power
of the rampaging sea makes me glad to be
still alive. We are uninjured. Our house
is intact. Our food supplies mostly came
through O.K. We still have about 300 gallons
of water left, in five gallon cans and in
our water tank. However we will have a lot
of work to do to get back into operation,
but that's what passes the time here. One
comforting thought however cheers us. I don't
believe we'll have another storm such as
this while we are on Jarvis. Although the
Island shows evidence of even worse storms
in ages past, the guano digger's ruins had
been standing for almost a hundred years
until wiped out by this storm.
Author's Note - Mr. Edwin H. Bryan, Jr.,
curator of collections, Bishop Museum, has
very kindly put me in touch with some of
the original colonists who were on Jarvis
Island prior to World War II. He has also
granted permission to use any of the interesting
and valuable data from his book "American
Polynesia and the Hawaiian Chain". During
my stay in the Line Islands, I found this
book a gold mine of history, natural history,
geology, geography and human interest, complete
with photographs, maps and charts of the
Line Islands as well as the islands of the
northwest Hawaiian chain, the Phoenix, Samoa,
Tokelau and other island groups of the tropical
pacific. Copies of this excellent book are
available at the Bishop Museum Bookshop.
I am also indebted to Mr. Paul Gordon Phillips,
who was on Jarvis at the start of World War
II. Mr. Phillips has very kindly furnished
data to fill gaps in what was available until
now. Mr. Manuel Pires, past president, and
Mr. Marvel Smith, president of the "Hui
Panalaau," the society of former Line
Island colonists, have both been very helpful
with information.
Figure 1, page 1, the chart "The Line
Islands and Their Relation to the Hawaiian
Island Chain" is reduced in size to
fit the format of H.S.N., the 3 degree grids
are 207 statute miles apart (180 nautical
miles). Distance to Honolulu from the various
islands is given in statute miles.
Prior to the January, 1958, storm, I counted
13 shell holes on Jarvis, most of these were
eradicated by the storm. Judging from the
size of the craters. Approximately 12 to
18 in. diameter and five to eight feet deep,
it appears that they were made by a shell
of at least 5- to 6-inch caliber.
On the north shore reef there are coral encrusted
metal ship fittings cemented fast to the
reef. These appear much older than their
counter parts on the south shore. There is
located the wreck of the Barkentine Amaranth,
that ran aground on the night of August 30,
1913. I can find no record of the apparent
wreck on the north shore.
The scale on the Jarvis charts (Page 7) is
reduced to fit the format of H.S.N., however,
the parallel grid lines (minutes of arc)
are one nautical mile (or 6080 feet) apart.
Close inspection of the topography of Jarvis
seems to indicate that the island was once
horseshoe shaped with a lagoon opening toward
the east. The lagoon gradually filled in
and a low rim has built up on the east shore.
Gravity - metric measurements made on Jarvis
during I.G.Y. indicate a mound or peak, underlying
the island, of dense mass, probably volcanic
basalt. If this is so, then Jarvis is a relatively
thin overlay of coral limestone on a submerged,
extinct volcanic formation. The surrounding
ocean bottom drops abruptly to a fairly even
ocean bottom at about 2800 fathoms (16,800
feet), in all directions except to the east
where the depth increases more gradually.
Figure 2, page 7, "Jarvis Island".
The unspecified figures offshore are depths
in fathoms. Note that I have marked the location
of some of the remaining shell holes (not
sea shells). These were made at the beginning
of World War II by a Japanese submarine that
surfaced off the west shore of Jarvis. The
four colonists on the island thinking this
was a U. S. Navy submarine that had come
to remove them, rushed down the beach joyously
waving their arms. The sub unlimbered its
deck gun and commenced to fire upon the completely
defenseless, unarmed colonists. Fortunately,
due to poor marksmanship, no one was hurt.
The colonists scattered and ran, hiding inland
on the island.
Mr. Paul Gordon Phillips of Kailua, who was
a member of the last colonist group on Jarvis,
tells me the reef surrounding Jarvis and
particularly the reef on the north shore
abounded with tens of hundreds of living
Tridacna clams, a good portion 18 to 24 inches
long. In contrast, during my stay on Jarvis,
I walked over and searched for shells on
every foot of the reef around the island
and I saw only four live specimens, these
being on the south reef. I collected two
specimens and left the other two undisturbed.
All four were only 12 to 14 inches long.
Mr. Marvel Smith and Mr. Phillips both report
many reef octopi in the mid-1930's, yet in
1941 Mr. Phillips saw only one and I saw
none. What caused these changes?
EDITOR'S NOTE:
This is a continuation of a series of articles
by Mr. Jewell which appeared in the HSN in
1961 [maps]. The author spent 13 months during
the International Geophysical Year making
observations and conducting experiments for
the Scripps Institution of Oceanography of
La Jolla, California, on what are known as
the Line Islands of Palmyra, Fanning, Christmas
and Jarvis. Here he tabulates the various
species of Mollusks showing on which of the
Line Islands they occur and their frequency.
CLASSES OF MOLLUSCA REPRESENTED
Gastropoda (univalves): This class was well
represented in the Line Islands not only
in the variety of families and species but
in the abundance of most of the species.
As a result this report will deal primarily
with the gastropods.
Amphineura (chitons): No specimens of this
class were collected by me during my 1957-1958
stay in the Line Islands.
Scaphopoda (tusk shells): No specimens of
this class were collected by me, probably
because no dredging was done in the deeper
off-shore waters.
Pelecypoda (bivalves): Although I collected
representatives of this class in the Line
Islands, the number of species is small when
compared to the gastropods.
Cephalapoda (squid, octopus, nautilus): One
unknown specimen, order Octopoda, genus Polypus,
was collected on Palmyra. Several cuttlefish
"Pens" were taken on Jarvis. Two
dead specimens of Nautilus pompilius Lamarck
were collected on Jarvis and another dead
one on Palmyra. These had probably been carried
many miles by ocean currents and showed evidence
of being dead a long time.