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NEAR STOCKT —

| WINFRED EMORY ‘ALLEN .
& 7 “ x t sy A
Vol. 22, pp. 1- 292 :
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AEMMTHSONIA ry
OCT 4 1988
LIBRARIES

A QUANTITATIVE AND STATISTICAL STUDY
—— |
OF THE PLANKTON OF THE SAN JOAQUIN
RIVER AND ITS TRIBUTARIES IN AND
NEAR STOCKTON, CALIFORNIA, IN 1913/

BY

WINFRED EMORY ALLEN

UNIVERSITY OF CALIFORNIA PUBLICATIONS IN ZOOLOGY
Vol. 22, No. 1, pp. 1-292, pls. 1-12, 1 text figure
Issued June 25, 1920

CONTENTS

PAGE

rita WChlOMs cess eesce secs acess PR RRR co Ne Mire ere Aiton Wiser crete 4
(Ateknowiled ements) ie ssteamisrties.ssecceisecvters ccodeetoss tecscies RP setae axes diese lest eee Nanos bees 5
General features of San Joaquin River basin.. 6
Generall Chana CheriSplcs mere fo srce eteeacctastokvates 2s cscs sexete sates aiciaceseeeeeivcnesars sR AAS 6
NTO CSA BLO Tver ere EC Meee ce sec cate aaeee sat era lcanhseaicies sacusvysuestauseewveviacesceasbneve dcareay deers 7
SimilarseOrT Ap Mice OCALILIES My sewer ope tencctetesesce szccerecectrte- eevareeene ae racessever crac 7
Geographie’areas of middle C@aliformiay.........c..c..cccseccensesccseesseneccsrevseesezsseeseree a

Size and form of San Joaquin drainage area. 7

PH GLO TAALCAS Renee. clear cancereee Dene eset ana eae ceasc vac aner sas Sorscscactedegnerueadscsteoutasveswecest 8

HE exarn Feil operat mecaen Bet ee 8 Socny cine ops eaated ca searrc Sere as hacevaaceeastocvosnie reas phe Seeman CAE 8
Important tributaries of San Joaquin River 8

dMbe gain ps Rity er sen cc cceacteceteetesscarsaccoressecsateessi sae pcsvacsesctsveesaccdvecveteseceacedetce 8

The Merced River 9

sewn ol ummeme aE abyeleerrceseester cone fect er ceee ero ese see eater casero eacus es sees . 9

Pues SS GAUNTSD SUIS HELV OD ose casscessasces sects sees eet cece ee ere eee Seana tae as vsnadieeacePot 10

hei Calaveras Raviercsescc.ssccastseactete testers See aL)

MUNDI yao eee ne rer: bo, odes sckecstnseaatinaee etree 10
Biv ereCOUCIMORS ME AIT SLO CHUOM ac cecsctescsesrcons cere cone recceee ce senc sons ecm cone eabe erect eee 11
Relationsois tockton bomb Ge=wAbeL: cesses eer ce ctence scenester sence cece a fealil
RivemoradientsADOVE IS bOCKLOMMe tn cette teerert aresccescscscee cesses oreereoseere eee ~ dil
Opportunities for plankton development 11
Miffectiotphenmountalms\ercc estes .tcses.cstevseececssteseatene ss ss.teroreeee 12
MOTT CLAUS Me stress ere eee reat etal vate naeneec eee IS Sateas 12
LAY tise; anasscktt epee SB ec edo Se PERE SPEER Orne ic eon sc oe 13
ANTI CGRTRESLSY OLS sas ote ate ac OR eee PE AOC So nC ENE cr eto ee eee ls
Chemical conditions not studied. 14
DETOGLS) a ae eta hae 85 AN FIN WS ar ee oR ee Reel eee, . 14
Aquatic and marginal vegetation.........0.000000000000...... Peeves eet rere ea Le
PihesCollectingistationse a ememetere ernie cetera neh Renee ete Mee ie 15
Station I... 16
Station IT.. 16
Station III 16
River currents and depths............ 16
Comparison of stations... oetcnesineitn soe uite ees 16
Methods of securing data.. z Saeed Ase earls
MITE FO fs Coll Cctirn ater meemen see tye esse scars Face sik cova ca ESS UT SET es oot 18
se ROL olen e tee meemernen merece eee ces ace anes Sack vtnn aR Wl oN toctesiaphciascaeceess 19
sPrevamount) ofshaul mayen cc cere eave Seca eee eee ee een oe 20
Depth and rate of haul Paiste eee eee i nn 20
EVE COLE eient oot meee: ORE ne NaN As SAGES Ooh ce PAE cit ont Me he Ne 20
Preservation of material........0...00.00..... PRR eR oa ER ee ARN NDR SNS 2 ea oe 21
Hestsvolgsalinity serene meer eterna ewe ee ernst er ree MS oar oe oe: 21
Measurementiotav,olUme st tnthcinc tiene Me scat te cdccuca tre sere ones heat ses eocsecixne 22
The enumeration 22
PAT) AT SUG US eeeress te erent ett anes Ba rub mectcosee i eansome patie ee oe eee 22
ETO CE GUT C mermemn ee earned tite caves cities eeesins uptake teeta hao Oe 23
Standardéconcentra tions seetreeci ee acc science se Se reer cece oe 23

bo

University of California Publications in Zoology [Vow. 22

PAGE
Making and recording the count..........0....0..00000000-. fis ascaseeseren eee 23
Computation and tabulation.......00...000.ccccccw sastodesesostcse sO 24
Mid ertatt cation ob fOr ssyecsscrctesaty cece avsscrerescshanstssseaeosesereceesecsetete te 24
SHIM SHON OL SI GinctMeerecesseconsseeentereeeret<cmsece casos see sis sescrascuveesves te ee 25
Mherclog ging Of the! netiacc.c.-cscssacarvscssecasvsetsrscecvscsss ss ; ier 26
Wolumetnierd atin. settee amerecetecttetis Pe cus: 26
Organisms found in San Joaquin plankton. ..........cccccsscscccesscsseescsssescseccscseseseseseeeesensns 27
LD Y=tabav tito) riser embesss utero masa reecsierrpascnet cers cnet Soca Se eee MEPREEEET SE 27
Componentitorms fice asnicrtir con coat we) (a
The principal types of fresh water planktom........0.000000.000.00c0c . 28
Major groups of plamktoniyccc..sssrssccorsecesecereerere 5. luhel Seas kee 29
PUB Ae le, nc cestnaceoacencssaneap <otventeetaoet cose ee wees Coa Ee NEM e UN ERE RCE PR esas v0 obo dace say ceotsaee 29
Zooplankton’ fre. ce cstiaseatedsecnaace hee ee eo Bre scene avelaustucsacn ters 29
Totals! ofanayjor!CrOUPS) kc scccssen oe acee eee be cons tastns oetnci tees 30
Comparison with similar groups of Illinois forms....00.00.00000.000000000.00.000cce 32
Detailed discussion! of)statistics).....csssese ee eee eee eee 33
AVR G ccc se cca deaccstuadesestencsess saeaespanssacvonseng Fe Get ee eR ROR RR 34
1 BEKei 2) 9) 212s eee ee en ER an 4 coh Soulo- rubs Koseceanr Poop 34
Schizophyceae
Discussion: Of SPCC OS:..<.<asscsséscccaceossasecneecocduestvceoss ease ee eee tae Te Tee ORR
Chlorophy cese ser. scz.2cs saecas sexes exatchvsi fences adaces 5.0 en 38
Discussion Of SPECIES: s.. <<<... 6:-s¢csocececscessssenesssteesuseews soe ces ANPSESER toc RRL Cette oR oR 40
Baeillaria cee. o7cc8.ci.sapesciccaseeatactsscsevauavesa soseaveracth con ial eucned Roe 46
Discussion of species = » 49
Conjugataergnc.cs Las BR nea eb aa a biaUaPAWaues saps eoenook Mae cea 62
Discussion of species.................... sSacedvach Sarmpagest erates Meant ss avast ncsstecas cae EOC 63
Chlorophyll bearing organisms and Mastigophora......00.00..0.0..0....00000... 64
ProtozOsher erences siald cote eee toeeverutrage teeter bas sesper aaa ree ae 66
Mastigophora. eo
Discussion of ‘SpPEGleseeeceessserssckx. yccc< vs ehes eseek sees aR RE et re eT 68
RI ZO PODER eck ses acscsete Sere Oe OE oe ee 75
Discussion of species.
Heliozoa....
Discussion of species tee oo *
MG... crecct cee ca cnaau tac sohics jancesuiv sone /oseua eee teevat odes Watvensciascask RR eae eect
Discussion of species
Suctoria....

Rotifera....
Rhizota.....
Discussion of species..... ste
18%0 (cll Coy to €: eaeeene cee eee eer oc eee eer reer rt ea ro icrain: axcecoosecun«
Discussion of species
Ploima.......
Discussion of species... pecae =
SSCL tO NO Bice sacesase ce vera ce renee ce sctt casss jesas sce nesesveze Seep RMON COR Rr tenet care 106
Gastrotrichaeeee se mires Bee access sucvcrreeetee Fence to cites
Entomostraca ; a
CG) Eis Fay etc: epee rr per eigen cee See CLP EEE ECRECEE Pree Per Fins, et So OL Ucce nsession:
Discussion of genera
Ostracoda
COPE po sic ccacscstzecqeacceeonoremeereeesae suze stecsstekysiscone avenues arin teste Re eee

1920] Allen: Plankton of the San Joaquin River 3

PAGE

IDYSUSEO NOTE TVET, orcsesyerp gcrec dc crP ec ee Rote eI aE oe ere oo 109
Malacostraca... soo HUT
INTIS Cell an GO Us tees seers coi eetceas scenes crasrstenet is Se acseaca seo itil

pli erdarliys Seri esis teeter eee ten eee eves acs arrose ecsece access ve WE
Summary “SAO ator icc ey RR a er eon ae Ae Ne 116
mMbephourly: series ec sane eevee sien: colschesonte itty etese 117

(Conclusion sete tee en el ae a Lee URE

Tables 1 to 8....
Literature cited...

4 University of California Publications in Zoology |Vou. 22

INTRODUCTION

The biology of fresh water is an attractive field for investigation
both from the standpoint of ecology and from that of its practical
bearings on the problems of fisheries. The fresh water plankton with
its varying components forms a biological complex, or association of
both plant and animal forms which have an intimate relation not only
each to the others, but also to the varying factors of their environment,
such as light, temperature, organic and inorganic substances in solu-
tion, and to seasonal change attendant upon the run-off from the
watershed.

The survey of San Francisco Bay undertaken by the United States
Bureau of Fisheries in 1912-13 in codperation with the University of
California afforded an opportunity to initiate a survey of the plankton
of the San Joaquin River, one of the principal tributaries of that bay.
My position at Stockton as teacher of biology in the High School
afforded some laboratory facilities and also a location near the head of
tidewater where the ultimate contributions of the stream of the bay
could be examined and where a variety of conditions were present,
including both the main channel, and backwaters with varying rates
of flow, as well as a canal much enriched by sewage.

The author is conscious not only of the serious and baffling diffieul-
ties that attend such an attempt at a continuous piece of work but also
of the errors which inevitably creep in, especially in the initial stages
of such an enterprise. These errors are, however, in the main, dis-
tributed throughout the data and do not necessarily invalidate our con-
clusions. Such errors as occur in taxonomy are due to lack of the
specialist’s knowledge of nomenclature and synonymy, and of his
critical skill in the finer distinctions of species and subspecies. The
species as I have recorded them are at least groups of recognizably
similar organisms. The largest source of significant error in this
ecological study is the not improbable inclusion in such groups, of
small numbers of less abundant or rare species of closely similar form.

1920] “Allen: Plankton of the San Joaquin River

oO

ACKNOWLEDGMENTS

This investigation owes its origin to the committee in charge of
the survey of San Francisco Bay, of which Professor Charles A.
Kofoid, is chairman, and was undertaken under the auspices of the
United States Bureau of Fisheries, to which I am indebted for equip-
ment of nets and supplies.

Both Dr. F. B. Sumner and Waldo K. Schmitt, successive natural-
ists of the United States Steamship ‘‘ Albatross,’’ have lent their en-
couragement to my efforts and have also titrated some water samples.
For literature, or assistance in securing it, sincerest thanks are hereby
given to Professor S. A. Forbes, of the Hlinois State Laboratory of
Natural History, to the Michigan State Fish Commission, to Professor
H. W. Conn of Connecticut, to Professor H. B. Ward of the Univer-
sity of Illinois, to Dr. Vincente Izquierdo of Santiago, Chile, to the
United States Geological Survey, to the Chief of Engineers of the
United States War Department, to Professor F. E. Clements of the
University of Minnesota, to Dr. Wiliam F. Allen of the University
of Minnesota, and to the Library of the University of Minnesota, to
Dr. C. Dwight Marsh of the United States Bureau of Plant Industry,
to Mr. H. K. Harring of the United States Bureau of Standards, to
Professor C. J. Elmore, Grand Island, Nebraska, to Dr. B. W. Ever-
mann of the California Academy of Science, to Professor E. A. Birge
of the University of Wisconsin, and to Professor C. A. Kofoid of the
University of California.

Dr. Marsh and Mr. Harring have also very kindly made some
identifications of copepods and rotifers. Very material aid has been
given by Mr. EK. P. Higby of the California State Hospital at Stock-
ton, who has given full use of his weather records, and to Mr. Law-
rence Backes of Stockton for photographie views of the stations.
Above all it should be said that whatever value there may be in the
present paper is largely dependent upon the advice, encouragement
and assistance of Professor C. A. Kofoid; and upon the painstaking
eare with which Mrs. W. E. Allen has computed, recorded and _ pre-
served most of the data as they came to hand. Inasmuch as Professor
Kofoid’s report on the Illinois River has been in constant use for ref-
erence and guidance it has been used liberally for suggestive outline
of discussion. Many of its generalizations and conclusions are assumed

6 University of California Publications in Zoology [Vou 22

as applying here, but some points will receive special notice for the
purpose of comparing conditions there and here when the data will
permit.*

GENERAL FEATURES OF THE SAN JOAQUIN RIVER BASIN

The writer has not yet had sufficient opportunity to collect detailed
information on this topic. The California report by Clapp and Hen-
shaw (1909), to the United States Geological Survey, upon the surface
water supply gives an excellent discussion of the most important fea-
tures and it forms the main basis for this present brief discussion.

GENERAL CHARACTERISTICS

Two points of difference from the typical river basin in its latitude
are interesting characteristics of the San Joaquin. First, its drain-
age is northwestward away from the equator. Second, it consists
throughout of a rather deep trough with comparatively abrupt sides
and unusually flat bottom, the level of which is repeatedly broken by the
deltas of tributaries entering in most cases very nearly at right angles.
The land surface.varies markedly in character with the differences in
these tributaries, but with a constant tendency to the formation of
swamps and marshes at the lower points through the deposit of the
lighter organic matter not left in the tributary deltas. This condi-
tion is very prominent from some distance above Stockton on to the
mouth of the river. Stockton itself is on the eastern border of an area
of swampy peat land through which the course of the river can be
maintained only by extensive systems of levees. Even then great
stretches of the lower levels are inundated each year, and Stockton
has the perennial problem of escaping from floods.

It is quite evident from the foregoing that the lower valley as a
whole is fertile, with a deep soil of good texture. The lower part is
fairly well settled but there is as yet no adequate control of the water
supply and an extensive area is practically undeveloped. The few
cities are small and far apart. None of them is so situated as to
cause any appreciable contamination of the river water near Stock-
ton. The whole basin is under the direct influence of the ‘‘dry’’ and
““wet’’ seasons. With its low levels, this results in sluggish, almost
stagnant flow of the main river during the first, and a brisk flow during
the run-off of flood waters incident to the second.

* This paper is published by permission of Dr. H. M. Smith, commissioner of the
United States Bureau of Fisheries.

1920] ' Allen: Plankton of the San Joaquin River

ba |

LOcATION

SIMILAR GEOGRAPHIC LOCALITIES

The San Joaquin River lies in about the same latitude as the larger
part of the Mediterranean Sea, the headwaters of the Tigris and
Euphrates, and a considerable portion of the Hoang Ho, both of head-
waters and lower reaches. It extends northwest from about 35° to 38°
N. latitude between 118° and 122° W. longitude. The main basin lies
on the isotherm of 60° F. Similar average temperature conditions are
found in the Potomac region of the United States, along the northern
border of the Mediterranean Sea and in north central China near the
coast. Stockton lies in latitude 37° 57’ 30” N., longitude 121° 17’ 30’
W. and on isotherm 60° (15.5° C). The altitude at the steamer
landing in mid-city is sixteen feet, according to Mr. A. L. Miner, assist-
ant city engineer.

GEOGRAPHIC AREAS OF MIDDLE CALIFORNIA

The part of California containing the San Joaquin system is a
region of great diversity, but it is quite distinctly composed of three
parallel strips of country. There is the Coast Range at or near the
western border of the state, the central plain known as the San Joaquin
Valley, and the Sierra on the eastern border. The part with which
we are immediately concerned is comprised in the eastern slopes of
the Coast Range, 4,000 square miles, the valley, 12,700 square miles,
and the western slopes of the Sierra, 16,000 square miles. The range
of altitude is from near sea level in the lower valley through some
hundreds and thousands of feet in the Coast Range and the Sierra
foothills up to over 14,000 feet in the High Sierra. The gradient is
slight lengthwise of the valley, very steep, commonly twenty to forty
feet to a mile, to the Coast Range, and generally moderate to the
Sierra, averaging nearly five feet to a mile.

SIZE AND FORM OF SAN JOAQUIN DRAINAGE AREA

The total length of the San Joaquin River is near 350 miles, 125
miles from the High Sierra to the main valley and 225 miles thence
to the outlet into Suisun bay, 50 miles from San Francisco. All the
important tributaries are from the Sierra slopes, which consist mainly
of granites and metamorphic rocks, sedimentary and igneous. The
slopes of the other side are mostly sandstone, shale and conglomerates.

8 University of California Publications in Zoology (Vow. 22

The differences in gradient partly cause an asymmetery of the
valley floor which is made prominent. by the differences of the streams
on the two sides. Since the streams on the east side are larger, they
have built larger deltas with a wider spread as they cross the lighter,
longer slopes. Deltas from the two sides have united across the valley,
cutting off the Tulare basin. For this reason water from the large
streams at the head of the valley does not reach the San Joaquin River,
except in years of unusual rainfall. Thus about one-fourth of the
main basin is practically separated from the rest and this southern
area rarely has any influence on northern conditions.

FOREST AREAS

There is no important forest cover in the main valley. Some of the
higher ground in the Coast Range bears shrubbery and light timber.
The Sierra foothills are usually well covered with grass, brush and
scattering trees. Above the foothills is heavy timber to 10,000 feet,
above which none occurs. The famous Sequoias occur in this region.
National forests occupy about 65 per cent of the Sierra slopes.

RAINFALL

The annual rainfall varies from five to twenty inches from south
to north along the valley. The west slope has light rainfall with simi-
lar increase northwest. The Sierra slopes show heavier precipitation
according to altitude, but with similar increase to northward.

IMPORTANT TRIBUTARIES OF SAN JOAQUIN DRAINAGE AREA

In addition to the foregoing consideration of the main river and
the basin as a whole it is worth while to include some points concern-
ing three or four of the principal tributaries which may have some
recognizable influence at Stockton.

THE KinGs RIVER

The King’s River is the most southerly tributary that has any
ordinary connection with the San Joaquin. Its relation is rather
peculiar since its delta forms a large part of the barrier cutting off
the Tulare Lake Basin from the main valley. This delta has been built
in such a way as to carry the entire flow of the Kings River to the San
Joaquin during low water, but most of the flood waters go to Tulare
Lake. The altitude near the entrance of the San Joaquin is about 175
feet according to Clapp and Henshaw (1911).

1920] Allen: Plankton of the San Joaquin River 9

King’s River basin has fifty miles of Sierra divide as its eastern
border, with some altitudes above 14,000 feet. Its length is about sixty
miles in the mountains, with an area approximating 1,840 square miles.
The river source consists of many little glacial lakes at the edge of
glaciers and perpetual snow. The length of the river to the mouth
of its canon is nearly 85 miles.

The basin as a whole is very rough and irregular, the head espec-
ially including the most rugged region in the Sierra. Nearly all the
tributaries run through glacial cafons cut through solid granite. Sey-
eral of the latter are 2,000 or 3,000 feet deep. The whole formation
is granitic.

The larger part of the basin is well forested up to 10,000 feet
Most of it is in the National Forest Reserve. Precipitation ranges
from eight to ten inches in the San Joaquin Valley to fifty or sixty
inches in the high altitudes. Most of the precipitation of this basin is
in the form of snow.

THE MERCED RIVER

The Merced River drains an area sixty-five miles in length from
Mount Lyell on the Sierra divide (13,090 feet) down to the San
Joaquin River. This ineludes a total of 1,200 square miles. The river
itself is about 135 miles in length, with four or five tributaries of some
importanee, including the famous Yosemite Creek. Though the Yosem-
ite Valley is the most remarkable, there are other parts of the
basin very rough and broken, with many waterfalls and glaciated
regions. About 850 square miles of the upper part of the basin is
included in national forests, though there is little growth above
12,000 feet. The annual precipitation in the San Joaquin Valley near
the mouth of the Merced sixty or seventy miles from Stockton, is ten
to fifteen inches and it ranges through twenty-five inches in the foot-
hills to about sixty inches near the divide. Even in the mountains this
precipitation occurs mainly in the rainy season, mostly as snow, the
melting of which is most rapid in May and June.

THE TUOLUMNE RIVER

The Tuolumne River traverses a basin 105 miles long, two-thirds
of which is in the mountains. The mountainous portion is about
1,680 square miles in area. This river is 150 miles long, about
80 miles of which is through a deep canon cut down into solid granite.
This cafon drains numerous glacial lakes at the Sierra divide, and
the upland meadows slightly lower down. The basin as a whole is

10 University of California Publications in Zoology (Vor. 22

very rough, with bare, glaciated rocks of granite in the upper parts.
Altitudes vary from 300 feet in the foothills to 12,000 or 13,000 feet
at the divide. Upper parts have no forests, but there is a median
belt heavily forested with coniferous trees. The lower region has only
grass and brush, usually. There is about 1,200 square miles of National
Forest in the mountains. Precipitation is about ten inches per annum
in the region near the junction with the San Joaquin, 25 or 30 miles
from Stockton. It ranges to sixty inches at high altitudes where most
is snow, the greater part of which disappears in spring.

THE STANISLAUS RIVER

The Stanislaus River has a long, narrow basin, about 75 miles in
length and an area of somewhat over 950 square miles. The length of
the river is about 120 miles, 80 miles in the mountains. The source is
mainly in glacial lakes about the divide and the mouth is about 20
miles above Stockton. The general character of the basin is quite
similar to that of the Tuolumne.

THE CALAVERAS RIVER

The Calaveras River flows near Stockton and empties six or seven
miles below the city. It has some influence in flood season on account
of the overflow, but in this case its influence would be much the same
as that of those already mentioned since the flood waters of all are
essentially similar. Furthermore, the flood waters of the Calaveras
are largely kept from the San Joaquin above Stockton by an enor-
mous levee forming the so-called ‘‘diverting canal.’’

TURBIDITY

The turbidity of the water of the San Joaquin in the vicinity of
Stockton at all times of the year is very characteristic. In the river
channel this is obviously due to fine silt during the flood season but
the plankton is the principal source in the sluggish water of late fall.
Water in some of the sloughs sometimes becomes clear enough to
reveal objects at a depth of six or eight feet.

1920] Allen: Plankton of the San Joaquin River 11

RIVER CONDITIONS NEAR STOCKTON
RELATION OF STOCKTON TO TIDEWATER

In this connection it is doubtless worth while to reconsider the
points already mentioned which have most obvious relation to Stock-
ton conditions. First, we may emphasize the fact of the low gradient.
Since the steamer landing at Stockton is only sixteen feet above sea
level the water level must be only about eight feet above sea level for
a considerable part of each year. Stockton is about one hundred
miles from the Golden Gate, so the gradient to the sea is only about
0.08 foot to the mile. This must account in large measure for the
range of the tide, which sometimes shows a difference of something
over three feet between high and low water in Stockton Channel.

River GRADIENT ABOVE STOCKTON ~

In the other direction, we find a rise to one hundred and seventy-
five feet above sea level at the mouth of Kings River, probably about
two hundred miles above Stockton. Assuming this distance as an
approximation, we find the gradient above Stockton to average a little
more than 0.8 foot to the mile. As might be expected from such a
low gradient, there is a great deal of swamp land throughout the
distance. Formerly there was annual flooding of this low area during
the wet season, with a good deal of deposit of silt and stirring up of
organic matter, much of which came from the death of plants and
animals in the preceding dry season. The definite limitation and
constant alternation of dry and wet seasons, together with the prox-
imity of the mountains, must have had a very marked influence on
plankton production in the low lands under such conditions.

OPPORTUNITIES FOR PLANKTON DEVELOPMENT

Recently more and more of these low lands have been reclaimed
and protected by levees. The run-off is thus materially hastened in
flood season and there is much less opportunity for plankton devel-
opment than Kofoid has found for the Illinois River. There is also the
further consideration that most cases in which impounding of the
water occurs, show rapid evaporation after river subsidence, with
great destruction of organisms before they have opportunity to get
into the river channel. Unfortunately, definite information as to
areas still open and details of their seasonal history are not available.

12 University of California Publications in Zoology (Vou. 22

At any rate, it seems that one explanation of the apparent numerical
deficiency in plankton production as compared with the Illinois may
be that there is less impounded water ready to develop and discharge
plankton, and that there are no frequently oceurring minor floods to
wash out these areas. It should be stated, however, that 1913 was an un-
usually dry year; hence the flood conditions were not typical for this
region.
Errect oF THE MOUNTAINS

The mountains probably have just as much influence on plankton
in the river as does the character of the bottom lands. The Coast
Range has no very extensive influence. In the main it is rather
against plankton production. The slopes are steep and the run-off
torrential during the heavy rains. There are not many natural reser-
voirs such as either swamps or lakes, and the surface water is soon
lost. Consequently very little plankton is contributed to the San
Joaquin from these western tributaries. In fact most of them are
dry through a large part of the year and the water they contribute in
time of flood is so full of silt as to hamper rather than hinder plank-
ton production in the main river.

TEMPERATURE

The Sierra Nevada seems to affect production in two rather im-
portant ways. First, temperature in their run-off is rather low for
either quantity or variety of plankton in the higher areas during most
of the year. On the other hand, there are few places for impound-
ing the water in the lower areas and the streams move too rapidly for
much development even on the comparatively low gradients of the
foothills, Hence there is no very great contribution of plankton from
any tributary. Second, the snows, glaciers, forests, lakes and swamps
of the higher region all together constitute an enormous series of res-
ervoirs which hold much of the water in check, not only greatly pro-
longing the flood season, but giving a remarkably even distribution of
flood water over a period of weeks or even months. The effect of this
is evidently twofold, Imasmuch as the volume of water hastens the
flow of the river and so may retard production, while at the same
time it keeps many of the sloughs and swamps sufficiently filled to
maintain a rapid plankton output. This period of flood from the
Sierra often overlaps the period of floods in the valley due to the
winter rains. In other eases it follows or is continuous with the same.
Hence there are a few rises and subsidenees of the floods, almost every
year, some of which are effective in clearing out the sloughs and giving

1920] Allen: Plankton of the San Joaquin River 13

basis for a new plankton crop. The combined flood periods usually
extend from late December to about July, after which there is grad-
ual subsidence to the low-water conditions of sluggish flow and par-
tial stagnation. It should be said that the term ‘‘flood’’ is here
used to include all stages of water at Stockton which are high enough
to keep a distinet current in the river.

The mean annual temperature of the valley, stated as 15.5° C,
does not give a very good idea of the real conditions at Stockton. For
one thing, the range in temperature in every twenty-four hours is
considerable throughout the year. The nights are almost invariably
cool even in late summer and by far the larger number of days
become quite warm. The average range for the year is about 8° C and
is about 8° C in winter and 12°C in summer. On the other hand,
the seasonal range is not so very great. Very rarely a high tempera-
ture near 40° C is reached in summer and a low temperature of about
—10° C in winter. On the whole, there is good reason for thinking
that temperature fluctuations in the San Joaquin River Basin have
less influence than some other conditions on the general plankton
production.

LicHtT

Of course the fluctuations in available light are of great import-
ance. These fluctuations are dependent on a number of conditions,
such as the seasonal changes in length of days, turbidity of the water,
cloudiness, and agitation by wind. All these influences are most ad-
verse during the winter months, coincident with adverse temperature,
so that it is almost impossible to prove which is most responsible for
searcity of plankton at that time.

As already stated, the turbidity of the waters in the Stockton region
is very great and fairly constant. During the greater part of the first
six months of the year this is evidently due mainly to very fine silt.
During the rest of the year the high organic content seems to have
some influence. Although the net with its brass parts was a rather
conspicuous object in clear water, it was never visible one meter be-
low the surface at any station. There are, however, no data available
for accurate determination or comparison of turbidity.

AtrR CURRENTS

Since Stockton is in a low region adjacent to extensive swamp areas
and waterways, it is considerably affected by fog and clouds. The
exclusion of light from this cause is quite important in the course of

14 University of California Publications in Zoology (Vou. 22

the year. Being located almost opposite the Golden Gate, this region
is also under almost daily influence of distinct air currents. These are
very frequently strong enough to make the water surface quite rough
and there is scarcely a day that it is not made ripply for some hours.
This also causes important loss of light throughout the year.

’CHEemIcAL ConpiTIons Not STupDIED

No definite data are available as to the chemical composition of
San Joaquin waters. Hence discussion of this important factor must
be deferred.

TIME

The ocean tide is very much in evidence at Stockton, but the avail-
able data are not adapted to satisfactory study. The extreme range
is about three feet, but that does not oceur very often. The only local
records were those from a private tide-guage kept by Dixon Brothers
Transportation Company. These records were made very irregularly
in connection with the movement of their barges and cannot be used
with much confidence in this discussion.

AQuatic AND MARGINAL VEGETATION

No definite study has been made of the aquatic and marginal vege-
tation of this section. The ocasional dredging of all larger water-
ways has kept down such growths in the places most accessible locally.
Hence the following list must be regarded as incomplete. It is cer-
tainly inadequate so far as the typical delta flora is concerned.

Chara sp. oceurs abundantly in some of the ditches and narrow
waterways. It has not been observed in the river or in the larger
canals, possibly because of the dredging. Where found it furnishes
extensive lodging places for myriads of microscopic animals and
plants.

Duckweeds, probably Lemna gibba L. and Lemna minor L., are
very conspicuous in the fall in quiet nooks and ditches.

Typha latifolia lu. is very abundant in a few places and is fre-
quently found in small groups along any water margins.

Alisma plantago L. is said to be common.

Sagittaria is common and three species at least occur in this region.
Apparently S. latifolia Willd is most frequent, though S. greggu J. G.
Smith, and SY. sanfordii Greene are more characteristic of the locality.

Urtica holosericea Nutt. is very abundant on most undisturbed
levees and water margins.

1920] Allen: Plankton of the San Joaquin River 15

Jussiaca californica fills some quiet sloughs and canals with an al-
most impenetrable mass of stems.

Scirpus lacustris L., is by far the most conspicuous plant in the
marshes and shallow waters from one end of the valley to the other.

Carex marcida Boott. covers large areas of ground where the soil
remains saturated though not completely submerged through most of
the year.

Anemopsis californica Hook. occurs in temporary marshes and is
peculiar to the rainy season.

The most abundant willows are Salix nigra Marsh., S. lasiolepis
Benth., and 8. fluviatilis Nutt. Although abundant by natural propa-
gation, they are frequently planted along the levees to help to hold the
dirt in place.

Populus fremonti Wats. is common along the water courses, but
not abundant.

Ruwimex salicifolius Wats. is conspicuous in marshy ground, espec-
ially in the heavy loam and peat soils. R. occidentalis Wats. and R.
Crispus are also prominent.

Polygonum amphibium L. occurs in the ditches and narrow water-
ways. So far as observed, it furnishes remarkably good shelter for
minute animals and plants.

Ranunculus aquatilis L. is exceedingly abundant in small areas at
times, forming dense mats in shallow water.

Nasturtium officinalis is reported as common, but it has not been
observed by the present writer.

THE COLLECTING STATIONS

Three collecting stations were used. Plate 20 Station I was located
in Stockton Channel at the foot of Yosemite street. This is about one
mile and three-quarters from the river; four hundred yards from
Mormon Channel outlet and three-fourths of a mile from the steamer
landing at the head of Stockton Channel. There was a good deal of
sewage coming down this channel. Mormon Channel was an open
cesspool during most of the year. Hence this station seemed to be
fairly typical for the study of organisms in dilute sewage.

Station II was in the river, from four hundred to eight hundred
yards above Stockton Channel, and it represented as nearly natural
river conditions as could be found in this section.

Station III was in Smith Canal about four hundred yards from
the river. There was a small amount of sewage coming down this

16 University of California Publications in Zoology [Vow 22

canal from the outskirts of the city. There was also a small slough
about one hundred yards from the place of collecting. The general
similarity to river conditions was well marked.

Station IV was not used in this series.

Stockton Channel and Smith Canal are more subject to disturb-
ance by prevailing winds than is the river. Smith Canal being shal-
lowest, Station III was probably most affected.

Stockton Channel was vastly more disturbed by river traffie than
either of the other stations. Smith Canal was rarely affected in this
way. Station II, in the river, was probably not stirred up one-tenth
as much as Station I.

The turbidity of the water was least at Station III during 1913,
and greatest at Station II. But Station III was never clear and the
turbidity was not much less than at Station I.

Since the times of taking the temperatures at the various stations
varied by an hour or more, an aceurate comparison is impossible. The
observer, however, always expected to find the highest temperatures
at Station I, and the lowest at Station II and something between these
at Station ITI.

There was no vegetation of consequence near Station I, but the
levees were heavily covered at both the others. No aquatie vegetation
occurs at any of the stations.

River CuRRENTS AND DepTus

Tidal currents were sometimes very noticeable at all the stations,
but strong currents of any sort were very rare except at Station IT,
where they were noticeable for several months during the spring and
early summer. The highest estimate placed on the rate of the river
current in 1913 was four miles per hour. River transportation men,
notably Captain Curry of the Island Transportation Company, say
that five miles per hour is often reached during the heavier floods.

The least depth of water noted at the stations at low tide was about
one and one-half meters at Station I, two and one-half meters at Sta-
tion II and one meter at Station III.

COMPARISON OF STATIONS

The general form of the three channels is somewhat different. The
bed in all cases seems to be a clay with variable superimposed ooze.
Stoekton Channel is a straight eanal ending blindly at the steamer
landing, two and one-fourth miles from the river. It is nearly the
same width throughout, probably two hundred feet on the average.

ug

Plankton of the San Joaquin River

Allen:

1920]

MAP OF STOCKTON CHANNEL AND ENVIRONS.
Reduced from U.S. War Department
Maps in House Document number 1/24.

By
James and Wesley Allen.

Scale one mile.

Fig. A

18 University of California Publications in Zoology (Vou. 22

Its flow is westward. Mormon Channel empties into it about half way
up on the south side. Miner Channel, after traversing the city as an
open ditch, empties into it through MeLeod’s Lake about three hun-
dred yards from the steamer landing. McLeod’s Lake is merely a
broad slough some four hundred yards in length. It was almost
filled with arks and boat houses during 1913. All sorts of rubbish
and refuse were dumped into Miner Channel and McLeod’s Lake at
that time, including some sewage from factory drains and some refuse
from the tannery.

The river channel is very crooked. The general direction is north-
east for about one mile above Station II. At Station II it is nearly
east, but within another half mile it has turned to the west. The width
is kept fairly uniform by dredging and it probably averages one hun-
dred and twenty feet near the station.

Smith Canal is a straight channel about sixty feet wide and two
miles long, ending abruptly at the northwest city limits. An open
ditch across the northern edge of the city carried waste water from
certain gas wells and some sewage directly into its upper end, during
most of 1913. This ditch was also partly filled with rubbish and
garbage.

METHODS OF SECURING DATA
Time OF COLLECTING

Most of the collections at Stations II and III were taken at seyen-
day intervals, at week ends. There was occasional variation of a day
or two. Collections at Station I were made twice a week. The mid-
week collection was usually on Wednesday. In a few cases there was
a change of a day or two in the interval, but there was no failure to
make two collections in any week.

One series of daily collections was taken in Stockton Channel for
one month in July and August. Another series of hourly collections
was taken for twelve hours in Smith Canal about one mile from the
river. The plankton content was slightly different from that of the
regular station in Smith Canal, but this was not realized at the time
the series was being taken. The difference is not great enough to
prevent instructive comparison.

The time of day at which collections were taken was very variable.
Most of the midweek collections were taken after school in the late
afternoon. Most of the week end collections at all stations were taken
in the forenoon.

1920] Allen: Plankton of the San Joaquin River 19

THe Form or Net

The first few collections in January were obtained with a tem-
porary net made of used mill silk. But a net, of number 25 new bolt-
ing silk, was put into use on January 15, 1913, and was used con-
tinuously to January 1, 1915. There were oceasional changes of drain
cups.

The net was constructed after a plan suggested by Professor C. A.
Kofoid. Outspread, its general form is that of a very broad and
short truncated cone, the base having a total circumference of 166.65
centimeters and the apex 17.59 centimeters. The slant length is 60 cen-
timeters. In order to avoid the awkwardness of such a shape, eight
equal folds are made lengthwise and their upper edges closed. The
inner points of the folds are then fastened directly to a brass ring of
proper size. The outer points of the folds and an unfolded part be-
tween each two is bound by butecher’s linen to a slightly conical brass
plate with an opening in the middle which will pass just 10,000 eubie
centimeters of water for each meter hauled, 1.e., 100 square centimeters
area. The convex surface of this subconical plate is kept outermost,
so that in hauling the water may all pass away from the opening,
except that which is in the column immediately before it.

A small brass cylinder is fitted into the small end of the net and
fastened there by butcher’s lmen. Smooth grooves on the outer sur-
face of the cylinder, near each end, serve for securing it to the net as
well as for attaching the drain cup to the distal end.

This drain cup is made of the same silk as the net. It is a very
simple pocket, about 5 centimeters deep, made of two semicircular
pieces sewed together by the circular edges. The straight edges thus
form the top of the cup, just large enough to slip over the end of the
brass cylinder. The size was not kept quite uniform but the filtering
surface of this cup averaged about 100 square centimeters in 1913.
A draw string of white tape is run around the margin of the cup and
fastened by a small hook and eye, such as is used by dressmakers.
The draw string makes it possible to slip the cup over the eylinder end
without tearing. The hook and eye, when properly adjusted, makes a
very secure fastening, easily and quickly opened or closed.

The total net surface before shrinkage was 5,527.20 square centi-
meters, not including the drain cup. The total filtration opening as
ealeulated from micrometer measurements was 690.9 square centi-
meters. This gives a filtration outlet somewhat more than six times

20 University of California Publications in Zoology (Vou. 22

the area of the inlet to the net. Before using, the net was placed in
warm, soapy water and gently rinsed in order to induce uniform
shrinkage.

The drain cup was removed after each haul and the contents washed
off into a small pail. Some organisms clung very tenaciously to the
net and vessels. This was especially true of the stentors and some
rotifers. The water in the pail was strained through a silk eup at
the end of the collection.

Tur Amount oF Haun

The standard collection covered an aggregate haul of twenty-five
meters. Sometimes it was not possible to make a full collection. Ona
few occasions the light was too poor to make a full midweek collection.
At these times it was usually possible to take half the usual haul. On
still fewer occasions the silt clogged the net so badly in the river that
only about one-fifth of a standard collection was taken. Even so it
seemed that the net would surely break before it drained. Drainage
of the net was always hastened by shaking the net slightly or by
working it with the fingers.

Most hauls at Station I were at the depth of three meters; at Station
II, four meters, and at Station III, two meters. Sometimes five meters
could be taken at Station II. On the other hand there were times
when only one meter could be taken at Station III. Most hauls in the
river were taken while drifting. Most hauls in Stockton Channel and
Smith Canal were taken while at anchor. Except on one occasion all
hauls were made by the same person. The net was always hauled as
nearly as possible at such a speed that it would just fail to throw water
from its mouth as it broke the surface. This was about one-half meter
per second. All hauls were as nearly vertical as possible. No par-
ticular effort was made to get in midstream at any time. In fact some
collections were taken near the bank because of deeper water there.
A few collections were taken from boat landings when the writer’s
motor boat was not in working order.

ReEcORDS

Records were kept of the temperature of air and water at each
station. The air temperature was taken first and it was always taken
in the shade without much motion. The water temperature was taken
by holding the bulb from one to three inches below the surface of the

1920] Allen: Plankton of the San Joaquin River 21

water and reading while in that position. Temperature was forgotten
once during the year and on a few occasions it was taken at some
distance from the point of collection. This was usually when there
was a high wind that made any appreciable variation improbable.

The condition of the tide was recorded when it could be detected.
Dixon Brothers’ Tide Record is of some value for comparison, but it is
so fragmentary that it cannot be depended upon. Corrections for this
locality from the United States Tide Tables are of some value.

Records were kept of cloudiness, rain, fog, wind, roughness of the
water, etc., at the time collections were being taken.

The hour and minute of collection was regularly recorded, usually
at beginning and end.

PRESERVATION OF MATERIALS

The collections were preserved in formalin in four-ounce, cork-
stoppered bottles of the so-called vaselinetype. The formalin was not
measured accurately, but it was intended to be from 6 to 10 per cent.
The stronger solutions were used for the heavier collections. The
formalin for one collection was forgotten until two days after it was
taken, but so far as known that is the only serious error. The total
number of collections during 1913 is 242. The year 1913 was very dry
with very little flood water at any station. On the contrary, the
water was unusually low much of the time. For this reason it would
not show the local plankton range and distribution most typically.
But there were some features strikingly similar to river conditions in
other parts of the world, and it will make a good basis of comparison
with 1914 which was a wet year.

TESTS OF SALINITY

In spite of the low water it is not at all probable that sea water
ever had any influence here except in causing tides. Surface samples
of San Joaquin River water were taken at Station II at about the
twentieth of each month. These samples were titrated for chlorine
content by the scientific staff of the U. S. S. ‘‘Albatross’’ and their
report is presented herewith. It is given in parts of chlorine per 1000.

elaine O erase eens 0.0280 UD fl A a ee eee eee 0.0800
Heb a iO wees eee 0.0745 DENT A eee 0.0964
WIEN 25 PAS) ee oe eee 0.1025 Sept 2/lteeeen ees 0.1764
Apr. 26... --- 0.1689 OC tame 19 eens renee ese 0.2352
II foe eee ee 0.0032 IN(OWei 2 ieee eee 0.6600

Ue eae 0.0072 Decl 20\ =a ee 0.1404

22 University of California Publications in Zoology (Vou. 22

The most probable explanation of the variation shown is that the
incoming tide carried some of the polluted Stockton Channel water up
stream when the natural stream flow was very weak. No other tests
of the chemical composition of water at any station are available.

MEASUREMENT OF VOLUME

In order to measure the mass of material secured in the collections,
a Bausch and Lomb hand centrifuge was used. The sedimentation
tubes were graduated to tenths of a eubie centimeter. This machine
makes 23 revolutions to each turn of the crank. After a few trials
it was decided to run at 54 turns per minute. While no amount
of practice made uniform speed possible, the average was kept at
about 1300 revolutions per minute. The time of running was four
minutes. Experience indicated that this was a little longer time than
necessary, but it was undertaken with the intention of compensating
for any possible inaccuracy due to variation in rate. Since this indi-
cated only the mass of material held by the net, it was necessary to
make some supplementary test to determine as nearly as possible what
volume went through. Only two or three such tests were made because
of the pressure of other duties, but the indication from filter paper
tests is that the net sometimes retains only one-tenth of the mass of
material actually present in the water. This material is often com-
posed principally of silt.

THe ENUMERATION

After considerable experiment, the count of the organisms in the
catches was begun in September, 1914. Since the time available was
nearly always at night, almost all the counting was done by artificial
light from an ordinary 60-watt, frosted, Incandescent globe. Only
rarely was it possible to make two counts in one day. Hence the enum-
eration was not finished until the night of June 18, 1915.

APPARATUS

The microscope used throughout was a Spencer with 16 millimeter
objective and 8x ocular. It was equipped with a quick screw sub-
stage and a Spencer mechanical stage. The Whipple ocular micro-
meter and the Rafter counting cell were used. Its largest square cov-
ered 1.1 square millimeters with the above lens equipment, so that the
labor of calculating was slightly increased by the fractional area.

1920] Allen: Plankton of the San Joaquin River 23

PROCEDURE

STANDARD CONCENTRATION

In preparation for counting, all catches were first brought to a
volume of 100 cubic centimeters by addition of water or, in a few
cases, by decanting some fluid. If the concentration was too great at
this volume, dilution was made to 400 or 800 or 1,600 eubie centimeters.
No other quantities were used because the inerease in difficulty of com-
putation would offset the difficulty in counting. This was due to the
fact that the above quantities were used often enough to make the for-
mation of computing tables useful for them.

MeruHop or Fitting Sep@wicK-RarrerR CELL

In the process of filling the cell after thorough mixing a little more
than 1 cubie centimeter was taken quickly into a pipette. The cell was
then filled as rapidly as possible until the cover shpped into place. This
never occurred completely until there was a slight excess of fluid. The
excess was immediately taken back into the pipette, leaving the cover
glass flat. The possibility of some error is evident, but experiment in-
dieated that this method gave more even distribution in the cell than
any other and that errors were not appreciably more frequent than
those attending other methods. The method was followed throughout
the whole series and every detail was handled by the writer, so that
there must have been practical uniformity. This would certainly re-
duce the significance of any error which may have been incident to the
method.

MAKING AND RECORDING THE COUNT

After filling the cell satisfactorily, a rapid survey was always taken
in order to estimate the relative amounts of plankton and non-
plankton. The estimate was then recorded in percentage of silt. With
these preliminaries completed, the work of counting was begun, fifty
fields being always counted. This made a total of 60.5 eubie mill-
meters. Counting was begun on the proximal side of the slide at
point 32 on the lateral scale of the mechanical stage. The field next to
the wall of the cell was not counted, but the next five were taken con-
secutively. This process was repeated at point 16, then at point 80
on the proximodistal scale at the right end of the cell, followed by
point. 87. Points 16 and 32 distal, 87 and 80 left, were then taken in
order. The detail count was completed by ten fields from point 15 to

24 University of California Publications in Zoology (Vou. 22

27 in the median line of the cell. The whole count was completed by
running over exactly half of the cell looking for strays and for a check
on larger organisms which might be irregular in distribution. After
a year’s experience the writer is inclined to think that twenty-five or
thirty fields would be sufficient for the detailed count in view of the
half-slide check. At any rate he is satisfied that the possibility of
error in counting will rest elsewhere than on the method of selecting
areas for counting. It might be said too, that the year’s experience
indicates that the method of filling the cell gives as uniform distribu-
tion of plankton in the cell as can be hoped for in any ease.

The method of recording the count was almost uniform. Mrs.
Allen sat near the microscope and wrote down names or made check
marks as the names were called. In two or three cases about half the
catch was recorded by the writer while himself counting. On about
ten oceasions he reeorded as much as ten fields in ike manner. These
were the only exceptions. Occasionally the writer called the name of
one planktont when another was intended, the mistake being noticed
because it did not sound right. It is altogether probable that some
such mistakes were made which were not noticed. In addition to this,
of course, we must recognize the presence of clerical errors not humanly
avoidable in such a mass of material. It can only be said that all
reasonable precaution has been taken to avoid them.

COMPUTATION AND TABULATION

After recording, the counts were computed for a full eubie meter,
and then tabulated by key sheets, such as suggested by Professor
Kofoid in his Illinois report. From these sheets they were finally
transferred to the statistical tables.

IDENTIFICATION OF FORMS

Identification of species, or even genera, was very difficult in
many cases. This was due to several conditions. First, the preserved
planktont was often very different in appearance from the living speci-
men. Second, many kinds had very marked tendeney to coherence
or agglutination in formaldehyde. Third, many of the smaller organ-
isms were hidden wholly or in part by silt or by larger organisms.
Fourth, many different organisms have the same appearance in very
young stages; they also resemble mature stages of simpler forms.
Fifth, distinctive characters were frequently invisible in the position
found in the Rafter cell. Sixth, many forms were not sufficiently

1920] Allen: Plankton of the San Joaquin River 25

figured and described in the literature immediately available for use.
Seventh, much of the accurate identification of plankton forms would
require long time and careful work, even for specialists in the various
groups. The writer was hampered by lack of time and experience
in identification in all groups. Eighth, the synonymy is confusing.
This, however, is rather an aggravation than a difficulty in the
sense of the foregoing.

This list certainly seems imposing as stated. As against it, the
following facts should be noted. First, that more than one year was
spent in studying the living materials, with both 16 millimeter and 4
millimeter objectives, before there was any attempt to count. In
this way, sufficient familiarity was obtaimed with many forms to
enable identification even in much contracted, distorted and broken
conditions. Second, that most of the names as finally applied meant
something definite to the writer, even though there might be error in
their specific application. While this fact is unfortunate for the
specialist who may wish to know exactly what species are present,
it surely leaves the possibility of drawing some valuable conclusions
as to seasonal changes, plankton rhythms, and relative numbers.
Third, there were enough prominent planktonts, easy to identify, to
make a good foundation for a report on plankton characteristics of
this region at such stations as were selected. Fourth, those plank-
tonts hardest to identify were mostly of the kind which would be
largely lost through the meshes of the net, or which were adventitious
and so of minor importance in solution of the greater problems of
plankton production and distribution. Fifth, the various totals are
not much affected by specific errors of identification.

ESTIMATION OF SILT

In estimating the percentage of silt, the same possibility of error
was noticed as that mentioned by Kofoid (1908), i.e., some of the
material, being flocculent in character, would appear unduly prom-
inent in the Rafter cell; whereas, the compression of the centrifuge
would make it relatively small in the volumetric record. While it
seems probable that differences in the stations and in seasonal condi-
_tions give this error some real importance, there appears to be no way
of avoiding it. There may be some compensation in the fact, that
with larger quantities of sediment there is usually a larger propor-
tion of heavy materials, thus making the compressible materials less
conspicuous.

26 University of California Publications in Zoology (Vou. 22

THE CLOGGING OF THE NET

The clogging of the net is undoubtedly an important factor affect-
ing the catch and it was also quite variable under 1913 conditions
here. Hence some designation of its probable condition is very desira-
ble. In spite of this it was finally decided to ignore it for 1913 at
least. This is because too few filter paper, or other supplementary,
catches have been made to give adequate ground for estimation.

VOLUMETRIC DATA

There is not a great deal to say on this topie as yet. The main
points are distinetly shown by plate 1 and table 6. The two most
interesting points, in the light of such investigations elsewhere, are
that only Station I shows a very distinct vernal pulse and that the
autumnal pulses are most prominent at all stations. This statement
needs some qualification since there was a higher maximum shown at
Station I in March than in the fall. This vernal pulse was, however,
so very abruptly developed, and the autumnal so very gradually, that
it seems natural to assign the greater importance to the latter. At
neither of the other stations does the vernal pulse compare in magni-
tude with the autumnal. Indeed, at Station III, there is no well
marked, vernal pulse.

It is worthy of note that volumes appear least variable at Station
I and most so at Station II. It might, at first thought, seem that
this was owing to the uniformity of food supply at Station I, caused
by the constant inflow of sewage throughout the year. Closer exami-
nation of the records suggests, however, that variation in speed of
currents in the river, together with the dilution due to flood waters
is more potent. This estimate of the importance of the current as a
factor is supported by collections made in the San Joaquin River
near Fresno, California, in August, 1916. Although this was the
season for maximum occurrence of plankton at Stockton, not enough
was taken by the net at Fresno to be measurable volumetrically with
any accuracy. Since the current at Fresno is about as rapid in the
dry season as at Stockton in flood season, it seems certain that it has
a profound influence. Still the importance of the uniform food sup-
ply at Station I must not be minimized.

1920] Allen: Plankton of the San Joaquin River 27

The whole series of collections for 1913 is now (1916) in the per-
manent possession of the Department of Zoology of the University of
California.

ORGANISMS FOUND IN SAN JOAQUIN PLANKTON
DEFINITIONS

Professor Kofoid’s definitions are followed as closely as possible,
although only a few terms will be used. This report designates only
three types of planktons, i.e., the continuous, the periodie and the
adventitious. No closer distinction is advisable in view of the writer’s
lack of definite knowledge of life histories of various species. There
has been no difficulty about the application of the general term
‘plankton’
things found in these collections, because there was no case observed
in which the plant or animal seemed distinetly out of place. It might
be rare, and perhaps evidently ill-fittmg, but in no way could its
presence be regarded as surprising. Hence it becomes perfectly
natural to apply the term collectively to all the organisms found.

,

to the typically mixed population of minute living

CoMPONENT F'orMS

A total of 471 planktonts was listed during the year, though only
396 were recorded from the preserved material. The number of
species present was doubtless much greater. Those not recorded were
found only in the living material and in small numbers. Of those
recorded, some forms which might be distinct species were placed
together in one because they could not be distinguished during the
count. This lack of distinction was sometimes due to the inadequate
preservation or to the rarity or to the difficulty of identifying specific
characters while counting. Others were placed together because
the writer’s acquaintance with them was not sufficient for definite
recognition. Very many were simply referred to the genus without
attempt at species segregation because identification was too difficult
to be undertaken in the time available. The question of probability
of proper identification will be taken up in the detailed discussion
of each form.

28 University of California Publications in Zoology (Vou. 22

THE PRINCIPAL TYPES OF FRESH WATER PLANKTON

Among the 396 forms recorded and counted in the preserved
material, 201 were thought to be positively identified as to genus, of
which number 107 were also satisfactory as to species. The generic
designation of most of the remaining 195 forms was regarded as
probably correct though some were merely referred to the nearest pos-
sible genus or species according to the information at hand. The
following table gives the general distribution of these forms among
the three stations.

At three At two At one

stations stations station
i BAU SPB 0 een ra ee een eeetomen 90 29 53
IPROGOZ 08, excess eee eee 56 26 37
TROtfer a elecncctepess cece ee 44 11 26
i Crustacea) S22 t owes snc ceetee eee 8 2 2
Miscellaneous! =-se ster tes 3 1 8
Totally see ee 201 69 126

As might be expected of those found at only two stations most are
from stations I and II. Those found at only one station are of the
rarer, less conspicuous kinds.

This table shows the main characteristics mentioned by Kofoid
(1908) as distinguishing fresh water from marine plankton. It may
be well to enumerate his main points as verified in the present study.
The plankton consists of eryptogams and invertebrates, with some or-
ders missing and the others very variable in numbers of representa-
tives. Larval forms are very few and the number of invertebrate
groups much less than that of the sea. The small size of organisms in
fresh water is also a conspicuous feature. There are no large crus-
taceans, no coelenterates, no mature mollusks, few worms, no tuni-
cates or radiolarians, to make diversity such as that of the sea. In
spite of the smaller size of the organisms in fresh water their total
mass is much greater than that in the sea. The highest amount recorded
here is 18 cubie centimeters per cubic meter; the smallest 0.28 cubie
centimeters per cubic meter; while a typical marine product is stated
as 0.12 to 0.48 eubie centimeter per cubic meter. The San Joaquin
production noted was taken from net hauls only, the maximum from
Stockton Channel, the minimum from Smith Canal. Filter paper
catches show ten times the recorded volume in some eases.

1920] Allen: Plankton of the San Joaquin River 29

Masor Groups 0F PLANKTON

ALGAE

No plants higher than the algae have been found in these collee-
tions. Very few bacteriaceae were found because of their small size.
Very few schizophyceae were conspicuous in 1913, though the num-
bers of individuals were sometimes large and the total quantity suf-
ficient in late summer to give characteristic color to the waters. Bacil-
lariaceae were always present and usually in large numbers. Many
of them are doubtless adventitious. Chlorophyeeae were not prom-
inent, though some were present throughout the year. The conju-
gatae were not represented by many species and the numbers were
few.

ZOOPLANKTON

Almost all the zooplanktonts found were included in the three
groups Protozoa, Rotifera and Entomostraca. Other types of ani-
mals are decidedly rare.

Amongst the Protozoa, Ciliata and Mastigophora predominate.
The group Mastigophora is meant to include the same organisms as
comprised under that head by Kofoid (1908), i.e., ‘‘all green and
brown flagellates, sometimes classified with the Chlorophyceae and
Phaeophyceae.’’ Rhizopoda were usually present but in small num-
bers. Heliozoa were rare except for one or two smaller forms which
kept up rather large totals for the group. Suctoria were rare. No
Sporozoa were recognized. Ciliata were distinetly more noticeable in
the dilute sewage of Stockton Channel than at either of the other
stations.

The Rotifera were even more prominent inhabitants of Stockton
Channel than the ciliate Protozoa, but their numerical superiority
may have been due to larger size and consequent capture by the net.
The numerical difference at the other stations was not very marked.
There is no question that their considerable size and large numbers
entitle them to the leading place among analytic organisms assigned
by Kofoid (1908) to the Illinois Rotifera. The greater abundance in
the sewage laden water is, however, rather against his suggestion
that they may be found to be more characteristic of river than of
lake plankton. Local conditions indicate sewage or at least organic

30 University of California Publications in Zoology (Vou. 22

content as being a deciding factor. Apparently, most of the species
recorded here are to be regarded as normal constituents of the local
plankton.

With the exception of three or four specimens of Gammarus
found on two different dates, and of a few miscellaneous forms, the
Entomostraca are far the largest of the local planktonts. While much
less numerous on the whole than they were in the Illinois River, they
undoubtedly play a large part in the life of our waters. Copepoda,
through larval forms, are distinctly in the ascendant, with Clado-
cera somewhat scattering and Ostracoda barely represented. Most of
the forms found appear to be true planktonts. In fact, Cypris, the
sole member of the Ostracoda, is the only genus which is evidently
adventitious.

Turbellaria, Oligochaeta, Hexapoda, Hydrachnida, Gastrotricha
and Bryozoa barely find representation at any station. Their influ-
ence in the plankton is negligible.

TOTALS OF MAJOR GROUPS

The following table of averages (text table I) will serve to indi-
cate In some measure the proportionate representation in the San
Joaquin plankton of the most typical constituent groups. As already
noted elsewhere, 1913, was a comparatively dry year so that the
production in most cases was probably below normal. The figures
given are the result of the count of individuals, except in the ease of
colonial forms such as Bacillaria, Synura and Scenedesmus where the
colonies only were counted. The small numbers as compared with
Kofoid’s similar table (1908) for the Illinois plankton of 1898 is
mainly due to the fact that all San Joaquin enumerations are from
silk net collections, whereas many of his were from filter paper
catches. Our table includes all recorded forms whether satisfactorily
identified or not. It should be noted that in the total of synthetic
organisms Schizophyceae are included because they do some of that
work. All of the Mastigophora are also included because there was
not sufficient acquaintance with them to distinguish synthetic and
analytic forms and it was understood that most of them found here
were synthetic. The averages are computed on the basis of 104
eatches for Station I, 52 for Station II and 51 for Station III. The
daily and hourly series are not included in the general discussion
except as incidentally referred to. They require separate discussion.

1920] Allen:

Plankton of the San Joaquin River

Text Tasie 1.—Torau PLANKTONTS BY Masor Groups

Total Phytoplanktonts.
Bacteriaceae..............
Schizophyceae..........
Chlorophyceae........ ;
Bacillariaceae............
Conjugatae................

Total Zodplanktonts .....
Mastigophora...........
Rhizopoda.......
Heliozoa...
Ciliata.......
Suctoria...
Total Protozoa...
TRANCE ccorenpennnceso
Bdelloida........... ;
loins
Total Rotifera..
Cladocera.........
Copepoda......
Total Entomostraca
Miscellaneous...

Total planktonts

enumerated

IS yielts) OVEN OG acer eoneceeeeeceeoceeece

Nmrallivtlcwe noe ees

Total Ebytoplanktonts:
Bacteriaceae...
Schizophyceae... 5
Chlorophyceae..........
Bacillariaceae
Conjugatae... 5c

Total Zooplanktonts Sree
Mastigophora........
bizopodae.s.c2---.--

HeliozOa nse ne ;
cue,

Bdelloida.
Ploima...
Total Rotifera...
Cladocera cts...
Copepoda...............+
Malacostraca...
Total Entomostraca
Miscellaneous...
Total Planktonts
enumerated..........
Syantheticte ec...

Number
of
forms

85

Number
of

forms

Station I

Total Average
2,720,856,600 26,162,100
1,696,364 16,310
166,755,148 1,603,414
188,417,098 1,811,722
2,351,342,460 22,609,062
12,651,930 121,653
1,102,116,740 10,597,272
385,691,226 3,708,569
17,402,198 167,328
38,583,488 370,995
98,463,242 946,762
79,296 762
540,219,450 5,194,416
156,992 1,509
36,328,460 349/312
467,115,946 4,491,499
503,601,398 4,842,320
400,992 3,855
57,856,500 556,312
58,257,492 560,167
38,400 369

973,340
857, 862

Hm
rob
Meh
HRS

36,759,372
29,854,420

Number
of
forms

31
Station II

Total Average
2,216,347,628 42,622,068
1,035,072 19,905
67,219,364 1,292,680
77,972,944 1,499,479
2,052,872,514 39,478,317
17,247,734 331,687
229,332,166 4,410,230
136,713,846 2,629,112
7,842,488 150,817
13,376,096 257,232
23,291,268 447/909
467,776 8,995
181,691,474 3,494,065
1,933,424 37,181
2,449,472 47,105
41,559,652 799,224
45,942,548 883,510
384,000 7,384
770,768 14,822
1,154,768 22,206
543,376 10,449

2,445,679,794
2,352,026,402

47,032,298
45,231,275

115, 478 6,904,952 93,653,392 1,801,023
Text Taste 1.—Torau PLanxtonts By Masor Grourps—Continued
Station IIT Member Daily
ai ca

Total Average forms Total Average
2,090,812,294 40,996,318 53 1,018,801,028 32,864,549
116,992 2,294 1 115,392 3,722
99,840,742 1,957,661 12 80,574,044 2,599,163
91,241,112 1,789,041 11 67,560,712 2,179,378
1,878,169,822 36,826,859 25 869,719,232 28,055,459
21,443,626 420,463 4 831,648 26,827
253,153,822 4,963,800 61 335,441,120 10,820,681
134,216,822 2,631,702 14 57,456,320 1,853,429
14,706,624 288,365 4 3,155,872 101,802
14,003,600 274,580 2 19,193,826 619,156
22,003,692 431,445 6 40,488,334 1,306,075
409,984 8,039 0) ee ; Mee eee
185,340,722 3,634,131 26 120,294,352 3,880,462
1,539,424 SOMISS Gace. ets See ERE
2,897,100 56,806 3 3,745, 752 “120,831
61,996,492 1,215,618 27 165, ‘007, 160 5,322,812
66,433,016 1,302.609 30 168,752,912 5,443,643
469,040 9,197 2 230,400 7,432
742,032 14,549 2 46,141,056 1,488,421
PAD" "ae Neb Re ROTOR ig pcan eed,
1,211,092 23,746 4 46, 37h 456 1 (495, 853
168,992 3,314 1 22,400 723
2,343,966,116 45,960,118 114 1,354,242,148 43,685,230
2,225,029,116 43,628,020 ...... 1,076,257,348 34,717,978
118,937,000 2,382,098 ...... 277,984,800 8,967,252

AS OGIN VUNG -ecrccccaxnteeate ay

32 University of California Publications in Zoology [Vou. 22

Text Taste 1.—Torat PLANKronts By Masor Groups—Concluded

Number Hourly
fons Total Average
Total Phytoplanktonts............ Milas chtecenrenstevbnnantore 61 476,644,270 32,172,832
Bacteria Cede izaccccitse ee ee oe 1 112,192 8,630
Schizophy cede::!iavcc.ssenueeeeee nore ecu: 12 64,886,064 499,123
Chlorophyceae..... sssstieaser Get edearecsececsass ee 10 22,150,470 1,703,883
Bacillariaceae: chicane tes ce 32 377,380,220 29,029,248
Conjugatae........... Jelesventestte 6 12,115,324 931,948
Total Zoéplanktonts a ves iesaae 72 179,588,061 13,814,465
Maiti popbore te.cscsccomntne i eaten eter 15 51,114,592 3,931,892
RNIZOPOU aie. cece nenerteeccsereme eee re ee eee 8 5,160,360 396,950
Helio zantac heres cee et eee 4 5,739,216 441,478
Ciliata..... ee ace 6 40,775,578 3,136,583
Suctoria.......... een, 5 Aes 1 25,600 1,969
Total Protozo 34 102,815,346 7,908,872
Rhizota : 2 33 209,888 16,145
Bdelloida.... Saco sev deb na sus ev Be a SsONG cance ee eT eae 2 2,930,384 225,414
Ploima....... Boe Smee h er sey Ds 29 70,717,563 5,439,813
Total Rotiferd. cc ccc.ccesceers ee ate 34 73,857,835 5,681,372
Cladocera......... atc ; a 2 451,776 34,752
Wopepod ainda eeeesse ee 2 2,463,104 189,469
Motalebntomostracanuecweeee eee 1 2,914,880 224,221
Miscellaneousi.t2.iraccmcsctscetcs gcse eee sane siggeneesacvyonee@ce ees
Total Planktonts enumerated....................... 133 656,232,331 45,987,297
Synthetic.............. A Tye cee ed Opa. 527,758,862 36,104,724
Atrial y Gio cnc asec ok terest rac ee 128,473,469 9,882,573

COMPARISON WITH ILLINOIS FORMS

As in the ease of the Illinois River, this table shows plants to be
more numerous than animals, though they are generally smaller. The
disparity in numbers is slightly different being, in recorded order of
stations 2.5, 9, and 9 to 1, instead of 5 to 1 as in the Illinois River.
The preponderance of Rotifera and Protozoa over Entomostraca is
less marked than in Illinois, being 8.5, 45, and 50 to 1; and 9, 180,
and 151 to 1, respectively. The numbers of Rotifera and Protozoa
are not markedly different from each other in Stockton Channel
though Protozoa are four or five times as numerous as Rotifera at
the other two stations. In Stockton Channel synthetic organisms are
relatively few even among plants proper. In this place the principal
food of the zooplankton, therefore, is probably furnished by the
Bacteriaceae and other saprophytic plants. For this reason the
forms of plankton usually rated as important in more or less direct
support of a fish fauna are few in kinds if not in numbers, although
there is a conspicuous animal population.

At Station I, Copepoda (including immature forms) outnumber
Cladocera about 18 to 1, but only about 2 to 1 at Station II and 1.5
to 1 at Station III. Protozoa are 1210, 500, and 404 to 1 of the
Cladocera, distributed as follows: Rhizopods 45, 22, and 32 to 1,

1920] Allen: Plankton of the San Joaquin River 33

Ciliata 236, 64, and 48 to 1, Mastigophora 927, 361, and 292 to 1.
Cladocera are outnumbered by plants 6540, 6090, and 4555 to 1.
Diatoms are responsible for most of this with 5652, 5640, and 2314
to 1. Schizophyeeae appear at 400, 185, and 217 to 1 and Chloro-
phyceae 452, 214, and 198 to 1.

The most striking features of these results when compared with
those of Kofoid (1908) are two in number. First, there is the re-
markable number of Copepoda in Station I. Second, the astonishingly
small number of synthetic organisms and of Protozoa at all stations,
in proportion to the number of Cladocera. Since Cladocera are almost
all caught in the adult stage and since they are almost all retained by
the silk net, they present very good ground for comparison of plank-
ton catches everywhere. Hence the numbers of Cladocera, the lack
in numbers of other organisms and the results of the few, filter paper
catches point conclusively to the fact that the numerical and volu-
metric study of plankton calls for absolute filtration, high magnifica-
tion and a laborious technique adequately to represent the sources of
food, and the interrelations of the organisms of the plankton.

DETAILED DISCUSSION OF STATISTICS RECORDED BY THE AUTHOR
PREFATORY

Tables and plates have been prepared to show in numerical or
graphic form the various facts of distribution and occurrence which
are or may be reckoned as important. This commentary is intended
to elucidate and amplify such records and to serve especially as a
guide to the details of observation or conclusion concerning which the
writer is certain or uncertain. Averages, when given for each or-
ganism in numbers per cubic meter will be given for each station on
the basis of 104 collections at Station I, 52 at Station II and 51 at
Station III. Averages are only used because there is no other way
of making a general numerical comparison in brief form. Tempera-
tures, in degree Centigrade, are given both for surface water and
for air. While the latter may be unnecessary it was thought that it
might help to give an idea of the conditions locally.

Numbers of planktonts are recorded in units for the same rea-
sons of consistency and convenience as those mentioned by Kofoid
(1908). There is not the slightest intention to imply fictitious accu-
racy by unit expression. Those who prefer can read the record in

?

“‘round numbers.’’ The writer himself rarely gives any thought to

more than the first three figures of a number.

34 University of California Publications in Zoology (Vou. 22

ALGAE

Bacteriaceae

Members of this group were unquestionably abundant both in
numbers and kinds, but they were very rarely retained by the silk
net. In facet, Spirillum undula was the only representative recorded
from Stockton Channel, the station most favorable for Bacteria and
giving most evidence of their presence. The average number there,
16,310, is ridiculously small in view of the general conditions and in
consideration of the filter paper collections which indicated a total
volume of catch about ten times as great as that found in the silk
net catches. The relatively great numbers of Cladocera and Copepoda
also serve to emphasize the fact that the large portion of the plank-
ton population is very freqently beyond the reach of the usual
methods of observation. Silk net methods can never be more than
suggestive of the productivity of the waters since they must deal
mainly with the giants of the plankton. For that reason, an extended
discussion of the Bacteriaceae cannot be undertaken for this series.
It might be said, however, that general conditions indicate a maxi-
mum production of Bacteria in late summer along with the other
groups.

Beggiatoa and Micrococcus were only recorded from Stations II
and III, and then only onee, but they were probably common at all

stations.
Schizophyceae
Station I Station II Station IIT Daily Hourly
Number of forms........-........- 18 15 15 15 df
Average per cubic meter ...... 1,603,414 1,292,680 1,957,661 2,599,163 499,123

This group was most conspicuous at all stations in July, August
and September, when it gave a peculiar color and appearance to the
water, but it had some representation throughout the year. Anabaena,
Nostoc and Oscillatoria were generally most prominent. Some of the
smaller forms were probably represented but not identified. Some
small forms were also probably confused with other groups. The
group, aS a whole, does not seem according to record to be of quite
so great importance as in the Illinois, but this apparent lack is doubt-
less due to escape through the net. The color of the water alone
would suggest that much of the material is lost. It is then, not only
safe to say that the group is valuable in furnishing food for other

1920] Allen: Plankton of the San Joaquin River 35

organisms, but also that it probably holds a high place in working up
the organic content of the water. Identification, even of genera, was
frequently rather difficult in this group, although there was not often
any question as to their belonging to the Schizophyceae. Names as
recorded are to be regarded as suggestive rather than positive.
Eyferth’s Einfachste Lebensformen and Tilden’s Minnesota Algae
were the guides mainly used.

DISCUSSION OF SPECIES

Anabaena SDP Station I Station II Station IIT Daily Hourly
Average 57,600 317,644 437,967 245,139 1,531,949
Not clearly distinguished from Nostoc, straight filaments being the

characteristic usually considered indicative. Includes some Aphani-

zomenon. Found occasionally throughout the year. Abundant only
in July, August and September, at all stations, in a water tempera-
ture ranging from 23.5° C. to 28° C. Largest number recorded at
Station I on July 12, Station II on August 9, and Station III on
July 19.

Aphanocapsa spp.
Station I Station II Station III Daily Hourly
Average 117,381 84,916 74,329 441,469 187,647

Most of the colonies counted under this name probably belong un-
der Clathrocystis and Microcystis. There were probably few, if any
Aphanocapsa present. The characteristics of Aphanocapsa were not
understood until the count had gone too far for revision. Since
Clathrocystis and Microcystis were also more or less subject to con-
fusion it was thought best to let the record for 1913 stand under this

head. The maximum production occurs at about the same time as
that of Microcystis at all stations. Hence the error probably affects
nothing -but the question of species distribution. Clathrocystis does
not appear on the record though now known to be present and it
might be well to transfer the Aphanocapsa count to that heading.
The late summer maximum, occurring in higher temperatures and
the sudden fall in numbers in colder waters suggests the character-
istics of Clathrocystis as noted by Kofoid (1908) in Illinois.

Coelosphaerium kiitzingianum Naeg. Recorded three times from
Station III and once from each of the other stations. Very small
numbers in all eases. Identification not positive.

36 University of California Publications in Zoology (Vou. 22

Gloecocapsa conglomerata Kiitz.

Station I Station II Station III Daily Hourly
AONB IGS (a cesctsachccs akan tema meee 13,685 4,438 11,015 191,027 49,811

Recorded only in July and August at all stations. Identification
not positive. Abundant through daily and hourly series and in con-
siderable numbers for the few times taken in the regular series.
However, not an important factor so far as these catches indicate.
Losses through net probably heavy.

Gloeocapsa spp. y : :
StationI Station II Station IIT Daily Hourly
or ee OR 197,400 141,594 181,426 520,660 539,132
Probably several species are included under this heading. They
are found at all stations throughout the year though most abundant
in July and August. Losses through the net were probably very
heavy and the genus must play an important part in local waters.
Identification considered probable though some confusion affected

the count at times.

Average

Gomphosphaera aponina Kg.

Station I Station II Station III Daily Hourly
ANO@YAPC <2. o2: fecccce-ccsscsiscooesscewe 7,856 8,968 14,485 726 36,620

Identification uncertain. Occurrence at irregular intervals
throughout the year at all stations. Numbers small.

Inactis tinctoria Agardh

Station I Station II Station IIT Daily Hourly
ANVOYAG ON tess se eres er eee 532,790 215,653 594,302 0 105,792

Identification uncertain. None recorded until August. Very few
after October at any station. Numbers large while present. Heavy
loss through net probable. Evidently of considerable importance in
the plankton while present. ;

Merismopedium glaucus Ehrbg.

Station I Station II Station ITI Daily Hourly
AN CLA QO) ce coesce-sncnsceencteeoesetesce 89,512 5,117 6,992 413 210

Identification satisfactory. Losses through net very heavy. Num-
bers fairly large in November and December. Rarely recorded earlier
in year. Small size makes it easy to overlook even when present.

Microcystis sp.

Station I Station II Station III Daily Hourly
Average ......... Spee CERES SSeS 44,240 64,890 43,646 166,545 364,169

Identification satisfactory. Count probably too low on account of
confusion of some colonies with other forms. Found oceasionally

1920] Allen: Plankton of the San Joaquin River 37

thrughout the year at all stations. Much more abundant in July,
August and September. Loss through net certainly very great. An
important member of the plankton, but net catches do not afford a
good basis for discussion of its distribution.

Nostoc spp.

Station I Station II Station III Daily Hourly
BAN ON DO Gy Saco Eee ccc sce ate sete eensnee 156,435 301,283 459,306 547,678 1,794,781

All the plants included under this head were filaments of the
contorted type. The count gives the number of filaments in some
cases though usually fragments of colonies constituted the units.
Whole colonies were rarely, if ever, found. Possibly three or four
species are included in this enumeration. Nostoc appeared occasion-
ally throughout the year and became quite prominent in July, Au-
gust and September. In view of the fragmentary condition of the
colonies it is probable that the loss through the net was considerable.

Oscillatoria formosa Bory.

Station I Station II Station III Daily Hourly
VANICTAQC! Gz c2ccanc2cecccectecwetecsese- 2,037 45,699 2,205

Identification uncertain. This form occurred more often at Sta-
tion II where it was recorded frequently throughout the year, reach-
ing its maximum in June. It does not seem to be very important
since its size makes it improbable that loss through the net was very
great.

Oscillatoria spp. ; : . ;
Station I Station II Station IIT Daily Hourly
PANY OL AGG essen seen estos adeawanee 210,437 32,323 49,941 299,126 105,792

Probably three or four species are included under this heading.
Found oceasionally throughout the year but distinctly a summer
form. Maximum in August. Oscillatoria of all kinds were nearly
always found in single filaments or fragments of filaments. Masses
of filaments were rarely seen. This might be considered as support-
ing Kofoid’s suggestion (1908) that physiological conditions may at
times make Oscillatoria a temporary planktont. On the other hand
it does not furnish very definite proof against the view that this form
is an adventitious planktont, cast adrift by gas bubbles or violent
currents.

Oscillatoria tenuis Agardh.

Station I Station II Station III Daily Hourly
AVeTAge nnn eeeeeeeeeeee 46,340 2,404 3,040 154,363 12,207

Identification uncertain. Not a very prominent form. General
occurrence much the same as for the above mentioned species.

38 University of California Publications in Zoology [Vow. 22

Phormidium spp.
Station I Station II Station III Daily Hourly
JAVOTS EO) cakics-phstets ears ch vsesec dees 121,571 31,248 86,171 BD;590) ©, eee

Probably includes more than one species. Genus uncertain also.
Occurrence occasional through the year. Most abundant at Station

I. Maximum in September. Not a very prominent planktont.

Stigonema sp. : : :
Station I Station II Station IIT Daily Hourly
Average aes hly/ 45,665 8,831

Identification very doubtful. Filaments always fragmentary.
Nothing but vegetative cells seen. Referred to Stigonema partly on
account of occasional lateral arrangement of two cells in the fila-
ment. Never very prominent. Maximum in June at Station II
where it was most often found. Apparently of little importance.
Probably adventitious.

The following forms were recorded but once, at one or more sta-
tions, or else are listed because thought to be present in living

material :
Calothrix sp. Recorded once at Station I.
Clathroeystis aeruginosa Kg.
Cylindrospermum comalum Wood.
Dactylococcopsis rhaphidioides Hausg. Recorded once at Station I.
Gloeocapsa gelatinosa Kiitz.
Lyngbya sp. Recorded once at Stations I and II.
Oncobyrsa rivularis Kutz. Recorded onee at each station.
Rivularia sp. Recorded once at Station I.
Symplocastrum sp. Recorded once at Station IIT.

Chlorophyceae
Station I Station II Station IIT Daily Hourly
Number of forms..............-- 15 14 17 8 8

Ay. numbers per cu. meter 1,811,722 1,499,479 1,789,041 2,179,578 1,703,883

These averages indicate only about one-thirtieth of the number
found by Kofoid (1908) in Illinois. Since, however, the main con-
tribution here was made by Actinastrwm, Coelastrum, Pediasirum
and Scenedesmus it may be readily understood that losses through the
net account for most of the difference. The group was represented
through the entire year, though the numbers were often very fey.
Station I showed the peculiarity of a great increase in numbers in
May and June, a decline in July and August, and another well sus-
tained increase in September, October and November. Stations IT
and III showed only one conspicuous rise in numbers, covering about
four months, from July to October inclusive. The numbers oecur-

1920] Allen: Plankton of the San Joaquin River 39

ring in other months were very small. It is quite difficult to de-
termine the cause of the two pulses at Station I as distinguished from
the other two stations. It could hardly be temperature since that
factor remains too nearly constant during the period involved. The
earlier increase in May might be aseribed to the more quiet water rich
in organie matter, and the continuance through November might be
aided by the sewage. The most probable explanations of the inter-
mediate fall in numbers seems to be that predatory organisms may
have been most prominent at that period or that stagnation of the
sewage laden water hindered growth and multiplication. The possi-
bility of the last named factor being the more important is supported
by the fact that increase comes in September when there begins to
be some relief from stagnation by increase of supply from the moun-
tain streams. This relief was not very great in 1913, however, nor is
it very well marked in any year. The possibility of interference by
other organisms is supported by the fact that the numbers present
“are mainly influenced by the numbers of Scenedesmus, an organism
very likely to be extensively used for food by some of the organisnis
of the zooplankton. Amongst the Ciliata, Vorticella seems most likely
to be responsible while Asplanchna is the most prominent of the
Rotifera. But the Copepoda are still more characteristic of this
period and the summer decline of Scenedesmus may be due mainly
to their activity. Chlorophyceae were never very conspicuous in 1913
and they were outnumbered by diatoms 14 to 1 and by Mastigophora
about 2 to 1. Uneertainty as to the percentages of losses of various
forms through the net makes definite conclusion impossible.

The very interesting question concerning recurrent pulses and
their relation to lunar eyeles, discussed by Kofoid (1908), cannot be
answered any more definitely here. It is clear from these net catches
that .there are recurrent pulses (plates 1-5) at about three to six
weeks intervals but there is nothing which warrants more than an
indorsement of his provisional conclusion that there may be an in-
erease in number of chlorophyll bearing organisms to correspond
with each recurrent increase of hght from the moon. It is alto-
gether probable that this problem cannot be solved until some one is
able to carry a long series of daily catches, carefully timed, and by
more accurate methods than those of the silk net. Whether any filter
method would suffice is hard to say. It was hoped that the daily
series carried for thirty-one days in 1913 would help to solve this
problem but it presented no conclusive evidence. (PI. 6.)

40 University of California Publications in Zoology (Vou. 22

Thirty forms were recorded in the count and it was thought that
several others were recognized in the living material. Certainly there
were more species present. So far as net catches indicate, Pediastrum
was the leader both numerically and volumetrically, at Stations IT
and III. At Station I it was not far different from Scenedesmus in
numbers (coenobia counted) and of course, exceeded it in volume of
catch. Scenedesmus was clearly second in importance, Actinastrum
third and Coclastrum fourth. Crucigenia, Raphidium, Richteriella
and Schroederia were frequently found. In view of the common oe-
currence of Botryococcus in other places its scarcity here needs ex-
planation. Failure to identify seems to be the most probable reason,
though it may actually have been absent usually.

Present methods do not show the dilute sewage water of Stock-
ton Channel to be much more produetive of Chlorophyceae than the
river. Hence such evidence as we get from this study only weakly
supports Kofoid’s suggestion (1908) that sewage laden waters favor
the increase in numbers of the group. At any rate there is clear’
indication that the Chlorophyceae contribute largely to the plankton
at all stations.

DISCUSSION OF SPECIES

Actinastrum hantzschit Lagerh.

Station I Station II Station III Daily Hourly
YAY CLAP OF Fes tian echcceen ecenreesecas 51,050 216,851 257,954 36,939 392,439

Identification satisfactory. The combined averages of two varie-
ties of this species are given here. They are recorded separately in
tables 1 to 5. The only difference noted was in size, the one recorded
as ‘‘large’’ being from two to four times as large as the typical form
measured by length of the cell. As might be expected, it is largely
responsible for the enormous average here as compared with the
silk net average (338) in Illinois. Without it, however, the average
is much greater, thus indicating a distinctly greater prevalence of
the species here. It will be noticed too that Stockton Channel with
its dilute sewage shows only about one-fourth of the average num-
bers produced by the other stations. The typical form was found
occasionally at all stations throughout the year and it also reached
its greatest abundance at the same three periods at all stations, i.e.,
March, June and September, the last showing the maximum. The
large variety came in late (April and May), produced a weak pulse
in July, and strong pulses in August and October; it dropped out
again in November. Apparently temperature affected it much more

1920] Allen: Plankton of the San Joaquin River 41

definitely than it did the typical form. Temperature is not the de-
ciding factor, however, as is shown by the fact that this variety ap-
peared last in the warmer water of Stockton Channel whence it also
practically disappeared first. Its lower temperature limit seems to
be about 14° C. Stockton Channel was distinctly less favorable to
the large form than to the typical form as is shown by the difference
in numbers being greater there than at the other two stations (tables
1 to 3). Gradations in size between the two forms sometimes made sep:
aration difficult. This species is evidently of considerable import-
ance here.

Coelastrum microporum Naeg.

Station I Station II Station IIT Daily Hourly
Average aia teers see ee San sen aneam 190,313 31,595 60,819 143,454 107,761

Identification satisfactory. Possibly includes at least two other
species. Coenobia counted. Was not found at Stations II and IIT
until July, and only five times before that at Station I. Maximum
in September at all stations. Last appearance on December 14 at
Station I, a month later than at the other places. Obviously favored
by the slightly higher temperature of Stockton Channel. The dif-
ference in averages also suggests a distinct preference for sewage
water. The maximum in September, when there was little disturb-
ance of the waters, may indicate great susceptibility to action of
strong currents and to rising and falling flood waters with their rapid
changes in temperature. The September pulse is the only distinct
one. In view of the enormous losses through the net, Coelastrwm must
be reckoned as an important planktont, though it is mainly limited
to temperatures above 15° C.

Crucigenia lauterbornii Schmidle.

Station I Station II Station III Daily Hourly
LOIS SSNS aye Er CE ee

Identification fairly satisfactory. Recorded once from Station
II, four times from Station III. Average of colonies for the year at
Station III, 14,771. Clearly too small for accurate study by net
methods. Occurrence in September and October.

Pediastrum boryanum Menegh.

Station I Station II Station IIT Daily Hourly
EASY OL ASC pees saree a 9,913 41,265 72,153 12,612 37,474

Identification inexact. Coenobia with bicornate marginal cells
but without intercellular spaces were counted under this head. Va-

42 University of California Publications in Zoology (Vou. 22

rious gradations and differences in detail make it seem probable, as
Kofoid (1908) found in Illinois, that at least two or three species
may at times be represented in the count.

Present throughout the year at all stations. Missing irregularly
in almost every month at Station I, less often at the other two. Very
few in January and December. Distinctly more numerous at all
stations than in Illinois. Sewage water evidently less favorable for
its development. All stations show a March pulse of some moment
and another in September. There is some evidence of recurrent
pulses corresponding to lunar eyeles, strongest at Station II. Maxima
in September at Stations I and II, October at Station III. The
most consistent record at Station I is in March and November, indi-
cating a preference in sewage water for temperatures from 13° C.
to 19° C. Since the only misses at Station II are in May, June
and December the same inference might be drawn as to temperature
if it were not for the fact that the representation was well sustained
through August to November. Somewhat similar conditions were
shown by Station III. At all stations the fluctuations were well
marked at all seasons. This was even more true of the daily series
at Station I (table 4) than of the regular series. The fluctuations of
the first half year may be mainly due to rise and fall of flood waters.
It is more difficult to account for those of the succeeding four months
under relatively stable conditions.

Pediastrum duplex Meyen.

StationI Station II Station III Daily Hourly
IAN OY BPO 2ns2scsccerodee neues -sesscoasens _ 301,913 686,539 837,875 703,005 1,613,919

Diagnosis inexact. All the coenobia with more or less bicornate
marginal cells showing distinet intercellular spaces were counted
under this head. The assemblage as a whole is fairly constant to a
provisional type and is quite possibly a single species. It was also
different from the preceding form in its larger numbers, greater con-
staney of occurrence and greater regularity of development. Then
too, this species has a more uniform chronology at all stations. There
is a vernal pulse with maximum in March and an autumnal pulse
with maximum in October. The marked decline after March is evi-
dently chargeable in some way to flood conditions. The steady rise
from July through August and September to the October maximum
is just as evidently due to warmer temperature and greater stability.
Though P. duplex is present at all stations through the whole year

Y

its optimum temperature is clearly near 20° C. The comparatively

1920] Allen: Plankton of the San Joaquin River 43

small numbers in Stockton Channel indicate that much sewage is
detrimental. By similar reasoning it might be concluded that Smith
Canal (Station III) supported a larger number than the river (Sta-
tion II) because more organic matter is beneficial up to a certain
point. Such a conclusion is not entirely warranted, however, be-
cause the river has an open channel with some flow while the other is
closed at one end. This difference alone might amount to more than
the organic content.

The indication of recurrent cycles due to lunar influence is more
distinet with this form than the preceding though they are not at all
regular even here (tables 1 to 3). The daily series shows an interesting
suggestion of recurrent pulses at intervals of four to six days (table
4). In the hourly series (table 5), it appears that both P. boryanum
and P. duplex reach maxima in the afternoon, suggesting diurnal in-
fluence of light and temperature. The data, however, do not war-
rant a conclusion. The hourly series needs extension.

There is no very definite relation of Pediastrum pulses to the
volumetric pulses.

Pediastrum simplex Meyen.

Station I Station II Station III Daily Hourly
DENN REE 2 eee 7,422 32,333 36,044 16,796 49,189

Identification fairly satisfactory. Coenobia having marginal
cells with one median spine were counted under this head. Probably
only one species included. Fewer than either of the foregoing forms
at all stations, except that it exceeds P. boryanuwm in both the daily
and hourly series. Rare at Station I through the first six months,
considerable numbers there in July, very few in August, maximum
in September, rare thereafter. Occurrence at the other two stations
similar, except that the numbers were larger. So far as the records
go they indicate the same general characteristics of distribution as
mentioned for the foregoing species.

It is evident that Pediastrum is a very important genus, both
numerically and volumetrically in the local plankton. The greater
numbers here, as compared with Illinois, indicate that local condi-
tions are better suited to this genus, but it is also true that this may
have been an exceptionally favorable year. It is worth noting in
this connection that the representation of Pediastrum is proportion-
ally greater here as compared with other forms found in both see-
tions and this fact favors the view that it is really more characteristic
of our plankton.

44 University of California Publications in Zoology (Vou. 22

Since the genus shows very distinet response to flood conditions,
perhaps it is worth while to emphasize that point, especially in view
of the fact that there are no reliable water gauge or tide records
available. The rapid decline of numbers in March follows very closely
on the arrival of the heavy stream flow from the mountains. The
rapid rise in numbers in June is just as closely connected with the
disappearance of flood waters.

Raphidium polymorphum Fres.
Station I Station II Station III Daily Hourly
Atvera ge Uist a. ee ea 131,037 48,363 47,002 129,935 29,744

Diagnosis inexact. Probably includes two or more species. Occur-
rence rare in winter months at all stations. Thrives best in Stockton
Channel (Station I). While the numbers are large at times the ree-
ords are so fragmentary, particularly in view of the enormous num-
bers escaping through the net, that no generalization can be made.
There is, however, some support for Kofoid’s observation (1908) that
the organism has an optimum temperature above 15° C. Furthermore
the larger numbers in Stockton Channel indicate the benefits of sewage.

Richtericlla botryades Lemm.
Station I Station II Station III Daily Hourly
JANOS Gt lise esececresstoreee 5,723 20,806 213499"

Identification satisfactory. Occurrence at very irregular inter-
vals at all seasons of the year and at all stations. Rather large num-
bers at times. Records too scant to warrant conclusions. Percentage -
captured evidently very small.

Scenedesmus obliquus Kiitz.

Station I Station II Station III Daily Hourly
319,244 43,593 63,234 305,638 166,826

Diagnosis sometimes confused on account of apparent intergradat-
ions. May perhaps include two or three species. Rare in January
and February. Few in Mareh, April, May and December at all sta-
tions. Maximum in June at Station I, although the numbers are best
sustained there through September and October. Other stations also
show greater constancy in that period. Vernal pulse very slight so far
as silk net can show. Average silk net catch in Illinois was given by
Kofoid (1908) as 673. The largest Stockton Channel catch is about
500 times as great. If the silk net only captures a fraction of 1 per
cent of the Scenedesmus present the numbers there were certainly
enormous. In spite of the losses through the net it is at least safe
to say that sewage and moderate temperature, 15° C. to 20° C. are

Average

1920] Allen: Plankton of the San Joaquin River 45

especially favorable to this form. There are recurrent pulses appar-
ently but the uncertainty as to the percentage of the population on
record makes all such points unreliable.

Scenedesmus quadricauda Breb.
’ Station I Station II Station III Daily Hourly
TNS CTEM REY ier seep ee eee 772,520 224,775 363,308 786,615 366,203

Diagnosis sometimes confused by intergradations. Only a small
percentage in doubt. Losses through net certainly very heavy, prob-
ably over 99 per cent according to Kofoid’s results (1908). Hence in-
ferences are to be made with caution as in case of the preceding
species However, the greater continuity of the record for this species
makes intelligent discussion possible.

A vernal pulse in March and an autumnal pulse culminating in
October were quite well marked at Stations II and III. The vernal
pulse is not clear at Station I and the autumnal maximum was reached
in November. In no ease was there very heavy representation until
about June. At Station I a distinct decline through July and August
suggests marked limitation by higher temperatures. Sewage water
with temperature between 15° C. and 20° C. is evidently nearly ideal
for Scenedesmus.

There is rather distinct indication of monthly pulses at all three
stations (tables 1-3). These do not, however, correspond very closely
with Pediastrum pulses, so it is hardly worth while to attempt to
establish any connection with linar cycles from present data.

This species was rarely absent from any station, never from Sta-
tion I. Its appearance there in large numbers through the winter
months clearly marks it as perennial in this locality. While the records
of this and the preceding species are fragmentary so far as the whole
population of the genus is concerned they show very clearly that the
genus is of first rate importance in our waters through a large part of
the year and especially where there is much organic matter.

Schroederia setigera Lemm.
Station I Station II Station III Daily Hourly
Arena ey elie ute ees 3 35,724 4,099 5,343 43,587 16,276

Identification satisfactory. Probably only small percentage cap-
tured by the net. Only recorded six times at Station III and three
times at Station II. Irregular occurrence from last of April to end
of year at Station I. Well represented through June and part of
November. Not enough data to indicate more than a preference for
dilute sewage.

46 University of California Publications in Zoology [Vou 22

Selenastrum bibrainum Reinsch.

Identification satisfactory. Recorded five times from Station I in
small numbers. Once at Station III. Evidently too small to be held
by the net.

The following forms were recorded only once or twice in small
numbers or else were noticed in living material.

Botryococcus sp. Once at Stations II and III. May have been overlooked.
Bulbochaete sp.
Chodatella ciliata. Lemm. Once at Station IIT.
Crucigenia quadrata Morr. Once in daily series.
Crucigenia rectangularis Chod.
Crucigenia sp. Once at Stations II and III.
Dimorphococcus lunatus A, Br.
Draparnaldia plumosa Ag.
Golenkinia radiata Chod. Once at Stations I and III.
Lagerheimia wratislaviense Schroed. Once at Station I.
Lauterborniella elegantissima Schmidle. Once at Stations I and II.
Monostroma sp. Once at Station ITI.
Nephrocytium agardhianum Naeg.
- Pleurococcus sp.
Sorastrum spinulosum Naeg.
Stigeoclonium (?) sp. Twice at Stations I and II.
Tetrastrum sp. Once at Station ITT.
Ulothrix sp. Twice at Station I. Doubtful identification.

Bacillariaceae
Plates 7-9
Station I Station II Station III Daily Hourly
Number of forms recorded 44 58 53 25 32

Av. number per cu. meter .....22,609,062 39,478,317 36,826,859 28,055,459 29,029,248

The diatoms are distinctly the most abundant group of organisms
in San Joaquin plankton so far as present methods show. According
to these records they outnumber Schizophyceae 14, 33 and 18 to 1;
Chlorophyceae 12, 28 and 21 to 1, and Mastigophora 6, 14 and 7 to 1
at Stations I, II and III respectively, thus making them appear to
have a still more prominent place in the plankton than they had in
Illinois. There were always some diatoms in every collection at all
stations throughout the year.

There was only one very distinet pulse at each station. At Station
I this appeared in May, while at the other stations, where it was larger
but less abrupt, it came in August. There is no way of telling from
these records whether this difference was due to better temperature or
to more stable conditions at those times. The fact that Smith Canal

1920] Allen: Plankton of the San Joaquin River 47

resembles the river in temperature and is more like Stockton Channel
in stability suggests a stronger influence of temperature. A glance
at plates 7, 8 and 9 shows a marked resemblance of all three stations
in low production of diatoms through the first twenty and the last six
weeks of the year. All show comparatively heavy production through
all the intervening period though the culmination is more nearly
median in this time at Stations II and III. This characteristic of dis-
tribution is common to all the algae. These major pulses are evidently
composite though the exact location of their maxima may be due to
single species. The diatoms as a group show more marked indication
of pulses recurrent at approximately four weeks intervals than do any
other algae.

One notable difference in the three stations is that the total pro-
duction is less at Station I than at either of the others. Except for
the difference in the location of the maxima this was shown through-
out the year. The production in winter and spring is continuously
less at Station I. Although the maximum came earlier it did not
appear so abruptly nor decline so quickly as at both Station II and
Station III. Sewage seems to be detrimental, as does a temperature
above 23° C. However, it is not certain that temperature is the deter-
mining factor, for stagnation of the water probably has a deleterious
effeet more quickly in sewage water than in water comparatively clean.
It seems quite possible that simultaneous strong flood currents through
Stockton Channel and the river would hold the maximum back to a
similar date. Some light on this question may be expected from the
1914 series which covers a time of heavy flood. Again there is the
possibility that predatory organisms, notably Entomostraca, cut down
the supply of diatoms in spite of favorable conditions for develop-
ment. The maximum for Entomostraca comes at the time of decline
of production of diatoms in the summer (plates 3, 9).

The fact noted by Kofoid (1908) that the volumetric measure
shows mainly the zodplankton is especially important here because
there is not sufficient check by other methods to give any idea of the
relative loss of phytoplankton through the net. The diatom count cor-
responds pretty closely, in its rise and decline, to the volumetric ree-
ord (plates 1, 7, 8, 9) at Station II and III but no very definite rela-
tion appears at Station I. This might be expected from the fact that
a moment’s examination gives one the impression that the Stockton
Channel plankton is distinctly animal and the river plankton mainly
plant.

48 University of California Publications in Zoology (Vou. 22

While the records of Station I might lead one to think there pos-
sibly were reproductive cycles and successive rest periods as suggested
by Kofoid (1908) the records for Stations II and III point rather the
other way. The strong and somewhat rapid rise through June and
July to a maximum in August with a similar decline to the winter
level suggests, indeed, that factors of the immediate external environ-
ment are responsible and that increase in numbers would continue
indefinitely if the proper balance of temperature, food materials and
natural enemies could be secured along with sufficient removal of
injurious accumulations.

The number of forms of diatoms listed (98) may seem unwar-
ranted inasmuch as there could be no hope of aceurate determination
of all the species present. The large list was the cumulative result of
an effort to give expression to differences noted. The futility of it was
not realized until too late to change it easily. After all, it happens
that there are only a few forms found frequently and in great num-
bers and most of these ean be approximately determined.

Twenty forms occur at one or more stations with sufficient con-
tinuity to give the impression that they are true planktonts. These
are Asterionella gracillima, Bacillaria paradoxa, Cyclotella spp. Cyma-
topleura solea, Cymbella affinis, Cymbella cymbiformis, Cymbella
tumida, Fragillaria capucina, Gyrosigma kiitzingii, Gyrosigma scal-
proides, Melosira granulata, Melosira varians, Navicula alpestris,
Navicula bacillum, Navicula gracilis, Nitzschia acicularis, Plewros-
tauron parvulum, Surirella spp., Synedra radians, and Synedra ulna.
Distinctly the most important of these are Asterionella, Bacillaria,
Cyclotella, Melosira and Synedra, all of which are satisfactorily de-
termined as to genus, though the species are sometimes uncertain.
Most of the other genera just mentioned are also believed to be cor-
rectly designated. Much of the specific determination is largely guess
work for the inexperienced observer under the conditions of counting.
Fortunately such errors do not materially affect the generalizations
within reach of this present study. Schénfeldt’s ‘‘ Bacillariales’’ in
the Siisswasserflora Deutschlands series was the main dependence for
identification.

1920] Allen: Plankton of the San Joaquin River 49

DISCUSSION OF SPECIES

Asterionella gracillima Heib.

Station I Station II Station III Daily Hourly
Average Benes ocean eo eeeeena 344,378 1,743,406 1,381,583 3,516 12,206

Identification certain. Records show numbers of colonies. Average
size of colonies at Station I was three, at Station II four, at Station
III three. Two forms were noted, a typical and a large form. They
were recorded separately in tables 1 to 5 though the above averages
are for the two combined. As in the case of Actinastrwm the two were
alike except for size but the larger was usually only about 50 per cent
larger, rarely twice as large. There were sometimes all gradations in
size but in most cases the distinction was plain. It will be noticed by
reference to the tables that the pulses ran somewhat the same with
both forms at all stations but that the large form appeared rather
late at all stations and that it was only prominent in May and June
at Stations I and II, June at Station III. Perhaps this condition
warrants the inference that the large form is favored by a tempera-
ture above 20° C. especially since the June maximum comes at the
highest temperature (26°5 C. and 29° C. respectively at Stations II
and III) and very nearly so at Station I (22° C.).

Both forms were practically absent at all stations through July,
August, September and October. Both reappear in November. The
typical form is abundant at all stations except during the four months
just mentioned. At Station I it showed a strong pulse in January and
a maximum pulse in March. Another strong pulse came in December.
At both of the other stations the maximum pulse came in February and
a very strong pulse in December. If both forms be counted together,
Station II is seen to have almost as large a pulse in June as in Febru-
ary. The combination also shows a very large pulse in June at Station
Ill. The abrupt disappearance of both forms in July at all stations
must be due to some other factor than temperature since the tempera-
ture change is neither abrupt nor very marked. Stagnation may have
a strong deterrent influence. There are fairly well marked, recurrent
pulses at four to six weeks intervals at all stations.

Very few single cells of Asterionella were recorded. This can be
accounted for in two ways: first, escape through the net; second, con-
fusion with other single cells.

50 University of California Publications in Zoology |Vou. 22

Amphiprora alata Kiitz.
Station I Station II Station IIT Daily Hourly
PARTE PG Ve ctececactenccccencnte teehee 12,847 4,161 21,057 8,373 268,548

Identification satisfactory as to genus and probable as to species.
A. ornata is probably ineluded in the count at times, as it was some-
times found by the writer and was also identified in 1915 eatehes by
Professor C. J. Elmore. Probably heavy loss through the net. So far
as net catches show it is not so very important. Occurrence rather
seattering at all stations though fairly constant in latter part of the
year at Station I. Maximum at Station I in May, at other stations in
June.

Bacillaria paradoxa Gmel.

Station I Station II Station IIT Daily Hourly
ONG GSE) i ee 8,547 1,647,817 984,810 28,857 254,916

Identification positive. Colonies usually large, henee probably
very little loss through the net. Occurrence scattering at Station I,
fairly constant through the year at Station II and III where it was
abundant through the second half year. Maximum in July at Station
I, August 2 at Station IT, and August 9 at Station III. Conspicuous
minor pulses in April and December at Station Il; April, September
and December at Station III. The sudden jump into prominence at
Stations IT and III in July and the reappearance at Station I, where
it had been absent more than two months, seems to indicate favorable
influence of stagnant water. Retardation by sewage is also indicated.
Higher temperatures may have a bearing, though the temperature
change is not nearly so abrupt as the change in numbers of Bacillaria.
There are no very strong indications of recurrent pulses at any station,
but Station II shows them slightly.

B. paradova is certainly one of the most important planktonts of
the river after the flood season. Colonies containing less than ten indi-
vidual cells were comparatively rare, certainly not more common than
those consisting of more than twenty-five. It would be very safe to
estimate the average number of cells captured at ten times the aver-
age recorded for the colonies. This would bring B. paradova into the
foremost rank of planktonts, numerically, at Stations Il and III. Only
Cyclotella sp. and Melosira granulata would clearly exceed it in num-
bers by that reckoning. The other forms which might do so are not
identified with sufficient certainty. :

Cocconeis pediculus Ehrbg.

Determination probable. May inelude other species. Losses through
net undoubtedly heavy. According to the records not a very import-

1920] Allen: Plankton of the San Joaquin River SL

ant planktont. Occurs five times at Station I, thirteen times at Station
II with a maximum of 105,792 at the end of May, and four times at
Station IIT.

Cyclotella spp.
Station T Station II Station IIT Daily Hourly
YASS OTE Cli Bet isc evac wad eae 15,052,042 6,335,253 6,865,673 13,191,571 5,415,717

Genus identification certain. Probably includes three or more
species, certainly two. Impossible to distinguish species completely
while counting though the attempt was made throughout the whole
series for 1913. It was finally decided that more accurate conclusions
were probable if all counts were thrown together. So few individuals
are retained by the net that any conclusion must be taken with cau-
tion even then. Present through the year in all collections at all sta-
tions. Wide range in size. Most of them nearer the smaller limit as
noted by Kofoid (1908).

Maximum numbers at Station I in June, at both of the other sta-
tions in October. One minor pulse is of unusual interest because it
falls on January 19 at all three stations (tables 1-3). There is no
ereat change in temperature to account for it but it came after a week
of cloudy weather with more or less rain on the five days immediately
preceding. It would seem that the condition of falling flood is respon-
sible in this ease. Possibly the June maximum at Station I can be
explained in the same way. No such local conditions apply in ease of
the October maximum at Stations II and III. There was, however,
about that time higher water than there had been for several weeks
previous, due to the inflow from mountain tributaries enlarged by the
early mountain rains.

So far as our present records show, the optimum temperature seems
to be nearer 20° C. than 15° C. as found by Kofoid (1908) in Illinois.
Sewage contamination, stagnation and flood waters all appear to be
factors of marked importance in determining maximal production of
this diatom. There is no indication of a maximum corresponding to
the volumetric maximum (plate 1) such as was observed in Illinois,
but this may be due to the small numbers caught as compared with
those escaping.

Cymatopleura solea Breb.
Station T Station TI Station IIT Daily Hourly
PAS G02 Cetera tees sbenacr ees eneze 219 11,043 BEL) EAS teri Aine | RIOR Sete ca

Identification satisfactory. Recorded only six times at Station I,
but found at intervals through whole year at other stations. Numbers

52 University of California Publications in Zoology |Vou. 22

rather small. Loss through net considerable. Maximum in May at
Station IT with a well defined pulse. Maximum in August at Station
III where there were no definite pulses. May be adventitious. Tem-
peratures at maxima were above 20° C.

Cymbella affinis Kiitz.

Station I Station II Station IIT Daily Hourly
IAS OY ALC -5-<cencccrac-sscccerscenscenete 1,283 73,671 10,276 516 20,345

Identification uncertain. This was a very small Cymbella rela-
tively few of which could have been retained by the net. Recorded only
eleven times at Station I. Abundant in March, April, May and June
at Station II but missing in January, February and December. Scat-
tering in other months. Maximum on May 31 in a well developed
pulse. More irregular in oceurrence at Station III where the maxi-
mum came in April. Probably an important planktont numerically.
Evidently not favored by sewage.

Cymbella cymbiformis Kiitz.
Station I Station II Station IIT Daily Hourly
BN ACY Ti oe ee 446 8,382 4,331 310 4,561

Identification uncertain. Probably includes more than one species
not distinguishable while counting. Recorded thirteen times at wide
intervals at Station I, in small numbers. Small numbers recorded in
every month of the year at Stations I and III with a fairly constant
record through May and June at Station II. Apparently of minor
importance.

Cymbella tumida Breb.
Station I Station II Station IIT Daily Hourly
INV CHEN RO) aro eetrcrete- cater tec acee 2,245 23,677 8,547 619 5,546

Identification uncertain. Probably includes more than one species.
Records scattering and in small numbers at Station I. Small numbers
but fairly constant, May to September, at Station III. Reeorded in
every month except January and September at Station IT. Maximum
in May. Probably of minor importance.

Epithemia ocellata Kiitz.
Station I Station II Station IIT Daily Hourly
PS GYEND, Geren treere sects 1,015 15,713 8,579 413 8,630

Identification fairly satisfactory. Probably two other species in-
cluded. Loss through net heavy. Numbers small and records seatter-
ing at Stations I and III. Representation fairly constant at Station
II except in January, February and December. Maximum in May on
a well marked pulse. May be adventitious since the maximum comes
on the waters of the mountain flood.

1920] Allen: Plankton of the San Joaquin River 53

Fragillaria capucina Desm.

Station I Station II Station IIT Daily Hourly
EXSY GS CYR Sonera ee 1,154 26,252 QO\OGB) seen 9,123

Identification satisfactory. Colonies usually rather large, seldom
less than six cells. Most of the colonies probably retained, though loss
of small colonies and single cells may have been heavy. Numbers very
small at Station I and records few after April. Numbers larger and
occurrence more constant at Stations II and III, though frequently
missing there after August. Maximum in May at both places. No other
pulse of particular note. Apparently not very important.

Fragillaria crotonensis Kitton.

Station I Station II Station IIT Daily Hourly
PASVIOT AS Cessna ese cece tessa nenacee 92 4,516 WeBB8" Valse se tee

Identification satisfactory. Colonies not very large. Occurrence
twice at Station I, seven times at Station II at wide intervals and nine
times at Station IIIT. The records at Station III are mainly in Sep-
tember, October and November. Evidently unimportant here in spite
of considerable escape from net in catches.

Fragillaria spp.
Station I Station II Station IIT Daily Hourly
DNS IQTEN AO ete ae eee pee 92 27,832 290 103) “Resekeees

Probably most of those included under this heading belonged to
F’. virescens. Occurrence only twice at Station I. Represented at
Station II by some fairly large numbers widely scattered. Colonies
small. Apparently adventitious.

Gomphonema constrictum Ehrbg.

Station I Station II Station IIT Daily Hourly
PAV OT AG Cleese eek ae eee 1,322 22,094 282 103 8,138

Identification uncertain. Numbers small. Losses through net heavy.
Recorded seven times at Station I at irregular intervals. Well repre-
sented in May and June at Station II. Recorded seven times at
Station III in very small numbers.

Gomphonema spp.

Station I Station II Station IIT Daily Hourly
PAV Ona oi Cure eater ees 7 A 65 6,419 5,000 MOST eee

Under this heading are included some members of this group which
could not be placed satisfactorily. Probably most of them were G.
subclavatum. Apparently there were five or six species of this genus
observed at various times and it probably has some importance though
it may be adventitious.

54. University of California Publications in Zoology (Vou. 22

Gyrosigma acuminatum Kiitz.
Station I Station II Station IIL Daily Hourly
Rrvecne heat ato ee 1282 «24,920 22,157 ceeseneceaasee 12,207
Identification uncertain. Recorded seven times at Station I at wide
intervals, twelve times at Station II and Station IIT. Grouped in
August at Station III. Considering amount of loss through net may
have some importance though evidently adventitious.

Gyrosigma kiitzingti Grun.
Station I Station II Station IIT Daily Hourly
ANGIE QG® s-cctcscc-cesecscecternece aes 3,330 102,723 70,433 1,032 87,974
Identification probable. Losses through net very heavy. Recorded
frequently in small numbers in every month except February, June,
and July at Station I. Maximum there in September. Occurred regu-
larly with only one or two breaks at Stations Il and III. Maximum
at Station II in late August in a well developed pulse. Maximum at
Station III in late July at the beginning of a similar pulse which
almost reached the maximum again at the same time with Station II.
Minor pulses at from two to six weeks intervals through most of the
year were rather prominent at both stations. Apparently this is a
planktont of some importance throughout the year since the percent-
age retained by the net is undoubtedly small.

Gryrosigma scalproides Rabenh.
Station I Station II Station III Daily | Hourly
PANY OR 20°) Weceeectnectscekcaceeteence ose 13,733 31,294 206,444 826 480,133
Identification satisfactory. May include G. spenceri W. Sm. Loss
through net heavy. Reeords seattering at Station I especially in first
seven months. Maximum in August with a well developed pulse.
Recorded in every month up to September and not later, at Station IT,
with a sharp pulse in August. Recorded every month after January
and February at Station III though seattering until late July. Very
strong pulse in August reaching apex on August 23. Seems to be,
like other Gyrosigma, a seasonal planktont favored by temperatures

above 20° C. and injured by sewage.

Melosira granulata Ehrbg.
Station I Station II Station III Daily Hourly
VAGOr ates) Meee ee noe 2,305,175 25,163,409 22,821,226 1,880,779 18,144,471
Identification certain. Mostly variety spinosa. Loss through net
high. Kofoid (1908) says about 98 per cent in Illinois and it is doubt-

On

1920] Allen: Plankton of the San Joaquin River 5

less nearly the same here. His observation that silk catches showed
the same seasonal routine as the filter catches makes it seem probable
that we can use our counts here with some confidence in the conelu-
sions they may indicate. M. granulata is recorded in every collection
through the whole year at all stations. At all stations the numbers are
comparatively small until April, though the million mark was reached
a few times before that date at each. The earliest count of this size
was at Station I in January. The maximum at all stations falls on
September 6, after a considerable period of rather high temperatures.
A temperature of 25° C. or higher and stagnation of the water are at
least two favorable factors in production. Since Station I has less
than 10 per cent of the number at the other stations at that time it
seems equally clear that sewage is detrimental. So far as the 1913
collections show, there is a rather definite growth period in September,
though there are several prominent pulses through the warm season
just as there were in Illinois. Minor pulses at from two to six weeks
intervals were quite prominent characteristics of the occurrence of
this organism everywhere. The steady decline from the September
Maximum in spite of occasional minor pulses strongly supports
Kofoid’s view that temperature is the most potent factor influencing
production.

The time of maximum production corresponds fairly well with the
time of greatest production of total plankton mass (plate 1), though
the largest number is reached a little later. It is, however, coincident
with the maximum of the total count of organisms. To this last total
M. granulata contributes largely since it is the most abundant local
planktont at Stations II and 111. Owing to its large numbers it also
contributes a very considerable mass.

There was a good deal of variability in this species. Spines varied
from very coarse, prominent projections to none. Granulation was
very prominent in some eases, absent in others. There was a wide
variation in size. This was so great that for a time a small form
was listed as M. granulata A and counted separately (tables 1-3). By
so doing the main count was fairly well restricted to the more nearly
typical granulata and to the variety spinosa. Sometimes these seemed
to be nearly equal in numbers but usually the spinous form was less
noticed than the other.

Various encumbrances of the filaments were common. None of
these were certainly identified. The only one counted was a small
Rotifer egg listed as Diurella sp., by guess.

56 University of California Publications in Zoology [Vou. 22

No effort was made to determine the average number of cells in a
filament but it was probably not less than five. The cells composing a
filament were much longer in proportion to width than they were fig-
ured in the literature consulted. A common form about the time of
maximum numbers had eells about five times as long as wide.

Melosira varians Ag.
Station I Station II Station IIT Daily Hourly
Averaget cst eee. 4,682 233,227 93,884 619 9,123
Identification satisfactory. Losses through net heavy. Occurrence
at Station I quite irregular in small numbers, with a maximum in
April. Main production at other stations in first six months, two or
three misses after that time at both. Maximum at last of May in Sta-
tion II after steady increase for several weeks. Maximum in March
at Station III, appearing rather abruptly. Recurrent pulses at two
to six weeks intervals at both stations. A large September pulse is
only indication of response to conditions similar to those of M. granu-
lata. In fact the most favorable temperature seems to be near 18° C.
or between 12° C. and 20° C. There is a strong pulse in late Decem-
ber at Station II which follows about a month of temperatures below
10° C. Hence it is certain that the two species are distinctly different
in the responses to temperature. While MZ. varians is overshadowed in
produetiveness by M. granulata, it is yet to be reckoned an important
planktont here.

Navicula affinis Ehrbg.
Identification doubtful. Losses through net heavy. Recorded

eleven and eight times at Stations II and 111 respectively in rather
small numbers. Not sufficient data for discussion.

Navicula alpestris Grun.
Station I Station II Station IIT Daily Hourly
PASV OLED O\Wacetee=--ct ca Puescaetesccseccre 6,746 76,645 29,979 3,929 55,3857
Identification doubtful. Losses through net very heavy. Occur-
rence at Station I in small numbers and very scattering through the
year. Not much better record at Station III. Appears in March at
Stations II and III. Maximum at Station II on May 31 after two
months of fairly steady increase, followed by slow decline to August.
Seems to be favored by moving water. Its long continued presence
seems to indicate that it is a true planktont, and it is probably of
considerable importance.

1920] Allen: Plankton of the San Joaquin River 57
Navicula bacillum Ehrbg.

Station I Station II Station III Daily Hourly

PAWerap ele: 0.0 meee 56,910 169,399 42,869 16,079 65,103

Identification doubtful. Percentage retained by net must be very
small. It may seem a waste of time to list so many diatoms of uncer-
tain identity, especially of the smaller forms, but it is the writer’s
opinion that to do so may serve two purposes: first, to give a faint idea
of the large number of forms present; second, to show how very many
forms there are beyond the reach of ordinary quantitative methods.
For example the small diatom listed under this present heading was
quite probably present in one hundred times the numbers recorded,
possibly more. It appears in April at all stations and is erratic in
appearance and numbers after that. The maximum appears in Sep-
tember at Station I and Station III but in June at Station II. In the
circumstances no safe conclusions ean be drawn from such a small
organism.

Navicula didyma Ehrbg.

Identification doubtful. Losses through net heavy. Recorded once
at Station I, ten times at Stations II and III, always in small numbers.

Navicula dubia Ehrbg.

Identification doubtful. Losses through net heavy. Recorded six
times at Station I, four times at Station II and five times at Station
III in small numbers.

Navicula gracilis Ehrbg.
Station I Station II Station III Daily Hourly

TNS CSN eae eee eee 209,568 722,906 1,514,448 166,204 1,177,953

Identification uncertain. Losses through net very heavy. Re-
corded in every month at all stations. Maximum in August at all
stations on a rather abrupt rise in numbers. Certainly favored by
higher temperatures and quiet water but hindered by sewage. These
points are shown by the remarkable development at Station III with
quiet water but with little sewage and by the fact that the large num-
bers shown by Station II through May probably came from the
washing out of some sloughs where there had been a time of quiet
just preceding. Recurrent pulses are fairly well marked. This form
is evidently very important numerically. The count may include
several species.

58 University of California Publications in Zoology (VoL. 22

Navicula sp.

Under this head are included a number of forms thought to be
Navicula. Some of these were first recorded as N. oblonga, N. pusilla,
N. rhomboides and N. smithii, but the numbers were few and the iden-
tity uncertain, so it was more convenient to place them this way.
There is nothing of particular importance to be obtained even from
the combined record.

Navicula viridis Ehrbg.

Station I Station II Station III Daily Hourly
ING OER OY pe pes sire epee ieee en 169 27,659 Cf 985

Identification satisfactory. Losses through net probably heavy.
Numbers very small at Stations I and III. Maximum in May at
Station II where the numbers were larger and there were few col-
lections showing none. For purposes of discussion it is unfortunate
that the only Navicula named with confidence presents too few num-
bers to warrant much attention.

Nitzschia acicularis Kiitz.

Station I Station II Station IIT Daily Hourly
PAVOTA PO. oo scnnsesececeseneseeeeseoese ee 2,878,662 316,042 476,223 4,390,368 600,166

Identification satisfactory. Probably very small percentage re-
tained by net. Present throughout the year at all stations. Maxima
in June at Stations I and II, in late August at Station III. Numbers
well sustained through summer at all stations, with a conspicuous
September pulse. Evidently a summer planktont favored by tem-
peratures above 20° C. Just as evidently favored by the sewage at
Station I as shown by the enormous averages there in comparison with
the averages at other stations. Recurrent pulses fairly well marked.
Certainly of great numerical importance though its small size would
keep the volumetric showing low.

Nitzschia spp.

Under this heading are discussed four or more species of Nitzschia
all but one of which are doubtful as to identification. Nitzschia angu-
laris was satisfactorily determined but N. sigma, sigmoidea and vermi-
cularis were all somewhat doubtful, at least sometimes. They were
all listed separately in the tables but the occurrence was so erratic and
the probable losses from the net so heavy that it hardly seemed worth
while to attempt to draw any conclusions from the records of any of
them. It might be noted, however, that all Nitzschia are favored by
higher temperatures, but that none of these do well in sewage, N.

1920] Allen: Plankton of the San Joaquin River 59

acicularis being exceptional in that respect. It may also be the only
true planktont, all the others being adventitious.

Pleurostauron parvulum Grun.

Station I Station II Station IIT Daily Hourly
PAVOT AGO) jaatcncdicscccactccteaceaseneae 34,372 261,925 149,609 310 28,521

Identification probable. Probably very small percentage retained
by net. Almost entirely absent from Station I through July, August
and September. Few during last half of year. Maximum in May
at Stations I and II and in March at Station III. Heavier represen-
tation in first half year at all stations. Hence it appears to be favored
by flood waters and lower temperatures. Larger numbers at Station
II and III indicate bad effects of sewage at Station I. Must be of
numerical importance.

Stauroneis phoenicenteron Ehrbg.

Station I Station II Station III Daily Hourly
PAV ON EO Cesc sane cca eecectccessss 115 5,746 W320) cea 8,138

Identification satisfactory. Losses through net probably heavy.
Found at various times of year at all stations but in small numbers.
Recorded only six times at Stations I and III. Maximum in May at
Station II. Probably adventitious.

Surirella spp.

Station I Station II Station IIT Daily Hourly
DAV CTE @) secre cc teecenteccress 14,270 753,747 404,242 12,303 305,828

Genus identification certain. Probably at least four species in-
eluded under this heading. Losses through net heavy. Present
through year at all stations. Maximum in August at Stations II
and III. The representation at Station I was light and scattering
and though the maximum came in May it cannot be considered very
important, especially since large pulses came at that time at the
other stations. This planktont is evidently favored by temperatures
above 20° C. and retarded by sewage. Both in numbers and volume
it makes an important contribution to the plankton population.

Synedra radians Kiitz.

Station I Station II Station III Daily Hourly
PACT AG Clucestcescaszsssnccssseede sates 389,043 144,508 194,502 1,126,141 486,236

Identification doubtful. Probably very small percentage retained
by net. This is one of those very small forms so difficult to handle
in a count. Its appearance on the record at mid-July is simply due
to the fact that its continued presence seemed to demand some definite
notice. The occurrence before that date must be ignored because of

60 University of California Publications in Zoology [VoL 22

failure to decide to record it. There is enough record to indicate
that it is a warm weather form and not nearly so well represented in
the colder months.

Synedra ulna Ehrbg.

Station I Station II Station IIT Daily Hourly
JANV GVA QO) woz censtectannescoseesererstesee 655,730 730,339 744,781 2,351,197 305,169

Identification uncertain. Probably includes at least three or four

other species with possibly some similar genera. This probably ae-
counts for the similarity of numbers and distribution at all stations.
Maximum in August at Stations II and III, in June at Station I
with a large pulse in August. Certainly favored by higher tempera-
tures. Losses through net heavy. An important local planktont.

Tabellaria spp.

Identification of genus satisfactory. Occurrence at all stations
rare. Evidently unimportant here. It was thought that both 7.
fenestrata and T. flocculosa were recognized a few times. This genus
is apparently no more at home here than Kofoid (1908) reported it
to be in Illinois.

The following forms of Bacillariaceae were recorded only once
or twice at the three stations, or were thought to be recognized in
living material:

Amphora coffeaeformis Ag. Once, I and twice, IIT.
Amphora sp. Once, I and IIT.

Cocconeis placentula Ehrbg. Once, II.

Coeconeis sp.

Coscinodiscus sp. Once Stations I and III and daily.
Cyclotella schroeteri Lemm. Once, I.

Cymbella helvetica Kiitz. Once, I} and IIT.

Cymbella lanceolata Ehrbg.

Cymbella parva W. Sm. Twice, I, once at II and III.
Cymbella pusilla Grun.

Cymbella prostrata Berk.

Denticula sp.

Diatoma sp.

Diatoma vulgare Bory. Twice, I, once at III.
Diatomella sp. Grev. Once, I and II.

Epithemia granulata Ehrbg.

Epithemia sorex Kiitz. Once, IIT.

Epithemia sp.

Epithemia turgida Ehrbg. Once, II.

Eunotia flexuosa Kiitz. Once at Station I, twice at III.
Eunotia major W. Sm. Once, III.

Eunotia pectinalis Kitz.

Fragillaria mutabilis.

1920] Allen: Plankton of the San Joaquin River 61

Gomphonema acuminatum Ehrbg. Once, ITI.
Gomphonema olivaceum Lyngb. Twice, III.
Gomphonema subelavatum Grun.

Gyrosigma attenuatum Kiitz. Once, IIT.
Mastogloia braunii Grun. Twice, II and III.
Mastogloia sp. Once, II.

Melosira subflexilis Kiitz. Once, II.

Navicula helvetica J. Brun. Once, ITI.
Navicula lanceolata Kiitz. Once, II.
Navicula oblonga Kitz.

Navicula pusilla W. Sm.

Navicula rhomboides Ehrbg.

Navicula smithii Breb.

Nitzschia dubia W. Sm. Once, II.

Nitzschia gracilis Hantzsch. Once, TIT.
Pinnularia acrosphaeria Breb. Once, III.
Pleurostauron obtusum Lagerst. Once, I and II.
Rhizosolenia longiseta Zach. Once, I and III.
Rhopalodia gibba O. Miill. Once, I, twice, II.
Rhopalodia paralella O. Miill. Once, II.
Stephanodiscus sp. Twice, I, once, IT.
Surirella spiralis Kiitz. Once, IT.

The following list of forms, identified by Professor C. J. Elmore
of Grand Island College in Nebraska from material collected in 1915
and sent to him for naming, will prove of interest for comparison.

Achnanthes lanceolata (Breb) Grun.
Amphora ovalis.
Asterionella gracillima Heib.
Amphiprora ornata Bailey.

' Bacillaria paradoxa Gmel.
Ceratoneis arcus Ehr.
Coceconeis pediculus Ehr.
Cyclotella meneghiniana Kiitz.
Cymatopleura solea (Breb) Grun.
Cymatopleura elliptica (Kiitz) W. Sm.
Cymbella gastroides Kiitz.
Cymbella lanceolata.
Cymbella pusilla.
Diploneis (Naviecula) elliptica.
Eneyonema turgidum (Greg) Grun.
Epithemia gibba (Ehr) Kiitz.
Epithemia ocellata Kiitz.
Epithemia turgida Ehr.
Eunotia robusta.
Fragilaria capucina Desm.
Gomphonema montanum.
Gomphonema constrictum Ehr.
Gyrosigma kiitzingii (Grun) Cl.
Gyrosigma parkerii.
Gyrosigma scalproides (Rabenh) Cl.

62 University of California Publications in Zoology (Vou. 22

Gyrosigma spencerii (W. Sm) Cl.
Homoeoecladia (Nitzschia) acicularis.
Homoeocladia amphioxys. 5
Homoeocladie obtusa.
Homoeocladia sigma.
Homoeocladia spectabilis.
Homoeocladia tryblionella,
Melosira granulata (Ehr) Ralfs.
Melosira crenulata Ehr.

Melosira distans. Kiitz.

Melosira varians Ag.

Navicula ambigua.

Navicula borealis.

Navicula cryptocephala Kitz.
Navicula iridis.

Navicula fulva.

Navicula lanceolata Kiitz.
Navicula parva (Ehr).

Navicula pupula Kiitz.

Navicula pygmaea.

Navicula rhynchocephala Kiitz.
Navicula viridis (Nitz) Kiitz.
Nitzschia vermicularis Kiitz,
Odontidium elongatum (Ag) Kuntze.
Sphinctocystis librilis.

Stauroneis anceps.

Stauroneis phoenicenteron.
Surirella biseriata.

Surirella ovalis.

Surirella robusta.

Surirella spiralis.

Synedra acus Kiitz.

Synedra capitata.

Synedra radians Kiitz.

Synedra ulna Ehr.

Tabellaria fenestrata Kiitz.

Conjugatae

Station I Station II Station IIT Daily Hourly
Number of forms listed... 10 iI5} 13 5 5

Average number of indi-
viduals per cubic meter 121,653 331,687 420,463 26,827 931,948

The representation for this group is mainly desmid but there
were a few filamentous forms such as Spirogyra included occasionally.
These latter occurred in such small quantities, however, that they
had no appreciable volumetric effect and the count serves to show
their relative importance quite clearly. Including one form of
Spirogyra there are seven species of Conjugatae listed here which
will be given separate discussion. Even among the desmids the num-
ber of individuals was not great.

1920] Allen: Plankton of the San Joaquin River 63

DISCUSSION OF SPECIES

Closterium acerosum Ehrbg.

Station I Station II Station III Daily Hourly
LRN ENRON Ser aR Barer rece as 539 7,108 6,161 206 10,961

Identification uncertain. Losses through net probably large. Oc-
currence rare, irregular and in small numbers at Station I. Found
at almost all times of year at other stations. Maximum in September
at both. Evidently favored by higher temperatures.

Closterium acuminatum.

Identification doubtful. Recorded three times at Station II and
five times at Station ITI.

Closterium rostratum Ehrbg.

Station I Station II Station IIT Daily Hourly
JSS COR ee er aie 21,580 8,322 4,494 929 3,045

Identification satisfactory. Losses through net probably large.
Recorded only seven times at Station II, five times at Station III and
occurrence rare at Station I until late summer. Maximum at Station
IT in August. Distinctly a summer planktont. Apparently favored
by sewage.

Mougeotra sp.

Station I Station II Station IIT Daily Hourly
PA VIC AGC) Seancsctecssctcstevecacescnstscs 75,517 262,429 269,657 23,118 793,870

Identification of genus satisfactory. This was decidedly the most
abundant of the filamentous Conjugate. Rather prominent at all sta-
tions in July, August and September with maximum in last week of
August or first of September. Not found often or in large numbers at
other times. Favored by temperatures above 20° C. and somewhat
hindered in development by sewage. ;

Spirogyra protecta Wood.

Identification uncertain. Occurred once at Station I, five times
at Station II and nine times at Station III. Never in very large
numbers. So far as catches show it is unimportant in every way.

Staurastrum sp. A.

Station I Station II Station III Daily Hourly
Bot eA See teens 8,741 97,529 128,529 1,548 87,419

Genus certain. Species description not found in any literature
available. Only the more voluminous references at the University of

Average

64 University of California Publications in Zoology Vou. 22

California have been consulted, however. This Stawrastrum is the
most delicate and graceful of any ever observed by the present writer.
Losses through net probably very heavy. Occurrence as recorded at
Station I, small in numbers and seattered; May is the only month
yielding none. More abundant at other stations but missing in Jan-
uary and May. Maximum in September at all stations. This comes
after several weeks of strong development at Stations II and III.
Evidently favored by higher temperatures, 20° C. or above, but hin-
dered by sewage. Probably of considerable importance in summer.

Staurastrum spp.

Station I Station II Station III Daily Hourly
AVOTAGO) -.cecssccsescttwesscescsetenss 3,566 38,901 37,338 826 12,207

Probably three or more Stawrastrum are included under this head-
ing. There were a large number of different kinds found at various
times at different stations. All seem to be rather closely confined to
the warm season and to the water with least sewage.

The following forms of Conjugatae were recorded only once or
twice or were thought to have been recognized in living material.

Closterium gracile Breb.
Closterium lineatum Ehrbg. Once, III.

Closterium lunula Ehrbg. Once, IJ, and IIT.
Closterium obtusum Breb. Onee, II.
Cosmarium botrytis Menegh.

Cosmocladium saxonicum DeBy.
Didymoprium sp.

Docidium sp.

Sphaerozosma vertebratum Ralfs.

Spirogyra fluviatilis Hilse. Once, IT.
Spirogyra majuscula Kitz. Once, IT.
Spondylosium depressum Arch.

Staurastrum alternans Breb. Once, IIT.
Staurastrum cuspidatum Breb.

Staurastrum eustephanum Ehrbg. Once, I and Daily.
Staurastrum macrocercum.

Staurastrum vestitum Ralfs.

Xanthidium sp.

Zygnema sp.

CHLOROPHYLL BEARING ORGANISMS

So few flagellates were found that were clearly non-chlorophyll
bearing, there was so much difficulty in separating the two types,
and the characteristics of the Mastigophora so clearly resembled those

1920] Allen: Plankton of the San Joaquin River 65

of the algae, that it was finally decided to give a list of totals of
algae (except Bacteriaceae) plus Mastigophora under the heading of
chlorophyll bearing organisms (tables 1-5). This plan was also fol-
lowed with the graphs in plates 3 to 6. A separate list of algae is
given under headings of Total Phytoplanktonts (text table 1, p. 31),
but no graph was made for it as the slight apparent difference did not
seem to warrant it.

It will be noticed that this combination shows marked coherence
through the year. There is a rather prominent pulse in every month
through the first nine months at Stations I and II and in almost every
month at Station III. There is steady increase in numbers from May
to September at Stations II and III followed by a steady decline to
the end of the year, and at Station I the numbers were well maintained
from May to September with a steady decline following. The most
striking difference in the three stations concerns the maxima. The
maximum came in June at Station I and in September at the other
two. The June maximum at Station I was due, however, to the
enormous numbers of Cyclotella at that period. With Cyclotella ex-
erting less influence on the totals or entirely omitted, the general
features of occurrence look much the same at Station I as at the other
two stations.

The response to higher temperatures is quite noticeable at all sta-
tions, the larger numbers being especially characteristic of the time
from June to November when the temperature was usually near or
above 20° C. This, however, is also the time at which there was
least disturbance of the water.

The recurrent pulses were very striking and may be conveniently
illustrated by Station II where the dates and intervals ran as fol-
lows: January 19, three weeks to February 8, three weeks to March
1, four weeks to March 29, three weeks to April 19, four weeks to
May 17, three weeks to June 7, three weeks to June 28, five weeks to
August 2, three weeks to August 23, two weeks to September 6, five
weeks to October 11, seven weeks to December 6.

Fluctuations at Station II and III also showed a very close cor-
respondence with the volumetric record. This is probably because
the algae and Mastigophora furnished a large part of the volume at
those stations (plates 1, 4, 5). Such a conclusion is supported by
the fact that there is no such correspondence at Station I where the
Rotifera and Entomostraca furnish much of the volume (pl. 1, 3).

66 University of California Publications in Zoology |Vou. 22

PROTOZOA
Station I Station II Station IIT Daily Hourly
Number of forms recorded 75 53 59 26 34
Average number of indi-
viduals per cu. meter ....... 5,194,416 3,494,065 3,634,131 3,880,462 7,908,872

The number of forms recorded is 116 but that is certainly consid-
erably less than the real number of species. Identification was very
difficult, not only of species but of genera. Many species were indis-
tinguishable under conditions of counting and some that were re-
corded for a time were abandoned later when high power study
showed how great the error was. Distortion of preserved material
was a great factor affecting accuracy of counting of Protozoa. Even
such strikingly different species as the two stentors, (S. coeruleus and
S. niger) could not be separated with full confidence during the
count. For these reasons the list of Protozoa shows more often than
that of algae names which inelude several forms within rather ill
defined limits.

Notwithstanding the great diversity of characteristics shown by
several prominent protozoan planktonts, the distribution of totals
through the year at different stations deserves some attention. The
totals of non-flagellated Protozoa at all stations agree in that there is
light representation in January, February and December, with an
equally well defined heavy representation from May or July to mid-
November. Station I averages about 60 per cent higher on its totals
than either of the others but its maximum is only slightly greater.
The maximum for Station I falls on August 13 but it is almost
equalled by a similar pulse in November. The maximum for Station
II comes on October 4 and for Station IIT on August 15, but the latter
record is almost equalled by a further pulse on October 4. There is
then substantial agreernent of all stations in making the best showing
as to large numbers and continuity of numbers in late summer and
through autumn, when temperatures are rather high, the water quiet
and the organie content great.

The inclusion of the Mastigophora with the Protozoa almost de-
stroys the definiteness referred to above. Such a combination shows
at Station I a fairly well marked pulse in January, another in March
and another in April, followed by a steady increase up to the maxi-
mum on September 9. There were then two moderate pulses on the
decline, which was otherwise fairly steady to the end of the year. At

1920] Allen: Plankton of the San Joaquin River 67

Station IL there were prominent pulses in January, February,
March, May, July and October, while at Station III the prominent
pulses came in February, March, April, July, August, September and
October. It is thus apparent that the combined history is considera-
bly different at the different stations and that the inclusion of the
Mastigophora destroys the coherence of the Protozoa as a group. The
totals are given both with and without the Mastigophora in tables
1 to 5 and the reader may suit himself with the list of his preference.
See also Plates 12-14.

Mastigophora
Station I Station II Station III Daily Hourly
Number of forms recorded 33 30 31 20 20

Av. number per cu. meter.. 3,708,569 2,629,112 2,631,702 1,853,429 3,931,892
Almost all of the Mastigophora were too small to be retained by
the silk net to any great extent. This is probably the main reason for
the fact that the averages recorded are exceeded from twenty-five to
forty times by Kofoid’s averages (1908) in Illinois. It is certainly
true that other factors might be expected to operate, as mentioned
before in this paper, but this is so obviously sufficient in itself to
account for the difference that it seems useless to inquire further.

Mastigophora were present at all stations throughout the year,
although the numbers were quite small for the first few catches. This
may be partly due to the fact that the net used before January 15
was of slightly larger mesh than the regular number 25 which was
ready by that date. By far the larger proportion of the flagellates
came in the last six months, even December showing much more than
June. There were, however, two or three strong pulses in January
and February at all stations. Hence the general indication seems to
be that quiet water or even stagnation is about as important as tem-
perature in controlling production. The greater numbers at Station
I also indicate that. sewage is favorable to this group. The maximum
at Station I was reached in September, at Station II in October and
at Station III in November. These dates are largely due to Chromu-
lina sp., a form very unreliable for suggesting conclusions, both on
account of its small size and the uncertainty of identification.

The recurrent pulses of Mastigophora were not so distinct as they
were in the case of the total chlorophyll bearing organisms. The
semi-weekly collections at Station I seem to obscure them rather than
make them more distinct. At any rate the intervals vary from eleven
to forty days in a rather indefinite way. Indications at the other

68 University of California Publications in Zoology (Vou. 22

two stations are not much better. Evidently we have again too much
influence of Chromulina in the record. Since the only other flagel-
late showing very large numbers is T'rachelomonas, itself very small,
it seems hardly worth while to attempt any conclusions from net col-
lections.

DISCUSSION OF SPECIES

Ceratium hirundinella O. F. Mill.

Identification satisfactory. Loss through net probably very heavy.
Occurrence rare and in small numbers, four times at Station I in
September and October. Five times at Station II in June, July, Au-
gust and September. Three times at Station III in July, September
and October.

Cercomonas crassicauda Duj.

Identification satisfactory. Loss through net very heavy. Oceur-
rence rare and in small numbers. Recorded at Station I nine times
at wide intervals from July to the end of the year. Twice at Station
Il in July and September. Five times at Station III in June, August
and September.

Cercomonas sp.

Identification of genus doubtful. Recorded seven times at Station
I in August and September, and once at Station III.

Chlamydomonas sp.

Identification of genus doubtful. Recorded eight times at Station
I from July to December, five times at Station II from May to October
and twice at Station III in February and May.

Chromulina spp.

Station I Station II Station IIT Daily Hourly
PAS CNEL Oy comes secre eeceenepeercecs 2,760,969 2,225,384 2,241,982 4,136,123 30,256,512

Identification uncertain. May include various minute genera not
readily distinguished while counting. Percentage retained by net
surely very small. Found in every month at all stations but occa-
sionally not recorded in the first half year. Constantly present after
July. Maximum at Station I on September 13, Station II on Octo-
ber 26, and Station III on November 22. Evidently favored by warm
and quiet water and not much affected by sewage.

1920] Allen: Plankton of the San Joaquin River 69

Cryptomonas sp.

Identification doubtful. May be confused with some other forms.
Loss through net heavy. Reeorded at Station I in considerable num-
bers in latter part of year. Only once at Station II and four times
at Station III. Distinctly favored by sewage and low temperature
but relatively indifferent to quiet water by this showing, which agrees
pretty well with Kofoid’s findings (1908) in Illinois.

Dinobryon sertularia Ehrbg.

Station I Station II Station IIT Daily Hourly
PAV CLAS @: Uaccrcecctceiassnsecscnsceececcen) cscasesenszesecs 11,481 DOD Sie cesernceee estes tan ceceeeceeea

Identification of species frequently uncertain. Loss through net
probably large. Occurrence rare at Station I and in small numbers
of colonies at that. Recorded eleven times at Station II in four, well
marked groups at the last of March and May, first half of June and
through most of November. Maximum in May and June. Recorded
frequently at Station III from March to July and again in November.
Absent at other times. Favored by cooler water or flood time and
hindered by sewage. Although the numbers here were small the
distribution resembles that recorded for Illinois most remarkably. On
the present showing it cannot be regarded as a very important plank-
tont here. While not followed very far, the general impression given
by the condition of the colonies here leads to support of Kofoid’s
contention (1908) that the synonymy of this species has been need-
lessly extended and that all the variant forms might be included
under one species name with advantage.

Eudorina elegans Ehrbg.

Station I Station II Station IIT Daily Hourly
PACT OOO) EE tae ees siase eetcceasseees 11,277 84,275 71,776 9,351 376,375

Identification usually certain. Found throughout the year at
Stations II and III with only six scattered periods of absence at each.
Numbers much smaller and absences more apparent at Station I
where it was only twice recorded in May, entirely absent in August
and most of September, last half of October and first half of Novem-
ber. Evidently deleted by sewage. Maximum in October at this
station, on August 9 at Station If and III. Contrary to the Illinois
record the period of greatest abundance in our river is in the warm-
est season and almost at greatest stagnation. The complete absence
at Station I at this time, however, may throw some light on the Illinois
situation. Hither the sewage is more injurious to this organism in

70 University of California Publications in Zoology (VoL. 22

warmer weather or else its enemies multiply faster under such con-
ditions and so keep it down. The substantial agreement of Stations
IT and III upon such a point in opposition to Station I makes it al-
most certain that sewage or organie content is in some way a more
influential factor than temperature in the warmer season. There
are some indications of recurrent pulses at all stations but they cannct
be readily followed through the year. Parasitized colonies were fre-
quently found, especially through the warm season. Hudorina is evi-
dently a more important planktont here than in Illinois except at
Station I where it is about the same.

One experience in collecting at Station I gives some interesting
evidence as to the occurrence of swarms. The regular collection was
taken near shore from the boat landing, one morning about 8 o’clock.
On examination of the living material under the microscope after
reaching home it was found to contain unusual quantities of Hudorina.
It seemed a favorable time to make a special collection to send to
Professor Kofoid so another trip was made to the same spot and
hauls taken as nearly as possible in the same way as before. Although
there had been a time interval of less than two hours seareely any
Eudorina could be found anywhere about. Weather conditions had
not changed and there had been no great disturbance of the water by
boats as it was on a Sunday morning when the traffie was light.

Euglena deses Ehrbg.
Identification satisfactory. Loss through net heavy. Recorded at
Station I five times and once at Station IT.

Euglena viridis Ehrbg.

Station I Station II Station IIT Daily Hourly
PAV. GTO esas pet cearee eee 51,693 11,782 13,592 306,464 28,975

Identification satisfactory. Probably very small percentage re-
tained by net. Oceurs mainly in summer and early fall at all sta-
tions. Maximum in July at Station I and III, June at Station IT.
Apparently favored by sewage, quiet water and temperatures above
20° C. Information from silk net catches not reliable beyond this.

Hemidinium nasutum St.

Station I Station II Station IIT Daily Hourly
PNW CVV RG) chase steecer eee crecs cea 535,079 28,482 26,967 228,971 293,432

Identification doubtful. Very small percentage retained by net.
Reeorded only in last half of year at all stations, possibly because not

1920] Allen: Plankton of the San Joaquin River Al

definitely distinguished before. Wery few at any station after mid-
October. Far more numerous at Station I than at either of the others.
Certainly favored by temperatures near or above 20° C. by quiet
water and by sewage.

Mallomonas sp.
Identification of genus certain. Recorded three times at Stations
I and III in small numbers.

Pandorina morum Bory.

Station I Station II Station IIT Daily Hourly
WASVICYAIPO” fopate shot eestet cass snacnaeatc 2,752 16,804 15,457 103 102,150

Identification satisfactory in most cases. May sometimes include
young colonies of Hudorina or Pleodorina. Probably some loss through
net. Occurrence at Station I frequent in small numbers through first
three months, after that at irregular intervals usually several weeks
apart. Fewest in warmer months. Maximum on March 26. At Sta-
tion II most constant occurrence was through February and March in
moderate numbers. Maximum of 105,792 reached in each of the four
months of June, July, August and September. At Station III fairly
constant in February and March, November and December. Records
grouped at irregular intervals between. Maximum in May. Although
the records differ strangely at the three stations it seems fair to infer
that sewage is deterrent, especially during stagnation but that warmer
waters are favorable if stagnation could be avoided. It is possible,
however, that the organism was not captured so constantly in warmer
waters because those were the quiet waters, hence there were no cur-
rents to mix if through the whole body of water. If this be true it is

ce

easy to see that the net might at one time traverse a ‘‘swarm’’ of

the organisms but miss it entirely at another time.

Peridinium cinctum Ehrbg.

Station I Station II Station IIT Daily Hourly
EAST OIEIERE: cent onseetbens moceecepeececsc 34,262 5,209 18,732 111,324 12,207

Identification uncertain. Probably very small percentage retained
by net. Occurrence rare in first half year at all stations. Recorded
only six times at Station II and seven times at Station III. Evidently
favored by sewage, since it occurred frequently in rather large num-
bers at Station I from late June to late November. Maximum appar-
ently in July with most consistent record in September. Evidently
favored also by temperature of 20° C. or over, and by quiet water.

72 University of California Publications in Zoology {Vou 22

Peridinium sp.
Identification of genus satisfactory. Species different from P.

cinctum but not placed. Recorded four times at Station II three
times at Station ITI.

Phacus pleuronectes Ntz.

Station I Station II Station III Daily Hourly
FASVOY ALC <eaceccccccscrcneocsensastencare 25,375 1,048 WGP Meese caters | corte ce

Identification questionable. Loss through net probably very heavy.
Occurrence twice at Station II and thrice at Station III in small num-
bers. Recorded with only five exceptions at Station I through last
three months of year. May have been overlooked before. Kofoid
(1908) designates this genus and this species as a summer planktont.
The failure of the record here to support fully this view may be due
to small size and consequent inaccuracy with silk net catches.

Platydorina caudata Kofoid.

Station I Station II Station IIT Daily Hourly
BASU OY, O) eeese reer rct ceased aan cenenan= 431 3,569 5,020 206 48,290

Identification positive. Loss through net considerable. Occur-
rence quite distinctly limited both by temperature and sewage. Re-
corded only six times at Station I, all at variable intervals from Au-
gust 2 to November 1 and in very small numbers. Nine occurrences,
mainly in August and September at each of the other stations. No case
of occurrence in temperature less than 17° C. Maximum at Station
I on September 2, Stations II and III on September 13. Considering
the small numbers and the short period of occurrence, the similarity
of occurrence at the three stations is most remarkable. All stages of
development were found and special collections were made for Pro-
fessor Kofoid in order that he might study some features of develop-
ment.

Pleodorina californica Shaw.

Station I Station II Station IIT Daily Hourly
INS GTEN GS) eee eee ere 123 21,231 6,282 413 67,751

Identification certain. Probably most of the matured colonies
were retained by the net. Recorded only twice (in August) at Sta-
tion I. Evidently strong sewage is deterrent though Kofoid (1908)
mentions sewage as probably a factor leading to larger numbers in
1897 than in 1898. Station II showed the only consistent develop-
ment of this organism. After being recorded in mid-June it was not
found until three weeks later when it began an eight weeks period of

1920] Allen: Plankton of the San Joaquin River 73

steady increase to a maximum on August 31, followed by a three
weeks decline, after which there were three isolated records. Station
III showed no distinct maximum but the nine catches were distributed
over about the same period from July to mid-November. It seems
clear enough then that too much organic matter, and possibly too
great stagnation, is detrimental and that the optimum temperature
is above 20° C.

Pleodorina illinoisensis Kofoid.

Identification uncertain. Probably some loss through net. Re-
corded once at Station I, twice at Station II and four times at Station
III, all in small numbers. A puzzling thing about this form is that
when examining fresh catches in 1913 the writer was sure he found
it frequently and in considerable numbers. Hence he was somewhat
surprised at not finding it readily while counting. About the only
conclusion possible is that it is very hard to distinguish this form
from Eudorina elegans in preserved material. Chodat (1902) and
others would doubtless say that this fact supports their view that P.
illinoisensis is only a stage of development of Eudorina.

Pteromonas sp.

Identification probable. Loss through net heavy. Occurrence
irregular and rare. Recorded ten times at Station I between June
21 and October 8, three times at Station II and twice at Station IIT.
Apparently favored by sewage, stagnation and higher temperatures.

Spondylomorum quaternarium Ehrbe.
Identification certain. Loss through net heavy. Occurrence very
rare in small numbers. Recorded twice at Station I, once at Station IT.

Synura wvella Ehrbg.

Station I Station II Station III Daily Hourly
PALV OTA LO! ccccse asc S noes oe ceecsecec 6,415 30 4,462 5,222

Identification uncertain. Colonies only counted. Loss through
net probably very heavy. Occurrence greatest at Station I but at
wide intervals there. Numbers recorded usually rather small. From
our records it seems to do best at about 20° C. Maximum at Station
Tin August. Also evidently favored by sewage and stagnation, since
it is recorded only once at Station II and five times at Station III.
Certainly much less important than in Illinois, even with full allow-
ance for escape through the net.

74 University of California Publications in. Zoology (Vou. 22
gy

Trachelomonas euchlora Lemm.

Station I Station II Station IIT Daily Hourly
ASOD By cesnereseas totemcsoeene erences 14,295 21,739 30,180 7,032 56,965

Identification uncertain. Small percentage retained by net. Found
frequently in first half year at all stations. Rare in second half year.
Warmer waters, sewage and stagnation seem to be deterrent, since
numbers were smallest at Station I and during the period from June
to October.

Trachelomonas volgensis Lemm.

Identification probable. Loss through net very heavy. Recorded
five times near last of year at Station II and six times at Station III.

Trachelomonas volvocina Ehrbg.

Station I Station II Station III Daily Hourly
PAOLA Oy oeccc se oceeeeecsecte retro 268,091 184,297 180,692 179,473 512,684

Identification uncertain. Loss through net very heavy. Recorded
in every month at all stations. Maximum at Station I on August 20,
at Station II on September 13, and at Station III on August 31.
While a number of minor pulses are readily distinguishable at all
stations, the percentage of loss is too uncertain to encourage conclu-
sions. The maxima of the three stations coming so close together lead
to the idea that temperature is an important factor for this form
and that it does best above 20° C. The difference in averages listed
above supports the view that sewage is beneficial and this is strength-
ened by the fact that several catches at Station I exceed the maxima
at Station II and III. Stagnation seems favorable at all stations.

Volvox aureus Ehrbg.
Identification satisfactory. Recorded only at Station II, five
times in August and September.

Volvox globator L.
Identification satisfactory. Recorded only at Station III twice, in
September and December.
The following forms of Mastigophora were recorded only once or
twice, or else they were thought.to be present in fresh material:
Anthophysa sp. Once, I and Daily.
Chilomonas paramoecium Ehrbg.
Dinema sp. Once, III.
Diplosiga sp. All stations. Not counted because too small.
Diplosigopsis entzi France. Once, II.

Euglena acutissima Lemm.
Gonium pectorale O. F. M. Once, II and III and Hourly.

1920] Allen: Plankton of the San Joaquin River 75

Gymnodinium sp.

Hyalobryon sp.

Mastigamoeba sp. Once, Station I, Station II and Hourly.

Oikomonas sp. Once, Station I. =

Phacus longicauda Duj. Station I.

Salpingoeca sp.

Synerypta sp. Once, Station IT and III.

Uroglena volvox. Once, Station III and Hourly.

Rhizopoda
‘ Station I Station II Station III Daily Hourly

Number of forms recorded 13 14 17 if 9

Average number of indi-
viduals per cubic meter 167,328 150,817 288,365 101,802 396,950

Rhizopoda, according to our records are from five to ten times
as numerous as in Illinois. This is probably erroneous, however,
since Difflugia contributes mainly to this showing and the Difflugia
count includes an unknown percentage of Tintinnidium. Conceding
this error to be very large, it still seems safe to say that the Rhizopeda
were at least as important as in Illinois where Kofoid (1908) gives
them a high rank because they are bottom lving forms, actually
present in far greater numbers than the eatch of floating forms could
possibly indicate. This adventitious character is just. as strongly
marked here as there, since all the recorded forms are irregular in
distribution and erratic in occurrence. The group as a whole con-
tributes most during the warmer season. This might be expected as
a result of greater activity of the animals rendering them more liable
to dislodgment. Larger numbers produced would also mean larger
numbers dislodged. Heavy food supply would also account for it in
part because, as Kofoid (1908) says, it means greater oil and gas
production in the body of the animal thus reducing the specific

gravity.
DISCUSSION OF SPECIES

Amoeba proteus Rosel.

Station I Station II Station III Daily Hourly
Average sosesieenecere eterna eae 2,782 14,487 3,645 206 61,034

Identification uncertain. Probably includes several species. Amoeba
proteus was the large form most frequently observed and so the name
is used as being probably most frequently correct. Occurrence rather
irregular at all seasons of the year. All stations agree in showing the
largest numbers at about the height of the warm season, i.e., in Au-
gust at Stations I and II and September at Station III. All show
only very small numbers in cold weather. Larger numbers at Station

76 University of California Publications in Zoology (Vou. 22

II may be due not so much to favorable effect of clean water as to the
slight flow in the river tending to greater dislodgment.

Amoeba radiosa Duj.

Station I Station II Station III Daily Hourly
PNAC Ed tt ie ee 18,202 11,528 17,852 206 12,209

Identification satisfactory. Losses through net probably great.
Although Kofoid (1908) counts A. radiosa with A. proteus, it is given
separate listing here because it was the one form that seemed to be
always clearly recognizable under conditions of counting. Either
singly or combined the two forms were decidedly more numerous than
the combination was in Illinois, and this is true of all stations. A. rad-
iosa was not recorded at any station until the last of April. It devel-
oped a small pulse at Station I in May, disappeared entirely in July
and August but reappeared in considerable strength in September.
The maximum came in a strong abrupt pulse in late October after
which the form disappeared again showing only two small records in
the rest of the year. At Station II there were two occurrences in April
and May, one (the maximum) in September and a small series of four
records in October and November. At Station III there were scat-
tered records from July to a September maximum, a small group in
October and November and one eateh in December. In spite of con-
siderable differences at the three stations the record shows a rather
definite preference for water a little below the maximum temperature.
The larger numbers at Station I indicate a preference for sewage.
An almost equal number at Station III warns against too much con-
fidence in such a conclusion, however.

Arcella vulgaris Khrbg.

Station I Station II Station IIT Daily Hourly
AVOLAGO! 52.ccccccceccecctecccaeaeaxte- 238 523 1,790 103) 2sskee

Identification of species uncertain. Probably includes three or
four species. Certainly there were marked differences in shells found.
Not very important in our plankton so far as our records show. Oc-
curred only seven times at widely separated intervals at Station ie
four times in April and June at Station II, and six times at wide
intervals at Station III. Numbers always rather small. Is known
to be very abundant in ditches near Stockton. Clearly adventitious.

Cyphoderia ampulla Leidy.

Identification probable. Recorded five times at Station II, and
four times at Station III in rather small numbers and at wide inter-
vals. Clearly adventitious.

-~]
-]

1920] Allen: Plankton of the San Joaquin River

Difflugia corona Wallich.

Identification uncertain. Recorded three times at Station I, six
times at Station II and twice at Station III, always in small numbers.

Difflugia pyriformis Py.

StationI Station II Station IIT Daily Hourly
Avera req esters cue 76,692 51,957 43,846 71,508 28,483

Identification uncertain. Surely ineludes several other species
certainly includes some Codonella and Tintinnidium which could not
be readily distinguished while counting. This was especially true up
to August before the presence of Tintinnidium and Codonella was
noticed. In view of this error the record for Difflugia cannot be re-
garded as trustworthy. The variations in form are bewildering at
best. As the record stands, the maximum seems to fall in June at all
stations and Station I shows the largest numbers.

Hyalodiscus sp. f : , é
Station I Station II Station IIT Daily Hourly
PAC CL AO ON © mess corse ce ears saceececsoes 26,286 15,566 De BUS. eet eeces 144,447

Identification very doubtful. This form was not recorded until
late in the season because it was small and hard to diagnose. It was
finally decided to record it simply for the purpose of calling atten-
tion to considerable numbers of an organism frequently occurring
which could not be definitely designated. The condition of the rec-
ords does not warrant conclusions.

Microgromia socialis H. and L.
Station I Station II Station III Daily Hourly

PACT ADC! 7acn2csaescsscacetesccseseneveres 23,280 56,487 72,004 15,976 61,034

Identification uncertain. Probably heavy loss through net. Oc-
currence at Station I in every month except January and December.
Found mainly at the other stations in July, August, September and
October. Evidently favored by warm weather and deterred by
sewage.

The following forms were recorded only once or twice, or were
thought to be present in fresh material :

Amoeba verrucosa Ehrbg. Once, II and III.

Difflugia acuminata Ehrbg. Once, II and III.

Difflugia globulosa Duj. Once, I and twice at III.
Euglypha alveolata Duj.

Hyalosphenia cuneata St. Twice, I.

Hyalosphenia papilio Leidy. Twice, I, once, II and IIT.
Nebela collaris Leidy. Once, III.

Pseudodifflugia gracilis Schlumbg. Once, IIT.

Quadrula symmetrica F. E. Sch. Once, III and daily.
Trinema enchelys Ehrbg. Once, III.

78 University of California Publications in Zoology [Vow 22

Heliozoa
Station I Station II Station IIT Daily Hourly
Number of forms recorded 8 6 10 4 4

Individuals per cu. meter.. 370,995 257,232 274,580 619,156 441,478

While there were only a few species of Heliozoa recorded the
numbers of some of the smaller forms were quite large and so make
the group somewhat important. The extreme fragility under manipu-
lation makes detailed examination somewhat untrustworthy in results
and also invalidates the count more than in the other groups. Never-
theless the following records seem to be fairly satisfactory. Through
some error in copying early lists, Nuclearia and Vampyrella were in-
eluded with Rhizopoda. The numbers do not seriously change the
totals in the two groups, however; the totals for Heliozoa have been
left short by that much and the totals for Rhizopods show a corre-
sponding excess.

DIscussION OF SPECIES

Heterophrys focket Arch.
Station I Station II Station IIT Daily Hourly
PAV OT AIS Gs Fedo ne cea. ssctescrex emote 24,459 139,328 98,532 55,170 207,538

Identification uncertain. May include other species or other
genera at times. Thought to be usually correct. Not recorded at any
station before July. Not present at any after October. One of the
most definitely limited organisms on our records. Limited to a period
of about sixteen weeks with a peculiar break in the middle (last of
August). This is a period in which the temperature was almost con-
stantly above 20° C. Maximum numbers on August 2 at Station I,
October 4, at Stations II and III. Smaller numbers at Station I in-
dicate deterrent action of sewage.

Heterophrys sp.
Probably not deserving separate listing though this fact was not
discovered until too late to change easily. °

Nuclearia simplex Cienk.

Station I Station II Station III Daily Hourly
PANY. OX AGG iapecaseeentore eae eeeeecaors 7,020 338 15,871 206 44,758

Identification uncertain. No records until late in the season,
partly because overlooked until October, partly because of indecision
as to advisability of recording. It was finally decided that some indi-
cation of the presence of an organism possibly belonging under this
species name was desirable. No conclusions can safely be drawn as
to distribution, however.

1920] Allen: Plankton of the San Joaquin River 79

Raphidiophrys elegans H. & L.
Station I Station II Station III Daily Hourly

PANY CLAN. C) een teesatetyccxecscvecacsseete 309,635 79,467 107,739 532,371 20,3845

Identification probable. First recorded in April at Station I and
Station III, in March at Station II. Constant in occurrence at
Station I through June, July, August and November. Irregular at
other times. Irregular at both the other stations except for a period
through August and early September at Station II, late June and
July at Station III. Evidently favored by higher temperatures and
sewage, not so much by stagnation. From these records, seems to be a
rather important constituent of our plankton. This is somewhat dif-
ferent from the condition at Illinois where it appeared only as a con-
stituent of back waters.

The following forms were recorded only once or twice or were
thought to be present in living material.

Actinosphaerium eichornii Ehrbg. Once, I and III.

Diplocystis sp.
Vampyrella sp. Once, III.

Ciliata
3 Station I Station II Station IIT Daily Hourly
Number of forms recorded 32 22 25 9 10
Number of individuals
per cubicemeter sess 946,762 447,909 431,445 1,306,075 3,136,583

Identification of ciliates was about as unsatisfactory as was that
of the Rhizopoda and Heliozoa. This was due partly to distortion of
preserved specimens and partly to small size. It is probable, how-
ever, that totals for the group are fairly accurate.

Members of the group were always found throughout the year,
except for the first three and two collections at the first of the year
at Stations II and III respectively. Unfortunately no general con-
clusions can be stated with full confidence from the totals of Protozoa
because Vorticella sp. is too largely responsible for them. This was
because Vorticella sp. was used as a sort of catchall for a miscellaneous
assemblage of organisms which could not be readily distinguished
under conditions of counting. Most of these were clearly Vorticella
(nearly all of the short stem type) but some craspemonad flagellates
and the like were undoubtedly counted in at times. In spite of these
defects in the record, there is some reason for thinking that the group
as a whole develops best in sewage water and in the higher tempera-
tures with rather stable conditions. Since this does not agree very

80 University of California Publications in Zoology [Vou 22

well with Kofoid’s (1908) Illinois results and since the net error is
undoubtedly great, too much importance must not be attached to
such a suggestion.

Whatever the truth may be concerning their distribution there
is no question that the Ciliata exert a very marked influence amongst
loeal planktonts, especially in Stockton Channel. The larger Ciliata
are quite conspicuous in the eatches there in the colder months.

DISCUSSION OF SPECIES

Askenasia elegans Bloch.

Identification probable. Recorded only at Station I four times in
small numbers. Thought to have been positively recognized in fresh
material, however.

Chilodon sp.

Identification doubtful. Recorded four times at Station I and
twice at Station IT in small numbers.

Coleps hirtus Ehrbg.
Station I Station II Station III Daily Hourly

DENN STEN REY eenesres ce sener re s ees 7,338 3,052 BAO) at Soon

Identification certain. Loss through net heavy. Probably also
overlooked in counting sometimes. Recorded ten times at Station I,
five of which came in December. Recorded twice at Station II and
once at Station III. Evidently favored by sewage and probably by
temperature below 15° C.

Colpoda sp.
Identification very doubtful. Recorded at Station I five times in
very small numbers, once at Stations II and III.

Cyclidium sp.
Station I Station IT Station III Daily Hourly
AION AG Cit Mrerce sacra ecacecnsanraces 29,530 10,234 Gi286 i eee 24,414
Identification unsatisfactory. Referred to this genus purely on
general resemblance to figures in reference books. No undulating
membrane was visible under conditions of counting. Apparently a
warm water form favored by sewage. Small percentage retained by
net.

1920] Allen: Plankton of the San Joaquin River 81

Didinium nasutum.

Average at Station I, 1,636.

Identification positive. Recorded sixteen times at Station I at
irregular intervals January to April and in November. Only once
at Station II and twice at Station III. Distinctly a cold water form.
Probably heavy loss through net.

Euplotes patella Ehrbg.
Station I Station II Station III Daily Hourly
PAN OT AO Gn ates seve eore eacecsceszeceeee 38,100 7,350 BHO G Sheree cece eats erent

Identification of species fairly certain. Recorded in first three and
four months and the last two months at all stations. Far more numer-
ous at Station I. Distinetly favored by sewage and low temperatures.
Spring maximum on March 19 at Station I at 14.5° C. Fall maxi-
mum on November 12, at 17.5° C. Disappearance in April at 20° C.,
reappearance in October at 19° C.

Euplotes sp.

Average at Station I, 3,567.

Recorded only twelve times at Station I (February 8—April 5),
twice at Station II and three times at Station III. Showed same
tendencies of distribution as preceding species. Probably variety of
same.

Halteria grandinella O. F. Mill.

Station I Station IT Station IIT Daily Hourly
PAV CT TC) sscsbe so ascsenascseesaecasecesee 3; 390\) eeceeeees. 126 206 12,207

Identification probable. Loss through net heavy. Recorded sixteen
times in first three months and five times in the last three months at
Station I, only five times at Station III. Apparently adventitious
and not of much consequence here.

Hastatella radians Erlanger.

Station I Station IT Station III Daily Hourly
UNS GCE ee cr a eee 2,245 32 UOT (acess ee arenes

Identification positive. Probably very small percentage retained
by net. Recorded fourteen times at Station I, once at Station IT and
twice at Station III, in February, March, April and December. Dis-
tinetly a cold water form and almost as distinctly favored by sewage.
Notwithstanding its small size this form is so distinct in appearance
and so little deformed by preservation that the count is unusually
trustworthy.

82 University of California Publications in Zoology (Vou. 22

Hlolophrya'sp. Station I Station II Station III Daily Hourly
Average, sete ees 109,113 76,816 103,778 140,641 870,497

Identification very doubtful. This generie name was used as a
eatchall for a number of forms that might be referred to it without
too great stretch of possibilities. They were usually too much de-
formed in preservation to give any definite clue to affinities. About all
that can be safely said is that the assemblage is favored by warmer
waters and stagnation, probably also by sewage.

Paramoecium aurelia O. F. Mill.
Station I Station II Station IIT Daily Hourly
MAVOTA QO) creercce cee cues eieeteecccuce 10,931 1,415 OAL | Aoi nctere pe ee

Identification satisfactory. Loss through net probably heavy. Oc-
currence almost entirely limited to first two and last two months of
the year. Hence distinctly a cold water form. Record at Station I
fairly constant in periods mentioned, with a maximum in December.
Numbers small and eatches rare at Station II and III. Evidently
does best in sewage, probably on account of quantities of bacteria for
food.

Paramoecium bursaria Focke.
Station I Station II Station IIT Daily Hourly
AV OREO eefen eee ores eeeeeseee 9,785 4,254 vIn ht ee een pe Ae oe a

Identification uncertain. Probably should be ineluded with P.
aurelia though there seemed to be some difference. Shows practically
same characteristics of distribution as the former species.

Paramoecium caudatum Ehrbg.

Identification satisfactory. Although a few specimens of this
type were found six times at Station I and once at Station ITI, it was
probably not- worth while to attempt separation. They are too few
to signify much.

Pleuronema sp. : : ; :
Station I Station II Station IIT Daily Hourly
SASVOT ADO) oeas-clescs cece ne ccte cectess 5,402 8,052 WG!» \oszcokedence cee aa tenteeeean

Identification doubtful. Reeorded thus as nearest possibility.
Records indicate preference for sewage and cold water.
Prorodon sp. : ; ;
Station I Station II Station IIT Daily Hourly
Average 7,379 677 4,243 206 492
Identification uncertain. Occurrence almost entirely confined to
first three months and last three months of the year, thus indicating
the favorable influence of cold weather. Larger numbers at Station

I were probably due to sewage.

1920] Allen: Plankton of the San Joaquin River 83

Stentor coeruleus Ehrbg.

Station I Station II Station III Daily Hourly
PAN CLAG Oi tletse et cceat eae nena 8,141 123 Alig, eee as 492

Identification usually satisfactory. Under conditions of counting
probably some confusion with S. niger and perhaps another species.
This was because distortion in preservation made it almost impossible
to use any distinction except size in many cases, hence a small J.
coeruleus might be mistaken for S. niger, or a large specimen of the
latter might be mistaken for the former. Generally, however, the
stouter body of S. coeruleus showed plainly enough to make it fairly
certain. Occurrence was almost confined to first four months and
December. Only two catches were recorded at Station II and three
at Station III. Clearly a cold water form almost limited to sewage
or at least to water with heavy organic content. Maximum occurred
in December at Station I, although the catches were fairly constant
over a period of four months from the first of the year. The maxi- ~
mum for this early period was in January. Since it is absent at
periods of greatest stagnation, this planktont is evidently more influ-
enced by temperature than by that factor. The most favorable tem-
perature seems to be at about 10° C. since the maxima just mentioned
come at about that condition.

Stentor niger Ehrbg.

Station I Station II Station IIT Daily Hourly
BAS OTAGO racecar ete secs: lecesadsace 42,691 739 Sill | see 472

Identification satisfactory. Probably some loss through net. Also
considerable loss of this and the preceding form through clinging to
net, utensils, ete. This form was first recorded as S. roeselii on account
of the nucleus, but the delicacy and grace of form together with
smoky color seem so strongly characteristic that it has finally been
referred to S. niger. The decision to make the change was mainly due
to Professor Kofoid’s statement that nuclear characters are very
unstable in this genus. They cannot be determined at least while
counting.

Occurrence at Station I runs later in spring and begins earlier in
fall than that of S. coeruleus. The numbers are very noticeably
greater in the fresh material while the animals are active. The Jan-
uary and December maxima fall on the same dates as those of J.
coeruleus but there are strong pulses in April and May by way of
contrast. It seems safe to say then that both species have about the
same optimum but that S. niger is able to endure a slightly higher
temperature (20° C.) and that it is less disturbed by flood conditions.

84 University of California Publications in Zoology (Vou. 22

Tintinnidium fluviatile St.

Station I Station II Station IIT Daily Hourly
MAVIOTEQLO! <ezvecntsncresdcesueneerescccees 17,333 3,359 8,642 7,341 323,479

Identification uncertain. Loss through net probably heavy. For
some reason (probably because intent on Difflugia) the writer entirely
overlooked this form and that of Codonella until attention was forci-
bly attracted by some living material in 1914. This was after the
count had progressed almost through the first seven months of 1913,
hence it was too late to rectify by recounting. It was also impossible
at that late date to distinguish the three forms readily in preserved
material. Undoubtedly some Codonella and.a few Difflugia are in-
cluded under the present head. It is also probable that Difflugia in-
eludes some of both Tintinnidiwm and Codonella even after an attempt
was made to differentiate them. Codonella was not successfully dis-
tinguished at all. The count as it stands yields very imperfect results.
It appears certain, however, that Tintinnidiwm does best in heavy
sewage. Since the river shows least of this species it is also probable
that quiet water is favorable. So far as the evidence goes, it seems
that higher temperatures are best.

Trichodina pediculus Ehrbg.

Average at Station I, 631.

Identification probable. Loss through net probably heavy. Oceur-
rence at Station I almost entirely in first three and last three months.
Recorded only once at Stations II and III. Small numbers every-
where. Surely a cold water form favored by sewage. Adventitious.

Vorticella longifilum Ehrbg.

Station I Station II Station ITI Daily Hourly
LAST OREY GG) Seton erin dete cere gore 13,991 2,588 3,612 413

Identification doubtful. Count ineludes all individuals with very
long and slender stalks. None were ever found attached to anything.
Loss through net probably very heavy. Occurrence at Station I
mainly in last three months. Catches in small numbers and at widely
separated and irregular intervals at other times and other stations.

Evidently a cold water form doing best in sewage and quiet waters.

Vorticella sp.
Station I Station II Station IIT Daily Hourly

623,067 274,328 800,528 1,153,087 1,797,514

Identification uncertain. Probably includes several species of
short stemmed Vorticella and some craspemonad flagellates attached
to various objects.

Average ...

1920] Allen: Plankton of the San Joaquin River 85

Those taken to be most typical of this miscellaneous assemblage
were found on the bodies and appendages of Entomostraca, especially
Cyclops. Most of these were large enough to be fairly accurately
counted. In view of the miscellaneous character of the forms in-
cluded, it is undesirable to draw definite conclusions. There is, how-
ever, a clear suggestion of preference for sewage and quiet water.
Higher temperatures are also distinetly favorable for the assemblage
and this is in marked contrast to nearly all the other ciliates.

The following forms were recorded only once or twice or else
were thought to be observed in fresh material.

Aspidisca sp.

Bursaria sp. Twice I, once, III.
Carchesium sp.

Climacostomum virens St.
Condylostoma vorticella Ehrbg.
Didinium balbianii Btschli.
Enchelys sp. Twice, I, once, III.
Epistylis sp. Twice, II.
Frontonia sp. Twice, I, once, III.
Gastrostyla sp.

Glaucoma sp. Onee, I.
Laerymaria sp.

Loxophyllum sp. Twice, I.
Mesodinium acarus St.

Pyxidium cothurnoides Kent.
Rhabdostyla brevipes Cl. & L. Once, I.
Spirostomum sp.

Trachelius ovum Ehrbg. Twice, I.
Urocentrum turbo Ehrbg.

Suctoria
Station I Station II Station IIT Daily Hourly
Number of forms recorded 3 3 3 ae 1
Number of indi-
viduals per cubic meter 762 8,995 S030) Soe oe 1,969

Only three forms were recorded from this group and they oce-
curred at all three stations but mainly in the last three or four months
of the year. In no ease were the numbers very large. While genera
could not be identified with much confidence, it yet seemed clear that
the forms recorded were Suctoria and that the generic designation
was probable. Inasmuch as none of the three forms appeared to be
a true planktont and the numbers were few, it seems hardly neces-
sary to attempt detailed discussion. The most notable suggestion
that can be made is that sewage seems unfavorable to all three forms.
The following are the three forms recorded. See tables 1-5.

Acineta sp. Podophrya sp. Sphaerophrya sp.

86 University of California Publications in Zoology (Vou. 22

ROTIFERA
Plates 3-6 and 15-17.

Station I Station II Station IIT Daily Hourly
Number of forms recorded.. 55 43, 39 30 34
Individuals per cu. meter.. 4,842,320 883,510 1,302,609 5,443,643 5,681,372

Eggs 31% Eggs 45% Eggs 34% Eggs 29% Eggs 34%

These averages are made from records which include males, fe-
males, eggs attached, a few records of free eggs, winter eggs, male
eggs and parasitized individuals. Further distinctions were not ad-
visable because of inability to carry them through the count with
accuracy.

Rotifera were found in every collection through the whole year at
all stations. Only twice in the whole year did the numbers fall
below 75,000 per eubie meter at Stations II and III, and at no time
was a smaller number than 200,000 recorded at Station I. This makes
a remarkably consistent showing, especially by way of contrast with
Illinois conditions as found by Kofoid (1908). This consistency is
even more striking than are the distinctly larger numbers found here
at all stations. Both features are evidently due to the peculiar cli-
matic conditions of this region. There is agreement with Illinois
records in the fact that minimum production occurred in winter and
the maximum in warmer weather, though much later there than at
Station I. There is a difference in that the fluctuations were less
extreme here, and that maxima occurred in November at Stations II
and III.

Recurrent pulses were fairly well marked at all stations though
the intervals were quite variable. These pulses were not coincident
with those of any other group. The maximum number of Rotifera
did not correspond in time with the maximum mass production of
plankton at any station nor did it agree with any other group.

This group affords another illustration of a ease in which a single
genus exerts a remarkable influence on the whole group, the late
maximum in November at Stations II and III being due to Keratella.
Since, however, this same genus is largely responsible for throwing
the Illinois maximum into May, perhaps those records and ours can
be compared with some fairness.

Catches of 1,000,000 or near that number were rare at tempera-
tures below 15° C. About eighty-seven forms of Rotifera were listed.

The names used have been checked as closely as possible to cor-
respond with those indieated in Harring’s Synopsis of the Rotatoria.

co |

1920] Allen: Plankton of the San Joaquin River 8

Rhizota
Station I Station II Station IIT Daily Hourly
Number of forms recorded 2 3 3 3
Individuals per cu. meter.. 1,509 37,181 30,185 16,145

Practically all of the Rhizota found at any station were single
individuals without tubes. Only two or three times were colonial
forms recorded and then only part of the colony was present. These
facts serve to emphasize the adventitious character of the Rhizota
and to indicate that their presence in the plankton was due to broken
anchorage. The large numbers at Stations II and III as compared
with Station I suggest a decidedly deterrent influence of sewage.

DISCUSSION OF SPECIES

Collotheca pelagica Rous.

Station I Station II Station III Daily Hourly
PAV OLE G OW a eeren: cetewest fee nectiewsse 1,325 21,747 WGG29) sae casccee 1,477

Identification uncertain. May include two or three species, one
of which is possibly (C. mutabilis. The preserved condition does not
permit of very accurate judgment and the animals were usually with-
out tubes. So many of the tubes which were seen were of a slender
type.that it was thought that they indicated the species designated.
This form was only recorded at Station I six times (in small num-
bers), all in August, September and October with the largest number
in October. Occurrence at Station II was from August 15 to Novem-
ber 22. Most of the catches were fairly large and there were only two
failures to appear in that period. The largest number recorded was
in August, due probably to some unusual disturbance of the water by
barges or dredges.

Attached eggs of this genus and almost entirely of this form were
recorded with averages as follows: Station I, 185; Station II, 14,288;
Station IIT, 15,332. Although certainly adventitious, the combined
numbers of eggs and adults make this form of some importance in the
local river plankton for a brief period. It is not adapted to life in
sewage, however.

The following forms were recorded only onee or twice or were
thought to be present in fresh material:

Collotheca ornata Ehrbg. Once, I and III.
Conochiloides dossuarius Hudson.
Conochiloides natans Seligo.

Conochilus hippocrepis Schrank.

Conochilus unicornis Rous. Once, II and III.
Cupelopagis vorax Leidy. Once, III.

Ptygura brevis Rous.

88 University of California Publications in Zoology (Vou. 22

Bdelloida
Station I Station II Station III Daily Hourly
Number of forms recorded 6 6 3 3 2
Individuals per cu. meter.. 349,312 47,105 56,806 120,831 225,414

These large averages are perhaps unfair, inasmuch as they are
largely influenced by the assemblage of unidentified forms which was
assigned to the Bdelloida because it seemed almost certain that all but
a very few belonged to that group.

The only genus recorded is Rotaria and it is itself a heavy con-
tributor to the plankton. Probably some other genera are included,
especially in the unidentified list. The larger numbers at Station I
indicate a distinct preference for sewage, a condition directly opposite
to that of the Rhizota. The representation in February and March at
Station I is much heavier than at any other time of year, the maxi-
mum falling on March 12. This is very largely due to the abundance
of Rotaria rotatoria. The maxima at Stations II and III came in
October and August respectively, due to the greater influence of the
unidentified assemblage at those stations. It must be acknowledged
that the data for this group do not lead to satisfactory conclusions.
Some of the difficulty is due to the characteristics of the group and
some to the difficulty of identification in preserved material.

DISCUSSION OF SPECIES

Rotaria neptunia Ehrbg.

Station I Station II Station IIT Daily Hourly
WN) 2 33: enero ere ee eee 14,987 2,331 3,829 1,961 492

Identification usually positive. Occurrence most constant in cooler
months of the year at all stations. Much more abundant at Station
I, thus showing preference for sewage. Not recorded in April, May
and June at Station I and but rarely in July and September. Num-
bers small in March, species well represented in other months. Mavxi-
mum number recorded twice, October 15 and November 5 at tempera-
ture of 18.5° C., which is probably near the optimum. Small num-
bers in early January were probably due to the temperature being
below 10° C. Flood conditions may be responsible for absence in
April, May and June while high temperature accounts for it in July.
The reason for absence in September after being recorded in August
is not clear.

While definite pulses were present, there is not much regularity of
appearance.

1920] Allen: Plankton of the San Joaquin River 89

At Station II this form was recorded in every month except Feb-
ruary, April, May and June though the numbers were rather small
throughout and the catches mostly at irregular intervals. The maxi-
mum occurred in October at a temperature of 20° C. and again. at
17° ©. Conditions were much the same at Station III except that
April, June and July were the only months without catches. This
again supports the conclusion that flood and higher temperatures are
both deterrent factors. The maximum came in October.

While the habits of this organism would lead one to think of it as
really adventitious in the plankton, the large numbers here raise a
definite question as to the validity of that view. Can it be that this
animal has adopted a free swimming habit under our local conditions?
Or are the general conditions so favorable for development that favor-
ite haunts become rapidly overcrowded thus foreing individuals tem-
porarily into the plankton while seeking other quarters?

Rotaria rotatoria Pallas.

Station T Station II Station III Daily Hourly
DNS HW a-a e ey Eer P 287,186 19,099 18,283 54,197 8,500

Identification uncertain. Probably includes two or three other
species and possibly other genera. So far as estimated from lving
material the above named species was more numerous; the others could
not be distinguished from it while counting. Occurrence in every
month of the year at all stations, though rather light in April, May
and first half of June at each, and continuing so through June and
July at Stations II and III. The maximum came in March at all
three stations. The fairly rapid decline after the March maximum
was apparently due to the incoming mountain flood waters. There was
a marked pulse in July at the disappearance of these flood waters.
Higher temperatures undoubtedly kept the numbers down, however,
and none of the pulses of the last half year reached the numbers com-
mon in the first quarter year. This, of course, is also some indica-
tion that the comparative stagnation of the last half year was less
favorable than the disturbed hydrographic conditions of the first
three months when there was enough rainfall to cause considerable
local variation. Comparison with the 1914 condition when there was
heavier rainfall may help to settle some of these questions. The num-
bers clearly show that this form does best in sewage. There can be
no question that it prefers temperatures below 20° C. and the indieca-
tions are that it does best in waters slightly disturbed, as by local
rains, but this cannot be settled now.

No other forms of Bdelloida were recorded.

90 University of California Publications in Zoology (Vou. 22

Ploima
Station I Station II Station IJT Daily Hourly
Number of forms recorded 47 34 33 27 29

Individuals per cu. meter... 4,491,499 799,224 1,215,618 © 5,322,812 5,439,813

Ploima were invariably present at all stations throughout the
year. The averages given above include the eggs, of which there were
about 30 per cent at Station I and Station III and over 40 per cent
at Station II. While the numbers were always rather large they were
especially so in temperatures above 15° C., the maximum at Station
I occurring in June at a temperature of 22.5° C., in November at Sta-
tion IIT at 19.5° C., in November at Station III at 17° C. A marked
preference for sewage is proved by the exceedingly large numbers at
Station I, median numbers at Station IIT and smallest numbers at
Station II. The large numbers in late summer and throughout the
autumn at all stations also indicate a favorable effect of stagnation.

The fact that all the Ploima show strikingly uniform character-
istics of seasonal distribution, noted by Kofoid (1908) in Illinois is
strongly in evidence here, especially amongst the forms oceurring
throughout the year. Plates 3, 4 and 5 give a graphie representation
of the occurrence of the group as a whole (including eggs) accom-
panied by a similar graph for the chlorophyll bearers. This does not
indicate any prominent relationship of the two groups. The follow-
ing text table gives the more prominent pulses of Ploima at Station
I (exclusive of eggs). Omission or inclusion of eggs does not affect
the location of the pulses, hence eggs are not segregated from other
records in totals at Stations II and III.

Text TasLe 2. Srarion I

Date No. Date No. Date No.
Janis! os 258,268 Jan aoe 567,996 Feb. 12 ...... 1,985,200
Bebyi2ay eres 2,692,848 Mar. 12 .... 9,577,280 (ADT. ep) ee 5,398,400

... 6,026,912 May 11 ...... 9,936,352 June 3 4,359,872
June 25 _.. 13,717,568 July 12 .... 5,979,752 July 26 4,649,952
Aug. 20 .... 5,287,904 Sept. 13 ... 5,353,600 Octii8 ses 7,105,568
Noy os 802,848 Dees 14 2 723,508

It may be seen that of the seventeen pulses noted in this table
eight preceded chlorophyll and algal pulses by from three to twelve
days, usually three or four days. Coincidence occurred twice, and
there were two eases in which ploiman pulses followed the others by a
few days. In the other five cases no definite relation appeared. It
therefore seems that there is no such clearness of relationship of
pulses of Ploima and of chlorophyll bearers as was noted in Illinois

1920] Allen: Plankton of the San Joaquin River 91

(Kofoid 1908). Inasmuch, however, as ten out of seventeen pulses
came near to those of chlorophyll bearers it may be fair to assume
that the two groups are in some way interdependent or that the gen-
eral conditions favoring one likewise favor the other. The reiation-
ships at the other two stations were still less definite and it was not
considered worthwhile to transeribe the tables of pulses of Plotnna
there.

Our records are at variance with the Illinois records in showing
more pulses of Ploima to precede pulses of chlorophyll bearers than
to follow. The discrepancy is probably due to the errors incident to
escape of chlorophyll organisms through the net. But it might be
due to a difference in the numerically dominant forms in the two re-
gions or to some similar factor. The problem of difference cannot be
solved, apparently, from the 1913 records, but after all there is suf-
ficient likeness to warrant the conclusion that the two groups are
closely inter-related, here as there. The daily record was too short
to help in a decision on this matter.

DISCUSSION OF SPECIES

Anuracopsis fissa Gosse.

Station I Station II Station III Daily Hourly
PAG GUE 0 Glee wcnerecee seeasecet cesses 10,251 8,411 18,507 2,477 40,066
Average eggs attached...... 1,786 30 OAOMG) greeccstesseeneae 985

Identification frequently satisfactory, more often uncertain. Prob-
ably some loss through net. Not recorded anywhere during first half
year. Appeared at Stations I and II about mid-July, at Station ITI
in August. Maximum at Station I in November, at Station II in
August and at Station III in September. Occurrence frequent at
Stations I and III in August, September, October and November, dis-
appearing in December. Occurrence at Station IT rare except in
August. Apparently a form favored by warm and quiet water. Larger
numbers at Station III suggest a preference for moderate quantities
of organic matter in surrounding water.

All stations resemble Illinois in showing a distinct limitation of
this form to a four months period after midsummer. It was recorded
in June there and disappeared in early November. A single Decem-
ber record here at Station II indicates the possibility of occurrence
in very small numbers at other times. The pulses came mainly at
temperatures above 20° C., the single exception on November 22 pos-
sibly being due to confusion in counting.

92 University of California Publications in Zoology (Vou. 22

Anuracopsis sp. ; ‘ }
Station I Station II Station III Daily Hourly
VOTRQO Sciatic cesta 8,230 308 G19) Soe aeeeees 26,867
Identification doubtful. Record probably includes two or three
small forms with indistinct characteristics in the preserved condition.
Referred to this genus as the nearest probability. May inelude dis-
torted specimens of A. fissa. Since the only records of this form are
in June and July at the three stations, it may be that the whole num-
ber should be transferred to A. fissa.

Asplanchna brightwelli Gosse.

Station I Station II Station III Daily Hourly
YA OT GEO Be .ceseed a2 cececesscteesees 16,892 308 533 43,192 2,954

Species determination uncertain. Genus certain. Reeord prob-
ably includes at least two or three species under this heading, species
segregation being too difficult during the count. Eggs not counted.

Occurrence at Station I regular from mid-March to November I.
Maximum, 158,688, on July 5 but almost equalled in April and Octo-
ber. Reeorded only three times at Station II in April, June and
July in small numbers. Recorded five times at Station III from
March to November in small numbers and at wide intervals. Dis-
tinetly favored by sewage and by temperatures near 20° C.

The record at Station I shows ten fairly distinct pulses, seven of
which followed pulses of chlorophyll bearing organisms by from three
to seven days, two of which coincided with such pulses, while one
preceded. The correlation of these pulses is far the most impressive
of any yet observed. The following table, text table 3, shows tem-
peratures and pulses:

Text TABLE 3

April 9 18 132,240 Norileo One 20 41,600
May 21 44,800 May 27 HAVES 51,200
June 7 25 44.800 July 5 . 26 158,688
Aug. 26 44,800 Aug. 15 23.5 76,800
Sept 13° 25 51,200 Oct. 29 .... 19 105,792

Asplanchnopus sp.
Identification doubtful. Recorded three times each at Stations I
and II and six times in hourly series at Station III. Not important.

Brachionus.

Identification of the females of this genus was nearly always satis-
factory as to genus but the separation of species was frequently dif-
ficult and sometimes impossible. Males were never positively recog-
nized, hence species records were of females only. Eggs were easily

1920] Allen: Plankton of the San Joaquin River 93

identified when attached but the confusion was great when unat-
tached. Probably eggs of other genera were often included amongst
the free eggs. Eggs of species were not recorded.

Only seven species and one variety were recorded, although there
were probably many more. The reference of many individuals to
some of these species was somewhat arbitrary, but on the whole the
eight groups were fairly definite in the writer’s mind and may be
properly discussed despite some technical error in identifying.

Since the eggs were only recorded for the genus as a whole their
averages and the main features of their occurrence may be stated

now.
TExtT TABLE 4
Station T Station II Station III Daily Hourly
Ay. female eggs attached 255,960 16,390 28,607 409,180 132,240
Av. male eggs attached... 26,190 2,773 4,443 4,238 22,806
Av. female eggs free........... 351,039 14,780 41,963 718,362 396,720
Av. male eggs free.............- SIM is estes Iles apereaeecet eae

In view of the uncertainty of identification of unattached Brach-
ionus eggs either male or female, it is hardly worth while to attempt
any detailed discussion of the records for these kinds. The maximum
for both kinds of attached eggs came early in March at Station I.
Occurrence of attached male eggs was scattered after March, though
the female eggs were almost constantly present through the year.
They almost reached the March maximum twice in September. At
Station IT there were only three records of male eggs, two coming in
March. Occurrence of female eggs was fairly constant from June to
October inclusive, infrequent at other times, the maximum coming
in October. At Station III male eggs were recorded seven times, the
maximum in Mareh. The female eggs occurred rather regularly from
February to October inclusive, excepting April, when there were
none. The maximum came on October 4. About the only safe con-
clusion to be drawn from these inadequate records is that male eggs
are most numerous in early springtime at all stations. It is, of course,
unfortunate that the attached eggs were not segregated with the
proper species, but the desirability of segregation was not realized
until too late in the count.

Brachionus angularis Gosse.

Station I Station II Station IIT Daily Hourly
AMVISHEED) cee ncebecdoseecooccecceecotcn 78,367 3,417 4,675 14,579 8,630

Identification usually satisfactory. Occurrence far most conspicu-
ous in May and June at Station I, with maximum in mid-May. Miss-

94 University of California Publications in Zoology \Vou. 22
y |

ing in January, February, and December, rare in March, April, July,
August and October. Occurrence at Station IIT from April to Novem-
ber inclusive, but seattered and in small numbers with a maximum
in September. Limited to same period at Station III but regularly
recorded during most of May and June with maximum in May,
favored by sewage and by a temperature near 20° C. Stagnation
seems to be detrimental.

The periods of regular occurrence were too short to give very well
marked evidence of recurrent pulses.

Brachionus angularis caudatus B. and Da.

ion I Station II Station III Daily Hourly
300g 65,243 70,480 830,657 1,284,905

Identification usually satisfactory. Sometimes hard to distinguish

VASG OT OI Oly See eset nce ee eee

from type form of B. angularis. The separate record of this variety
seems to have been worth while because of the tremendous emphasis
which it gives to the continuity in occurrence of the two forms. The
variety was almost wholly absent from the collections until the type
form had passed the spring maximum. As the latter declined the
former increased until it entirely displaced the other. This was strik-
ingly true at all three stations. The variety also disappeared by No-
vember at all stations, at which time the type came in in small num-
bers for a few weeks. At Station I the maximum came on June 25
but was almost equalled in September. At both of the other stations
the maxima came in August.

Recurrent pulses were very marked in the records for this form
as shown by the following table:

Text? TABLE 5

Station I Station II Station LIT
June 7
June 25
July 12 July 12 July 12
July 26
Aug. 20 ‘ Aug. 15 Aug. 2
Sept. 9 Sept. 20 Aug. 31
Sept. 27

Oct. 11 Oct. 18

Comparison with the table of ploiman pulses at Station I shows
that four of the B. caudatus pulses correspond exactly while two oth-
ers are very close. It is thus evident that the relationship of oceur-
rence of this organism to that of the chlorophyll bearers is about as
intimate as that of the whole ploiman group.

1920] Allen: Plankton of the San Joaquin River 95

The larger numbers at Station I indicate favorable influence of
sewage and the distinct limitation to temperatures above 20° C. and
mark B. caudatus as a summer form. The maxima in late summer
may also indicate stagnation as a favorable factor. Kofoid’s refer-
ence (1908) to the contention of various observers that spinous pro-
cesses, ete., appear as adaptive responses to lessened buoyancy of
warmer waters is especially interesting in this connection. The con-
dition of our records more strongly supports that view than do the
Illinois records. In fact the evidence could hardly be stronger with-
out deliberate manipulation.

Brachionus budapestinensis D.

Station I Station II Station IIT Daily Hourly
PAN CT AGC) Stace snencessscescero-cesscsece 970 7,564 2,322 413 9,615

Identification doubtful. Recorded six times at Station I, thir-
teen times at Station II and seven times at Station III. Occurrence
at all stations rather scattered and mainly from July to October.
Maximum at Station II in August. Apparently hindered by sewage
but favored by warmth and stagnation. Not a very important form
here, though the average at Station I is somewhat higher than it was
in Illinois.

Brachionus calyciflorus Pallas. . (B. pala Ehrbg.)
Station I Station II Station IIT Daily Hourly
PATOTENEGY cis reste Seat nee cere reece 109,718 10,828 32,378 516 175,708

Identification satisfactory. No attempt to distinguish varieties in
final records. The above count consists entirely of females exclusive
of eggs. The most striking features in the record of the occurrence of
this form are its great abundance in the first four or five months of
the year at all stations, its abrupt disappearance at the close of this
period and its reappearance in considerable numbers in and after
August. The three stations vary considerably in these last two
points, the break in the record in May being much more abrupt at
Station I than at either of the others. Station I also shows only a few
very light catches in the fall while Station III reaches the maximum
for the year at that time. Station II has the maximum in February
but shows records of considerable numbers through September and
October. Station I has the maximum in March. The reasonable in-
ference seems to be that much sewage is favorable to this species in
flood water but that it is detrimental in stagnation. Also that tem-
peratures above 20° C. are rather unfavorable.

96 University of California Publications in Zoology [Vou. 22

The numbers here were much larger than those noted in Illinois
and the vernal maxima came about a month earlier. Otherwise there
is rather close similarity in the records. Recurrent pulses are not
distinct, however, at any of our stations here.

Brachionus capsuliflorus Pallas. (B. bakeri Ehrbg.)
Station I Station II Station III Daily Hourly
PASVOT APO! sascegesscnsecsecs eacseeeics 1,954 14,418 9,582 1,445 40,468

Identification probable. Oceurrence at Station I seattered, in
small numbers, from May to December, with a small maximum in
October. Occurrence at Station II almost limited to August and Sep-
tember, with a maximum in September. At Station III somewhat sim-
ilar, except for a slightly larger number of earlier records of small
numbers.

The likeness to Illinois conditions is very marked, especially at
Station IT. Our reeords indicate that sewage is detrimental while
stagnation and rather high temperature (near 24° C.) are beneficial.
It seems rather strange that though the river showed the largest num-
bers, the limits of their occurrence were much more sharply defined
than at the other stations; only four small catches being found out-
side of the eleven weeks period from August 2 to October 11, as against
twice that number elsewhere. No males were recognized.

Brachionus patulus Mill. (B. militaris Ehrbg.)
Station I Station II Station III Daily Hourly
Average 120 4,804 1,631 310 10,469

Identification certain. Recorded only onee at Station I in July
(6,400). Occurrence at Stations II and III limited to July and
August and September, except for one catch on December 6 at Station
II. Maximum on September 6 at both places. Evidently a summer
form favored by stagnation but intolerant of sewage. No data are
at hand bearing upon Kofoid’s suggestion (1908) that this species
probably thrives in warm, shallow water rich in organic matter. Its
absence from sewage does not prove that it would be injured by

decaying vegetation, ete.

Brachionus plicatilis Mill. (B. miilleri Ehrbg.)
Station I Station II Station IIT Daily Hourly
TNS) casesc es secceeessceceececee 9,179 977 965 ANS) ecczccctanece

Identification usually satisfactory. Occurrence at Station I mainly
in first three months, thereafter in small numbers at variable but
usually wide intervals through the year. Maximum (182,240) twice,

1920] Allen: Plankton of the San Joaquin Riwer 97

February 12 and March 5. Numbers always small at other stations,
otherwise distributed about the same. Hence this form may be said
to be definitely limited to temperatures below 20° C. Sewage appears
to be favorable.

This species is not listed by Kofoid for Illinois. Mr. H. K. Harring
designates it particularly as a brackish water form. It is also so
listed in Siisswasserfauna Deutschlands. However, its presence here
is not so prominent as is that of the brackish water diatom, Bacillaria
paradoxa. Some other factor than salinity must determine the occur-
rence of such forms.

Brachionus wreeus L.

Station I Station II Station IIT Daily Hourly
oreaee det 2 eek sy eet 139,352 8,558 2,871 352,237 36,606

Identification usually satisfactory. Some confusion with other
forms at times. Recorded in every month of the year at Station I.
Missing in March and November at Station II, in April, November
and December at Station III. There was a well developed pulse in
February at Station I but there were only four catches from March
I to May 14 when a long period of regular appearance in considerable
numbers began, which finally ended on October 29. Numbers were
then small and absences frequent to the end of the year. Maximum
(899,232) reached twice in June. Records scattering at Station IT
except in June, July and August. Maximum (105,792) on August 2.
Conditions similar at Station III with smaller numbers. Maximum
September 20, 38,400. This form shows a clear preference for sew-
age and for temperatures above 20° C., but stagnation is apparently
detrimental. Recurrent pulses are fairly distinct at Station I as
follows:

Feb. 8 July 26 Sept. 27
June 3 Aug. 9 Oct. 15
June 21 Aug. 23 Oct. 29
July 12 Sept. 9 Noy. 15

Of the twelve dates just mentioned, eleven can be connected defi-
nitely with pulses of chlorophyll bearers, four preceding by from
four to eleven days, four following by three or four days and three
exactly coinciding.

Brachionus with endoparasites. Average at Station I, 5,363.

Different species of Brachionus were found infested with parasites
but no specific count was made. These parasites were rather small
and their relationships were not determined. In almost all cases they

98 University of California Publications in Zoology (Vou. 22

occupied at least half of the space inside the loriea of the host. None
were noticed at Stations II and III so it is probable that sewage is
favorable to the parasites in some way. They were recorded five
times at Station I, one in June, thrice in August and once in Novem-
ber.

Diurella egg, free.
Station I Station II Station IIT Daily Hourly
SAS. GY'S Or fee asecen se nree ses eee 4,161 146,079 108,270 4,445 122,068

Identification very doubtful. Small eggs attached to filaments of
Melosira granulata were counted under this heading. They were only
recorded eight times at Station I but they were quite prominent at
the other stations, at Station II from June to October inclusive, at
Station III from May to October inclusive. Inasmuch as no consid-
erable number of Diurella females were ever found, it is probable
that these eggs were wrongly designated, but nothing is known as
to the real identity.

Epiphanes clavulata Ehrbg. (Notommata. )

Station I Station II Station III Daily Hourly
JAVOTAQO) 2Fceee cae creveceteecensceeeese= 1,263 6,400 DOA 3 5 Nore snneacncees) eerntrae ares

Identification uncertain. Reeorded five times at Station I, nine
times at Station II and seven times at Station III in August, Septem-
ber and October. Hence it is to be regarded as definitely limited to
stagnating waters and temperatures above 20° C. Sewage unfavor-
able. Attached female eggs were also recorded for this form at
Stations II and III.

Filima brachiata Rous. (Triarthra.)
Station I Station II Station IIT Daily Hourly
WARES Ld er cee eee rere eee ees 2,943 123 62 QOG. <.2ieeaectes

Identification certain. Recorded eleven times at Station I and
onee at each of the other stations. Occurrence at Station I usually
in small numbers at rather wide intervals. Catches grouped in May
and November. Maximum in November. This species was not re-
ported as present in Illinois.

Filinia eggs, attached.

Station I Station II Station IIT Daily Hourly
Female, average ................ 79,131 554 1,004 25667) 9 eee
Male, average :......-.-.----.----- 24,818 431 O51 sce Teeter

Identification certain. Attached female egg appeared in every
catch at Station I from February 12 to April 26, then frequently to

1920] Allen: Plankton of the San Joaquin River 99

July 19, being absent the rest of the year except for two small catches
in November. Maximum (1,481,088) in March. Recorded only five
times at other stations, mainly in March.

Male eggs were recorded continuously at Station I for a short
time in February and March and there were occasional catches to
June 28. They were recorded once at Station II and twice at Station
III in small numbers. Both kinds were first recorded at Station I
on February 2.

The maximum egg records of both kinds at Station I preceded the
maximum record for females of Filinia longiseta by three days and
the maximum for female eggs was almost reached again four days
after it.

Unattached Filinia eggs were not certainly identified though
recorded.

Filima longiseta Ehrbg.

Station I Station II Station III Daily Hourly
361,166 14,486 12,192 99,012 4,561

Identification positive. About twice as abundant at Stations IT
and III as ever noted by Kofoid in Illnois and about fifty times as

Average ....

many at Station I. Seasonal limitation earlier and more definite here
at all stations. Occurrence at Station I regular from January 5 to
July 19, missing thereafter except for two small catches in Decem-
ber. Maximum on Mareh 8, 6,083,040. Catehes of more than 1,000,-
000 taken seven times in February and March, three in May and one
each in June and July. An extremely important planktont at this
station. At Station II one small catch was made in January but the
regular occurrence began February 23, extending to April 13. Sev-
eral more catches to July 12, then none till late October, followed by
another in December. Maximum on March 8. At Station III one
small catch came in January, then the regular occurrence began on
February 8, extending with one lapse to July 12. Only two catches
thereafter, one in July and one in October. Maximum on June 28.

There were rather distinct recurrent pulses at Station I eulminat-
ing as follows:

Jan. 15 Feb. 23 May 7

Jan. 29. Mar. 8 June 3

Feb. 12 Apr. 13 July 5
Apr. 26

Contrary to Illinois conditions the principal occurrence of this
form was below a temperature of 20° C. instead of above, and from
March to July instead of from May to October, so far as Station I is

100 University of California Publications in Zoology (Vou. 22

concerned. In view of the enormous numbers at Station I it may be
safe to conclude that the food factor is more potent than temperature
and that the smaller Illinois numbers at lower temperatures were only
indirectly due to that condition. With abundant food in the sewage
the lower temperatures seem quite favorable here. This form may
then be regarded as very dependent upon sewage. The higher tem-
peratures and stagnating waters seem to be deterrent.

Keratella cochlearis Gosse. (Anuraea.)
Station I Station II Station IIT Daily Hourly
AV OLE GG) ocecsrccescceencea eer oosees 78,769 281,504 354,304 164,517 6,530

Identification usually certain. No attempt to distinguish varieties.
Some confusion probably of spineless varieties with spineless varieties
of K. quadrata or other species. The numbers were greater at all
stations than recorded for Illinois, but the reeords resemble Illinois
records in the fact that the organism was found at some station in
every month of the year. Also in the fact that there was a period of
regular occurrence in the first seven months of the year, separated by
a period of irregular occurrence or absence from a period of regular
occurrence in the last three months. The location of the maximum is
distinetly different from the Illinois condition at all stations. The
maximum there was early in May, while our records show a maximum
at Station I in July and at Stations II and III on November 1, the
last two being in remarkably large numbers. The inference from
our records is that sewage is detrimental in large amounts, that stag-
nation is even more so, and that temperature in moderate limits is
less important directly than are other factors. The optimum tem-
perature seems to be slightly below 20° C. The presence of largest
numbers at Station III indicates the probability that a larger amount
of organic matter than that in the river may be favorable.

Recurrent pulses are distinguishable at all stations, about half of
those at Station I corresponding closely with those of chlorophyll

bearers.

Station I Station II Station I1I
Feb. 12 June 18 Mar. 23 Mar. 23
Mar. 5 June 28 Apr. 19 Apr. 19
Mar. 19 July 5 July 12 May 31
Apr. 2 Oct. 26 Nov. 1 July 12
Apr. 23 Nov. 12 Nov. 1
May 7

This was numerically the most important planktont at Stations II
and III.

1920] Allen: Plankton of the San Joaquin River 101

Keratella quadrata Mill. (Anuraea aculeata.)
Station I Station II Station IIT Daily Hourly
BASU OTAGO) eeeecoe se sacense sence vseees 1,276,350 42,919 57,432 1,467,437 219,396

Identification usually certain. Contrary to Illinois records this
was numerically our most important rotifer, all stations considered.
It was one of the most important planktonts. Furthermore our rec-
ords show it to be a distinetly perennial planktont here, since consid-
erable numbers were found at all stations in every month of the year.
At Station I there was only one lapse in the record. The increase was
unusually uniform from January 5 to the maximum on June 28, fal-
lowed by a similar decrease to December 31. At Station IT the ocenr-
rence resembled that of A. cochlearlis in that there was a decrease in
numbers with a few absences in the summer months, thus making the
records for spring and autumn more prominent. The maximum came
on October 18 not far from the KH. cochlearis maximum. At Station
III the records for the summer were not materially different from
those for spring and fall except that the maximum came on October
11 in a much larger pulse than at other times.

Not only do our records fail to correspond with those of Illinois,
they also fail to agree at our three stations. Consider, for example,
the maximum in relation to temperature. - Station I shows a maximum
in a strongly developed pulse at a temperature of 23° C., Stations IT
and III at 17° C. Station I has its largest numbers in summer, Sta-
tion II its smallest and Station III much the same as in other seasons.
In spite of these differences some definite conclusions are possible.
The vastly larger numbers at Station I at all seasons indi-
cate not only a beneficial effect of sewage but the importance of the
food factor. The smaller numbers at all stations in January and
December show that temperatures may get low enough to be injurious,
though it is not clear that this may not be due to reduced food supply
incident to low temperature. In fact, when one considers that the
numbers appearing at Station I at 7° C. or 9° C. were as large as
those found in the culminations of ordinary pulses at the other sta-
tions in any season, it seems that the range of temperatures in ordi-
nary fresh waters has little direct bearing on production. The un-
usually strong pulses in October at Stations II and III indicate a
beneficial effect due to relief from Stagnation by the incoming
autumnal freshet waters from the mountains.

102 University of California Publications in Zoology [Vou 22

Recurrent pulses are quite prominent in the records for this form,
with eulminations as follows:

Station I Station II Station III
Jan. 15 June 28 Feb. 8 Feb. 8
Jan. 29 July 12 Mar. 29 Mar. 2:
Feb. 12 July 26 Apr. 19 Apr. 5
Feb. 23 Aug. 23 May 31 May 17
Mar. 8 Sept. 13 July 19 June 28
Apr. 5 Oct. 8 Aug. 31 July 26
Apr. 19 Dee. 3 Oct. 18 Oct. 11
May 11 Dec. 14 Nov. 30 Dee. 14
June 3 Dee. 31

Keratella eggs, attached.

Station I Station II Station IIT Daily Hourly

263,312 54,732 96,442 140,815 12,669
Identification certain. No male eggs were recorded and no effort

was made to keep the species record separate for eggs. The desira-

bility of such separation was overlooked until too late; hence, as

Average ....

might be expected, the egg record shows the same characteristics as
the dominant species, i.e., K. quadrata at Station I, and K. cochlearis
at the other two stations.

Keratella egg, free.

Station I Station II Station IIT Daily Hourly
PENNING | Ce neetee sesame ee 363,933 57,631 100,216 128,490 602,201

Identification quite uncertain. The designation was probably ecor-
rect in a large majority of the counts but there is enough uncertainty
to invalidate definite conclusions, so they are not offered.

Lecane luna Mull. (Cathypna.)
Station I StationII Station III Daily , Hourly

Average ...

Identification uncer
and II in small numbers, and once at Station III. Probably adven-
titious. At any rate unimportant.

Notholca striata Mull.
Station I Station II Station III Daily Hourly
INSEE eee soe. Se coerencsecin 165 1,692 BETO bens ae eo eee

Identification satisfactory. Count included a small number of
different forms most of which were considered varieties with perhaps
one or two other species. Only six catches at Station I at rather wide
intervals, in very small numbers and mostly in the first three months.
Occurrence at Station II in every month except December, seven
catches in first three months, one catch in each month thereafter up

1920] Allen: Plankton of the San Joaquin River 103

to December. Numbers always small. Maximum, 16,000, April 5.
Recorded nine times at Station III, seven times from January 23 to
April 19 and twice in November. Numbers always small but con-
siderably larger in November than at other times. It is clear from
these records that this form is intolerant of sewage and of summer
conditions, probably including temperatures, though the monthly
occurrence at Station Il may indicate the influence of a food factor.
At any rate the optimum temperature seems to be below 15° C. The
seasonal distribution at our Station III most nearly resembles that
noted for Illinois.

Polyarthra trigla Ehrbg. (P. platyptera.)

Station I Station II Station III Daily Hourly
INVOT ATC: eee ceersen tits beets 410,770 35,241 58,037 662,712 1,267,469

Identification certain. Recorded in every month at all stations.
Occurrence at Station I very constant after January 12, only two
absences, both in November. Maximum on May 7, culminating a grad-
ual increase from first appearance, numbers well sustained after that
except for a drop in June, another in November and the final decline
in December. Continuous record at Station II except for two misses
in June, one in August, one in October and three in November. Maxi-
mum on September 6 in a well defined pulse. Record at Station III
began on January 19, after which there was one miss in March, one
in June, one in October and three in November. Maximum on Sep-
tember 20 in a minor pulse. The character of the record at Station I
suggests the idea that temperatures may vary widely without appre-
ciable influence except as they approach the lower recorded limits.
Even here the influence may be through the food supply instead of
direct. Stagnation appears to be slightly favorable. This is next to
the most important species numerically, of rotifers at Station I.

Recurrent pulses are prominent at all stations as follows:

Station I Station II Station IIT
Jan. 15 July 30 Feb. 8 Feb, 8
Jan. 29 Aug. 9 March 8 Apr. 26
Feb. 8 Aug. 20 March 29 May 31
Feb. 23 Sept. 13 May 10 July 12
Mar. 8 Oct. 18 May 24 Aug. 2
Apr. 13 Nov. 1 June 28 Aug. 31
Apr. 26 Nov. 19 Sept. 6 Sept. 20
May 7 Nov. 3 Oct. 18 Oct. 18
June 3 Dee. 14 Dee. 14 Dee. 6
June 25 Dee. 31
July 12

These pulses at Station I are even more distinctly marked than
in Illinois, which of course might be expected from the very large

104 University of California Publications in Zoology (Vou. 22
numbers distributed over the entire year. The correspondence of these

pulses with those of chlorophyll bearers is quite close, thirteen being
within seven days of the same date.

Polyarthra trigla eggs, attached.

Station I Station II Station IIT Daily Hourly
Female, average 35,511 431 408 723 40,686
Male average 342 Cec) aneeshatti oebasceeteceet 8,138

Identification certain. Probably most eggs became detached in
manipulations and the records are to that extent unreliable. Certainly
there are some very curious features to the records as they stand.
Female eggs only were recorded at Station III in the regular series
and then in small numbers at wide intervals, but the hourly series
from the same canal, but a mile away, showed great numbers of both
sexes. At Station II the numbers of female eggs were also scant but
in the two catches of male eggs one was rather large. At Station I,
female eggs appeared irregularly in small numbers from the last of
February to the end of March, after which the occurrences were reg-
ular and in rather large numbers till May 11 when they abruptly
failed. Only a very few catches were found in the interval to mid-
November when the occurrence became regular again for several weeks.
The records of male eggs came in November.

Such records are quite unsatisfactory as it is evident that they do
not show the real numbers of eggs produced, in view of the large num-
bers of females recorded at all periods at all stations. Quite prob-
ably many of the free eggs counted as Keratella and Filinia eggs
should have been referred to Polyarthra. This was suspected early
in the count and the eggs were frequently examined for distinctive
characters in the groups but none were found that could be used accu-
rately while counting.

Rotifer eggs, winter, free, unidentified.

These were counted merely as a matter of routine in trying to give
attention to everything found. There is not enough certainty in any
observation concerning them to make comment desirable.

Synchaeta sp.

Station I Station II Station III Daily Hourly
PAU ONG Om serecmsserendaeennce stern e oto 76,696 35,039 83,865 19,850 25,890

Identification of genus satisfactory. Judging from living ma-
terial, three or more species were represented in the counts but they

1920] Allen: Plankton of the San Joaquin River 105

could not be accurately distinguished in preserved material. S. trem-
ula,, S. stylata and S. pectinata were probably most often present. Al-
though the assemblage was recorded at Station I in every month of
the year, the catches were few and small during the first three months
and in July, August, September and October. The maximum oceurred
on June 25 in a strongly developed pulse. The occurrence at Station
II was somewhat similar except that there were no large numbers till
July when there was a fairly strong pulse. The maximum came, how-
ever, in the larger November pulse. At Station III the numbers were
more evenly distributed from March to December, August being the
only later month with very small numbers. The November pulse was
largest on the whole but the maximum came on May 31 in a eatch
following a lapse and preceding two lapses. Such irregular records,
in addition to the difficult identification make it necessary to be eau-
tious as to conclusions. Still it seems clear that sewage is beneficial
and that stagnation with high temperature is harmful.

Trichocerca capucina W. & C. (Rattulus capucinus.)

Station I Station II Station IIT Daily Hourly
PENNS EMO prea eee eee 246 4,777 1,004 413 9,123

Identification uncertain. Genus probably correct in all cases.
Recorded only four times at Station I in small numbers and at wide
intervals; seven times at Station II, once in fairly large numbers;
eight times at Station III, all in small numbers. Unimportant numeri-
cally in our plankton. Probably adventitious.

Trichocerca iernis Gosse. (Rattulus gracilis.)
Station I Station II Station IIT Daily Hourly
PASV CLAD @rrcsere eens oe secede 13,097 21,577 46,414 88,913 285,187

Identification uncertain. May include other species. Not recorded
at Station I till May 27 and not appearing regularly till July 3.
Fairly constant through July and August and for a time in Septem-
ber, and October. Maximum in July. Occurrence at Station IT
almost limited to July, August and September with maximum in Sep-
tember. Conditions similar at Station III with a slightly longer
period of regular occurrence. Maximum in September. Evidently
favored by higher temperatures and quiet waters. Larger numbers
at Station III than in river suggest that more organic matter in the
water is helpful, though the organism does not do so well in the dilute
sewage of Station I.

106 University of California Publications in Zoology (Vou. 22

The following Ploima were only recorded once or twice, or were

only recognized in living material.

Ascomorpha ecaudis Perty.

Asplanchna priodonta Gosse. Once, I.

Asplanchna sieboldii Leydig.

Asplanchnopus multiceps Schrank. Once, I and III.

Diaschiza exigua Gosse.

Diaschiza gibba Ehrbg.

Diurella poreellus Gosse. Once, IT and III.

Diurella tenuior Gosse. Twice, I, and once, II and III.

Euchlanis dilatata Ehrbg. Once, IIT.

Filinia cornuta Weisse. Once, IT.

Lecane ungulata Gosse. Once, ITI.

Lepadella ovalis Mill.

Macrochaetus subquadratus Perty. Once, III.

Monostyla cornuta Miill.

Monostyla lunaris Ehrbg.

Mytilina mucronata Miill.

Notholea longispina.

Notholea egg, attached. Once, III.

Notommata aurita Mull. Twice, I, once, IIT.

Platyias quadricornis Ehrbg.

Pleurotrocha petromyzon Ehrbg.

Rhinoglena frontalis. Once, II.

Trichocerca endoparasitized. Once, II.

Trichotria curta Voronkov. Twice, II, once, IIT.

Scirtopoda

Pedalia mira Hudson was found in very small numbers once or
twice in fresh material from Stockton Channel but not in regular
catches for 1913.

GASTROTRICHA

Chaetonotus nodicaudus Voight and another species were each
recorded once at Station I. They are known to be present in the
locality in larger numbers and are, no doubt, strictly adventitious.

ENTOMOSTRACA
Station I Station II Station III Daily Hourly
PAN OLEUG © Giresrcetns seeetien. ceemearetae 560,149 22,022 22,551 1,498,724 83,099

With the exception of three specimens of Gammarus found at Sta-
tion III the Crustacea recorded consisted of Entomostraca. Of this
group only the Cladocera and Copepoda were of any importance in
our plankton. Entomostraca were recorded in every month of the
year at all stations, but the numbers were small everywhere during
the first three months and there were some misses at all stations at

1920] Allen: Plankton of the San Joaquin River 107

that period. In addition, Stations II and III showed occasional ab-
sences up to May and June, and in the last two months of the year.
The greatest abundance at all stations was in July, August and Sep-
tember with the maximum in August or September at all.

The count of Entomostraca is unsatisfactory for two reasons: first,
specific identifications were too difficult for the writer under the con-
ditions of work; second, the method of counting permitted too much
error. Special trials showed that even distribution of Entomostraca
in the counting cell seldom occurs. As the records stand, the main
error was due in most cases to counting only the same fractional field
as was counted for smaller organisms. It was the intention to make
a special count of Entomostraca later in order to correct this, but an
examination of the records showed that it was not probable that the
limited increase in accuracy of count would make any material change
in the possible conclusions. For that reason the intention of recount-
ing was abandoned. So far as can be estimated from several recounts
made at random, the variance in the count by the two different meth-
ods is mainly from 10 to 25 per cent.

Cladocera
: Station I Station II Station IIT Daily Hourly
Forms recorded .................- 8 4 4 2 2
Individuals per cu. meter.. 3,836 7,385 9197 ~ 7,432 34,752

The Cladocera were rarely prominent at any station. There was
probably a much larger number of forms present than was recorded,
since names were given only to those with conspicuous characters. The
averages were distinctly lower at all stations than they were found
to be in Illinois, except for one year there of recurrent floods. Since
1913 seems to have been an unusually stable year here, there is reason
for believing that the Cladocera are naturally fewer here. They were
recorded in every month of the year at some station but the catches
were few and far between and the numbers small at all stations until
August. The maximum came on October I at Station I and in Sep-
tember at Station II and III, after which the numbers rapidly de-
clined at all stations. Our records therefore agree with those of
Illinois in showing the favorable effect of stable (or even stagnating)
water and of high temperatures. We have the further indication that
sewage is detrimental since Station I had so much fewer numbers than
either of the other stations. The explanation of the deleterious effect
of flood waters in Illinois (Kofoid 1908) applies equally well here.
The evidence for recurrent pulses is not convincing here at any station.

108 University of California Publications in Zoology (Vou. 22

Discussion OF GENERA

Bosmina longirostris O. F. Mill.
Station I Station II Station III Daily Hourly
AINOYAQC: <eccccacsceccseetcreecerecnceess 746 5,000 5,145 1,652 13,684

Identification probable. This form was rare at Station I, being
recorded only eleven times in small numbers, six times in September
and October, the rest scattering. Catches at the other stations were
almost confined to the same period but there were more of them and
the numbers were larger. Clearly favored by warm, stagnating water
and retarded by sewage.

Chydorus sp.
Station I Station II Station III Daily Hourly
INS AEVEYEQS) bop sso eter eeooen renckaasee seco eEeeS 1,662 Oa] }3)e emeeen neers oare teed ee er

Identification doubtful. Recorded seven times at Station II mainly
in August and September, and five times at Station III at irregular
intervals. No definite conclusion possible, though the indication is
that sewage is injurious, while warm stagnating water is favorable.

Sida sp.
Station I Station II Station IIT Daily Hourly
ISS OENEGG) aoescnecteerreeennreencecaceoce 2,960 738 1,325 5,781 21,068

Identification doubtful. There was probably considerable confus-
ion with other forms, especially Daphnia. Recorded frequently at
Station I from early June to late October, rarely at other times. Num-
bers always small except on October 1 (105,792). Recorded twice at
Station II and seven times at Station III, nearly all in the warm
months. Seems to be a warm water form favored by sewage and quiet
waters.

The following other genera of Cladocera were thought to be pres-
ent:

Alona sp.
Bosmina sp. All three stations.
Daphnia sp.

Ostracoda
Ostracoda were mainly notable for their absence. Cypris sp. was
the only form recognized and it was rare. It was not recorded from
the preserved material. Inasmuch as it has been found in abundance
in ditches and temporary ponds about Stockton, it must be regarded
as strictly adventitious.

1920] Allen: Plankton of the San Joaquin River 109

Copepoda
Station I Station II Station IIT Daily Hourly
HMorms) recorded! Sees 4 3 3 4 3

Individuals per cu. meter... 556,312 14,882 14,549 1,488,421 189,469

Copepoda were recorded in every month of the year at Station I,
and they were entirely missing only at Stations II and III in Decem-
ber and November, respectively. Numbers were small at all stations
through the first three months and in the last month. At Stations IT
and III they only reached 100,000 in three catches in September at
the former, and one catch at the latter. There was no increase in num-
bers at either place until May and the decline was very rapid after
September. On the contrary, Station I showed very marked and
steady increase in numbers after March and the decline after Sep-
tember was gradual, though starting abruptly with the close of the
month. The maximum at Station I came in August according to the
record but it was so nearly eqalled in September that a recount might
show it really to be in that month. However, this does not affect the
general conclusion that the warmest months are most favorable, the
culmination coming with approaching stagnation. The record also
clearly shows that the dilute sewage of Station I was distinctly favor-
able to this group.

Specific identifications were not attempted and there was certainly
some confusion of forms during the count. Some of these errors could
be corrected by a recount, but in the writer’s judgment there would
not be enough advantage to warrant the great effort involved.

Dr. C. D. Marsh, of the United States Bureau of Plant Industry,
very kindly identified a few forms from a very limited amount of
material sent to him. He noted the presence of Cyclops americanus
Marsh, Cyclops prasinus Fischer, and Cyclops albidus Jurine. No
other Copepoda were found in the samples sent to him but the writer
is certain that some other forms occurred at times in hmited numbers.
Since Cyclops completely dominated the other genera in numbers, dis-
cussion of seasonal distribution will be deferred till discussion of
that group is reached.

DISCUSSION OF GENERA

Canthocamptus sp.

Identification fairly certain. Reeorded only twice at Station I,
thrice at Station II and five times at Station ITI in small numbers and
at wide intervals, but mainly in spring and fall. This genus has been

110 University of California Publications in Zoology (Vou. 22

found in abundance in some of the shallow temporary ponds in Stock-
ton in February, March and April, hence it is to be regarded as
adventitious in the plankton collections.

Cyclops sp.

Station I Station II Station IIT Daily Hourly
Average .62 = ae ee 165,660 2,238 7,929 525,978 83,099

Identification of genus usually certain. May include some other
genera when preservation of the individual was poor. As mentioned
above, Dr. Marsh has indicated the presence of three species in the
first half year. These were C. americanus Marsh, C. prasinus Fischer,
and ©. albidus Jurine. It is probable that there were few other
species and that these furnished the principal numbers.

The genus was rarely missing at Station I, though the numbers
were comparatively small before May and in December. Only two
catches were recorded before June 21 at Station IT and two after Sep-
tember 13. Conditions were somewhat the same at Station III,
though the number of catches before mid-June was larger. The evi-
dence seems to be conclusive that the genus is favored by sewage, by
stagnation and by high temperature. It does not seem possible that
recounting by any method could change the basis for such conclusions.

There is some evidence of recurrent pulses at Station I but a
recount would be necessary before listing them with full confidence.
As it stands, no very close relationship to the algal pulses ean be
shown except in two or three cases.

Diaptomus sp.

While this genus does not appear in the record, it is so certain
that it was present that definite mention of the fact seems desirable.
It may have been sometimes included in the count with Cyclops, but
the numbers were never very large and it may have failed to get into
the counting field except in one or two cases.

Nauplius spp.
Station I Station II Station III Daily Hourly
PAS OT SLD Oceans wonton arertasecereraerae 392,240 11,722 5,239 962,366 106,370

All kinds of larval copepods were included under this heading.
Undoubtedly, nearly all belonged to Cyclops. They showed practically
the same characteristics of distribution at all stations as those already
noted for Cyclops, almost the only difference being that more catches
were recorded. This might be expected since such a variety of larval
forms was included in the count.

1920] Allen: Plankton of the San Joaquin River ili

No copepods other than the forms already noted were recorded
from the 1913 collections. Since most of the Entomostraca were quite
well preserved, it may be possible to make a critical study of the
group at a later period.

MALACOSTRACA

Three specimens, probably Gammarus sp., were found at Station
III in January, 1913. They were taken from very shallow water be-
fore the best place for collecting was found and they were evidently
adventitious in the plankton.

ide MISCELLANEOUS
Glochidia spp.
Station I Station II Station IIT Daily Hourly
PASVICTELE C) coco ares sateen teeeenseonesm 256 6,415 471 TB) ssstsccchecescs

General identification certain. May include larvae of several
species of fresh water clams. Recorded three times at Station I in
July and August and five times at Station III, mostly in the same
period. At Station II the numbers were much larger and the catches
more numerous. Recorded three times in January and February in
very small numbers and almost continuously in June and July. Sew-
age evidently detrimental and flood water favorable to occurrence in
the plankton. Effect of temperature uncertain.

Macrobiotus sp.
Station I Station II Station III Daily Hourly
PAS OT ALG eeeas eben rate ee tet 80 854 Qi2GB' scessecsdcteson | cbexsdeccsecsace

Identification satisfactory. All the Tardigrada found were referred
to this genus. It was only recorded twice at Station I, eleven times
at Station II and three times at Station III, always in small numbers.
Evidently adventitious.

Nematoda sp.
Station I StationII Station III Daily Hourly
INS QUENERG), ceeenseee eastern eras 212 185 G8 A RE c eee eagles oneeie

Identification of the order certain. Nothing definite known as
to generic classification. Very many specimens were immature. Re-
corded six times at Station I in small numbers and at wide intervals,
twice at Station II, and five times at Station III, these five being
taken in the first three months. These are evidently adventitious
forms in the plankton.

112

University of California Publications in Zoology

[ VoL. 22

Other groups represented by only one or two forms or seen only

in fresh material are as follows:

Chironomus larva. Twice, IT.
Oligochaetes. Three times, II.
Nais (?) sp.
Oelosoma sp.

Summarizing, it may be worth while to call particular
to the number of forms present at different stations in

Planarian.
Statoblast of Pectinatella.
Statoblast of Plumatella.
Hydrachnida sp. Twice,

(7)

(2)
Il.

attention
different

months, and to the proportional differences in numbers of organisms
at the three stations by months, as shown by the accompanying text

table.

Text Tasie 6.—NumBeERrs OF KinDs OF PLANKTONTS BY STATIONS AND BY MontTHS

IN 1913
January February March April
Stations I Il Ill I inf 300! I Il Il I IE “TUE
Bacteriaceae............0..cc0cccee.- 50 L 0 ON Oe OO OCR a0
Schizophyceae..... Ta, 4 130 lie AS oie Oe Onn Omni Mee
Chlorophyceae..... oi GMP St 59) GS a6" Sees) someone oO mmmEsS
Bacillariaceae................c000.0+ 24 28 18 22 28 28 26 34 38 27 37 33
Gonjugatiesin acne ee pO ome COUN ae eens op elm ao ec OR
Mastigophora...............::.:c0se0-00- 6b onl OG aL eS eee ee Om
IRIDTZO POCA meteee seen Vi eee COMES mec opm h it. Gy.
Ie OZ Ore cess: OF 70) FO OF OF ON pie Shoe Ome
Ciliatarene tect: NBS PP ey lye a ans Uf MO) ts}
DUCHORIA chia eye ee een eee Oo OO WM GO OF oO © OW O ut ©
RUDIZOta eee cee eee Q a @ @ © 0 © @ © @ @
Bdelloidatrcmeunsee cee ae 3) 8, 12). FSS) li ole shel) eo ore
IPI GUN arise eee roe 2 ed 10 (9 102 Ob 2 eet)
Cladocera... Ie SIM a Ol 00” On 90s 0 eee
Copepoda........ ee ee ee ee eee re eh ate
Miscellaneous...................0.-.+- Sol 4 AI ah ty OS, eee ee
Motels coe eee 83 69 51 89 73 82 92 91 96 98 90 91
May June July August

Stations ut Il Il I IN Ane I i HU I Ti Lie

Baeteriaceaen. cscs 2 2 A 0) AT ie ee SOP eel gee eee
Schizophiycederres ese. QS) 6 LO LOSS rel O eerie ee ee
Chlorophyceae. LOM AS Sr oly eS elo OO RO a.
Bacillariaceae... 25 87 31 23 42 34 18 35 29 22 35 38
Conjugatae....... 1 G4 2 4A aR S51 5) eb Eb eeone Gao:
Mastigophora.. 10). 3% 149 “94 29) 1 0) M2 ee So
Rhizopoda........ Gu 2) 92 Ae ao oe) von eo, 4e Omeo mn
Heliozoa.......... Ie Ola 24, BOS 4 a cs
Gilat eins, sees etee reise 8 ae bucdre 8) ASibeio 2 eo ee.
Suctoria...... OO OW Oh Oss te i oO eB
Rhizota...... OW) 2 OO) 2 © @ 8 Bi
Bdelloida te iene 2. D2 De Zi ON) eg os ae
Ploima.... 16) 9) 15) 16 5 13516) 20 Loe ae oeetG
Cladocendint Bere. ers Lie UR ON ee a ee 2 oS
CWopepodase cnmrncn scree: aa rs eee eee ee ene ie A ee
Miscellaneous..............::.c00e000e 1 5 10F AE Oe ee ee ee
Ota Ne, cacAtsskevactievas 93 86 84 87 98 92 91 107 101 107 122 116

1920] Allen: Plankton of the San Joaquin River 113

Text TABLE 6.—NuUMBERS OF KINDS OF PLANKTONTS BY STATIONS AND BY MONTHS
IN 1913—Continued

September October November December

Stations I 10h Auge I Il Il I IME IDE I Ine BABE
Bacteriaceae..:........c.ccccecs cs tO al EOS le ya 1 ON sd.
Schizophyceae... 1) il) ail i KO GB) a ihl eS}
Chlorophyceae... sce, Wik @. ail) “ant asl ak al@) alah al@! at GY
Bacillaniacesder........:.0000--- 2222S Zomolen 26) 29) oo) o2) 6298130
Wonjugatae nn. csentceecee eee DORE RODs c Ome VOmmE ee ome’ si 4) by 4
Mastigophora.... sorccomnces aly 1 GG) 83) a) IE KO) aha} ES 8)
RbizOpOGa eee tenn NG) i eenOn 0G 40 ore 5) (6h 75) 94> a3
Heltoz0aeee ee eee ee BO oad “Oo Po Pst M2 Ze = iO
Ciliata ieee ooo = 8 8 OU 9G Go de oe) ahh 20 Ga
SUCUOnI Se eee a fll al Wo PAE eRe PN Oe SS ae al
Rn ZO LAE e net eee. 1 1 1 1 1 10) 1 OW)
Bidellloidae ere eee ae BB} (BBY aS PEE SSR Sh RRAE CRY)
IVb ykeavaye as et seen 5 ue ee eee Usy al7/ UG} als) alts a aaa) salad 8 12 4
Cladoceraerersssts. eee eo 2s Doe Seat Qe ot 2 ali
(Choe) SOKO ago ontecosoucdnpseomencarc leew eee ey lh Oh EO Al
IMINSOCIENAG ONE Kos naccssccosccoscaccce =O LO) AO al ah ah OE Ty al
MRO Gala ens Reus eee 104 108 108 116 100 101 108 101 107 115 85 8&8

This table shows some points quite well. The number of forms
was lowest at all stations in January. There was then steady increase
to May, when flood waters were highest and the number of forms re-
corded shghtly less. Increase in number of forms began again in June,
becoming greatest at Stations II and III in August and at Station I
in October. The numbers were well sustained at the two stations
until December, when there was a marked decrease. Station I not
only showed increase to October, but almost equaled it in December.
While it is probable that more accurate species determination might
change the detail of this showing, it is not probable that the general
differences would be affected.

One legitimate inference from this table is that Station I is less
subject to seasonal fluctuations than either of the other stations. At
present the only reasonable explanation of this fact seems to be that
the dilute sewage of Station I is the prime factor, for the superficial
resemblances would lead one to expect that Stations I and III would
most closely approach each other in character and distribution of
populations, rather than Stations II and IIT. But the reverse is true,
and sewage is the only known factor of sufficient moment to account
for it. It is true that temperatures run slightly higher at Station T,
but is it not possible that this higher temperature is partly due to the
rapid turnover of the great quantities of organic matter.

Aside from the question of temperature there is ample reason for
assigning main influence to sewage because of the great food supply,
a supply superabundant and hence essentially constant through the

114 University of California Publications in Zoology [Vou 22

year, with the exception of May and June, the time of the mountain
floods. The decrease in number of forms at this time strengthens
the view that flood waters dilute the sewage and reduce the food
supply, thus reducing reproductive and growth activities. There is
also considerable loss through washing out, even with the rather low
waters of 1913. The 1914 collections should certainly throw some
additional light on this question.

THE DAILY SERIES

As noted elsewhere, the daily series was undertaken in the hope
that it would give definite information concerning the problems of
recurrent pulses and the incident conditions. This hope was partly
realized, although the thirty-one days constituting the series was not
enough, and it is evident that more faithful adherence to a uniform
hour of collection is desirable. Since this last would involve very
marked differences in condition of tide, it is probable that Stockton
is not a good locality for such a test. It would be much better to try
it in a locality free from tidal influence. It is also probable that
the large amount of traffic past the point at which this series was
taken might affect the results. At any rate, these two factors, at least,
might be eliminated in some other locality. However unimportant
they might later be proven to be, they do make the problem need-
lessly complex.

Under the circumstances it does not seem desirable to discuss
individually even the more conspicuous species. Generalizations to
be reached by such discussion in this series do not differ materially
from those to be obtained from consideration of the larger groups.
Species records are given in table 4.

Although the thirty-one days did not give a series of sufficient
length to be wholly satisfactory, there are some points of decided
interest. These are graphically indicated in plates 1, 6, and 3. In
plate 1, showing volumes, there was a prominent pulse apex on July
13, another maximum for the series on July 18, and another almost
as large on July 27. Explanation of this is afforded in part by
plate 6, where it is shown that chlorophyll bearers and Protozoa and
Rotifera all had pulse culminations near July 13 and July 27, while
the Entomostraca showed a pulse culmination maximum for the series
on July 22. It is evident that the median position of the volumetric
maximum is due to its dependence on the entomostracan numerical

1920] Allen: Plankton of the San Joaquin River 115

maximum since the bodies of individual Entomostraca are so much
larger than those of the other planktonts. Just why the numerical
maximum of Entomostraca should fall between pulses of other groups
does not so clearly appear. The most obvious explanation is that
the abundant food supply furnished by other organisms near July 12
led to abundant reproduction of Entomostraca (mainly Cyclops),
which in turn reduced the number of other organisms and led to its
own decline. The pulse culmination of other organisms at July 27
would then be due to rapid recovery from the inroads of the Ento-
mostracéa.

On account of insufficiency of records, consideration of light rela-
tions does not give very satisfying aid toward an explanation of these
pulses. Both our records and those of Mr. Higby, the Stockton
weather observer, were made at a particular time of day and so fail
to show the day as a whole so far as clouds, ete., were concerned.
It is also true that such records fail to show the influence of the wind
except for a small part of the day. As the records stand (table 7),
the daylight conditions appear to have been too nearly uniform
through the series to have had any marked influence on plankton
pulses.

Reference to the lunar eyele for July, 1913, however, suggests the
probability of its having a strong influence in this connection. It
may be noted that the beginning of the marked rise in production
of chlorophyll bearers came on July 10 at the first quarter of the
moon, and: that the apex of the pulse for these organisms came on
July 17, at full moon. The rapid decline thereafter may be easily
explained by the unusual abundance of Entomostraca and other preda-
tory animals, while the smaller pulse culminating on July 27 might
be due to partial recovery from their attacks. The evidence here that
the waxing moon brings rapid increase of chlorophyll bearing organ-
isms is as strong as could possibly be imagined, since the record covers
only a single lunar eyele. It makes one wish that the daily records
might have been carried over several lunar cycles in order to find the
variations which might be expected. This particular series certainly
confirms in a definite way Professor Kofoid’s argument (1908) that
pulses of chlorophyll bearers, and consequently of other planktonts,
tend to accompany increases of lunar light.

The important features in the records of this series are concerned
most directly with the chlorophyll bearing organisms, as just discussed.
But, as a matter of interest, brief mention will now be given of the

116 University of California Publications in Zoology |Vou. 22

typical Protozoa (Mastigophora are included above with chlorophyll
bearers) and of the Rotifera. Examination of plate 6 discloses the
fact that Protozoa showed pulses at about the same periods as did the
chlorophyll bearers, slightly preceding the latter at the first and coin-
ciding at the second. The evidence which this gives of close associ-
ation of the two groups is the only important feature. The analysis
of the relationship presents some decided difficulties. In the first
place, most of the Protozoa found here at this time were of the type
which depends upon bacteria for food rather than upon green or-
ganisms (at least no Protozoa were ever observed with green organisms
in their bodies). The presence of green organisms might favor them,
however, by exeretion of oxygen and absorption of carbon dioxide.
Aside from these considerations, the only reason for coincidence of
pulses in the two groups would seem to be in general conditions
favorable to both.

In the ease of the Rotifera, the abundance of food with which
most of them are furnished by an increase in green organisms would
seem sufficient to account for close correspondence of pulses of the
two groups. Unfortunately for the validity of this view, the first
rotiferan pulse (pl. 6) culminates on July 12, five days before the
culmination of the pulse of chlorophyll bearers. It is also true that
the second pulse coincides exactly with that of the green organisms.
If the food relationship were the deciding factor, the rotiferan pulse
should always follow. It is possible that here again is a case in
which the gaseous content of the water forms one of the connecting
links for two groups of organisms.

SUMMARY

Considering the large numbers of factors which might influence the
location of pulses of various organisms or groups of organisms, it is
necessary for the present to say that the showing made by this daily
series of a single lunar cycle may be to some degree accidental.
Hence no inference can be regarded as proven. The important
inferences suggested by these daily records may be summarized as
follows:

1. There was a very distinct increase in numbers of green organ-
isms as the light of the moon increased.

2. There was an abrupt decrease in green organisms as Entomo-
straca increased, which was followed by a partial recovery after the
entomostracan maximum.

1920] Allen: Plankton of the San Joaquin Rwwer La le/

3. The two pulses of chlorophyll bearers were closely accompanied
by similar pulses of Protozoa (exclusive of Mastigophora) and of
Rotifera.

4. It is very necessary to have similar series covering several lunar
eycles in order to evaluate the various factors of distribution and the
bonds of relationship of plankton organisms.

Before leaving the discussion of this series, the point should be
emphasized that daily collections frequently give a very different view
of the situation from any that may be obtained at longer intervals.
Comparison of plates 3 and 1 (graph Station I and Daily) shows this
very clearly. Referring first to plate 1, it will be seen that although
the regular Station I series was taken twice a week the difference is
very great. In the Station I regular series the volumetric maximum
came on July 30, but the daily record shows that four catches (July
13, 18, 20, and 27) exceeded it, two of them greatly. The semiweekly
record shows this maximum on the rise of a pulse while the daily
record shows it as on the decline of another. The daily record also
shows marked fluctuations in volume of the catches during this lunar
eyele which are not indicated by the other.

If the regular series had been taken only once a week (which is
usually the shortest interval used by investigators), the dates would
have been July 5, 12, 19, 26, and August 2. Comparing this with the
daily record we see that it would have shown an erroneous picture
of conditions since it would have indicated a considerable abrupt rise
in volumes to fairly stable, higher levels.

Turning to plates 3 and 6, we find the same things true. In the
case of the Entomostraca the remarkable pulse from July 20 to 23 is
entirely missed by even the semiweekly method. While the pulses of
the other groups are not entirely missed, they appear much more ab-
rupt in the regular series than they really are.

In consequence of these remarkable differences it is surely clear
that only the most general conclusions may be safely drawn from
series of catches taken at intervals greater than one day.

THE HOURLY SERIES

This series, covering a period of about twelve hours on August 11,
was undertaken in the hope of finding some indication of the import-
ance of the daily tidal currents in a study of the plankton. It was

118 University of California Publications in Zoology [Vo 22

also expected that some information might be obtained as to diurnal
influences of light. The series is too short to be satisfactory (twenty-
four hours would be better) and several days should be covered in-
stead of one.

Despite these defects, the records indicate some points of interest.
It happened that on the day selected low tide came at about 11 A.M.
at Stockton, but there was no available way of recording the tide
accurately. There is nothing in the record that can be positively
connected with tides.

Still less than in the Daily series does there seem to be anything
indieated by the species record which is not as well shown by major
groups. For that reason the general discussion only will be given.
Reference to table 5 will easily show such detail as has been recorded.

Since chlorophyll bearing organisms give, to a large extent, the
basis of interpretation of plankton conditions they may receive first
attention. Plate 6 (hourly) shows a preliminary drop in numbers
from 7 A.M. to 8 A.M. a nearly uniform succession of catches to 12 m.
and a constant rise through the remainder of the series to the close
at 6:45 pw. <A graph of such very prominent characters demands
explanation, but the demand cannot be fully satisfied from the present
records. During the forenoon period of nearly uniform numbers the
tide was ebbing, the air was hazy with full sunlight, there was little
wind and the water was nearly smooth most of the time. In the
afternoon period of rapidly and constantly rising numbers there was
flowing tide, hazy air with full sunlight, strong wind, almost a gale
at the close, and very rough water, with strong cross currents due
to wind. The water temperature varied from 24° C at 7 a.m. to 26° C
from 11 a.m. to 4 p.m. and to 25° C at 6:45 p.m. Among the observ-
able factors involved, the temperature seemed to be the only one of
sufficient constancy to account for the inerease. Light was the only
other factor that seemed likely to have had a beneficial effeet and it
was surely very much poorer in the afternoon on account of rough
water. In view of such adverse conditions as rough water and poorer
light it would have been reasonable to expect that there would at
least be no increase in numbers of plankton in the afternoon. As
the evidence stands it points distinetly to the conclusion that temper-
ature was the dominant factor in the diurnal fluctuation of chlorophyll
bearers.

If there had been only one or two larger catches in the afternoon
or if there had been fluctuation in numbers there might be some

1920] Allen: Plankton of the San Joaquin River 119

question as to the sufficiency of the above evidence, but it will be
noted that after 12 m. there was a steady increase broken by only one
fall below the last preceding number and this break occurred at 6 P.M.
A more detailed analysis of the chlorophyll bearing group very forci-
bly emphasizes the reliability of the record covering this point. In
plate 11 it will be seen that Schizophyceae and Bacillariaceae have
very pronounced increase after 12 o’clock, while Chlorophyceae and
Conjugatae have moderate increase, somewhat wavering, and that
Mastigophora have a strong but erratic rise from greater numbers at
1 p.m. a low minimum, to 7 p.m., almost equal to the forenoon maxi-
mum. It is also clear that all these except the Chlorophyceae show
the sharp temporary decline at 6 p.m. Looking up species records
in table 5, we find that the 6 p.m. decline is mainly due to deficiencies
in numbers of Nostoc and Cyclotella. Also that the erratic record of
Mastigophora through the day is due principally to Chromulina,
Hemidinium and Trachelomonas, all very difficult to identify or to
count. Taken as a whole, the evidence indicates that the records
give a fairly dependable idea of the history of the chlorophyll bearers
through the twelve-hour period. From this history the tentative con-
clusion may be drawn that temperature is a major if not the deter-
mining factor in daily fluctuations of numbers. It may be, however,
that wind and waves do not exclude enough sunlight in shallow water
to make any great difference and that the greatest influence in this
case was due to sunlight. This last view is supported by the history
of the other groups.

In case of the Protozoa, the Rhizopoda (pl. 11, and table 5) and
the Heliozoa (table 5) give responses similar to chlorophyll bearers,
i.e., an afternoon rise; but their numbers are relatively small, for most
of the catches and their afternoon prominence might easily be due
to the stirring of bottom waters by the strong currents caused by
combined wind and tide. This leaves, then, the Ciliata as the only
typical protozoan group with a reasonably clear record. Reference
to table 5 shows the ciliate assemblage to consist almost entirely of
Holophrya, Tintinnidium and two Vorticella and that they all agree
in a strong forenoon representation with an afternoon decline, well
pronounced for three of them. Since temperature would be expected
to affect these as markedly as it did the chlorophyll bearers, while
light probably would not, we have a valid conclusion indicated that
light is the major factor in the afternoon rise in numbers of chloro-
phyll bearers.

120 University of California Publications in Zoology (Vou. 22

The Rotifera (pl. 19) show substantial agreement with the Ciliata,
both collectively and individually. Hence we are still further led to
doubt the dominance of temperature.

As to Entomostraca (pl. 19) the catches of Cladocera were too
variable to give any information, and those of Copepoda were also
rather indefinite. There was not much difference between the forenoon
and afternoon catches either of Cladocera or of Copepoda or of both
together.

As shown by plate 1, the whole plankton volume increased strongly
through most of the twelve hours, both actually and also relatively
to the volume of sediment. No explanation of this faet seems to be
available, although the distribution of the chlorophyll bearers may
be of sufficient importance.

The foregoing discussion leaves a final impression which is badly
muddled. This may truly represent the facts, but it is not satisfying
to the mind. A different form of discussion may help to clear the
problems involved. Examination of tables and plates already men-
tioned discloses the fact that, based on distribution through the twelve
hours, there were two fairly well marked groups of planktonts, con-
sisting on the one hand of the chlorophyll bearers and on the other
hand of the more highly motile animal forms. The former showed
a steady increase in numbers as the hours of afternoon passed. The
latter showed just as pronounced a decrease, though less uniform,
from the forenoon numbers.

Apparently the general factors which could probably be involved
are the following: vital, chemical and physical. While specific sub-
divisions of these make a formidable lst, which is further complicated
by their very general interdependence, it seems that some are suffi-
ciently dominant to enable tentative discussion, as in the acecompany-
ing list:

Vital Factors Chemical Factors Physical Factors
Locomotion Organie content Viscosity
Irritability Mineral content Turbidity
Feeding Gaseous content Suspended solids
Respiration ¥ §Tide
Excretion Currents Wind
Reproduction Oscillations
Other organisms Temperature

Light

Pressure

Locomotion, among the vital factors, is characteristic of the typical
animal forms, but its effectiveness may be increased or diminished by
respiration and excretion, or other factors, in the same animal or in

1920] Allen: Plankton of the San Joaquin River 121

neighboring organisms of any type. It may be similarly affected by
the gaseous content of the water, which in turn is determined to some
extent by temperature, light and currents in water and air, and so
on with an indefinite number of combinations. It is necessary to limit
our present discussion to those combinations which are most probably
determinative within the twelve-hour period. Continuing the refer-
ence to locomotion with this limitation in view, we have to note that
the more typically animal organisms may have been less numerous in
afternoon catches because of migration to bottom layers of water, the
lowest of which the net did not reach. Such a migration might be
due to the influence of several other factors. Rising temperature
might induce it directly by discomfort or indirectly by lessened vis-
cosity of water, relatively increasing the influence of gravity, or by
reducing the gaseous content, probably not greatly effective, or by
changing the gaseous content through more oxygen exeretion and
carbon dioxide absorption by green organisms, or by increase of dis-
agreeable excretions from the surface organisms as they became more
active under higher temperature.

Locomotion might also be affected by the wind, directly by dis-
comfort due to surface agitation, indirectly by interference with food
taking near the surface through rapid oscillations of surface layers
of water. Leeward drive of the wind is not considered because it
would affect green organisms as much or more than the locomotor
organisms.

Light might affect locomotion directly by discomfort and indirectly
by the increase of starch manufacture, in green plants, with the larger
amount of oxygen liberation and carbon dioxide consumption, thus
shifting the region of the mean gas content to which motile forms
are accustomed, to some distance below the surface.

Locomotion might affect non-motile surface organisms through re-
moval of predatory organisms by migration, thus letting growth and
multiplication go on unchecked. It would not be necessary for an
organism to pass a whole life cycle in order to show this effect. Un-
doubtedly there are at any given moment in a plankton population
many very young individuals, many just maturing, and many just
ready to divide. Unfavorable conditions would arrest or deter devel-
opmental processes which would be again accelerated by favorable
conditions. At a favorable time, then, many new organisms, which
had been restrained during an adverse period, might be liberated and
allowed to grow.

122 University of California Publications in Zoology |VoU. 22

Reproduction as a factor influencing diurnal oscillations of num-
bers may not be important, but, for the reason just stated, it probably
is. If, in addition to this, it could be shown that any considerable
number of plankton forms accelerate both growth and fission pro-
cesses with diurnal rise in temperature and that fission may occur
two or more times in twenty-four hours, the argument in favor of
dominance of temperature through the reproductive factor would be
convincing. The writer has examined large numbers of publications
without finding definite discussion of this point. Apparently the
only eases in which the number of generations in a twenty-four hour
period has been accurately determined have shown what occurred
under special laboratory conditions only, and they do not tell what
occurs with a mixed population under natural conditions. Even so,
the published records of such studies deal almost entirely with animal*
types. Since the increase of numbers due simply to acceleration of
vital processes is sufficient to account for any probable influence of the
reproductive factor in this series, it is doubtless best to say that the
addition of a distinct generation during the twelve-hour period is
improbable.

It is also true that reproduction may be influenced by light. Some
organisms may be stimulated to greater reproductive capacity, some
to less. In the green organisms, with which we are now mainly con-
cerned, it may be seen that light, through acceleration of food manu-
facture, might cause increase of fission, due to increased availability
of energy producing and building materials. On the other hand, it
seems to be pretty well known that in higher algae and phanerogams
food manufacture is characteristic of day time, growth and repro-
duction of night, ie., the plant does not carry on all its funetions
equally well at the same time.

The gaseous content of the water would be mainly effective, under
ordinary conditions, through its influence on the irritability of the
organisms and through its more or less direct connection with their
feeding and respiration. A very slight difference in dissolved gases
would surely change the responses of some organisms to light and
other stimuli, but it is hard to determine the definite connection of
that fact with the conditions now under consideration. As Birge and
Juday have clearly shown, the physiology of plankton organisms can-
not be fully determined by tests under artificial conditions such as
those of the laboratory, e.g., the capacity of various animal forms for
meeting anaerobic conditions of the environment is vastly greater in

1920] Allen: Plankton of the San Joaquin River 123

natural bodies of water than it is in artificial cultures. In the pres-
ent instance it seems possible that the decline in numbers of certain
zooplanktonts toward midday might be due to negative phototropism
caused by supersaturation of water by oxygen liberated during photo-
synthesis by plants. But it might be due to negative phototropism
due to rising temperature, or to negative phototropism or positive
geotropism due to increasing agitation of the water, or to various
other factors or combinations of factors.

So far as green organisms are concerned, it may be readily under-
stood that photosynthetic and growth and reproductive processes
might all be accelerated by the presence of carbon dioxide with a
rising temperature and a considerable amount of sunlight (though
less than the maximum because of rough water). It is also true that
increase of oxygen formation might increase the buoyancy of the
plant cells so that larger numbers of them would be in the region of
water traversed by the net. This is especially probable in the pres-
ence of wind because any agitation of the shallow (two and one-half
meters) water would be an aid to buoyaney.

There is no possibility of segregating tidal from other influences
on our present information. So far as the currents, wind and tide,
and oscillations of the water are concerned, taken all together, they
might induce negative phototropism, or positive geotropism and thig-
motropism in the animals. They might also affect the green organisms
by aiding buoyaney and by increasing the cireulation of the water,
thus bringing more carbon dioxide to the absorbing surfaces and
rapidly removing oxygen and other waste products from such surfaces.

Perhaps enough has already been said about temperature, but it
will do no harm to recall that it affects flotation of organisms through
changes in viscosity, that it probably plays an important part in
reversal of tropisms under natural conditions, and that any change
either accelerates or retards all of the activities of the organisms.

For this series the influence of light cannot be segregated from
that of temperature since both are dependent on the sun’s rays. It
may be said, however, that hght plays more or less part in reversal,
or intensity of reversal, of tropisms of organisms, and that it is of
major importance in photosynthesis and thus in effect on the gas
content of the water.

So far as the other factors listed above are concerned, it is not
seen that they could be of appreciable influence in this period under
the conditions of variability recorded for the organisms and for the
general factors involved.

124 University of California Publications in Zoology [Vou 22

One point of general interest may be noted in plate 1, where it
appears from the volumetric graph that the total volume decreased
gradually to midday and increased again through the afternoon, but
that the net volume of plankton inereased fairly steadily throughout
the twelve hours. This is not what might be expected because the
wind and tide of the afternoon should, theoretically, stir the water
enough to increase the relative amount of silt. The unexpected silt
diminution might be due to collecting conditions, the stronger com-
bined current from wind and tide in the afternoon carrying away the
silt stirred up by impact of the drain cup cylinder upon the bottom.

CONCLUSION

In conclusion it may be said that the following points appear
distinetly from the present study:

1. San Joaquin waters are capable of supporting abundant plank-
ton, and they do so in the vicinity of Stockton.

2. The plankton of the sewage-laden Stockton Channel is distinetly
different from that of the river, the number and volume of its animal
forms being especially conspicuous as distinguished from the algal
dominants of the latter.

3. Temperature is, within certain limits, the determining factor
in seasonal distribution. This may be by direct retardation of growth
and reproduction in organisms, or by indirect influence through food
supply and gaseous content of water.

4. Water currents above a very moderate speed are distinctly in-
imical to plankton development.

5. The peculiar succession of rainy season and dry season has
resulted in an autumnal maximum of plankton about Stockton, a
condition directly contrary to that of vernal maxima recorded by
various observers in other localities.

6. Collections taken at intervals of one week or more do not furnish
a basis for accurate determination of plankton distribution through
the year. Daily collections properly taken would probably do so.

7. There is some evidence in favor of the idea that increase of
lunar light tends to the increase of plankton, especially chlorophyll
bearers.

8. There is evidence to show that fluctuations in amount of plank-
ton occur at various hours of the day.

1920] Allen: Plankton of the San Joaquin River 125

9. The abundant occurrence of Bacillaria paradoxa, generally
listed as a typical brackish water form, is notable. This seems to be
one case in which marked departure from a typical chemical environ-
ment has not visibly affected structure or behavior.

10. Lastly, it is necessary to emphasize the fact again that what-
ever fault or error there may be in this report is chargeable absolutely
to the writer. In some cases expert advice has not been followed after
being asked. On the other hand, there is the deepest obligation to the
persons already mentioned for advice and assistance.

ADDENDUM

Since writing the discussion of the series of plankton collections
of 1918 the statistics for the collections of 1914 and 1915 have been
compiled and examined. Inasmuch as weekly collections only were
taken in 1914 and 1915, and since two stations only were used in each
of these years, the records are much less comprehensive than those for
1913. On this account, and also beeause the 1914 and 1915 records
are essentially similar to those for 1913, it seems inadvisable to pre-
pare them for publication. The collections for 1914 and 1915 have
already been deposited with the Department of Zoology of the Uni-
versity of California and it is the writer’s intention to deposit the
manuscript records in the same place.

Transmitted August 15, 1918.

126

University of California Publications in Zoology

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrocKTON CHANNEL IN 1913

Spirillum
undula

Anabaena
sp.

Aphanocapsa
sp.

1,269,504
740,544
846,336
317,376
740,544
687,648

1,110,816
687,648
687,648
476,064
687,648

1,005,024

1,216,608
158,688

6,400
264,480
211,584

Gloeocapsa
conglomerata

899,232
158,688
3,200

Glococapsa
sp.

105,792
211,584

3,200
105,792
105,792

317,376

[Vot. 22

Gomphosphaera
aponinae

3,200

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockToN CHANNEL IN 1913—(Continued)

Spirillum Anabaena Aphanocapsa Gloeocapsa Glococapsa
undula sp. sp. conglomerata sp.
S200, weer. 3,200 105,792

Sipe emer! | gta ee 264,480

3,200 12,800 ites teres 528,960

105,792 BAN) 9 ceecbase Sree 317,376

3,200 158,688 12,800 3,200 370,272

3,200 6,400 PAW 584 secrete: 423,168

Portlets 211,584 105,792 eee tins 476,064

OGUZODe eee ee 105,792 899,232

PEO sa ise: 19,200 105,792 370,272

siatuuaheceeats 3,200 105,792 370,272

3,200 12,800 105,792 syaquunensives ‘ 634,752

Dalia 264/480 MOSMiG2°0 ieee 370,272

Se eset 264,480 105,792 ae one 370,272

GRA OOM iesrcceacees ; Lieieeantelt. 476,064

ees 24. 6,400 52806, dsc 740,544

ee deco 211,584 ema leVisemceens 423,168

Ee eee eee Ge400h “OR Svee oe. kates : 687,648

52,896 105,792 A AOR eee | coeeaees 952,128

acpccREECORS 6,400 52,896 ee : 740,544

eee ; 52,896 Be 528,960

DD QESOGI) D MeaecePeoscenss 423,168

52,896 158,688

ee 52,896

to cbetietnsciets 52,896

52,896 Bests Serene 158,688

TOS 7” eceeeesscceiem,) | eanceenedenseosole mate wedes 264,480

5S OSStmmeterencn Lltiwareetn) 6° Bescucseereres : 634,752

TOGO clidrtadsceccss, ebetpparcbeeecso F abbecetcmeenenee 423,168

52,896 ee Beis 264,480

23803820 es Siete s 634,752

URS GShe Geskeeeeteeaeee |b cacceoneccee OU Mi teceoacecacaioae 581,856

ZEB OGy We cretscreceto eee 317,376

476,064

ee 7 105,792

irate eyes 52,896

18,400 Mectevest rs badeseueaiseiaes 19,836

26,448 ites eee 66,120

26,448 Pee e averse reteencesesson 52,896

ere Sree oe is 13,224

800 eoteseesisst aieiaeees 39,672

800 Beene caettes eae eete ee sin se 46,284

ek a 39,672

Inactis tinctoria Merismopedium Microcystis Nostoe Oscillatoria
Agardh glaucum sp. sp. formosa

Gomphosphaera
aponinae

sp.

128 University of California Publications in Zoology [Vou. 22 |

TABLE 1,—ORGANISMS PER CuBIC METER IN PLANKTON OF
Stockton CHANNEL IN 1913—(Continued)

Inactis tinctoria Merismopedium Microcystis Nostoe Oscillatoria Oscillatoria
1913 Agardh glaucum sp. sp. formosa sp.

105,792
3,200
211,584
370,272
317,376
476,064
317,376
476,064
476,064
317,376
1,692,672
528,960
1,692,672
1,110,816
846,336
2,221,632
2'062,944
1,216,608

8/15 eaten ey - 476,064
a 423/168

8/23 211,584 37

8/27 264.480

8/31 211,584

9/ 2 3,226,656. _

9/ 6 CiST7E4S0 len ee, (gk een $99,232

1920] Allen: Plankton of the San Joaquin River 129

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockTON CHANNEL IN 1913—(Continued)

Inactis tinctoria Merismopedium Microeystis Nostoe Oscillatoria Oscillatoria
1913 Agardh glaucum sp. sp. formosa sp.
9/9 5,130,912 ; ste Pare ; 264,480 eee 899,232
9/13 5,501,184 are Sx x 846,336 ; nF 1,216,608
9/17 4,231,680 sexecbestasceds 317,376 ADS GSian vate 105,792
9/20 6,876,480 105,792 158,688 264,480 ees 1,110,816
9/24 6,559, 104 eee 476,064 Peace eae 370,272
9/27 4,337,472 52,896 52,896 iacseuscotscqars 740,544
10/ 1 2,433,216 1055792" a Leste ne Sas: 370,272
10/ 4 2,221,632 105,792 158,688 Berens 105,792
10/ 8 1,428,192 52,896 5 StGS Sarees eae 317,376
10/11 1,163,712 105,792 64.00 Ree: sche 105,792
10/15 1,216,608 6400) cate! 5 Rees 528,960
10/18 476,064 Benen We Niathetessaetie Bearer 105,792
10/22 846,336 G00 cece ee uatsRednee 370,272
10/26 105,792 5289608 eee a Potton see PRE neecaoad
10/29 317,376 sade aeteenes: 6,400 6,400 Prone One 211,584
Wye i 264,480 634,752 105,792 6,400 Ren eae), 52,896
11/5) rer acer 370,272 6,400 Pats )0)——— Goceanacts is 52,896
11/ 8 158,688 264,480 52,896 Sete ae eee 52,896
11/12 79,344 3,358,896 wes tee esha tise: ee 52,896
11/15 158,688 1,269,504 52,896 _........ es mame See
11/19 52,896 528,960 eater eee 3,200 ee rie 52,896
11/22 52,896 634,752 Be treme, | ht hae Ae ee ee 158,688
OW 2G en cectcet te 63452 eer es een AR en 0 Sere «Sn eenes
11/30 O5Si92 Geen MUGOOW™ SRA tscss sachet Merce | cesses
12-3 343,824 52,896
12/ 6 211,584 79,344
12/10 ORO OSI metres nor eee) es eee ss.e 26,448
12/14 S224 eas rece LOIRE Se ON Suess 33,060
12/17 238,032 33,060
12/20 105,792 39,672
12/24 33,060 13,224
12/27 OONER OME Mere a tt cecxas) WhacNyassdtene: 52,896
12/31 (Bee cestacsece tani Teeepoceeeters on mene reeerees 13,224
Oscillatoria Phormidium Stigonema Total Actinastrum Actinastrum
1913 tenuis spp. sp. Schizophyceae hantzschii hantzschii (large)
TP Sit A eee eee 13,224 VEO24> | Ree
1/8 1200) eee nse, HULDE ete
L/XL Saas Manes aires aes NE tea
TALUS) “eee een ae eae Be) whee
LAG) ae eee ere 400 SOOT) | GaSe. Vn Sie.
1/22 800 800 3,200 SOON oS ince
EPS ee aie 26,848 Ci AOr og Maes, ares RE
1/29 800 2,000
2/ 2 13,624 14,824
Dyfi) | | eeeeae aera es 400 2,800
2/ 8 39,672 40,472
2/12 Spe 26,448 26,448
2/15 26,448 370,272 396,720
SATE) > a eet 92,568 S4°168) a W600 peer a see
ZA ER ecer Pes 238,032 277,704
226 pace 238,032 EAS DA A een oe
3/1 3,200 79,344 85,744
3y/ Ge eee 158,688 GBA. eects © Coase eee
o/h ae OLS OGme samereet | “IOUS 976) svete: liprantehtece
Syl — sere eee ee Fong ceokcaicecdl lye DEORE LOMEECEE Oe MUR So EOS EIG PEON MERE Onc EE Ree
SH/AliG): PARES ee peer US SIGSSi wens ee Sa Cero | oe eee
3/19 1,600 238,032 318,976 O2:896: 5 verter

130 University of California Publications in Zoology [ Von, 22

TABLE 1,—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockToN CHANNEL IN 1913—(Continued)

Oscillatoria Phormidium Stigonema Total Actinastrum Actinastrum

1913 tenuis spp. sp. Schizophyceae hantzschii hantzschii (large)
3/23 1,600 Oro aeke | Weceastenitrsacas 80,944 52,896

BHO 8 | eevee Paredes DSS'OS2 ” eesctureehasacs 290,928

3/29 Ss LOD 792) = cree ccerncesce 110,592

4/2 Uso A ohotey wy mceeER Tere 163,488

4/5 185,136 ers taroe 239,632

4/9 158,688 naan atwaantes 175,688

4/13 6,400 aiteveapes ies 11,200

4/16 264,480 Deckert 322,176

4/19 j MS BIOSS 20) eecscarneeemne 165,088

BZ oxacteevteeccets 79,344 peep ao 185,136

4/26 9 3,200 mpi ebsrcU:Cebs 92,144

4/30 SEIDEL Dd cshecsstaeners secgadvanssackts 1,600

5/ 3 185,136 : : ee 267,680

5/ 7 1,600 14,400

5/11 52,896 160,288

5/14 105,792 320,576

5/17 317,376 323,776

5/21 3,200 379,872

5/24 370,272 488,864

5/27 105,792 323,776

5/31 158,688 168,288

(cy a ae 1,391,296

Clava once 884,736

6/11 3,200 859,136

6/16 3,200 461,568

6/18 105,792 859,136

6/21 3,200 1,226,208

6/25 3,200 1,886,560

6/28 211,584 2,436,416

7/3 sepeteeeaemenet 3,127,168

eS 12,800 1,559,584

TYSOY 9 | Sealectescestves 2,164,240

7/12 370,272 4,763,840

PUG © Secexecreeattns 4,919,328

7/19 eo 2,648,002

7/23 105,792 1,262,208

W/o Ree aie rere 2,750,602

SOM Varnes 1,543,584

8/ 2 3,200 703,648

BU/MGh ae OL cecestecnset pe omesits 1,114,016

8/9 15SGRen | Se ee 1,391,296

8/13 264,480 528,960 4,659,632

8/15 S200 eee eee 105,792 1,666,376

8/20 105,792 158,688 12,800 3,049,056

SY28) | decane 211,584 2,704,096

BY Tita, Me tenes 105,792 2'803,488

8/31 BiZ00N eeeeces cas 3,936,704

9/ 2 3,200 1,110,81 8,046,592

9/ 6 211,584 1,481,088 Ferme oee lie Shisaty

9/ 9 211,584 952,128 vogneusteenees 8,198,880 _..... Seas 3,200
9/13 3,200 528,960 Sites 8,806,832 3,200 6,400
OVilivae, bea SIVG76 sa Gakoest Got SDO Ua nee 6,400
9/20 eater 264,480 scisdeseatocts 9,580,576 211,584 6,400
9/24 52,896 1,163,712 Seeesepaereret: O'SOQ'G9G) | teewemeveess 105,792
QUA) BALA EE 158,688 Peveeacen 6,036,544 52,896 12,800
LUO) fod I wha Acer 423,168 statics 4,290,368 52,896 264,480
10/ 4 sdesoshive oreo 105,792 cotenh stentceaes 3,550,432 476,064
10/ 8 52,896 634,752 ; 3,332,448 158,688
10/11 6,400 581,856 2,446,016 158,688
10/15 476,064 105,792 2,545,408 158,688

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF

Oscillatoria
tenuis

Phormidium

spp.

26,448
13,224

Coelastrum
microporum

52,896
1,600
185,136

Pediastrum
boryanum

Stigonema
sp.

Pediastrum
duplex
6,612
400,
400
400,
1,200
4,800
400
19,836
13,224
2,400
5,600
6,400
11,200
92,568
26,448
79,344
3,200
12,800
12,800
6,400
22,400
132,240
9,600
16,000
9,600
6,400
79,344
6,400
6,400
16,000
1,600
3,200
16,000

Total

Schizophyceae

1,110,816
2,016,448
370,272
812,640
1,699,072
912,032
793,440
4,284,576
2/063, 144
1,008,224
1,388,496
689,248
347,024
641,152
297,328
158,052
260,668
364,060
264,880
89,156
225,608
145,464

Pediastrum
simplex

~~ 13,224
1,600
~ 1,600

6,400

~ 3,200

Stockton CHANNEL IN 1913—(Continued)

Actinastrum
hantzschii

Raphidium
polymorphum

~ 400

52,896
79,344

1,600
1,600
52,896
1,600
3,200

1,600
6,400
4,800
79,344
79,344
132,240
132,240

131

Actinastrum
hantzschii (large)

211,584
105,792
264,480
211,584
211,584

52,896

Richteriella
botryoides

800

3,200

“II -7
Tees

University of California Publications in Zoology

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
Stockton CHANNEL IN 1913—(Continued)

Coelastrum
microporum

211,584
476,064
211,584
105,792
211,584
211,584
105,792
211,584
423,168
634,752
528,960
634,752

1,005,024

2,221,632

2,697,696

3,544,032

1,163,712
793,440
264,480
476,064
423,168
317,376
158,688
211,584

52,896

158,688
12,800
211,584
158,688
52,896

52,896
264,480
79,344
28,800

Pediastrum
boryanum

6,400

3,200

6,400

~ 6,400

"3,200
12,800
3,200

“3,200
~~ 12,800

105,792
105,792

105,792
12,800
6,400
19,200
6,400
12,800
6,400
52,896
52,896
12,800
6,400

Pediastrum
duplex
6,400
3,200
6,400
105,792

6,400
19,200
6,400
12,800
6,400
12,800
32.000
158,688
25,600
6,400
158,688
317,376
370,272
793,440
476,064
1,005,024
1,269,504
793,440
740,544
634,752
793,440
740,544
476,064
264,480
793,440
423,168
317,376
211,584
476,064
105,792
105,792
634,752
634,752
687,648
476,064
423/168
740,544
1,851,360
793,440
952,128
1,110,816
1,798,464
2,010,048
1,533,984
476,064
740,544
793,440
$46,336
528,960
952,128
158,688
317,376
6,400
52,896
238,032

Ped

jastrum

simplex

52,896

~ 12,800

6,400

52,896

Raphidium
polymorphum

79,344
105,792
1,600
107,892
108,992
108,992
158,688
317,376
264,480
743,744
211,584
105,792
317,376
528,960
634,752
264,480
3,200
4,800
108,992
3,200
264,480
3,200
6,400
267,680
3,200
105,792
323,776
3,200
264,480
3,200
105,792
211,584
6,400
370,272
479,264
211,584
264.480
264,480
267,680
211,584
317,376
317,376
317,376
370,272
376,672
171,488

872,784
423,168
1£8,688
105,792

[ Vou. 22

Richteriella
botryoides

1920]

Allen: Plankton of the San Joaquin River 133

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
STocKTON CHANNEL IN 1913—(Continued)

Coelastrum
microporum

6,400

Scenedesmus
obliquus

2,591,904

Pediastrum
boryanum

6,400

Scenedesmus
quadricauda

2,539,008

Pediastrum
duplex
32,000
79,344
52,896
19,200
19,836
33,060

400
13,224
13,224
39,672
33,060

Schroederia
setigera

105,792

Pediastrum Raphidium Richteriella
simplex polymorphum botryoides

79,344

Selenastrum Stigeoclonium Ulothrix
bibraianum sp. sp.

134

1913
6/7
6/11
6/16
6/18
6/21
6/25
6/28
Uyes

.

or

‘
12
7/16
7/19
7/23
7/26
7/30
8/ 2
8/ 6
8/9
8/13
8/15
$/20
8/23
8/27
8/31
9/ 2
9/ 6
9/9
9/13
9/17
9/20
9/24
9/27
10/ 1
10/ 4
10/ 8
10/11
10/15
10/18
10/22
10/26
10/29
ib al
11/5
11/ 8
11/12
11/15
11/19
11/22
11/26
11/30
12/3
12/6
12/10
12/14
12/17
12/20
12/24
12/27
12/31

~I-J-I~
ne
o

University of California Publications in Zoology

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockTON CHANNEL IN 1913—(Continued)

Scenedesmus
obliquus
1,957,152
634,752
423,168
634,752
370,272
899,232

1,110,816
740,544
158,688
211,584
211,584
423,168
528,960
105,792
687,648
317,376
105,792
158,688

370,272
264,480
211,584
423/168
528,960
423,168
581,856
476,064
528,960
476,064
370,272
687,648
264,480
528,960
1,057,920
740,544
581,856
1,057,920
687,648
687,648
687,648
793,440
1,428,192
687,648
1,005,024
158,688
899,232
476,064
185,136
290,928
185,136
158,688
317,376
16,000
19,836
99,180
52,896
66,120
13,224
26,448
19,836

Scenedesmus
quadricauda
2,697,696
1,533,984
1,110,816
1,745,568
2,909,280
2'803,488
2,803,488
1,163,712
370,272
634,752
476,064
1,375,296
952,128
581,856
1,005,024
634,752
899,232
634,752
581,856
1,639,776
899,232
581,856
1,110,816
1,216,608
846,336
1,322,400
1,057,920
1,163,712
1,533,584
1,163,712
1,428,192
1/586,880
1,639,776
2,062,944
1,533,984
1,428,192
952,128
1,269,504
1,057,920
1,375,296
1,533,984
1,957,152
2,115,840
3,438,240
899,232
2,644,800
1,163,712
$46,336
925,680
370,272
661,200
185,136
396,720
112,404
211,584
132,240
178,528
66,120
99,180
132/240

Schroederia
setigera
317,376
158,688
3,200
264,480
264,480
105,792
105,792

52,896

264,480
105,792

6,400
105,792
317,376
317,376

1,600
1,600

13,224

400
26,448
13,224
13,224
19,836

Selenastrum
bibraianum

Stigeoclonium
sp.

[Vou. 22

Ulothrix
sp.

1920] Allen: Plankton of the San Joaquin River 135

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockTON CHANNEL IN 1913—(Continued)

Tota Asterionella Asterionella Amphiprora Bacillairia Cocconeis
1913 Chlorophyceae gracillima _— gracillima (large) alata paradoxa pediculus
1/5 19,836 TOUASCaE ee | Ne 6,612
1/8 1,200 OME SOSrn ote eteen | © Ueasrsaiees hod d enc coe errr eats
1/12 400 528,960 Berces te cnnect oe :
1/15 1,600 2,254,692 19,836 Joes cas
1/19 2,800 4,350,696 400 13,224 : :
1/22 40,660 740,544 SeaceSedeckcsses Rc arcrese 46,284
1/26 14,024 238,032 career Seiavccumene ten saesctiaaseee yy ( chiseadices
1/29 20086. Mowe oe a 1,600
2/ 2 14,824 WW OSIRAT2 5 ehcle, Eye knaee ae 6,400
2/5 32,448 985,188 Noreen tutes 13,224 sitter ees
2/ 8 11,200 1,044,696 5 ae
2/12 13,600 251,256 ber ee 52,896
2/15 117,792 859,560 speed oTily VA Peat ork: ot ae
2/19 242,032 1,097,592 Seecoeosaea ees 26,448
2/23 93,368 370,272 ay es 800 : ies SEX ;
2/26 219,584 4,496,616 Me oe Sees: 1,600
3/1 981544 2960) ese. 3,200 =
3/5 96,944 290,928 Sine :
By) ts) 27,200 132,240
3/12 68,896. is
3/15 169,040 370,272 =: hos 1,600
3/19 279,280 132,240 alist s5° 1,600
3/23 224,384 185,136 6,612 1600! Ueeetee | 6c eee
3/26 32,000 15SIGSQ) ee. eras
3/29 19,200 581,856 Lo cctetet ss ; tor ie 4
4/ 2 28,800 79,344 ee rraette ss : : 3,200
4/5 196,336 105,792 % on 1,600 3,200
4/9 96,944 105,792 26,448 1,600
ayAley 25,600 16,000 1,600 1,600 3,200
4/16 255,632 MO SYAG2MR Ureicss tec | chsseusssteets
4/19 133,840 OGrAdRin ees ee
4/23 375,072 382240) eee... :
4/26 290,080 132,240 Re tocce een
4/30 201,136 meee SS catelceoee &
5/ 3 113,792 1,600 ee
ant 145,040 502,512 Ree ccs seek Hy VenEtetaksea™ | aces
5/11 404,720 52,896 714,096 TGOON MRNA Le eek
5/14 432,768 105,792 264,480) vecease Bh Wieateer dees
5/17 147,392 211,584 SMON2) | eerere PEF Nese cd a eae ON a
5/21 713,248 211,584 3,200 steeds j
5/24 1,873,760 2S OO eee ; 3,200
5/27 2,026,048 158,688 3,200 158,688
5/31 5,834,560 See Moers Serene 3,200
6/ 3 5,829,760 158,688 3,200 Ea eee
6/ 7 5,116,416 LOS S92) Nees Pe
6/11 2,803,488 211,584 105,792 s PS
6/16 1,091,744 423,168 423,168 3,200
6/18 2,750,192 528,960 476,064 ; :
6/21 4,714,144 423,168 264,480 ¢ :
6/25 4,603,168 476,064 158,688 105,792
6/28 4,399,968 634,752 264,480 3,200
lifes 2,966,976 105,792 BerANO) — eoocas pete Bed tees | sacert i
Tiff LOZ O24 | eee ey) Mae aeeseeeeecs OFZ O0 eee R aortas 6 Sa eMaeee eet aee
7/9 2,131,840 cbscencacees Roly pe chncineiic. AOU meen okie
7/12 2,1385282 oa... ; Soc 3,200
7/16 3,080,768 aistetest ; Foca ree te Baten: : 12,800
7/19 2,362,624 —........ nee See ut 6,400 57,600
7/23 1,811,264 wtiecies ; Be Oe eineeea ie nd ; see
7/26 3,470,240 e oestraes é Pernt eee 3,200 CAN GY Ue eee oS

7/30 5920525 Ole meereersecace oes 3,200

136 University of California Publications in Zoology [Vou 22

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF
SrocktToN CHANNEL IN 1913—(Continued)

Total Asterionella Asterionella Amphiprora Bacillairia Cocconeis
1913 Chlorophyceae gracillima — gracillima (large) alata paradoxa pediculus
8/ 2 US TLOY S727 9k cree Wfrerisc ese Retass Mies 32,000
8/ 6 1,618,880 Manors deasacste SNe SEEM Morrie , 3,200
8/9 1,612,480 ss Séaiwad ) wagadesdueravess Fe ee Rese Ror svdeayesnn cares
8/13 3,338,948 S200) Weeeiceres, : Renee etisee 6,400
8/15 1,702,272 Pec bcs Pratdecseises : since sqinctoNwes 12,800
8/20 1,692,672 105,792 : s upees
8/23 3,024,672 apieeeserece Nosed borsawes say erawy 25,600
8/27 2,763,392 : Be eCCCE CPAP MC oe as 105,792
8/31 OenaRigas! «Sierras Lee Denk 25,600
9/ 2 4,048,296 Ratner es jiheauss scseny : <a ee 6,400
9/ 6 4,922,528 Susawasssaucaste easeestate sdvaezce , 6,400
9/9 5,557,280... : Watesssccets 3,200 6,400
9/13 6,410,016 Meee eases ees : Becsunee 3,200 6,400
9/17 3,414,944 Bren ae spavietees : 105,792 # sf
9/20 SHOSO 84, eebeessee. Re cere 52,896 52,896
9/24 4,481,664 Pee RADE hose ‘ 5 6,400
9/27 3,880,608 ebro 52,896 52,896
10/ 1 SMB OLa: |) - ceasesteseteress re 12,800
10/ 4 4,633,952 tssaseensestotcs 32,000
10/ 8 ANGGUO30) etek 6,400
10/11 4,680,448 eee M sch sctecs teacateeens sen
10/15 3,755,616 sei taveesiesst 52,896
10/18 2,591,904 Boome o Ee Sreces eS
10/22 3,312,352 Teese 105,792
10/26 S45 040) eeeenece. : 52,896
10/29 5,324,496 52,896 12,800
ilil// Al 4,191,584 LORIE TE 105,792
1/5 5,526,784 52,896 158,688
11/ 8 US5IM9GS: 9 evs. pateteteeesteseu re Upeeiceess ¢
11/12 5,211,856 1,600
11/15 2,809,888 adtacs Ttoevais. oy Sencatatssss?-0om IML lseentpsorepeeas
11/19 1,441,592 79,344 1,600
11/22 1,674,976 3,200 52,896
11/26 866,288 On eee 1,600
11/30 1,009,824 Susescnescesesss Erctess
WWE 746,944 1507-0560) ele OOO meeeeeetereye
12/ 6 491,216 1,401,744 1,600
12/10 213,584 614,916 OLE 400
12/14 372,272 198,360 390,108 39,672
12/17 239,632 185,136 400 13,224
12/20 331,800 105,792 Rae ree 26,448
12/24 121,016 85,956 Pee eee 13,224
12/27 299,140 59,508 socetstntsetsies 33,060
12/31 290,928 19,836 Won stapaats Rr asae
Cyclotella Cymatopleura Cymbella Cymbella Cymbella Cymbella
1913 spp. solea affinis eymbiformis parva sp.
W/e5 257,868 die hbnipsescs,. “cuakeetaee PS Meta) e osiico asic
1/ 8 106,592 Aen Serio Mae Sgesiice s ae eee a
1/12 SHUEY) 9” Reocnsroatbeeaee ers Gielen eapumetve Revers
1/15 793:440\ Ssecux :
1/19 TES 73656) weekeere
1/22 449,616 Pe eycetevsrstauy) U) Ssuduvcdsescasars) paekesstinnes
1/26 204,972 Pe raeeeeaaiaess
1/29 PAY Kic\ oh: Rae tee eee Serene TnL Soccasec
2/ 2 VBSiG88) Scclavelacen | Perec iac wl eReaeieat ie
2/5 357,048 atone:

2/ 8 304,152

1920] Allen: Plankton of the San Joaquin River 137

TABLE 1.—OrGANISMS PER CuBIC METER IN PLANKTON OF
SvTocKTON CHANNEL IN 1913—(Continued)

Cyclotella Cymatopleura Cymbella Cymbella Cymbella Cymbella
1913 spp. solea affinis cymbiformis parva sp.
2/12 740,544 GOO!) 1: MS ae,
2/15 1,150,488 800
2/19 eA OI Ada eee FR NTP EOO) | epmeteN | ou Xe
2/23 SSGlOO8 Bt eee tae eet ie, ok ae eee) | hvebacste ee
2/26 CL GADWATO!: Side seuetcceats acne ante a Mabierat ore samme te 3,200
3/ 1 5,210,256
3/5 5,659,872 ue
3/ 8 1,613,328 SELON a) ater eee ewan, vcceecesoee
3/12 GC TACOGR a tee en MOON Pe few | a)”
3/15 FATS: Gem soma SOS cat cee oh GRA a abl 10 A
3/19 2,168,736 ay) iii cteneietn en 3.04
3/23 2,724,144 3,200 1,600
3/26 1,163,712 ms
3/29 925,680 4
4/2 925,680 3,200
4/5 PAD U COE C Witernterty \csaiclsies ~~ aatehenties il GOO} Si esencecee:
4/9 GSC Osten Ute Sea keels 7 ae
4/13 SSD OAS ORS 2OOkne nett 5 Src oee te owe EE EE Nees
4/16 9,151,008
4/19 10,684,992
4/23 15,472,080
4/26 TOSCO ee Mae EA
4/30 18,116,880 PS Ss
5/ 3 20,391,408 3,200
By DONS S AGO ec IN deter Kc 2m
5/11 S27 GLOSS4 eee IKG0O)) Lasse.
5/14 60,248,544 IR ek Se ME
5/17 . 43,216,032 eerie) Mere ee :
5/21 36,022,176 tomteaen dave: f
5/24 SaOUSO0 oe a scl de un!
5/27 ASS 2788 () Ee Weert um erent | EES Soni
5/31 53,001,792 3,200
6/ 3 SPZSOVSOS Pe secre eres | eae keene
6/ 7 GOMOD IG4Sr issn aes Hehe
6/11 59,349,312 105,792 3,200 Rees
6/16 SOUS SS it epee ies a ee: 3,200
6/18 ADA ASS Shae) cate to) teeters ORAS eis
6/21 34,646,880 pi rectcrseivetchy, | Levene hiime | fcrehcesecstaee. | cecnaetelaeeees.! labaweueedees@ave
6/25 36,974,304 EAN! eyeseneeties of Saeco ;
6/28 51,362,016 wubeertervere vil | cessciecolesste 6,400
7/3 35,175,840 Po ee eeleredets: ;
af 5 14,281,920 eter Bite cose re
7/9 ESR RM aha ae ee eM ek Oe me Vereen
7/12 LO768;0382" ane. : te Weveonatsi © akties, | Meseeeneeteees
7/16 45,755,040
7/19 24,279,264 :
7/23 EAD OLD cee ; Boece arceen 6,400
7/26 LOS oe 3,200 ae
7/30 158168:S00N i es Safar eae Reta A ae hs ee
8/ 2 TAS ONG G25) aera ante bearer 2 See eee eee
8/ 6 ORB8IG56 © Lc. oe botatt ee aad die eae ne mere ee
8/ 9 10,790,784 eer ecicabtcen wet MeO eon ; TIO gE ONL Ree | Ay Seen
8/13 14229024 |.
8/15 6,770,688

8/20 12,113,184
8/23 14,440,608
8/27 20,047,584
8/31 PLAST
9/ 2 12M GGOSON Ee
9/ 6 1OATCGIOSO Meee ee

138 University of California Publications in Zoology [ Vou, 22

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrTocKTON CHANNEL IN 1913—(Continued)

Cyclotella Cymatopleura Cymbella Cymbella Cymbella Cymbella
1913 spp. solea affinis cymbiformis parva sp.
9/ 9 12,166,080
9/13 15,128,256
9/17 14,493,504
9/20 13,065,312
9/24 14,757,984
9/27 19,677,312
10/ 1 21,687,360
10/ 4 12/695,040
10/ 8 18,090,432
10/11 22'851,072
10/15 20,788,128
10/18 25/866,144
10/22 28,246,464
10/26 34,276,608
10/29 31,853,392
ny il 12,589,248

11/5 9,203,904
11/ 8 (GUD AP
11/12 11,240,400
11/15 7,722,816
11/19 7,061,616
11/22 7,697,968
11/26 6,692,944
11/30 6,876,480
12/ 3 6,955,824
12/ 6 4,522,608
12/10 1,970,376
12/14 2,281,140
12/17 2,499,336
12/20 2,737,368
12/24 1,283,128
12/27 2,876,220
12/31 1,838,136
Cymbella Diatom Diatoma Epithemia Fragillaria Fragillaria
1913 tumida unidentified vulgare ocellata capucina crotonensis
1/9)
1/8
1/12
1/15
1/19
1/22
1/26
1/29
2/2
2/5
2/8
2/12
2/15
2/19
2/23
2/26
3/1
3/0
3/8
3/12
3/15
3/19

1920]

Allen: Plankton of the San Joaquin River 139

TABLE 1—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockTon CHANNEL IN 1913—(Continued)

Cymbella Diatom Diatoma Epithemia Fragillaria Fragillaria
tumida unidentified vulgare ocellata capucina crotonensis
3,200 1,600

140 University of California Publications in Zoology [Vou. 22

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF
e SvTocKTON CHANNEL IN 1913—(Continued)

Cymbella Diatom Diatoma Epithemia Fragillaria Fragillaria
1913 tumida unidentified vulgare ocellata capucina crotonensis

Fragillaria Gomphonema Gomphonema Gyrosigma Gyrosigma Gyrosigma
1913 sp. constrictum sp. acuminatum kiitzingii scalproides

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
StockTON CHANNEL IN 1913—(Continued)

Fragillaria Gomphonema Gomphonema Gyrosigma Gyrosigma
sp. constrictum sp. acuminatum kiitzingii

6,400

141

Gyrosigma
scalproides

142

1913

11/26
11/30
12/ 3
12/ 6
12/10
12/14
12/17
12/20
12/24
12/27
12/31

University of California Publications in Zoology [ Vou. 22

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF
SrTocKTON CHANNEL IN 1913—(Continued)

Fragillaria
sp.

Melosira
granulata

19,836
26,448
2.400
13,224
26,448
1,322,400
33,060
125,628
72,732
204,972
132,240
145,464
304,152
542,184
119,016
476,064
343,824
132,240
264,480
158,688
793,440
1,031,472
793,440
476,064
502,512
502,512
132/240
634,752
952,128
72,784
528,960
2,274,528
3,702,720
449.616
449/616
343,824
343,824
581,856
1,269,504
1,163,712
1,005,024
1,375,296
317,376
634,752

Gomphonema
constrictum

Melosira
granulata A
(small)

317,376
211,584

~ 317,376
“238,032
1,600
ay, 52,896
1,600

211,584
158,688

105,792
317,376
105,792
105,792

Gomphonema
sp.

Melosira
varians

Gyrosigma Gyrosigma Gyrosigma
acuminatum kiitzingii scalproides

Navicula Navicula Navicula
affinis alpestris bacillum

Be 3,200 158,688
eich 1 ee Sok 105,792

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF

Melosira
granulata

528,960
370,272
1,322,400
1,375,296
634,752
2,062,944
7,617,024
3,067,968
1,005,024
1,481,088
2,697,696
1,586,880
2,168,736
1,428,192
2/962, 176
2,539,008
3,914,304
3,385,344
4,972,224
10,314,720
10,103,136
5,342,496
4,760,640
6,083,040
8,357,568
7,828,608
16,556,448
10,420,512
5,025,120
8,251,776
8,410,464
15,604,320
5,183,808
8,145,984
5,236,704
8,040,192
5,289,600
7,828,608
4,601,952
4,654,848
3,544,032
2,750,592
2,010,048
1,798,464
$99,232
1,137,264
1,005,024
740,544
978,576
1,137,264
1,084,368
1,745,568
1,057,920
350,436
257,868
337,212
370,272
271,092
588,468
925,680

Stockton CHANNEL IN 1913—(Continued)

Melosira
granulata A
(small)

Melosira Navicula
varians affinis
Sore 6.400
6,400
ee 52,896
CA00 0 eee

Navicula
alpestris

143

Navicula
bacillum

211,584
264,480
211,584

3,200
158,688
3,200
3,200

“3,200
105,792

~ 3,200

105,792
3,200
158,688
211,584
105,792
3,200
211,584
158,688
264,480
370,272
105,792
105,792
105,792
264,480
264,480
52,896
52,896
264,480
158,688
52,896
211,584

"52,896
264,480

144 University of California Publications in Zoology [ Vou. 22

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SvTocKTON CHANNEL IN 1913—(Continued)

Navicula Navicula Navicula Navicula Nitzschia Nitzschia

1913 dubia gracilis sp. viridis acicularis angularis
1 AS Oe, eR re teh A OME ce Se tacts
1/8 400
DM. asta Seer epee ys By eI O(n eee Sere
1/15 13,224
1/19 13,224
1/22 400
1/26 13,224
1/29 26,848
PHY) 19,836
aD) 13,224
2/8 27,248
2/12 26,448
2/15 26,448
2/19 120,616
2/23 9 tata | @ eeQOtan! — S800M aca aie ene :
2/26 3,200
3/1 107,392
OO: > atin eey | racket” "bo ROO LIE brett 5 eee e
3/ 8 3,200
3/12 3,200
3/15 1,600
3/19 79,344
3/23 1,600
3/26 79,344
3/29 1,600
4/2 79,344
AYTORL Samer eey | 0 Pe eareeees) | eek D SOGmere et tenet mn eee
4/9 105,792 eves
4/13 1,600 4,800
4/16 52,896 80,944
4/19 52,896 1,600
4/23 Fi Secs 211,584
4/26 52,896 185,136
4/30 79,344 264,480
rp st one Rann Bn eee Ane 79,344
5/7 1,600 317,376
D/A 52,896 290,928
5/14 105,792 952,128
5/17 158,688 1,533,984
5/21 3,200 2,644,800
5/24 264,480 5,289,600
SLE dae! a) ee teres 15,181,152
5/31 317,376 20,999,712
6/ 3 264,480 23,221,344
Cpat 3,200 11,055,264
6/11 3,200 11,108,160
6/16 105,792 13,752,960
6/18 211,584 19,624,416
6/21 370,272 14,969,568
6/25 158,688 11,901,600
6/28 211,584 11,108,160
W/f33 211,584 10,050,240
MOR ee! eerie woe 4,284,576
7/9 3,200 2,909,280
7/12 See ise, 866432
7/16 STO 2iae a) catetaeyn) | gmnece seater: 5,035,120
7/19 211,584 4,125,888
7/23 3,200 2,380,320
7/26 423,168 6,982,272
7/30 370,272 3,755,616

1920]

Allen: Plankton of the San Joaquin River 145

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF
SrocktoN CHANNEL IN 1913—(Continued)

Navicula Navicula Navicula Navicula Nitzschia Nitzschia

dubia gracilis sp. viridis acicularis angularis
6,400 ZOLASO! rissieectectees Se eee nen 3,385,344 weet ss
ee 158,688 a oe . 3,702,720 ;
3,200 264,480 SOD OZ een sees
seeavedars : 2,539,008 6,453,312
Ss J 952,128 1,586,880 RES 2
: : 1,269,504 634 7o2e) eee F
eee 1,110,816 1,005,024
3,200 793,440 2,539,008
1,822,400 4,760,640
1,163,712 5,236,704
3,200 846,336 3,596,928 |
846,336 2,115,840
476,064 1,904,256
370,272
a $46,336
rateeenerc 899,232
eee 476,064
oeesteneor ha 528,960
Si Ae eRe: 1,533,984
Leena 52,896 1,745,568
sines tae teas 264,480 1,904,256
158,688 2,062,944
aaa 158,688 2,221,632
52,896 52,896 2,062,944
ear 158,688 1,163,712
105,792 1,745,568
ets sae rdnees 1,322,400
WS sanc tt Sis 1,005,024
ie eee 1,322,400
52,896 3,173,760
See ae 1,851,360
79,344 1,719,120
105,792 2,062,944
79,344 2,036,496 2
105,792 2062944) he aweaeee
x Rees 1,163,712 Tee ee
Bass 105,792 1,666,224 3,200
ee ees 19,836 568,632 BEEP a ere rie
Poulet 46,284 416,556 -
ese 39,672 310,764
800 46,284 138,852
econ ieecree 46,284 119,016
Paevueave chances 66,120 145,464
Nee eeres 92,568 79,344
Nitzschia Nitzschia Nitzschia Pleurostauron Stauroneis Stephonodiscus
sigma sigmoidea vermicularis parvulum phoenicenteron sp.

146 University of California Publications in Zoology [Vor. 22

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SvTocKTON CHANNEL IN 1913—(Continued)

Nitzschia Nitzschia Nitzschia Pleurostauron Stauroneis Stephonodiscus
1913 sigma sigmoidea vermicularis parvulum phoenicenteron sp.

39,672
800
1,600
52.896
52,896
79,344
79,344
105,792
105,792

WNNeee
SNwmNoawoanwwoc

1920] Allen: Plankton of the San Joaquin River 147

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
Stockton CHANNEL IN 1913—(Continued)

Nitzschia Nitzschia Nitzschia Pleurostauron Stauroneis Stephonodiscus
1913 sigma sigmoidea vermicularis parvulum Phoenicenteron sp.
9/9 6,400
9/13 6,400
9/17 seAecetScAD
9/20 6,400
9/24 6,400
9/27 Bhetiesacs
10/ 1 atte
10/ 4 pct noe
10/ 8 19,200
10/11 Lf omnes
10/15 12,800
10/18 52,896
10/22 antes
10/26
10/29
iby al
1) *5
11/ 8
11/12 ae
11/15 6,400 syetsee
11/19 : : 52,896
11/22 1,600 sedvageede is
11/26 : ; 1,600 eee te cos : anes
11/30 105,792 ves Sey) eee en
12/ 3 G00) we: aan
12/ 6 Pe RM cae CVOTTOML Mui hen ua Mee te ame 2
12/10 UW vercedcertrrens ener eaters 33,060 ee eS iissacoceananere
12/14 19,836 RaCRSEECbO- ae cent 26448 i. : davusnseteetext
12/17 800. Lee ete seinen 19,836 eo i
12/20 SOOM eee A ME He ice 33,060 400
12/24 800 steereak , SesaneooaeC 400 Pere bics :
12/27 39,672 Ses coh Ee rere : 26,448 400
12/31 Pere § 800 DOVES eee
Surirella Synedra Synedra Total Closterium Closterium
1913 sp. radians ulna Bacillariaceae acerosum rostratum
WVMOMRE ewe mer Ta Waits 132,240 WG S 2) eres taceee
1/8 ine aid BR 59,508 452,016 Unediseese
1/12 66,120 915,656
1/15 138,852 3,275,140
1/19 ¢ 6,253,140 Saomacce :
1/22 2,858,572 400
1/26 774,404 400
Wem we 400) > betes 1,761,992 ideeGaptesstaaes jdvavatueasessas
DBO cette vents eee 152,076 Va54828). Stee: ; eee
PAS) 1,600 Meee 310,764 IRG4S 328i cercer: is iadeneedecors eae
2/8 SOOM. oa ease 132,240 1,668,624 1,600 cdieee sec eetcrt
Di), rere veers Re er ecrecic 370,272 1,656,200 PACA ROnR ICI
2/15 800 Secs eho e. 436,092 2,837,136 Sees
2/19 ASOOm © ieeedten 357,048 HOME On ss aeeereeenes oereceaee eee
2/23 3,200 al STO e | MIGOKOOl- atimeccs 9 2 Saullr
2/26 6,400 528,960 5,049,120 ee dents soceeasencdentes
By. eee ee F Pacer 581,856 6,834,784 ..... boateace ecoscenndees nets
3/ 5 3,200 sieteesotertetas 211,584 6,621,600 eee
Byfttshe! Mewes asere Geccede aovoteees 238,082 DBAQA24 abcess
3/12 3.200 re nets 158,688 3,206,608 Beet : coasters oh
3/15 Sscctosaceeeaeh me) ace tue eee 370,272 2,925,280 SSE | ascot
3/19 31000 ee ‘< gone Aeson) i Lane.

148

> Sy Nyeee
OAOwWonws

OT OT OT eH He HH HHH COS

SSMU
We TREN RR AIO OW

PAAAAHT

University of California Publications in Zoology [ Vou. 22

TABLE 1,—ORGANISMS PER CUBIC METER IN PLANKTON OF

Surirella
sp.

“12,800
3,200

3,200

6,400

SrocKkToN CHANNEL IN 1913—(Continued)

Synedra
radians

634,752
581,856
899,232
423.168
370,272
634,752

1,005,024

2:750,592
740,544
846,336
740,544

2,115,840

1,481,088
634,752
687,648
740,544
687,648
952,128

1,639,776

1,322,400

1,692,672

1,375,296

1,481,088

1,692,672

1,269,504

1,005,024

1,269,504

Synedra
ulna

396,720
105,792
264,480
370,272
185,136
79,344
396,720
158,688
714,096
132,240
132,240
581,856
290,928
132,240
687,648
2,010,048
687,648
423,168
1,957,152
1,110,816
846,336
1,375,296
1,110,816
899,232
1,110,816
476,064
1,692,672
2,856,384
1,533,984
423,168
476,064
423,168
634,792
317,376
528,960
687,648
528,960
423.168
423.168
528,960
2,062,944
1,005,024
952,128
1,375,296
1,375,296
1,322,400
2,539,008
1,057,920
1,533,984
687,648
$46,336
793,440
423,168
1,216,608
1,375,296
1,216,608
1,375,296
2,803,488
1,322,400
846,336

Total

Bacillariaceae

2,441,216
2'567,808
2,343,424
3,209,808
7,360,544
4,706,048

11,142,608

11,613,872

19,156,352

19,654,816

19,204,448

21,622,416

21,166,352

34,420,048

63,435,104

49,630,352

40,739,520

43,227,536

74,204,992

75,971,456

82,633,152

73,280, 160

72,582,912

55,939,872

66,023,808

51,797,984

53,755,136

74,338,080

50,161,408

20,001,088

17,204,000

24,761,728

58,002,816

31,801,600

16,675,040

29,637,760

23,495,424

23,354,240

18,159,328

20,966,016

39,059,648

21,613,568

21,815,552

31,965,184

39,987,680

29,588,064

36,761,024

27,590,816

25,372,384

26,731,680

27,194,944

37,535,264

30,415,200

36,841,216

22,379,712

30,908,768

33,574,464

35,802,496

35,512,416

37,370,176

Closterium Closterium
acerosum rostratum

105,792
211,584
423.168
19,200
105,792
6,400
105,792
211,584
264,480

1920] Allen: Plankton of the San Joaquin River 149

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockTon CHANNEL IN 1913—(Continued)

Surirella Synedra Synedra Total Closterium Closterium
1913 sp. radians ulna Bacillariaceae acerosum rostratum
10/26 6,400 846,336 528,960 40,861,312 _........ ee SEAR Sees.
10/29 12,800 793,440 793,440 38,450,896 Rae ei 105,792
11/1 105,792 740,544 211,584 17,098,208 derteveneneess chee ee
11/5 6,400 528,960 528,960 13,467,584 Sete a
11/ 8 6,400 634,752 264,480 11,233,152 Pe ae neeeneics are
11/12 1,600 1,243,056 476,064 17,409,184 mclavieenescesss 52,896
HAUS es okeccecoe : 158,688 LOS OZE 1019621212 neces eee Arts os
11/19 3,200 290,928 370,272 10,547,104 eevee 6,400
11/22 52,896 79,344 423,168 11,546,480 DOB ct 5. shea te:
11/26 3,200 132,240 211,584 10,301,072 SPE EERE 1,600
11/30 3,200 158,688 396,720 10,874,080 ere 1,600
PG) A) eeeccrtare : 79,344 925,680 12,398,464 2% us 1,600
12/ 6 6,400 1,600 158,688 9,041,168 See ee 3,200
UOVLOM GaN resto cases 39,672 113,204 3,751,992 1,600 Se ccna
12/14 800 52,896 191,784 3,948,552 ~—.... ee sont
12/17 400 33,060 125,628 3,598,928 800 400
12/20 4,000 52,896 370,272 3,976,400 Beer eee.
12/24 19,836 33,060" 138,852 2,071,744
12/27 46,284 46,284 621,528 4,627,788 Shasheces
12/31 26,448 26,448 509,124 SOUL OASH cer
Closterium Mougeotia Staurastrum Straurastrum Total Total
1913 sp. sp. A sp. Conjugatae Algae
1/ 5 1,197,572
1/ 8 456,016
1/12 916,456
1/15 3,277,140
1/19 6,283,188
1/22 2,923,468
1/26 816,476
1/29 1,785,028
2/2 1,484,476
2/ 5 1,963,576
2/ 8 1,721,896
2/12 1,697,048
2/15 3,354,048
2/19 3,979,576
2/23 2,138,664
2/26 5,513,136
3/1 7,021,272
3/ 5 6,930,128
3/ 8 2°694,400
3/12 3,275,504
3/15 3,307,504
3/19 4,551,808
3/23 4,572,420
3/26 2,764,144
3/29 2,697,600
4/2 2,537,312
4/5 3,652,176
4/9 7,633,176
4/13 4,742,848
4/16 11,720,416
4/19 11,912,800
4/23 19,719,760
4/26 20,040,240
4/30 19,407,184

150

University of California Publications in Zoology

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF
SrocKkToN CHANNEL IN 1913—(Continued)

Closterium Mougeotia
sp. sp.

Staurastrum
A

Straurastrum
sp.

Total
Conjugatae

3,200 3,200

ae 108,992

112,192

i 6,400

me 6,400 6,400

3,200 me 3.200

3,200 6400 eee re 9,600

oi 9,590

ee ee 6,400
CS SR Bee ii oe See eect 112,192
Rr ee 158,688 158,688 528,960
846,336 3,200 1,275,904

846,336 875,136

476064. eee 581,856

370272 ee 634,752

264,480 3,200 274,080

AZGOC4 eee 581,856

1745/5080 hn coe a 1,967,352

1,639,776 1057020) eee 2'013,248

264,480 G40) wees ees 274,080

AS niels 158,688 _...... Stale . See 165,088
Repo 158,688 Cd00y eles 270,880
ab Seen SORE ae ares 105,792
is 211,584 52,896 317,376

52,896 52,896 pe 112,192

ie 12,800 1,263,104

GA00) Manes 6,400

. eee 52,896 105,792 52,896 211,584
52.896 6,400 Kea 72,096

ae 105,792 52,896 211,584
52,896 52,896 165,088

alate 12,800 19,200

52,896 52,896

ow ias 52,896 158,688

12,800 12,800

rome 1,600 1,600

1,600 1,600 9,600

1,600 (ixe 1,600

abies 1,600 BE Ae lt 3,200

[Vou. 22

Total
Algae
22,003,888
21,327,392
34,986,656
64,188,448
50,101,520
41832.640
45,590,160
76,558,011
82:083.296
89,857,408
79,290,912
76,248,736
57,502,784
69,738,928
57,741,536
60,357,056
81,289,856
56,258,752
22'693,888
21/500,080
31,667,000
66,012,512
36,812,226
19,758,102
35,865,002
26,959,264
25,771,960
21,004,416
24.498,752
48,334,132
25,866,952
27,142/336
29,838,048
37,911,936
47,045,228
43,650,304
55,138,336
41,621,056
40,754,320
36,295,360
39,967,096
51,644,000
50,444,544
47,584,896
30,570,496
39,120,434
40,825,920
42,368.000
39,380,224
42,718,176
44,788,416
44'852)512
23,147,552
20,024,992
13,931,456
27,145,248
15,993,992
13,059,416
14,611,552
11,859,808

1920] Allen: Plankton of the San Joaquin River 151

TABLE 1,—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrocKTON CHANNEL IN 1913—(Continued)

Closterium Mougeotia Staurastrum Straurastrum Total Total
1913 sp. sp. A sp. Conjugatae Algae
11/30 See SROs Ce ees tied Boe 1,600 12,232,528
12/-3 Ser eceseteesstce arcceses : 65400) =e os 8,000 13,796,160
OG. ee ee nae Seteessavcnnsers Seas oan. <a 3,200 9,832,912
OMEN eee eA. eee per ercestep Fae se oh 21,336 4,144,964
12/14 aes igesenaeeviae es reeetiiesetivcte ab tye ert. see ; 4,602,940
12/17 poeReeeeeneee ncesertrece: DCR, eee : 1,200 4,230,268
ee): Se dessuaee : meeteatieaey | aves sivesiwes eenteocedetadem 4,599,528
OY 2AM Beers Sensex x 400 Se ae 400 2,282,716
12/27 AQON since: sae 400 5,153,036
(21/5 ent t mean ta uni nennen) MEL i 6 Nene ae, 4.127.276
Tota
Chlorophyll Ceratium Cercomonas Cercomonas Chlamydomonas Chromulina
1913 bearing hirundinella crassicauda sp. sp. sp.
1/5 LOgT® Weaeiclea” yi See ee ee a en
1/ 8 ADO ONG acetate No Suieciccstes, weita sess
1/12 GIE256) ee: saanienss é Ssacbasesteaccvsy Sxesssevseietaba (0 “eaeecass 5
1/15 A250 TMGe Bjoesecwsm) | Okeeeee Be ostascces seus : teres 945,516
1/19 USAR ASP rece Fives anki ye shuns WO ees deeciees : VeRO Senet 958,740
1/22 3,024,248 sgaesterecsecees Givecmeecetes spekauseetentene ; eearete ae 99,180
1/26 1,059,168 ape eare Sat Me hee 251,256
1/29 AOAC IYI)“ rerpeqncneteeane ; wees 271,092
2/ 2 Letsr2t, a 13,224
2/5 DAS MOSSe) Rte cean Lewis A |) ciscnena) | sien’ 152,076
2/ 8 PEON OU LEE eee creer ee catrncticnd . cceatincPae 462,840
2/12 WV O5O0MO4 ¢.2e ees 251,256
2/15 SOTA ee Colne | Ee, 317,376
2/19 5,542,136 1,481,088
2/23 2,528,560 277,704
2/26 6,268,080 687,648
3/ 1 7,113,336 423.168
Seo ROU OOT 2 eee fe) avsetiescnicl EMMA Geet : :
3/8 QUT OOGMEE Te ue | eta SF eG 1,600
3/12 roan OOM Me Giese, any. ee | | LaRue
3/15 SASCISU OTE Voie G | MCL ci vant a, 79,344
3/19 BGO Ode pene ee he § ON CN Oe ee
3/23 ARG SGD Mee ee ene Pees ee anc ee Sect
3/26 Sel SOS) 8 srsceeces se savgeaweaniscs ssdhewasheos. 158,688
3/29 3,179,968 sien cites See me serach ? NLS ee 423,168
4/ 2 2,697,600 styeassweacatone! Pere tie Jascucussesaszes A pov atessee 79,344
4/5 3,666,576 ecraertaaconr icbecrcaeece Sere ee TR 1,600
4/9 7,647,576 P se Rn eeeas ae , sient: Be es :
4/13 ANTE GIS ee eee 6 SAN 1,600
4/16 12,156,384 She Rovesi & sees i peeeree : ‘ 317,376
4/19 11,976,896 sascundceaeete ROR cote ae Bigsetadnesiine 0 Eos 52,896
4/23 20,939,568 eer re ae ee es = See eet eee 290,928
4/26 20,254,224 —........ hie cree Rercoscceear oe : 158,688
4/30 19,542,624 sWameeeedeteicteg | (a suasbyderedecr vies eiset we ehlne R ceks 132,240
5/ 3 22,294,816 Reece oe Preece ree eeeence note aN 79,344
byl a 21,378,688 __..... boetage stot di cecsaadnaeane Hae e 52,896
5/11 35,355,328 ROSES : Pcrcucecaers Pe Seen ay Pa 132,240
5/14 64,300,640 —........ wine Phe eet Pecetantaate Sa waitneheaete 105,792
5/17 50,683,376 __...... eS) peta te : eae. 317,376
§/21 42,053,824 ..... eanaiee is eae ne ee sohestic 5 mere osee
5/24 45,854,640 Sees ere issussagliaaaee
5/27 tA OSG: 97165 cess : seate acute 3,200 264,480
5/31 SOO ROCO mmm te (en nc ee Vee. ean 1,322,400
6/ 3 90,601,152 i... ee. Avieeereae! | eitterssvvaiees 0 re.satewent 105,792

University of California Publications in Zoology

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
STOCKTON CHANNEL IN 1913—(Continued)

Total
Chlorophyll
bearing

80,295,936
77,356,352
58,996,672
71,136,624
58,441,984
61,801,248
83,154,016
59,196,832
24,657,440
24,516,656
37,862,232
71,364,608
43,853,794
23,044,054
44,063,882
31,213,344
30,601,496
25,992,640
27,411,232
56,819,882
32,637,640
37,612,544
38,727,776
46,325,600
58,364,972
58,853,856
71,957,264
64,266,944
62,388,784
57,307,872
49,541,272
59,108,736
55,149,632
59,909,664
37,200,696
45,580,140
47,708,800
46,335,128
45,833,536
48,536,736
49,760,640
52,006,272
31,041,856
25,526,176
20,151,680
40,772,368
23,200,648
18,674,392
20,426,064
14,403,616
15,549,728
16,574,800
11,905,456

5,169,854

5,796,300

5,633,212

5,321,200

3,422,780

6,502,284

5,146,724

Ceratium
hirundinella

Cercomonas
crassicauda

Cercomonas
sp.

264,480
1,533,984
370,272
423'168
211,584
158,688

Chlamydomonas
sp.

"423,168
370,272

687,648
105,792

[ Von. 22

Chromulina
sp.

105,792
211,584
899,232
634,752
370,272
581,856
740,544
1,428,192
634,752
2,486,112
4,919,328
5,183,808
6,929,376
3,173,760
7,299,648
3,279,552
3,967,200
3,226,656
1,481,088
6,347,520
4,231,680
6,876,480
6,770,688
5,289,600
5,554,080
7,722,816
10,579,200
11,531,328
13,224,000
17,825,952
5,977,248

5,977,248
12,906,624
6,347,520

2,856,384
2/221 ,632
1,957,152
806,664
859,560
932,292
621,528
932,292
971,964
641,364

1920] Allen: Plankton of the San Joaquin River 153

TABLE 1.—OrRGANISMS PER CuBIc METER IN PLANKTON OF
StockTON CHANNEL IN 1913—(Continued)

Cryptomonas Dinobryon Eudorina Euglena Euglena Flagellate
1913 sp. sertularia elegans deses viridis unidentified

BOR hee 105,792
se Pate 3,200
ee 105,792

Lees Save 158,688

Prec 6,400 senses:
porecccasn OS NIO2R Werseeeeeeeees
eepeteneneeeness 370,272 vastdateseeusees
remeeretrcn 423,168 eer

154

University of California Publications in Zoology [Von 22

TABLE 1,—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockToN CHANNEL IN 1913—(Continued)

Cryptomonas Dinobryon Eudorina Euglena Euglena Flagellate
sp. sertularia elegans deses viridis unidentified

105,792

476,064

105,792
158,688
264,480
105,792

476,064 211,584
158,688 _.... 158,688
1051702 eee BYO2m apes 52.896

hens 105,792
105,792

264,480
105,792
79,344
185,136
185,136
132,240
52,896
1,600
66,120
400
99,180
26As Ma eaactites | paotniem
BOSSES. eee 800
665120) eee 800
TAY Meu eh ee oe 400

Hemidinium Mallomonas Pandorina Peridinium Peridinium Phacus
nasutum sp. morum einctum sp. pleuronectes

ae Detect 26,448

1920]

Allen: Plankton of the San Joaquin River 155

TABLE 1—OrGANISMS PER CuBIc METER IN PLANKTON OF

Hemidinium
nasutum

952,128
1,745,568
2,168,736
1,533,984
2/380,320
4,125,888
4,178,784
4,866,432

SrocKTON CHANNEL IN 1913—(Continued)

Mallomonas Pandorina Peridinium Peridinium Phacus
sp. morum cinetum sp. pleuronectes

ane ~ 158,688
sg Scat Tn en 211,584

~ 158,688

317,376

Bl05 7021 oe ee

et es

156

University of California Publications in Zoology

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF

Hemidinium
nasutum

9,679,968
7,617,024
2,221,632
2,433,216
528,960
3,861,408
2,168,736
528,960
317,376
1,481,088
264,480
211,584

SrockToN CHANNEL IN 1913—(Continued)

Mallomonas
sp.

Pandorina
morum

Platydorina
caudata

Pleodorina
californica

Pteromonas
sp.

Peridinium
einctum

105,792
105,792

Spondylomorum
quarternarium

Peridinium

Synura
uvella

[VoL. 22

Phacus
pleuronectes

211,584

52,896
370,272
238,032

Trachelomonas
euchlora

1920] Allen: Plankton of the San Joaquin River 157

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockTON CHANNEL IN 1913—(Continued)

Platydorina Pleodorina Pteromonas Spondylomorum Synura Trachelomonas
1913 caudata californica sp. quarternarium uvella euchlora

105,792
1,600
476,064
52,896
1,600

Ves}2001, Oa
TESOS8- fan

158 University of California Publications in Zoology [Vou, 22

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF
STOCKTON CHANNEL IN 1913—(Continued)

Platydorina Pleodorina Pteromonas Spondylomorum Synura Trachelomonas
1913 caudata californica sp. quarternarium uvella euchlora
10/18
10/22
10/26
10/29
11/ 1
11/5
11/ 8
11/12
11/15
11/19
11/22
11/26
11/30
12/3
12/ 6
12/10
12/14
12/17
12/20
12/24
12/27
12/31
Trachelomonas Trachelomonas Total Amoeba Amoeba Arcella
1913 sp. volvocina Mastigophora proteus radiosa vulgaris
LT peas RE PE le ke
1/8 sarees
11/17 ete em ieee te tet :
1/15 19,836
1/19 39,672
1/22 400
1/26 19,836
1/29 19,836
2/ 2 400
Zio rte Tease
2/ 8 39,672
2/12 800
2/15 800
2/19 As ceeerceesetes
2/23 39,672 389,896
2/26 1,600 754,944
ofa 52,896 493,664
3/ 5 79,344 88,944
3/ 8 52,896 60,896
3/12 52,896 60,896
3/15 79,344 181,088
3/19 52,896 57,696
3/23 1,600 113,792
3/26 52,896 353,424
3/29 waaentacaad 482,368
4/2 160,288
4/5 14,400
4/9 PA ers 14,400
4/13 Revonieavasatoes Base ececupecnse 12,800
4/16 ; sieved ‘ 435,968
AO Skekaee rs 1,600 64,096
4/23 370,272 1,219,808

4/26 a eS Baie fete 217,984

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockToN CHANNEL IN 1913—(Continued)

Trachelomonas Trachelomonas

sp.

volvocina

105,792

79,344
264,480
211,584
105,792
264,480
211,584
317,376
687,648
793,440
423,168
264,480
158,688
687,648

~ 3,200
105,792

~ 105,792
105,792

158,688
317,376

740,544
476,064
211,584
158,688
502,512
476,064
158,688
158,688

Total
Mastigophora
135,440
290,928
52,896
370,272
112,192
581,856
221,184
264,480
532,160
1,540,384
746,944
1,005,024
1,110,816
1,497,088
1,503,488
700,448
1,447,392
1,867,360
2,941,280
2,069,344
3,016,576
6,195,232
5,352,096
7,041,568
3,285,952
8,198,880
4.244.480
4,832,736
4,988,224
2,912,480
8,485,750
6,780,288
10,473,408
8,892,928
8,519,456
11,319,744
15,203,552
16,824,128
22,645,888
21,634,464
21,012,512
9,574,176
7,464,736
14,705,088
12,377,664
6,630,200
6,459,712
6,935,776
4,020,024
6,453,312
5,818,560
5,025,120

13,865,152
7,365,344
5,667,872
5,814,512

Amoeba Amoeba
proteus radiosa
eee 1,600

1,600 79,344

he. 1,600

wine 1,600

3,200

ew Bees 3,200
sedge te
~ 158,688
105,792

3,200

etaveatesai eis i 156 688

159

Arcella
vulgaris

160

University of California Publications in Zoology

TABLE 1,—ORGANISMS PER CuBIC METER IN PLANKTON OF

SrockToN CHANNEL IN 1913—(Continued)

Trachelomonas Trachelomonas
sp. volvocina
211,584
264,480
449,616
105,792
112,404
330,600
370,272
59,508
132,240
297,540
284,316

Difflugia Difflugia
corona pyriformis

13,224

1,600

211,584
423,168
211,584
317,376
952,128
i Cee 370,272
Reyer 1,322,400

Total
Mastigophora
2,543,808
3,317,200
2,780,240
2,072,544
1,024,860
1,219,808
1,429,392

748,120
1,140,464
1,349,648
1,039,284

Hyalodiscus
sp.

Amoeba
proteus

Hyalosphenia
cuneata

Amoeba
radiosa

[Von. 22

Arcella
vulgaris

Hyalosphenia
papilio

Microgromia
socialis

1920]

Allen: Plankton of the San Joaquin River 161

TABLE 1.—ORGANISMS Per Cubic METER IN PLANKTON OF
Stockton CHANNEL IN 1913—(Continued)

Difflugia Difflugia Hyalodiscus Hyalosphenia Hyalosphenia Microgromia
corona pyriformis sp. cuneata papilio socialis
OR eesaicerecrac boc bocees ore 3,200 3,200
ailsts}(atstsy) |" Gecesecerererees : pec rtg-0 3,200
423,168 entacar enews sekenetawess Sites ;
158,688 stent : eae eae 3,200
UIC PEAT Vis eeccttensecceseae m Meteoad: peceecno oer ae 3,200
581,856 ; Ale
581,856
105,792
211,584

264,480

te “3,200
3,200

264,480

~ 105,792
~ "3,200

3,200
Sal 105,792
_ 3,200 e
6,400 3,200
coe aes 3,200
a 6,400 BOW, lenses
a Were eee S00 eee ie 58
oe eS PD ee) (Ee ene 105,792
set, LS ones TSSGSS eae ee ee ee 52,896
cee oh oa ed as 10507020. eee ny fees 52,896
NE ii es BOOP eee) cuatro" yeaa
Laon eee Se re eR OOO eae 5 oe ipa 211,584
om: 264,480
< Se ee are en 211,584
a Ske a ee ED 264,480
oe 1059702) | fee 52,896
634,752... 211,584
aide ed ee oe 3700272 ee Ae ee ORE IG Se, =
Re, ie. SOIROO MIRAE Gas Noms cee 211,584
Me ee at Kalle once 52,896
ae 105,792
3,200 TI DOLO MRIS Cee nce aA vi
TG GGIN” aa eee ere ce a
3,200 1600.) > 2a 1,600
SOO: eM Ce 8 eee sete
400
7) eS eee

162 University of California Publications in Zoology [Vou. 22

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
STocKTON CHANNEL IN 1913—(Continued)

Nebela Trinema Total si Heterophrys Heterophrys
1913 sp. sp. Rhizopoda sol. fockei sp.
E/E iecccoec een Wes sees 13,224
1/8 am Caches Brawler eae
1) AIO) aks Seen
1/15
1/19
1/22
1/26
1/29
2/ 2
2/5
2/8
2/12
2/15
2/19
2/23
2/26
3/ 1
3/ 5
3/ 8
3/12
3/15
3/19
3/23
3/26
3/29
4/ 2
4/5
4/9
4/13
4/16
4/19
4/23
4/26 238,032
4/30 107,392
ys} 82,844
(ay/¢f 3,200
5/11 161,888
5/14 211,584
5/17 4291568
6/21 214,784
5/24 317,376
5/27 955,328
5/31 781,856
6/ 3 1,533,984
6/ 7 746,944
6/11 165,088
6/16 423,168
6/18 161,888
6/21 22,400
6/25 581,856
6/28 581,856
uf 3 105,792
7/5 224,384
7/9 270,880
7/12 3,200
7/16 112,192
7/19 6,400
7/23 105,792
7/26 267,680
UPON ce pcttectd. site er panies rere 3,200

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
StrockToN CHANNEL IN 1913—(Continued)

~ 105,792
105,792

Nuclearia
simplex

Trinema
sp.

1,600

Pinaciophora

fluviatilis

Total
Rhizopoda

370,272
1,163,712
581,856
858,524
381,856
323,776

137,040

Raphidiophrys

elegans

Actinophrys
sol.

~ 105,792
581,856
52,896

Total
Heliozoa

Heterophrys
fockei
528,960
105,792
317,376
105,792
211,584

~ 3,200
3/200

~ 211,584
211,584

158,688
264,480
158,688
6,400
52,896
52,896
105,792

Askenasia
elegans

~ 400

800,
1,600

163

Heterophrys
sp.

Bursaria
sp.

ae

164 University of California Publications in Zoology [Vou, 22

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockTON CHANNEL IN 1913—(Continued)

Nuclearia Pinaciophora Raphidiophrys Total Askenasia Bursaria
1913 simplex fluviatilis elegans Heliozoa elegans sp.
7H Eee Set OR RNR Shumate sisnsimy OSE
2/15 Aes
PYAR AS RR orn See icine
7A fe 5 ean eyes sc) 0) RRP ee PI ante 6 cry
PPL Pest ten See eeetey hy aortic etre:
OhaL seleateelea) mlechvseneessssEe. |e lmuzect RR CA Mey oy ohms
3/ 5 Petro, | Waa mote
3/ 8 et A MmTrOe Onin Le oR) Ter
3/12 Sree PRCT er ere COED ’
SHS pear me 1,600
3/19 TIAGO, kde eect eee ee
OLY ME LieTIe RS
LAGI ry ener svt en MPR E re MOREE Ss oy ll eager
3/29 D200 9 aecshvatekecs 0 az .ceee oe
4/2 Re ee RR age mnt h © 6 tenes
4/5 Seshseeveoe al Ductedeveevpusacsuol Pew (nabecdccectecetey
4/9 TGOOn a tec cca oc eee meee
4/13 5218961 Meese, othe ee
4/16 TGOO! oe DiectidoscrBie! » Aaadtscit ee a ees
SO Te ae NL on eet Lae ee
4/23 79,344 fcr Eee
4/26 52,896 52,896 52,896
4/30 132,240 132,240
5/ 3 2k See ve :
S/N 211,584 211,584
5/11 158,688 158,688
5/14 3,200 3,200
DY ia kes cotr tees Woah | eRe Reece
5/21 1,216,608 1,216,608
YQ & Becevetcinaiel a Ul atari ees wel ee :
5/27 ie
5/31 3,200 3,200
6/ 3 Pee ct eee ,
Cai, 740,544 740,544
6/11 1,005,024 1,005,024
(yA: |) Peereenacctoee SES ove 1,322,400 1,322,400
6/18 Acdece Pe eee 158,688 158,688
Gy iby e eeres cent) Mm) cotonkrerae 264,480 264,480
C/ 25m eter iabgeeseneaeat 1,851,360 1,851,360
G/28e 1 oeatirens Reaesrrcarnrt 740,544 740,544
UL Bie” eRe Nica aS vez te 793,440 793,440
7/5 6,400 Cieoorsnceuaees 528,960 528,960
TE Qt snte 846,336 846,336
7/12 niles 158,688 158,688
7/16 3,200 528,960 528,960
OVAL OD Grevichestrn ce 370,272 370,272
7/23 = ou ameter 317,376 317,376
UU Ps che a erent ee 370,272 370,272
7/30 Paver Netietiiviienes 370,272 415,072
SHED eae cue 1,269,504 1,798,464
8/ 6 Secret oy eee: 264,480 370,272
8/9 pea acissasere sinesweeVeneeees 423,168 740,544
8/13 158,688 Rhiscesseeesnee 1,745,568 1,851,360
8/15 fearee. tetas Bee eM: 528,960 952,128
SLO a ceazener rece i Stee ; 317,376 317,376
YP Me checcerce- fol Lienert 1,586,880 1,590,080
8/27 OpUOM © Oe 2. meee: : 105,792 108,992
VGH soto ern a, We eer 687,648 687,648
9/ 2 3,200 Asgesguvssesees 211,584 211,584

1920]

Allen: Plankton of the San Joaquin River

TABLE 1—ORGANISMS PER CUBIC METER IN PLANKTON OF
SrocKkTON CHANNEL IN 1913—(Continued)

Nuclearia
simplex

Chilodon
sp.

Pinaciophora
fluviatilis

~ 423,168

52,896
476,064
370,272
317,376
370,272
476,064

105,792

Ciliate

unidentified

Raphidiophrys

elegans

“3,200

~ 211,584

4,549,056
1,428,192
3,702,720
1,745,568
819,888
1,600
1,600
396,720
1,600
52.896

400

Coleps
hirtus

Total
Heliozoa

3,200

211,584
211,584
211,584
52,896
264,480
158,688
429,568
105,792
528,960
581,856
1,110,816
423/168
476,064
4,654,848
1,428,192
3,782,064
1,798,464
819,888
1,600
54,496
398,320
1,600
52,896

400

Colpoda
sp.

400

Askenasia
elegans

Cyclidium
sp.

Bursaria
sp.

Didinium
nasutum

166

University of California Publications in Zoology

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
STocKTON CHANNEL IN 1913—(Continued)
Chilodon Ciliate Coleps Colpoda Cyclidium
sp. unidentified hirtus sp. sp.
Se eters 132,240

158,688
105,792
_ 105,792
264,480
158,688
158,688
317,376
476,064

3,200
264,480
105,792
105,792
158,688

52,896
211,584

[ VoL, 22

Didinium
nasutum

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CuBIC MSTER IN PLANKTON OF
SrockToN CHANNEL IN 1913—(Continued)

Chilodon
sp.

Enchelys
sp.

1,600

Ciliate

unidentified

158,688
145,464
132,240
132,240
317,376
6,400
158,688
79,344
158,688
370,272
264,480
79,344
35,200
70,400
211,584
132,240
25,600

6,400

1,600

Coleps
hirtus

264,480
105,792

119,016
66,120
19,836

400

Euplotes
patella

800

52,896
52,896
66,120
105,792
52,896

3,200
1,600
12,800
9,600

3,200
9,600

Col;

poda Cyclidium

sp. sp.

158,688

Frontonia Halteria
sp. grandinella

52,896
46,284
800
800
4,800
1,600
4,800
1,600
3,200
3,200
105,792
52,896
3,200

167

Didinium
nasutum

32,000
19,200
1,600

~~ 3,200

Hastatella
radians

6,400
9,600
9,600
105,792
1,600

168

University of California Publications in Zoology

TV'ABLE 1.—ORGANISMS PrER CuBIC METER IN PLANKTON OF
SrocKkTON CHANNEL IN 1913—(Continued)

Enchelys Euplotes Euplotes Frontonia Halteria
sp. harpa patella sp. grandinella

[Vou 22

Hastatella
radians

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF

StocKToN CHANNEL IN 1913—(Continued)

Enchelys Euplotes Euplotes Frontonia
sp. harpa patella sp.

Holophrya Loxophyllum Paramecium Paramecium
sp. sp. aurelia bursaria

Halteria
grandinella

Paramecium
caudatum

169

Hastatella
radians

Pleuronema
sp.

290,928
211,584
3,200
185,136
79,344
211,584
105,792
211,584
105,792
132,240
79,344
105,792
1,005,024
105,792
264,480

170 University of California Publications in Zoology [ Vou. 22

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF
SrockToN CHANNEL IN 1913—(Continued)

Holophrya Loxophyllum Paramecium Paramecium Paramecium Pleuronema

1913 sp. sp. aurelia bursaria caudatum sp.
6/ 7 PS Sy. J bktteeneress? : Les teres SUS IRENA, adigectevaks EEE
6/11 158,688 eee TN Aaecvascenesstach. | meaner ie) Stoseoreroe
6/16 3,200 » a” Onna
6/18 3,200
6/21 3,200
6/25 3,200
6/28 158,688
133 3,200
U/5 158,688
7/9 211,584
7/12 3,200
7/16 6,400
UO Resterereeboss
7/23 BNE ee
7/26 211,584
7/30 105,792
8/ 2 105,792
8/ 6 105,792
8/9 740,544
8/13 634,752
8/15 317,376
8/20 105,792
8/23 158,688
8/27 105,792
8/31 3,200
9/ 2 3,200
9/ 6 317,376
9/ 9 211,584
9/13 error
9/17 3,200
9/20 370,272
9/24 158,688
9/27 211,584
10/ 1 211,584
10/ 4 52,896
10/ 8 423,168
10/11 105,792
10/15 105,792
10/18 105,792
10/22 370,272
10/26 52,896
10/29 Peed ptr
11/1 52,896
L/S 52,896
11/ 8 52,896
11/12 52,896
TANS) Re
11/19 105,792
11/22 79,344
11/26 Scien tees
11/30 238,032
12/ 3 79,344
12/ 6 1,600
12/10 er eee
12/14
12/17 13,224
12/20 72,732
12/24 13,224
12/27 59,508
12/31 39,672

1920] Allen: Plankton of the San Joaquin River 171
TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
Stockton CHANNEL IN 1913—(Continued)

Prorodon Stentor Stentor Tintinnidium Trachelius Trichodina
1913 sp. coeruleus niger fluviatile ovum pediculus
Wf 5 800. GiG12 ee
1/8 400 1,200
1/12 1,200 2,000
1/15 33,060 26,448
1/19 52,896 39,672
1/22 72,732 112,404
1/26 132,240 515,736
1/29 26,448 158,688
Pa GA ae ee EY ENR 33,060
2/5 400 39,672
Di ROM Scene ak See ae 11,200
2/12 1,600 66,120
2/15 8,000 39,672 ;
2/19 800. 52,896 3,200
2/23 1,600 105,792 1,600
2/26 3200 Mee Laue 67,200 6,400
3/ 1 105,792 12,800 158,688 9,600
Si) i! emteeeney Meeeeees 185,136 ‘
3/ 8 3,200 ie og Mane 158,688 1,600
3/12 oe) 105,792 608,304 ;
3/15 UENO) cereeedreneniace 35,200 ;
3/19 6400" ~ eka ees 211,584 3,200
3/23 3,200 6,400 238,032 ee
3/26 oe ga Bee teases US POLL) Ma sen tn ee eR eRens A Men pee Se
3/29 ILO) cescacos : 79,344 3,200
4/ 2 ee 6,400 22 AQOE” Sarcssiienl carkeveeaeiss Sucsuneee
4/5 6,400 6,400 PAOD) (0 eerie tere) Pants Venom mre ane eee Ae
UNOS eee a 9,600 S| Seana terrmeesce lmareenmaostan
4/13 GA00F* oeees. a GeO 0 ewe ere ees ee a meee
4/16 oe eee 105,792
Ci G)y 0 Sento te ee er ATMGOOM ON cictesttttiti ey. baste 0 kisser
4/23 6,400 SAPAOO pe coes cence Me ace eenee| O,_aimetszeeetere
4/26 : 3,200 211,584
4/30 3,200 6 19,200
5/ 3 eer 6,400 TOSS OZ MEM Ce eR ee eee
Ey) 7 ce 25,600
5/11 105,792
5/14 Re RE ne are Wi A nen es en ees ee
5/17 211,584
5/21 ae ota "so RAE Ss, Leer ee A
DY Ame Ee | Gee oA re 6,400
5/27 ind’ — eR Arcee, Ranma enh at ead er ce oe
5/31
6/ 3
6/ 7
6/11
6/16
6/18
6/21
6/25
6/28
7/3
Ut ®
7/9
7/12
7/16
7/19
7/23
7/26

University of California Publications in Zoology

[ Vou, 22

TABLE 1,—ORGANISMS PER CUBIC METER IN PLANKTON OF

Prorodon
sp.

~ 52,896
52,896

~ 1,600
33,060

Vorticella
longifilum

Stentor
coeruleus

Vorticella
sp.

Stentor
niger

39,672

Total
Ciliata
7,412
1.600
4,000
63,108
132,040
250,832
899,632
391,308
53,484
103,180
85,272
284104

Tintinnidium

StockToN CHANNEL IN 1913—(Continued)

Trichodina
pediculus

Trachelius
fluviatile ovum

~ 264,480
25,600
211,584

158,688
211,584
12800) 0c eee oe Se

6400" 0. ae) ee
I5St688'. ace

~ 6,400
105,792

© 158,688 <n

Acineta Podophrya

Sphaerophrya
Sp. sp sp.

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—OrGANISMS PER CuBIc METER IN PLANKTON OF

Vorticella
longifilum

1,600

SrockToN CHANNEL IN 1913—(Continued)

Vorticella
sp.

687,648
396,720
396,720

1,533,984

1,692,672
740,544

1,428,192

1,163,712

1,322,400

1,428,192

2,433,216

1,745,568

1,798,464

2'591,904

3,596,928

1,851,360

2/062,944

1,692,672

2'644,800
476,064
740,544

1,110,816

1,057,920
476,064

1,269,504
899,232

1,639,776
634,752
687,648

2,168,736

1,375,296

1,586,880
793,440
740,544

1,851,360
899,232
899,232
634,752

Total
Ciliata
649,152
272,856

1,702,272
2,806,688

687,648

743,744
1,116,216
1,057,920

476,064
1,487,488
1,117,216
1,748,768

743,744
1,428,192
2,968,576
2,128,640

Acineta
sp.

Podophrya
sp.

173

Sphaerophrya
sp.

174 University of California Publications in Zoology [VoL 22

TABLE 1—ORGANISMS PER CuBIC MEYER IN PLANKTON OF
Stockton CHANNEL IN 1913—(Continued)

Vorticella Vorticella Total Acineta Podophrya Sphaerophrya
: sp.

longifilum sp. Ciliata sp. sp

952,128 1,242,208
1,005,024 1,222,008

: nae 423,168 793,440
52,896 581,856 1,064,320
52,896 317,376 793,440
: ae 1,322,400 1,851,360

: , 687,648 912,032

6,400 528,960 1,024,224

: és 528,960 1,005,024
687,648 852,736

setres 423,168 694,048
52,896 1,692,672 2,274,528

211,584 634,752 899,242

105,792 1,481,088 2,095,744

sa saessiets 317,376 895,840

158,688 360,480

eran: sit : 318,296

290,928 1,646,080

sesedtestanseete Pr las 315,680

79,344 211,584 839,088
9,600 211,584 419,872
6,400 79,344 242,736

158,688 79,344 559,360

52,896 52,896 470,320

22,400 105,792 209,792

39,672 13,224 113,792

125,628 72,732 470,618
13,224 26,448 447,992

46,284 39,672 721,108

52,896 19,836 141,392

52,896 33,060 297,328

85,956 52,896 350,436

Total Protozoa Total Protozoa

Total without with Collotheca Collotheca Total
1913 Suctoria Mastigophora Mastigophora’ egg, attached pelagica Rhizota
Taj «Orestes 20,636 20,636
1/8 Reeser: 1,600 2,000
TDi hat 4,800 5,600 Seececsceeeeees Sotvenecsyereas x
1/15 esupnepnces meee 63,108 1;042,084 3) eee Meastcdesrseene otyeec ee
1/19 Se sdspiancantast 132,440 S865 2,50 sccivesccteee Wee eesee Be tata
1/22 erate aire farce 251,232 352,012 thibecdseeee ae
1/26 eens seauuerevs 899,632 WU 2 S24 aac. cca Be dinpns esses cote
A2OS tires e 391,308 685}8360 0 eda. seee Hepaaacsaosscaae ccoss anes ane
2/92 ee, ee 53,484 82,732 sasesvdoucdeeees SPevacehesyes sbasuss sees
2/5 saveseareonese 103,980 QAO D ne OF seen estreeees Aicucigutesis: ““peesesen teens
2/8 spesutenecestee 85,272 623,032 Fe ee ere a bedgucwebtenet sawcooeent keene
2/12 Sees 284, 104 537,760 dasodeceedenete ane : eine eee
2/15 a ee ar ete 650,752 972:928: x: Saansenas oe cas sive
2/19 Seustiewredeaese 282,456 1,844,016 Sorensen ae saa seas a
2/23 ee eee 412,720 S02) 6169 onsets Sipesbessuucesee a gecbsecs tothe
2/26 Se ee Sarat 484,720 1239\664 0 Sictsscccseee: 5 jrases aeons
o/ I adveveesiweessxe 785,344 ~ 1,279,008 Fees
3/25: Eticventcuss 302,128 SOVOT2 0% oakcs.sscee 5 Rovees tts 35;
3/ 8 eres Posniee 460,816 iyi By OR tetereterecc ncenppannes Sxahtias ese
3/12 Sieaecas cae 1,538,782 1599: OVS Se ae Fa cscichagiss aah :
3/15 absvekantek F 251,488 432,576 SAvraceeeeie
3/19 Rarpseeee ae 895,184 952,880 Sis ciuaieee ae ids arn
Doin e Werecseatrcuess 780,544 S94 336i v P Riow ater Meet

1920] Allen: Plankton of the San Joaquin River 175

TABLE 1—ORGANISMS Per CuBic METER IN PLANKTON OF
SrockToN CHANNEL IN 1913—(Continued)

Total Protozoa Total Protozoa

Total without with Collotheca Collotheca Total

1913 Suctoria Mastigophora Mastigophora egg, attached pelagica Rhizota
3/26 : 384,624 702,048 ees 0153 destassteczeeaas sa ccbeeksteeeeee
3/29 286,032 768,400 OEE Soa LE cay ie ees abo
4/2 452,624 612,912 Bare ‘ Roe cecenseeces idgevesacthatete
4/5 424,672 ASOT Sige tsccicteveess, U0 Sizcesstesteeesy yest

4/9 445,568 459,968

4/13 138,104 150,904

4/16 390,472 SIG AAO fe Seccccscte nthe slew) Green

4/19 340,528 404,624

4/23 442,272 1,662,080 Ae accosveres ees AlassScbeseeesee

4/26 702,048 920,032 Sivsecsssehgeres Bec daccenneettes

4/30 Soak 1,005,776 1,141,216 a ae eaeetas ;

5/ 3 erect 2 993,276 1,284,204

Ly TP) Seceereeseerere : 769,344 822,240

Ly ANE ae ee 907,232 1,277,504

By ASR Rone at oe 1,854,560 1,966,752

5/17 soa enetees 3,345,248 3,927,104

Sy/27 Ie eee : 2,280,928 2,502,112

5/24 peters 2,016,448 PAPASOM SPN. | te Scenes ae § leet eres

5/27 oe Re 2,125,440 21657, 600 9) =..--

5/31 cam eee 2,107,456 3,647,840

6/ 3 ahaa 2,962,176 3,709,120

6/ 7 Se eseoe 3,920,714 4,925,738

6/11 ndescasceevs - 3,074,368 4,185,184

6/16 3,547,172 5,044,260

6/18 2,915,680 4,419,168

6/21 3,887,008 4,587,456

6/25 4,306,576 ONTOS; 908) 9 Lee

6/28 3,544,032 VAMP SOD eedinessere a9 Gorton:

7/3 2,601,504 EZ S A wl eric eee tees reese entero NN Ure secapen eres
7/5 SGUOSD ED C20STOX oh ee Sie eee
OD): ee 1,804,864 ANQDIVAAQIA Vescwstresy | posctseecers) ~ vttemengee
7/12 905,632 7,100,864

7/16 IioleB0S) A LOOAG4

7/19 1,434,592 8,476,160

UPR ~ Wepre 899,232 AVS5 USA civscceceenz

7/26 Beers 2,125,440 10,324,320 ........ eas sees = Se cde
7/30 Beer? 1,535,488 5,779,968 Etec ee Spe Ree Mane A Aes :
8/ 2 eee ree 3,547,232 8,379,968 eres Sciatsia tenia ee eee
8/ 6 oasgaco eee 1,114,016 6,102,240

SVC) Ween 2,277,128 5,190,208

8/13 raed oats 5,666,262 14,152,012 sivdsstks fuwtr< sattentiecaoeese {eee toot
Slr eee ioe 3,398,144 10,178,482 Ventecaaiaesdtes 6,400 6,400
8/20 Sr sae eens 2,284,128 12,757,536 ee nn Rae She eroes-aneves rere F
8/23 : ones 2,987,776 11,880,704 wdeeyvoneks 6,400 6,400
8/27 Acree 1,235,808 9,755,264 ee eee SisedeiawnGts |. Pevatoase eee
8/31 Fee ae. 2,980,176 14,299,920 po ec sheee SN ee pede Les
9/ 2 : 1,430,992 16,634,544 12,800 6,400 19,200
9/ 6 1,705,472 18,529,600 ote ae cneee Tneaaesaeeteas See
9/9 1,226,208 23,872,096 deraesttoriiee ees Sei

9/13 1,248,608 22,883,072 See meats

9/17 LOSOGSS! (22502-2000 oe vs tot ont

9/20 1,328,192 10,902,368 tga venstea Seno roe

9/24 1,484,592 8,899,328 ee 1 peteteucae:

9/27 1,163,712 15,868,800 eros | oc rete

10/ 1 PRG (elay © STO MOO eee eeeerccecrroe eascecccceReeras

10/ 4 1,440,992 8,071,192 sede liccen ees wees ageestass meee :
10/ 8 1,894,496 7,854,208 Seeaineeeers 6,400 6,400
10/11 1,804,864 8,740,640 soca acts Eee near :
10/15 1,335,200 OOD SAA tecesceeeeeee ; 105,792 105,792

University of California Publications in Zoology

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF

Total
Suctoria

Rotaria
neptunia

3,200

SrockTON CHANNEL IN 1913—(Continued)

Total Protozoa Total Protozoa

without

Mastigophora

1,223,008
4,020,096
2,591,914
3,377,436
1,753,750
5,339, 104
1,746,488
5,565,184
2,279,232
1,718,272
424,672
297,232
957,680
478,320
267,488
116,992
471,018
449,192
721,508
143,392
298,128
350,436

Rotaria

rotatoria
112,404
213,420
178,524
. 449,616
720,708
185,136
1,309,176
1,243,056
1,282,728
1,335,624
1,203,384
1,626,552
1,401,744
357,048
674,424
1,057,920
1,745,568
1,639,776
766,992
2,512,560
1,269,504
714,096
793,440
343,824
528,960
79,344
290,928
317,376
132,240
185,136
105,792
79,344
3,200

wit

Mastigophora

7,676,320
9,838,656
7,617,034
10,636,988
9,806,752
10,946,080
8,119,608
19,430,336
9,644,576
7,386,144
6,239,184
2,841,040
4.274.880
3,258,560
2/340,032
1,141,852
1,690,826
1,878,584
1,469,628
1,283,856
1,647,776
1,389,720

Rotifer egg,
winter

Collotheca

egg, attached

Rotifer egg,
unidentified

“79,344
800

1,600

Collotheca
pelagica

Rotifer
unidentified

105,792
6,400
3,200

~ 1,600
1,600

[Vou, 22

Total
Rhizota

Total
Bdelloida

115,604
231,420
178,524
451,616
727,908
193,136

1,375,496

1,329,012

1,293,928

1,361,024

1,284,728

1,864,536

1,428,744
369,848
676,024

1,064,320

1,755,168

1,692,672
768,592

2,681,552

1,275,904
720,496
798,240
343,824
588,256

§2)544
290,928
449,616
135,440
186,736
105,792

80,944

4,800

1920] Allen: Plankton of the San Joaquin River 177

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF
SrockToN CHANNEL IN 1913—(Continued)

Rotaria Rotaria Rotifer egg, Rotifer egg, Rotifer Total

1913 neptunia rotatoria winter unidentified unidentified Bdelloida
AVS OMI eres ntte ce 79,344 es ate a 79,344 158,688
5/ 3 ee 79,344 saree sekdeee : Ls 158,688 238,032
Sa 105,792 Orasveueeeeratte Bee eS 1,600 107,392
5/11 1,600 tase : : Sexi ; 1,600
Sythe eas ircie 6,400 Lota 6,400 6,400 12,800
BYR oe eeerarinee are 370,272 6,400 Ercan 211,584 581,856
§/21 Seg steaee 3,200 5 Jeageaaneneeas : att 264,480 267,680
5/24 Sieaauheaseeeas 25,600 edsttowutaeeeene ea Eta 264,480 290,080
5/27 ste wchies eed 6,400 iravaleetceste soto ee ae Prone aeeeeh eee 6,400
5/31 Rseseadeneaeais OVLOO Se eviecrectansas sdane Sheeeen 6,400 12,800
(S/) hy - eae Si dihee GY4Z00) 9 cise. non Toga eiebeees 3,200 9,600
6/ 7 Bitte ; Aicslaecesestd Se eee SeaA SECIS caceer pec gearCho 6,400 6,400
6/11 Ceyeeronen. sated sped ais Bienen : daceerevs pulscezsaeaeeet 3,200 3,200
6/16 enbheaaeceectors Beas nes : tects ; ecceceiss 12,800 12,800
6/18 ase 19,200 oe , hasissesste ee 3,200 22,400
6/21 : : 19,200 Dpocevedtesten obs é 6,400 25,600
6/25 ea 158,688 seeee 3,200 6,400 165,088
6/28 esi 423,168 fe 3 iosccoaeasestea ezessene ‘ 423,168
“fs 6,400 158,688 , See eheceaes te nes : 165,088
UL Rides aeeeceivens 19,200 core rte ; cise 158,688 177,888
7/9 a : 6,400 wane 5 ween : 3,200 9,600
7/12 Pot eee : 211,584 Aes rie bos é 3,200 214,784
7/16 a . 19,200 ase : ; : 19,200 38,400
7/19 oer en tae. eee eee Sere eho aa 158,688 158,688
7/23 Be denen 317,376 : : : : Pere 317,376
7/26 : 12,800 Prete Nottie 26,500 38,400
7/30 6,400 6,400 Seen nL eopeeecoeer 3,200 16,000
8/ 2 6,400 32,000 19,200 se iucataeeee 3,200 41,600
8/ 6 6,400 32,000 3,200 «dace sah geeee 211,584 249,984
8/ 9 6,400 370,272 DCSE rote ead 9 ee 376,672
8/13 tawcicrasceres 105,792 Dviease —-acehas : 317,376 105,792
8/15 57,600 153,600 Meee ee ee Re vecsn costed: 317,376 528,576
8/20 25,600 237,184 Bhd iramogance en = 158,688 262,784
8/23 12/800 GOOG sie in Bk 6,400 35,200
8/27 32,000 105,792 Macnee = ystceiiis : 158,688 296,480
RUS IMMER eee 8 ence sae fe UES ON eee 105,792 105,792
9/ 2 Bree Bg, ceneenravers : reach etieetbecets | latveewssracenies 3,200 3,200
9/ 6 eer cree 6,400 : : : : 105,792 112,192
9/9 Sere tose 3,200 atnperasteese 3,200 3,200
9/13 Beare 12,800 emer ene ; exc 105,792 118,592
9/20 12,800 211,584 ictanevdecaesace sdevne qusrede 6,400 230,784
9/24 12,800 6,400 Poke : sro Buco anaiapees 19,200
9/27 ee Gebers | UEDRE SCOR ERIOTD We RRO nee Ore : ;
10/ 1 ne ie 52,896 LGuneetsatas Eavtg sve ess aon ae 52,896
10/ 4 25,600 6,400 eae ForeR On IILO ostenate 32,000
10/ 8 6,400 12,800 6,400 agbesexaeventine 211,584 230,784
10/11 6,400 sul ces sey Waureestaeeneest Reise ois mee ees 105,792 112,192
10/15 158,688 65,696 Re itaaetesacirs Scacens seobtien 211,584 435,968
10/18 38,400 19,200 rrabevtlaaie Soir ead a Svcs ; 57,600
10/22 12,800 105,792 La eavermen Phun ee ches 264,480 389,472
10/26 19,200 19,200 6,400 a octnvateeeses 52,896 91,296
10/29 19,200 25,6008 ae: Ras peoosaeeredoaat 211,584 256,384
ity a 76,800 211,584 el nketeeeees Eat aecuuevans 105,792 394,176
TY) 158,688 158,688 bsencee tetra Re secs i ieteceserus 317,376
11/ 8 105,792 105,792 desccceseerth wavspitevereeiss ge kote: 211,584
1/12 105,792 79,344 ar eee ceonceee wee ater de catesssseavees 186,136
11/15 6,400 105,792 6,400 specisatereen a we sictee Steen 112,192
11/19 19,200 317,376 3,200 Bee etcseie 52,896 489,472

11/22 12,800 132,240 6,400 Sener esD 52,896 207,936

178

University of California Publications in Zoology [Von 22

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF
SrockTON CHANNEL IN 1913—(Continued)

Rotaria

neptunia
52,896
16,000
52,896
41,600
19,826
33,060
33,060
52,896
4,800
13,224
52,896

Anuraeopsis
egg, attached

Rotaria Rotifer egg,
rotatoria winter
51,200 9,600
79,344 52,896
TOSS |B kee ae
185,136 1,600
19°836) 0 Vain
800 400
1,600 400
13,224 400
San ie 800
265448 vivessesesses :
39,672 1,600
Anuraeopsis

fissa

~ 264,480
423,168
158,688

Rotifer egg, Rotifer Total
unidentified unidentified Bdelloida
auvatrense Boe 104,096
1,600 96,944
aN peers 132,240
Roraamanecsrtsed 226,736
a a 39,672
33,860
34,660
66,120
4,800
: 39,672
400 92,968

Asplanchna Asplanchnopus Brachionus
brightwellii sp. angularis

132,240
185,136
ee 264,480
ae 978,576
1,428,192
1,057,920
370,272
423,168
179,200
581,856
476,064

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF

Anuraeopsis
egg, attached

~ 41,600

STOCKTON CHANNEL IN 1913—(Continued)

Anuraeopsis
fissa

6,400
6.400

~ 105,792

~ 52,896
6.400
19,200

12,800
105,792
12,800
6,400
108,800
158,688

158,688
132,240
6,400
3,200

Anuraeopsis

sp.

Asplanchna
brightwellii

$3,200
158,688
19,200
44,800
12,800
6,400
3,200
19,200
25,600
44,800

38,400
76,800
25,600
25,600

* 32,000
6,400
12,800

~ 6,400
51,200
3,200

6,400
19,200
6,400
57,600
12,800
105,792
6,400

Asplanchnopus

sp.

179

Brachionus
angularis

158,688

52,896
105,792
370,272
317,376

"52,896

180 University of California Publications in Zoology [Vou, 22

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF
STOCKTON CHANNEL IN 1913—(Continued)

Brachionus Brachionus Brachionus
angularis Brachionus Brachionus Brachionus egg, attached egg, attached

1913 caudatus budapestenensis _calyciflorus capsuliflorus female male

1/5 Recher tyes eee. 6,612 SO ECENT orn JshaWainesites! | eerie

1/8 Resaanaieenernet wie wai 39,672 sp pduaneateees 400 Rip saasbouert

1/12 OeatrrieeaiN 2 9,600 10,000 : Berita 2,400

1/15 ivieatecesntik deck oe 13,224 ; Passat 1,200

1/19 pomsarcescec Urs eetvoateaeoes 13,224 Sere ae 800

1/22 Vase awepe Rae S00! Wee. 4,800

1/26 raded cutest 19:836% ~ “pxiccincnets 19,836

1/29 59,508 ei eaesend 1,600

2/ 2 33,060 FetppacensCerask 33,060

2/5 52,896 srepescsitersees 85,956

2/8 171,912 Diets Secdsiepavs 79,344

2/12 224,808 aeneucntetasese 224,808

2/15 Scere rer 9,600 ee eres

2/19 Resevttespseres akceearssaeeceee 66,120 Upasveueieanacy 39,672

2/23 seusshceaswanere aeoesdszeussts 211,584 Roeeccsscehveah 304,152

2/26 Faedeaecctcuses eeseeasivoeepacs S10) ore aearbses 528,960

3/1 ose a Feet 317,376 Deas 290,928

a] Nave 2c Meee ieee FeccuaetCctuaten e295 ‘9D 2. ue aeciceatcatae 1,375,296

3/ 8 sstasaviseen ‘ satoancee cates. 1,110,816 sade havsgeeee 714,096

3/12 sanenktaeens 5 aecthannscOipewy 3,914,304 Spisvacs copaeews 608,304

3/15 Treavenccewuasee Sosczasceseeee 132,240 5 ae 92,800

3/19 por norhavesereee Tesh ovo cet eee 264,480 neiboee saaeentes 105,792

3/23 Rear Voradisbecagtere » 449,616 Pia ieetee 132,240

3/26 eae en ere 343,824 aesepuapeaes 317,376

3/29 ocdeodaeahies 264,480 1,600 290,928

4/2 714,096 ersificsweee 185,136

4/5 scssabienatce SO) | veces wir 3,200

AV OY mth tere. Seocgssecpents 1G’ OOO essere She aes

CUS viper Bere tree Piers resect 19,200 Pececst tents: 12,800

Bil Gige | Meeiecncaties ; 79,344 F 52,896

AS OMe tee nesters 38,400 9,600

PRIS = Are east tO AGRE en rcetreeees 12,800

A 20a gia, Rory. pe reastets 57,600 aN cores 9,600
4/30 Barco ee Pivcendettaceety 25,600 css seats 61,600
5/ 3 12,800 a eetiespepesaps LOS SO 2S i eeeseereerere 79,344
Dake aeiestets Rlovatiny a Te Sees 185,136 6,400 502,512

Beet eet oe, eee TOME Grosser ants 238,032
Gai ah eh be a ees 140,800 12,800 370,272
BY Pa ete te ere 102,400 6,400 423,168
5/21 121800) ene eee 44,800 ....... 211,584
5/24 1D S00ME eee 6,400 317,376
5/27 S500 me ene rears 423,168
5/31 PAU takey Rare ee AMEE ed Micon geek 211,584
6/3 BSUS Te atta ceo) Meee ne oe ee 899,232
6/7 952,128 .... bpet an Mika ae sae ante 476,064
6/11 702720 hee a) OB ets See 6,400 288,000
6/16 S173 me ee anne ee 952,128
6/18 S09;230 umm Ss POL Cee ee nee 370,272
G/2ia ULOSIG = yc eee Os ee 2 ee 793,440
6/25 2,591,904 ............... PEAS 6,400 846,336
6/7 2Steh 1 O69 504ee oy ee en ps ene 6,400 528,960
7/3 GS7G4se) ne 5h Raoul te 158,688
7/5 AFC 060.» eer nes POET IIR. See ct 158,688
HE GN GR YG = i 3.200 ..... ne 687,648
leet S75 O06 eee Een) etna 528,960
7/16 70510 Rene re oa eee 846,336
7/19 HOS AAD) = Seceannnes Fee il é 476,064
7/23 S17 3760. een ee se 6,400 158,688

7/26 1,481,088 Berra Bi400) Piers cores 370,272

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF

Brachionus
angularis
caudatus

423,168
211,584
105,792
105,792

1,269,504

1,428,192

1,692,672

899,232
952,128
317,376
476,064
476,064
2,433,216
2,062,944
687,648
19,200
264/480
740,544
581,856
581,856
793,440
423,168
264,480
158,688

Brachionus
egg, free
female
13,224
33,060
6,400
26,448
13,224
400
19,836
13,224
92,568

SrocKTON CHANNEL IN 1913—(Continued)

Brachionus
budapestenensis

19,200
6,400

- 52,896
~~ 6,400
"6,400

Brachionus
egg, free
male

Brachionus
calyciflorus

~ 6,400
~~ 12,800

6,400
~ 6,400

6,400

~ 6,400

3,200
6,400
3,200
3,200
9,600

800

Brachionus
male

Brachionus
capsuliflorus

6,400

Brachionus
plicatilis

1,600
2,000
5,200
13,224
26,448
4,800
26,448
52,896
92,568
99,180

Brachionus
egg, attached
female

12,800
2,644,480
3,200
158,688
317,376
687,648
952,128
740,544
476,064
105,792
158,688
317,376
1,269,504
476,064
370,272
6,400
105,792
1,005,024
370,272
423,168
634,752
158,688
158,688
52,896
211,584

~~ 6,400

Brachionus
urceus
6,612
400
800
400
1,600
400,
17,600
59,508
52,896

181

Brachionus
egg, attached
male

~ 105,792

~ 105,792
19,200

"52,896
19,200
211,584

Brachionus
with —
endoparasites

182 University of California Publications in Zoology [Vot. 22

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
StTockTON CHANNEL IN 1913—(Continued)

Brachionus Brachionus Brachionus

egg, free egg, free Brachionus Brachionus Brachionus with
1913 female male male plicatilis urceus endoparasites
2/8 119,016 die cboevseceests weaonatnnaes fact 79,344 52,896
2/12 39,672 ee raw re hee : 132,240 105,792
2/15 Oe ee ees 1,600 3,200
2/19 92,568 ee a reer 3,200
2/23 171,912 800 Pearceuseresctes 17,600
2/26 105,792 S100). = Ra eee ee 16,000
3/1 SOISUR MNNN te ele weet 25,600
3/5 211,584 79,344 132,240
3/8 52,896 ceeseey E Byarteasn seins 12,800
3/12 476,064 1,600 1,600 38,400
3/15 ee ; 6 : 6,400 19,200
3/19 158,688 1,600 Mersiccireystess 12,800
3/23 185,136 oe ” ah cce . 6400.) \ ied eee ee
3/26 264,480 __..... te one nee 22,400
3/29 211,584 am Sears 25,600 Sepesudcaeemeey
4/2 EOL ee eee te eee ts 9.G00. hace. aee we
4/5 52,896 bss ctustesteuane vaeaxes cattbae ts 19'200. cies nd rresepcicyccc
4/9 CGOUP AN. Rit) up eoaee nT ere 3200" ae
4/13 Seva aretetare sreacoaretcnte eect SIZQO | Svceacseeteeete ene ee eee
eal ies RSC, Meese tree tamer Aaa ee 2 a : sccsobicedcaat> UMUy aetna eee
4/19 DS GOO ee eS OD eas ooec casey ibe Gusseetoetee ot ee ee
4/23 3,200
4/26 1,600
4/30 1,600
5/ 3 Bide
Syl U Be ere
5/11 423,168
5/14 423,168
5/17 1,005,024
§/21 211,584
§/24 211,584
5/27 211,584
5/31 317,376
6/3 158,688 ate oy eos 899 2¢ cea ceeee
6/ 7 211,584 sapriemiasaes 3,200 oS : 740,544 een Cie
6/11 317,376 nacgeeanaats Boca nee: wens res 505,600 beet site
6/16 370,272 serene Jt ees eens 423,168 eS cA
6/18 317,376 Miterst eon ce Sedosceneee a 687,648 aa ¥
6/21 317,376 Reeeparersssness SePiasas pase 3,200 899,232 seeee Me
6/25 581,856 oe : aes Fee 581,856 528,960
6/28 687,648 —...... Petar as iehs 6,400 128,000 rr Pt
pas 264,480 aos Secs - Be 51,200
7/5 OOS O24 Ines a ete eae 6,400 44.800
7/9 899,232 Bcpsene dctvsdancatnece RUrahecs 44,800 aioe ots
7/12 1,005,024 Retest . eee ie ; 528,960 sincoaveve hones
7/16 370,272 Bacevece : aoe on : 528,960 Suansoateantees
7/19 264,480 een nevtaaeee scores : : 370,272
7/23 740,544 B: ae — whe: e 6,400
7/26 476,064 Sacre : : 5 : 423,168 er os
7/30 423,168 sae fee 3 : cae 105,792 12,800
8/ 2 423,168 secee Sets ; ; evstecereredend 370,272 3,200
8/ 6 634,752 a : ae : 264,480 6,400
8/ 9 1,163,712 Storeustceeets notes 6,400 793,440 Ae
VAY TIGiMOSIG) aniees oy 105,792 ERR: 799.440 ° 2 ae
8/15 BODE Oo acne aie Wie ot |e ae oie 264,480
8/20 2,486,112 S jaatacaeels Se aati Drs ieicccanesia 476,064
8/23 634,752 ee : Witte - ayceaereee 581,856
8/27 1,005,024 seasatcusyeaPers pascetbuawesce = Mckee rannes 370,272

8/31 687,648 ME ico Sree enecere Si sazatenseseees 105,792

1920]

Allen: Plankton of the San Joaquin River

TABLE 1.—OrGANISMS PER CuBIC METER IN PLANKTON OF

Brachionus
egg, free
female
634,752
846,336
793,440
1,057,920
370,272
687,648
476,064
370,272
370,272
952,128
793,440
952,128
634,752
952,128
528,960
264,480
317,376
105,792
105,792
158,688
52,896
238,032
370,272
132,240
449,616
449,616
158,688
46,284
119,016
33,060
66,120
26,448
72,732
105,792

Diurella
egg, free

SrockToN CHANNEL IN 1913—(Continued)

Brachionus
egg, free
male

Diurella
tenuior

Brachionus
male

Epiphanes
clavulata

Brachionus
plicatilis

Filinia
brachiata

Brachionus
urceus
96,000
105,792
211,584
211,584
12,800
19,200
121,600
264,480
158,688
105,792
158,688
105,792
211,584
44,800
32,000
6,400
12,800

Filinia
egg, attached
female

400,

92,568
26,448
158,688
581,856
555,408
105,792
1,481,088
423,168
1,190,160

183

Brachionus
with
endoparasites

Filinia
egg, attached
male

“2,400

277,704

79.344
132,240
502/512
238,032
105,792

184 University of California Publications in Zoology [ Vor, 22

TABLE 1—ORGANISMS PER CUBIC METER IN PLANKTON OF
SrocKTON CHANNEL IN 1913—(Continued)

Filinia ‘ Filinia
Diurella Diurella Epiphanes Filinia egg, attached egg, attached
1913 egg, free tenuior clavulata brachiata emale male
OL)» oe cerecareceresss 132240" eoeenses
SL Obie ay eee crsccsceee 185,136 158,688
3/23 L376)" wercnureees
3/26 132,240 RPA ec
3/29 476,064 52,896
BMD | einer rateeks 132,240 Behe ci:
4/5 i D2;896; Pees
4/9 1,600 sinvacs todas
4/13 LSS eae.
4/16 AO B44 Tee renee
4/19 1.6000) yew ee
4/23 158,688 creer
4/26 317,376 132,240
SON cata ese SOE DEM sastcssoachpeteoe'n | oo Wbechittenceceuate . WBMCR: eure utee nalenalits eet epee ; SelvieseMiete
5/ 3 158,688 211,584
VE i 502,512 185,136
5/11 158,688 105,79
5/14 211584 las cs
5/17 105,792
PALE aetern cee meets castrate | PIO ce ee ,) "VAR
Ly PX Eee Tei aee i eee Sducttee) |) ence eee
5/27 105,792 3;200) sc aeueeee
§/31 105,792 sieniete, mess ee
G/ESS) na etre 10557927 7 eee
Ohne. ECAR CR aaa Sere OOOO RW ee
VO) eee ene Meer err ey mmo enret msrere eoce. | pense chacosurc
G/TG ~~ B3ZOO! eck 9 weiscccceteven) 7 Wecacenaedeenscbet Uy cepeseecee oe enc nIME enee nee
6/18 6400: 22 ee
G/2D ieee cacdccapeesane, Ay) p/asiesssonncveien’ o pylvecweras res el Pees tary cake oe
6/25 3,200" 9 earaetene
6/28 211,584 317,376
7/3 3:200)— feito
7/5 158688 aes
7/9 33200)" cheeses
WD ©. woke Ve, | AR ee eee
7/16
7/19
7/23
7/26
7/30
8/ 2
8/ 6
8/9
8/13
8/15
8/20
8/23
8/27
8/31
9/ 2
9/ 6
9/9
9/13
9/17
9/20
9/24
9/27
10/ 1
10/ 4

1920] Allen: Plankton of the San Joaquin River 185
TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
StTocKkTON CHANNEL IN 1913—(Continued)
Filinia Filinia
Diurella Diurella Epiphanes Filinia egg, attached egg, attached
1913 egg, free tenuior clavulata brachiata female male
10/11 ndkeaeeate
10/15 52,896 105,792
10/18 52,896 nee
TIDE | PRE er tAic) aReRR sn ai a aie i> a a a De
10/26
10/29
n/a
GMO wmumrer seme |) sts eee my ee
11/ 8
11/12
11/15 Rea Pectee Fe oarrerced Bs oc
LTA) Eoin | EEE etn beeen 105,792 1,600 wedeeentere
LEY) 22 es eres Oe erg Oe | Urs, 105,792 79,344
11/26 52,896 1,600 wee
11/30 1,600 oe
127-3 oe
12/ 6
12/10
12/14
12/17
WPAD:. _. ganaeesetecetin, "uses tererondh POPPERS As TIMP einen nents vi apie Maine emi FST eee
12/24
212 a ee ee tte Be eee MOR IR
2) (3) ee TE eC EE teeta A eautet. | cudiarainy
Filinia Filinia Keratella Keratella Keratella Keratella
1913 egg, free longiseta cochlearis egg, attached egg, free male
1/5 PED in eee es | ees TPXTBD- —cooortnectenats
/8 20,800 nenieise 400 79,344
1/12 5,600 400 6,000 25,200
1/15 26,448 13,224 26,448 99,180
1/19 2,400 400 26,448 46,284
1/22 1,600 33,060 19,836 39,672
W/Z Oa ese ‘SOO Meee ‘ ; 72,732 138,852
1/29 46,284 800 112,404 125,628
22 4,800 13,224 33,060, 171,912
2/9 13,600 800 39,672 145,464
2/8 66,120 800 171,912 SASS 2a creer
2/12 304,152 52,896 436,392 899,232
2/15 19,200 9,600 3,200 800
2/19 seevesewe 383,496 14,400 6,400 132,240
2/23 105,792 2,062,944 39,672 52,896 198,360
2/26 132,240 1,401,744 79,344 79,344 449,616
3/1 238,032 555,408 79,344 9,600 :
3/ 5 1,904,256 3,702,720 158,688 1,600 79,344
3/ 8 793,440 6,083,040 105,792 158,688 1,600
3/12 899,232 5,025,120 105,792 1,600
3/15 290,928 1,110,816 28,800 1,600 1,600
3/19 449,616 1,586,880 343,824 290,928 1,600
3/23 211,584 978,576 211,584 211,584 79,344
3/26 52,896 608,304 238,032 423,168 396,720
3/29 52,896 608,304 158,688 555,408 740,544
4/ 2 aes i 238,032 370,272 132,240 2,089,392
4/5 238,032 132,240 1,454,640 872,784
4/9 132,240 238,032 608,804 2,115,840
4/13 476,064 48,000 502,512 2,115,840
4/16 185,136 6,400 264,480 2,062,944
4/19 264,480 211,584 925,680 1,295,952
4/23 290,928 290,928 423,168 1,005,024

pS

PR e Rory wien s) iu)

WNW
om

6/
6
6,
7
q,
@,
7)
q
7
7
7
7
8
8,

Seo RN ae

IDO ONO

University of California Publications in Zoology

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF

Filinia
egg, free
608,304
899,232
819,888
819,888
502,512
105,792
211,584
581,856
370,272

~ 105,792

3,200
158,688

3,200
105,792
158,688
370,272
476,064
370,272

~ 105,792

105,792
211,584

158,688

3,200
264,480
423,168
370,272
476,064
158,688
158,688
264,480
105,792

3,200

3,200

3,200

"52,896

52,896
52,896

105,792

211,584

52,896
52,896

158,688

211,584

~ 105,792

132,240

SrocKTON CHANNEL IN 1913—(Continued)

Filinia
longiseta

581,856
264,480
370,272
1,930,704
925,128
1,639,776
1,057,920
158,688
6,400
158,688
25,600
211,584
51,200
6,400
38,400
51,200
211,584
423,168
1,110,816
264,480
1,375,296
12,800
105,792
25,600
6,400

Keratella
cochlearis

211,584

~ 1,600
105,792
52,896

3,200
6,400
3,200
19,200
158,688
6,400
211,584
317,376
264,480
793,440
211,584
423,168
12,800
32,000

52,896
158,688
264,480

28,960
423,168
105,792
211,584

89,600
132,240

51,200

52,896

Keratella
egg, attached
423,168
476,064
502,512
1,005,024
819,888
370,272
3,200
158,688

105,792
3,200
634,752
105,792
105,792
158,688
476,064
211,584
1,533,984
1,957,152
317,376
211,584
3,200
3,200
105,792
211,584
211,584
264,480
105,792
158,688
3,200
105,792
105,792
3,200

317,376
3,200
3,200

12.800

105,792
3,200

423,168
3,200

12,800
52,896

370,272

634,752

793,440

1,798,464
1,216,608
1,216,608

423,168

634,752

423,168

476,064
6,400
6,400

25,600
52,896
12,800
28,800

Keratella
egg, free
1,930,704
1,533,984
1,243,056
2,036,496
793,440
476,064
317,376
476,064
476,064
211,584
476,064
,322,400
370,272

3,200
264,480
528,960

1,586,880
1,533,984
1,481,088
3,200
476,064
211,584
687,648

_

~ 105,792
3,200
105,792

~ 264,480
3,200

370,272
158,688
158,688
105,792

79,344
581,856
714,096

[ Von. 22

Keratella
male

1920]

1913
11/22
11/26
11/30
12/ 3
12/ 6
12/10
12/14
12/17
12/20
12/24
12/27
12/31

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF

Filinia
egg, free

185,136

“105,792
52,896

Keratella
quadrata

26,448
92,568
79,344
152,076
$5,956
39,672
231,420
323,928
198,360
125,628
423,168
1,124,040
11,200
79,344
251,256
132,240
16,000
41,600
925,680
317,376
343,824
952,128
740,544
1,084,368
2,142,288
3,385,344
4,205,232
3,041,520
925,680
1,719,120
4,205,232
2,195,184
2,459,664
2,010,048
1,613,328
3,067,968
5,104,464
2,909,280
1,005,024
1,322,400
317,376
740,544
$46,336
1,533,984

Stockton CHANNEL IN 1913—(Continued)

Filinia
longiseta

Keratella

cochlearis
48,000
51,200
52,896
57,600
3,200
1,600
800
1,600

Notholea
striata

Keratella
egg, attached

22,400
28,800
19,200
52,896
52,896

6,400
72,732

4,000
46,284
13,224
26,448
66,120

Notommata
aurita

~ 400

6,400

Keratella
egg, free

423,168
79,344
105,792
52,896
52,896

46,284

1,600
19,836
19,836
39,672
79,344

Polyarthra
trigla

1,200
39,672
800

800
19,836
66,120
1,600
19,836
105,792
39,672
4,800
14,400
105,792
28,800
79,344
370,272
581,856
158,688
238,032
132,240
25,600
79,344
105,792
158,688
396,720
1,110,816
1,560,432
766,992
1,772,016
370,272
2,644,800
2,062,944
1,216,608
3,147,312
2'724.144
528,960
264,480
57,600
38,400
19,200
19,200
105,792

187

Keratella
male

Polyarthra trigla
egg, attached
female

“3,200

52,896
1,600

ores

PWO NO

See
wm OS

ODOOWMHHHHHHHIINIIIIIIIOAS
=z)

10/15

10/22
10/26
10/29
11/ 1
1/5
11/8
11/12
11/15
11/19
11/22
11/26
11/30
12/ 3
/ 6
10
14
/17
/20
/24

VNUNYNNNWLY

a

University of California Publications in Zoology

TABLE 1.—OrRGANISMS PER CuBIC METER IN PLANKTON OF

Keratella
quadrata

846,336
528,960
317,376
740,544
1,798,464
6,030,144
7,035,168
1,798,464
1,163,712
264,480
1,322,400
952,128
846,336
1,692,672
2,062,944
2,010,048
1,110,816
687,648
740,544
$99,232
423,168
1,163,712
1,904,256
528,960
581,856
158,688
317,376
899,232
1,957,152
1,005,024
89,600
846,336
1,322,400
1,533,984
2,062,944
5,395,392
4,866,432
3,914,304
2,010,048
2,697,696
952,128
1,269,504
581,856
64,000
19,200

12,800
25,600
12,800
25,600
38,400
79,344
35,200
- 33,060
132,240
33,060
92,568
46,284
85,956
125,628

SrocKTON CHANNEL IN 1913—(Continued)

Lecane
luna

~~ 6,400

400

Notholea
striata

Notommata
aurita

Polyarthra
trigla
6,400
19,200
51,200
317,376
476,064
1,005,024
687,648
19,200
158,688
899,232
1,692,672
687,648
158,688
134,400
634,752
952,128
793,440
687,648
2,327,424
952,128
1,057,920
1,904,256
1,428,192
952,128
581,856
952,128
264,480
846,336
1,057,920
264,480
899,232
581,856
740,544
476,064
581,856
634,752
634,752
634,752
740,544
423,168
44,800
32,000
158,688

"52,896

6,400
476,064
158,688
185,136
528,960
264,480
449,616

46,284
495,900
66,120
66,120
5,600
46,284
132,240

[ Vou. 22

Polyarthra trigla
egg, attached
female

3,200
3/200

3,200

12,800
3,200

~ 105,792
105,792

"52,896
52.896

"52,896
105,792

19,200
264,480
19,200
108,800
132,240
28,800
52,896
1,600
66,120
13,224
13,224

800
1,600

Allen: Plankton of the San Joaquin River

TABLE 1—ORGANISMS PER Cubic METER IN PLANKTON OF

SrockToN CHANNEL IN 1913—(Continued)

Polyarthra
trigla egg, Synchaeta
attached male sp.

317,376
2,644,800
1,745,568

Trichocerca
capucina

Trichocerca
iernis

“12,800

6,400

6,400
6,400

6,400

19,200

211,584

317,376

6,400

6,400

12,800
19,200
19,200

Total
Ploima
199,960
268,644
142,544
419,944
221,984
148,640
530,960
$27,464
696,848
807,840

1,667,024
3,783,664
96,848
990,528
4,386,320
4,058,896
1,924,960
11,674,672
11,317,848
13,336,096
2,468,480
4,663,600
3,587,984
4,062,448
5,717,472

5,263,056
9,316,752
5,025,776
9,573,136
8,009,552
6,757,440
13,932,448
13,163,008
8,664,960
5,911,168
5,143,968
2,556,128
2,786,620
3,194,464
7,483,936
4,018,208
2,556,672
3,464,960
4,797,336
7,916,704
18,537,504
17,647,680
4,125,504
7,111,968
5,127,720

e

09 > 109 08 He OP

189

Total Ploima
without eggs
114,004
155,440
102,544
258,268
130,028
83,932
301,540
567,996
403,120
364/836
900,032
1,985,200
60,000
560,960
2,692,848
2,107,392
1,082,672
5,722,272
8,856,584
9,577,280
1,898,112
3,011,552
2,618,720
2'390,672
2'525,552
4,898,432
5,398,400
4,726,944
3,075,776
2,801,792
6,526,912
3,211,312
6,017,904
4,508,062
3,504,336
8,775,088
9/936,352
6,701,408
3,845,024
3,504,192
1,180,832
1,786,492
2,186,240
4,359,872
2,854,496
1,842,304
1,466,400
3,085,064
4,835,936
13,717,568
12,358,080
3,219,872
4,731,648
2)843,592
5,979,752
3,026,176
2,219,936
2,208,448
4,649,952
3,552,136
2,683,704

190 University of California Publications in Zoology [ Vou. 22

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrocktoON CHANNEL IN 1913—(Continued)

Polyarthra

trigla egg, Synchaeta Trichocerca Trichocerca Total Total Ploima

attached male sp. capucina lernis Ploima without eggs

aia : Wier wicarekuede 158,688 2,551,808 1,907,456

12,800 SEN stators 105,792 6,029, 196 3,966,252

aeaghout ai ie Seaarvancenen 19,200 6,082,848 4,116,096

Racuieere sedevits , Met tust ices ke 105,792 5,332,704 3,869,152

wees ee ia se ey, ener 9,205,408 5,287,904

6,400 sais Braye 3,200 6,716,096 4,864,736

Sse ; rate bt nd ie Peer eecta che 4,491,296 2,835,520

6,400 2,686,400 1,625,280

arnt 2,630,112 1,714,880

6400 Site 2,551,808 1,170,112

cs 6,597,504 4,403,168

7,419,744 5,353,600

2,736,096 1,992,352

ae 1,786,976 1,080,128

ives 2,812,200 2,065,256

ke ne 5,342,496 3,491,136

52,896 4,699,648 3,218,560

eee : wes 792 5,744,868 3,470,340

6,400 6,400 10,444,416 7,105,568

10/11 porecce a : aapasetovereeese 12,800 8,548,256 6,115,040

10/15 , oe 19,200 Siteesxteccoseas 52,896 7,588,032 5,347,200

10/18 ceeteees 158,688 POE mento coaecenno 4,956,032 3,474,944

10/22 : 5 105,792 Teiceebaschees ene EEeeceec oncecete 5,980,266 3,963,518

10/26 Ba As 3 6,400 ee ec eee tate 2,436,224 1,589,888

10/29 FS nee 44,800 ea eer enene 52,896 3,209,776 2,086,160

1, 1 ; Seeanectp ' Meer tie eee MRO rerob get 1,460,192 1,024,224

11/ 5 , isndewees a ey Pm eric 9. tho brceos 400,576 288,384

Ue Si execs 6,400 352,384 168,096

11/12 seesvasvact ets 105,792 451,968 247,632

WAV asters iesks 105,792 1,018,186 272,888

11/19 a noe 52,896 2,242,896 802,848

11/22 BF eS 132,240 1,972,960 714,752

11/26 28,800 12,800 955,600 496,672

11/30 6,400 79,344 1,618,336 783,296

12/3 ; 79,344 1,121,872 475,168

12/ 6 52,896 853,088 535,712

12/10 33,060 171,088 114,804

12/14 92,568 1,048,696 723,508

12/17 39,672 192,736 140,852

12/20 79,344 384,696 239,232

12/24 39,672 155,864 94,756

12/27 SBiOGO) © welcceccasue detessceseees 306,952 167,300

12/31 AD BEE: | Socrsvcpeces SS Wet eae tence 592,868 340,012

Total Bosmina Bosmina Sida Total Canthocamptus
1913 Rotifera longirostris sp. sp. Cladocera sp.

1/5 315,564
1/°8 500,064
1/12 321,068
1/15 871,560
1/19 949,892
1/22 341,776

1/26 1,906,456
1/29 2,156,476
2/2 1,990,776
2/5 2,168,864
2/8 2,951,752
2/12 5,648,200
2/15 ‘1,525,692
2/19 1,360,476
2/23 5,062,344

1920] Allen: Plankton of the San Joaquin River 191

TABLE 1—ORGANISMS PER CUBIC METER IN PLANKTON OF
SrockTon CHANNEL IN 1913—(Continued)

Total Bosmina Bosmina Sida Total Canthocamptus
1913 Rotifera longirostris sp. sp. Cladocera sp.
2/26 5,123,216 seeeaeca
S/i, 3/680)028: 1...

3/5 18,367,344
3/ 8 12,086,440

BID, IG OUEGES, _....aaee a eet ee ee
ERMC URMEEE GctS Acusniscres 3,200
SV OPRMD SR EOUR yh) cio eee Sac re rts 0 me Oh A Bete
3/23 4,386,224 _.... a. ean aie a A: 3,200
3/26 4,406,272 .. Sf en oe ie a

3/59). AGES 72s et ere

ENE ORAGVIEY TIED) MUMDERIR © as ll NCR cose mI rete a ROMO ew EE See
UE EMOSHUISOL0) ccna. an «REE Sh eae ee 3,200
VOUS OG 21502 cee she ae e meee ee
VAR GEG CBD Ae ae ene ou

4/16 5,449,792

4/19 9,422,544

4/23 5,106,720

RVD CIMO STOSGH NR RN | Ssuntaens cates

VBE SUGR O40 heat” caceeentves aioe:

B/S OOD a5

5/7 14,039,840

5/11 13,164,608 -

5/14 8,677,760

ail; Goes - : 3200 .... 3,200
Bot) 5,Ale4s =... Sak ple a Roald te
EY DAME D2SAG 208) cake 6,400... 6,400
5/27 2,793,020 ae ee Rc

6/31 3,207,264

6/3 7.493.536. te es, PVA GA00n 9) G:400
6/7 4024608 . 6,400 GAD, wees

6/11 2,559,872 st : Rebate se iors 6,400 6,400
6/16 3,477,760 : Milenyo Barer sebenten!
6/18 4,819,736

6/21 7,942,304 . Pilg Ta ane 6,400 6,400

6/25 18,702,592 cs bee aris 6,400 6,400

6/28 18,070,648 reece ck Me. a eo ane
OOOO, Lees lees sates ite

TRS CU OSORSO. kee eteeates 6,400 6,400

Tk) WeSIBWBPI) cee eh es ET oar

Ti OP) eee 6,400 6,400

7/16 4,386,976 . ee

7M (3548786... es 12,800 12,800

SS TES OSIM ee a . wees

HS ROMO) OS catcewoce secmeonae 6,400 GLUON peeceenn cece
7/30 4,271,784 GAO wan renal cee 600s
8/2 3,680,632 6,400. 6,400 12,800

URGED SOI OOM un | eee ae ee ee

RYROMM EG A0S:S68), ciuacsees |. ones 6,400 6,400

Sys) 6188640) use cell v eat CE IS

VSMCS COTOSO ms Wee ey pecan i ae

8/20 9,467,192 STOOOM A, of cee ; BAU) ceoves
SOR) AGIOS - cette te 19,200 19,200

Bie | CMaeMe Velecae cree | Meier 6,400 6,400

Sal Drees i ain ut 6,400 6,400

OD DARN reeks © : 25,600 25,600

9/6 2,644,000 ..... yl ARES ee $3

9/9 6,600,704 G00 ee 6,400 12,800

By TAGRISSERIS ae aa ny arr Paes

9/17 2,736,096 G00 men oe 12,800 19,200

9/20 2,017,760 Eee : ceastanseteetes Me : sacciseeapetess
9/24 2,831,400 GA00ID | eecetece: 12,800 19,200

1913

9/27
10/ 1
10/ 4
10/ 8
10/11
10/15
10/18
10/22
10/26
10/29
11/ 1
11/5
11/ 8
11/12
11/15
11/19
11/22
11/26

Fe He He CO OU WI BW BW ROW NNN NNN NNR Ee

University of California Publications in Zoology

TABLE 1.—ORGANISMS PER CUBIC METER IN PLANKTON OF

Total
Rotifera

5,342,496
4,752,544
5,776,868

10,681,600
8,660,448
8,129,792
5,013,632
6,382,538
2,527,520
3,466,160
1,854,368

717,952
563,968
641,304
1,130,328
2,732,368
2,180,896
1,059,696
1,715,280
1,254,112
1,079,824
210,760
1,082,556
227/396
450,816
160,664
346,624
685,836

Cyclops
sp.

6,612
800
2,400
2,000

1,600
1,600
2,400
1,600
1,600
1,600

1,600

~ 3,200
3/200

6,400
3,200
9,600
19,200
9,600
3,200
12,800
12,800
9,600

Bosmina Bosmina Sida
longirostris sp. sp.
sete ee Jusbersoeets 12,800
19,200 an 105,792
6,400 6,400
12,800
~~ 6,400
6,400
~~ 3,200
b: caaenstes ae 3300
800
Diaptomus Nauplius Total
sp. sp. Copepoda
aes cette 800 7,412
1,600 1,600
' 2,400 3,200
ie. ienies 1,200 3,600
RS Pre 2 2/000
[eee = eee 1,600
Ror 5 800 2,400
2,400 4,800
800 2,400
2,400 4,000
1,600 3,200
1,600
3,200
3,200
6,400 12,800
12,800 16,000
12,800 25,600
16,000 35,200
9,600
3,200 9,600 16,000
9,600 32,000 57,600
1,600 105,792 120,192
12,800 105,792 128,192

SrTocKTON CHANNEL IN 1913—(Continued)

Total
Cladocera

12,800

Total
Entomostraca
7,412
1,600

16,000
16,000
25,600
35,200
9,600
16,000
57,600
120,192
128,192

[ Vou. 22

Canthocamptus
sp.

Glochidia

1920]

10/15
10/18
10/22
10/26
10/29
11/1
11/5
11/8
11/12

Allen: Plankton of the San Joaquin River

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF

Cyclops
sp.

6,400
38,400
22,400
41,600
38,400
80,000
73,600
51,200
57,600
211,584
57,600
249,600
192,000
460,800
317,376
147,200
264,480
115,200
179,200
76,800
317,376
264,480
179,200
268,800
370,272
740,544
454,400
687,648
264,480
264,480
317,376
581,856
264,480
317,376
1,005,024
476,064
740,544
476,064
634,752
317,376
793,440
264,480
581,856
476,064
370,272
370,272
224,000
317,376
211,584
211,584
134,400
158,688
121,600
64,000
38,400
158,688
76,800

Stockton CHANNEL IN 1913—(Continued)

Diaptomus
sp.
12,800
52,896

6,400
22,400
44,800

6,400

Nauplius
sp.
25,600
79,344
132,240
185,136
79,344
132,240
185,136
423,168
1,005,024
264,480
634,752
1,163,712
952,128
899,232
899,232
872,784
1,375,296
211,584
317,376
846,336
528,960
476,064
423,168
1,057,920
1,163,712
$46,336
793,440
740,544
1,110,816
687,648
740,544
1,322,400
1,269,504
1,005,024
1,692,672
1,110,816
846,336
846,336
1,216,608
793,440
1,586,880
1,269,504
1,322,400
1,005,024
1,110,816
370,272
952,128
687,648
264,480
211,584
528,960
105,792
264,480
158,688
105,792
105,792
158,688
211,584
6,400
12,800
19,200

Total

Copepoda
44,800
170,640
161,040
249,136
162,544
218,640
258,736
474,368
1,062,624
475,964
692,352
1,413,312
1,144,128
1,360,032
1.216.608
1,019,984
1,639,776
326,784
496,576
923,136
846,436
740,544
602,368
1,326,720
1,533,984
1,586,880
1,247,840
1,428,192
1,375,296
952,128
1,057,920
1,904,256
1,533,984
1,348,000
2,697,696
1,586,880
1,586,880
1,322,400
1,851,360
1,110,816
2,380,320
1,533,984
1,904,256
1,481,088
1,481,088
740,544
1,176,128
1,005,024
476,064
423,168
663,360
264,480
386,080
222,688
144,192
264,480
235,488
211,584
6,400
12,800
22,400

Total
Entomostraca

44,800
170,640
161,040
249,136
162,544
218,640
258,736
474,368
1,062,624
479,164
692,352
1,419,712
1,144,128
1,360,032
1,223,008
1,026,384
1,646,176
326,784
496,576
929,536
852,836
740,544
602,368
1,333,120
1,533,984
1,593,280
1,247,840
1,440,992
1,375,296
958,528
1,064,320
1,917,056
1,533,984
1,354,400
2,697,696
1,586,880
1,590,080
1,341,600
1,857,760
1,117,216
2,405,920
1,533,984
1,917,056
1,481,088
1,500,288
740,544
1,195,328
017,824
601,056
435,968
676,160
264,480
386,080
229,088
150,592
264,480
235,488
211,584
6,400
12,800
22,400

193

Glochidia

194 University of California Publications in Zoology [Vor 22

TABLE 1.—ORGANISMS PER CuBIC METER IN PLANKTON OF
SrockTON CHANNEL IN 1913—(Continued)

Cyclops Diaptomus Nauplius Total Total
1913 sp. sp. sp. Copepoda Entomostraca Glochidia
11/15 12,800 Peer aee 211,584 224,384 224,384
11/19 28,800 each sed tOeri 79,344 108,144 111,344
11/22 158,688 _..... eater 12,800 171,488 171,488
11/26 57,600 Bescreadueetnes 52,896 110,496 113,696
11/30 22,400 Recreate ; 52,896 75,296 75,296
12/3 79,344 Cora 132,240 211,584 20584" 7a eee
12/ 6 22,400 Sarsvacaseeneees 54,400 76,800 2O0;800) | wee
12/10 52,896 cae) eee 8,800 61,696 61696." sates
12/14 26,448) a6 2. 2...:: ie 39,672 66,120 66,120 oka ssapemsetees
12/17 aN. renerte oe 2,400 5,600 5iG00)" Pe wrestoaeens
12/20 AG Raa wet Zee. atte 400 46,684 47,484 diyisecovttepee
12/24 4,000 b eSieee aee 3,200 7,200 T5200) (ee eee
12/27 GOO tes eee t 19,836 21,436 21436 3) Pe eee
12/31 4,800 eee hese 12,000 16,800 16,800 sSuaebonseeeee
Macrobiotus Nematode Nematode Total Total

1913 sp. larva sp. Miscellaneous Organisms

1/5 ce ; OF 842 | kee eee
1/ 8 400 960,080

1/12 Shae 1,246,724

1/15 5,194,784

1/19 8,368,732

1/22 3,617,256

1/26 thc Meee ee: oes 4 Weistoss cesses 3,866,856

1/29 ane ies Biesacduceiccrte Im etecere aene 4,629,740

2/ 2 dus es ss e ees 3,563,584

25 4,432,332

2/8 5,301,480

2/12 7,887,808

2/15 5,852,668

2/19 7,185,068

2/23 8,005,224

2/26 11,876,016

3/1 11,583,608

3/ 5 20,691,744

3/ 8 15,302,552

3/12 20,878,430

3/15 7,500,464

3/19 10,894,784

3/23 9,878,580

3/26 7,907,664

3/29 9,781,328

4/ 2 11,109,376

4/5 12,327,488

4/9 . 16,275,928

4/13 .? 11,340,376

4/16 18,041,448

4/19 21,910,608

4/23 26,652,800

4/26 30,783,344 cneoee
4/30 28,879,184

5/ 3 30,505,404 3 che
ay Tf 36,448;208)% © eavcnsrees
5/11 499035136; Yona
5/14 74,895,584 eres crs
5/17 610075202" hve
5/21 50438752" 9 ctor
5/24 52137008 | ahesnc
5/27 83,152,764 = =
5/31 90,298,432

1920] Allen: Plankton of the San Joaquin River 195

TABLE 1—OrGANISMS PER CuBIC METER IN PLANKTON OF
Stockton CHANNEL IN 1913—(Continued)

Macrobiotus Nematode Nematode Total Total

1913 sp. larva sp. Miscellaneous Organisms

(By) Gh eeedasachbocosse ai RENEE ecocserass) | weerehpocaroceasc lalla eaeaeeeeerece 102,283,072

6/ 7 89,267,642

6/11 84,639,968

(BH/TND _. geenatecsecccaso lh ne PER ee so. 35 eC 66,351,588

G/U pease cers ante eer 79,474,408

6/21 wean 1,200,832

6/25 3,200 85,669,652

GPA aehocceeetee | eereeerereges 99) eeecceoeckoocn 105,512,440

WE: 66,694,496...
Ut hee rae 36,946,240

SM I ee heecteeet 32,992,824

TJPA > aestesorcescceus «| MeBoeeecorsoscagy) © ceepenadosecorvou a eckes 48,253,984

THUD. —-pebBcceckeete, = WRERERSEEGAaienede, = Wiaceogonacbocoonys NmumcorEEa wee 485056,792

7/19 6,400 50,284,514

7/23 has 29,064,214

AD = peepee eee 53,158,602

7/30 3,200 38,088,136 _............
Cy Pa) eae a 09,7495616

CY) Oo - ecepbttnscctheenen | McHRERsSeaacceOSOL | cee eRerbs x oMmEreeeDceeepe on 31,442,432

SUP IG): 0 eeeeecec en 3) meeRree ree rec 37,449,228

8/13 71,372,480

8/15 43,499,944

8/20 50,960,344

8/23 49/818,048

8/27 54,312,736

8/31 65,254,556

9/ 2 65,343,280

9/ 6 77,865,920

9/ 9 74,010,912

9/13 TOURS eeececcennte
9/17 62,833,944

OPIN) sb eeiatcas. “DarceSeesctero: A bcqrhocpcooctrpucie weartee nee 53,627,768

9/24 64,570,056

OW ceasacokics. 9 Gtaeaiemens, | cobeaeteecae: “Seocotaes 62,673,664
10/ 1 67,484,896
10/ 4 44,854,524
WO. | ceptsereoctecn |) Cee enekeneis) 9 Goppeaoocecosccct | al AL ancora 58,332,396
OSG rxcersssoree . eines 58,491,488
OWS Sates aces fe: 56,239,096
10/18 52,299,264
10/22 59,089,962
10/26 55,197,450
10/29 : 59,191,148
TL) TM Taare — teen 6,400 6,400 35,026,646
Wi & devezece easter 31,695,424
11/ 8 sees 22,527,832
11/12 47,239,288
11/15 26,993,280
WAG) eee are ere 23,289,272
TWH/2B ——ctecstaaecdeinke, aenesacestuchcce’ 5 aeaaBbosoducacto le eoaecooedenacrean 23,203,120
11/26 115,874,240...
11/30 18,297,984
OH OW gate nave 18,520,416
19/51) = ene ee 13,329,568
DTA OW gas 5,559,302
OA Nearer 7,442,442
TAIN | GetbBeescsecrecs ae | One eorentrrer eos mre cere 6,341,848
£1) /(020) 5 SUNG hl neg cat a an 6,567,456
LH ene ee ES tera) US tre esrveresomi © <eespneneruatsres 3,734,436
TRY, | OR ee ees or Reese ane ero moe eee ee ThelGVSV 4, Ebeacsar tees
2H SG eres ee a en ictess | estes terete Gi209' G32 eeceseeteesrs

196

University of California Publications in Zoology

TaBLe 2.—ORGANISMS PeR Cusic METER IN PLANKTON OF
San Joaquin River In 1913

Spirillum Total
undula

105,792 105,792
105,792 105,792
105,792 105,792

52,896 52,896

Inactis
tinetoria

Gomphosphaera
i Agardh

aponina

Bacteriaceae

Anabaena
sp.

740,544

Merismopedium Microcystis

glaucum

79,344

Aphanocapsa Gloeocapsa Gloeocapsa
sp. conglomerata sp.
79,344

185,136 105,792

PAY ee 370,272

528,960 581,856

634,752 740,544

1,269,504 476,064

317,376 581,856

634,752 793,440

317,376 423,168

12,800 317,376

211,584 317,376

423.168

740,544

528,960

211,584

211,584

12,800

tsi 105,792

Se ae 6,400

‘nates 158,688
52,896

Oscillatoria
formosa

Nostoc
sp. sp.

[ Vou. 22

1920]

Allen: Plankton of the San Joaquin River

TaBLeE 2.—OrGANISMS PER Cusic METER IN PLANKTON OF

Gomphosphaera
aponina

1,600

sp.

San Joaquin RIvER 1N 1913—(Continued)

Inactis
tinetoria
Agardh

211,584
- 634,752
1,692,672
2,115,840
1,269,504
2,115,840
2,327,424
634,752
105,792

Oscillatoria
tenuis

Merismopedium
glaucum

~ 105,792
~ 105,792

Phormidium
spp.

Microcystis
sp.

52,896

290,928
476,064
105,792
158,688
211,584

3,200
105,792

740,544
317,376
105,792
317,376

211,584
105,792
6,400

~ 6,400
1,600
1,600

Stigonema
sp.

Nostoe
sp.

52,896
3,200
158,688
583,456
3,808,512
581,856
952,128
793,440
1,114,016
4,178,784
541,760
317,376
740,544
740,544
317,376
528,960
12,800
12,800
12,800
158,688

Total

Schizophyceae

3.200
52/896
52/896

~ 108,992

197

Oscillatoria

formosa

“105,792
~ 423,168

211,584

423,168

528,960
79,344
211,584
52,896
1,600

~ 25,600

12,800

~ 105,792

Actinastrum
hantzschii

800

52,896

198 University of California Publications in Zoology [Vou 22

TaBLE 2.—ORGANISMS Per Cupic METER IN PLANKTON OF
San Joaquin River 1n 1913—(Continued)

Oscillatoria Oscillatoria Phormidium Stigonema Total Actinastrum
sp. tenuis spp. sp. Schizophyceae hantzschii
; Petr suenees : 3,200 neon be. 59,296 3,200
52,896 Secsssaccseaye ; pandas : 56,096 52,896
1,600 ae noe 52,896 avesensadaterete 325,376 396,720
. Sesracas 1,600 ee . 4° S00K stare saccebneet
3,200 eee aes 64,096 3,200
oe zante barre A 52,896 At Sete
1,600 ee ae ieee sore 8,009 12,800
erreur on 79,344 CELE 185,136 iWeanenesvaeveee
423,168 846,336
Me ; : 158,688 370,272 ‘ he
105,792 = Oy 423,168 952,648 105,792
ah ore lend : : 687,648 1,110,816 : ete
SS 400) ese , : 38,400 618,560 6,400
sieee : Be oe creo Se Ss vesteesd 105,792 323,776 3,200
ae Sts BS csectsotees Site ay 211,584 981,776 79,344
fweshuets gees esha anesasieeds 52,896 267,680 3,200
mesecenegeens sare se. Petes ceeateeke 79,344 3,151,512 185,136
3,200 Serer ateos co Baer ade sees 158,688 6,512,808 ; sess
3,200 Reece Trrremecesares | oe ; 3,864,608 158,688
793,440 _...... Sie FPR ocr 3,200 4,829,536 6,400
105,792 33200) Sans re 6,400 4,624,352 ancposdg enone
105,792 eo ah : 6,400 4,462,464 19,200
105,792 Aco CAO 158,688 beedanceeeene 8,211,680 211,584
PAI US oY eer a eas 317,376 waseetenSecetite 4,773,440 waadeonenees
105,792 Spee eect tains sactanusieese 3,609,728 317,376
ike ahi he AY 317,376 12,800 4,165,288 105,792
es | MS RON MERE ie SU ENON Geo
Peete (acne ates 105,792 Seca nN scen sis 3,596,928 < dantaesbaneeten
ee 12 S00 erie eee . 2,179,840 25,600
Fee agyeeeees. Pe sestyceasteenclss 105,792 647,552 105,792
cree one eae reerase-ue 105,792 753,344 :
ae ete a Ae OTF: Ps HAAN pY
PAs oP a Mpa a, 158,688 S25.440° =. eee
neta = eshosicen sone 12,800 subeaseaaeenses
3,200 105,792 275,680 52,896
sAbtesi Sees sete -Saneetetts 84,144 canaeesecaEee
ae ee 1,600 ; 59,296
Reece S nosbacaru sees: success ene secevautsderres 1,600
Bae serene sete aset Peery ee 3,200
Pie desesstaecs sieves ure monte: cn erohcieeos eae 54,496
1600! 382 : W600" akercctents 57,696
Actinastrum
hantzschii Coelastrum Pediastrum Pediastrum Pediastrum Raphidium
1913 (large) microporum boryanum duplex simplex polymorphum
W/POtey 37s teen 1,200 400 ete
1/12 Pratteresrcen lccecere Vea 800 400 ccevesGeane (eee eeae
/10 ee SS 26,448 9400 ie
WWD MOP Usnzcccccese ae lo diecesteees 19,836 400 400 aecaevsaneieees
2/ 2 Paeeitens 24,000 16,000) 2. sedestons soustaceos meee
2/ 8 51,200 60,800 seacucccsactaete een eee
2/15 41,600 16,000 3,200 sap svank MEER
2/23 79,344 105,792 1,600 Ate
3/1 Booknasnpeaee 48,000 19,200 (reise ; 3,200
3/8 ee oe ee rear a : 132,240 19,200 1,600 1,600
3/15 Sen ate PebAtcc tees 185,136 185,136 eee ss scucsasdeent s
3/23 See Se Aeris 41,600 54,400 1,600 icsunssdantene
BQO © eigticgesseets Ree 28,800 3,200 9,600 105,792
4/5 re See Seer 105,792 12,800 1,600

ANS pee, A ee eal ee oe 35,200 19,200 1600 3,200

1920]

Allen: Plankton of the San Joaquin River

TABLE 2.—OrGANISMS Per Cusic Mrerer IN PLANKTON OF
San Joaquin River in 1913—(Continued)

Actinastrum
hantzschii
(large)

26,448

158,688
317,376
528,960

1,533,984

1,586,880
423,168
528,960
102,400
634,752

1,163,712
740,544

64,000
51,200
25,600

"52,896

Richteriella
botryoides

Coelastrum
microporum,

105,792
317,376
317,376
105,792

~ 105,792

~ 105,792

~ 52,896
52.896

Scenedesmus
obliquus

Pediastrum
boryanum

3,200
158,688
12,800
25,600
211,584
105,792
76,800
51,200
25,600
12,800
25,600
158,688
19,200
6,400
9,600
6,400

Scenedesmus
quadricauda

400

400

400

400
105,792
52,896
1,600
12,800
3,200
3,200
52,896
132,240
211,584

~ 105,792

Pediastrum
duplex

132,240

1,322,400
1,798,464
2,062,944
899,232
1,481,088
2,697,696
2'433,216
2,010,048
2,327,424
2'539,008
1,692,672
4,241,680
4,866,432
846,336
1,163,712
793,440
476,064
89,600
79,344
79.344
19,200
52,890
12,800
52,896

Schroederia
setigera

Pediastrum
simplex

32,000
476,064
25,600
528,960
25,600
38,400
38,400
25,600
25,600
211,584
12,800
52,896

Stigeoclonium
sp.

199

Raphidium
polymorphum

1,600
52,89

1,600
52,896

3,200
3,200
108,992
3,200

~ 317,376

211,584
211584
634,752
528,960

"52,896

~ 105,792
1,600

Total
Chlorophyceae

2,800
1,600
29,648
21,036
145,792
164,896
64,000
201,136
73,600
210,736
427,968
233,040
762,096
121,792
177,792
240,232
321,328
9,600

200

University of California Publications in Zoology [ Vou. 22

TABLE 2.—ORGANISMS PER Cusic METER IN PLANKTON OF

Richteriella
botryoides

“952,128
12,800

105,792
6,400

Asterionella

gracillima
4,535,832
945,516
8,483,196
932,292
9,283,248
9,918,000
1,904,256
2,353,872
819,888
2,274,528
1,005,024
1,930,704
2,512,560
52,896
555,408
687,648
449,616
290,928
2,803,488
158,688
211,584
1,428,192
1,216,608
3,173,760
4,549,056

San Joaquin River 1n 1913—

Scenedesmus

obliquus
3,200
105,792
211,584
3,200

~ 105,792
105,792

105,792
423.168
317,376
211,584
105,792
211,584

6,400

Asterionella
gracillima
(large)

"52,896
105,792

“16,000
105,792
79,344

2,164,736

423.168
3,067,968
2'909,280
4.443 264

Scenedesmus
quadricauda

12) 300

alata

(Continued)
Schroederia Stigeoclonium Ttotal
setigera sp. Chlorophyceae
3,200
528,960
224384
16,000
148,992
277,270
168,288
998,528
2,160,640
3,034,272
2,997,376
1,484,288
4,827,840
8,251,776
5,539,584
5,420,992
ca etanee ee 4,058,496
Bre ern eere 4,371,480
sgtase eee 6,288,960
sos torent 7,212,048
Npitwensaaaee 7,774,016
Se eee 2,397,224
EE ote 2,628,518
piasvdess Rete 1,889,760
Sees 713,248
srenkrostuete 677,856
ihetdes wena 249,232
— 194,736
Feceecs 19,200
1,600 56,096
Se Fst 20,400
Se tects 110,792
Bacillaria Cocconeis Cyclotella
paradoxa pediculus spp.
SOG 2. 0) socetecertccee 687,648
1,200 400 1,031,472
G40 > Ss.kaeccerte 1,533,984
9600) caiinviensseeeess 515,736
81000 ulcers 740,544
12,800 saabomnescabecee 1,295,952
19:200' © ae 1,216,608
9,600 asnee es 2,136,496
fees Si 10,955,872
6,400 6,030,144
25,600 ae OTe 3,967,200
91600) ces riches 3,358,896
6400/0 eee hanes 2,115,840
581,856 Sek sosevougdces 819,888
41,600 sscueseeee 714,096
264,480 iemancasnteenen 1,428,192
ISHS 6m PO sac-snsaeee 766,992
211,584 doesn 846,336
105,792 : é 476,064
3,200 1,269,504
“19,200 3,200 1,110,816
ee 105,792 2,539,008
38,400 25,600 2,856,384
12,800 3,200 1,745,568
19,200 1,600 608,304

1920]

Allen: Plankton of the San Joaquin River

TABLE 2.—OrGANISMS PER Cupic METER IN PLANKTON OF

San Joaquin River 1n 1913—(Continued)

Asterionella
Asterionella gracillima Amphiprora
gracillima (large) alata
4,866,432 ZiIGGZIAG irstcscccsnetanse:
608,304 2EOOG) ) islesestersse
79,344

105,792

"12,800

79,344

1,600

Cymatopleura

Cymbella
solea

affinis

Cymbella
ceymbiformis

800

Bacillaria Cocconeis
paradoxa pediculus
CA ener Losteatis
396,720 1,600
We DAS BAS eee eccertencs
8,569,152
3,702,720
21,528,672
15,392,736
4,760,640
2,062,944
4,972,224
846,336
4,453,264
3,067,968
1,692,672
TASHOSSiS ieeee
528960)" Bates
317,376
76,800
158,688
105,792
19,200 APRs seeree
290,928 1,600
1522110 eee
2,909,280 3,200
2,195,184 weeeee
555,408 1,600
1,216,608 1,600
Cymbella Cymbella
sp. tumida
400
26,445 eth
79,344 ree
3,200 3,200
6,400 aiteeles
52,896 cient
1,600 6,400
3,200
3,200
79,344
185,136
Seth seausesaas 79,344
264,480
Satur eee 76,800
12,800
See eae 64,000
Pieces 32,000
3,200 6,400
RS ree 3,200
3,200
aaesne teas 6,400
3,200

Cyclotella
Spp.
396,720
423,168
1,269,504
5,130,912
10,050,240
10,261,824
3,596,928
3,332,448
9,045,216
14,176,128
14,176,128
14,493,504
15,868,800
11,954,496
17,783,116
49,300,272
42,750,016
31,218,700
8,569,152
3,702,720
3,279,552
1,533,984
1,246,056
795,040
1,216,608
1,904,256
1,190,160

Diatom
unidentified

400
1,600
6,400
3,200
1,600
1,600

1,600
“52,896
1,600
“211,584
105,792
3,200
317,376
"317,376
6,400

202

University of California Publications in Zoology

TasLE 2.—OrGANISMS Per Cuspic METER IN PLANKTON OF

Cymatopleura
solea

6,400

Epithemia
ocellata

12,800
3,200
3,200
3,200
6,400
3,200
3,200

3,200
6,400
105,792
6,400
423,168
51,200
12,800
1,600
11,200
3,200
1,600
6,400
3,200
6,400
12,800
6,400

~~ 12,800

Cymbella

affinis

211,584
105,792

Eunotia
sp.

Cymbella
ceymbiformis

~ 3,200
3,200

Fragillaria
capucina

28,800
132,240
35,200
22,400
79,344
105,792
158,688
158,688
79,344
19,200
19,200
12,800
51,200
19,200
22,400
79,344
6,400
6,400
6,400
6,400
6,400
6,400

Cymbella
sp.

Fragillaria
crotonensis

San Joaquin River 1n 1913—(Continued)

Cymbella
tumida

25,600

Fragillaria
sp.

~~ 1,600

158,688
105,792

"528,960

[Vou, 22

Diatom
unidentified

Gomphonema
constrictum

52,896
"52,896
"79,344

3/200
158,688
317,376

317,376
158,688

1920]

Allen: Plankton of the San Joaquin River

Tasie 2.—OrGANiIsmMs PER Cusic METER IN PLANKTON OF

Epithemia
ocellata

Gomphonema

sp.

Eunotia
sp.

Gyrosigma

acuminatum

"79,344
3,200
105,792

~ 105,792
423,168

25,600

Fragillaria
capucina

105,792
105,792

"25,600

12,800
6,400
6,400

12,800
1,600
3,200
3,200

~ 6,400

Gyrosigma
kutzingii
2,000
1,200
13,224
6,400
52,896
6,400
6,400
3,200
3,200
79,344
79,344
132,240
79,344
25,600
158,688
4,800
158,688
79,344
211,584
158,688
83,200
38,400
211,584
12,800
12,800
132,240
105,792
19,200
264,480
264,480
264,480
317,376
370,272
423,168
423.168
317,376
105,792
25,600

Fragillaria
crotonensis

105,792

Gyrosigma
sealproides

“13,224
1,600
1,600

52,896

“12,800
476,064
846,336

San Joaquin River in 1913—(Continued)

Fragillaria Gomphonema
sp. constrictum

Melosira
granulata

26,448
19,836
30,060
$5,956
608,304
502,512
634,752
1,428,192
343,824
925,680
3,438,240
1,877,808
1,533,984
396,720
3,808,512
7,696,368
a. 6,056,592
Bes 1,243,056
1,586,880

3,491,136

2,274,528
4,866,432
ee 4,654,848
32701552
8,198,880
19,016,112
11,372,640
19,994,688
27,294,336
26,871,168
65,273,664
61,465,152
74,636,256
169,478,784
141,443,904
180,057,984
101,242944
98,809,728
55,646,592

Mastogloia
braunii

204

University of California Publications in Zoology

TABLE 2.—ORGANISMS Per Cupic METER IN PLANKTON OF

Gomphonema
sp.
105,792
105,792

Melosira
granulata A
(small)

5,368,944
1,600
1,243,056
290,928
238,032
52,896
185,136

"211,584

San Joaquin River 1n 1913—(Continued)

Gyrosigma
acuminatum

Melosira
varians

52,896
4,800
39,672
79,344
79,344
44.800
185,136
105,792
158,688
105,792
449.616
264,480
290,928
343,824
185,136
528,960
581,856
502,512
634,752
1,163,712
634,752
1,216,608
793,440
317,376
238,032
449,616
132,240
238,032
105,792
158,688
158,688
158,688
12,800
105,792

Gyrosigma
kiitzingii
105,792
105,792
211,584

12,800
105,792
52,896
6,400
1,600
79,344
3,200
1,600

Navicula
affinis

Gyrosigma
sealproides

Navicula
alpestris

264,480
79,344
105,792
52,896
52,896
1,600
79,344
79,344
79,344
185,136
3,200
264,480
§99,232
317,376
317,376
3,200
3,200
52,896
52,896

“3,200
3,200

264.480
317,376

12,800
105,792

Mastogloia
braunii

Navicula
bacillum

238,032
185,136
185,136
343,824
793,440
634,752
1,005,024
1,322,400
581,856
211,584
79,344
79,344
52,896
105,792
105,792
105,792
158,688

317,376
740,544
211,584
105,792
105,792
211,584
211,584
317,376

[Vou. 22

Melosira
granulata

45,914,928
73,852,864
- 25,505,920
12,483,455
12,007,392
4,178,784
1,481,088
3,041,520
14,176,128
2,142,288
608,304
846,336
661,200

Navicula
didyma

1920]

Allen: Plankton of the San Joaquin River

TaBLe 2.—OrGANISMS PER Cupic METER IN PLANKTON OF

Melosira
granulata A
(small)

Navicula
dubia

San Joaquin RIveER IN 1913—(Continued)

Melosira
varians

211,584
105,792
12,800
19,200
52.896
79,344
52,896
12/800
423,168

Navicula
gracilis

423,168
343,824
264,480
423.168
317,376
793,440
581,856
290,928
661,200

1,745,568

1,586,880

1,110,816

1,216,608
634,752
132,240
185,136
264,480
528,960
423,168
846,336
793,440

1,639,776

2,750,592

3,649,824

3,596,928

2'644,800

1,798,464

1,269,504
846,336
740,544

1,481,088
423/168
423 168

52,896
211,584
52.896
185,136

Navicula
affinis

Navicula

Navicula
alpestris

158,688

Navicula
viridis
400
800
13,224
1,200
3,200
3,200
1,600
6,400
3,200
6,400
6,400
6,400
19,200
6,400
3,200
3,200
132,240
185,136
38,400
158,688
211,584
96,000

~ 105,792
"25,600

"211,584
25,600

Navicula
bacillum

52,896
1,600
52,896
132,240

Nitzschia

acicularis
39,672
39,672
19,836
59,508
185,136
52,896
105,792
52,896
52,896
133,840
105,792
1,600
264,480
132,240
80,944
105,792
608,304
158,688
2,896
105,792
264,480
1,005,024
1,216,608
581,856
528,960
581,856
370,272
264,480
740,544
423,168
476,064
158,688
317,376
370,272
846,336
1,057,920
634,752
317,376
317,376
846,336
634,752
528,960
423,168
264,480
105,792
370,272
52,896

Navicula
didyma

Nitzschia
angularis

206

University of California Publications in Zoology

TABLE 2.—ORGANISMS PER Cusic METER IN PLANKTON OF

Navicula
dubia

Nitzschia
sigma

105,792
105,792
211,584
105,792
105,792
105,792
105,792
105,792
317,376

Navicula
gracilis
476,064
396,720
132,240
185,136
264,480

Nitzschia
sigmoidea

52,896
1,600

3,200
79,344
3,200
79,344

52,896
9.600
52,896
12,800
6,400
105,792

Navicula
sp.

6,400

Nitzschia
sp.

52,896
158,688

343,824
52,896
108,992
423,168
899,232
317,376
214,784
52,896
52,896
1,600
185,136
158,688
3,200
370,272
476,064
370,272
2,539,008

Navicula
viridis

3,200

“3,200

Nitzschia
vermicularis

400

San Joaquin River 1n 1913—(Continued)

Nitzschia
acicularis

52,896
79,344
158,688
1,600
52,896

Pleurostauron
parvulum

238,032
145,464
238,032
522,348
396,720
476,064
423,168
238,032
264,480
502,512
317,376
476,064
581,856
343,824
502,512
132,240
661,200
449.616
132,240
687,648
793,440

1,216,608
793,440
211,584

79,344

317,376
211,584
317,376
105,792
12,800
52,896
2,896
52.896
158,688
132,240
52,896
238,032
158,688
211,584

[ VoL. 22

Nitzschia
angularis

Rhopalodia
gibba

1920]

Allen: Plankton of the San Joaquin River 20

~

TABLE 2.—ORGANISMS PER Cusic METER IN PLANKTON OF
San Joaquin RIvER IN 1913—(Continued)

Stauroneis
phoenicenteron

~~ 3,200

Algae
unidentified

Surirella
sp.

528,960
158,688
581,856
423 168
952,128

2,539,008

4,707,744

1,745,568

2,010,048

2,327,424

1,269,504

1,481,088
846,336

1,163,712
925,128

1,269,504
634,752

1,163,712
423.168
952,128

83,200
423,168
317,376
185,136
238,032
264,480
528,960

Closterium
acerosum

Synedra
radians

476,064
370,272
370,272
105,792
370,272
476,064
1,057,920
1,057,920
211,584
317,376
317,376
423,168
634,752
105,792
317,376
423,168
52,896
52,896
185,136
1,600
132,240
52,896
1,600

,

Closterium
acuminatum

Synedra
ulna

125,6°8

59,508
469,452
178,524
290,928
264,480
238,032
264,480
185,136
370,272
581,856
290,928
370,272
661,200
687,648
502,512
211,584
502,512
819,888

158,688
105,792
211,584
317,376
317,376
105,792
211,584

4,866,432

2,750,592

6,463,312

1,904,256

1,269,504

2.433.216

2.327.424
846,336
634,752
476,064
158,688
105,792
158,688
158,688
317,376
185,136
132,240
264,480

Closterium
rostratum

Tabellaria Total
sp. Bacillariaceae
400 5,809,536
BECO OSES 2,251,768
sgibaseasaseskls 10,974,996
Spee é 2,663,576
peat : 11,996,848
stvceecesdac : 12,933,536
eee 5,016,736
68561748
Bee fcocsenteedat 13,325,744
over aeeeeee 11,019,120
ete 10,801,04 )
reat a 9,134,064
Boeserss tence 14,115,040
aes 5,260,608
ee 8,892,336
14,298,672
11,305,248
7,678,572
ie OG, 10:5051408
Aon meee L696 288
ask PRR 11,764,928
21,702,976
22,407,344
16,107,296
19,785,264
29,834,352
seeece ae cstecee 14,174,332
Be _ 25,030,060
3,200 43,575,008
coe: ; 44,644,352
3,200 102,741,536
Preertcrcen 90,369,664
ees 90,117,192
Seite 193,347,650
eres (80865636
211,605,800
132,958,752
123,920,832
74,461,376
72,648,572
132,110,672
71,980,864
Rope eeectCeee 47,266,700
Be ee 22,980,768
Sarees 10,205,536
5,766,976
6,451,616
18,058,240
11,466,384
6,252,552
sn oiaaieees 4,821,440
NEN 5,190,960

Mougeotia Spirogyra
sp protecta

i004 ri.
a 2,800
200) ae ‘

208

University of California Publications in Zoology

TABLE 2.—ORGANISMS Per Cuspic METER IN PLANKTON OF

Algae
unidentified

Spirogyra

sp
800

San Joaquin River in 1913—(Continued)

Closterium
acerosum

Staurastrum
A

Closterium
rostratum

Closterium
acuminatum

3,200
“211,584

Staurastrum Total
sp. Conjugatae

1,600
1,800
3,200
21,436
ent ae 1,600
< cane 23,036
Y acmen 12,800
8,000
1,600
9,600

Mougeotia
sp.

1,600

Total
Chlorophyll
bearing
5,814,336
2,278,204
13,272,348
3,660,576
13,769,920
16,125,644
8,114,160
9,711,486
14,171,888
11,555,584

[ VoL. 22

Spirogyra
protecta

13,124,668
5,146,432
7,198,124

13,400,944

11,348,448

1920]

Allen: Plankton of the San Joaquin River

Tasie 2.—OrGANISMS Per Cusic METER IN PLANKTON OF
San Joaquin River 1n 1913—(Continued)

Spirogyra
sp.

Staurastrum
A

Ceratium

hirundinella

1,600
52,896
105,792
12,800
158,688
6,400
476,064
211,584
423,168
317,376
211,584
740,544

1,057,920

740,544
211,584
211,584

105,792

~ 1,600
1,600
1,600

Cercomonas
crassicauda

Staurastrum
sp.

1,600

~ 3,200
3,200
423'168
105,792
317,376
423'168
“317,376
105,792
105,792

~ 105,792
105,792

Chlamydomonas
sp.

Total
Conjugatae
3,200
11,200
6,400
252,432

3,200

6,400
3,200
6,400
9,600
12,800

12,800
6,400
17,600
60,896
667,600
392,672
653,952
$38,240
1,205,292
532,160
865,536
5,206,608
817,344
1,836,864
1,599,680
766,144
423.068
660,350
105,792

6,400

62,688
6,400
9,600
3,200
4,800
5,200

80,944

Chromulina

52,896
290,928
978,576
105,792
158,688

Total
Chlorophyll
bearing

11,562,884
10,227,840
16,907,984
5,806,320
9,506,848
14,702,392
11,812,464
8,145,788
10,720,192
17,202,816
12,260,192
24,202,408
24,771,432
17,318,816
20,548,016
31,173,494
15,385,292
30,992,964
58,626,280
60,004,896
114,102,688
100,712,962
101,975,404
214,321,570
196,911,420
226,118,120
148,511,000
137,149,848
90,015,440
90,224,744
147,152,542
84,014,960
58,621,362
29,859,648
14,369,824
11,064,384
13,861,008
22,768,336
16,767,936
9,313,272
7,212,112
6,237,032

Dinobryon
sertularia

1,600
3,200

209

Total
Algae

11,291,504
9,487,296
15,208,872
5,957,008
9,134,224
14,595,000
11,634,576
7,879,708
10,508,608
17,074,624
12,148,000
23,197,384
23,848,336
16,754,656
20,264,432
31,110,998
14,671,196
29,847,700
52,641,128
§2,222,784
111,419,488
97,689,996
99,939,656
210,788,834
193,606,268
221,453,864
143,032,200
133,713,304
85,113,408
$2,463,528
141,298,382
75,340,016
50,145,202
25,702,368
10,931,584
6,836,096
6,791,392
18,321,872
11,490,384
6,316,648
4,901,536
5,440,392

Eudorina
elegans

400
2,800
2,000

800

30,800
22,400
19,200
158,688
22,400
28,800

158,688
502,512
6,400
25,600

210 University of California Publications in Zoology [ Vou, 22

TABLE 2.—OrGANISMS Per Cupic METER IN PLANKTON OF
San JOAQUIN River IN 1913—(Continued)

Ceratium Cercomonas Chlamydomonas Chromulina Dinobryon Eudorina
1913 hirundinella crassicauda sp. sp. sertularia elegans
4/19 erevavecaeeaanes Aucunovsseerees Reraavitiathens. areccr ere siayeseavsvacsss 3,200
4/26 Se Sl ee tee cere | hi cchos cae 02,896 4 wishes saev 16,000
5/ 3 bapepsauibeeeke: eee 6) sont ocean Wyateee patente Maa owactte: wnat SU Gee
5/10 terra: Eiveekswebhvescs Meedcacueanne es enencknaatheeds 58,688) secs
YAN (8 eee weaeeesen Ue) © fasssnets vies hetke . 3,200 12,800 6,400
5/24 6 Neisuniat Reteiscsicesees 105,792 ee etre ccc : 3,200
Dole aes ie RB Sasser Mca hatteaanton* Miteteees seuss eauaed eens
6/ 7 12,800 Src Bee ewes 105,792 12,800 51,200
CVIGR a ow, aaa nt. Wty anaes 264,480 158,688 25,600
6/21 Bae gece ce ero me acaiode error 158,688 3,200 64,000
GY2S it Preece acer Muneee tes cere Sire 3,200
bg PSUR LEAL NSS | PIAS Eee 555,408 105,792
7/12 1,600 cre Srccesussckedte 555,408 502,512
TfL) * Secs digvate ie ae nase eS 5,818,560 44,800
7/26 ee 3,200 tepdlacuaNReets 6,823,584 317,376
SI ul SR OL ie cee 3,200 2,010,048 105,792
8/9 6,400 Feicseui teas auetevsccntes 1,057,920 1,481,088
8/15 hy See ree hate svavexeons soerGarh Awa 1,481,088 6,400
8/23 nog te ar. by een eee 3,200 3,067,968 19,200
8/31 mae 317,376 2:644,800 9 svecsiciens " eeaeceeeaee
9/ 6 sain aces See 3,808,512 211,584
9/13 «fens 4,241,680 38,400
9/20 ee e 2,644,800 38,400
9/27 105,792 4,347,472 12,800
10/ 4 fase eTLORS O84 25,600
10/11 5,183,808 25,600
10/18 TG 22 BUG 9 ascucctds) Plates eee
10/26 8,251,776 105,792
Tale al 3,914,304 6,400 105,792
11/8 2/962,176 105,792 52,896
11/15 3,914,304 52,896
11/22 6,717,792 3,200
11/30 4,231,680 52,896
12/ 6 5,183,808 12,800
12/14 2,988,624 3,200
12/20 2)142,288 3,200
12/27 793/440 « vhencthct | Sika
Euglena Flagellate Hemidinium Pandorina Peridinium Phacus

1913 viridis unidentified nasutum morum cinctum

1/5

1/12

1/19

1/25

2/2

2/8

2/15

2/23

3/1

3/ 8

3/15

3/23

3/29

4/ 5

4/13

4/19

4/26

5/ 3

5/10

1920]

Allen: Plankton of the San Joaquin River 211

TABLE 2.—ORGANISMS PER Cusic METER IN PLANKTON OF
San Joaquin River 1n 1913—(Continued)

Euglena Flagellate Hemidinium Pandorina Peridinium Phacus
viridis unidentified nasutum morum cinctum pleuronectes
Rec secauetscseee 53 105.799 re
6,400
1,600
“79,344
105,792
3,200
Seen essa 6,400
105,792 105,792
211,584 Soesdaastereness
105762 7a.
eee 12 SOO epee
DIU ok eae ah seen Alon wae
105,792 105,792 ore ease
i 5) een 1OSITG20 ay ete
211,584 srctstcatpy | Yesssseseenegesne
BYASNO GO) oapeathecera ne Mblecckenesopoacts
6,400) 7) BO BOG weeny ie
Sree speneee 52,896
6,400 Byarstgl) | nae ene nees
52,896 Kins 1,600
BOOGIE inh Caren dae ee
eS O00KE A cen
GAO OT accesses
Platydorina Pleodorina Pleodorina Pteromonas Trachelomonas Trachelomonas
caudata californica illinoisensis sp. euchlora volgensis

52,896
132,240
79,344
79,344
132,240
52,896
79,344
52,896
132,240
52,896

"211,584

212 University of California Publications in Zoology [Von 22

TaBLE 2.—ORGANISMS Per Cusic MreTerR IN PLANKTON OF
San Joaquin River 1n 1913—(Cotinued)

Platydorina Pleodorina Pleodorina Pteromonas Trachelomonas Trachelomonas

1913 caudata californica illinoisensis Sp. euchlora volgensis
6/28

7/5

7/12

7/19

7/26

8/ 2

8/ 9

8/15

8/23

8/31

9/ 6

9/13

9/20

9/27
10/ 4
10/11
10/18
10/26
11/1
11/ 8
11/15
11/22 1,600
11/30
12/ 6
12/14
12/20
12/27

Trachelomonas Volvox Total Amoeba Amoeba Arcella

1913 volvocina aureus Mastigophora proteus radiosa vulgaris
Lixo 400

1/12 2,800

1/19 2,264,104

1/25 927,280

9/2 1,622,480

2/8 3,000,976

2/15 3,028,528

2/23 2,592,656

3/ 1 ae ay 770,944

3/8 Pas Sesyseeses 8°, Rraansed caste 217,136

3/15 132,240 eer 270,880

3/23 185,136 BS tect: 793,440

3/29 1 G00 Ware sssteers tees 1,699,072

AB om ate IO os SAP ate 166,688

4/13 105,792 ‘ae aeeee 372,624

4/19 B2:896 os Se 107,392

4/26 105,792 ae Sereecoer 177,888

5/ 3 Seas nce ee 266,080

5/10 TEGOOMS cores 211,584

5/17 MOB 792i ekiteaseccveces- 131,392

5/24 agape Panes 112,192

5/31 SPOOL supers 1,005,024

6/7 S17 S7Guae eee 1,028,888

6/16 105,792 cheers 564,160

6/21 F2.896 a eneescis 283,584

6/28 52,896 hee er 62,496

Thy ts) sere : ; Sift 7 V0) one r ee 7 Ml onpcisrcrcetcos: a iecrarctreceoe
7/12 1,400 pe ee 1,145,264 tsteahew, | ashaccsperateese, | | geeaieeee
7/19 3,200 pa ees 5085152 | lL ckakaad 9 Rthatttncc Ueno ieee

7/26 211,584 S50) % S07712) yao

1920] Allen: Plankton of the San Joaquin River 213

TABLE 2.—OrGANISMS PER Cupic METER IN PLANKTON OF
San Joaquin River 1n 1913—(Continued)

Trachelomonas Volvox Total Amoeba Amoeba Arcella

1913 volvocina aureus Mastigophora proteus radiosa vulgaris
8/2 T2800) 2696000) poceecey Sssrotruce

oi): O ae GUC 020366) Cees (ahlk ;

8/15 158,688 PSesteceents 2,035,748 S200M pees ‘

8/23 264,480 6,400 3,644,928 528,960 eens

8/31 423,168 Serene 3,622,528 Tp ee Bei Maes

9/ 6 317,376 4,664,256 QUES SAS) ete: :

9/13 740,544 BELOW GOOI Reed cap, 4h ee eens

9/20 317,376 3,436,544 Brees tie 211,584

9/27 423,168 4,902,032 oe covectaect Seno aerecustenes
10/ 4 528,960 CpG PM) epeeeresccaccese re
10/11 423,168 5,959,952 ah 105,792
10/18 317,376 8,780,736 pace i ais
10/26 211,584 8,581,952 tren gees PASSO) OE a winaeeercecenoercs
iby al 158,688 4,157,280 REO 52,896 Ro eersiits
11/8 211,584 3,438,240 Eekacevavectoess peceenee te er
11/15 105,792 4,281,184 158,688
11/22 158,688 MOSGIGUGIIN Ten os2O0 ec cece: be aps teiotoincoss
11/30 52,896 WAGGA serttee sO ohne,
12/ 6 79,3844 ae TIT AIP 8 ceteresoecee! | | Sepekcrmeeosioa © emmerceclerxtuce
12/14 12600) mate. ce DOGO O24 a ies ccsstese eevee ewe 5 Bs rates
12/20 D2 SOG ers eee 2,310,576 desavacae eee 1,600 Paneer 3
12/27 DE OO Oe cette WOGIGEO) @ nekeeiees g eeeseeriseelees eae

Cyphoderia Difflugia Difflugia Micrograinia Total

1913 ampulla corona pyriformis socialis Rhizopoda
1/5

1/12

1/19 Se
1/25 400
2/ 2 1,600
2/8 1,600
2/15 12,800
2/23 98,544
Cys ll nT eee rater 4,800
SMO aise 12,800
3/15 oa ea
Sy/a) eiesieepeessces 1,600
3/29 3,200
4/ 5 16,000
4/13 omnes 8,000
4/19 52,896 132,240
AV 2Giaee evens 88,096
OV OUR R ere eon tence kere Nelaeae es ne nee
OIE ae rcchcwccvay 1 uth Sadat see eer na
G/T, Nase cepa aes cm: Sate tana, 22,400
VPM eatery whe vai Pe 6,400
EVEN) ene a Tee a ties 634,752
6/ 7 12,800 See rors arenes 104,944
6/15 par Cy Ctr ee aoe 158,688
t /21 Sa 211,584 : Be ireerescor 211,584
6/28 nc 185,136 geetteesseeesiee 0) eaeavens ey 189,936
7/5 secs 158,688 hostel |) We : : 158,688
7/12 3,200 S22400 9 Gieskeciees 1,600 146,640
7/19 aed ee rena, CEES RP ocrCoes 3,200
7/26 12,800 blast einr es 158,688 171,488
SYD) ietcu een. GAO O Degrees es: 158,688 168,288
OY O er eer dts Wi) Givstiicintie: || (wSisavnayetoesis Hoe be chee 3,200
8/15 19,200 3,200 105,792 131,392
8/23 dered ema! | high ee 158,688 1,189,312
8/31 105,792 317,376 211,584 647,552

University of California Publications in Zoology

TaBLe 2.—ORGANISMS PER Cusic METER IN PLANKTON OF

San JoAQuin River in 1913—(Continued)

Cyphoderia Difflugia
ampulla corona
U2;800) ees:
oes 3! “15 $00
ia 12,800
se 1,600

ao enoE iE Heterophrys
sol.

fockei

“12,800 1,269,504
105,792 ‘1,481,088

Difflugia
pyriformis

25,600

Heterophrys
sp.

158,688

Hyalodiscus

sp.

12,800

105,792
52,896
105,792

Nuclearia
simplex

Microgromia
socialis
317,376
211,584

105,792
$46,336
105,792
211,584
211,584

Pinaciophora
fluviatilis

[ Vou, 22

-_ Total

Rhizopoda
567,360
211,584
330,176
131,392
846,336
330,176
211,584

Raphidiophrys
elegans

211,584
105,792
105,792
476,064
211,584
634,752
105,792
105,792

1920]

Allen: Plankton of the San Joaquin River

TaBLE 2.—ORGANISMS Per Cusic METER IN PLANKTON OF
San Joaquin River In 1913—(Continued)

Heterophrys
fockei

2,962,176

Actinophrys
sol.

"12,800

Total
Heliozoa

476,064
423,168
426,368
429,568
317,376
211,584
634,752
144,192
1,388,096
1,586,880
2,962,176
1,586,880
435,968
435,968

317,376
12,800
105,79

Chilodon
sp.

Heterophrys
sp.

Ciliate
unidentified

185,136

~ 105,792

Nuclearia
simplex

Coleps
hirtus

Pinaciophora
fluviatilis
1,269,504
423,168
317,376

~ 52,896
1,600

Cyeclidium
sp.

105,792

3,200
105,792
105,792
105,792

Raphidiophrys
elegans

~ 105,792
52,896
1,481,088

Epistylis
sp.

University of California Publications in Zoology

TaBLe 2.—ORGANISMS Per Cupic METER IN PLANKTON OF
San Joaquin River 1n 1913—(Continued)

Total Chilodon Ciliate Coleps Cyclidium
Heliozoa sp. unidentified hirtus sp.

Euplotes Euplotes Holophrya Paramecium Paramecium
harpa patella sp. aurelia bursaria

105,792
79,344

317,376
158,688
528,960
158,688

is ee
~ 105,792
634,752

105,792
211,584

~ 52,896
52,896

6,400

~ 264,480
9,600

~ 105,792

[ VoL. 22

Epistylis
sp.

sp.

1920]

Allen: Plankton of the San Joaquin River

TaBLe 2.—OrGANISMS PER Cupic Meter IN PLANKTON OF

San Joaquin River 1n 1913—(Continued)

Euplotes Euplotes Holophrya Paramecium
harpa patella sp. aurelia

52,896 MEG OON ay A ere
3,200 foes
Be oe 1,600
Stentor Stentor Tintinnidium Vorticella
coeruleus niger fluviatile longifilum
ite 6,400
3,200
3,200
As 3,200
6,400
6,400
Se 3°00
200
~ 105,792
12,800
= 3,200

Paramecium
bursaria

Vorticella
sp.

132,240

158,688
264,480
793,440
793,440
158,688
105,792
3,200
211,584
211,584
1,057,920
528,960
1,057,920
846,336
793,440
370,272
1,692,672
317,376
952,128
423.168
846,336
528,960
423,168
528,960
317,376

Prorodon
sp.

Total
Ciliata

846,336
1,219,808
1,481,088
1,057,920
383,072
2,115,840
317,376
1,163,712
1,163,712
952,128
846,336
634,752
634,752
342,976
554,560
330,176
487,168
121,792
1.600
60,896
9,600
137,040
6,400

ue
SOI WO OI hore

University of California Publications in Zoology

TABLE 2.—ORGANISMS PER Cusic METER IN PLANKTON OF
San JOAQUIN River IN 1913—(Continued)

Acineta
sp.

~ 105,792
~ 105,792

~3,200

Collotheca
egg, attached

Podophrya Sphaerophrya Total
sp. sp. Suctoria

pee 3,200

6,400

“19,200 ‘19,200

Creare 105,792

c= ~~ 95600 25.600

i eee 12,800 12,800

38,400 144,192

25,600 —-25,600

Peer 105,792

Pe: 3,200 3,200

3,200 3,200 6,400

3,200 1,600 4,800

a ete Ree 3,200

oy W600 | oes 9h MIRGOO
Collotheca Collotheeca Total
pelagica sp. Rhizota

400

without
Mastigophora

800

1,200
6,400
298,928
22,400
261,184
153,040
571,508
110,592
532,912
435,968
319,728
221,184
512,112
307,680
249,232
6,400
395,872
538,560
1,440,992
1,122,768
426,368
370,272
194,736
370,272
367,824
1,907,456
1,017,824
1,811,264
1,929,856
1,724,672
1,889,760
2,974,976
1,519,488
1,519,488
2,907,584
2,683,200
4,799,040
2,551,808
1,307,904
1,214,912
819,040
594,650
2,179,840
132,992
11,200
67,296
16,000
140,240
19,200

Rotaria
neptunia

400
2,400

[ VoL, 22

Total Protozoa Total Protozoa

with
Mastigophora

400
2,800
2,264,904
928,480
1,628,880
3,299,904
3,050,928
2,853,840
923,984
788 644
381,472
1,326,352
2,135,040
486,416
593,808
619,504
485,568
515,312
217,984
527,264
651,752
2,446,016
2,151,656
990,528
653,856
257,232
1,084,368
1,513,088
7,892,608
8,825,536
4,507,264
4,959,222
3,760,420
5,534,688
6,597,504
6,183,744
7,011,088
6,344,128
7,585,232
12,560,256
8,511,760
10,088,640
9,796,864
4,976,320
4,032,896
6,461,024
7,202,608
4,457,664
5,344,848
3,012,624
2,450,816
815,840

Rotaria
rotatoria

2,000
4,400
52,896
26,448
107,392

1920] Allen: Plankton of the San Joaquin River 219

TABLE 2.—ORGANISMS PER Cuspic METER IN PLANKTON OF
San JOAQuIN RIvER IN 1913—(Continued)

Collotheca Collotheca Collotheca Total Rotaria Rotaria

1913 egg, attached pelagica sp. Rhizota neptunia rotatoria
2) a SR cae a.) Pana 57,600
2/ 5 12,800
Dee) eee 79,344
Si) i) NES NY oe ac 32/000
3/ 8 80,000
SUH | | egkee een a? eds 79,344
BY/28) ~ Ber esee ct Sees ipeseoaccocosaecs 3,200 185,136
Sy/PASy, © Greener nese 22,400
LU ihe eee 9,600
4/13 Ben ete
AV MOM eR, Wicnicaeres: |) ccm esas

4/26

5/ 3

TACO: me Rite Se 3 is
I5//ae” VR Seaee © oil Ee, 0 5 Oe EOE it gtkeet > fae Cae 6,400
5/24 : Seeseee npetes ‘ SSarine 5 Wasa 5 ae : 6,400
5/5 rn ee Ao Ac rs ee ee maw’ | ee
6/ 7

6/16 a
6/28 ee see : wacetecev arenes Setedeeaeee sarees 3,200
Gi ees ae Bee: : mie ates phe hae eee ; ahee :
7/12 Fesseaes : : daeaieclés wgectivassvececs Sea EER chop 3,200

7/26 Se eet ee eee eres ; ore : 6,400
8/ 2 Jade os tose ; eine heen Se < 6,400 12,800
8/ 9 .Seneeeeee Pe i 6,400 : : : vk : seseceneieseetets
8/15 83,200 158,688 6,400 248,288 12,800 19,200
8/23 83,200 317,376 Sees tae 400,576 : 6,400
8/31 Cee Seer eae ert ee 12,800 : : 12,800
9/ 6 mee os ee | AGS. vie ees
9/13 12,800 38,400 Rr caters 51,200 :

9/20 wate 51,200 eae 51,200 12,800

9/27 12,800 38,400 veces 51,200 ‘ : : :
10/ 4 128,300 140,800 Soslas eee 268,800 25,600 25,600
10/11 78,800 115,200 Ree ee 192,000 25,600 ee :
10/18 211,584 51,200 + : 262,784 12,800 105,792
10/26 105,792 211,584 ee aerere 317,376 whe : 12,800 ~
yf al sehen: 12,800 : ; 12,800 6,400 12,800
11/ 8 nese 6,400 ee : 6,400 vives : 6,400
11/15 25,600 25,600 4 ; 51,200 6,400 é
11/22 3,200 2000 yee ee 6,400 Raiiecomeens
11/30 : : ean : } ; :
12/ 6 SSC Ssanesedeseucees i fiieesee : 3,200 6,400
12/14 pedsates : ne ae : 3 : : : 6,400
12/20 Pint sPhewecees Fits vane ia ; F : f ; 3 6,400
12) yee, eae eee i at ad

Rotifer egg, Rotifer egg, Rotifer Total Anureaopsis Anureaopsis

1913 winter unidentified unidentified Bdelloida fissa sp.

1 - e eeeen coeen 2,000

1/12 ces é 4,400

1/19 snebierseomeeoece Vases ice 800 54,096

1/25 aeedigesvsii ssthesaiswase 6,000 34,848

2/2 eee ae 6,400 113,792

2/8 pctreas : 1,600 19,200 76,800

OU cc Be Te oe ce 3200 16,000

2/23 3,200 Si scecrecetees 12,800 92,144

3/ 1 Be hoc cee © sparse : 1,600 33,600

Sy tey ” | epesteaseednceen eee 52,896 132,240

220 University of California Publications in Zoology [ Vou, 22

TABLE 2.—ORGANISMS PER Cuspic METER IN PLANKTON OF
San Joaquin River 1n 1913—(Continued)

Rotifer egg, Rotifer egg, Rotifer Total Anureaopsis Anureaopsis
1913 winter unidentified unidentified Bdelloida fissa sp.
3/15 atone “avin sas Bedececeshencace 9,600 88,944 ehecenasemUnSaE Nugakuale PoReaa ee
3/23 Rasveee conse 16,000 ekacesa USS SOO | cases
3/29 SavapeenAerTR UN Uneneenrs ee 3,200 25,600 Spe vesee emer
4/5 spaaweseatescGes is | Brmumtes yesbeedse 6,400 16;000' “won... :
4/13 TOs yaar ‘ 3,200 3,200 Hein : cosdstaceatene
4/19 Sp avineareneiene 1,600 6,400 6,400 Gideneesgrescues) 0 Mevkeseaseencennt
AYV26 |. ssecs sestard 1 G00) veces sedis | “Guseeasyevesvagie 0° WanERANEDTuAccanh 0 cpehenepemeenean
BAOM kacn seaaeea etueseveenaatcs apbansreedscukes
5/10 OO reared : 22,400
5/17 ise ees ee astidencaseees
5/24 12,800 BU veshsxcansias Moateetstcascns
5/31 ae Saket ha treseneae Sisk 12,800
Cae ee, ne Var tino 12/800
Gol mes 3,200
(SHPtes ACPA rESy ful oeestenumretan nm Wins rection
7/5 3,200
7/12 1,600
CLO Ue ATE RORY Mee a tn evar yng incre Ten
7/26

Rie Chon ae ees Ose
Ste S200 eC kn ey SOND

UEEN aly eno Bite ie 12'800
8/31 LOG Die en eran 211,584
SAD ehss: hee a eee 12/800
9/13 25,600 25,600 Pt em ee an
9/20 211,584 224'384 25,600
9/27 105 792 105,792 Berrie cree ssbsaeanneenene
10/ 4 eo eee 105,792 156,992 125800)" » <p
10/11 25,600 38,400 64,000 ree
10/18 38,400 211,584 330,176
TOVZGIG Lint tak he pa uke Geek ae Oe ge 12/800
ile ak B:4000 i neicetwe! Acces 19,200
11/ 8 52,896 12,800 WO200\, mastcnicinntey yokes .
11/15 setsoeacepaverae 6,400 12,800
11/22 1,600 he an eee ete
11/30 tineens 5 adsiveegeey ny) Gdiaaecets. | Gpeees Ro eee eae te ay eee
12/ 6 3,200 DGOD Me rerctecccenres
12/14 3,200 6,400 Ags
12/20 1,600 eer ee 6,400 1,600
QU ZT ON Grates al 3,200 TOO Maye sescxbe nares
Brachionus
Asplanchna Asplanchnopus Brachionus angularis Brachionus Brachionus
1913 brightwellii sp. angularis caudatus budapestenensis calyciflorus
et 2) dae ere ere 800
ee ie alee Sern ne deere han 1,200
IVA ROT Senet niet, nr opeetereeen FM ose eats 1,200
1/25 4,000
SRO er eo ase TN COO meee ¥: Fhe * 1,600
PAT IOWN Malte ane ea tcans Mw eaece ron ts Sdoniiiol sissies ay See tares 44,800
2/15 Meavtenesevarncey GB eEdeseccpveStGun Hsegdetiattiotceel. oh) Giaapas (yeasts emma Mee capeee re 132,240
2/23 tee Sar SER CrRCOs Peer ree eran a es 41,600
Bye Petsewies Patristiem qasectee cece ; ac Susy IPR ioy MAD est eros sexsa-eees ro .-ceereessere 6,400
3/ 8 py 5 Be aerate Bhereaees Ne Yecenseeene 3,200
3/15 Sate cee eee peer Soe tent eee 19,200
3/23 GA0ON es eee 16,000
3/29 i... 9,600 16,000
4/5 6,400 oyxads defi eg Ray yen cankssass45ak MIG Ch ashe cans <cbpecc EnV eseaeeecternedd
4/13 Veeaanere Ao \anstevevcekc cc RMM lr docc etek ogee eee eeceecetaas

1920]

ES ee cae ae

Allen: Plankton of the San Joaquin River 221

TaBLE 2.—OrGANISMS PpR Cusic METER IN PLANKTON OF
San Joaquin RiveER 1n 1913—(Continued)

Brachionus
Asplanchna Asplanchnopus — Brachionus angularis Brachionus Brachionus
brightwellii sp. angularis caudatus budapestenensis calyciflorus
GA00te wo ete 1,600
Fcc EE mR eto CL EMIS To 6,400
SUCHE a any VO key
2) age 6,400
OOO oe ieee wk Coreen ee aes,
Recess res 6,400 oe Secs doccs
Sei, ss sdus Nouseraee 6,400 22,400 Pere ecderre
GOON cect: 3,200 35,200 Seat | ® weiasanceteneees
Rs tes Space: 3,200 105,792 3,200 SEN
3,200 SYA) aesceeasestcocnn 714,096 1,600 sata
Bas ee 1 eos steaes 83,200 19,200 6,400
211,584 OS 92 meee
105,792 19,200 19,200
_.. 1,005,024 12/800 19,200
Seounueshdeees 19,200 12,800 105,792 ee
Le een Real nage 38,400 317,376 Pal ane 25,600
aseeciess 25,600 ee
epee eny | aitecesiebaeates Roe 38,400 12,800
Rist itenn WP otra 12,800 317,376 siteneaesee 12,800
ots 51,200 12,800 25,600
Beet 38,400 12,800 38,400
211,584 12,800
eoaeto | | @aeneeres ret 64,000 25,600
Ee ME TCA BS yt rensccetnie, —— iweadesFeeaeevls 25,600
6,400 25,600 6,400
52,896 Ber ae
Sreimexteae 3,200
eae 3.200 ia ce ae
eee es RAD et 1,600
Brachionus Brachionus Brachionus
Brachionus egg, attached egg, attached egg, free Brachionus Brachionus
capsuliflorus female male female patulus plicatilis
oe ecencnodues |) ceo ee UEeAes Uy PEE useD 800 oases
ete ae ah Pads. 4,000 400
eee rN OW P iSccoecsteonn i coerce eens
Rate Necseeees 400 Sestecosaseae 800 800
Santee: A 1,600 1,600
19,200 3, 200 3 200
Saas: DROS me serene ne eae eee
41,600 6,400 6,400 ears
scarlet © Varadinceeetens 3,200 3,200
3,200
3,200
6,400
3,200
3,200
3,200

222

University of California Publications in Zoology

TABLE 2.—ORGANISMS PER Cusic METER IN PLANKTON OF
San JOAQUIN River in 1913—(Continued)

, Brachionus Brachionus Brachionus :
Brachionus egg, attached egg, attached egg, free Brachionus
capsuliflorus female male female patulus

[ Vou, 22

Brachionus
plicatilis

7 ; Epiphanes Filinia
Brachionus Diurella Epiphanes egg, attached egg, attached
urceus egg, free clavulata female female

Filinia
egg, free

1920] Allen: Plankton of the San Joaquin River 223

TasLrE 2 —OrGANISMS PER Cupic METER IN PLANKTON OF
San JOAQuiIn RivER In 1913—(Continued)

Epiphanes Filinia

Brachionus Diurella Epiphanes egg, attached egg, attached Filinia
1913 urceus egg, free clavulata female female egg, free
6/28 25,600 FOGG ee | Ce 9,600 1,600
Ci G\—eeceeeerene 158,688 seedesadeesGeces sansSseecene Baas Sous ezsattos 1,600
7/12 3,200 WROSIEa 2) 9 eee ar ee sHeseaaess 238,032
7/19 38,400 A76\064 ks, Bits) aw evbaes Taney | \aeauewseceaseas’ seepvioezteveeecs
7/26 12,800 SUTATO- scone pie Cae, Yee er 3,200
8/ 2 105,792 423,168 Sir Seierre) «lis Tice | idee atts 528,960
8/ 9 51,200 USSGSSue eee ee 3.200
8/15 6,400 528,960 12,800 6,400 SoeeecesoDar0 158,688
CUZ ORRN yh fon cak cites : 1,110,816 64,000 12,800 sedasevesvensets 158,688
8/31 38,400 317,376 76,800 ea : 528,960
CG: ae ka aia oe 12800 12,800 Cees
9/13 12,800 952,128 64,000 25,600 Seucsvesieeanss 105,792
9/20 LZ SOON yee Pee 38,400 ae > i elkebesh ee 105,792
VPN (= iene wqeneanes 528,960 38,400 nt cise eerse Be ves 211,584
10/ 4 $46,336 12,800 Here eee 105,792
NOV Ee sesers : 528,960... : ee 105,792
10/18 12,800 105,792 12,800 weesteet nda Soomn teeters
10/26 12,800 25.600) tiscsccdes.
walyf al ere NA een: Wa a caSeweveceeercee (osu ssteotds crthe) (Mo tctcoakdi estan
HES eaten is «hes
Ti (AG) a ee ge Nae UR Pence
OMe Niece, 2 ks OR Tee ae) 0 Tienes
IRIO/S (emer eee cee | cE Ee RS oh
OHMIC Me ret as Sixzseet
12/14 BOOS 9 Bee cercersereceered mec isectecetasccnacs) ) (dexighectSccseeeely jabasce-ces 1,600
WEYPAD) Spence Secaebads® 10 pacccee cee cecetin Me aRScee Sisco scree: Ene see eene te - Ee Seve:
NOP © eSeece eter nse sCEBECESRCEO SS NS EC Sa
Filinia Keratella Keratella Keratella Keratella Lecane
1913 longiseta cochlearis egg, attached egg, free quadrata luna
1L//) Gy = eeecocesecaeen ANDO Besar sivaveses 1,200 1,200
1/12 oss 1,200 800 2,400 1,200
WAS 5 40005 oe > : 1,200 19,836 1,600
1/25 200M ecess= RE 33,060 1,200
2/ 2 oe oe 3,200 1,60 17,600 20'S O00 meee
2/8 asedon SRU ETO 6,400 16,000 132,240 22,400 eee rere
2/15 estes 12,800 6,400 132,240 6,400 3,200
2/23 79,344 99,200 25,600 6,400 6,400 wb ceceeeseenes
3/1 57,600 32,000 112*30 0 eed Meee :
3/ 8 290,928 238,032 158,688 Sesvexts : 19,200
3/15 44,800 211,584 52,896 ae 9,600
3/23 38,400 555,408 211,584 1,600 79,344
3/29 28,800 264,480 79,344 132,240 158,688
4/5 3,200 264,480 1,600 79,344 19,200
4/13 3,200 105,792 1,600 79,344 28,800
4/19 Seer OCEN Cee 793,440 1,600 185,136 105,792
4/26 Sees eee 132,240 1,600 3,200 41,600
byl 83 1,600 6,400 weviv eee uneesion 1,600 79,344
5/10 6,400 aecANN | eesecee erect 3,200 44,800
5/17 sivapasesseseree 38,400 __..... Maeacatad 105,792 3,200
5/24 Boer eeeeceeeee OE re ene SestcSes 3,200 12,800
5/31 12,800 12,800 ero 105,792 38,400 ree ;
6/ 7 genis dudasseeece 38,400 Ra 105,792 Pe : 12,800
6/16 oe 32,000 6,400 3,200 158,688 Pen 3
6/21 6,400 211,584 9,600 158,688 9,600
6/28 57,600 238,032 79,344 1,600 Peas es Sie 5
Ue 3,200 555,408 watateted steven 185,136 12,800 6,400
fe 9,600 1,798,464 eaesedebtewnyse 423,168 3,200 :
HEOE cheats . 634,752 wsdevendesecesss 211,584 57,600
Uj. ere eee 25,600 6,400 ere 12800 Fees

224

University of California Publications in Zoology

TaBLe 2.—ORGANISMS Per Cuspic METER IN PLANKTON OF

Filinia
longiseta

striata

San Joaquin River 1n 1913—(Continued)

Keratella
cochlearis

158,688

12,800
1,269,504
2,115,840
2,486,112

846,336
476,064

Polyarthra
trigla

800
2,400
1,200
2,000
12,800
57,600
19,200

6,400
12,800

105,792
3,200

12,800

6,400
3,200
105,792
12,800

Keratella
egg, attached

105,792
25,600
105,792
317,376
793,440
528,960
12,800
185,136
52.896
6,400
6,400
6,400
3,200

Polyarthra
trigla egg,

Keratella
egg, free

3,200

211,584
211,584
317,376

6,400

Polyarthra
trigla egg,

attached female attached male

Keratella
quadrata

12,800

Synchaeta
sp.

[ VoL, 22

Lecane
luna

Trichocerca
capucina

1920] Allen: Plankton of the San Joaquin River 225
TABLE 2.—ORGANISMS Par Cusic METER IN PLANKTON OF
San Joaquin River 1n 1913—(Continued)
Polyarthra Polyarthra
Notholea Polyarthra trigla egg, trigla egg, Synchaeta Trichocerea
1913 striata trigla attached female attached male sp. capucina
9/ 6 317,376
9/13 Z es :
OV 2) 2 S00 eS SOO ie ecencey) |) Sexcecrercsecess) © (oausteserene 12,800
9/27 12,800 Serre are
10/ 4 eee te ee
10/11 siacattvesdiest eee occas 12,800
10/18 211,584 115,200 211,584
10/26 acnetemccders 320,000 edt
ial// al 264,480
11/ 8 317,376
11/15 51,200
WIV BPA) GASH) rcrestonatrntes © Beceeacecocosdae O270900 ace
11/30 22,400
VLG 79,344
12/14 atte 79,344
12/20 1,600 105,792
WAPPA — ceemcesceene 9 | @aZAUIU 7 eerarecrctce Perec 79,344 1,600
Trichocerca Total Total Bosmina Bosmina
1913 iernis curta Ploima Rotifera longirostris sp.
ly! Gh") eeeaee secs ne peeaeee eee 5,200 T2000! aesectecesateces? © besences
TU /AIP}. ee eats 0 Mees ein ree 15,600 20,000
IAG EE oe en PLE ore 27,436 81,532 mee
WV/25) 45,060 80,308 800
2/ 2 73,600 197,392 eee
2/8 308,240 385,040
2/15 516,816 532,816
2/23 380,144 472,288
Sy Al 168,000 201,600
3/8 937,632 MOGO%528) | akcweerves 0 waseavanereeeces
3/15 737,152 826,096
3/23 1,022,432 1,210,768 nae
3/29 733,952 COE YEGV 4 = cesrecasecccos saws
4/ 5 403,024 ANQIODA: © ceicesccct 6,400
4/13 286,032 287,232 3,200
4/19 1,106,768 WUT B GSS cecceoseests aeescess eats
4/26 293,184 298 SS ee Hace 1,600
5/ 3 100,144 100,144 3,200 nee
5/10 147,200 G9! GOD ee -ee cote eee
5/17 150,592 156,992
1 PALS ey ee ee eee 200,888 DOG GSSy mcescoss ees |e cee eee
5/31 182,592 1O5S92 © Whee
6/ 7 208,192 2201992) a cicseces
6/16 277,088 277,088
6/21 464,672 467,872
6/28 eer 687,168 690,368
7/5 3,200 1,002,480 1,005,024
7/12 eee 3,573,584 3,578,384
7/19 setts 1,297,728 1,297,728
i 26m LODE 92) eee ee 560,768 567,168
8/ 2 Bote 1,213,216 1,387,904
8/ 9 6,400 579,968 579,968
Slo 44:800 ‘%..... ; 1,378,112 1,690,400
SSL DS OS SU mmr re cre seeetee 782,052 1,201,828 Seer peee scp
8/31 1,573,312 1,810,496 12,800
9/ 6 eidecsstotiast «lh © teveverdee 1,067,328 1,067,328 StS cae os
9/13 76,800 1,441,920 1,518,720 76,800
9/20 211,584 903,552 1,179,136 51,200
9/27 128,000 685,184 $42,176 25,600
10/ 4 64,000 794,368 1,220,160 12 SOON eee

226

1913
10/11
10/18
10/26
natal
11/ 8
11/15
11/22
11/30
12/ 6
12/14
12/20
12/27

1913
1/5

University of California Publications in Zoology [Vou 22

TaBLE 2.—ORGANISMS Per Cuspic METER IN PLANKTON OF
San Joaquin River 1n 1913—(Continued)

Trichocerca
lernis

64,000

sp.

Trichotria
eurta

Total
Ploima
637,376
2,830,016
3,185,792
3,949,312
2,168,736
565,664
$11,040
427,872
154,544
239,536
159,440
98,544

Total
Cladocera

102,400
51,200
51,200
12/800

"12,800

Total Bosmina Bosmina
Rotifera longirostris sp.

893,376
3,422/976
3,515,968
3,981,312
2,194,336
629,664
SI74GD) ee
ADT: S72)
164,144 3,200
245,986 veces ae
165,840) - 2 eee
101,744 6,400

Canthocamptus Cyclops
sp. sp.

105,792

38,400

1920]

Allen: Plankton of the San Joaquin River

TABLE 2.—ORGANISMS PER Cupic METER IN PLANKTON OF

Chydorus
sp.

Total

131,792
118,592

San Joaquin River in 1913—(Continued)

Sida

Total
Entomostraca

169,792
51,200
12,800
38,400
51,200
12,800

6,400
6,400
3,200
6,400
6,400

~ 6,400

Total
Cladocera

Chironomus
larva

Canthocamptus

sp.

Glochidia

Cyclops
sp.

~ 400

227

Nauplius
sp.

Macrobiotus
sp.

~ 400
~~" 2,400

University of California Publications in Zoology

TaBLe 2.—OrGANISMS PER Cusic METER IN PLANKTON OF

Nematoda
sp.

San Joaquin River 1n 1913—(Concluded)

Oligock
sp

laete

Water
mite

Total Total
Miscellaneous Organisms
5,821,536
2,299,404
13,356,680
3,751,684
13,983,312
16,816,012
8,672,576
10,530,652
14,529,728
13,204,020
12,502,272
12,027,616
18,115,104
6,880,048
10,023,664
16,330,872
12,421,328
8,507,964
10,896,192
17,784,480
13,031,040
25,877,192
26,220,984
18,035,072
21,395,760
32,071,398
16,780,444
34,980,772
61,889,064
61,589,888
117,489,648
103,235,586
105,448,076
217,550,950
201,760,892
229,022,312
12,800 151,795,800
Beiter Ss 141,406,360
: 93,592,016
96,256,744
150,741,918
88,902,832
63,576,626
34,666,400
17,158,816
13,933, 184
14,814,640
23,213,808
17,005,776
9,575,208
7,518,192
6,370,776

[ Vou. 22

1920]

Allen: Plankton of the San Joaquin River 229

TABLE 3.—OrGANISMS Per Cunic METER IN PLANKTON OF
SmituH’s CANAL IN 1913

Spirillum Total Anabaena Aphanocapsa Coelosphaerium Gloeocapsa
undula Bacteriaceae sp. sp. kiitzingianum conglomerata

INGOOT mesa teneteey La ecemeree ete i
TRGOOI i exe Une es
3,200
SLOT de Geant fy ig Samara ete ae
GT): Pe eel Sen ees. ee ares,
SIO Mm men one
TOO Mes hy periee Male Anta coe | cn aa
SO 0k" QURAN ete panieaes came Bae
3,200 LOST 02 a
9,600 3,200
28.800 79,344
476,064 185,136
3,200 52,896 ie ae
2,036,496 264,480 185,136
4,601,952 1059700) Ae Mier ee oe ene
4,125,888 6/450 meen 105,792
793,440 ZO SUTS) ouneeee he 6,400
GOT GIGMe a ING 712" mt ce 158,688
1,586,880 158,688
AS TROSS MMe
1530) 00Samaae
1,692,672 211,584
ee 528,960
T'S 00h pei ee hee ata
12,800

PAS He WS ore hinccna | = eemey se ncenesce

Inactis
Gloeocapsa Gomphosphaera tinctoria Merismopedium Nostoe
sp. aponina Agardh glaucum sp.

University of California Publications in Zoology [Vou 22

TABLE 3.—ORGANISMS PER Cupic METER IN PLANKTON OF
Smitu’s Canau 1n 1913—(Continued)

Inactis
Gloeocapsa Gomphosphaera tinctoria Merismopedium Microcystis Nostoe
sp. aponina Agardh glaucum sp. sp.

eet 3,200

pear ci toa Oa ee 304/384
[COO Mot ea we 158,688 2,062,944
290,928 52,896 Beir Retr ce Seine 264,480 581,856
DiGEYE ae ha Gul etl sae os eo 211584 ‘1,110,816
$46,336 oo; 200 eevee shiins crates 370,272 687,648
476,064 eS ae secede systveaeisasees 211,584 1,216,608
1,269,504 1052702 An mee ene a ae 211584 — 1,322/400
S876) settee ee A o
581,856 —..... Readies 1,163,712 Fore 2. 32,000 6,876,480
317,376 sacuueatvoxsrece 6,030,144 Prensete : 12,800 3,491,136
423,168 Sutin cee 7,934,400 12,800 12,800 740,544
1,057,920 76,800 952,128 Paani es turers 64,000 1,057,920
952,128 317,376 1,586,880 __..... aoa 12,800 2,644,800
(40,544 eseeesecs we GL OUON7a4a” © fas vitesse 25,600 634,752
740,544... ates 423168 .... ite 317,376 317,376
317,376 orehstdatyncsass 528,960 swaasussecassepe 211,584 317,376
pone att dl tents ; ; 317,376 has iiies ace 20; G00) eee
6,400 acagevediva Ress SRO EEE OTe Pehastosics 6,400 6,400
52,896 BScaras : ae : ssvategleteiee 6,400 12,800
158,688 signentesceaves 52,896 528960 meee . 12,800
105,792 Bere erreeeecetc 132,240 52,896 acacsteaseaeeee
BORDEE gtr nema | Bae cet 52.896 12/800
52,896 ..... fee oe 105,792
Cee le CPR, SAAT
LE OOO lessee Saees teanebetecseiiee OO Raines |e Deliecisses = Meet aoe
1335840 eee Srey GA. Po ecrocer acd ose
Oscillatoria Oscillatoria Oscillatoria Phormidium Stigonema Total
formosa sp. tenuis spp. sp. Schizophyceae
400 SPENT s tenes ERATE eM ON ee Ne pecscts eet 400
erases ape Serer cre Meervere sce 3,200 ieetebesdscceas 3,200
es Re. ee 400 66,120 ganesh seeeerens 66,520
eee aed vectarcnsee cree 1,600 eeescoue Ses done 1,600
mee Bre 1,600 DB; 200) a ere 7,000
79,344 52,896 : 135,440
Rcranticrs 185,136 188,336
1,600 Seite ee 4,800
Pasiereccens ite ERO ML euatteare aes 1,600
52,896 52,896 re restr 110,592

Geasteoerseeet? 79,344 ef awe eric 150,288

SPICE STs ICSE Paar Ae ae SUZ SHOye creas 476,064

or
bo

1920]

Allen: Plankton of the San Joaquin River

TaBLe 3.—OrGANISMS Per Cupic METER IN PLANKTON OF
Smitu’s Cana in 1913—(Continued)

Oscillatoria Oscillatoria Oscillatoria Phormidium Stigonema
formosa sp. tenuis spp. sp.

OSA ARE nats ceeene
132,240 searaneeanee

16,000
1,600
AORN sy Aeeieee acl ae nO 1,600
5 Re ee TRGOOKI ices cme es 1,600
1,600 1,600 SOOM EK ee 52,896
3.200 Sm SHG)» Magee LL eee eee
a ; S70 DMR eS ee 6,400
ae eae SAS TOI ee ee ees
6,400 CS TAGAS MEER hee ee) a 158,688
211,584 3,200 476,064
SiG cacenree UP ARe
ate 105,792 Bie OE ae
Pee tee aaehee * 317,376 211,584
1054702 ee 528,960 ies O°

1,600 not
: 3,200 52,896
Seseeeereeces 52,896
ek Sc 1/600
9,600 eee ;
nee 52,896
Actinastrum
Actinastrum hantzschii Coelastrum Crucigenia Pediastrum
hantzschii (large) microporum lauterbornii boryanum
poet cas a ae Ree ess seas 400
6,400
6,400
19,200
Bc basctotewe ae : fee 32.000
Bee re eouys ce tree 51,200
3,200 Lapeer Rico ies sees 38,400
1,600 aredrateNe RS ee Peco 105,792
1,600 weet hath Neots Meeectt rican tery ieee 158,688
1O5t0O MS PR ce 79,344
9,600 Pree crret ta cee : : poe 158 688
158,688 Resse ene aer es tegcstassenietsd seactvaps ceties 132,240
3,200 ae ore tect Socne : ee 158,688
52,896, Pecectant eres eatenaent F vaveguatesteare 12,800
1,600 oe : site sa eeerreret cea 105,792
105,792 26,448 nese ee Pea eras 79,344
Bereereaave : 9,600 iss boxesttteset lesstueciuateeees 132,240
6400) 28. MT ee Oe 22.400

231

Total
Schizophyceae
250,832
140,240
110,592
163,488
68,696
9,600
84.896
1,600
3,200
123,392
120,944
132,144
758,800
2,130,240
3,735,568
6,562,304
6,780,294
2,651,200
7,623,424
323,726
41,252,352
13,554,174
11,662,720
5,218,716
6,571,904
13,880,992
1,824,064
1,599,680
355,776
25,600
230,784
283,680
295,728
174,688
158,688
132,240
135,440
9,600
52,896

Pediastrum
duplex

400

7,200
79,344
9.600
79,344
132,240
9,600
6.400
79,344
132/240
132,240
158,688
105,792
22,400
105,792
79,344
12/800

University of California Publications in Zoology

TABLE 3.—ORGANISMS PER Cuspic METER IN PLANKTON OF

SmituH’s Canau in 1913—(Continued)

Actinastrum
Actinastrum hantzschii Coelastrum
hantzschii (large) microporum
1,600
6,400
158,688
185,136
9,600
52,896
19,200 423'168
6,400 264,480
EA caer Sibel Ben oe
105,792 793,440 158,688
5 Fever 3,067,968 423,168
634,752 211,584 528,960
ae ae 211,584 1,057,920
105,792 211,584 528,960
die BRgssecteths 952,128 211,584
423,168 1,481,088 105,792
teen eaees 1,481,088 25,600
Be eters GH EPSNAGhie @ Lareecnrcece: 3
6,400 20448058 eee
seaganseaieess 105,792 6,400
6,400 52,896 52,896
1,600 Devindaneeeec oe MN eee eet eee

Pediastrum Raphidium Richteriella
simplex polymorphum botryoides

1,600

132,240

1,600

ee ide 1,600

52,896 1,600

Ew TE 54,496

1,600 79,344

plahie be 3,200

300m en
3,200

¢

Crucigenia |
lauterbornii

"528,960

Scenedesmus
obliquus

Pediastrum
boryanum

~ 158,688
19,200
211,584

105,792
211,584
105,792
211,584

51,200
211,584
317,376

19,200
211,584

6,400

Scenedesmus
quadricauda

400
3,200
400
1,600
3,200
105,792
79,344
6,400
132,240
9,600
132,240
290,928
105,792
158,688
132,240
105,792
6,400
3,200

3,200
6,400
132/240
3.200
9,600

[Vou. 22

Pediastrum
duplex
12,800
1,600
6,400
25,600
105,792
22,400
211,584
396,720
925,680
1,851,360
1,481,088

185,136
105,792
52,896
52,896
9,600
52896

Schroederia
setigera

1920]

Allen: Plankton of the San Joaquin River

TABLE 3.—ORGANISMS PER Cuspic M&TER IN PLANKTON OF

Pediastrum
simplex

1,600
52,896
32,000

6,400
105,792
105,792
105,792
158,688
105,792
528,960

12,800
211,584
25,600
12.800
211,584

Total
Chlorophyceae

1,200
9/600
14,000
100,144
48,000
237,936
257,984
129,792
302,128
280,480
388,864
795.040
431,168
174,688
316,528
479,264
389,472
125,744
27,200
19,200
118592
180,240
116,992
211,584
746,944
597,856
1,644,576
2,593,408
2,577,408
2,548,508

SmityH’s CANAL In 1913—(Continued)

Raphidium
polymorphum

"224 384
211,584
105,792

Asterionella
gracillima

773,604
6,083,040
3,153,924
5,183,808
9,997,344
2,062,944
2,644,800
1,666,224
1,481,088
1,295,952
1,137,264
3,702,720
211,584
793,440
343,824
581,856
28/800
3,623,376
608,304
185,136
105,792
819,888
2,353,872
3,067,968
899,232

Richteriella
botryoides

“105,792
~ 952,128
25,600

Asterionella
gracillima
(large)

1,600

158,688
~ 132,240
52/896

2.803.488
3,120,864

Scenedesmus
obliquus

158,688

12,800
423.168
211,584
105,792
423.168
105,792
423.168
211,584
317,376
211,584

Amphiprora
alata

Scenedesmus
quadricauda

264,480
105,792
290,928
158,688
317,376
476,064
370,272
899,232
528,960
846,336
1,163,712
528,960
846,336
1,269,504
2/115,540
1,692,672
846,336
1,110,816
1,216,608
846,336
687,648
290,928
158,688
6,400
3,200
1,600
52,896

Amphora
coffaeformis

Schroederia
setigera

Bacillaria
paradoxa

1,428,192
1,904,256
5,183,808
4,760,640

234

1913
8/9
8/15
8/23
8/31
9/ 6

9/13

University of California Publications in Zoology

TaBLE 3.—ORGANISMS Per Cuspic Mrrer IN PLANKTON OF

Total
Chlorophyceae

2,194,336
2.168.736
4,562,256
6,042,944
7,606,924
6,068,548
6,674,876
6,292,928
9,222,112
9,133,712
4,337,472
3,466,640
3,355,248
1,811,264
1,112,416
579,408
364,624
67,296
59,296
12,800
242,832

Cocconeis
pediculus

Smiru’s CANAL IN 1913—(Continued)

Asterionella
gracillima

Asterionella
gracillima
(large)

1,600

Cyclotella
spp.

146,264
1,560,432
958,740
1,137,264
1,481,088
1,798,464
6,506,208
16,794,480
6,109,488
4,839,984
3,491,136
4,496,160
1,322,400
1,745,568
3,358,896
2,062,944
3,782,064
1,533,984
2/248,080
899,232
581,856
819,888
1,295,952
1,560,482
3,649,824
3,226,656
5,316,048
7,405,440
8,410,464
10,367,616
6,823,584
7,669,920
13,594,272
14,281,920
12,906,624

Amphiprora

alata

“211,584

105,792
105,792

Cymatopleura

solea

25,600

Amphora_
coffaeformis

12,800

Cymbella
amnis

[ Vou. 22

Bacillaria
paradoxa

14,493,504
3,200
2,062,944
1,057,920
423/168
1,798,464
6,241,728
2/221,632
2,327,424
740,544
423,168
211,584
105,792
102,400
28,800
370,272
290,928
1,613,328
740,544
502,512
264,480

Cymbella
eymbiformis

1920] Allen: Plankton of the San Joaquin River 23

TABLE 3.—ORGANISMS PER Cupic METER IN PLANKTON OF
SmituH’s CANAL IN 1913—(Continued)

Cocconeis Cocconeis Cyclotella Cymatopleura Cymbella Cymbella
1913 pediculus sp. spp. solea affinis cymbiformis

9,521,292
15,128,256
17,773,056
22,765,328
22/342) 160
24,667,584
39,407,520
13,488,480

6,559,104

2,697,696

2,540,608

2'196,784

2,327,424

1,297,552
Z ioe ne URRORE
DON, eR ts Oe MNS A 1,719,120

~~ 12,800
~ 105,792

52,896 .
. 6,400
6,400 12,800
ene 3,200
1,600 12,800
1,600 3,200

6,400

Cymbella Cymbella Cymbella Cymbella Diatom Epithemia
1913 pusilla prostrata sp. tumida unidentified ocellata

12,800

ie BGA) = ome eee w kar ene
ive: 5 G00 meen ee ted

1200 R) Ronis |
12800), Ahem 12,800

ol

236

University of California Publications in Zoology

[Vou. 22

TaBLE 3.—ORGANISMS PeR Cupic METER IN PLANKTON OF

Smitu’s Canau in 1913—(Continued)

Cymbella
pusilla

Cymbella
prostrata

Cymbella
sp.

Eunotia Eunotia

Fragillaria
flexuosa sp.

capucina

1,200
9,600
19,836
9,600
6,400
52,896
16,000
9,600
79,344
79,344
22/400
185,136
79,344
79,344
6,400
158,688
9,600
12,800
12,800
19,200
1,600
3,200
28,800
105,792

~ 12,800

ate eee 054702
105,792 12/800
"52,896
52,896

9,600

Cymbella
tumida

Fragillaria

crotonensis

~ 105,792
105,792
105,792

unidentified

Diatom Epithemia

ocellata

Fragillaria Gomphonema
sp. constrictum

400.0 aseaercrneets

1920] Allen: Plankton of the San Joaquin River 237

TABLE 3.—ORGANISMS PER Cusic METER IN PLANKTON OF
SmityH’s Cana In 1913—(Continued)

Eunotia Eunotia Fragillaria Fragillaria Fragillaria Gomphonema
1913 flexuosa sp. capucina crotonensis sp. constrictum
11/22 6,40) SSLOOM jeaeadeeee nreccneseiense
DU SOME ae tctetesstecs, |v Wizetienkiteons || (ttcscchey BS wedtecesteine ; ahs 1,600
12/ 6 3,200 ee
1OVEMMONGOO,, fen.
1D — “RAVING 8 Mee oat w (GR en ts. ik Mann See. ORnne a
12/27 1,600 SO00n nn
Gomphonema Gomphonema Gomphonema Gyrosigma Gyrosigma Gyrosigma

1913 olivaceum sp. subclavatum acuminatum kiitzingii scalproides
T/A os Gercpeseorcer cen. Wie sansa ee ceo e name ERA ro Cee BP a ee ete ore AQQ se ee are ee
Tile) PSS: eee MEN in be 3,200

1/25 pe RO 800

Bi D.Sc * Ue t amenn c hs ene 6,400

OUECME En RRL Sect We eR REN 6,400

SUS" ia tt a 2 ee A OR 105,792

y/o Seam ie ebtetitrs Mier erin, |) as 3,200 3,200

SAL DR TNO acetic © eu cst Toes 52,896 UDG Pare seteecocc

SU) S| Uae WA ke te a ee mene

S/T). ees Poesees Freee 3,200 1,600
3/23 3,200 132,240
SOGmee RIE ot. 9 eee: 1,600 132/240 1,600
4/5 ThGOU MES SEE Ria oe PRY Wi tes
LUND Bese ENE ole re ie eee |e, Ra 1600 ee

4/19 79,344 1,600
UCAS 6, Lopenptlrescteee ap Neer eRe rt et chart 6,400

DOU hee S200 Rete ners

DV MOMMMER mr acest | Macittreeiace Oo DOO Es (eh eee
§/17 1,600 1,600 1,600
By: ager ADRS Cit ee a nan a 12,800 3,200
5/31 Seiieseaseee ROE ere ee A BSE ae ae Tie
6/7 TCO): | eeeeeae, Wey, aT ee eae eadiohe 12,800 52,896
6/16 Sate ee ON eee co reetetees Wesaiervse as 12,800 aairerersa neds
GPA epee eee : ese eee ee eer Baer eetareees 9,600 1,600
6/28 shbesecberteore sid ae Sree rete eey j : 12,800 1,600
Tiss | tte eee ete ea tere 1,600 000) ee aa
7/12 a Spebastkocedy "|e Peace 105,792 Leer aaecds
7/19 Me regs | Paes ke ae SZ 000 arene
TH EAB > Sees ne oa pA le aa pe et : cee eu era 476,064 6,400
CHD brn, whirek nese SONA 158,688 317,376
8/9 So 7k Ai ; 211,584 1,481,088
8/15 211,584 105,792 1,005,024
8/23 105,792 370,272 2,697,696
8/31 Bee 211,584 317,376 1,586,880
9/ 6 al 105,792 423,168 740,544
9/13 eee 211,584 317,376
9/20 317,376 105,792 317,376
9/27 ee moe ee 12,800 211,584
OVE: hese ebairede eae aera TOSOOM | atc 105,792 317,376
10/11 pees ee Be Meee ate 105,792 Peco nec 38,400 211,584
OVC Wee a a LOS R7ODMEs eee ey Uinta 105,792
10/26 bene diccrtecr es cheeses ce ee 12,800 423,168
TULL" eaeecesencsessg) Me ceRiAteeskerssceg am Lu rceeaseiynrttiset ll MPa natn tne sees eR Bree 6,400
11/ 8 105,792 158,688
TL AUS" Weeeepcaeee Seen ee eee eae 6,400 79,344
YOON cee WV) aveaten tc 52,896 132,240
WSO. Tiveoseaee! | hanes eee 6,400 3,200
2 MG Mercere Oo as Sebo 52,896 52,896
TPA oe Ray cet eat ceri le ge ee Re ae nes O2S9O0 © cise :
WRAD ) Viseres tacenace im meer nace 6,400 52,896
ODT MMMnren: eke hele yee | IAs t REREAD Caesieckeessevoee 3,200 105,792

12/20
12/27

1913
1/11
1/19
1/25
2/2
2/8

University of California Publications in Zoology

TABLE 3.—OrGANISMS Per Cusic METER IN PLANKTON OF
Smitu’s CANAL IN 1913—(Continued)

Melosira
granulata

1,600
119,016
449,616
952,128
899,232

1,560,432
687,648
1,084,368
4,152,336
1,877,808
2,353,872
872,784
5,104,464
5,765,664
9,203,904
1,560,432
2;010,048
3,649,824
3,279,552
1,454,640
5,078,016
6,426,864
8,119,536
14,652,192
9,891,552
16,503,552
13,647,168
24,437,952
34,170,816
64,321,536
86,643,648
84,845,184
88,971,072
193,810,944
75,439,744
127,912,576
72,265,984
53,214,576
60,524,224
27,515,968
22'057,632
15,445,632
6,612,000
2,697,696
2,115,840
3,914,304
2,327,424
1,507,536
661,200
1,110,816

Navicula
didyma

Melosira
granulata A
(small)

6,321,072
9,045,216
132,240
740,544
634,752
581,856
211,584
158,688
105,792

Navicula

dubia

Melosira
varians

4,800
211,584
19,836
9,600
25,600
264,480
9,600
264,480
105,792
185,186
423,168
396,720
105,792
158,688
9,600
238,032
79,344
105,792
79,344
19,200
3,200
6,400
79,344
132,240
6,400
185,136
158,688

211,584

317,376
105,792
12,800
105,792
6,400
6,400
19,200
3,200
52,896
6,400
79,344
52,896
25,600
185,136

Navicula
gracilis

~ 800
158,688
158,688

Navicula
affinis

105,792

79,344

Navicula
sp.

52,896

~~ 1,600
1,600

Navicula
alpestris

“105,792

Navicula
viridis

[VoL. 22

Navicula
bacillum

79,344
105,792
52,896
132,240
3,200
3,200
52,896
52,896
52,896
1,600
52.896

105,792
211,584
105,792
211,584

1,600

Nitzschia
acicularis

59,508
185,136
158,688

1920]

Allen: Plankton of the San Joaquin River

TABLE 3.—ORGANISMS PER Cupic METER IN PLANKTON OF
SmiryH’s Cana In 1913—(Continued)

Navicula
didyma

Nitzschia

angularis

Navicula
dubia

6,400
~ 105,792

"52,896

Nitzschia
sigma

Navicula
gracilis
264,480
6,400
290,928
185,136
290,928
290,928
476,064
581,856
185,136
238,032
608,304
105,792
132,240
158,688
211,584
317,376
370,272
79,344
185,136
1,600
634,752
105,792
1,798,464
740,544
2,062,944
49,722,240
3,385,344
2'644,800
1,904,256
423,168
2,327,424
1,375,296
952,128
1,163,712
740,544
317,376
52,896
158,688
52,896
185,136
158,688
370,272
158,688
185,136
317,376

Nitzschia
sigmoidea

Navicula
sp.
79,344

105,792
82,544
3,200
1,600
1,600
4,800
6,400
1,600
3,206

~ 3,200

~ 3,200
6,400

3,200

Nitzschia
vermicularis

1,600
3,200
52,896
105,792
9,600
3,200

1,600
6,400

Navicula
viridis

“12,800
“12,800
6,400
6,400

is 12,800
~ 12,800

Pinnularia
acrosphaeria

Nitzschia
acicularis

132,240
79,344
158,688
79,344
105,792
211,584
343,824
238,032
264,480
264,480
476,064
52,896
105,792
211,584
185,136
132,240
211,584
846,336
661,200
1,005,024
819,888
608,304
793,440
687,648
793,440
634,752
158,688
423,168
3,067,968
3,385,344
1,269,504
528,960
1,481,088
528,960
211,584
211,584
105,792
158,688
317,376
502,512
211,584
290,928
502,512
132,240
79,344
132,240

Pleurostauron
parvulum

39,672
317,376

72,732
264,480
211,584
158,688
211,584
740,544
290,928
476,064

240

University of California Publications in Zoology

TABLE 3.—ORGANISMS Per Cusic METER IN PLANKTON OF

Smiru’s Canau 1n 1913—(Continued)

Nitzschia Nitzschia
angularis sigma
S200 us Pe creracteane
SyZ00 9 eens
12,800
3,200
3,200
3,200
3,200
6,400
ae er 3,200
1200) eee
1,600 1,600
CTC) eee aoe
9,600
25,600
6,400
105,792
6,400
12,800
12,800
TD QOOUE a te tees
re: 12,800
TE RO0k er eee
Abse: 52,896
52,896 12/800
cans 1,600
3,200 6,400
2000) ee ape
3,200 52,896
Rn P4:, 52,896
9,600
3,200
Stauroneis Surirella
phoenicenteron sp.
400
17,600
5,600
65,600
19,200
Dei eiear ier 114,544
94.496
132,240
48,000
158,688
132,240
185,136
132/240
185,136

"3,200

79,344

Nitzschia
sigmoidea

Synedra
radians

Nitzschia

vermicularis

~ 105,792
158,688
~ 105,792
105,792

Synedra
ulna

26,448
449,616
469,452
343,824
238,032
343,824
396,720
502,512
290,928
793,440
238,032
476,064
370,272
528,960
423,168

Pinnularia

acrosphaeria

Total

Bacillariaceae

995,988
8,850,184
4,882,644
7,847,616

13,286,048
6,526,064

11,554,384

21,603,120

10,066,896

12'653,248

15,174,656

23,028,112
5,009,024

10,329,424

11,761,264

[ Vou. 22

Pleurostauron

parvulum
370,272
423,168
343,824
581,856
211,584
132,240
211,584
211,584

52,896
158,688
158,688

3,200
158,688
105,792
158,688

105,792
52,896
52,896

211,584
52.896

1,600

105,792

132/240
52,896
52,896

185,136

Closterium
acerosum

1920]

Allen: Plankton of the San Joaquin Rwer

TaBLe 3.—OrGANISMS PER Cupic M&TER IN PLANKTON OF °

Smiry’s CANAL In 1913—(Continued)

Stauroneis Surirella
phoenicenteron sp.

“1,600 ——-132,240

3,200 79,344

211,584
105,792
132,240
449.616
211,584

1,428,192
687,648

4,125,888

3,200 ‘1,586,880

2,274,528
1,163,712
634,752
211,584
634,752
528,960
423,168
317,376
740,544
634,752

cee 476,064

52,896 528,960

52,896
185,136

158,688
3,200 264,480
ae 105,792
264,480

79,344

Closterium Closterium
acuminatum rostratum

Synedra
radians

528,960
423,168
423,168
317,376

1,586,880

1,269,504
846,336
634,752
158,688
158,688
264,480
211,584

52,896
52,896

~ 132,240
1,600

Cosmarium
sp.

Synedra
ulna

185,136
6,400
317,376
185,136
105,792
1,600
132/240
238,032
238,032
1,190,160
343,824
343,824
158,688
267,680
211,584

370,272
158,688
4,125,888
3,808,512
5,924,364
2,856,384
2,539,008
1,904,256
2/291632
1,692,672
476,064
370,272
528,960
158,688
79,344
132,240
290,928
238,032
105,792
185,136

Mougeotia
sp.

Total

Bacillariaceae

14,915,728
6,323,232
8,531,408
8,256,480
5,198,768
2,285,728
8,722,096

14,880,432
17,599,024
22)537,552
15,092,112
26,131,376
24,800,128
43,673,600
53,816,832
95,438,688

149,512,496

113,258,240

118,406,848

220,996,096

96,437,784
157,322,752
99,961,216
84,452,672
89,303,502
57,291,968
64,325,240
30,671,584
15,042,976
6,757,696
6,35 ,424
7,324,400
13,506,832
7,003,072
3,890,112
4,581,056

Spirogyra
protecta

241

Closterium
acerosum

6,400

1,600
79,344

“185,136
6,400

242 University of California Publications in Zoology [ VoL. 22

Tasie 3.—OrGANISMS PER Cusic Meter IN PLANKTON OF
SmituH’s Cana In 1913—(Continued)

Closterium Closterium Cosmarium Mougeotia Spirogyra Staurastrum

1913 acuminatum rostratum sp. sp. protecta A
5/31

6/ 7

6/16

6/21

6/28

TUS PRIA ee FRR Re) = ins Seine rc ae

7/12 238,032

7/19 211,584

7/26 423,168

8/ 2 264,480

8/ 9 1,322,400

8/15 3,200 3,200
8/23 3,967,200 105,792
8/31 4,866,432 re citteg (eaten ees
9/ 6 L5S6G80) ames 211,584
9/13 317,376 ONS REET ES CE 423,168
9/20 1059792 ee 3,067,968
9/27 ce 25: 317,376
NO OR eee ey tte rear | eee reer 105,792 423,168
OVW cae ket, SMR Eee eee, eee Mere ee ee 3 528,960
10/18 i caG, Y Vek ohne 25,600
10/26 5 2,896)e ees ceeces , 264,480
11/1 See ie 12/800
11/ 8 adeats Year em Sa
DALEY Ww Sac cesees feece mt econ Sec coet ane ce PADS o a ECE Uc ceer crs
WU QO 42 lies berawesen Bs homtactiean: 1m apna 52,896 3,200
11/30 1,600 3,200
12/ 6 3,200 3,200
ie ae eS a ey | 3,200 1,600
QV 2O0 MN. cstsiaeeiee, — Wee owe Maliaintteery VER eee eee
WOV2 A ce a AE Oe ae eee 6,400... soe

Total
Staurastrum Total Chlorophyll Total Ceratium Cercomonas

1913 sp. Conjugatae bearing Algae hirundinella crassicauda
1/11 slissensse ete 1,200 999,988 998,788

OUT eaSere tees 8,000 9,938,504 8,870,984 See irikes feexe ae sei
258 see 3 3,600 6,508,748 4,966,764 Serene See casa ceon teen
DRG) oe ee 4,800 9,223,664 7,955,760 9 occ... 1) ee
2/8 1,600 17,480,488 13,842,648 .......... est oes RO
AAS ah Me eer tec? ; 4,800 = 10,570,064 6,904,240 eae renames coshecesceuecos
2/23 Site 84,144 17,567,024 12,084,848 sievvescecyuseve 7) Cokseeseoe eee
Sf a ea DOUTBT- ARB ia OTe To 77s een
3/ 8 eine 191536 WE OS0N28) 105625160) ae Soe: Aenea ccs
3/15 siiieaissteeee 12,800 18,969,056 18,057,120 .......... siaxhe ge Soensscseeeenes
3/23 eer. sore 100,000 17,638,720 15,813,808 —.............. eS Pink eee
3/29 as aeeaasteupetes 52,896 25,649,664 24,352,112 jeauieceuae sadseactanasbage
4/ 5 vd Sap neaie ae 12,800 5,868,912 5,703,824 ...... ,

4/13 es 3,200 11,054,624 10,647,552 seca)

4/19 rn ee woo 12,431,216 12,188,384

4/26 camer toes 8,000 16,141,088 15,566,480

Syl 8} eee Seas ices nee 7,444,200 6,781,400 ERO NCON

5/10 Saapeer Draavine 1,600 8,998,528 8,668,352 aicsbusisestavy, Oheaweye dewistane
bey be Os fens 3,200 8,540,968 8,371,776 Peatecerere ot) ikseteenttaees
5/24 epistasesccnaaie 3,200 5,364,608 5,222,768 pOetacaece: cones Seichasaneqettee
5/31 =cpeeeee : 1,600 2,574,208 2:409\120) © | ke Sistasve, G | CHeeRAGayeE
6/ 7 ; ~ S 9,600 9,462,448 9,035,328 nvesviceeteean Wl uitecsen ren
6/16 ¢ sezitone 9,600 15,295,408 15,127,968 estvaaksscresdes 3,200
6/21 sSvaneegeenauees 4,800 18,320,928 17,949,056 Pecprethuot ec 3,200

6/28 a eared 52,896 24,406,320 24,096,192 tess 3,200

1920] Allen: Plankton of the San Joaquin River 243

TABLE 3.—ORGANISMS PER Cusic METER IN PLANKTON OF
Smiry’s Canat 1n 1913—(Continued)

Total
: Staurastrum Total Chlorophyll Total Ceratium Cercomonas

1913 ‘ sp. Conjugatae bearing Algae hirundinella crassicauda
(Ce ROMMNN ectecteceneoes es 108,992 19,267,600 = 17,929,200

Ci See ; 383,072 33,831,696 31,896,192 eeecesst ae

7/19 211,584 435,968 36,948,320 28,391,808 6,400

7/26 105,792 Go2OZMOSHiOONlde, DS'GS4 2540 irsnvctecce) | cecearesssseetes
8/ 2 317,376 694,048 62,336,096 59,710,588 Beer cs eo

8/9 105,792 1,789,368 111,133,112 107,045,816 = iN

sing Eee 115,392 161,112,670 152,120,350

8/23 317,376 4,508,960 138,246,256 133,585,008 ck crices tees recep nite
8/31 BP esc vsncvie ve 4,917,632 147,390,462 142,921,598 pieces See 105,792
9/ 6 528,960 830,144 247,981,772 241,201,676 iethins ; et est eee
9/13 Resco vasslas 859,136 114,001,764 108,584,184 12,800

9/20 ee 3,199,362 177,590,200 173,768,894 Berane seas Reese
9/27 105,792 423,168 125,264,912 120,058,304 susstees < 105,792
10/ 4 Sessa ce 488,960 101,844,780 95,987,808 moractecerrries , seo
10/11 554,560 104,095,892 100,591,454
10/18 237,184 65,078,784 62222400 .........
10/26 330,176 70,077,512 68,147,656 52,896
11/1 19,200 38,316,112 34,276,816 Renee ae tres
11/8 ne DIPS Tey Oo
11/15 214,784 = 11,703,204 8,382,224
11/22 62,496 16,219,536 7,168,016
11/30 Aekereeorrre 14,000 11,808,016 7,861,712
NOG aarerare pe 9,600 16,429,664 13,715,968
12/14 HT Es ce 11,200 =: 10,081,776 (G21 OGOSis Messrs cy ee Coe ees
12/20 Des : 6,232,912 3,912,512
12/27 6,400 7,511,136 4,883,184

Chlamydomonas Chromulina Cryptomonas Dinobryon Eudorina Euglena

1913 sp. sp. sp. sertularia elegans viridis
WA ae) TO an pee meen 1,200

1/19 acactasotveeses 1,005,024 ae aes Aes ee 8,000

DD Re nei ee seacies 1,500,924 Ponte meeene cS ce 3,200 ee ;
PHP) Pe ceaateosaness 952:128 —s..... Henne ; 105,792 52,896,
2/8 52,896 3,782,064 —..... Sees bandeaekecreeee G'000 eee severed
Tila. temo On SHON eee fe 9,600 3,200
DPOB ge Ne sexes 5,527,632 Botiaset : 3,200 32,000 6,400
3/ 1 sacivigivovaete 846,336 Rect ee chee S saneateeene oes 44,800 Po ae
3/ 8 ee 105,792 DS chenseuwa ease : 35,200

3/15 eadensuxesttews 396,720 Seetiets 5 1,600 60,800

3/23 Sroieie nies 1,322,400 ee : Bate 211,584

3/29 esters tie 634,752 —.....: sestyctes 1,600 264,480

Loi a ee 5 TOBA ee ak, aoe B50) a .
4/13 Aree eeey 158,688 =... : 1,600 32,000 3,200
4/19 Pepssiteiseserss 185,136 ; ; Sere S200) eee :
UPSD eee : 238,082 SSce Eanes a : 12,800 1,600
5/ 3 SCARED 290} 928 wages ere O289G— kee tk : :
5/10 Pesistsbesencass 105,792 Eee 6,400 1,600
5/17 Bssdentn a 105,792 wae : 49,000 __..... Ss
§/24 1,600 TEG OOK Beticcccses eee 3,200
5/31 ivactvaeseate ae ; S200 fesvcntecns
6/ 7 teeth, 52,896 Paes, PASO) 8 eases
6/16 (eye ee 22,400 3,200
6/21 105,792 tee WQ/S44 seeks
6/28 1,600 16,000 Rootes
7/5 793,440 6,400 52,896
7/12 1,401,744 185,136 79,344
7/19 2,486,112 51,200 3,200
7/26 3,702,720 105,792 158,688

244

University of California Publications in Zoology

TaBLe 3.—ORGANISMS Per Cuspic METER IN PLANKTON OF

Smitu’s CANAL IN 1913—(Continued)

Chlamydomonas Chromulina Cryptomonas Dinobryon
sp. sp. sp. sertularia

oe HERDER). astivekacae
VM TIT Mise yre 9 = pene
8,569,152 eae
EOS 'GR0) see a eras
3,279,552
5 15 Shae LON 792 We eee
a re SiOTSOLG Ativensctast | omeestteaes
ee _ -2'750,592 bie iat
Svedstee aaeeves 4453-204) | gochey See rate.
LOR EB SOL LOG) Mae eee eo ne
eacbee aie ee aeate 2,644,800 eecesnacnorerere Wonansweshiuens
ae Peng GRa mse
os aes orrelt: © eee i
Di438:240) DP iiscsseees neh eo ee :
4,601,952... coe 52,896
3,094,416... a an ee Whe
8,727,840 1,600 3,200
DE Panerai: 3,623,376 52,896 52,896
Neha ers O12 ROM wee cles 3,200
pe CoE 2'962,176 1-GOOls Garters eee
(EIS 6 5059 104, mere oem
Ba pie 2,486,112 SS PeceERe es
Flagellate Hemidinium Mallomonas Pandorina
unidentified nasutum sp. morum
welicbeageenes 1,600
2'400
22,400
ceptaawdecsntts 3,200
4 eens wae 25,600
Perera 6,400
eal Ree errr 9,600
PRO cys cyyoetteays: 132,240
el mee ste Sa 79,344
TS Oe PORES TEE Sy ee 105,792
Oneal eed ale tag see 3.200
1,600 3,200
1,600
1,600
3/200

ae Ata SER
264,480

Eudorina
elegans

32,000
1,163,712

25,600

105,792
3,200
22,400
9,600
52,896
52,896
9,600
6,400

Peridinium
ecinctum

[Vou. 22

Euglena
viridis

sp.

1920]

Allen: Plankton of the San Joaquin River 245

TABLE 3.—OrGANISMS PER Cusic MBTER IN PLANKTON OF

Smirn’s Cana ry 1913—(Continued)

Flagellate Hemidinium
unidentified nasutum

528,960

105,792
105,792

Peridinium Peridinium
cinctum sp.

105,792
211,584

Phacus Platydorina Pleodorina Pleodorina

Syncrypta
1913 pleuronectes caudata ealifornica illinoisensis

volvox

51,200
76,800 12/800
12/800 105,792

246 University of California Publications in Zoology [Vou, 22

TABLE 3.—ORGANISMS PER Cupic METER IN PLANKTON OF
Smitu’s Cana IN 1913—(Continued)

Phacus Platydorina Pleodorina Pleodorina Pteromonas Syncrypta
1913 pleuronectes caudata californica illinoisensis sp. volvox
10/11 ‘
10/18
10/26
iat
11/ 8
11/15
11/22
11/30 1,600
12/ 6 ,
12/14
12/20 ae eae es Fe cotati ee
12 DAs cee | Aen Seam Meee
Synura Trachelomonas Trachelomonas Trachelomonas Volvox Total
1913 uvella euchlora volgensis volvocina globator Mastigophora
TLD yee ite! ae Re eee 1,200
TAO Perv pattie eV onsdremeiee ete ete 52,896 1,067,520
1/25 AQDO Nesters 33,060 1,541,984
2/2 iy J ie wa Wea 3? 105,792 1,269,504
2/ 8 52°80G 99s. Seen 211,584 4,137,840
2/15 52,896 290,928 3,665,824
2/23 1,600 ease 79,344 5,682,176
3/ 1 52,896 79,344 1,029,776
SV ashi) Beeectetescs.) — eaeeecees 317,376 467,968
3/15 105,792 211,584 911,936
3/23 132,240 79,344 1,824,912
3/29 105,792 105,792 1,297,552
YY Ep) ent CE ECE ORI Aidit Eg 228 165,088
4/13 158,688 52,896 407,072
4/19 52,896 1,600 242,832
4/26 132,240 132,240 574,608
5/ 3 132,240 662,800
5/10 105,792 330,176
5/17 1.600 169,192
5/24 79,344 141,840
5/31 105,792 165 O88
(ay! Ze 52,896 427,120
6/16 1,600 167,440
6/21 79,344 373,472
6/28 158,688 : 310,128
af 5 370,272 einucewnessets 1,338,400
7/12 264,480 setcsanstevanacs 1,937,104
7/19 zs ae Dee rcs 2,556,512
LU PAT memes Pee 581,856 ei eects 5,053,920
8/ 2 x ae Retr ewceskees 2,625,408
toy ney Btaseoae Sees 528,960 Rectusscseceest 4,087,296
8/15 ae 423,168 ese 8,992,320
8/23 105,792 317,376 poe Renee 4,664,448
8/31 Pattie: C40} 544 rex 5 4,468,864
9/ 6 105,792 634,752 12,800 6,885,888
9/13 wna 1 schatess Ae cd she 5,417,600
G/ 20g) sens eoee OLA SOM me Mesrersccosscesre 3,821,306
9/27 423,168 Padeca ie caiases 5,206,608
10/ 4 ae 317,376 eae 5,856,972
10/11 12,800 211,584 ern e 3,503,936
10/18 oe eee Beene wat 2,856,384
NO/26 ue eee ee AE SBE sa tecteess 1,929.856
anf al 211,584 4,039,296
11/8 ee 211,584 5,084,416
A eee ree oe ee aceon) fe Nona eut 211,584 3,322,600

1920]

Allen: Plankton of the San Joaquin River 24

TaBiLe 3.—OrGANISMS PER Cuspic METER IN PLANKTON OF

Smity’s Canau 1n 1913—(Continued)

Synura Trachelomonas Trachelomonas Trachelomonas
uvella euchlora volgensis volvocina
Soaneegeneaeres 211,584
1,600 185,136
1,600 132,240
Shecces. 52,896
eee ces? 52,896
3,200 132,240
Amoeba Amoeba Arcella Cyphoderia
proteus radiosa vulgaris ampulla

~ 105,792
~ 423,168

"105,792
52,896
52,896

Difflugia

Volvox Total
globator Mastigophora
9,051,520
3,946,304

3,200 2,713,696
2,872,768
2,320,400
2,627,952

Difflugia
corona globulosa

ba |

University of California Publications in Zoology

TABLE 3.—OrGANISMS Per Cuspic METER IN PLANKTON OF
Smitu’s CaNnau In 1913—(Continued)

Difflugia
pyriformis

Heterophrys

fockei

Hyalodiscus

sp.

"317,376
317,376
105,792

Nuclearia
simplex

Microgromia

socialis

211,584
317,376
105,792
528,960
211,584
105,792
264,480
105,792

52,896

Pinaciophora

fluviatilis

Trinema
enchelys

5,501,184

~ 105,792

Raphidiophrys

elegans

Total
Rhizopoda

3,200
800
1,600
12,800
28,800
11,200
4.800
11,200
87,344
6,400
6,400
16,000
17,600
213,184
348,624
79,344
32,000
79,344
140,800
266,080
138,640
105,792
105,792
331,776
241,232
220,584
6,400
124,992
12,800
12,800
5,501,184
448,768
647,552
2,022,848
422,168
740,544
118,592
753,344
317,376
211,584
476,064
264,480
105,792
1,600

Total
Heliozoa

[Vou. 22

Sosaopawe
sol.

Ciliate
unidentified

1920]

Allen: Plankton of the San Joaquin River

TaBLE 3.—OrGANISMS PER Cupic METER IN PLANKTON OF
SmituH’s Canat 1n 1913—(Continued)

Heterophrys

fockei

Nuclearia
simplex

Pinaciophora
fluviatilis

Raphidiophrys
elegans

Total
Heliozoa

249

Ciliate
unidentified

~ 211,584
211,584
211,584

~ 105,792

423,168
317,376
2,962,176
211,584
105,792

Cyclidium
sp.

"317,376
317,376

Didinium
nasutum

528,960
423/168
158,688
105,792

1,600

Euplotes
harpa

105,792

79,344
264,480
423/168
317,376
687,648
105,792

211,584
211,584

Euplotes
patella

1,005,024
211,584
423/168

423,168
541,760
3,173,760
1,798,464
634,752
476,064
211,584
799,840
1,218,208

Halteria
grandinella

~ 3,200

Hastatella
radians

250 University of California Publications in Zoology [Von. 22

TABLE 3.—ORGANISMS PER Cuspic METER IN PLANKTON OF
Smitu’s Cana IN 1913—(Continued)

Cyclidium Didinium Euplotes Euplotes Halteria Hastatella
1913 sp. nasutum harpa patella grandinella radians

9/13 105,792
9/20 105,792

Paramecium Paramecium Prorodon Stentor Stentor
aurelia bursaria sp. coeruleus niger

4/5 105,792
4/13 105,792
4/19 1,600

1920] Allen: Plankton of the San Joaquin River 251

TABLE 3.—ORGANISMS PER Cusic M@eTEeR IN PLANKTON OF
Smitu’s Canau 1n 1913—(Continued)

Holophrya Paramecium Paramecium Prorodon Stentor Stentor
1913 sp. aurelia bursaria sp. coeruleus niger
4/26 So COG a RI I ee 3,200 3,200
Gist © eee a SOE, Cir Ty oe 3,200
YM). aan Bis ovas are
5/17 3,200 3,200
5/24 D2 SOG hy Peete cc maeneee PSM aivlestiesstan, — 5 prasabagaetlenne
5/31 TE GOO Wan aeeererereren Wk cecce een esc .cccn crys sseces 8 ahdunticacsias. lassgteteabees
6/7 THEO OWE Prins coos mean a ee a
6/16 GOO) S reeeteess, Me catiteteecn h) aeeichscveds | esidiebeveccaugy. —- savnecarsatenev
6/21 LE GOO GM Rr erence te ae cies
6/28 LE GOO terete recente res etiees | tetacescsasd: dete Ae
7/5 RolnnGm Wena) ONE pn
7/12 20 (Coe OE ee dene Lae
7/19 GAOO PRM cccetets, | ricivxenige, | assets
7/26 Sy eee me ME neem Sse ckisic, | Aakieestetaaast. © LEGS eae
8/2 105-702" ee ANG Meehan) le
8/9 OHA Vion oe eR TCI OML GREECE GB. Benito
Siilsiie ns eee te
SYGR. Tabi Meets \AURMNED sie ease nae MOS 7O2is uot Aw ay Geen
8/31 DUNS B84 S ) occseiees ees : Drsceveiwascers | vtecedses Xe
oye “904056 | re CN re i a eee
9/13 493168) = 9 t isasesvocts 5, | SBS etonicocn, eas ececeecis: mn un ceRePe eee ec seine Nem ror ppecoernsceon
9/20 211,584 seseesseseneeees
9/27 12,800 Aosecseneeeee Esecit haireycones woneeecereae
10/ 4 740,544 dceganieee ease severe) ©) \2ee Se,
10/11 317,376
NOM fe, OS el ae gota
10/260 ne. ee. Ra cinch! Se ae pee
11/1 105,79 ss, , | Re ea
11/ 8 158,688 D5GO0se cee 52,896
T/A eee : : 16,000 19,200 Tee)
11/22 WGO0N ace: O00) eR ot ined
11/30 IR GOO Reece See eee anes se atteteent
12/ 6 OV SAAS Me ntciccesstils, O Neetneeeiie p Bincvliacse 5 Gattdecte
12/14 BH OISOG Rm I, ple PUNT MIN Tis BOSE 8 OATES ee
12/20 52,896 Cees eel heen eNom Mon inaecheeracy 3,200 3,200
12/27 3,200 1,600 avenseassueelds 52896) 0 eee 3,200
Tintinnidium Vorticella Vorticella Total Acineta Sphaerophrya
1913 fluviatile longifilum sp. Ciliata sp. sp.
SF AUN Sapa o techie 2e (We Geesrsceraesiees ee
VOR eieescvcccosie) | poexseresatcetis moor
WOKE ee a 2.400
DEE i 1,600
2/ 8 HEGOOW as.ctisteeees 11,200
Diem ek ee 14400
2/23 3,200 28,200
Sve. Sadie oe 8,000
3/8 ais tacts 25,600
3/15 3,200 72;096
3/23 1,600 48,000
3/29 ae 12/800
4/5 108,992
AU IUS MMe nce Rae “Usccice vedo 1,600 120,192
CASA) i a eee 1,600 6,400
4/26 1,600 113,792
He en ee 1,600 4.800
IO. Vectecceoseaean, uncer se 105,792 105,792
LAU, ee ert es eee oot 158,688 168,288
5/24 3,200 158,688 214,784

252 University of California Publications in Zoology [Vou, 22

TABLE 3.—ORGANISMS PER Cuspic METER IN PLANKTON OF
Smitu’s Cana 1n 1913—(Continued)

Tintinnidium Vorticella Vorticella Total Acineta Sphaerophrya
1913 fluviatile longifilum sp. Ciliata sp. sp.
DONE) | acecctancoenion| eeetsereseanenaes 238,032 239,632
VA ti Bae 211,584 213,184
6/16 Sane apepeeeaad 211,584 213,184
6/21 3,200 449,616 454,416
6/28 6,400 423,168 440,768
VEO Pesicceccovatavson. = ieee cyte iss . 581,856 634,752
TALS; 9 Aeacsdssvatessey | © @uesieiveaot> 793,440 1,084,268
ELOY 0 perststertee ae Aaah enoscneve 581,856 588,256
eS O gM aeanossckseeee been scees aces : 952,128 955,328
62/71 ees eee eee ee eee 1,533,984 1,639,776
S/NOT cS cietee Geceeniven : 952,128 1,166,912
8/15 sestecessntuaes 3,200
8/23 105,792 211,584
8/31 1,798,464 2,327,424
9/ 6 634,752 2,551,808
9/13 211,584 952,128
9/20 846,336 1,269,504
9/27 634,752 804,544
10/ 4 423,168 1,282,304
10/11 528,960 964,928
10/18 740,544 740,544
10/26 581,856 618,856
LATA 16 400Ws 14,22. 35. ; 105,792 249,984
11/ 8 Senta ate 158,688 408,772
11/15 ipeisrevachae 52,896 261,184
11/22 3,200 3,200 108,800
TU/305> 7 G00. eee : 132,240 148,040
12/ 6 S600)" cexeuscus: 5 130,544
12/14 a Nravesnesieeevs 3,200 1,600 59,296
ADP 2O) | resesecsers Boe mee fe Pe sos 79,344 138,640
12/27 9,600 1,600 1,600 73,696
Total Protozoa Total Protozoa :
Total without with Collotheca Collotheca Collotheca

1913 Suctoria Mastigophora Mastigophora’ egg, attached pelagica sp.
Met”. sevickoteesevesh I Wetsassnenteese = 1,200

1/19 3,200 1,070,720

1/25 3,200 1,545,184

2/ 2 3,200 1,272,704

2/8 wae 24,000 4,161,840

2/15 AS cupbactaneede 43,200 3,709,024

2/23 Fecasseaspneetts 42,600 5,724,776

yf ercce alenaseadi 12,800 1,042,576

3/ 8 ‘en 36,800 504,768

SS Wasa: : 159,440 1,071,376

3 ace eE See 54,400 1,879,312

3/29 cackaneedaseuihe 19,200 1,316,752

4/5 deatsdeasezadys 124,992 290,080

4/13 137,792 544,864

4/19 219,584 462,416

4/26 464,016 1,039,624

5/ 3 Setevte suture 163,488 826,288

HOY Mee cesate ek 139,392 469,568

Gy (i Wy eee ee ceeeerrectire 273,232 442,424

SDA hed bien Vases 361,984 503,824

yale Mee tees sxencesceves 547,312 712,400

6/ 7 aries area nat 431,168 858,288

6/16 Mase : 320,576 488,016

Gy 2 Oe vive. chererates 573,008 946,480

GUOG, etna ree 881,536 ‘1,191,664

1920]

Allen: Plankton of the San Joaquin River

TABLE 3.—ORGANISMS PER Cusic METER IN PLANKTON OF
SmituH’s CANAL In 1913—(Continued)

Total
Suctoria

105,792
38,400
12,800

Total
Rhizota

Total Protozoa Total Protozoa

without

Mastigophora

955,328
1,569,432
1,229,408
1,715,072
2/596,608
1,509,888
5,504,384
1,665,376
3,292,352
5,036,224
1,387,096
2,433,216
1,464,896
5,209,408
3,144,768
1,599,680
1,577,384

726,048
1,314,404
1,480,992

112,000

148,040

135,344

62,496

138,640

75,296

Rotaria
neptunia

~ 3,200

wit
Mastigophora

2,293,728
3,506,536
3,785,920
6,768,992
5,222,016
5,597,184

14,496,704
6,329,824
7,761,216

11,922,112
6,904,696
6,254,522
6,671,504

11,066,380
6,644,704
4,456,064
3,507,240
4,765,344
6,398,820
4,803,592
9,163,520
4,094,344
2,849,040
2,935,264
2/459,040
2703,248

Rotaria
rotatoria

1,600
36,800
19,836
11,200
35,200
80,000
35,200

Collotheca

egg, attached

105,792
423/168
25,600
52,896

52,896
“6,400

Rotifer egg,
winter

Collotheca
pelagica

Total
Bdelloida

1,600
46,400
23,036
22,800
48,000
92,800
44,800
98,544
236,336
38,400
68,800
60,800
22,400
9,600
20,800
6,400

253

Collotheca
sp.

211,584
153,600

Anuraeopsis
egg, attached

254

1913
8/9
8/15
8/23
8/31
9/ 6
9/13
9/20
9/27
10/ 4
10/11
10/18
10/26
11/1
11/8
11/15
11/22
11/30
12/ 6
12/14
12/20
12/27

University of California Publications in Zoology

TABLE 3.—ORGANISMS Per Cusic METER IN PLANKTON OF
SmitvH’s CANAL IN 1913—(Continued)

Total
Rhizota

~ 102,400
89,600

576,768
$9,600
158,688
12,800
105,792
3,200
9,600

Anuraeopsis
fissa

Rotaria
neptunia

32,000

sp.

Rotaria
rotatoria

38,400

Asplanchna
brightiwellii

Rotifer egg,
winter

Brachionus

angularis

Total
Bdelloida

76,800
249,984
25,600
105,792
211,584
224/384
89,600
25,600
51,200
12,800
72,096
59,296
25,600

Brachionus
angularis
caudatus

740,544
317,376

[Von. 22

Anuraeopsis
egg, attached

Brachionus _
budapestenensis

1920]

Allen: Plankton of the San Joaquin River

TABLE 3.—ORGANISMS Per Cunic Mrter IN PLANKTON OF
SmituH’s Canau 1n 1913—(Continued)

Brachionus
Anuraeopsis Anuraeopsis Asplanchna Brachionus angularis
fissa sp. brightiwellii angularis caudatus
(VLIUTO Oils fa Pease eee IN 422,400
eee eet @ fre cb aRt 12,800 25,600
317,376 knee 12,800 Sasetesse ies 64,000
P2800) | eee eee Vee. Hivieseavestmers 38,400
Weseenicncay . ieecdocemeee Renna ane Pease 25,600
MOS 92) rece pier | aaets ddeaausss iEisesesusrcers 211,584
Jd A eR Rs gs ae er ae Ai teniersstiece 6,400
BAe peer) cakes. gee 19,200
GP400)" “eee SAS 6400" See
GOO eee) Vase: net
52,896 6,400 3,200
GOON eee eae :
Brachionus Brachionus Brachionus
Brachionus Brachionus egg; attached, egg; attached, egg; free,
calyciflorus capsuliflorus female male female
ees ; 3 SRP ON Pee erence Eee eee: 1,200
6,400 Bae eee Pee Os 3,200 1,600
3.200 ...... te 1,600 800 1,600
1,600 1,600 Si eee ONE ener Haga 3,200
38,400 ie ; 9,600 Pet: ; 3,200
USS SSO eee Patenevs 238,032 3,200 6,400
48,000 secee eee 28,800 seeds caeeweses 3,200
6,400 siete ‘ 9,600 eee Baie
38,400 cee as or 9,600 158,688
9600... Cre ae ON
41,600 6,400 22,400
6,400 eee : Ubud a eeseets
COMM en. eee.
3,200 Pasa | ae CEERE CE AOC sie eee
1,600 3,200 ees
6,400 3,200 SG0O =...
atid at 3,200
9,600 3,200 12/800 9,600
Scenes: 3,200 9,600 oe
ae ov 3/200
ae 3,200 | re
sees abe 12,800
ee : 6,400
3,200 ‘ 22 AO WG rte
seaasaeeasees : 12,800 6,400
; 52,896 79,344
1L9°200 ee. Se castes Reedcensaaues beSuseavedescess
6,400 Ee. ve 25,600 eee Pts 105,792
105,792 6,400 19,200 eae 12,800
6,400 317,376 32,000 44,800 ctheg eae
wa eees 3 3,200 eee sees tenaeseene 158,688
en Te 6,400... | EET 3,200
317,376 12,800 TADS) Secceneaceeece ‘ 317,376
Meoautes tae 12,800 2tSO0 Re ie Perce 105,792
ol 200 ee eta 64,000 Sik Acts eens 317,376
OTCOO I a eee ee, eee: ents Wit Mey ee
211,584 25,600 51,200 erate 12,800
211,584 25,600 317,376 see colsatae 211,584
ZO BROOD S yeesesecen: 256/000) eee 317,376

iw)
oO
on

Brachionus
budapestenensis

Brachionus
egg; free,
male

256

University of California Publications in Zoology

TABLE 3.—ORGANISMS PER Cusic METER IN PLANKTON OF
Smiru’s Canau In 1913—(Continued)

Brachionus
calyciflorus

12,800

Brachionus
patulus

Brachionus
capsulifilorus

Brachionus

egg; attached,

female

Brachionus
egg; attached,
male

Brachionus
plicatilis

Brachionus
urceus

Diurella
egg, free

370,272
~ 740,544
846,336
~ 528,960
105,792
528,960
634,752

Brachionus
egg; free,
female

6,400

Epiphanes
clavulata

“158,688
76,800
~ 128,000
76,800
12/800

“25,600

[ VoL, 22

Brachionus
egg; free,
male

Epiphanes
egg, attached,
female

1920]

Allen: Plankton of the San Joaquin River

TABLE 3.—ORGANISMS PER Cusic METER IN PLANKTON OF
Smitrn’s Cana In 1913—(Continued)

Brachionus
patulus

Brachionus
plicatilis

Filinia
egg, attached,
female

Filinia
egg, attached,
male

Brachionus
urceus

Filinia
egg, free

185,136
158,688

“211,584
211,584
~ 158,688
423,168
105,792

Diurella
egg, free

Filinia
longiseta

800

Epiphanes
clavulata

Keratella
cochlearis

4,800
6,400
3,200
35,200
60,800
79,344
80,000
317,376
634,752
476,064
238,032
264,480
502,512
264,480
423/168
83,200
79,344
25,600
687,648
105,792
32,000
105,792
264,480
449.616

3,173,760

257

Epiphanes
egg; attached,
female

Keratella
egg, attached

400
4,800
2/400
3,200
1,600
19,200
16,000

9,600
12,800

132,240

370,272

211,584
1,600

52,896

238,032

52,896

University of California Publications in Zoology [ Vou. 22

TABLE 3.—ORGANISMS PER Cusic METER IN PLANKTON OF
SmituH’s Canau 1n 1913—(Continued)

Keratella

egg, free
2,000
1,600
19,836
79,344
185,136
185,136
12,800

343,824
211,584
52,896
79,344
105,792
3,200
158,688
22/400
79,344

“317,376
3,200

158,688

“317,376
“317, 76

"211,584
264,480
423,168

Trichocerca
capucina

Keratella

quadrata
1,600
8,000
§,000
6,400
132,240
25,600
6,400
6,400
3,200

25,600
19,200
28,800
28,800
19,200

105,792
3,200
6,400
6,400

185,136
3,200

79,344
19,200
108,800
105,792
70,400
44,800
25,600
12,800
25,600
51,200

211,584

211,584

423,168

317,376

158,688

Trichocerca
lernis

Notholea
striata

Total

Ploima
6,800
36,800
71,272
108,144
481,520

Polyarthra
trigla

1,600
211,584
132,240

12,800

9,600

3,200

12,800
1,600
6,400
6,400

38,400

73,600

48,000

Total
Rotifera
8,400
83,200
94,308
130,944
529,520

Polyarthra
trigla ege; Synchaeta
attached, female sp.

he Le 423,168
Tico e: 211,584
264,480

ie aac 211,584
POOR. 370,272
keene 52,896
SR ie 105,792
3,200 105,792
3,20) 79,344
whee 238,032
ie 25,600
eee 185,136

Bosmina Chydorus
longirostris sp.

1920]

Allen: Plankton of the San Joaquin River

TasBLe 3.—OrGANISMS PER Cupic METER IN PLANKTON OF

Smituy’s Canau 1n‘1913—(Continued)

Trichocerca Trichocerca

capucina jernis

211,584
211,584
aie 38,400
Pee. 211,584
12,800 51,200
740,544
423,168
105,792
12,800
6,400

Sida Total
sp. Cladocera

Total
Ploima

841,344
324,800
200,944
737,424
696,304

1,693,792

1,025,728
466,368
441,520
958,336
432.576

1,011,136
179,200
506,080
204,144

2,377,584
179,392

$3,200
434,176

1,540,288

1,022,432

4,896,784
959,840
544,384

1,466,400

1,398,816
219,488

1,604,384

4,086,720

1,047,744

2)412,096
916,352

2,727,626

2/269,450

2,217,472

3,000,576

4,725,248

7,006,176

1,565,984
515,312

1,091,520
209,888
420,720
389,472

44,800
197,936

Canthocamptus

sp.

Total

Rotifera
934,144
369,600
299,488
976,960
734,704
1,762,592
1,086,528
488,768
451,120
979,136
438,976
1,015,936
180,800
538,080
210,544
2,545,872
188,992
83,200
440,576
1,540,288
1,134,624
5,002,576
963,040
703,072
1,644,288
1,475,616
219,488
1,899,178
4,125,120
1,153,536
2,726,080
1,230,336
2,817,226
2,625,226
2,845,440
3,102,976
4,956,032
7,078,272
1,697,376
534,512
1,110,720
216,288
423,920
392,672
44,800
197,936

Cyclops
sp.

Bosmina
longirostris

Nauplius
sp.

~ 1,600

bo
ON
ito}

Chydorus
sp.

Total
Copepoda

3,200
3,200
9,600
6,400
3,200
3,200

~ 3,200

University of California Publications in Zoology

TasLe 3.—OrGANISMS PER Cupic METER IN PLANKTON OF
Smiru’s Cana In 1913—(Continued)

Sida Total Cauthocamptus Cyclops Nauplius
sp. Cladocera Sp. sp. sp.
Sunsvossacsauny 3,200 Oy CL,
Ty 3,200
Pr A tes hts aa 8
ae 6,400 6,400

Total

Total
Malacostraca Entomostraca Glochidia

Macrobiotus Nematode

sp.

sp.

12,800

Total

Miscellaneous

[ Vou, 22

Total
Copepoda

Total

Organisms
1,008,388
10,034,524
6,611,056
9,370,608
18,043,608
11,550,608
17,982,424
23,079,776
12,047,088
14,866,400
19,465,312
26,761,792
6,492,272
11,646,736
13,637,936

1920]

Allen: Plankton of the San Joaquin River 261
TaBLeE 3.—OrGANISMS PER Cusic METER IN PLANKTON OF
Smitu’s Cana IN 1913—(Concluded)
Total otal Macrobiotus Nematode Total Total
Malacostraca Entomostraca Glochidia sp. sp. Miscellaneous Organisms
SESS: | CEDSCERTECACH EOP OSE ort ae 17,044,080
LAS OO Mee ee MN cer reset Santos 8,636,424
SS DOOG MMM tees. Tsien © Heed, 9,321,920
ORONO oo ngECOO RECON ben aoe ore EEE eee 9,352,280
UO SOOM fete cc Me Decteccc eae |) Stceeseecs 5,949,936
TO2O0 Metis. U reattacxcs’ | fesiscts 5,686,592
O° ZOOM, Pere een ee i Pee 10,101,808
DiGOONP eats — Seshis 15,708,784
eee 16,000 eee BES oo ee neste ees 19,352,112
See 12,800 Rens et Ue: ee sy Rei 26,840,944
6,400 Renee Gress Co artes “a secesceoners Call SLOG)
55,240 3,200 eho PE, 3,200 40,626,488
ea trereces 12,800 ee Gr so: ee See soceroececcs APIS eats}
57,600 6,400 a = e; 6,400 61,220,318
Ba A 38,400 Gee 6,400 Pee nos 6,400 66,621,792
Ree 76,800 6,400 Baten 5 Rees 6,400 114,201,816
32,000 Sete PAS ee ee 166,868,542
Ps eee 32,000 6,400 Sees as ; 6,400 141,852,410
Sheet hentee 90,600 ae cae Ge Pee cocomenican lay h ee Gey
51,200 254,328,524
G4:000" 5 2. 118,178,940
OE ZOOM Meters sn. pose 181,305,952
131,392 129,678,426
38,400 ae 109,717,814
ane 38,400 105,792 110,191,392
eee Penne | O97 81r440)
6,400 76,617,328
59 29CF we ce ae eee Pees. 46,179,728
ee, een me SN all ime tae 25,234,116
RN NR eee ee ew ee ccs 13,720,308
“ey teeceoys 9,600 is ate 17,451,856
cccSnidea! 0 MES Earon pO Te ePIC ES ream Erte 12,172,344
Reh 16,988,928
SOO RRM Se mE Mote e oe tees Sm deans. 10,538,544
BPA) aA gihektiaey PLES eee | 1 ieee hie Senet a 6,416,352
oe. Reece, Be Po eae ane 3,200 7,787,568

262 University of California Publications in Zoology [ Vou, 22

TABLE 4.—PLANKTON ORGANISMS Per Cuspic METER IN STOCKTON CHANNEL,
DatLy Series in 1913.

Spirillum Total Anabaena Aphanacapsa Gloeocapsa Gloeocapsa

1913 undula Bacteriaceae sp. sp. conglomerata sp.
7/5 105,792 105,792 retry ATGiOG4. © 2 ccticsisemns 264,480
a 6 Bticrsdores doers ven sebvensescdee eceeconecrece 952,128 © 4. avd 3,200
Cpt PEARS 528,960 bosoessteeretees 370,272
7/8 105,792 793,440 528,960 211,584
7/9 158,688 687,648 38,400 370,272
7/10 528,960 634,752 $46,336 158,688
7/11 amet hiss 528,960 634,752 740,544 476,064
7/12 2 era eesedtextaders 1,163,712 1,005,024 899,232 581,856
7/13 ae cae are 370,272 1,745,568 1,005,024 476,064
7/14 Paes dances Wy castaeeetsens 634,752 1,428,192 581,856 1,639,776
7/15 Uoesveastagedie ae 264,480 1,163,712 899,232 1,586,880
7/16 Bc eee BS Seo $46,336 1,216,608 158,688 1,375,296
7/17 dee se Sere 581,856 793,440 cSiaccuaeouneaes 740,544
7/18 3,200 3,200 3,200 211,584 211,584
7/19 3 ee) see juin 581,856 158,688 528,960
7/20 Series cee Pere Pu pert 12,800 3,200 476,064
7/21 Je baer Te a cians 3,200 105,792 264,480
LCP Ae weeeerrcen seh wets os coswames 211,584 Sy 200) eee tae 264,480
7/23 Petes iia Che cap deriatearess 105,792 G:400" eee ; ' 264,480
7/24 oe ate ra tree 6,400 3,200 3,200 158,688
7/25 3,200 3,200 ZT 584. ee Say 6,400 317,376
7/26 : eri Ayes yeaastees 211,584 264,480 ive : 1,005,024
7/27 ee ees Eo Shessiuies 158,688 264,480 211,584 1,057,920
7/28 ste base Sere : 211,584 1055792) anes bacssacce 634,752
7/29 , ais. eee 211,584 105,792 a eesgstasntatets 793,440
7H SOW ee ete 2 Aa (ig | ee a 158,688 211,584 3,200 317,376
7/31 : erect 6,400 ae : Saree 423,168
8/ 1 Seon kg RS wesc : 105,792 6:400F ee eee 317,376
8/ 2 3,200 3,200 ee ; 3i200) © xsixt: xs 105,792
Ve Shc a wrcc eeeey e Beee eee 211,584 12/300 ere 634,752
SUP Arne cee ne Ae 3,200 EMIS, concen ae 105,792

Gomphosphaera Merismopedium Microcystis Nostoc Oscillatoria Oscillatoria
1913 aponina glaucum sp. sp. sp. tenuis
Ghee 12,800 793,440 se hacteaweases 12,800
7/6 158,688 320,576 Sadesveutecgver | Pecpucespeneeee
UO. 3,200 743,744 scusseeveteen § Lunes ee
7/8 317,376 1,428,192 105,792 158,688
(Ge) 105,792 687,648 105,792 i... «
7/10 : 740,544 cath: : sar fs
7/11 211,584 ras ay - 211,584
7/12 264,480 476,064 3,200 370,272
7/13 264,480 373,472 476,064 3,200
7/14 : 264,480 793,440 105,792 370,272
7/15 3,200 : 370,272 1,057,920 370,272 3,200
7/16 317,376 793,440 211,584 a a
7/ : 1,375,296 317,376 1,110,816
uy, 264,480 423,168 370,272 sdeaupteeepee
u 264,480 740,544 370,272
T/: ; 3,200 214,784 211,584
7/3 3,200 2 211,584 317,376 1,269,504 ae :
T/: E 3,200 264,480 370,272 105,792
7/ 264,480 171,488 317,376 105,792
7 158,688 740,544 158,688 476,064
a. 3,200 , 3,200 528,960 370,272 370,272
THe : 264,480 528,960 476,064 ow... wed
T/% : 7 105,792 330,176 317,376 3,200
V/% 6,400 ee 317,376 746,336 528,960 105,792
7/ 3,200 105,792 581,856 158,688 476,064

1920]

Allen: Plankton of the San Joaquin River 263

TABLE 4.—PLANKTON ORGANISMS PER Cusic Meter IN STOCKTON CHANNEL,

Datzy Series In 1913—(Continued)

Gomphosphaera Merismopedium Microcystis
glaucum

aponina

Phormidium

spp.
“211,584
211,584
“370,272

Lagerheimia
wratislaviense

Rivularia
sp.

Pediastrum
boryanum

6,400
105,792

~ 105,792

12,800

sp.
211,584
317,376
264,480
105,792
3,200
3,200

Total
Schizophyceae
1,559,584
1,649,376
1,857,760
3,649,824
2,164,240
3,279,552
2,803,488
4,763,840
4,723,744
5,818,560
5,719,168
4,919,328
4,919,328
1,484,288

2,032,448
1,226,208

Pediastrum
duplex

476,064

793,440
1,110,816
1,269,504

899,232

793,440

740,544

793.440
1,005,024

634,752

740,544

Nostoe
sp.
323,776
267,680
264,480
3,200
581,856
264,480

Actinastrum
hantzschii

Pediastrum
simplex

3,200

12,800

Oscillatoria Oscillatoria

sp. tenuis
317,376 a a
740,544 317,376
317,376 158,688
476,064 3,200
370,272 211,584
476,064 211,584

Actinastrum
hantzschii Coelastrum
(large) microporum
6,400
105,792
158,688
264,480
158,688
3,200
meh = : 105,792
12,800 158,688
eas 423,168
3,200 211,584
6,400 158,688
105,792 105,792
211,584 158,688
19,200 3,200
19,200 105,792
6,400 105,792
105,792 105,792
105,792 “Ses ;
6,400 211,584
3,200 ee :
6,400 105,792
105,792 476,064
105,792 158,688
19,200 6,400
211,584 158,688
6,400 211,584
3,200 , A
12,800 264,480
6,400 105,792
19,200 211,584
3,200 211,584
Raphidium Raphidium
polymorphum pyrenogerum
ieeneeet 3,200
: : 105,792
264,480 370,272
105,792 3,200
ae : 158,688
3,200 en eiyee
3,200

264,480 :
211,584 158,688

105,792

~ 105,792 158,688

3,200

264 University of California Publications in Zoology [Vou 22

TABLE 4.—PLANKTON ORGANISMS Per Cusic METER IN STOCKTON CHANNEL,
Dainty Serres 1n 1913—(Continued)

Lagerheimia Pediastrum Pediastrum Pediastrum Raphidium Raphidium
wratislaviense boryanum duplex simplex polymorphum —pyrenogerum
tees: esi oe 211,584 6,400 isictsaeenes hetero
ae 12,800 211,584 3,200 siaidacdeaere 3,200
. : eee : 476,064 12,800 asa savas 158,688
6,400 634,752 158,688 3,200 3,200
105,792 528,960 105,792 F Mer 105,792
7 317,376 19,200 3,200 158,688
; : 6,400 793,440 19,200 3,200 264,480
3,200 : 793,440 6,400 3,200 105,792
: 634,752 25,600 6,400 Ree As
19,200 740,544 12,800 ; seaceegdaetetene
0 ; 740,544 3,200 decdsxsencteee 3,200
528,960 105,792 : 3,200
5 ; 423,168 6,400 105,792 158,688
3,200 476,064 6,400 ane 105,792
Sact Lee 634,752 12,800 158,688 370,272
6,400 T4054 Dg ciclo es | asarts errr 264,480
Scenedesmus Scenedesmus Schroederia Total Asterionella Amphiprora
1913 obliquus quadricauda setigera Chlorophyceae gracillima alata
Hae) 158,688 370,272 2 ere 1,021,024 a sfautvanavateye 3,200
7/ 6 3,200 687,648 1,649,376 : : Re es
i a 476,064 634,752 3,200 1,907,456 105,792 reir.
7/8 370,272 1,163,712 ws: ; 3,702,720 “Onb 3,200
7/9 211,584 634,752 BS gris 2,131,840 ‘ te ovistageree
7/10 370,272 1,057,920 = : 2,489,202 : ; 3,200
7/11 ; : 1,005,024 3,200 2,228,032 i waster nee
7/12 211,584 476,064 ¢ 2,138,232 — : 3,200
7/13 211,584 1,005,024 105,792 3,014,072 . a 3,200
7/14 528,960 1,057,920 Sore aes 2,971,776 speed : 3,200
7/15 264,480 264,480 158,688 1,699,072 3,200 ~ neces
7/16 423,168 1,375,296 4 ; 3,080,768 Bere neste soe eee
7/17 264,480 899,232 158,688 2,704,096 ebdete sess 3,200
7/18 317,376 423,168 264,480 1,668,576 svsicucistener’ || Lacneeeeeteere
7/19 528,960 952,128 : oe 2,462,624 4 ; 6,400
7/20 2,200 264,480 a ; 597,856 : : hae
7/21 158,688 158,688 158,688 819,040 o deteconnsaeeeee
7/22 476,064 423,168 3,200 1,655,776 : 3,200
7/23 105,792 581,856 105,792 1,817,664 ; : er on
7/24 317,376 793,440 3,200 1,963,552 Pere | lay ran picc
7/25 211,584 899,232 158,688 1,880,160
7/26 687,648 1,005,024 105,792 3,470,240
7/27 740,544 1,692,672 105,792 3,715,520
7/28 370,272 1,481,088 3,200 2,550,102
7/29 476,064 687,648 mee ; 2,306,528
7/30 317,376 634,752 3,200 1,919,256
7/31 3,200 581,856 3,200 1,229,408
8/1 634,752 1,005,024 3,200 2,617,504
8/ 2 105,792 899,232 3,200 1,710,872
8/ 3 264,480 423,168 Sop Sieae 2,101,344 cent
8/ 4 264,480 846,336 FTO RaS PABRY AUS | ea
Bacillaria Cyclotella Cyclotella Cymbella Cymbella Cymbella
1913 paradoxa kutzingii operculata affinis ceymbiformis tumida
7/5 ; 370,272 ).13, 01649 | eee eee
7/6 SEO 740,544 8,780,736 pocntatcseuckavt ee) Ghtaseteaiets
ed ‘ ie 211,584 11,901,600 : ; eer
Hi eS Seasenstasaree 1,005,024 12,906,624
7/9 sates 264,480 12,060,288 wheats Scehisesantasues
7/10 Zeke ache 581,856 13,858,752 Pee oro are F

-1920]

Allen: Plankton of the San Joaquin River

TaBLE 4.—PLANKTON ORGANISMS PER Cusic METER IN STOCKTON CHANNEL,

Bacillaria
paradoxa

Epithemia

ocellata

6,400

Daly SERIES IN 1913—(Continued)

Cyclotella
kitzingii
370,272
211,584
476,064
846,336
634.752
423,168
528,960
317,376
264,480
105,792
105,792
105,792
158,688
105,792
211,584
581,856
793,440
952,128
317,376
952,128
740,544
1,163,712
1,692,672
1,692,672
1,269,504

Gyrosigma
kiitzingii

Cyclotella

operculata
13,118,208
16,556,448
26,448,000
37,291,680
36,022,176
45,331,872
46,178,208
31,949,184
24014,784
14,070,336
16,133,280
18,672,288
11,584,224
13,647,168
13,964,544
16,768,032
18,143,328
16,820,928
16,397,760
14,916,672
17,032,512
16,186,176
13,224,000
12,271,872
10,579,200

Gyrosigma
scalproides

Cymbella
affinis

Melosira
granulata

1,005,024
1,745,568
1,110,816
1,481,088
1,481,088
1,798,464
2,433,216
2,697,696
1,269,504
1,533,984
1,216,608
1,586,880
2/486, 112
1,957,152
2,168,736

476,064
1,163,712
2,221,632
1,428,192
3,226,656
1,163,712
2,962,176
2,327,424
3,279,552
2'010,048
2/539,008
1,904,256
1,163,712
3,914,304
4,707,744
3,544,032

26

Cymbella Cymbella
eymbiformis tumida

3,200

6,400

A aie 3,200
6,400 miss
3200 § elcome

ane 6,400
Melosira Navicula
varians alpestris
“3,200 ne

dees 3,200
SAU 0 eek Ga
eeoerencn 105,792
3,200 eee

400

6,400

6,400

i) |

266

University of California Publications in Zoology

[Vou. 22

TaBLe 4.—PLANKTON ORGANISMS PER Cusic METER IN STOCKTON CHANNEL,

Navicula
bacillum

~~ 3.200

~ 105,792

105,792
3,200
3,200
3,200

Surirella
sp.

Datty Serres In 1913—(Continued)

Navicula
gracilis

3,200
~ 105,792
3,200

158,688
3,200

158,688
264.480
105,792
370,272
370,272
211,584

3,200

3,200
158,688

3,200
105,792
105,792
423,168
476,064
370,272
317,376
370,272
264,480
211,584
264,480

3,200
317,376

Synedra
radians

3,200
3,200
19.200
6,400

12,800
3,200
12,800
3,200
12800
6,400
105,792
12,800
6,400
12,800

5,501,184
5,765,664
4,284,576
4,496, 160
3,279,552
1,322,400
634,752
528,960
528,960
793,440
581,856
370,272
476,064
899,232
687,648
476,064
1,005,024

Nitzschia
acicularis

4,284,576
2°750,592
4,337,472
3,967,200
2,909,280
4,760,640
5,448,288
4,866,432
6,083,040
5,130,912
4,496,160
5,025,120
5,183,808
3,914,304
4,125,888
2,062,944
2,697,696
2'697,696
2,380,320
2,909,280
4,231,680
6,982,272
9,309,696
7,088,064
6,030,144
3,755,616
4'813,536
3,544,032
3,385,344
3,226,656
3,702,720

Synedra
ulna

423,168
370,272
952,128
899,232
476,064
581,856
370,272
423/168
740,544
637,952
846,336
634,752
1,110,816
317,376
317,376
264,480
476,064
370,272
528,960
476,064
211,584
687,648
793,440
899,232
899,232

Nitzschia
sigma

~~ 3.200

~ 3,200
3,200

“112,192

Total
Bacillariaceae
20,001,088
14,397,312
18,619,392
20,374,560
17,204,000
21,749,856
21,743,456
24,761,728
40,709,024
51,741,888
47,625,600
58,002,816
59,463,008
39,790,592
31,801,600
17,543,776
21,127,904
25,045,408
16,675,040
20,863,424
20,387,360
29 637,760
32,809,824
29,918,240
27/263,840

Nitzschia
vernucularis

Pleurostauron
parvulum

Closterium
rostratum

sp.

3,200
3,200

3,200
3.200

1920]

Allen: Plankton of the San Joaquin River

267

TaBLE 4.—PLANKTON ORGANISMS PER Cupic METER IN STOCKTON CHANNEL,

Surirella

Staurastrum
A

3,200

Chilomonas
sp.

Dairy SeErt&s 1n 1913—(Continued)

Synedra
radians

423,168
476,064
. 846,336
370,272
370,272
793,440

Staurastrum
sp.

Chlamydomonas

~ 105,792
05,792

Synedra
ulna

528,960
370,272
423,168
423,168
634,752
211,584

Total
Conjugatae

Chromulina
sp.
634,752
1,428,192
2,221,632
3,385,344
2,486,112
3,596,928
3,120,864
4,919,328
6,664,896
7,088,064
6,188,932
5,183,808
4,866,432
4,760,640
6,929,376

Total

Bacillariaceae

23,495,424
25,745,856
23,766,304
23,354,240
22'967,968
20,630,944

Total
Chlorophyll
bearing

24,657,440
20,518,752
25,811,552
31,487,424
24,516,656
31,763,090
30,378,304
37,862,232
56,860,504
68,840,096
62,240,896
71,364,608
72,392,032
48,292,352
43,953,794
22/560,800
27,722,208
30,423,104
23,044,054
27,956, 192
27'893,696
44,063,882
45,490,368
42/223 606
39,375,328
31,213,344
33,447,776
34,225,216
30,601,496
32,774,482
31,681,322

Eudorina
elegans

6,400
6,400
57,600
19,200
3,200
3,200
6,400

~ 158,688

Closterium
rostratum

3,200
6,400
3,200

~ 3,200

Total
Algae
22,693,888
17,699,264
22,384,608
27,727,104
21,506,480
27,521,810
26,778,176
31,667,000
48,450,040
60,852,800
55,047,040
66,012,512
67,089,632
42,953,056
36,912,226
19,069,664
24,227,872
27/930,592
19,758,112
24,538,848
24'190,976
35,865,002
39,133,248
35,234,934
32,019,584
26,967,864
29,057,408
27'821600
25,771,960
27,104,960
24,312,778

Euglena

viridis
3,200
3,200
105,792
211,584
3,200
105,792
793,440
1,057,920
370,272
634,752
158,688
423,168
476,064
6,400

Mougeotia
sp.

Cercomonas
crassicauda

Hemidinium
nasutum

pe

ii ee a ee)
SOMNIAEA &

Ns 2

—

University of California Publications in Zoology [ Von, 22

TABLE 4.—PLANKTON ORGANISMS Per Cunic Meter in StocKTON CHANNEL,
Dality Series 1n 1913—(Continued)

Chilomonas Chlamydomonas Chromulina Eudorina Buglena Hemidinium
sp. sp. sp. elegans viridis nasutum

3,015,072 476,064
2'856,384 634,752 -
2,274,528 211,584
3,173,760 105,792
2,750,592 476,064
2'803/488 423'168
7,299,648 370,272
5,395,392 634,752
6,347,520 4231684 =. . ae
ne a IN 4,496,160 423.168 2,327,424
eo | UO EeCTE 3,279,552 423,168 528,960
spedesthasteites 3,385,344 158,688 $46,336
3,200 3,649,824 264,480 2,486,112
ROEM ap etes OR 3,967,200 105,792 634,752
P20 ee terercs we 4,919,328 3,200 634,752
eee secapett 3,200 5,130,912 12,800 1,639,776
Mallomonas Peridinium Pleodorina Pteromonas Synura Trachelomona
sp. cinctum californica sp. uvella euchlora
3 200° 1005024 44.0. T5SI6BS © ices ne on

PRN ct 581,856 6,400 211,584 158,688
es cose GOVE: Gy eager eee meee:

As merece we Tae) 7700

SREP tie a “ocean eee 211,584
Trachelomonas Total Amoeba Difflugia Microgromia Total

volyocina Mastigophora radiosa pyriformis socialis Rhizopoda
264,480 2,069,344 —_....... ae ZU Sa ac ciekactee ‘ 224,384
317,376 2,819,488 3,200 476,064 Seeuetetanete 479,264
528,960 3,426,944 Voie eas 264,480 3,200 267,680
211,584 3,760,320 3,200 12,800 geackys Cpe ganewe 19,200
264,480 3,016,576 decgankeeeens 264,480) cicitvestians 270,880

528,960 4.241.280 veces S200 ee eee 3,200

1920]

Allen: Plankton of the San Joaquin Riwer

TasLe 4.—PLANKTON ORGANISMS Per Cusic METER IN STOCKTON CHANNEL,

Trachelomonas
volvocina

370,272
476,064
687,648
105,792

105,792
370,272

Heterophrys
fockei

528,960
317,376

Daity SERIES IN 1913—(Continued)

Total
Mastigophora
3,600,128
6,195,232
8,410,464
7,987,296
7,193,856
5,352,096
5,302,400

8,198,880
6,357,120
6,988,672
7,355,744
4,244 480
4,390,368
6,403,616
4,832,736
5,669,472
7,368,544

Raphidiophrys
elegans
528,960
740,544
846,336

1,110,816
846,336
370,272
423/168
158,688

1,110,816

1,005,024
370,272
528,960
158,688
211,584
370,272
105,792
264,480
317,376
317,376
317,376
105,792
370,272
476,064
423,168
528,960
370,272
476,064
687,648

1,269,504
740,544
952,128

Difflugia
pyriformis

Amoeba
radiosa

6,400
6,400
3,200
d scusdetosttas 105,792
6,400
105,792
ei 158,688
Boa areas 264,480
211,584
6,400
105,792
3,200
Total Holophrya
Heliozoa sp.
528,960 158,688
740,544 105,792
846,336 158,688
1,110,816 105,792
846,336 211,584
370,272 211,584
423,168 423,168
158,688 3,200
1,110,816 211,584
1,005,024 105,792
370,272 528,960
528,960 6,400
158,688 ..... ue
211,584
370,272 mat
112,192 3,200
310,272 264,480
317,376 3,200
CHIT SAG) | catecoes '
317,376 3,200
105,792 264/480
370,272 211,584
476,064 317,376
528,960 158,688
528,960 158,688
415,072 105,792
581,856 105,792
694,048 264,480
1,798,464 105,792
1,269,504 3,200
1,269,504 158,688

Total

Microgromia I
i Rhizopoda

socialis

9,600
6,400
108,992
6,400

105,792
370,272
158,688

~ 105,792
105,792

~ 158,688
105,792

Prorodon Tintinnidium
sp. fluviatile

en 1054702
3,200 105,792
Suse 3,200
sly a ~ 6,400
6,400

=

ee

aa r
WHE OOMNIOQU Y

INNIS

=
_
w

University of California Publications in Zoology

(Vou. 22

TABLE 4.—PLANKTON ORGANISMS PER Cusic METER IN STOCKTON CHANNEL,

Vorticella
B
3,200

~ 158,688

211,584
370,272
634,752
105,792
158,688
~ 105,792
3,200

Rotaria
neptunia

~ 6,400
12,800

3,200

~ 6,400

~~ 19,200

Dainty Series in 1913—(Continued)

Vorticella
longifilum

Rotaria
rotatona

19,200
25,600
6,400
12,800
6,400
25,600
3,200
211,584
38,400
264,480
6,400
19,200
317,376
6,400

~ 6,400
19,200

Vorticella
sp.
2,644,800
1,375,296
1,057,920
1,110,816

476,064
1,322,400
846,336
740,544
634,752
1,163,712
846,336
1,110,816
1,163,712
370,272
1,057,920
476,064
370,272
1,005,024
476,064
899,232
793,440
1,269,504
1,957,152
1,586 880
2,010,048
899,232
1,533,984
1,269,504
1,639,776
1,957,152
1,692,672

Rotifer
unidentified
158,688
211,584
3,200
6,400
3.200

3,200
158,688
158,688

3,200

19,200
264/480

3.200
158,688

3,200

3,200

3,200
105,792
25,600
105,792
211,584
105,792

Total
Ciliata
2,806,688
1,490,688
1,216,608
1,216,608

687,648
1,533,984
1,269,504

743,744

846,336
1,269,504
1,375,296
1,116,216
1,163,712

370,272
1,057,920

476,064

1,966,752
1,860,950

Total
Bdelloida

177,888
237,184
16,000
19,200
9,600
25,600
16,000
214,784
196,088
426,368
9,600
38,400
581,856
9.600
158,688
9,600
19,200
22,400
317,376
115,392
112,192
38,400
131,392
211,584
105,792

Total, Protozoa Total, Protozoa

without
Mastigophora

3,560,032
2,707,496
2,330,624
2,346,624
1,804,864
1,907,456
1,692,672

905,632
1,960,352
2/280,928
1,748,768
1,757,368
1,335,200

591,456
1,434,592

697,448

951,424
1,325,600

899,232
1,593,280
1,428,192
2,125,440
2,968,576
2,287,328
2,912,480
1,535,488
2,337,024
2,231,232
3,547,232
4.394.944
4,236,246

Anuraeopsis
fissa

wi
Mastigophora
5,629,376
5,526,984
5,757,568
6,106,944
4,821,440
6,148,736
5,292,800
7,100,864
10,370,816
10,268,224
8,942,624
7,109,464
6,637,600
5,933,952
8,476,160
4,188,584
4,445,760
3,818,112
4,185,184
5,010,624
5,184,112
10,324,320
9.325.696
9,276,000
10,268,224

Asplanchua
brightwelli
158,688
57,600
70,400
19,200
19,200
89,600
51,200
44,800
76,800
158,688
64,000
12/800
19,200
105,792
6,400
12,800
19,200
25,600
3,200
12,800

19,200
38,400
12,800
32,000

1920]

Allen: Plankton of the San Joaquin River

271

TaBLE 4.—PLANKTON ORGANISMS Per Cusic METER IN STOCKTON CHANNEL,

Rotaria

neptunia
6,400
6,400

Brachionus
angularis

3,200
3,200

3,200

158,688

Brachionus

egg; attached,

male

~ 105,792

Datuy SERIEs IN 1913—(Continued)

Rotaria
rotatoria

6,400
12/800
3,200
32,000
158,688
6,400

Brachionus
angularis
caudatus

476,064
423.168
264,480

1,269,504

1,163,712
581,856

1,005,024

1,375,296
581,856
846,336
740,544
793,440

1,057,920

1,110,816
793,440
476,064
370,272
528,960
317,376
740,544

1,216,608

1,481,088

3,755,616

1,851,360
581,856
423168
264,480
581,856
211,584
211,584
264,480

Brachionus
egg; free,
female

1,005,024
581,856
793,440

1,057,920
899,232

1,269,504
846,336

1,005,024
740,544
528,960
687,648
370,272
476,064

1,005,024

Rotifer Total

unidentified Bdelloida
3,200 16,000
Syevideteenec tie 19,200
158,688 161,888
3,200 41,600
3,200 174,688
105,792 112/192
Brachionus Brachionus

budapestenensis calyciflorus

Brachionus Brachionus
patulus plicatilis

6,400

Anuraeopsis
fissa

Brachionus
capsuliflorus

Brachionus
urceus

44,800
6,400
12,800
19,200
44.800
211,584
158,688
528,960
370,272
581,856
528,960
528,960
47,064
1,216,608

Asplanchua
brightwelli

12,800

Brachionus egg;
attached,
female

158,688

317,376
687,648
423,168
846,336
264,480
370,272
476,064
158,688
211,584
581,856
158,688
476,064
846,336
370,272
1,428,192
634,752
211,584
12,800
211,584
370,272
264,480
105,792
158,688

Diurella
44

bo
~]
bo

1913
7/19
7/20
7/21

NNN
ee a ae ie

13

University of California Publications in Zoology

[ Vou. 22

TABLE 4.—PLANKTON ORGANISMS Per Cupic METER IN STOCKTON CHANNEL,

Brachionus
egg; attached,
male

Filinia

3,200

Keratella
egg, free

476,064
264,480
105,792
158,688
211,584

Daly Series 1n 1913—(Continued)

Brachionus
egg; free,
female

264,480
423/168
846,336

1,057,920
740,544
528,960

1,057,920
476,064

1,851,360

158,688
317,376

Filinia egg;
attached,
female

158,688

Keratella
quadrata

1,163,712
317,376
317,376
687,648
264,480

Brachionus
patulus

Brachionus
plicatilis

Filinia
egg, free
370,272
528,960
317,376
528,960
476,064
476,064
423,168
370,272

3/200
105,792
158,688
105,792
211,584
105,792
105,792

3,200
105,792
105,792
158,688
211,584
211,584
105,792
158,688
105,792
158,688
158,688

211,584
158,688

Polyarthra
trigla

158,688
211,584
528,960
740,544
899, 232

Filinia
longiseta

1,875,296
370,272
317,376
264,480
12,800
44,800
158,688
105,792
158,688
211,584

Polyarthra
trigla egg,
attached

Brachionus
urceus

370,272
740,544
634,752
634,752

6,400
211,584
370,272
423.168
528,960
528,960
370,272
105,792
158,688
423,168
370,272
423.168
317,376

Keratella
cochlearis

793,440
211,584
476,064
211,584
211,584
423,168
581,856
423,168
476,064
476,064
158,688
12,800
32,000
25,600
32,000
158,688
158,688
105,792
38,400
19,200
12/800
6,400

Synchaeta

sp.
528,960

Diurella
egg

Keratella egg,
attached

211,584

Trichocerca
capucina

1920]

Allen: Plankton of the San Joaquin River

273

TasBLe 4.—PLANKTON ORGANISMS PER Cusic Meter in Stockton CHANNEL,

Keratella
egg, free

317,376
370,272

211,584
105,792
105,792
105,792
158,688

211,584

~ 105,792
3,200

158,688
3,200
3,200
3,200

105,792

~ 105,792

Trichocerca
iernis

19,200

19,200
158,688
317,376
211,584
370,272
476,064
317,376
264,480
105,792

6,400
3,200
6,400
6,400
12,800
158,688
6,400
158,688
12,800
3,200
6,400
6,400
19,200
25,600
25,600
19,200
12,800
6,400

Dainty SpERIgs IN 1913—(Continued)

Keratella
quadrata

528,960

687,648
1,322,400
1,110,816
1,057,920
1,110,816

952,128

687,648
1,322,400

846,336
1,057,920

846,336
1,110,816
1,692,672
1,163,712
2,010,048
2,062,944
5,554,080
2,644,800
4,601,952
2,010,048
2,856,384
2,909,280
1,110,816

423,168
1,057,920

Total
Ploima
7,111,968
3,229,664
3,590,336
5,921,656
5,127,720
6,445,024
6,884,384
8,578,056
6,113,344
5,940,352
4,252,384
4,348,576
3,419,552
5,557,088
3,390,048
3,373,856
3,588,832
4,966,136
3,428,256
3,010,176
6,069,000
5,972,352

15,098,656
7,241,956
8,434,368
4,255,784
5,384,096
5,816,864
3,639,032
1,958,656
2/859,088

Polyarthra
trigla
1,745,568
1,798,464
1,692,672
1,904,256
1,163,712

370,272
687,648

38,400
76,800
158,688
89,600
158,688
101,400
134,400
211,584
476,064
634,752
1,216,608
581,856
846,336
952,128
846,336
793,440
793,440
264,480
264'480

Total
Rotifera
7,289,956
3,466,848
3,606,336
5,940,856
5,137,320
6,470,624
6,900,384
8,792,840
6,309,432
6,367,720
4,261,984
4,386,976
4,001,408
5,566,688
3,548,736
3,383,456
3,608,032
4,988,536
3,745,632
3,125,568
6,181,192
6,010,752

15,230,048
7,453,440
8,540,160
4'271,784
5,403,296
5,978,752
3,680,632
2,133,344
2:971,280

Polyarthra
trigla egg,
attached

~~ 3,200

Bosmina
longirostris

Synchaeta
sp.

~ 3,200

Trichocerca
capucina

Total
Cladocera
6,400
32,000
6,400

6,400
12,800
6,400
12/800

6,400

12,800
12,800
12,800
12,800

"25,600

bo
~
TS

1913
qWa5
7/6
WEG
7/8
7/9
7/10
7/11
7/12
7/13
7/14
7/15

University of California Publications in Zoology

Cyclops
268,800
332,800
317,376
317,376
370,272
230,400
358,400
740,544
268,800
687,648
476,064
454,400
264,480
581,856
687,648
581,856
581,856

3,173,760

264,480
264,480
423168
264,480
476,064
528,960
634,752
317,376
423,168
846,336
581,856
264,480
317,376

Nauplius
1,057,920
634,752
528,960
793,440
1,163,712
793,440
740,544
856,336
1,375,296
1,428,192
1,057,920
793,440
740,544
581,856
740,544
899,232
1,745,568

- 1,692,672

1,110,816
$99,232
952,128
687,648
952,128
793,440

1,269,504
740,544
581,856
899,232

1,322,400
846,336

1,163,712

Total
Copepoda
1,326,720

967,552

846,336
1,110,816
1,533,984
1,023,840
1,098,944
1,586,880
1,644,096
115,840
933,984
247,840
005,024
163,712
428,192
481,088
327,424
866,482
375,296
170,112
375,296
9
4
3
9
0
0
Meh
9
1
4

,
)
)

2}
1
is
1
1
1
i.
2,
4,
ls
1,
ie
52,128
28,192
22,400
(04,256
57,920
105,024
45,568
904,256
110,816
481,088

’
)
’
)

1
1
1
1
il}
1
1
1
1

Total
Entomostraca
1,333,120

999,552

852,736
1,110,816
1,533,984
1,030,240
1,111,744
1,593,280
1,656,896
2°115,840
1,540,384
1,247/840
1,017,824
1,176,512
1,440,992
1,493,888
2)327,424
4,892,032
1,375,296
1,182,912
1,381,696

958,528
1,434,592
1,322,400
1,904,256
1,064,320

Glochidia

~ 3,200
3,200
6,400

[ VoL, 22

TABLE 4.—PLANKTON ORGANISMS PER Cupic METER IN STOCKTON CHANNEL,
Datny Serres 1n 1913—(Concluded)

Total

Organisms
36,946,240
27,692,648
32,601,248
40,885,720
32,992,824
41,171,410
40,083,104
49,153,984
66,787,184
79,604,584
69,792,032
78,756,792
78,746,464
55,630,208
50,284,514
28,135,592
34,609,088
41,632,472
29,064,214
33,857,952
36,887,976
53,158,602
65, 1 23, 584

38,088,136
42'199,520
44,180,768
39,749,616
40,419,936
40,376,336

1920]

Allen: Plankton of the San Joaquin River

bo
~
On

TaBLEe 5.—PLANKTON ORGANISMS PER Cusic Meter IN SmitH’s CANAL,
Hourty Serres 1n 1913

1913 Lamprocystis
8/1l sp.
10) OMe me esc cece =
OU AGNCCn mee
NAG aie es: 2osccc.305

ol AGING eeeeteste nes see

ILE ANS es) accemnee

12 m. scpSteceeeene
UMP EN Tey trees Sect. oS:
2 PAN MEN faeces cB
Shine sarees
4 P.M. 52,896
5 P.M. 52,896
5:48 P.M. .... :
6:40 P.M. 6,400
1913 Gloecocapsa
8/11 sp.

7 A.M. 343,824
8 A.M. 343,824
9 a.M. 264,480

10 a.m. 343,824

11 a.m. 343,824

12 m. 158,688
1 P.M. 766,992
2 P.M. 661,200
3 P.M. 608,304
4 P.M. 608,304
5 P.M. 925,680
5:48 p.m. 714,096
6:40 p.m. 925,680
1913 Phormidium
8/11 foveolarum
7 AM. 211,584
8 A.M. 158,688
9 A.M. 158,688

LQUAG. A), Pepeeeeee eee

11 a.m. 52,896

12 Mm. 264,480
1 P.M. 264,480
2 P.M. 343,824
3 P.M. 211,584
4 P.M. 264,480
5 P.M. 264,480
5:48 P.M. .... ;
(3)322 40) 32 ig peneerreer ee
1913 Pediastrum
8/11 boryanum
EINES ae eee
8 a.m. 12,800
9 a.m. 5

10 a.m.

11 a.m.

12 mM. 12,800
1 P.M. 52,896
2 P.M. 19,200
3 P.M. 12,800
4 P.M. 105,792
5 pM. 158,688
5:48 p.m. 105,792
6:40 p.m. 6,400

Total Anabaena
Bacteriaceae sp.
erat 105,792
343,824
52,896
396,720
449,616
449,616
502,512
1,163,712
: 1,719,120
52,896 1,666,224
52,896 3,861,408
3,967,200
6,400 5,236,704
Gomphosphaera Microcystis
aponina sp.
52,896 211,584
F 343,824
449,616
158,688
105,792
158,688 661,200
264,480
158,688 343,824
343,824
396,720
502.512
nee 502,512
105,792 449,616
Stigonema Total
ocellatum Schizophyceae
: 1,454,644
52,896 1,461,040
984,976
1,454,640
1,533,984
52,896 2,545,408
2,115,840
5,871,456
8,096,640
8,701,394
6,400 = 10,083,088
52,896 8,542,704
12,040,250
Pediastrum Pediastrum
duplex simplex
449,616 6,400
766,992 52,896
396,720
449,616 105,792
661,200 158,688
608,304 52,896
1,216,608 6,400
1,163,712 52,896
1,110,816 105,792
925,480 52.896
1,533,984 12,800
1.481,088 25,600
1 216,608 6,400

Aphanocapsa Coelosphaerium

sp.
264,480
158,688
6,400
52,896
211,584
343,824
158,688
105,792
502,512
211,584
158,688
105,792
158,688

Nostoe
sp.
211,584
52,896,
52,896
396,720
105,792
459,616
52,896
3,120,864
4,522,608
5,448,288
3,914,304
2697696
3,306,000

Actinastrum
hantaschii

52,896

52,896
6,400

Raphidium

polymorphum

105,792
52,896
6,400

52,896

kitzingianum

52,896

Oscillatoria
sp.

~ 158,688

449,616
502,512
264,480

Actinastrum
hantzschii
(large)

105,792
158,688
264,480
343,824
502,512
211,584
449,616
343,824
661,200
264,480
396,720
502,512
608,304

Raphidium
pyrenogerum

52,896

105,792

Gloeocapsa
conglomerata

52,896
6,400

105,792
52,896
6,400
105,792
52,896
52,896

Oscillatoria
tenuis

105,792
52,896

Coelastrum
microporum

105,792
105,792
105,792
52,896
105,792
158,688
52,896
6,400
19,200
158,688
52,896
211,584
264,480
Scenedesmus
obliquus
52,896
264,480
52,896
211,584
52,896

52,896
343,824
343,824
211.584
264,480
158,688
158,688

276 University of California Publications in Zoology [ VoL, 22

TasLe 5.—PLANKTON ORGANISMS Per Cunic Merer IN Smitu’s CANAL,
Hourty Serres 1n 1913—(Continued)

1913 Scenedesmus Schroederia Total Asterionella Amphiprora Bacillaria
8/11 quadricauda setigera Chlorophyceae gracillima alata paradoxa
7AM. 158,688 673,392 52,896 158,688 264,480
8 A.M. 264,480 T4G7 440) © ccscsssscchasars 264,480 211,584
9 A.M. 105,792 661,200 52,896 502,512 158,688
10 A.M. 211,584 WOSUM412. cavcoseseens 502,512 211,584
lla. 264/480 1,205,952 eecscsccose 502,512 60,800
12 M. 158,688 GOT TOI ® Coastemcee nares 211,584 343,824
lpm. 264,480 1751-068 9 ae 343,824 211,584
2 P.M. 449,616 ZAGA S36 ekeasveatiere 211,584 396,720
3 P.M. 449,616 247,840 | wes: ‘ats 211,584 449,616
4 P.M. 396,720 1,910,656 105,792 343,824
5 P.M. 555,408 2,578,256 52,896 158,688
5:48 p.m. 588,408 2,696,848 158,688 343,824
6:40 p.m. 925,680 — ................ 2,743,334 264,480 158,688
1913 Cyclotella Cyclotella Cymbella Cymbella Cymbella Epithemia
9/11 kiitzingii operculata affinis cymbiformis tumida ocellata
Team, WITAZR1G2” —GiSOS Gye Tals tnt eee Se ee oe 52,896
Sam. 1,005,024 4,312,024 coves. 6,400 52,896

9am. 1,322,400 4,178,784 Nias OTe Re eae : :
LOA: . LOGG204 5 AGAGRS Gh cen dae ate eae mae
11 AM. 1,269,504 2,750,592 oosssscssce BOGGG: lee one tee
12 mM. 819,888 2,697,696 52,896 sacheoccosearace ae

lpm. 1,719,120 3,623,376 take cae septecvesscvenss ERE AE

2pm. 1,983,600 4,178,784 BO ROG) Me ae 6,400

3Pp.M. 2,195,184 2,856,384 525896) SC leccmeteriets uy agesevteseeseese

4pm. 2,036,496 3,702,720

5 p.m. 2,539,008 4,072,992 12,800
5:48 p.m. 1,877,808 CUNY PAS iam” Rreeeeo | tepretereceag o.antean wees
G40 pm 1 ADR 192 <0 305 902s oe co eee ee
1913 Fragillaria Gomphonema Gyrosigma Gyrosigma Gyrosigma Melosira
8/11 capucina constrictum acuminatum kiitzingii scalproides granulata
7 AM. 6,400 52,896 158,688 10,790,784
8 A.M. 52,896 343,824 10,526,304
9 A.M. 158,688 8,486,912
10 A.M. 343,824 8,198,880
11 A.M. Re. cee ee ae reece oe : 158,688 8,489,808
1 Pa Serer wees OZB9G | cssd.ccccgiven |) gecosersrcersees 52,896 9,568,384
GR EME DL Sais toserecseeers siesta 211,584 343,824 12,668,592
2 P.M. 52,896 Rr oe 105,792 449,616 19,883,104
3 P.M. 6,400 52,896 158,688 819,888 20,655,888
ASPUM SS hiecesscoreners x: . 6,400 766,992 24,067,680
OUP Mee | hessaeseeseeee 52,896 396,720 925,680 34,990,704
5:48 p.m. 52,896 52,896 52,896 1,057,920 31,737,600
GEO Pints ei. sesssetecead Pecceeee eae ies acesetnsrecNert 105,792 661,200 35,863,488
1913 Melosira Navicula Navicula Navicula Navicula Navicula
8/11 varians alpestris bacillum didyma dubia gracilis
TR Pa ee ee RS ae 158,688 oy pee ots 1,269,504
SUA Wonks deecsaxaness 6,400 WODI7T92) 9 © cece sevieescce tote 1,163,712
QUANT eb citiac Sotecss oe Beceec sceer ee saperecsceetes Prices saat 766,992
10 A.M. 52,896 105,792 158,688 52,896 1,005,024
11 A.M. 52,896 12,800 itr ere 1,163,712
1 AR err ore 52,896 fees ; 819,888
ASP EMM 8 9 Se nccsac tee 12,800 105,792 872,784
QNBIMGH (i cciavtaes cates earn 105,792 1,163,712
3 P.M. 6,400 52,896 Aicscceeeey 2 Se Gascareeee 872,784
A PUM Om ceav.3 , 158,688 52,896 1,269,504
5 P.M. 6,400 105,792 Sevan eee asks cyseeneee 1,586,880
BAS IPMS scssenstesterere 158,688 LOD 792) “hvac 1,216,608
GA 0IPIMG 6s. stciereenre 52,896 52896) 9 csicsasnntcce 2,142,288

Allen: Plankton of the San Joaquin River

TABLE 5.—PLANKTON ORGANISMS PER Cusic Mrrer in Smitu’s CANAL,
Hour.y Series 1n 1913—(Continued)

1920]
1913 Navicula
8/11 viridis
7 AM.
8 A.M.
9 A.M.
10 a.m.
11 a.m.
12 M.
1 P.M.
2 P.M.
3 P.M.
4 P.M.
5 P.M.
5:48 P.M.
6:40 p.m. 6,400
1913 Surirella
8/11 sp.
7 A.M. 158,688
8 A.M. 343,824
9 A.M. 211,584
10 a.m. 60,800
11 a.m. 211,584
12 m. 80,000
1 P.M. 158,688
2 P.M. 396,720
3 P.M. 608,304
4 PM. 502,512
5 P.M 449,616

5:48 p.m. 396,720
6:40 p.m. 396,720

5 P.M.

1913 Closterium
8/11 rostratum
7 AM. 6,400
8 P.M. 6,400
OPARNM ay yeeeseccactae cass
10 a.m. 52,896
11 a.m. 6,400
IPN ss Ula Peeeeneannen
1 P.M. 6,400
2 P.M. 52,896
3 P.M. 52,896
4 P.M. 52,896
' § P.M. 105,792
5:48 p.m. 52,896
G40 Bemis. cscee er
1913 Total
8/11 Algae
7AM. 31,996,026
8 am. 21,060,304
9am. 19,557,124
10 a.m. 21,066,912
llam. 20,339,776
12 M. 19,958,608
lpm. 26,413,256
2P.M. 39,724,656
3 P.M. 42,793,872
4pm. 46,524,776

61,656,448

5 :48p.M.56,696,516
6:40P.M.68,856,096

Nitzschia
acicularis

449,616
502,512
343,824
158,688
396,720
105,792
264,480
502,512

Synedra
ulna
158,688
211,584
396,720
608,304
396,720
343,824
158,688
211,584
211,584
52,896
105,792
396,720
714,096

Mougeotia
sp.
264,480
608,304
608,304
608,304
211,584
661,200
766,992
343,824
1,057,920
872,784
1,216,608
1,110,816
2,089,392

Cercomonas
crassicauda

Nitzschia
sigma

52,896
52/896
158,688

~ 343,824
158,688
"158,688
59,296

158,688
211,584

Synedra
radians

343,824
158,688
264,480
264,480
555,408
105,792
502,512
714,096
502,512
714,096
264,480
555,408

1,375,296

Staurastrum
A

6,400
52,896
6,400
52,896
105,792
12,800
52,896
264,480
105,792
158,688
52,896
158,688
105,792

Cercomonas
sp.

Nitzschia
vermicularis

"52,896
52,896
6,400

52,896
105,792
52,896
52,896

Total
Bacillariaceae
29,525,024
17,451,424
17,289,844
17,866,704
17,179,664
15,688,528
21,719,160
31,129,904
31,307,184
34,769,072
47,514,016
44,121,664
51,818,032

Staurastrum
sp.
52,896

"52,896

Chlamydomonas
sp.

211,584
105,792

“555,408
105,792
502,512

Pleurostauron
parvulum

Closterium
accuminatum

6,400
6,400

Total
Conjugatae
342,966
680,400
621,104
714,096
330,176
726,896
826,288
528,960
1,242,208
1,090,758
1,428,192
1,335,200
2/248,080

Chromulina
sp.
2,750,592
2,539,008
2,750,592
2,591,904
1,719,120
3,147,312
1,719,120
1,877,808
2}142'288
1,824,912
2,089,392
2,248,080
2,856,384

Stauroneis
phoenicenteron

“52,896

Closterium
acerosum

6,400
52,896
12,800

Total
Chlorophyll
bearing

35,677,850
24,947,312
24'220/324
25,405,888
23,936,704
25,301,712
29,217,400
42,512,800
46,497,248
49,945,672
65,839,888
60,499,184
73,644,688

Eudorina
elegaus

211,584
343,824
396,720
396,720
105,792
502,512
211,584
396,720
555,408
264,480
608/304
555,408
343,824

University of California Publications in Zoology

(Vou. 22

TABLE 5.—PLANKTON ORGANISMS Per Cusic METER IN Smitu’s CANAL,

Euglena
8/11 viridis

Sam. 6,400
"158,688
"52,896

5:48 p.m 105,792
6240) 0 ehescesceeess

1913 Platydorina
8/11 caudata
7 AM. 105,792
8 A.M 12,800
9 AM 6,400
10 a.m 54,400
11 a.m 105,792
12 M. 105,792
1pm 105,792
2 P.M 19,200
3 P.M 48,000
4 P.M 32,000
5 P.M 19,200
DAS PIMC As. seeccsteeeees
6:40 p.m 12,800

1913 Amoeba
8/11 proteus

7 AM

8 A.M

9 AM
10 a.m
11 a.m
12 mM.

1PM

QZ PIMG, \aisdecsssecetonee
3 P.M

ABIPIM SY o eeticcereeenes
DUPEMINO Ren. creat
5:48 p.m. 396,720
6:40 p.m. 396,720

1913 Nebela
8/11 sp.

7 AM.

SALE haces ceesctes
9 A.M. 105,792
10 A.M. ere
11 A.M.
12 M.

1 P.M.

QPPIMa csctec st teaeeee
3 P.M.

4 P.M.

5 PIMs) ay

5:48 P.M. . fe
6:40 p.m. 105,792

Hour y Serigs in 1913—(Continued)

Gonium
pectorale

6,400

Pleodorina
californica

25,600
52,896
32,000
52,896
158,688
60,800
67,200
158,688
32,000
25,600
112,000
54,400
48,000

Amoeba
radiosa

Nuclearia
simplex

158,688
52,896

~ 105,792
52,896
~ 211,584

Hemidinium
nasutum

264,480
105,792
502,512
608,304
396,720
396,720
158,688
158,688
105,792
449,616
158,688

52,896
449,616

Pleodorina

illinoisensis

Cyphoderia
ampulla

Total
Rhizopoda
158,688
211,584
158,688
105,792
264,480
264,480
214'584
211,584
211,584
370,272
396,720
1,110,816
1,481,088

Mallomonas
sp.

Trachelomonas Trachelomonas

euchlora
52,896

211,584

52,896
158,688

Difflugia
pyriformis

105,792

105,792
"52,896
~ 52,896

Actinophrys
sol.
"52,896
"52,896
~ 158,688
105,792

Pandorina
morum

52,896
105,792
158,688
52,896
396,720
264,480
158,688
6,400
52,896
6,400
52,896
19,200

volvocina
211,584
714,096
555,408
608,304
449,616
502,512
211,584
396,720
555,408
714,096
264.480
555,408
925,680

Hyalodiscus
sp.

~ 396,720
396,720
925,680

Heterophrys
fockei

211,584

105,792
52,896
52,896

396,720

343,824

502,512

449,616

158,688

158,688

Peridinium
einctum

Total
Mastigophora
3,681,824
3,887,008
4,663,200
4.338.976
3,596,928
5,343, 104
2,804,144
2'788,144
3,703,376
3,473,792
4,236,336
3,802,768
4,794,992

Microgromia
socialis

105,792
105,792

~ 158,688

52,896

Heterophrys
sp.

502,512
502,512
766,992
343,824
396,720

1920]

Allen: Plankton of the San Joaquin River

bo
-]
Ne)

TaBLE 5.—PLANKTON ORGANISMS PER Cusic METER IN Smitu’s Cana,
Howry Series 1n 1913—(Continued)

1913 Raphidiophrys

8/11

5 P.M.

5:48 P.M.
6:40 p.m.

Total Protozoa

1913 wit
8/11 Mastigophora
7am. 5,744,768
8am. 8,892,090
9am. 7,678,272
10 a.m. 9,476,288
llam. 8,198,880
12 M. 11,214,560
lpm. 6,363,976
2PM. 6,332,176
3Pp.M. 7,749,920
4pm. 6,594,656
5p.M. 7,455,744
5:48 p.m. is 055, 872
6:40 p.m. 9,058, 136
1913 Rotifer
8/11 unidentified
7 AM. 158,688
8 A.M. 158,688
9 A.M. 343,824
10 a.m. 158,688
11 a.m. 502,512
12 m. 343,824
1 P.M. 158,688
2 P.M. 343,824
3 P.M. 52,896
4PM. 105,792
5 P.M. 105,792
5:48 p.m. 211,584
6:40 p.m. 158,688

elegans

$19,888
555,408
661,200
1,586,880
819,888
396,720
158,688
158,688
211,584
396,720
343,824

Total
Heliozoa
211,584
211,584
105,792
158,688
105,792
158,688
396,720
1,005,024
1,005,024
1,322,400
502,512
555,408

Vorticella
sp.

1,322,400
3,411,792
1,533,984
2,591,904
2,089,392
2:433,216
1,930,704
2,036,496
1,772,016
1,428,192

925,680
1,216,608
1,375,296

Collotheca
pelagica

Cyclidium
Sp.

Halteria
grandinella

105, 792

Total
Ciliata
1,692,672
4,575,514
2,750,592
5,031,520
4,178,784
5,501,184
3,180,160
2'935,728
2'829,936
1,745,568
1,487,488
1,639,776
3,226,656

Collotheca
sp.

"52,896
105,792

sp.

sp.

Total
Bdelloida
165,088
158,688
343,824
158,688
508,912
343,824
165,088
363,024
122,192
105,792
112,192
224,384
158,688

fissa

105,792
52,896
52,896

8p-

Holophrya
sp.
264,480
661,200
1,005,024
1,824,912
1,428,192
2°195,184
925,680
555,408
661,200
264,480
4491616
52,896
1,428,192

Total
Suctoria

Total

Asplanchna
brightwellii

6,400

Tintinnidium
fluviatile

105,792
502,512
211,584
502,512
661,200
872,784
264,480
343,824
105,792

52,896

52/896
264,480
264, "480

Total Protozoa

without
Mastigophora

2,062,944
5,005,082,
3,015,072
5,137,312
4,601,952
5,871,456
3,559,832
3,544,032
4,046,544
3,120,864
3,219,408
3,253,104
4,263,144

Rotaria
rotatoria

6,400

Asplanchnopus
sp.

"105,792

105,792
“19,200
6,400

~~ 19,200
52,896

University of California Publications in Zoology

[Vou. 22

TABLE 5.—PLANKTON ORGANISMS PeR Cupic METER IN SmiTH’s CANAL,
Hourty Serres in 1913—(Continued)

1913
8/11
7 AM.
8 A.M.
9 A.M.
10 A.M.
11 A.M.
12 mM.

1 P.M.
2 P.M.
3 P.M.
4 P.M.
DUBSMY 2. Ge aionen
AS PLM cov cccareestise
6:40 P.M. ....

Brachionus
angularis
6,400
“52,896
"52,896

Brachionus
egg; attached,
male

1913
8/11
7 AM.
8 a.m.
9 A.M.
10 A.M.
11 A.M.
12 M.

1 P.M.
2 P.M.
3 P.M.
4 P.M.
5 P.M.
5:48 P.M.
6:40 P.M.

1913
8/11

7 A.M.
8 A.M.
9 A.M. 6,400
10 A.M.
11 A.M.
12 m.

1 P.M.

2 P.M.

3 P.M.

4 P.M.

5 P.M.
5:48 P.M.
6:40 P.M.

52,896

Brachionus
urceus

12,800
158,688

1913 Keratella
8/11 egg, attached

7 AM. 52,896
SUACM.. - 2.3 ;
52,896

~ 6,400

6:40 p.m. 52,896

Brachionus
angularis
caudatus

1,216,608
2,380,320
2,380,320
1,930,704
1,163,712
3,253,104
1,666,224

925,680

555,408

714,096

766,992
1,163,712
1,586,880
Brachionus

egg; free,
female

608,304
1,057,920
343,824
6 1,200
343,824
766,992
158,688
105,792
52,896
105,792
608,304
343,824

Brachionus
with parasites

6,400

Keratella
egg, free

396,720
396,720
502,512
766,992
449,616
819,888
502,512
819,888
661,200
264,480
608,304
714,096
925,680

Brachionus

budapestinensis

Brachionus
egg, winter

~ 264,480
105,792

Diurella
eke
158,688

52,896
158,688
158,688
105,792

52,896

52,896
158,688
264,480
211,584

Keratella
quadrata

211,584
396,720
343,824
502,512
264,480
264,480
60,800
211,584
67,200
52,896
52,896
158,688
264,480

Brachionus
ealyciflorus

158,688
396,720
264,480
264,480
158,683
211,584

80,000
140,800
158,688
105,792

80,000
105,792
158,688

Brachionus
male

Filinia

egg, free

661,200
714,096
555,408
555,408
396,720
766,992
502,512
449,616
105,792
158,688
396,720
449,616
608,304

Polyarthra
trigla

766,992
1,586,880
2,248,080
1,322,400
1,877,808
1,824,912
1,005,024
1,269,504
1,269,504

608,304

766,992
1,057,920

872,784

Brachionus
capsuliflorus

25,600
12,800
41,600

105,792
67,200

105,792
12,800
19,200

6,400
52,896
25,600
25,600
25,600

Brachionus
patulus

6,400

Filinia
longiseta

6,400

Polyarthra trigla
egg; attached,

female

105,792
158,688
52,896
105,792
52,896

Brachionus
egg; attached,
female

52,896

264,48
52,896
52/896
52,896

158,688

211,584
264,480
396,720

Brachionus
plicatilis

Keratella
cochlearis

52,896

Rotifer egg,
winter

52,896
6,400
105,792
105,792
52,896
264,480
105,792
52,896
158,688
52,896
52,896
52,896
25,600

Allen: Plankton of the San Joaquin River 281

TABLE 5.—PLANKTON ORGANISMS PER Cusic METER IN SMITH’s CANAL,

1920]
1913 Synchaeta
8/11 sp.
, AUER ees Sone.
8 A.M 52,896
9 AM 52,896
10 a.m sates
11 a.m 52,896
12m 6,400
1PM econ S
2 P.M 6,400
3 P.M 6,400
4 P.M shai
5 P.M

5:48 p.m. 158,688
GSH OPA. cc.sede ates

1913
8/11 Sida
7 AM. 52,896
8 A.M. 12,800
9 A.M. 12,800
10am. 25,600
11 a.m. 6,40)
12 mM. 19,200
1 P.M. eee
2 P.M. 19,200
3 P.M. 52,896
4 P.M. 52,896
5 P.M.

5:48 P.M. 6,400
6:40 p.m. 12,800

Hour.y Series In 1913—(Concluded)

Trichocerca Trichocerca Total
capucina iernis Ploima
158,688 4,564,560
158,688 7,466,640
Pee antes 343,824 4,846,384
52,896 264480 7,199,408
was cbevese Sees 714,096 5,759,920
12,800 766,992 9,612,576
343,824 4,979,936
211,584 4,817,607
211,584 3,575,840
32,000 2,721,600
25,600 3,512,752
ee 211,584 5,471,152
cane 264480 6,199,188
Total Total
Cladocera Cyclops Nauplius Copepoda
105,792 158,688 158,688 317,376
12,800 86,400 158,688 245,088
65,696 86,400 105,792 192,192
25,600 54,400 158,688 213,088
6,400 73,600 80,000 153,600
19,200 54,400 211,584 265,984
52,896 25,600 86,400 112,000
19,200 80,000 92,800 172,800
52,896 60,800 12,800 73,600
52,896 60,800 52,896 113,696
6,400 99,200 105,792 204,992
6,400 99,200 52,896 152,096
19,200 140,800 105,792 246,592

Total Bosmina
Rotifera longirostris
4,729,648 52,896
7,615,328 Serer kEeOD
5,196,608 52,896
TEALO\G OOM
6,268,832
9,956,400 __......
5,145,024 52,896
5,180,631
3,704,432 ;
2,852,992 6,400
3,631,344 6,400
5,708,336
7,357,876 6,400
Total Total
Entomostraca Organisms
423,168 42,893,610
257,888 37,825,610
257,888 32,689,892
238,688 38,192,880.
160,000 34,967,488
285,184 41,414,752
164,896 38,087,152
192,000 51,429,463
126,496 54,374,720
172,992 56,092,520
211,584 72,902,032
158,496 69,619,120

265,792

85,531,500

282 University of California Publications in Zoology [Vou 22

TABLE 6.—VoLuMEs oF Catcues, 1913

Volume in cubic Estimated Number Number of
centimeter per 4 percentage of of forms
Date cubic meter plankton hauls recorded
1913 ————— eS
I Il Ill I Il Ill I II III I Il Ill
1/5 |0.5 |0.4 50% | 40% 13° 7 30 | 31
1/8 | 0.55 50% 13 28
1/11 O55 | ale 40% 25 24
1/12 | 0.35 | 0.25 30% | 50% 13| 7 30 | 37
1/15 | 0.8 60% 13 42
1/19 | 0.55 | 0.35 | 0.55 | 60% | 60% | 40% | 8| 7| 13] 43 | 45 | 41
Be 08" | ove: | 012s |” | 20m | soes| Wa | onl leanne
2é 70 To
1/26 | 1.0 9 39
1/29 | 0.8 90% 8 46
2/2 | 0.85 | 0.65 | 0.6 | 85% | 75% | 80% | 9| 7113] 45 | 50 | 51
2/5 | 0.95 85% 9 48
2/8 |1.0 |0.85|0.6 | 80% | 70% | 30% | 9| 7| 13) 46 | 49 | 45
2/12 | 1.7 85% 10 50
2/15 11.0 | 0.75 | 0.65 | 80% | 60% | 80% | 9| 7|13| 54] 50 | 59
2/19 | 0.85 60% 9 61
2/23 |1.55|0.65|0.6 | 70% | 60% | 70% | 9| 7 | 13| 60 | 62 | 64
2/26 | 1.65 60% 1B 59
3/1 | 1.4 | 0.65 | 0.75 85% | 40% | 50% | 9 | 7 | 13 | 55 | 52 | 57
3/5 | 3.95 85% 13 46
3/3 |5.2 |1.4 | 0.65| 85% | 10% | 50% | 9| 71] 13] 48 | 52 | 60
3/12 | 6.8 80% | . 16 43
ne 18 |1.95|0.8 | 90% | 15% | 50% | 10| 7| 131 55 | 58 | 70
3/19 | 2.1 80% 13 56
3/23 1.9 0.8 | 0.8 85% 10% | 60% 2 7/13 63 74 | 70
p . 5% © «
3/29 |1.85|0.7 |1.0 | 80% | 15% | 40% | 9| 7/113) 54| 78 | 72
0% 9 57
Te Be Wage loess 308 15% | 40% | 9| 5113158 | 75 | 71
4/9 |2.4 95% 9 54
4/13 | 1.85 | 0.5 | 0.75 | 95% | 15% | 20% | 9] 5 | 12 | 62 | 70 | 67
4/16 | 2.2 80% 10 | 56
4/19 | 2.65 | 1.85 | 0.7 90% 10% | 75% | 13 | 5| 13] 47 | 58 | 61
4/23 | 2.2 85% 9 65
4/26 | 3.1 |0.8 | 0.55 | 90% | 20% | 25%) 13| 5 | 13] 70 | 68 | 71
4/30 | 2.3 80%, 9 51
5/3 | 21 | 3.05 | 0.65 | 65% | 4% | 50%] 9] 5| 13) 53 | 58 | 63
5/7 | 2.6 90% 9 55
5/10 |3.0 |6.6 | 0.55 | 95% | 4% | 80%| 9] 6| 12] 64 | 47 | 56
5/14 | 2.8 90% 9 51
3/17 | 3.4 | 5.6 | 0.65) 10%| 4% | 55% | 9| 6 | 13| 65 | 64 | 70
5/21 | 2.25 85% 9 49
3/24 |2.75|6.0 |0.6 | 50%| 5% | 50%) 8| 5| 9] 50| 59 | 58
5/27 | 2.95 80% 9 58
5/31 13.6 |6.7 | 0.7 80% 2% | 90% | 9] 3 | 13 | 53 | 52 | 46
6/3 | 2.9 | 95% 9
6/7 12.4 |3.15|0.5 | 95%| 5% | 45%| 9| 3! 9 54 | 60 | 66
6/11 | 2.8 55% 9 5
6/16 | 1.85) 1.9 |0.6 | 65% | 4% | 50%) 9| 6] 13 65 63 | 61
6/18 | 2.65 85% 9
6/21 12.8 |1.2 | 0.6 | 90% | 10% | 60%) 9| 7 | 13 a7 68 | 78
6/25 | 3.45 920, 13
6/28 13.1 | 1.95 | 0.75 | 92% | 15% | 65% | 13| 9 | 13 61 77 | 72
7/3 |2.7 80% 9 56
7/5 13.05 | 0.95 | 0.7 | 93% | 30% | 65% | 9| 9| 13 63 66 | 72
7/9 12.7 85% 9 5
712 | 3.85 |2.1 |1.7 | 90% | 40% | 85%) 9| 9 | 13 | 55 | 82 | 94
7/16 | 3.9 920, 9 57

1920] Allen: Plankton of the San Joaquin River 283
TABLE 6.—VOLUMES oF CatcHEs, 1913—(Concluded)
auocnntenet og pene taeeot Ee ae,

Date cubic meter plankton hauls recorded

. I II III I II III ih |) tue |) amie |) se |) ane |} aoe
oe ae 1h 0.95 ee 60% | 80% 9 en 2 66 | 60
is rae 1.4 1.65 ne 90% | 50% H 10 | 13 ae 70 | 83
S A ae 2.3 1.35 a 80% | 90% ; 9 | 13 re 88 | 76
ole nee 2.4 2.85 ve 75% | 50% 5 9 | 13 ee 83 | 98
a He 2.3 1.4 Bae 80% | 70% 2 9} 13 @ 98 | 44
ae ce 2.0 4.6 ee 85% | 80% 5 8 | 13 iN. 86 | 92
ae a 9) |) 2 oe 90% | 80% 3 8 | 13 Be 84 | 78
5) 8 8 2.0 2.8 badd 90% | 80% 3 8 | 13 a 66 | 85
as 28 2.5 278) fas, 55% | 85% 9 | 13 ee 81 | 79
SB rae 1.9 iL 8) age 85% | 95% , 9 | 13 3s 78 | 67
A suo 2.5 1.55 200 30% | 90% : 9} 13 ie 70 | 76
ip : ee 1.65 | 1.8 ee 30% | 55% q 7 || 263 ef 74 | 72
“a ira 2.1 1.55 oon 30% | 40% 3 8 | 13 ze 74 | 73
ee rat 1.25 | 1.45 oe 30% | 40% 3 8 | 13 a 68 | 53
ia seek 1.2 1.35 Bae 25% | 40% 2 9 | 13 of 62 | 75
a) 2 ae 1.2 1.2 350 30% | 50% 5 9} 13 ei 76 | 71
ai Hee 1.3 1.5 aa 20% | 15% 5 9} 19 aa 57 | 66
Tie pee. 0.8 0.6 fees 25% | 45% io 9 | 13 a 64 | 65
es ieee 0.7 0.95 400. 15% | 20% : 9513 a 67 | 81
ois ee eal 0.6 rae 45% | 25% 8 9 | 18 @ 57 | 62
oi ne 0.8 ii ee 50% | 35% 2 8 | 13 a 46 | 61
ae eee 0.8 0.85 ae 25% | 25% B i \\ dle o 49 | 52
ioe eae 0.5 0.65 ae 25% | 20% 2 of Ny ale a 56 | 40
a ae 1.30 | 0.7 ne 15% | 10% 4 0) 83 a 54 | 51

Se

284 University of California Publications in Zoology |Vou. 22

Dairy, Station I. Hourty, Sration IIIa.
ed
£35 255
Beg 28 Bag 2
Date ass zy xs x) -) Date asic G) aS x) x
1913 | ‘ses | S28 | Ba 1913 ons | sa8 | 8 Ba
Bae | Bee |ee| ge | au | BEE} Boa) ga | ge
esx | gas | 3a) ge SéX | eas | 2a | ge
7/5 3.05 | 93% 9 63
7/6 2.5 70% 9 57
We ul 3.2 75% 9 54
7/8 3.6 80% 9 55
7/9 Qa 85% 9 59
7/10 3.4 90% 9 54
7/11 4.1 85% 9 45 | 7 aM. 2.4 50% 6 76
7/12 3.85 | 90% 9 55 | 8 a.m. 253 60% 6 74
7/13 5.05 | 92% | 12 56 | 9 a.m. 2.3 70% 6 75
7/14 4.35 | 80% 9 64 | 10 a.m. 2.5 50% 6 73
7/15 4.40} 90%) 10 55 | 11 a.m. 2.4 50% 6 79
7/16 3.9 92% 9 57 | 12 m. 2.4 75% 6 78
7/17 4.65 | 50%) 10 50 | 1P.m. 2.07 | 80% 6 81
7/18 6.4 90% | 13 50 | 2 P.M. 2.07 | 75% 6 80
7/19 4.1 85% 9 50 | 3 P.M. 2.07 | 85% 6 91
7/20 4.9 92% 9 52 | 4 P.M. 2.07 | 85% 6 86
7/21 4.3 92% 9 54] 5 pM. 2.3 80% 6 94
7/22 4.2 92% | 13 56 | 5:48p.m.) 2.3 85% 6 86
7/23 3.9 85% 9 52 | 6:40p.m.) 2.5 80% 6 93
7/24 3.35 | 95% 9 64
7/25 3.85 | 92% 9 57
7/26 4.3 90% 9 63
7/27 5.8 95% | 13 67
7/28 4.45 | 95% 9 62
7/29 4.3 95% 9 64
7/30 4.5 92% 9 61
7/31 4.2 90% 9 59
8/1 3.8 92% 9 53
8/ 2 4.2 90% 9 66
8/ 3 3.7 95% 9 64
8/ 4 3.6 95% 9 65

1920] Allen: Plankton of the San Joaquin River 285
TABLE 7.
Temperature Number
Date Bee centigrade Me Water pacer of hauls
1913 | oollection conditions conditions drift
I TS Loe I | Sone

1/ 1} 3:30 p.m.| Air Clear a 13
Water

1/ 5| 4:00 p.m.| Air 4.5 High wind; clear Rough a i
Water 4

1/ 8| 5:00 p.m.| Air 2.5 Wind; sleet Choppy a 13
Water | 5.5

1/11} 3:00 p.m.| Air 6.5) Wind; cloudy Choppy a 25
Water 4

1/12) 2:00 p.m.| Air ~ | 13 |15 Wind; clear Choppy a 13 7
Water | 6.5/13

1/15] 4:00 p.m.) Air 9 Cloudy a 13
Water | 7

1/19)11:00 a.m.| Air 8 |11 | 9.5} Wind; clear Choppy d 3 ll 7 || als}
Water | 8.5/8 | 8

1/22| 4:00 p.m.} Air 9.5 No wind; rain Smooth d 9
Water |10

1/25] 2:00 p.m.) Air 17 |19 | No wind; clear Smooth d 6 | 25
Water 8 10

1/26'10:00 a.m.) Air 14 No wind; clear Smooth d 9
Water (10

1/29} 4:00 p.m.| Air 17.5 Light wind; clear | Wavy d 8
Water {11.5

2/ 2'11:30 a.m.| Air 14 {17.517 | Breeze; clear Ripply d Ohi 7 || as}
Water j11 |10 10 ‘

2/ 5) 4:00 p.m.| Air 16.5 No wind; cloudy Smooth d 9
Water {12.5

2/ 8/10:30 a.m.| Air 15 |15 |16 | Light wind; rain Wavy d Oy 7 | us}
Water /14.5/10.5)11.5

2/12) 4:00 p.m.} Air 19 Breeze; clear Ripply d 10
Water 15.5

2/15)10:00 a.m.| Air 18 |19 |15.5) No wind; clear Smooth d ll ae || ils
Water (15 |13.5/13

2/19} 4:00 p.m.} Air 14.5 High wind; clear Rough a 9
Water {12.5

2/23) 9:00 a.m.| Air 10 |12 |13 | High wind; Rough a @) | 70 |! als}
Water |11.5) 9 | 9 part cloudy

2/26| 4:00 p.m.| Air 13 High wind; cloudy | Rough a 13
Water {12 j

3/ 1} 1:00 p.m.| Air 13.515 |15 Light wind; cloudy) Wavy a 9 1) 183
Water {13 |10 /|10

3/ 5) 4:00 p.m.| Air 23.5 Light wind; clear | Wavy a 13
Water |15

3/ 8} 9:30 a.m.|. Air 23 |21.5)22.5] Light wind; clear | Wavy a Git, 2 js}
Water {18 |15 /15

3/12) 4:00 p.m.| Air 17.5 Light wind; clear | Wavy a 16
Water |16.5)

3/15) 9:00 a.m.| Air 14.5)12 |11.5) Breeze; clear Ripply a LOM Zin els
Water |14.5)12 12

3/19) 4:00 p.m.| Air 14.5 High wind; Rough a 13
Water |14.5 part cloudy

3/23) 9:00 a.m.| Air 12 | 9.513 | Wind; cloudy Choppy a 9} 7) 13
Water |14 |12 /12.5

3/26) 4:30 p.m.| Air 18 Breeze; clear Ripply a 13
Water {14.5

3/29} 9:00 a.m.| Air 20 |17 {18.5} Wind; clear Choppy a 9 7 | 13
Water |12 {13 |14.5

4/ 2) 4:30 p.m.| Air 18 Light wind; clear | Wavy a 9
Water |17

286 University of California Publications in Zoology [ Vou. 22

TABLE 7.—(Continued)

- Temperature Number
Date pase ot centigrade Air Wate Anchor of hauls
1913 | collection conditions conditions drift
I | W | I ev acy!) iiiue
4/ 5) 9:00 a.m.} Air 15.513.5)15 | Wind; cloudy Choppy a 9} 5] 138
Water |18 /|14.5/15
4/ 9)12:00 mw. | Air 24 Breeze; clear Ripply a 9
Water (|18
4/13} 9:00 a.m.| Air 18.5|16.5|/17 | Breeze; part cloudy| Ripply a 9} 5 | 12
Water /18.5]17.5)17.5
4/16} 4:00 p.m.! Air 24 Breeze; clear Ripply a 10
Water |20
4/19) 9:00 a.m.| Air 21 |18 |19 | Breeze; clear Ripply a 13 | 5 | 13
Water |19 |15 {16.5
4/23) 4:00 p.m.| Air 25 Breeze; clear Ripply a 9
Water |20
4/26| 9:00 a.m.| Air 26. 5/23 .5/24.5) Breeze; clear Ripply a 13 | 5] 13
Water |20 {18.5/19
4/30| 4:00 p.m.| Air 20 Wind; clear Choppy a 9
Water /|19
5/ 3} 8:45 a.m.| Air 23 |21 |22 | Light wind; clear | Wavy a 9i;|| Salts
Water |18 |14 {16
5/ 7|11:00 a.m.) Air 22 Light wind; clear | Wavy a 9
Water |20
5/10} 9:00 a.m.} Air 22 |21.521.5| Wind; part cloudy | Choppy a 9} 6| 12
Water |21 |17 (|20.5)
5/14) 4:00 p.m.| Air 26 Wind; clear Choppy a 9
Water /21
5/17/12:00 m. | Air 26 |25 |26 | Wind; cloudy Choppy a 9) 6] 13
Water /21 {19 {19
5/21) 4:00 p.m.| Air Pare fay Light wind; Wavy a 9
Water [23 part cloudy
5/24) 9:00 a.m.| Air 26.5/27 |25.5| Light wind; clear | Wavy a yf) fs) )) 2)
| Water |238 |19.5/21
5/27) 4:00 p.m.| Air 18 Light wind; rain Wavy a 9
Water |23
5/31/12:00 m. | Air 31 |30.5/32 | Breeze; clear Ripply a 9} 3] 138
Water |27 {19.527
6/ 3| 5:30 p.m.) Air 22.5 Breeze; cloudy Ripply a 9
Water |25
6/ 7| 9:00 a.m.| Air 23 |23.5)/22.5| Wind; part cloudy | Choppy a CE sy || 4!)
Water |25 |20.5/22.5
6/11) 4:00 p.m.) Air 29 Wind; clear Choppy a 9
Water [23
6/16) 6:45 a.m.| Air 21 No wind; clear Smooth d 9
Water /|20
6/16) 4:00 p.m.| Air 27 |24 ! Wind; clear Choppy d 6 | 138
Water 21 |21
6/18) 1:00 p.m.| Air 25 Breeze; cloudy Ripply d 9
Water |22
6/21) 9:00 a.m.| Air 30 |28.5/28 | Wind; clear Choppy d 9| 7) 138
Water |23.5/26.5)/29
6/25) 1:30 p.m.) Air 22 High wind; Rough d 13
Water /22.5 part cloudy
6/28] 9:00 a.m.| Air 23.5/21 |22.5) Wind; clear Choppy d 13} 9] 13
Water |23 |20 [20.5
7/ 3) 9:00 a.m.| Air 24 Wind; clear Choppy d 9
Water (23.5
7/ 5| 9:00 a.m.| Air 32 |28.5/30.5) No wind; hazy Smooth d 9 9} 13
Water |26 /23.5/25
7/ 9/10:30 a.m.| Air 31 Light wind; clear | Ripply d 9
Water [26

1920] Allen: Plankton of the San Joaquin River 287

TABLE 7.—(Continued)

e Temperature Number
Mate dinero centigrade Ace Water eee of hauls
1913 collection conditions conditions drift
|| ioe |jpsuaae iar |) gate

7/12) 8:40 a.m.| Air 32 [32 No wind; clear Smooth d 9} 9} 13
Water |27 |25

7/16|10:45 a.m.) Air 28 Breeze; clear Ripply a 9
Water |26

7/19)10:00 a.m.| Air 29 |26 |27.5| Breeze; hazy Ripply a @)}) 2) als}
Water |27 |24 |25

7/23|10:30 a.m.| Air . |27 Breeze; light rain | Ripply a 9
Water |25

7/26) 9:00 a.m.) Air 26. 5/22.5|24.5) Breeze; part cloudy| Ripply d 9} 10} 138
Water |26 [23 |24.5

7/30|10:40 a.m.) Air 21.5 Breeze; hazy Ripply a 9
Water |25.5

8/ 2| 8:45 a.m.) Air 27.5!25.5/26.5| No wind; clear Smooth a ) |) &) |) al
Water |26 /24 |25

8/ 6|10:30 a.m.) Air 33 Breeze; clear Ripply a 9
Water |27

8/ 9| 8:45 a.m.| Air 29 |24.5)25 | Breeze; part cloudy| Ripply a 9} 9} 138
Water |27 |25 (|25.5 .

8/13)11:00 a.m.| Air 24 Light wind; clear | Wavy a 9
Water |26.5

8/15] 9:00 a.m.| Air 22.5/23.5/24 | Breeze; hazy Ripply A Oy) BI) als}
Water |23.5/23 |24

8/20)11:30 a.m.| Air 32.5 Breeze; hazy Ripply a 9
Water |26

8/23) 8:40 a.m.| Air 33 |29 |32.5| Breeze; hazy Ripply a tO) |) 33 ff 83
Water |28 |24.5/25

8/27|11:00 a.m.| Air 32.5 No wind; cloudy Smooth a 9
Water |27

8/30} 8:45 a.m.) Air 33 |380.5)/31.5| Breeze; hazy Ripply a 9} 8} 13
Water |28 |26 [27

9/ 2)12:00 m. | Air 24 Breeze; part cloudy} Ripply a 9
Water |26.5

9/ 6} 9:15 a.m.) Air 30 |26.5|27.5| Breeze; hazy Ripply a 9} 8} 13
Water |26 /|24 |24

9/ 9)12:40 p.m.| Air 28 Breeze; hazy Ripply a 9
Water |26

9/13) 9:00 a.m.} Air 24.5/21 |23 | Breeze; clear Ripply a Gy 1} ais}
Water |25 —|23.5,23.5

9/17, 5:00 p.m.| Air Sono No wind; clear Smooth a 9
Water |27

9/20} 9:00 a.m.} Air 23.5/22.5)23 | Breeze; cloudy Ripply a 9) 9) 18
Water |26 |23.5/23.5

9/241 5:00 p.m.| Air 24.5 Breeze; clear Ripply a 9
Water |22.5

9/27| 7:30 a.m.| Air 23 .5/21.5/20.5) Breeze; clear Ripply a 9} 9] 13
Water |22 (|20.5/20.5

10/ 1) 4:15 p.m.| Air 29 Breeze; clear Ripply a 9
Water |22

10/ 4) 8:00 a.m.| Air 20 |19 |17 | Breeze; clear Ripply a S) | @ |] ale
Water |21 /|20 |20

10/ 8; 5:00 p.m.| Air 18.5 Wind; clear Choppy a 9
Water {19.5

10/11) 7:00 a.m! Air 22 /21.5)14 | No wind; clear Smooth a CO) | ts}! |} als
Water |19.5/17 {17

10/15) 5:00 p.m.| Air 21 No wind; clear Smooth a 9
Water {18.5

10/18} 8:00 a.m.| Air 23.5)19.5|19 | No wind; clear Smooth a 9} 8] 13
Water |19 |17.5/17

O00,

288 University of California Publications in Zoology [ Vou, 22

Tasie 7.—(Concluded)

; Temperature Number
Date ane oF centigrade nes Water Anchor of hauls
1913) Woallantion conditions conditions deift
I II Ill I EY a DEY
10/22} 5:00 p.m.| Air 25 No wind; clear Smooth a 9
Water (20 f
10/26} 2:00 p.m.| Air 22.5/27 |24 | Breeze; clear Ripply d 9; 9] 13
Water |19 |18 {18
10/29) 4:30 p.m.) Air 16 Breeze; cloudy Ripply a 9
Water /19
11/ 2/10:00 a.m.| Air 19 |19.5/17.5) No wind; cloudy Smooth a 9} 9] 13
Water |19.5/17 |17
11/ 5| 4:30 p.m.| Air i7/ No wind; cloudy Smooth a 9
Water {18.5
11/ 8)10:00 a.m.} Air 20 |17 |18 | No wind; cloudy Smooth a 9; 9] 19
Water |19.5)16.5)17
11/12) 4:45 p.m.| Air 13 Wind; cloudy Choppy a 9
Water |17.5
11/15} 8:45 a.m.| Air Gm | LS No wind; fog Smooth a 9; 9] 13
Water |17.5/15.5/15
11/19} 5:45 p.m.| Air 14.5 Wind; cloudy Choppy a 13
Water (16
11/22)11:00 a.m.} Air 15 |13 /12.5) Breeze; clear Ripply a 9; 9) 13
Water {15 |12 {13
11/26] 7:30 a.m.| Air 9 No wind; cloudy Smooth a 9
Water |13
11/30} 1:00 p.m.| Air 13 |14 |13 | Wind; clear Choppy a 12 | 9 | 13
Water {13 /|10 {11
12/ 3) 4:45 p.m.| Air 14 No wind; clear Smooth a 13
Water |10
12/ 6'11:00 a.m.| Air 6.5] 4.5] 6 No wind; fog Smooth a 9; 8} 13
water /11 7.5) 8
12/10) 4:30 p.m.} Air 8 No wind; fog Smooth a 7
Water | 9
12/14/11:00 a.m.| Air 13.5]/14 |14 | Wind; clear Choppy a A P|) alr
Water {12 9 9.5
12/17) 4:30 p.m.| Air 10 No wind; cloudy Smooth a 7
Water |12
12/20) 2:00 p.m.| Air 9 9.5) 9.5) No wind; cloudy Smooth a 9 Ziel) ales
Water |11.5) 8.5) 9
12/24) 2:00 p.m.| Air 12 Light wind; cloudy) Wavy a ia
Water (13
12/27|10:00 a.m.| Air 9 | 9.5) 9 | Light wind; cloudy) Wavy a 9) 7 aS
Water |11.5) 9 9
12/31)11:00 a.m.| Air 16 High wind; cloudy | Rough a 9
Water {11.5
Average for | Air 20.619.5|19.6
the year Water |19 |16.7117.3

Allen: Plankton of the San Joaquin River

1920] 289
Tasie 8.—Datty Co.iections Sration I
Date es Temperature Air Water LEE ues
1913 Rollection centigrade conditions conditions drift heals
7/5 \11:20 a.m. | Air 32 No wind; hazy Smooth d 9
Water = |26
7/ 6 | 9:30 a.m. | Air 32.5 | No wind; clear Smooth d 9
Water (26
7/ 7 | 8:30 a.m. | Air 29.5 | Breeze; clear Ripply d 9
Water (|26
7/8 | 1:30 p.m. | Air 34.5 | Wind; hazy Choppy d 9
Water (|27
7/ 9 10:30 a.m. | Air 31 Light wind; clear | Wavy d 9
Water (|26
7/10 {10:45 a.m. | Air 32 - Wind; hazy Choppy d 9
Water |26
7/11 |10:45 a.m. | Air 35 Breeze; clear Ripply d 9
Water {26.5
7/12 |10:55 a.m. | Air 32 No wind; clear Smooth d 9
Water |27
7/13 |12:00 m. Air 29.5 | Wind; clear Choppy d 12
Water (|27
7/14 |10:30 a.m. | Air 26 No wind; clear Smooth d 9
Water (|26
7/15 |10:45 a.m. | Air 25.5 | No wind; clear Smooth d 10
Water |26
7/16 {10:45 a.m. | Air 28 Breeze; clear Ripply a 9
Water |26
7/17 |\10:45 a.m. | Air 30.5 | Breeze; clear Ripply a 10
Water |26
7/18 | 2:00 p.m. | Air 32 Breeze; part cloudy| Ripply a 13
‘ Water /26.5
7/19 |11:50 a.m. | Air 29 Breeze; hazy Ripply a 9
Water |27
7/20 |10:00 a.m. | Air 26 Breeze; part cloudy| Ripply a 9
Water = |26
7/21 |10:45 a.m. ; Air 27 No wind; Smooth a 9
Water (26.5 part cloudy
7/22 |10:30 a.m. | Air 23 No wind; rain Smooth a 13
Water |25
7/23 |10:30 a.m. | Air 27 Breeze; rain Ripply a 9
Water |25
7/24 |10:30 a.m. | Air 26 Breeze; hazy Ripply a 9
Water (25.5
7/25 |11:30 a.m. | Air 24 Breeze; part cloudy} Ripply a 9
Water |25
7/26 |12:30 p.m. | Air 26.5 | Breeze; part cloudy! Ripply d 9
Water (|26
7/27 \10:40 a.m. | Air 24.5 | Breeze; clear Ripply a 13
Water (|25
7/28 |10:50 a.m. | Air 25 Breeze; hazy Ripply a 9
Water (25.5
7/29 |\10:45 a.m. | Air 25 Breeze; hazy Ripply a 9
Water (25.5
7/30 |10:40 a.m. | Air 27.5 | Breeze; hazy Ripply a 9
Water |25.5
7/31 {11:00 a.m. | Air 26.5 | Breeze; hazy Ripply a 9
Water (|26.5
8/ 1 {11:00 a.m. | Air 24.5 | Breeze; part cloudy) Ripply a 9
Water (|26
8/ 2 |11:07 a.m. | Air 27.5 | No wind; clear Smooth a 9
Water |26
8/ 3 {10:50 a.m. | Air 28.5 | Breeze; hazy Ripply a 9
Water (/25.5
8/ 4 |10:30 a.m. | Air 27 Breeze; part cloudy} Ripply a 9
Water /25.5

290 University of California Publications in Zoology [Vou. 22
Taste 9.—Hourty CoLuections, Station Illa
Date Time Temperature Air Water Anchor | Number
1913 Fa Neves cenhiemis conditions conditions ditt haula
8/11 | 7:00 a.m. | Air 19.5 | Breeze; hazy Ripply d 6
Water /|24
8/11 | 8:00 a.m. | Air 20.5 | Breeze; hazy Ripply d 6
Water /24.5
8/11 | 9:00 a.m. | Air 22.5 | Light wind; hazy | Wavy d 6
Water [25
8/11 |10:00 a.m. | Air 24 Light wind; hazy | Wavy d 6
Water /25.5
8/11 |11:00 a.m. | Air 27 Light wind; hazy | Wavy d 6
Water [26
8/11 |12:00 m. Air 28 Light wind; hazy | Wavy a 6
Water |26.5
8/11 | 1:00 p.m. | Air 29.5 | Wind; hazy Choppy a 6
Water 26
8/11 | 2:00 p.m. | Air 29.5 | Wind; hazy Choppy a 6
Water 26
8/11 | 3:00 p.m. | Air 30 Wind; hazy Choppy a 6
Water |26
8/11 | 4:00 p.m. | Air 29.5 | High wind; hazy Rough a 6
Water 26
8/11 | 5:00 p.m. | Air 26 High wind; hazy Rough a 6
Water [25.5
8/11 | 5:48 p.m. | Air 25.5 | High wind; hazy Rough a 6
Water [25.5
8/11 | 6:40 p.m. | Air 20.5 | High wind; hazy Rough a 6
Water [25

1920] Allen: Plankton of the San Joaquin River 291

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(Owing to lack of time the writer is unable to present an exhaustive biblio-
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1911. The inland lakes of Wisconsin. Wisconsin Survey Bull., no. 22.

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CHopAT, R.

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Cuapp, W. B., and HrensHAw, F. F.
1911. Surface water supply of the United States, 1909. XI, California,
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1905. Preliminary report on the Protozoa of the fresh waters of Connec-
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HarrinG, H, K.
1913. Synopsis of the Rotatoria. U.S. Nat. Mus., Bull. no. 81.

HerRIcK, C. L.
1895. Kntomostraca of Minnesota. Geol. Nat. Hist. Surv. Minn., 2d Rep.
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Hupson, C. T, and Gossr, P. H.
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1906. Ensayo sobre los protozoos de las aguas dulces de Chile. Santiago,
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JENNINGS, H. 8S.
1901. Rotatoria of the United States, with special reference to those of the
Great Lakes. Bull. U. S. Fish Comm., 19, 1899.
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1880. Manual of the Infusoria, including a description of all known fla-
gellate, ciliate, and tentaculiferous Protozoa, British and foreign.
3 vols., London, Bogue.
Koror, C. A.
1903. Plankton of the Illinois River, 1894-1899. Bull. Ill. State Lab. Nat.
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1908. Ibid., 8, no. 1.

Se

292 University of California Publications in Zoology [Vou 22

LEIpy, JOSEPH

1879. Fresh-water rhizopods of North America. U.S. Geol. Surv. Terr., 12.
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PRITCHARD, A.
1861. A History of the Infusoria, including the Desmidiaceae and Diato-
maceae, British and foreign; ed. 4. London.

REIGHARD, J. E.
1894. Biological examination of Lake St. Clair. Bull. Mich. Fish Comm.,
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ScHOENICHEN, W., and KALBERLAH, A.
1909. B. Eyferth’s Hinfachste Lebensformen des Tier-und Pflanzenreiches:
ed. 4. Braunschweig, Goeritz.

SroKEs, ALFRED C.
1887. Microscopy for beginners. New York, Harper.

TILDEN, JOSEPHINE
1910. Minnesota Algae. Geol. Nat. Hist. Surv. Minn., Botanical series, 8.

UniItTep STATES ENGINEERING DEPARTMENT
1908. Survey of San Joaquin River, Stockton Channel, ete. House doc.
1124, 60 cong., 2 sess., serial no. 5435.
Warp, H. B.
1897. Biological examination of Lake Michigan. Bull. Mich. Fish Comm.,
no. 6.
WEBER, E. F.
1898. Faune rotatorienne du bassin du Léman. Rev. suisse Zool., 5, 263-785.

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UNIV. CALIF, PUBL. ZOOL. VOL. 22 [ALLEN] PLATE 9

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UNIV. CALIF, PUBL. ZOOL, VOL. 22 [ALLEN] PLATE 12

Station I Station If

Station III Station IV

San Joaquin Plankton Collecting Stations

UNIVERSITY OF CALIFORNIA PUBLICATIONS— (Continued)

2 figures in text, ‘plate 13. October,:1917 220... Seba |

P 12. A Synopsis of the Bats of California, by Hilda Wood Grinnell. Pp. 223-404,
Plates 14-24, 24 text figures.. January 31, 1918 2... eee 2,00

13, The Pacific Coast Jays of the Genus Aphelocoma, by H. S. Swarth. Pp.
405-422, 1 figure in text. February 23, 1918 00 20

14, Six New Mammals from the Mohave Desert and Inyo Regions of California,
by Joseph Grinnell, Pp. 423-430.

15, Notes on Some Bats from Alaska and British Columbia, by Hilda Wood
Grinnell, Pp. 431-433.

Nos, 14 and 15 in one cover. April, 1918 22 oie ecco cecece ce ceeenseeteenee 15

16. Revision of the Rodent Genus Aplodontia, by Walter P. Taylor. Pp. 435-
504, plates 25-29, 16 text figures. May, 1918 2o2c cn ececceedeceeecceen ery /)

17. The Subspecies of the Mountain Chickadee, by Joseph Grinnell. Pp. 505-
Ob, SOLE b PLES: May, EOL SE. See Sie i ah eee 15

18. Excavations of Burrows of the Rodent Aplodontia, with Observations on
the Habits of the Animal, by Charles Lewis Camp, Pp. 517-536, 6 figures
INnGeRb. SIRNG,, LOLS) ieee see aa aS Rhee aks A hry at
Index, pp. 537-545,

Vol. 18. 1. Mitosis in Giardia microti, by William C. Boeck. Pp. 1-26, plate-1. Octo-
jE SUEY fate ah On NE Rares Se Sate ne RED alee Sr orc Re oes SEE RoE Oe 35

‘9 2. An Unusual Extension of the Distribution of the Shipworm in San Fran-
: cisco Bay, California, by Albert L. Barrows. Pp, 27-43. December, 1917. .20

3. Description of Some New Species of Polynoidae from the Coast of Cali-

fornia, by Christine Essenberg. Pp. 45-60, plates 2-3. October, 1917...... 20
4, New Species of Amphinomidae from the Pacific Coast, by Christine Essen-
berg. Pp. 61-74, plates 4-5, October, LOU onc... ececcsetccececeectee penne eeeneeeeen +15

Peta Eee eats SO oF eee ea AN ER ASN, Sou 15
6. On the Orientation of Erythropsis, by Charles Atwood Kofoid and Olive
Swezy. Pp. 89-102, 12 figures in text.- December, 1917 ........00- wee 15

7. The Transmission of Nervous Impulses in Relation to Locomotion in the
Earthworm, by John F. Bovard, Pp, 103-134, 14 figures in text. January,

SA Tite alas SRA CaS SES SES SIGS Ss aR 3 pe ce ae Bn es Ie eA Egle ND So Oa 35
8. The Function of the Giant Fibers in Earthworms, by John F. Bovard. Pp.

135-144, 1 figure in text. January, 1918 ee OE Se Se ae Se Sao
9. A Rapid Method for the Detection of Protozoan Cysts in Mammalian

Faeces, by William C. Boeck. Pp. 145-149. December, 1917 0000002. .05
10. The Musculature of Heptanchus maculatus, by Pirie Davidson... Pp. 151-170,

+2 Deuresan texts Maren LOLs * son far ny TS ee ee a ge «26

11. The Factors controlling. the Distribution of the Polynoidae of the Pacific
Coast of North America, by Christine Essenberg. Pp. 171-238, plates 6-8,
Bedieures, inifecte Waren, WHOL Gs 2 Sek A SS 75

12. Differentials in Behavior of the Two Generations of Salpa democratica
Relative to the Temperature of the Sea, by Ellis L. Michael. Pp. 239-298,

_ -plates’9-11, 1 figure in‘text:. March, 1918 1220002 .0 nooo ccc 65

13. A Quantitative Analysis of the Molluscan Fauna of San Francisco Bay, by
E. L. Packard. Pp. 299-336, plates 12-13, 6 figs. in text. April, 1918... .40

14, The Neuromotor Apparatus of Huplotes patella, by Harry B. Yocom, Pp.
337-396, plates 14-16. September, 1918 2..o...etco ee ccd ecceee ay / 1

15, The Significance of Skeletal Variations in the Genus Peridinium, by A. L.
Barrows. Pp. 397-478, plates 17-20, 19 figures in text. June, 1918 -........... 90

16. The Subclavian-Vein and its Relations in Elasmobranch Fishes, by J.
Frank Daniel. Pp. 479-484, 2 figures in text. August, 1918 —..u.. 10

17. The Cercaria of the Japanese Blood Fluke, Schistosoma japonicum Kat-
surada, by William W. Cort. Pp. 485-507, 3 figures in text.
18. Notes on the Eggs and Miracidia of the Human Schistosomes, by William
W. Cort. Pp. 509-519, 7 figures in text. ~
ais Nos. 17 and 18 in one cover. January, 1919-222. ccc eee eee 35
30s Index in preparation.

UNIVERSITY OF CALIFORNIA PUBLICATIONS— (Continued)

Vol. 19. 1. Reaction of Various Plankton Animals with Reference to their Diurnal

Migrations, by Calvin O. Esterly. Pp. 1-83. April, 1919 W............

2. The Pteropod Desmopterus pacificus (sp. nov.), by Christine Essenberg. - se

Pp.: 85-88, 2 figures im»text: » May, 1919 uses ce. on ee ect ces scence nngeenncnnseen Sees
3. Studies on Giardia microti, by William C, Boeck. Pp. 85-136, plate 1, 19
MS UTES Ti COR csc a ar a ate ctacoeapecen be eeane ee aaa,
4. A Comparison of the Life Cycle of Crithidia with that of Trypanosoma in
the Invertebrate Host, by Irene McCulloch. Pp, 135-190, plates 2-6, 3
figuras in-text: October; 2019. i ere oe ne ee oacnhes
5, A Muscid Larva of the San Francisco Bay Region which sucks the Blood
of Nestling Birds, by O. E. Plath. Pp. 191-200. February, 1919 ................ us
6, Binary Fission in Collodictyon triciliatum Carter, by Robert Clinton Rhodes,
Pp. 201-274, plates 7-14, 4 figures in text. December, 1919 ......000.i.
7. The Excretory System of a Stylet Cercaria, by William W. Cort. Pp. 275-
281 .aeure in: text: “Aneust IQ) of Se See
8. A New Distome from Rana aurora, by William W. Cort. Pp. 283-298,
bfigures*in text.” November; 1910.2 oo ot ee a ee tard
9. The Occurrence of a Rock-Boring Isopod along the Shore of San Fran-
cisco Bay, California, by Albert L, Barrows. Pp. 299-316, plates 15-17.
Moecemper, TIS as CS, oo a eet eet age ae ae arr
10. A New Morphological Interpretation of the Structure of Noctiluca, and
its Bearing on the Status of the Cystoflagellata (Haeckel), by Charles
A. Kofoid. Pp. 317-334, plate 18, 2 figures in text. February, 1920 ......
11. The Life Cycle of Echinostoma revolutum (Froelich), by John C. Johnson.
Pp. 338-388, plates 19-25, 1 text figure. May, 1920 22.2... eeeeeceeeceeeee

Vol. 20. 1. Studies on the Parasites of the Termites. I. On Streblomastia striz, a
Polymastigote Flagellate with a Linear Plasmodial Phase, by Charles
Atwood Kofoid and Olive Swezy. Pp. 1-20, plates 1-2, 1 figure in text.
S pars Rh pice lel eee olan RP SR Remco aaah oe Me ence we ete aig SR a helene

2, Studies on the Parasites ofthe Termites. II. On Trichomitus termitidis,
a Polymastigote Flagellate with a Highly Developed Neuromotor System,
py Charles Atwood Kofoid and Olive Swezy. Pp. 21-40, plates 3-4, 2
fipures in texts.» Duly, sEO1O ode c2 isaac s oe a een ee sSeep can caemtt ea ep eee oeme ena
8. Studies on the Parasites of the Termites. III. On Trichonympha campanula
Sp. Nov., by Charles Atwood Kofoid and Olive Swezy. Pp. 41-98, plates
5-12, é-fisuresin: text. « July,-1919 : 5 2 oe ee eee be
4. Studies on the Parasites of the Termites. IV. On Leidyopsis sphaerica
gen. nov., sp. nov., by Charles Atwood Kofoid and Olive Swezy. Pp.
99-116, plates 13-14, 1 figure in text. July, 1919-2220... aay
5. On the Morphology and Mitosis of Chilomastix mesnili (Wenyon), a Common
Flagellate of the Human Intestine, by Charles A. Kofoid and Olive Swezy.
Pp. 117-144, plates 15-17, 2 figures in text. April, 1920 W022...
6. A Critical Review of the Nomenclature of Human Intestinal Flagellates,
Cercomonas, Chilomastix, Trichomonas, and Giardia, by Charles A. Kofoid.
Pp. 145-168, 9° figures in text... Tume, 1920 o.oo. ccec cece cgeteeliencceceensceneten

Vol. 21. 1. A Revision of the Microtus californicus Group of Meadow Mice, by Rem-
ington Kellogg. Pp. 1-42, 1 figure in text. December, 1918 —..........2.......

2. Five New Five-toed Kangaroo Rats from California, by Joseph Grinnell.
Pp. 49-47," March, 1910! el aa ee ah wat amak

3. Notes on the Natural History of the Bushy-Tailed Wood Rats of California,
by Joseph Dixon. Pp. 49-74, plates 1-3, 3 figures in text, December, 1919

4, Revision of the Avian Genus Passerella, with Special Reference to the Dis-
tribution and Migration of the Races in California, by H. 8S. Swarth.
Pp. 75-224, plates 4-7, 30 figures im text, 1920 2.2.0.2... tices

, 5. A Study of the California Jumping Mice of the Genus Zapus, by A. Brazier
Howell. Pp. 225-238, 1 text figure. May, 1920 2.20.0... ccc

Vol, 22. 1. A Quantitative and Statistical Study of the Plankton of the San Joaquin
River and its Tributaries in and Near Stockton, California, in 1913,

bi Laie Emory Allen. Pp. 1-292, plates 1-12, 1 text figure. July,

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