The Mycetozoa and some questions which they suggest

THS HT

31 K ED WAX;)

AGN17S F

THE MYCETOZOA.

THE.MYCETOZOA-

AND

SOME QUESTIONS WHICH THEY
SUGGEST

BY
THE/ RIGHT HONOURABLE

SIR EDWARD FRY, D.C.L., LL.D., F.RS., F.L.S.,

AND

AGNES FRY.

IN MINIMIS."

Plin. Nat. His.

KNOWLEDGE" OFFICE, 326, HIGH HOLBORN, W.C.

CONTENTS.

PAGE

Introduction .., ... ... ... ... ... 1

Life-history 3

Swarm Spores ,..^_- 13

Cell Theory ..." 15

Nuclei ; 18

Powers of Protoplasm 20

Motion 20

Negative Geotropism 26

Capturing Food 28

Rejection of Matter 29

Species 30

Classification 33

Fructification 39

Sporangium Walls ... ... ... ... ... 43

Capillitium 44

Opening of the Sporangia 53

Spores 54

Aberrant Forms 54

Exosporese 55

Acrasiese 58

Unicellular Organisms 62

Isomorphism 65

The Individual and the Generation 67

Death and Eeproduction 68

Relations of the Group ... 72

Their Relations in the Swarm Spore Stage 74

Their Eelations in the Plasmodiiun Stage 76

Their Relations in the Sporangium Stage 77

Their Relations Reconsidered 77

Distribution 78

Suggestions on Study 79

Bibliography ... ... ... ... ... ... 81

vi.

WOEDS EXPLAINED.

PAGE

JEthalium

Capillitium 5> ^

Columella

Ectoplasm

Endosporete

Endoplasm

38
Exosporese

Elagellum

Hypothallus

Karyokiuesis

Microcvsts 9

21
Microsomata

Nucleus

Plasmodiocarp

Plasmodium

Protoplast

Sclerotium

Sporangium ••• ,_•••

Sporophore

Swarm Cell

Swarm Spore 8> 13

CONTEXTS.

UENEEA AND OTHEE GEOUPS EEFEEEED
TO.

PAGE

Acrasietc 30,37,58,62

Amcebce „. — 14

Arcyria ... v 10,36,37,39,46,51,53

Badhamia 3,4,5,9,10,29,39,52,54,76

Calcarinese... .... ... ... ... ... ... 50

Caulerpa 63

Ceratomyxa 36,55,56,57,73

Chara 21

Comatriclm 11,15,34,39,42,49

Cribraria 31,32,34,39,43

Crateriun 34,42,51,53

Cutleria 31,32,43

Dictydiuin 43,71

Diet yostelium 36,41,59,62,73

Didymium 8,28

Enertlienerua 47, 51

Floridese ... ... ... ... ... ... ... 74

Foraminifera ... ... ,.. ... ... ... 65

Fuligo 22,24,40

Uemitrickia ... ... 45,46

Hydnum ... 73

Iridese 66

Jungermannia) ... 47

Labiate 35

Lamproderma 43, 47

Liliacero 66

Lycogala 10,23

Marcliantia 27

Mesenterise ... ... 9

Monads 14

Multinuclcatse ... ;.. 63

Vlll. CONTESTS.

PAGE

Mycetozoa 1,36

Myxogastres 1

Myxoinycetes 1, 36

Myxothallophyta 1

Peranosporese ... 74

Phfeosporete 74

Phascum 53

Physaracese 50

Physaruin 44

Perichoena ... 28

Polyporus 73

Polysphondylium 59,60,61

Stemonitis 7,28,38,39,41,42,48,50

Trichia 10,44,46,51,53

Ulva ... 74

Volvox 74

ERRATUM.

PAGE 21. — For " The granules stream in one direction ; then
pause, from sixty to ninety seconds (in the case of healthy
plasinodia) " ; read, " The granules stream in one direction
from sixty to ninety seconds (in the case of healthy plasniodia),
then pause."

NOTE.

The quotation on the Title Page we have attributed to Pliny
in his " Natural History," on the authority of Wordsworth in
his heading to the Vernal Ode. We have not succeeded in
finding it in Pliny himself, but our search has not been
exhaustive.

THE "MYCETOZOA,

And some Questions which they Suggest.

WE are desirous to make known some small
friends of ours to those who are hitherto
unacquainted with them ; but we are embarrassed as to
how to introduce them — by what name to present
them. It is true that they bear several names derived
from the Greek language, Mycetozoa, Myxomycetes,
Myxogastres, Myxothallophyta, but these are not
familiar words. In German these organisms bear a
name which has been translated into English, but it
is so repulsive that we would willingly suppress it if
we could, just as one would not like to introduce a
charming girl to strangers by some name of a distinctly
disagreeable suggestion : —

" A name ? if the party had a voice,
What mortal would be a Bugg by choice ?
As a Hogg, a Grubb, or a Chubb rejoice ? "

And so what beautiful little thing would, if it had a

*

2 The Mycetozoa,) and

voice, be introduced as a "slime fungus"? and yet this
is the only English name of the organisms in question.
Some intimates of these ill-named beings try to get over
the difficulty by inventing pet names, and call them
" myxos," or " myxies," and, on the whole, we incline to
adopt the latter word. It is short, and it rhymes with
pixies.

But what are these myxies ? someone will be impatient
to say. Are they fungi ? No. Are they mosses ? No.
Are they ferns ? No. Are they lichens ? No. At any
rate, plants ? That is doubtful. Then surely they are
animals ? We do not know. They are living things—
and beyond that we will not go for the present.

There is another difficulty in the way of presenting
these organisms to the novice : that their forms and
structure are so far unlike those of plants or animals with
which every one is familiar that we cannot use very well-
known terms in describing them, and we shall have to ask
permission to employ some special terms, when common
ones fail. But we shall endeavour to be as clear as we
can, and to readers who will give us their attention we
believe that we shall overcome these obstacles, and we
believe, too, that a little difficulty in following the exposi-
tion will be more than repaid by the interest of the subject.
It appears to us that many most interesting biological
problems are presented in very simple form by this class
of organisms, and we shall not hesitate to refer to these
from time to time in the following pages.

If our reader will turn over the pages and look at the

Some Questions which they Suggest. 3

illustrations which follow, he will by his eye get a general
notion of the kind of thing about which we are going to
talk.

LIFE-HISTORY. — We propose in the first place to sketch
the life-history of one of these organisms as an example of

FIG. 1. — Badhamia utricularis, showing Sporangia.

all, and then to retrace our steps and dwell a little more
in detail on points of interest which emerge in the con-
sideration of the several stages of its existence.

If our reader will look at Fig. 1, he will see depicted an
organism consisting of a number of bodies somewhat like

B 2

4 The Mycetozoa, and

grapes in shape ; he will see that each little berry is
attached by a tender stalk to a substance which is a piece
of dead wood, and he will notice that these berries are so
grouped together as to suggest the notion of a common
origin. This little organism is known as Badhamia utricu-
laris, the generic name being derived from a Dr. Badham,
a labourer in the field of cryptogamic botany, and the
specific name describing the bladder-like form of the
principal part of the structure. This species is not un-
common, and is to be found on stumps and logs of decaying
wood.

The bladder-shaped vessels which we have spoken of
are the spore cases of the organism, i.e., they are cases in
which the spores are stored, much as seeds are stored in a
seed vessel. They are known as sporangia. We have
chosen to begin with the organism in this form because
it is the most conspicuous, and therefore the most easy
for a beginner to get hold of.

If now a specimen of this Badhamia be placed under the
microscope, it will be seen that the coat of the sporangium
is a delicate shell containing minute granules of lime, and
that the dark appearance of the body is due to the brown
spores which lie beneath the transparent shell. Next if a
sporangium be broken and the contents examined under
the microscope (as shown in Fig. 2), it will be found that
the delicate white shell contains a network of threads,
also white from the lime with which they are charged, and
that they occupy the interior of the sporangium, and pass
from wall to wall much like the cancelli in a long bone.

Some Questions which they Suggest. 5

In addition to these threads there are the small round
spores. In these threads we have come upon a very
characteristic structure in these little organisms ; it is
found in the sporangia of most of them but in very
varying forms, and very diversely arranged, of which we
shall say more hereafter. This system of hairs in the
sporangia is known as the capillitium.

Fia. 2.— Badhamia utricularis, broken Sporangia
showing Capillitium.

As the sporangia contain spores it will be at once under-
stood that we stand on the threshold of a new genera-
tion, and we must now follow the history of the spores.
These, when carefully looked at, are seen to be covered
with minute spines, and thus present a somewhat rough
appearance.

If now the spores be placed under favourable circum-

6 The Mycetozoa^ and

stances, i.e., with sufficient moisture and warmth, small
translucent bits of naked protoplasm will be seen to
emerge from them, leaving a mere shell behind them ;
these bits of protoplasm have a movement of their
own in the water, and can be seen both to shake
themselves, and to move forwards ; they push out a part of
their protoplasm as a whip or flagellum at one end of the
body, swimming with this in front of them, the whip
having a sort of lashing movement. Fig. 3 exhibits
some of these bits of protoplasm. Their motions are
particularly amusing to watch; they swim, they wriggle,
they revolve, they shake themselves, they are full of
life and motion ; they seem at once wilful and purposeless ;
they gambol with one another, and their frolics remind
one of young lambs in spring. They are capable not
only of motion but of digestion, and of the capture of food
in a manner to be hereafter described. These little pieces
of protoplasm bear several names, and as the variety of
phraseology is apt to puzzle students, we pause to say
that they are called sometimes swarm spores, or swarm
cells, sometimes zoospores, and as individual pieces of
protoplasm they are sometimes called protoplasts. The
spore of a moss, or of a fern, is a small structure, endowed
with no power of motion ; these swarm spores, as we have
seen, have a power of motion ; the spore of the moss, or
the fern, is capable by itself of reproducing the plant from
which it has come, but these swarm spores are only repro-
ductive after fusion with others, as we shall hereafter see.
The name swarm cell is likely to mislead, because the

Some Questions which they Suggest.

X 1200

FIG. 3.

1.— Swarm Spore of Stemonitis fusca of the usual form when
8^ imming. n. Nucleus ; v. Vacuoles.

2. — Swarm Spore with three Bacilli adhering to expanded posterior
extremity.

3. — A Swarm Spore with delicate pseudopodia, to one of which
a Bacillus is attached.

4. — The same Swarm Spore. The Bacillus in the act of being
drawn in and partly invested with a tube-like extension of the body
surface.

5.— The same Bacillus contained in a long vacuole, and bulging
out the sides of the Swarm Spore.

6. — The same Bacillus bent double after violent jerking move-
ment of the Swarm Spore.

(From Journ. Linn. Society, Botany, Yol. 25, p. 440, by permission
of the Linnean Society and Mr. Lister.)

8 The Mycetozoa, and

thing so called is protoplasm without any containing
wall, and therefore does not answer to the notion of a cell
as it exists in a beehive or in a police station. We shall
therefore speak of them as swarm spores, though even
that name seems to us to he far from felicitous.

The next step in the life of these swarm spores is that

FIG. 4. — Streaming plasmodium of Didymivm leucopus.
(After Cienkowski.)

they rapidly increase by bi-partition, i.e., splitting into two
parts. An occasional phenomenon here sometimes inter-
venes. At times the swarm spores assume a globular form,
and become covered with a hard coating, and in that

Some Questions which they Suggest. 9

condition are known as Microcysts. But from the wall of
thia cyst the contents afterwards escape, and renew their
movements.

The swarm spores (whether after encystment or not) now
enter upon a new stage. They gather together and fuse
into masses of naked protoplasm, the swarm spores
losing their individuality in a common mass. This mass
is called a plasmodium. This plasmodium grows in bulk
by the digestion of food, such as bits of fungus or dead
wood, and attracts to, and unites with itself, other
smaller plasmodia of the same species. In the Badhamia
utricularis this plasmodium is yellow ; it is white in many
species ; green or orange, or red or grey in other kinds.
This plasmodium moves, sometimes through the substances
of dead wood, in other cases on the surface, expanding in
an irregular fan shape, and marked irregularly by streaks
or veins, as may be seen in Fig. 4. It appears to move in
search of its requisite food. The Badhamia is much
devoted to fungi, and will extend itself over the surface of
a fungus till it has devoured all its more delicate parts.

In the substance of this plasmodium there arises a strong
alternate movement of the more fluid protoplasm, a rush
of circulation through the channels of the plasmodium.
The granules move for a short time in the one direction,
then pause, and then move in the opposite way. The
strongest currents are indicated in Fig. 4 by the letters st.

The plasmodia of different species differ much as regards
size. In some genera they are very visible, and were
known to some of the older botanists as Mesenterias, and

io The Mycetozoa, and

were believed to be a species of fungus. In some cases
they can only be discovered by the microscope ; and,
haunting the interstices of dead wood, they are rarely
visible. Such are the plasmodia of Lycogala, Arcyria, and
of some species of Trichia.

Here, again, a phenomenon of encystment sometimes
occurs. During drought the plasmodium may become
quite dry and hard without losing vitality. In this stage
the hard plasmodium bears the name of sclerotium. That
of the Badhamia is quite horny, and orange-red in colour.
On being wetted it will resume its old plasmodium form,
and move as before.

This conversion from an active into a passive condition
of the plasmodium seems to be brought about by two con-
ditions— the want of moisture and the want of food. This
last fact is illustrated by a case in which a plasmodium
placed on wet cotton wool, but without food, was found to
turn into a sclerotium. The capacity for rest and awaken-
ing is thus a protective one, and enables the organism to
tide over a time of famine or drought. It is certainly a
better plan even than the Lydian practice of playing games
to forget hunger.

From the plasmodium stage, whether broken into by a
sclerotium condition or not, the organism, after a time,
prepares for its next effort. It seeks some spot, on the
surface of dead wood or leaves, sometimes a rather exposed
and elevated position, at other times a sheltered one, and
there forms sporangia, so that what before was a mass of
more or less amorphous protoplasm has differentiated itself

Some Questions which they Suggest. n

into several parts, into delicate pedicels, the coating mem-
brane of the sporangia, the hairs of the capillitium, and the
spores — which in due time are to begin again the circuit
of the life-history of the Badhamia, which is in all essen-
tial features that of the whole group of myxies. The
sporangia in the course of their development sometimes
undergo a great change in colour ; for instance, the young
sporangia of Comatricha are an ivory white, and they
gradually change into a glossy black ; and the groups of
little tree-like growths with their developing forms and
varying colours, all gathered together within a few square
inches, is a sight of great beauty. In the maturity of this
sporangium stage of the organism it has lost all its powers
of locomotion, it has lost its powers for digestion, and in
its stationary condition devotes its energies to the
reproduction of the species. The motion of the granules
of the protoplasm continues to some extent until the forma-
tion of the spores.

Now, pausing here for a moment, and taking merely the
outline of the facts as we have drawn it, we have surely
abundance of matter for thought and surprise. Some
seventy years ago, Fries, one of the first naturalists who
grasped the series of changes through which these organisms
pass, compared these changes to the metamorphoses of
insects. We get, too, an inkling of the difficulty which
naturalists have felt in assigning the myxies either to the
animal or the vegetable kingdom : their locomotion and
rapacious youth seem to shut them out from the plants ;
their stationary condition and their production of sporangia
from the animal world.

12 The Mycetozoa, and

The life-history of our organism may be briefly
summarized in the following diagram, hi which the circle
shows the essential stages of life, and the outliers show
occasional and non-essential stages.

We wish to dwell a little more on some of the points of

interest which arise from the brief narrative we have
given, and from other facts which may be brought in
relation to it, and in doing so, we shall find it best to
consider the life-history of the organism in a different
order from that previously used. We started with the
sporangium, as the most easily grasped and the best known
stage of life ; but we shall now ask you to consider the
life-history bypassing from the simpler to the more complex

Some Questions which they Suggest. 13

SWAKM SPORES.— And first let us revert to the swarm
spores, those little bits of mere translucent protoplasm
which escape from the spores of the myxie (Fig. 3) , leaving
the shells of the spores, from which they have emerged,
behind, as in like manner the spores leave behind them
the membrane of the sporangium. We have seen that in
some cases the myxies form a membrane or coat — as in
the sporangium, the spores, the microcysts, and the
sclerotium ; and it is probable that this membrane is in
some, though comparatively few, cases of the same or a
similar nature to the material of cell walls in the higher
plants, i.e., is formed of cellulose. But what is to be noted
is this, that these membranes are used only as protections ;
they are allowed no part or lot in the vital actions of the
organism, and, so soon as their protection is no longer
wanted, they are cast off and allowed to perish. It is
evident that the contained protoplast and not the containing
membrane is the dominant partner in the concern.

A swarm spore has been defined as " a mobile, ciliated,
asexual, reproductive cell, destitute of all membrane," or,
in other words, it is a piece of protoplasm without any
covering membrane, which is produced without any sexual
action, and which of itself possesses the powers of motion,
of putting out cilia or hairs, and of joining in the repro-
duction of the species to which it belongs. That all this
should be true of a little bit of jelly is marvellous enough,
and presents some of the mysteries of life in a very simple
and condensed form.

Swarm spores, in the sense of the preceding definition,

14 The Mycetozoa, and

are common in both the great kingdoms of organized life.
There is a whole group of protoplasts which, under the
name of Monads, are reckoned to belong to the animal
kingdom ; there is the group of somewhat larger organisms
known as " AmoeboB " — a group of which a suspicion has
sometimes been entertained that they are an immature form
of other organisms ; there are the white particles of the
blood which are almost, if not quite undistinguishable
from Amcebce ; there are the swarm spores, whether
belonging to the Algae, the Fungi, or the Myxomycetes; in
all these cases the protoplasts are of the same kind,
endowed with nuclei and vacuoles, capable of putting out
cilia, and endowed with the power of motion and assimila-
tion. To all appearances there is no essential difference
between them, and yet, in point of fact, they are organisms
as distinct as possible from one another hi their nature and
their future careers.

One thing marks off the swarm spores of the myxies
from all other swarm spores which reproduce the organism ;
they are reproductive only in conjunction. The swarm
spore of an alga is capable by itself of reproducing an alga ;
in the myxies, on the other hand, the swarm spores only
reproduce when they have merged with their fellows and
formed a plasmodium. This phenomenon of the union of
a large number of individual swarm spores into a new and
larger individual which carries forward the course of life
is unique in the myxies, and distinguishes them broadly
from all other known organisms.

In all cases in which reproduction depends on swarm

Some Questions which they Suggest. 15

spores it seems essential that there should be water
enough for the swarm spores to live and move about in ;
and, in the case of myxies, to enable them also by their
movements to join together into a plasmodium. Nothing
is known of their reproduction except in water.

It would at first sight appear that this condition of
their reproductive activity cannot be otherwise than in-
convenient and restrictive, especially in the case of such
myxies as, e.g., the Comatrichas, which often produce their
sporangia on the upper sides of wood, or on the tops or
sides of wooden posts. .But it is probable that a very little
moisture is enough, and that in a shower of rain, or in a
morning's dew, they find sufficient water for the swarm
spores to live and unite. But we confess that the point
seems to us to require further attention.

Water being the medium in which most of the lowest
organisms exist, it is generally thought that the doctrine
of evolution involves this — that the earth has been peopled
by migrations from the water : and the migrations ol
amphibious animals from the one element to the other,
have been dwelt on as assisting us to understand such
migration. In this connection the cases of the myxies
and of the mosses, and no doubt of other mainly terrestrial
organisms which need water as a necessary condition to
fertilization, are worthy of note. One of the most important
functions of life still depends on the presence of the original
medium of their lives.

CELL THEOBY. — The swarm spore is, as we have said,
a bit of naked protoplasm ; so is the plasmodium. Let us

1 6 The Mycetozoa, and

consider briefly what is meant by the expression naked
protoplasm.

When in the seventeenth century the microscope was
applied to vegetable tissues, especially by our countrymen
Hooke and Grew, and by the Italian Malphigi, they were
struck with the presence of small walled cavities in the fleshy
parts of plants. These Hooke called cells, and Grew and
Malphigi utricles or bladders. Hooke' s name has stuck to
them, and plays a great part in botanical writings from
his day to the present. We are accustomed to regard the
cell division as the determining factor in growth, the mode
of division providing, as it were, the form which the plant
is to assume : and especially since the days of Schleiden
and Schwann — when the cell came to be regarded as the
structural unit in the growth of plants — the tracing of
cell development, and the structure of the parts of the cell
(especially the cell walls), and the behaviour of the cell, have
been studied with the utmost care. Presently it came to be
seen that the cell walls were inert and by no means the most
important part of the structure, but that the slimy contents
of the little box, which had been treated with scant atten-
tion in the earlier stages of study, were, after all, the most
remarkable part of the cell, and were to all appearance the
basis of both animal and vegetable life. When attention
was first called definitely to it in the vegetable kingdom it
was termed protoplasm, by Mohl ; when first accurately
observed in animals it was named sarcode by Dujardin ;
and by-and-by it was found that protoplasm and sarcode
were one and the same thing. Then instances were

Some Questions which they Suggest. 17

found in which small masses of protoplasm lived and
moved without any cell walls at all, but so firmly
was the notion of the cell rooted in the minds of many
physiologists, that these naked pieces of protoplasm
have often been called naked cells, a most confusing term
as it seems to us, for it is like calling a man with nothing on
" a naked great coat." Another name, and a much more
convenient one, is protoplast.

The accepted cell theory received something like a shock
when the life-history of the myxies came to be carefully
studied. " All the phenomena," said Cienkowski, in the
year 1863, " which are observed in plasmodia are calculated
to force the observer from the accustomed path of safety
to those of doubt. The fundamental conception of morpho-
logical investigation of the cell leaves us wholly in the lurch
in the case of plasmodia. Neither cell membrane, nor
nucleus, nor other histological elements can be established
in this case by the most benevolent interpretation of the
facts, and, twist the cell theory as we may, it certainly
cannot be fitted to the naked flowing protoplasm of the
Myxomycetes." Nuclei, however, have since been found in
plasmodia.

The cell walls of ordinary plants are composed of a
peculiar substance known as cellulose, and within these
the protoplasm of the cell is contained, with all that may be
contained in the protoplasm — the nuclei, the chlorophyll, the
colouring, and the oily matter, &c. The cell is thus a highly
organized unit, and it is, moreover, capable of carrying on
most marvellous operations, physical and chemical.

1 8 The Mycetozoa, and

An organism which commences life in the simple form
of a piece of protoplasm, in many cases produces cell walls
and rests in these, and thus builds a home for itself in
which it lives and labours. But in the case of the
Myxomycetes this does not occur, or occurs only very
exceptionally, and all the actions which these organisms
perform, and all the beautiful forms which they assume,
are reached without ever forming a cell wall or constituting
a true cell, except in the spore itself. In these actions and
in these forms we see the capacities of simple and naked
protoplasm. The extreme simplicity of the mechanism
seems to bring to the mind more powerfully the inherent
powers of the worker.

NUCLEI. — In the history of the theory of cells it was early
discovered that there is in each cell a smaller structure called
the nucleus, which was originally supposed to be a vesicle
in the cell, but has been now ascertained to be a portion of
a special substance distinct from protoplasm. The nucleus
has been found to exercise something like a dominant
influence on the destiny of the cell — " all the formative
and nutritive processes seem to be dependent upon it,"
and, moreover, it plays an important part in each process
of cell division — i.e., in some or all cases of the division
of the cell the nucleus undergoes a like division. This
division occurs in three ways, of which two only need
now be noticed. One of these modes of division is very
simple. The nucleus gets constricted in the middle, the
connecting link grows slighter and slighter, and breaks,
and we have two nuclei where before we had one.

Some Questions which they Suggest. 19

The other method by which nuclei divide is a highly
complicated and remarkable process, known often by the
long name of Karyokinesis — i.e., the movement of the
kernel. In this process certain polar bodies appear, round
which the constituents of the cell gather, and the nucleus
assumes a curious spindle-like shape before the division
actually occurs.

Now, in the myxies, we have, as we know, no true cells
with cell walls, except, perhaps, in the spores themselves,
but we have protoplasts, in the form of swarm spores, pro-
vided with nuclei, as shown in Fig. 3. In the plasmodium,
too, we have nuclei, and it has been supposed that the
original number of nuclei in the plasmodium corresponded
with the number of the constituent protoplasts, but it has
been shown that the nuclei increase vastly in number, and
that this division and multiplication of nuclei takes place
in all the stages of the swarm cells, of the plasmodium and
of the sporangium. The question whether this multiplica-
tion of nuclei in the myxies at the various stages takes
place by simple division or by the complicated process of
Karyokinesis is one which has been carefully investigated,
although the results can hardly as yet be considered as
conclusive. They appear to be, first, that Karyokinesis
is the method pursued in the swarm spores when they
divide, and again at a later stage in the sporangium shortly
before the formation of spores; and, secondly, that the
multiplication of nuclei in the plasmodium is sometimes
accomplished by Karyokinesis, but probably, also, by direct
division.

20 The Mycetozoa, and

POWEKS OF PROTOPLASM. — What are the powers with
which the simple naked protoplasm of the Myxomycetes
is found to be endowed ? It is endowed with —

(a) The power of motion ;

(6) The power of seizing and digesting food ;

(c) A capacity for excreting what is not suited for

retention by the organism ;

(d) A capacity to perform chemical work ;

( e) A capacity to assume and change colour ;

(/) The power of attracting and being attracted by
and uniting with other protoplasm of the same
species ;
(g) A converse power of avoiding the protoplasm of

other species ;
(/(.) A power to assume a definite external shape, and

to divide into spores and non-spores ;
(i) A capacity to enter into a state of suspended

vitality.

" Life never can arise out of or depend on organization,"
wrote John Hunter; and unless naked protoplasm be
regarded as organized, his remark seems to be verified
and proved past dispute.

Let us consider some of these faculties more in detail.
MOTION. — The motions exhibited by the protoplasm of
myxies are of the most varied kind. We have already
mentioned the jumping motion of the swarm spores and
the crawling action of the plasmodium : now we will ask our
readers to turn again to Fig. 4, and to allow us to describe
what is seen in a crawling plasmodium under a microscope.

Some Questions which they Suggest. 21

The plasmodium is differentiated into two parts: the
larger and interior part contains minute oil granules, or
microsomata ; the external layer is free from granules, and
is perfectly transparent like glass or water. The darker
and granular interior protoplasm is known as the endoplasm;
the hyaline superficial layer is known as the ectoplasm.
Fig. 4 is on too small a scale to exhibit this difference
distinctly.

There are two motions here to be observed, though they
are not disconnected with one another : first, the pulsating
motion of currents of protoplasm ; and, secondly, the
advance of the entire mass of protoplasm.

Under a microscope currents are seen to be established
in the endoplasm, generally up or down the lines of advance
of the plasmodium ; the letters st in Fig. 4 indicate some
of these currents. The granules stream in one direction ;
then pause, from sixty to ninety seconds (in the case of
healthy plasmodia) ; then the current turns and streams
in the opposite direction. These streams sometimes unite
and sometimes divide. It is familiar that protoplasm when
enclosed in cells often exhibits movements, as in the well-
known case of the Chara, but then the movements are
naturally constrained by the cell walls ; in the free
protoplasm of the myxies no such restraint exists.

If the peripheral edge of an advancing plasmodium be
examined, there will be found in advance of the granular
endoplasm a strip of the colourless and perfectly transparent
ectoplasm, of which we have already spoken ; it runs like
the foreshore along the coast of the body. Into this from

22 The Mycetozoa, and

time to time a granule will be seen to advance, and then
another granule, and so on till the line of the land has
been pushed out into the foreshore, and the foreshore itself
is moved forward into the sea. In this way the front line
of the whole plasmodium advances, and as the rear of the
plasmodium is drawn back in the line of advance as the
front line is pushed forward, the whole body of the plas-
modium gradually changes its place and moves forward.

It is a very striking thing to watch these forward move-
ments of the granules. You seem to see in a minute and
most intimate form the locomotion of living things ; and,
moreover, you perceive an internal movement of part,
resulting in a movement in space of the whole organism.
Mr. Spencer has said that " we have as yet no clue to the
mode in which molecular movement is transformed into
the movement of masses in animals." Does not the
motion which we have described offer, if not a clue, yet a
visible example of such transformation ? Be this as it
may, the mystery of motion remains just the same ; there
is the same antinomy between sense and reason — the one
says that there is motion, the other that it is impossible.

" Io dird cosa incredibile e yera."

It must not be supposed that it is only on the surface of
dead wood or leaves that the plasmodia of myxies move.
Sometimes, and especially under the influence of cold,
they retreat downwards, and the Fuligo, a species which
lives on tan and is known as the flowers of tan, will,
under this influence, disappear from the surface of a heap
and retire to the bottom of it. Cold or other unsuitable

Some Questions which they Suggest. 23

conditions seem to cause them sometimes to retreat into
the wood to appear again under more favourable circum-
stances. Some plasmodia inhabit the interior of dead
wood, and only appear on the surface for the purpose of
fruiting : in the search for a suitable home for reproduction
it has been thought that they move away from damper to
drier spots, and they certainly often produce their sporangia
inthe dry air and in high positions. It has been thought also
that light has a tendency to make the plasmodia ascend
and darkness to descend. Sometimes a plasmodium will
ascend a tree or a post for a foot or more, and a species
known as Lycogala epidendron is said always to affect the
highest point of the substance on which it rests. It is
by no means infrequent for plasmodia to leave the dead
wood on which they have been living and to ascend the
stalks of flowering plants, or to spread over mosses, and
often we have been surprised at the distances travelled by
plasmodia in a few hours. The appearance, we may
remark in passing, presented by the sporangia of delicate
myxies on the leaves of mosses or blades of grass is
sometimes very beautiful.

Plasmodia, as we have said, sometimes move in an
upward, sometimes in a downward direction ; in a seed,
as we know, these two tendencies are separated, and the
radicle tends to grow in the direction of gravity, and the
plumule against it ; in the myxies it would seem as if the
same protoplasm at one time had the one tendency, and at
another time the other. Perhaps, in passing, we may
observe that the fact that plants and trees for the most

24 The Mycetozoa, and

part grow upward — i.e., against the force of gravity — is one
worth a good deal of thinking about, and when we look at
the mass of fluid and solid matter raised every year,
especially in the springtime, against the constant operation
of the force of gravity, we get a notion of the magnitude
of a force exerted by plants, to which we can assign no
other origin than life, and give no other name than that
of a living force.

It has been found with regard to the plasmodium of the
flowers of tan that it has a curious tendency to move
against the flow of water ; thus, if one end of a piece of
filter paper be placed in a vessel filled with water and the
other on the table, so that the water flows downward, the
Fuligo will move up the paper, and if the paper be so
arranged that the water shall move up the paper, the
Fuligo will move down.

Some observers believe that the myxie takes only such
food as comes in its way ; Mr. Lister believes that it uses its
vibrating cilia to detect food ; whilst others think they have
observed that food exercises an attraction on plasmodia
and influences their movements ; thus, to return to the
flowers of tan, a piece of tan or of wood steeped in tan has
been seen, according to some observations, to induce the
plasmodium to draw itself towards it, and that without
reference to its position as regards the force of gravity.
There seems no reason to doubt the accuracy of these
observations. Here, then, we see in the primitive form of
naked protoplasm that search after food which exercises
so enormous an influence on the whole animal and vegetable

Some Questions which they Suggest. 25

world as well as in the social affairs of man. How, one
cannot help asking, is the plasmodium made aware .of the
proximity of its appropriate food ? Has it some rudimen-
tary perception — some common sense, of which sight, and
smell, and taste are only more specialized forms ? What
the plasmodium does in the equally near presence of two
equally attractive morsels we do not know ; but we do not
believe that it would starve.

• Sunshine is, again, a condition which seems to exert
an influence on the movements of plasmodia. If a glass,
on which the network of a plasmodium ia spread, be partly
exposed to the sunlight, it hag been observed to withdraw
to the shaded parts, and yet when the time comes for
the sporangia to be produced it would seem in some species
as if there was a movement towards surfaces exposed to
light. But, according to the observations of Mr. Lister,
light apart from direct sunshine does not affect the
movements of plasmodia.

The plasmodium has been found to be sensitive not
only to sunlight, to dampness and dryness, to heat and
cold, but to the influence of chemical substances : the
weak solutions of some chemicals having been observed to
render it more fluid, whilst stronger solutions of the same
substances have made it contract or perish in parts. This
sensitiveness on the part of the plasmodia to so many
influences must, it would appear, render very delicate the
conditions under which alone myxies can succeed in the
struggle for existence. Furthermore, it would appear that
in the selection of places for the production of the sporangia

26 The Mycetozoa, and

they have to select situations affording enough atmospheric
exposure to ripen the spores, and enough moisture to enable
the swarm spores to swim and move about, and it is no
doubt due to the width of the dispersal of the spores that
they find these situations, which are, one would suppose,
comparatively few. It is probably from this delicacy of
the requisite conditions for success that plasmodia are not
unfrequently seen to fail in the struggle of life. They will
sometimes reach the surface, and commence the formation
of the sporangium walls and spores, and then fog off and
decay, without ever reaching maturity or producing sound
spores.

The observations with regard to the influence of heat,
drought, light, and darkness, on plasmodia may be correct,
but it does not follow from them that the needs of the
organism dependent on the stage it has reached, or on
other circumstances unknown to us, may not also operate
on their motions. We know that the sporangia are pro-
duced on the surface, but we hardly know whether the
organism seeks the surface when it is time to develop
sporangia, or develops sporangia when it reaches the
surface.

NEGATIVE GEOTROPISM. —It is not only in the motion of
the plasmodium as a whole, but in the motion of its parts
when it develops sporangia, that we observe an upward
movement. Sometimes, no doubt, the sporangia are
developed on the under surface or the side of the wood on
which they grow. We are inclined to think that different
species prefer different situations for the production of

Some Questions which they Suggest. 27

their sporangia, and that no one law is applicable to them
all ; but in all cases the sporangia appear to stand vertically
to the plane on which they grow.

If we examine the trunk of an oak, we find an elaborate
structure of hard parts which maintains the tree in its
upward growth, and by the force of cohesion resists and
overcomes the force of gravity drawing it downwards.
If we examine the stalk of even a delicate flowering
plant, we find that it is constituted of cells, and that the
cell walls, as well as the fibres, afford to the stem a
certain amount of support ; but in the naked protoplasm of
the myxie we have no woody tissue, no cell wall, and yet
this, too, lifts itself away from the earth and towards the
sun and the air. We then see that the upward motion of
plants does not depend on cell walls, but is an inherent, an
original capacity of some protoplasm.

We can easily appreciate the advantage which this
upward tendency gains for the organism, for it lifts it into
the air and exposes it to the influence of light. We know
the great results on the surface of the earth of this so-
called negative geotropism. If all plants had crawled
along the ground like the thallus of Marchantia or the
hyphoa of some fungi, we should have had a keener com-
petition for surface space even than now exists, and we
should have lost the beauty with which the earth's surface
is clothed. In the myxie lifting up its sporangia, we can
see in the small and in its simplest and most primitive
form, the existence of the same power which enables the
sequoia or the eucalyptus to lift themselves to such enormous

28 The Mycefozoa, and

heights above the ground. But of this power, this im-
pulse, this faculty, this gift of resisting the force of gravity,
and the attraction of the earth — what shall we say ? what
account can we give ? We can only keep silence.

CAPTURING FOOD. — The habits of swarm spores in the
pursuit or capture of their food have been very successfully
observed by Mr. Lister. In the case of Perichcena corticalis
he observed a swarm spore with four vacuoles, each stuffed
with from six to eight bacilli ; and in the course of twelve
minutes he saw four bacilli drawn in by the projecting
parts, or pseudopodia of the swarm spore. In the case
of Didymium (or Chondrioderma) di forme, he observed
that the capture of a bacillus is sometimes effected by
pseudopodia. More often, a funnel-shaped aperture was
formed in the posterior part of the swarm spore, and when
a bacillus was unwary enough to enter, it was enclosed by
a folding over of the lips of the funnel. The bacilli thus
captured were seen to dissolve in the vacuoles, but no
refuse matter was observed to be rejected ; probably the
whole bacillus was of absolutely digestible matter. On
another occasion, Mr. Lister observed a swarm spore come
upon a group of motionless bacilli. It spread itself out
so as to cover four of them, and in about two minutes
resumed its former shape, and crept away, carrying two
bacilli in its vacuole. In the case of Stemonitis fusca, he
observed the capture by pseudopodia of a bacillus so large
that when drawn up into the body of the swarm spore it
forced the swarm spore to bulge out on either side. On this
followed a violent jerking motion of the swarm spore, which

Some Questions which they Suggest. 29

frequently occurs after the ingestion of food, and in a few
minutes the bacillus was bent double, and the vacuole
decreased in size. These observations of Mr. Lister seem
to prove that the view of De Bary that the swarm spores
take in nutriment only in a fluid state cannot be upheld.
These processes are depicted in Fig. 3, which is repro-
duced by the permission of the Council of the Linnean
Society and of Mr. Lister.

It is a curious fact that where a plasmodium on its
march meets with a microcyst of its own kind, it has
been observed to commit an act of cannibalism — to treat
it as if a foreign body, and to enclose it in a vacuole,
and then absorb it. Probably the presence of the mem-
brane prevented fusion until it was removed by an act of
digestion.

REJECTION OF MATTER. — Mr. Lister has been equally
successful in observing the method pursued by the plas-
modium in the rejection of undigested matter. He fed,
and I am afraid overfed, the plasmodia of Badhamla
utricularis on thin slices of fungus, and when a plasmodium
had become loaded with food material, many of the large
vacuoles became charged with undigested matter, which
assumed the appearance of a dark ball, and he " repeatedly
saw these vacuoles push out as bubbles to the surface of
the plasmodium and burst, discharging a cloud of refuse,
consisting of fragments of starch and broken fungus
hyphoe, into the water." But when the plasmodium creeps
over glass, he observed the rejected matter, with a certain
amount of plasmodium substance, to be left " on each side

30 The Mycetozoa, and

of the retreating veins, leaving a mass of the network after
the plasmodium has withdrawn."

In other cases rejected matter, particles of starch or
spores of algse, or other things which have been taken up
by the plasmodium, are found thrown aside in the hollow
cavity of the foot of the sporangium, or even amongst the
contents of the sporangium itself.

SPECIES. — That true species exist in the myxies is doubted
by no one who has studied them, and the constancy of many
forms from distant places strongly supports this view. But it
may be permitted to doubt whether the range of variation
possible to one and the same species is yet sufficiently
known to enable us to rely with security upon the whole of
the present classification. In the progeny of a common
parent when under cultivation, great diversities have been
observed in the character of the calcareous walls of the
sporangium, in the thickness of the capillitium, and even
in its presence or absence, in the colour of the sporangium
walls, the capillitium, and even of the plasmodium. Until,
therefore, more species have been subjected to observations
under culture, or more life-histories have been exactly
traced, we must be prepared to regard the specific distinc-
tions as open to revision. Mr. Massie considers that he
has found cases of hybridism in myxies ; but this, perhaps,
requires confirmation.

Whatever be the limits of variation within a species, the
great fact of specific distinction seems to admit of no
doubt, and one of the most interesting faculties of these
pieces of naked protoplasm is the power of knowing

Some Questions which they Suggest. 31

other pieces of protoplasm of their own species from the
apparently similar protoplasm of other species. According
to the concurrent testimony of three of the chief observers
of these organisms, Cienkowski, De Bary, and Lister,
" union never takes place between plasmodia of different
species." "Branches of different plasmodia," says
Cienkowski, " crawl near one another, and mutually
embrace one another, without showing the least trace of
any fusion."

The merging of two protoplasms has been seen under the
microscope. " There appeared to be no mutual attraction
until the two plasmodia were only separated by a distance of
40 p.. When a lobe from one was pushed out towards
its companion, the intervening swarm cells were thrust
aside, and they came into contact; the hyaloplasm
(ectoplasm) of each blended at a single point, and then a
stream of granular matter was seen to pass, then with a
return flow of the streaming in the layer of the two,
the channel was widened, and a gush of its contents
poured into the smaller one, when union was com-
plete and the system of circulation became common to
both."

It may be permissible to adduce another instance of
organisms of a very simple character to illustrate at once
the attractive force of members of one species on their
fellows, and of the capacity for selection which makes
them reject the members of other, though very similar
species. The case we are about to mention relates to two
species of the genus Cutleria, algae of a low type.

32 TJie Mycetozoa, and

To the receptive ova of Cutleria adspersa, Falkenburg
added actively mobile spermatozoids of the nearly allied
species Cutleria multifida ; so like the other species adspersa
that they can only be distinguished by small external
differences. " In this case the spermatozoids, as seen by
the microscope, wandered aimlessly about, and finally died
•without having fertilized the ova of the allied species of
algas. ... A very different result was obtained as soon
as a single fertilizable ovum of the same species was intro-
duced into the vessel containing the spermatozoids. After
a few moments, all the spermatozoids from all sides
gathered around this ovum, even when the latter was
several centimetres distant from the place at which the
latter were chiefly collected."

These instances impress the mind with the fundamental
character of the fact of species ; whether it has arisen from
variation and selection or not, it is a fact that goes down
to the very foundations and rudiments of organic life, and
even there influences the life and habits of the organism.
As we see it in the myxies, it precedes the origination of
the sexual distinction, it precedes any differentiation of
parts or organs, it precedes the development of the cellular
tissue. It may, perhaps, be said to precede the division
into the animal and vegetable kingdoms. The distinction
can exist in small naked bits of protoplasm, and each of
these, indistinguishable in structure as the protoplasts of
some of the species are to any organs or instruments which
we possess, has the power of distinguishing between these
indistinguishable masses, of attracting and being attracted

Some Questions ivhich they Suggest. 33

by those of its own kind, and of remaining indifferent and
neutral towards those of other kinds.

That the pollen of an oak should not act on a daisy
seems to us natural ; that the naked protoplasm of these
minute organisms should be endowed with this selective
capacity does seem very remarkable, and may well make
one pause and think. Is it possible, one inclines to ask,
to feel sure that all the various species of myxies have been
produced from one original form by the force of a natural
selection ? How can the doctrine of the fittest be applied
as between two naked protoplasts, and if applied only to
the later stages of growth, how has it reacted on the earlier
stages ?

CLASSIFICATION. — We now propose to deal with the classi-
fication of these organisms, and this will afford us an
opportunity of describing more in detail some parts of their
structure.

The value of characters for the purposes of generic and
specific distinctions is a subject well worth consideration,
for it often reveals unexpected facts in the correlation of
parts, startling one by dividing organisms which, at
first sight, seem nearly akin. Colour is for the most part
of little value as a distinction in flowering plants, for
we know how widely colour will vary in the same species.
" Color," says Linnaeus, " in eadem specie mire ludit : hinc
in differentia nil valet;" and yet in the pimpernel, the blue
and red forms differing in scarcely any other character are
true and not interchangeable species ; in the algae the
presence of colours other than green is found a funda-

34

The Afycetozoa, and

mental character in their classification, and in like manner
we shall find in the myxies that the colour of the spores
has been found a character of real value.

What is the meaning, some one may ask, of the value
of a character for classificatory purposes ? It means that
the presence of that character affords a safe line of cleavage ;

1

FIG-. 5. — Cribraria aurantiaca x about sixty diameters.

that those plants or animals which are on one side of the
line will be found to agree in other characters — will have
a likeness in many points of that kind which creates what
we call in human beings a family likeness ; whilst those
organisms which stand on the other side of the line will
be found dissimilar from the first family group. For
instance, if we gather the common white dead nettle

Some Questions which they Suggest. 35

and observe its stalk, we shall find that it is four-sided, so
that a section across it is a square. Now this characteristic
might easily be supposed to be one of little consequence,
and yet, in fact, it will be found to be a true and valuable
one, and that all plants with a square stalk and lipped
flowers will be found to have a four-lobed ovary and four
nuts on the bottom of the calyx, and these belong to the
family of the Labiatse. If now, on the other hand, we
count the number of the stamens in plants, and use this
character as the foundation of our classes, we shall break
up this natural family with its square stems, and shall
relegate some genera, such as Salvia, to one class, while the
great mass of the family go to another, and, what is
perhaps worse, these exiled genera find themselves put
into a class together with plants with which they have no
real connection or sympathy— with the Enchanter's
Nightshade and the Duck- weed. This form of the stem
then has a high value as co-existent with a general likeness
of structure ; the number of the stamens may vary in
plants closely akin, and agree in plants widely different,
and therefore has a low systematic value.

The variations of form of our domesticated dogs are
generally held to be of no value even as specific distinctions ;
but the difference of the markings in the spores of myxies
is held by those who have most studied their classification
to be often a safe difference as between two species. It is
only by experience that we can tell the systematic value
of a difference — i.e., by observing how far it is correlated
with other differences of structure or life-history, and

D2

36 The Mycetozoa, and

whether the difference does, or does not, lose itself in a
series of easy gradations between the two extreme forms.
And yet there are some minds whose thoughts so run
along the lines of creative thought that, as if by a happy
intuition, they are able to seize these crucial points which
are of real value, and to reject those that are useless.
Such is the mind of the true naturalist.

Some slight difference exists amongst naturalists as to
the extent to which the group of the Myxomycetes is to be
carried — viz., whether they shall include or exclude a
small group of organisms about to be mentioned, and as to
the way in which the two terms Mycetozoa and Myxomycetes
shall be used in classification. The following table may
be useful as indicating the primary and secondary divisions
of the group, which we shall accept in its widest significa-
tion :—

Example.
'Withagegateplasmodium,

Acrasiece

3

uiciyosieuum.

'Exosporese, "\

(a)

spores
borne ex- j

Ceratomyxa.

Mycetozoa

With a fused plasmo-.

ternally. J

dium, Myxomycetes

Endosporese ^

spores

borne in- j

Arcyna.

|

^ ternally. J

(a) NOTE. — To avoid confusion, it maybe well to state that in the fore-
going table we have followed the classification of De Bary — that Van
Tieghem would write " Myxomycetes " as the name of the whole class
where we have written "Mycetozoa," and would write "Myxomycetes
proprement dits" where we simply write " Myxomycetes " ; and that
Mr. Lister uses ' ' Mycetozoa " for what we have called "Myxomycetes,"
and so excludes the Acrasiece from the Mycetozoa.

Some Questions which they Suggest.

37

Of these classes, it may at once be observed that the
endosporous Myxomycetes are by far the largest, and that
the species at present known of the other groups are very
few in number, and, accordingly, in the sketch which we
have given of the life-history of a myxie we have dealt only
with the changes in an endosporous myxie.

It now becomes needful to call attention to the points in
which the smaller classes differ from the dominant one.

In the ordinary myxie, as we have seen, the swarm
spores effect a true fusion and build up one mass of proto-
plasm. In the Acrasiese, on the contrary, the swarm

spores do not fuse

or coalesce together,
but only aggregate
together, retaining a
power of separating
from and moving on
one another. This is
the first and broadest
division of the group
of organisms. - ^,.^

The next character-
istic which has been
used for the classifica-
tion of the group is the
position of the spores
in the organism. Hitherto we have only mentioned
spores as contained within the sporangium ; but there
are one or perhaps two species very different in many

Fi<J. 6. — Arcyria punicea (cap = capil-
litium ; c =• cup ; p = pedicel) x about
ten diameters.

38 The Mycetozoa, and

ways from the rest of the group, in which the spores are
carried on the outside of the organism. From this
character the whole myxomycetes have been divided into
two classes : the Exosporese, in which the spores are
developed on the outside of the sporopJwre — *'.<?., the part of
the organism which bears the spores ; and the Endosporeae,
in which the spores are generated within the sporangium.

f I

: -S- ' -

FlQ-. 7. — Stemonitis ferruginea. Group of Sporangia,
x about eight diameters.

We propose hereafter to consider somewhat more in
detail the peculiarities of these two sets of aberrant forms ;
but they will be better appreciated after we have dealt w,ith
the larger group. We therefore now turn to the myxies
which carry their spores within the sporangium, and we
shall indicate some of the points of structure of which
use has been made for the purposes of classification.

Some Questions which they Suggest.

39

FRUCTIFICATION.— Perhaps the point of distinction which
first arrests the eye of the student is the variety of form in
which these organisms fructify and bear their spores.

These forms, to which different designations have been
given, may be considered : —

a. The sporangium, a term which is sometimes applied
to the spore-bearing organ in general, has been often
applied in a narrower sense when that organ is well defined

Fia. 8. — Craterium pedunculatum. Group of Sporangia and
Plasmodiocarps. x about 10 diameters.

and symmetrical, such as the grape-like structures of
Badhamia (Fig. 1), the baskets of Cribraria (Fig. 5), or
the elongated forms of Arcyria or Stemonitis (Figs. 6 and 7).
/3. Plasmodiocarp is a term applied to the spore-bearing
part when it is sessile and irregular in form, sometimes
like a cushion, sometimes like a creeping snake or a long

The Mycetozoa, and

tube. It may be said to represent the aggregated plas-
modium which has stayed its onward course, gathered
itself together, covered itself with a coat, and then produced
spores. This form is shown at a, in Fig. 8.

y. ^Ethalium is the name given to that form of fructi-
fication in which a number of separate spore cases exist ;
but where they are so densely packed together, so intricately
coiled, and so freely anastomosing that their individuality
seems to disappear. The
Fuligo septica, the myxie
to which we have
already often alluded as
living on tan, and which
is known as the flowers
of tan (the only instance,
we believe, in which any
one of these organisms
has the slightest claim to
an English name), is
an instance of this
form of fructification. Fig. 9 exhibits a section of the
mature asthalium of Fuligo.

Though it is both possible and convenient thus to
classify the forms assumed by the fructification, it must
not be Supposed that the lines between them are hard and
fast ; on the contrary, there are abundant instances in
which the plasmodiocarp and sporangium forms merge
into one another ; frequently the two forms will co-exist
as the products of one and the same plasmodium.

FlG. S.—Fuligo septica. Section
of mature sethalium. Somewhat
enlarged.

Some Questions which they Suggest.

Thus the beautiful little cups of Craterium will some-
times fail of complete separation, and part of the
plasmodium is content to take the cruder form of a
plasmodiocarp, "as
shown in Fig. 8. Again,
sporangia, which are
sometimes stalked, are
at other times sessile,
and thus differ but little
from a plasmodiocarp.
In the Dictyostelium
(one of the Acrasiese to
behereaftermentioned),
a similar phenomenon
has been observed;
although in the normal
form the production of
spores occurs at the top
of the pedicel, or
column, in some cases
the plasmodium turns
into spores without ever
developing the column
at all.

There appears to be ,,

Fia. IQ.—Stemomtis fusca. Plas-

a considerable difference modium turning into Sporangia. (After

in the way in which the De Bary') EnlarSed-

plasmodium turns into sporangia. In some cases the

plasmodium first separates, and then each separate part

42 The Mycetozoa.) and

forms a sporangium. In other cases the plasmodium
begins its transformation as a whole, and breaks up into
sporangia as the process advances.

Comatricha and Craterium appear to be cases of the
former mode of procedure ; Stemonitis of the second. Thus
in Comatricha the plasmodium emerges in separate centre?,
like small conical hillocks on the wood. These grow
upward, and as they approach maturity the upper part of
the protoplasm draws all the lower part after it, except so
much as goes to form the pedicel and hypothallus, or foot.

In Stemonitis, on the contrary, the plasmodium gathers
itself together in a lump or mass, and first shows signs of
dividing up by the appearance of papillae on the surface ;
then at points corresponding with the papillae, dark-coloured
stems grow upwards in the gelatinous mass. Around
these stems, portions of the adjoining protoplasm gather,
and separate vertically from their neighbouring parts ; and
again, before maturity, the lower portion of the protoplasm
around each column moves upwards, leaving only the
delicate stalk which supports the arborescent sporangium.
Fig. 10 will explain these steps in development.

It would seem as if the sporangium forms were the most
highly developed, and the plasmodiocarp form the more
rudimentary. We suppose that in the matter of advantage
to the organism there must be something to be said for
and against each form, for the plasmodiocarp must expend
less material on perishable walls and stalks, and, on the
other hand, be less open to the atmospheric influences ;
whereas the opposite in each respect must apply to

Some Questions which they Suggest. 43

sporangia. If one of these forms be better than the other,
why does it not universally prevail ? and why do some
individuals of some species halt between the two opinions ?
We certainly do not know. This is one of the many cases
in which it is at least very difficult to see any advantage
gained by the variations of development of an organism.

SPORANGIUM WALLS. — The walls of the sporangium vary
very greatly ; sometimes they consist of a single membrane ;
sometimes of two or even three membranes ; sometimes
they continue till by rupture they let loose the spores ; in
other cases, the whole, or the upper part only, early falls
away and discloses the system of hairs and the spores
within; sometimes, as we shall see, they are furnished
with lime, at other times they are without it.

In Cribraria (Fig. 5) we have a very beautiful form of
sporangium, the wall of the lower half persists and forms
a cup, whilst the upper half in its mature state consists of
a network only of slender threads more or less thickened
at the points where they cross one another.

In Dictydium we have again another very beautiful form
of sporangium — it consists of rays of longitude gathered
together at the pedicel and at the top as their two poles,
with much slighter transverse lines of latitude. The inter-
vening membrane falls away in whole or in part, and
leaves for the sporangium a basket of most delicate net-
work (see Fig. 11).

In some cases the exterior of the sporangium has a most
delicate surface, shining with iridescent colours. The
Lamproderma is a genus with several species distinguished

44

The Mycetozoa, and

by this beautiful peculiarity. Our English species are
very attractive, but they are excelled in brilliance by some
tropical kinds. Of other genera, the Physarum psittacinum
is another species with iridescent sporangia, and derives its
name from its supposed resemblance to the colours of a
parrot.

Fia. 11. — Dictydium umbilicatum. Empty Sporangia,
x about 40 diameters.

CAPILLITIUM. — It is impossible to consider the form of the
sporangium without reference to the capillitium, i.e., the
system of hairs contained within it, and sometimes entering
into union with it as part of its structure. This capillitium is
often of great beauty. It is formed before the spores in the
course of development, and it is probable that it performs a
part in the dispersal of the spores. Sometimes, as in Trichia
(Fig. 12), the hairs lie free amongst the spores. In this
genus the hairs are furnished with spiral thickenings,
which give them very much the appearance of a twisted
cord, and they are hygroscopic, i.e., under the influence of

Some Questions which they Suggest. 45

moisture they twist and twirl and thus separate and dis-
perse the spores. In Trichia the sporangium opens by the
bursting of the upper part of the case, and then the hairs,
covered with the spores, pour out over the remaining part
of the sporangium, so that it appears as if covered by a
piece of delicate fur.

In some cases the hairs have not only a spiral thicken-
ing, but are furnished with projections, bristles or cogs of

Fio. 12.— Elaters and spores of Trichia varia.

varying shapes. In one species, Hemitrichia rubiformis,
the hair is so thickly beset with bristles that under the
microscope it looks like the prickly stem of the bramble,
and hence it derives its specific name. In some genera
the hairs, as well as the spores, are remarkable for their
bright golden yellow colour.

46 The Mycetozoa, and

A connected system is presented by the capillitium of the
beautiful genus Arcyria (Fig. 6). The immature sporan-
gium is a long egg-shaped case standing on a pedicel ; as
it ripens the upper half or two-thirds of the membrane
burst and fall off, leaving the lower part to form a cup (c),
from which is seen to arise a thick web of fibres, almost
like a pillow made of delicate horsehair (cap). These fibres
are elastic, and so soon as the wall of the upper part of
the sporangium gives way they expand to a height and
breadth greatly in excess of the capsule in which they were
contained. There can be little doubt but that these elastic
fibres when mature must exert a great upward and outward
pressure on the walls of the sporangium, and no doubt
they hasten the disappearance of the upper parts of the wall.

In some species the system of hairs remains attached to the
cup, which is the abiding part of the sporangium wall ; in
other species it is attached to the interior of the stalk only by
a few branches, and then it is apt to fall away from its cup.

The likeness between the hairs of the sporangia of the
genera Trichia and Hemitrichia, and of the Junyermanniss
is very close, and the same variety of arrangement is found
in both cases. Both families exhibit elaters marked by
spiral thickenings (see Fig. 12) ; but in the myxies these
thickenings appear to be external, whilst in the Junger-
mannise they are generally, or always, internal. Both
groups show differences in the number of these spiral
thickenings ; they are sometimes single (as in Hemitrichia
Wigandii), or double, and sometimes reach to as many as
six (in Hemitrichia clavata). In both groups the hairs are

Some Questions which they Suggest. 47

sometimes free and lie loose amongst the spores, and, in
other cases, are joined together into a system — a regular
capillitium, attached to the base of the sporangium. The
Jungermannia epiphylla is a good illustration of such a
regular system of hairs. In both groups the hairs or elaters
appear to perform the same duties, of assisting by a pressure
from within in forcing the sporangia open and of dispersing
the spores by means of their hygroscopic activities.

In some sporangia, the most marked feature is a
columella — i.e., a, prolongation of the pedicel, usually forming
a column or a central line through the sporangium, but
sometimes hemispherical and globose. In some genera it
extends to only part of the height of the sporangium;
sometimes to its entire height. A portion of such
columella is seen in Fig. 13. To the columella the system
of hairs is attached in many divers forms and ways. In
Lamproderma the column reaches part of the way up the
sporangium, and from near its summit it gives off a great
mass of hairs spreading in every direction, so as to form a
globe of anastomosing hairs. In Enerthenema the column
is carried to the top of the sporangium, and spreads into a
sort of capital, the top of which is part of the surface of the
sporangium, and here the globe of slightly branching hairs is
attached to the top, and falls down and fills the sporangium.

More complicated and more beautiful forms arise when
the hairs branch out from all along the columella, and
anastomose with one another so as to form a perfect
network. In these cases the whole of the walls of the
sporangium is supported by the ends of the hairs, and is

48 The Mycetozoa, and

usually very fugacious, and soon falls off, leaving a tree-
like structure of delicate branches. The genus Comatricha
shows round or ovoid heads, not unlike the system of
branches of an oak (see Fig. 14). The genus Stemonitis
has taller tree-like growths, which often remind one forcibly

FiGK 13. — Capillitium of Stemonitis fusca.

of a Lombardy poplar. Fig. 7 shows a group of sporangia.
Fig. 18 shows a portion of the capillitium when the spores
have been shaken out.

It is curious thus to see these similar forms assumed by
the mighty trees and by their poor little and very distant
relatives the myxies ; and yet, perhaps, this similarity is
not a mere accident, but the same physiological necessity

Some Questions which they Suggest.

49

has in each case produced the same result. In order that
the leaves and flowers and fruit may be exposed to the
greatest amount of sun and air, and that the fruit may be

Fio. 14.— Pedicels and Capillitia of Comatricha obtusata.

spread far and wide, it must be supposed that the tree-like
form has been assumed. A globe suggests itself as the
most natural form in which a solid mass can obtain an

50 The Mycetozoa, and

extensive exposure to the action of the sun and of the
atmosphere if they operated equally all round. We say
the most natural, as it would result from an equal and
universal outward growth, but for the purpose of exposing
its surface, the globe must be mounted on a stand ; but as
the lower part will be of less value than the top and sides,
because less exposed to the action of the sun, it will be
convenient that the globe form shall be modified : and this
has been sometimes attained by horizontal, sometimes by
vertical expansion. Some such physical necessities seem
to have influenced the shape of trees ; and similar ends
are, we suppose, subserved by the dendroid forms of the
capillitium in Comatricha and Stemonitis. How has the
chasm between the need and the supply been filled up in
these minute organisms or in the stately oak ?

Another fact which creates further varieties in the form
the sporangia is the presence of lime in the capillitium
and in the coats of the sporangium. In this presence of
the carbonate of calcium in the sporangium, a character
has been found for one of the subdivisions of the myxies,
the so-called Calcarinece. In some cases the lime is found
in small grains in the substance of the covering membrane,
in other cases it is found in star-shaped crystals lying on
the outside of the membrane. These are very beautiful
objects, and may both be seen in the family Physaracece.

In some cases the walls of the sporangium alone have
the lime and the capillitium is without it ; in many other
cases the lime is found also in the capillitium, and that in
different forms. We have already in our sketch of the life-

Some Questions which they Suggest. 51

history of Badhamia utricularis described the delicate lime
structure of its sporangium.

Amongst all the delicate forms of the myxies there is
none perhaps more beautiful than that of the genus
Craterium. The sporangium, as the name of the genus is
meant to tell, is goblet-shaped, and the top of the cup is
usually covered with a distinct lid, which rests on the sides
of the cup. In C. pedunculatum the colours sometimes
suggest the notion of a golden cup with a silver lid, and
in this dainty cup is found a capillitium of large white
lime knots, connected by delicate hyaline or yellow threads,
as shown in some of the broken sporangia of Fig. 8.

It has been suggested that the lime is to be regarded
merely as an excretion, a thing of which the organism
desires to be rid in its actively living parts. Be it so or
not, it is evident that the organism sometimes continues
to make this substance subserve the useful purpose of
support.

It is worth while to note the several ways in which the
capillitium appears to be used to attain the same end —the
maturing and disposal of the spores. Sometimes it is the
untwisting of the hygrometric spiral hairs which disperses
them (as in Trichia, Fig. 12) ; sometimes it is the uprising
of the elastic pillow contained in the sporangium (as in
Arcyria, Fig. 6) ; sometimes it is by the spreading branches
of the capillitium that the spores are scattered over a wide
surface, as in Enerthenema; sometimes they are inelastic
and charged with lime, and are then used as beams to
prevent the walls of the sporangium from falling in and so

E2

$2 The Mycetozoa, and

injuring the young spores (as in Badhamia, Fig. 2). This
wealth of plan, this variety of scheme for effecting the
same end, and with the same or nearly the same materials,
is not unfrequently found in the works of Nature. One
might suppose, if Nature were striving to do the one thing
needful with the utmost economy, and in the very best
way, that there would be one, and only one way which was
the cheapest and best, and that this would, on the principle
of the survival of the fittest, be found everywhere to pre-
vail. But this is by no means always the case. Look at
the vast variety of schemes, by which, in orchids, insects
are made to solve the problem of getting the pollen-masses
out of the boxes into which they have been stowed away,
and then of pollinating with them the stigmatic surface.
Or look again at the vast variety of the forms of the peri-
stomes in mosses (all varieties of the same elements and
of the same fundamental idea), and the various ways in
which they operate under the action of moisture. Or take
again the insectivorous plants. Here the problem which
Nature seems to have set herself is this— given a leaf, how
to catch insects ? And this problem has been solved by
the use of different constituent parts of a leaf in almost as
many ways as there are genera of insectivorous plants.
Or, once more, take the case of birds fitted for subaqueous
locomotion. Here the problem seems to have been — given
wings and legs, how to drive the body through the water ?
and this has been solved, as we know, sometimes by using
the wings, sometimes the feet, as paddles, and with a
wealth of variation that is very remarkable. In all these

Some Questions which they Suggest. 53

cases Nature seems not to ask herself what is the single
best way of using the instruments at command, but, given
certain organs, how to attain the end in view with the
greatest amount of variation !

THE OPENING OF THE SPOKANGIA. — In some cases, as
already mentioned, the sporangium opens by an indetermi-
nate rupture, in other cases Nature differentiates it into
two parts, the upper forming sometimes a lid, as in
Craterium, sometimes falling away early, as in Arcyria.
Just the same kind of difference prevails, it will be
remembered, in the mosses, the sporangia of the clay
mosses (Phascum) opening by a decay of their sides, the
sporangia of most of the mosses on the other hand having a
regular dehiscence.

It is a beautiful sight to see through a microscope the
opening of a sporangium of a myxie under the warmth of the
sun. We have watched it in the Trichia fallax; sometimes
there appears a small hole in the membrane towards the
top, which enlarges into a chasm ; sometimes the whole
upper part seems lifted or pushed up. Then the closely-
packed spores begin to start out — one after the other —
falling at varying distances; then the whole surface of the
mass of spores and elaters begins gently to heave and
move, and the elaters sway about like the arms of a polype.
These actions are, we presume, due partly to the elasticity
of the hairs seeking to expand in every direction, and partly
to the unequal thickness of the parts of the elaters and
the consequently unequal action of the heat on the elaters

54 Ihe Mycetozoa.) and

themselves. They curl and twist because they are un-
equally expanded.

SPOKES. — The spore is another part of the structure which
varies much. Spores vary in size ; they vary in colour, some-
times violet or brown, or red or yellow ; they vary in their
surface, sometimes smooth, sometimes spinulous or covered
with warts ; sometimes covered with a kind of network or
furnished with a border or band. All these variations are
used as points of distinction in the classification of the
myxies, and the presence of a dark violet colour in the
species is found, as already mentioned, to be of high
classificatory value.

Another curious point about spores is the tendency in
some of them to gather into groups of a more or less definite
number, whilst others exhibit no such tendency, but remain
single or aggregated without law. The spores of Badhamia
utricularis have a tendency to gather into groups of from
seven to ten, whilst the spores of its nearest congener,
Badhamia hyalina, often congregate in numbers as high
as twenty, and in other closely allied forms the spores are
free. But this character, though generally true, is not
absolutely constant. The spores of B. hyalina are some-
times almost free, and the same tendency to variation has
been observed in other species.

ABERRANT FORMS. — Having thus given some description
of the various parts of the Endosporous Myxies, we shall
now revert to the aberrant forms which have hitherto been
left out of consideration — viz., the Exosporous Myxies
and the Acrasieae, the position of which in the classifica-

Some Questions which they Suggest.

55

tion may be learned by again referring to the table given
in an earlier paragraph.

EXOSPORE^E. — The Exosporese, or Myxies which carry
their spores on the surface and not in the inside of the
sporangium, consist of one genus — Ceratomyxa — and of
two species, or, according to other authorities, of one
species only with one variety. Of this small organism a
drawing will be found in Fig. 15. Its first describer,
Micheli, called it Puccinia
ramosa (in 1729). In 1805
it was called Ceratium
hydnoides by Albertini
and Schweinitz. It was
described as Ceratomyxa
mucida by Schrater in
1889, and, as that name
is adopted by Mr. Lister,
whose works are the most
convenient for the English
reader, we have thought
it best to follow him.
But we have given the synonyms to prevent our readers
from being misled by the puzzling and lamentable variety
of names.

The Ceratomyxa mucida is by no means uncommon on
rotten wood, and might at first sight be mistaken for a
white or pale-coloured fungus. It consists of an aggrega-
tion of finger-like projections from a common base, and
presents somewhat the appearance of a minute piece of

FlG. 15. — Ceratomyxa mucida.
Magnified. (After Famintzin and
Woronin.)

The Mycetozoa, and

white coral. When the surface of these projections is
examined, it is found to be marked off by delicate lines
into polygonal spaces, from the centre of each of which
rises a delicate white stalk, and on the summit of this an
equally delicate and white egg-shaped spore.
The development of this

little organism has
elaborately studied by
two Russian botanists,
and it is sufficiently in-
teresting to demand a few
minutes' attention. Its
plasmodium emerges from
the wood in points about
the size of a pin's head,
and is found to be differ-
entiated into two elements
— (1) a transparent motile
jelly, and (2) an irregular
network of opaque plasma
embedded in the trans-
parent jelly. These two
parts are shown in Fig. 16.
Gradually little promi-
nences are develope d on the
surface of the plasmodium,
and as these grow into the
finger-shaped projections,
the network of opaque
plasma appears just below their surface, the translucent

FlG. 1 6. — Ceratomyxa mucida.
Plasmodium showing superficial
transparent jelly, and opaque
strands. (After Famintzin and
Woronin.)

Some Questions zvhich they Suggest. 57

jelly of the interior passing through the strands of the
network and forming a very thin external coat. The next
step is taken when the strands of this network thicken so
as to occupy nearly the whole surface of the projection
and then break up into polygonal plates, each furnished
with a nucleus ; from each of these plates there grows a
pedicel supporting a ball which is the future spore ; into
this the opaque plasma of the plate passes. This state
of things is shown in Fig. 17. When the spores have
fallen off, the rest of the plant withers and disappears.

Each swarm spore, according to these authors, often
shows amoeboid move-
ments; divides into two V'" ~ ,'U
equal parts, which assume

a cross-like posture in \£>'

their greatest length, the ^ ,;--. j _ ^...^

one lying on the other ; $A i
then each of the two parts T, ' ' ; : \\ £

divides into two other

parts and again each Of _Fl»- W.— Ceratomyza mucida.
Development of Spores x 160.
the four divides into two (After Famintzin and Woronin.)

parts, so that the original

swarm spore is now represented by eight protoplasts all
lying together ; these then separate, develop cilia, and
act as free swarm spores. Fig. 18 represents the eight
protoplasts lying crosswise together, before their final
separation. We are bound to add that this peculiar
process has not been noticed by Mr. and Miss Lister in
their numerous observations on Ceratomyxa, nor by our-

5 8 The Mycetozoa, and

selves in our more limited ones, and the matter appears
therefore to require further enquiry.

ACBASIE*:.— We have already indicated the existence of
a small group of organisms differing from the ordinary
myxies in the fact that the swarm-spores, though they
gather together and act together, never fuse into a single
mass or constitute a true plasmodium.

Three species have been studied and described with
some care, and their history is so curious that we hope
our readers will not weary if we dwell upon it a little.

The swarm spores are like

those of true myxies, and have
the same amoeboid movements,
but without the dancing move-
ment with flagellffi. These
swarm-spores meet and, as if by
common consent, set up a centre

(After Famintziu and they tend, the long arms or
Woronin.)

straggling parts of the original

gathering coming more and more to the central point.

The course of growth in Acrasis granulata (one of
the organisms in question) has been described by Van
Tieghem. When the swarm cells have gathered together,
they touch one another, and form a cellular mass. This
mass grows upwards in a conical shape. The cells of the
axis, somewhat longer than they are broad, assume a
cellular membrane, and constitute a foot, buttressed up by
other cells. The exterior cells move upwards on this foot,

Some Questions which they Suggest.

59

clothe themselves with a cellu-
lar membrane, heap themselves
together at the summit of the
structure, and thus form a
chaplet of spores.

In Dictyostelium mucoroides a
very similar course of growth has
been observed. The mass which
collects at the central point
differentiates itself into a
column, a membraneous veil to
the column, and a residual mass
surrounding the column. As
the column grows upward this
residual mass does the same,
and thus withdrawing its lower
part from the ground it wanders
up the stalk and forms a cap or
crown which turns into spores
without a trace of capillitium.
Fig. 19 shows in section the
nearly adult form of this or-
ganism.

A still more singular history
is presented by a third species,

the Poli/spliondulium violaceum. c> "Remains of Membrane

broken by growth of the
Here the early stages corre- Sporangium. (After ,J3re-

spond with those already de- feld>)

scribed, the plasmodium, or more accurately the pseudo-

19.— Dictyostelium

6o

The Mycetozoa, and

plasmodinm, gathers itself towards a central mass as shown
in Fig. 20 ; the central mass again differentiates itself into
a column and a surrounding mass of protoplasm which
clings round the attenuated central column, as shown

Fia. 20. — Pseudo-plasmodium of Polysphondylium violaceum.
(After Brefeld.) x about 25.

in Fig. 21 ; it then begins to narrow in at intervals
along this column, and breaks up into discontinuous
lengths with intervening nodes, as shown in Fig. 22 (a).

Some Questions which they Suggest.

61

From these discontinuous pieces of protoplasm there are
subsequently developed in the top of the column a
terminal head, and on the successive lower stages of

FIG. 21.— Immature FIG. 22. — Polysphondylium

Sporangium of Poly violaceum. a and * successive

sphondy Hum violaceum. stages in ripening of Sporan-

(After Brefeld.) gium. (After Brefeld.)

62 The Mycetozoa, and

the column, successive whorls of stalka, each carrying a
lateral and smaller head, as shown in Fig. 22 (6) ; each of
these heads finally ripens and breaks up into spores.

The life-history of all these Acrasiece presents many very
curious points ; it seems to bring before us the fact that
separate protoplasts, without ever uniting into a plas-
modium or ever becoming part of a single organism,
may nevertheless acquire as it were the social instinct
and live for the good not of themselves but of the whole
organism, and for that purpose may submit to a divi-
sion of labour ; for whilst some of the protoplasts assume
the function of only supporting their fellows, the others
avail themselves of the support, raise themselves from the
level of their original surface, and devote themselves to the
fucction of reproduction. And, moreover, certain aberrant
and sessile forms of the Dictyostelium seem to show that this
elevation of a portion of the protoplasm is not necessary
to reproduction, though it may well be that the greater
exposure to the ripening influences of the atmosphere and
the sun may render it beneficial to the organism, and so
more than compensate for the withdrawing from the
function of reproduction of a certain part of the protoplasm,
and applying it to the purposes of support alone.

UNICELLUIAB OBGANISMS. — Leaving now the subject of
classification, and of the aberrant forms of myxies, we
return to the principal group. We have already dwelt
upon the fact that the myxies show all their vital powers
and all their capacity for development without the forma-
tion of a true cell-wall, or undergoing division by septa

Some Questions which they Suggest. 63

formed in cells. It seems scarcely possible for organisms
living in the air to attain any considerable size or com-
plexity of form without the support of cell- walls, and
without the formation of vessels which assist the transfer
of nourishment from one part to the other.

But with plants inhabiting the water — a medium of nearly
the same specific gravity as the plant — and drawing their
nourishment directly from this medium, the case is different,
and the possibility of such organisms attaining con-
siderable proportions and complexity of outward form is
shown by a considerable group of Alga, for which there
has recently been formed a class called Multinueleatce,
which includes four orders with considerable differences
amongst themselves, but which all agree in possessing no
cell-walls, and, under ordinary conditions, no septum
dividing one part from the other. Each organism is thus
a single protoplast. These unicellular organisms, as they
are often called, show a capacity for developing a vast
diversity of forms, many of them very beautiful, and many
of them strangely mimetic of the forms of higher plants —
of the mosses, the lycopods, the conifers, the cactus tribe,
and the hymenomycetous fungi. Some of these organisms
reproduce sexually, others asexually ; some attain very
considerable size — as in the genus Caulerpa, a beautiful
form of marine alga. "Nature," says Mr. Geo. Murray,
speaking of Caulerpa, " appears to have executed in the
form of this genus a tour de force in exhibiting the pos-
sibilities of the siphoneous thallus— in showing that it ia
possible for a unicellular organism to display the varied

64 The Mycetozoa, and

beauties of outward form characteristic of highly organised
types, to attain by means of a lattice- work of cross beams
within the cell body that mechanical support effected
by transverse septa and separate differentiated cellular
structures for other alga and for the higher plants."

A consideration of these structures impresses the mind
very forcibly with the vast inherent capacities of proto-
plasm. Nature had two courses open to her, if we may
so speak, as to the mode of dealing with protoplasm-
endowed as it is with its varied capacities — each of
which she has pursued to a certain extent. In the one
course of development the single protoplast has remained
a unit, and has hi this undivided condition performed all
the needful work of the plant. In the other course, the
protoplasm has been broken up into detached parts by the
cell- walls, and thus a division of labour has been brought
about or promoted which has led to the highest results,
and left the unicellular organisms far in the rear. The
former course of development is seen in the myxies, and,
as we have shown, reached a great development both as
regards size, form, and function, in such algae as Caulerpa.
The other course of development is seen of course in
nearly all the other members of the vegetable kingdom,
and reaches its highest results in such vast and complex
organisms as our forest trees.

One other observation naturally arises from the con-
sideration of these unicellular forms. We are wont to
trace the origin of the differentiation of parts — of the
branches and leaves and so forth — to the divisions of the

Some Questions which they Suggest. 65

cell of the growing points in plants. We now see a
differentiation of parts arising without any such cell to
divide, and without any septa to mark off the future organ.
The protoplasm is the master: the cell-walls are its
humble servants, and we have another illustration of how
the contents are apt to rule the containing structure, and
the soft to rule and mould the hard. The divisions of the
cell-walls are a secondary and subordinate phenomenon.

ISOMORPHISM. — We crave our readers' leave to return to
the fact already mentioned, that unicellular organisms
have a tendency to imitate the forms of cellular organisms,
and that whereas we have in the series and chain of cellular
plants such marked outward forms as those of the moss,
the lycopod, the conifer, the cactus, &c., we have in the
chain of unicellular plants very similar outward forms, so
that we seem to have two chains branching off from one
another, with links here and there which closely corre-
spond with one another. This phenomenon is one found
frequently to present itself to the attention of the philo-
sophical systematist, and like all the phenomena of
Nature is well worth pondering. It has been stated very
forcibly by Mr. Brady, in respect to the Foraminifera,
a group of organisms deeply studied by him : — " A
purely artificial classification is ill-adapted to the
conditions presented by a class of organisms like the
Foraminifera, largely made up of groups of which the
modifications run in parallel lines. This ' isomorphism '

exists not merely between a single series

in one of the larger divisions, and a single series in

66 The Mycetozoa, and

another, but often amongst several series, even of the
same family. It not unfrequently happens that a
member of one group presents a greater similarity to
its isomorph in another group with which it has no
relationship than it does to any other member of its
own group. Take a familiar illustration : suppose the
fingers of the two hands to represent the modifications
(species) of two such parallel types of Foraminifera : the
thumb of one hand resembles more closely the thumb of
the other hand than it does any other of the fingers of
its own."

A comparison of the marsupial quadrupeds of Australia
and South America with the placental mammals of the rest
of the world presents another series of these isomorphs.
There are certain Marsupials which seem set over against
the Garni vora, others against the Eodents, and so forth.
Mr. Murray, in his "Geographical Distribution of Mam-
mals," has figured on the same page two animals, one a
small placental mouse, and the other a small marsupial
mouse, and their outward forms are almost indistinguishable ;
and yet the common parent of the two forms must be sought,
according to our present notions of phylogeny, before the
separation of the two great groups of Quadrupeds.

Another instance of isomorphs occurs in the two parallel
groups of the Iridece and the Liliacece. Every one knows
how closely similar in outward appearance are the purple
crocus of the spring and the purple colchicum of the autumn ;
and yet the crocus is more nearly related to the yellow
iris than to the colchicum ; and the colchicum is more

Some Questions which they Suggest. 67

akin to the garlic or the Butchers' broom than to the
crocus.

It seems as if when two lines of development started
from a common point, they sometimes carried in gremio the
necessity of development along the same lines, and the
production of like form at corresponding points in the
divergent courses.

THE INDIVIDUAL AND THE GENERATION. — But it is time
to return from the long digression into which we have
been led by the unicellular plants. If we consider our-
selves or any other higher organism, whether animal or
vegetable, and ask what is the individual and what is the
generation, we feel at first quite able to reply. We know
that the answers to these questions, when we seek to
pursue the enquiry to the bottom, involve other profound
questions, perhaps, insoluble difficulties, but on the surface
the answers are easy.

If now we turn to the myxies and ask what is the
individual, the answer seems attended with no small
difficulty. In the swarm spore stage each separate proto-
plast is the individual ; each is capable of separate motion,
of digestion, and of multiplication. If we turn to the
plasmodium stage, the individual appears to be the entire
plasmodium, built up as it has been by the union of a great
number of protoplasts, and not always the descendants of
the same parents ; if we take the sporangium stage, and
consider especially those cases in which each sporangium
stands on its own hypothallus, separated from the
hypothallus of its neighbours, the sporangium seems to

F2

68 The Mycetozoa, and

represent the individual. The life-circle of the myxie thus
exhibits a curious alternation of individualism and col-
lectivism— an harmonious solution of the problem raised
by the claims of the two principles which are found in
conflict hi other organisms and states of society.

DEATH AND EEPRODUOTION. — We know that of late years,
many interesting theories and questions have been pro-
pounded in relation to the great fact of Death, and that
the entrance of Death into the great chain of organic life
has been watched and studied.

One view, to which Professor Weismann has given
great prominence, is that unicellular organisms possess
an unending duration, or, in other words, that though
susceptible of death by external force — as, e.g., by fire —
there is no natural death, but on the contrary a potential
immortality. He considers death, therefore, to have
come in with the rnulticellular organisms, and to take
place, as he says, " because a worn-out tissue cannot for
ever renew itself, and because a capacity for increase by
means of cell division is not everlasting but finite."

Another view put forward (not by Weismann but by
Gotte) holds that death is always connected with re-
production, and is a consequence of the latter in the
lower animals.

Lastly may be noticed another view, also propounded by
Gotte, that the first form of death is to be found in the
phenomenon known as encystment, which occurs when
an organism which has been alive and exhibiting the
phenomena of motion becomes stationary, develops a cyst

Some Questions which they Suggest. 69

or coat around it, and after a period of rest and suspended
animation again revives when the favouring circumstances
occur.

We thus state some of the views with regard to death
because we think that it will be found that the life-history
of the myxies throws some light upon them.

Let us, however, first make these remarks : that in the
higher organisms we know of death in two forms, the
death of a part cast-off, as when we shed a hair or lose a
tooth, or as when a tree casts off its dead leaves ; and,
secondly, the death which affects the whole organism;
and further that reproduction is in a great majority of the
higher organisms accompanied by the casting off of some
parts of the organism which have been devoted to the
nutrition and protection of the young offspring. In plants
we know how the floral envelopes drop off, and how the seed
vessels are allowed to fall and decay when their duty is
done ; and corresponding phenomena exist in the animal
world.

When the plasmodium of the myxie has differentiated
itself into the hypothallus and the sporangia, and these
have sent forth the spores, how are we to regard the
events which have happened ? Is the true view that a
parent organism has died ; that the empty sporangium
and the stalk, and the capillitium and the hypothallus
which are left behind to decay are the dead body of the
parent, and that the spores represent the new generation ?

If this be the true view, and there seems much probability
in it, then we have clearly before us an unicellular

70 The Mycetozoa, and

organism of the simplest kind, which exhibits the
phenomenon of death, and we cannot say with Weismann
that it is with the multicellular organisms that death for
the first time occurs.

On this assumption it further follows that we have in
the myxies an instance of the close association of death
with reproduction ; and we are reminded of the analogous
cases of the mayfly and the butterfly, which die after
laying their eggs, and of the death of the male bee after
pairing.

The other view of the facts to which we have referred is
that the throwing off of the sporangium and the capillitium,
and the shells of the spores, is not the death of the whole
parent organism, but the partial death only which occurs
when the parts which have become useless are cast off
and allowed to die, and in this view there is in the cycle
of the myxie's life neither death nor generation, but an
everlasting life ; the same protoplasm would be thought
of as going on in an eternal round of life, subject only to
accretions and to losses. True it would be that the shell
of the spore, the coats and foot of the sporangium, and
the capillitium which it contains, have been thrown aside
and perish ; but the residue of the protoplasm seems to
pass- from swarm spores into plasmodium, from plas-
modium to swarm spores, and so on in a perpetual round.
The swarm spores thus appear not as emanations from
the parent but as the parent itself, and the new generation
and the old are but one person (if personality may here
be spoken of). If we think of death we search without

Some Questions which they Suggest. 71

success for the moment of its occurrence, and we look in
vain for the dead body.

Whether of these two views be the more reasonable it
may be hard to decide. However that may be, it is certain
that there are unicellular bodies, such as the Diatoms, in
respect of which Weismann has so forcibly shown that
death cannot be thought of as a normal event. Thus out
of the depths and first rudiments of organic life there
crops up a suggestion of that immortality which is the
hope and aspiration of its very highest members.

Then with regard to encystment. We have seen that
this occurs in two forms in the life-history of the myxies.
We have found that the single swarm spore may be encysted
and is then known as a microcyst, and that from this
condition it may be awakened and recalled to its activity
as a swarm spore, and we have found also that, in the form
of sclerotium, the whole plasmodium may become quite
dry and hard as an aggregation of cysts, and thus be
reduced to a condition of suspended vitality, but from this
also it may be aroused to its former powers of movement
and life as a plasmodium. In neither of these cases
do we find encystment to be associated with death, nor
with reproduction. " The essential characteristic of
encystment," says Weismann, " is a simple process of
rejuvenescence without multiplication."

The length of time during which animation can be sus-
pended in the case of plasmodia is very remarkable. De
Bary found a plasmodium of Didymlwn serpula to move
after seven months' desiccation ; and a case is cited by

72 The Mycetozoct) and

him of- a plasmodium which after twenty-five years'
residence in an herbarium began, after four or five days'
immersion in water, to develop as a beautiful network.

KELATIONS OF THE GKOUP. — The proper position of the
myxies in the world of organized beings is a subject on
which there has been and still is a great difference of
opinion. So profound is the difficulty of the question
whether they are animals or vegetables that one of the
most careful students of their nature has declared that
its solution "depends rather on the general philosophic
position of the observer than on facts."

Those authors who place the myxies in the animal
kingdom have generally attached most importance to the
swarm spore and plasmodium stages of their existence,
and have insisted on their likeness to the protozoa ; the
advocates of their vegetable character have mainly dwelt
on their method of reproduction — on their sporangia and
their spores.

But even assuming them to be vegetables, there remains
the question where they are to take their place in that
realm of Nature. They were placed among the fungi by
Fries, but with a lively consciousness of how entirely they
differed from all the other members of the class. ' ' Vegetatio
maxime singularis et a reliquorum fungorum prorsus
diversa," he says of this group. The fungi seem as a
natural group to be well characterized by a prothallus
constituted of hyphae — generally multicellular — whereas
the myxies are represented in that stage by the strange
plasmodium of which we have said so much.

Some Questions which they Suggest. 73

Attempts have been made to show that different sections
of the myxies correspond with different sections of fungi :
the common myxies being treated as of the G-asteromycetie
type ; the Dictyostelium as of the Mucorine type ; and,
according to some writers, the Cer atomy xa mucida as of
the Hydnum type and the Ceratomyxa porioides of the
Polyporus type ; and from this supposed correspondence
of type it has been suggested as probable that other types
of fungi will be found to be represented amongst myxies,
and that so we shall have two parallel series of fungi ; the
difference in each case being that the one is characterized
by a mycelium of hyphse, and the other by a plasmodium.
This view appears to us to be fanciful, and to slur the
really broad line of distinction between fungi and myxies.
More rational would seem to be the view put forward by
one of the latest writers on classification, who has formed
of these little organisms one of the four primary divisions of
the vegetable kingdom, and made for them a place of equal
rank with the whole of the phanerogamous plants ; so
distinct a position scarcely seems excessive to mark the
singularity of their structure and life-history. In fact,
one of the many interesting points about this group of
organisms is the extent to which they stand alone ; the
difficulty of finding any other creatures to which they
stand in the relation either of descendants or ancestors.
"The mycetozoa," says De Bary, "show only a slight
agreement, either in the general course of their develop-
ment, or in the characteristic features of its separate stages,
with organisms which are of undoubted vegetable origin,

74 The Mycetozoa, and

whether they be fungi or plants other than fungi; the
agreement, with the exception of the few cases in which
cellulose makes its appearance, is common to phenomena
which are common to all organised bodies."

We are much impressed with the notion that the position
of the myxie will be found to vary according as the one or
the other stage of their existence is held to have the
highest classificatory value. We therefore propose to
consider what relations they exhibit in these various stages
of their life-history.

THEIR BELATIONS IN THE SWARM SPORE STAGE. — Bepro-
duction by swarm spores is by no means confined to the
myxies. It plays a conspicuous part in the cycle of life
in many of the Algas and Fungi : or rather we should say
conspicuous parts, for the functions of these simple pieces
of motile protoplasm are most various. Sometimes the
swarm spore is asexual and is of itself capable of repro-
ducing a new organism — as in some of the Algae and in the
PeronosporecB , for instance, amongst the Fungi. In some
of the Algse (Floridea and Phaosporea) the swarm cells
are sexual, and a conjugation between two of these moving
bodies occurs before the production of a new organism.
Sometimes the same organism (as in Ulva) produces two
kinds of swarm cells— the megaspores with four cilia which
germinate asexually, and the microspores with two cilia
which germinate only upon conjugation. But more
remarkable still is perhaps the case of the well known and
beautiful Yolvox — which appears to emit no less than four
distinct kinds of swarm spores, (1) sterile swarm spores ;

Some Questions which they Suggest. 75

(2) asexual spores, or as they are called parthenospores ; (3)
male spores ; and (4) female spores. So marvellously
complicated are the modes in which Nature is capable of
differentiating and using to attain the same end by different
roads that which seems the simplest thing in life — a
minute piece of naked protoplasm.

In the swarm-spore state the myxies may thus seem to
claim relationship with the Algas and Fungi, but it ia
doubtful whether much stress can be laid on this sugges-
tion, for (1) the existence of these cells as reproductive
spores is a wide-spread fact, and occurring in remote
groups of organisms, has perhaps but little value in
classification ; and (2) the mode in which myxies reproduce
through swarm spores is entirely different from that pursued
by any Alga or Fungus. It is, as we have already shown,
neither by parthenogenesis of the ordinary kind, nor by
conjugation, but by the fusion of a great number of swarm
spores, whether from the same or different sporangia, into
a single mass of plasmodium.

But if we turn towards the animal kingdom, we shall
find that its claim to include the myxies in the swarm
spore stage is very strong.

A mass of naked protoplasm, furnished with a nucleus
and vacuoles, capable of pushing forward pseudopodia,
and moving by these means, capable of including and
digesting food, and also of encystment — this is a descrip-
tion which will fit indifferently the swarm-spore of a myxie
and the well-known Amseba, and we are thus brought to see
that close relationship, to which we have already referred,

76 The Mycetozoa, and

between the swarm spores and the large group of protozoa
which naturalists generally place in the animal kingdom,
and all of which may be said to consist of undifferentiated
and naked protoplasm.

THEIR KELATIONS IN THE PLASMODIUM STAGE. — The motor
power of the plasmodium seems to recall animal life, but
we recollect that there are kindred organisms, like the
Diatoms, which are generally regarded as vegetable, and
retain a power of movement through life.

As regards food, it is a familiar fact that, generally
speaking, plants feed on inorganic and animals on organic
substances. So far as observations have hitherto gone,
the food of myxies consists of bacteria, or minute particles
of wood or fungi (and, in the case of Badhamia utricularis,
of living fungi). No evidence seems to exist to show that
they have any power of deriving nutriment from inorganic
substances. The mode in which the myxies eject the
undigested matter recalls animal rather than vegetable
life. In the methods of digestion, therefore, they seem to
lean distinctly towards an animal character.

The movement of the granules of protoplasm in the
plasmodium is a phenomenon at least analogous to that
found in plants, and even in plants with highly developed
cells, but it is not unknown amongst the lower forms
which are considered to be animals, for it appears to have
been observed in some protista, and especially in the
tentacular-like pseudopodia.

In the plasmodium condition, the relationship of the

Some Questions which they Suggest. 77

myxies seems on the whole rather with animals than
plants.

THEIR RELATIONS IN THE SPORANGIUM STAGE. — On the
other hand, when we reach the sporangium stage, the
absence of motion, the erect form, the stalk, the foot, the
spores, all recall some of the Fungi ; the elaters remind
us of the Jungermannise.

• The methods of opening the sporangia, sometimes by an
indefinite rupture, sometimes by a distinct operculum,
recall the distinction between the methods of opening
which prevail in the mosses. On the whole, the facies of
the sporangium stage is vegetable.

One other observation which relates to all the stages of
development must be made. The two most characteristic
of vegetable compounds are probably cellulose and
chlorophyll : though neither is found in all plants, nor is
absent from some animals. Of chlorophyll we have no
trace in the myxies, and of cellulose very little. Nowhere
do we find it as the wall of a true and living cell as we do
in the most characteristic form of vegetable growth.

THEIR RELATIONS RECONSIDERED. — On the whole it seems
impossible to assign these minute organisms with any
certainty to the one realm or the other. If, with Haeckel,
we were, for purposes of classification, to speak of a new
kingdom —a buffer state between the animal and vegetable
realms, the Regnum protisticum — we should no doubt
place the myxies there. But, if we retain the two ancient
kingdoms only, then it almost seems as if the myxies were

78 The Mycetozoa^ and

a vagrant tribe that wander sometimes on the one side,
and sometimes on the other side of the border line —
like nomada wandering across the frontier of two settled
and adjoining States, to neither of which they belong.
They would seem to begin life as animals and end it as
vegetables — a life-history not without some sad analogies
in human experience.

The absence of a satisfactory position for the myxies in
the great network of organized beings leads one to think
of them as a group which probably from very remote
antiquity has stood aside from the great currents of
evolution, whether in the animal or the vegetable world.

DISTRIBUTION. — The species at present known of myxies
are not very numerous. Mr. Lister figures less than two
hundred in his monograph ; De Bary speaks of them as
numbering nearly three hundred. No doubt many species
remain to be discovered.

Of the distribution of the myxies in time, nothing is
known. The protoplasm is too delicate to leave its
memorial in the rocks, and its lime particles are so small
and so indistinguishable that it is no wonder that they
have never been traced.

In space, the group, and many individual members of it,
are "cosmopolitan. A large number of the species are, says
Mr. Lister, " found with identically the same characters
in Europe, India, the Cape of Good Hope, Australia, and
North and South America." What is implied in the
identity of a species in Australia and England ? Does it
mean that the species have passed the great intervening

Some Questions which they Suggest. 79

oceans ? or does it mean that the species were defined
before the separation of the continents, and have continued
in both seats unchanged ever since ?

SUGGESTIONS FOE STUDY. — In the hope that some of our
readers may be induced by what we have written to take
up the study of these little organisms, we will say a few
words as to how to begin the study of them. They may
be found often in great abundance, and more or less in all
times of the year, except in extreme cold or prolonged
drought, on moist dead wood and dead leaves (hazel,
holly, and beech leaves are very good) ; a wood yard near a
country house, rotting stumps of trees, the dead stalks of
last year's nettles, the wooden pillars and parts of gates
and rails, the straw heaps in a farmyard — all these are
likely places for the chase. Sometimes, too, as we have
said, they leave the dead substances, which are their chief
habitat, and climb over growing plants, as nettles, peri-
winkles, or moss. The eye wants some training to see
them quickly, and there is no doubt but that young eyes
are better than old ones. We know a case in which a
young lady detected a Trichia growing on the roadside from
her pony's back.

If it be desired to keep specimens for use, they
should be preserved in dry boxes (the common lucifer
match boxes, lined with white paper, make very good
receptacles), into which they can be securely fixed by glue
or pins attached to the wood or leaves on which they rest.
For more minute observations recourse must, of course, be

80 The Mycetozoa, and

had to the pocket lens and the microscope. There are few
more beautiful objects than some of the sporangia under a
low power, or than the capillitium and spores of some kinds
under a higher power : the Trichia with lemon-coloured
hairs and spores are especially lovely to look upon.
The spores should be examined under water to prevent
shrinkage, and a little spirit is often useful in the
examination of the capillitium, as it helps to expel the air.

The beginner will very likely at first sight mistake some
of the small fungi for myxies, but a very little experience
will enable him to distinguish the sporangium walls, the
hairs, and the spores of a myxie from anything which he
will meet with in the structure of a fungus.

A visit to the botanical department of the British
Museum at South Kensington, and an examination of the
microscopic slides and drawings prepared by Mr. Arthur
Lister and his daughter, Miss Gulielma Lister, and pre-
sented by them to the British Museum, will be of great
utility to the student.

To Mr. and Miss Lister all students of myxies are under
the deepest obligations, and we are especially so by reason
of their constant help, and not least for their kindness in
reading this essay in manuscript. Mr. Lister has published
two books which are indispensable to the English student.
The "Guide to the British Mycetozoa exhibited in the
Department of Botany, British Museum," is a little
pamphlet, price threepence, written by Mr. Lister for the
Trustees of the British Museum, and published by them.
It can be obtained at the South Kensington Museum ; but

Some Questions ivhich they Suggest. 81

booksellers are often stupid about getting it, as we believe
that they get no profit on it, and therefore if ordered
through a bookseller particular instructions should be
given to get it from the South Kensington Museum. This
little book is very admirable, and by itself will enable a
student to identify most or all of his specimens. Mr.
Lister's other book, " A Monograph of the Mycetozoa,"
which is not confined to British species, was also published
by the Trustees of the British Museum, but is sold by
Longmans and other booksellers. The price of this book,
which is beautifully illustrated, is sixteen shillings. Mr.
Massee has also published a " Monograph of the Myxo-
gastres," 1892, illustrated with coloured plates. De
Bary's " Comparative Morphology and Fungi, Mycetozoa,
and Bacteria," of which an English translation has been
published by the Clarendon Press, should be consulted by
the student who desires further knowledge. The text-
books on general botany and on general cryptogamic
botany, such as Sach's Text Book, Kerner's " Natural
History of Plants," Bennett and Murray's "Cryptogamic
Botany," and Dr. Scott's " Structural Botany, Part II.,"
may all usefully be consulted.

For the student who desires to go further into the
literature of the subject, the following bibliography may
prove useful : —

CIENKOWSKI. — Zur Entwicklungs-geschichte der Myxomy-
ceten. (Prings. Jahr., 1863, 325) ; Das Plasmodium, id., 400.

LISTEE. — " Notes of the Plasmodium of Badhamia
utricularis and Brefeldia maxima " (Annals of Botany, Vol.

G

82 The Mycetozoa.

II., 1888, pp. 1-24) ; " Notes on Chondrioderma difforme
and other Mycetozoa" (ibid., Vol. IV., 1890, pp. 281-298);
" Notes on the Ingestion of Food-material by the Swarm-
cells of Mycetozoa " (Journ. Linn. Soc., Vol. XXV., Bot.,
1890, pp. 435-441) ; " Notes on Mycetozoa " (Journ. of
Bot., Vol. XXIX., 1891, pp. 257-268); "On the Division
of the Nuclei in the Mycetozoa" (Journ. Linn. Soc., Vol.
XXIX., Bot., 1893, pp. 529-542) ; " Notes on British
Mycetozoa " (Journ. Bot., Vol. XXXIII., 1895, pp. 323-
825) ; " A New Variety of Enteridium olivaceum " (ibid.,
Vol. XXXIV., 1896, pp. 210-212); "On Some Bare
Species of Mycetozoa" (ibid., Vol. XXXV., 1897, pp.
209-218) ; " Notes on Mycetozoa " (ibid., Vol. XXXVII.,
1899, pp. 145-152).

BBEFELD. — Dictyostelium mucoroides Abhand. der Senckb.,
Ges. VII., 1869 ; Untersuchungen aus den Gesammtgebiete
der Mykologie, VI. Heft Myxomyceten (Leip., 1884).

DE BABY. — Die Mycetozoen. Zeitsch., fur Wissench ZooL
(Vol. X., 1860, p. 88).

FAMINTZIN and WORONIN. — Uber Ceratium Hydnoides.
(Mem. Acad. Peter., Vol. XX., No. 3, 1873).

VAN TIEGHEM. — Sur quelques Myxomycetes (Bull. Soc.
Bot.Fr., Vol. XXVII., 1880, p. 317).

WIGAND. — Zur Morphologic und Systematik der Gattungen
Trichia und Arcyria (Pring. Jahrb. Bot., 1863, p. 1).

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Fry, Edward.
Jfy-cetozoa. . .

Fry, Edward
Mycetozoa

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1899

MEDICAL SCIENCES LIBRARY

UNIVERSITY OF CALIFORNIA, IRVINE
IRVINE, CALIFORNIA 92664