THE DANISH

INGOLF-EXPEDITION.

VOL. V, PART 4.

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CONTENTS

OST^tf CARLGREN: ZOANTHARIA.

PUBLISHED AT THE COST OF THE GOVERNMENT

THE DIRECTION OF THE ZOOLOGICAL MUSEUM OF THE UNIVERSITY.

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COPENHAGEN.

H. HAGERUP.

PRINTED BY BIANCO LUNO.

i9<3-

THE DANISH INGOLF-EXPEDITION.

VOLUME V.

4.

ZOANTHARIA.

BY

OSKAR CARLGREN.

WITH 7 PLATES AND 6 FIGURES IN THE TEXT.

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COPENHAGEN.

PRINTED BY BIANCO LUNO.
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nr^HE present paper on the Zoantharia (Zoanthidae) has been drawn np according to the same plan
■*• as my report on the Ceriantharia of the Ingolf-Expedition. Thus, it comprises not only the
Zoantharia collected during the Ingolf-Expedition but also all the other northern and arctic forms of
this group of animals which have been sent to me for examination, especially from the Riksmuseum
in Stockholm but also from the museums in Copenhagen, Upsaia, Bergen, Trondhjem and Tromso.
Besides, I have had the opportunity of examining some forms from the museums in Vienna and
Berlin. To the chiefs of the Invertebrate departments or the custodians of the Coeleuterata at these
museums I would offer my best thanks for having lent me the material required. I am also greatly
indebted to my colleague Docent Nils Holmgren in Stockholm for helping me to photograph the
originals for the figures reproduced on PL 2.
The paper is divided into three parts:

1. Literature and summary of the northern and arctic Zoantharia.

2. Contribution to the systematic classification of Zoantharia (Zoanthidae).

3. Description of the species.

418:

or •

Section I.

Literature and summary of the northern and arctic Zoantharia.

'TpHK first species of Zoantharia (Zoanthidae) described from northern waters was Epizoanthus incru-
A status, which forms colonies and lives symbiotieally with Eupaguridae. This easily known spec-
ies was found on the Norwegian coast by Diiben and Koren, who in 1847 called it Mamillifera
incrustata. M. Sars (1851, i860) and Danielssen (1859) also observed this species from other localities
on the same coast. In the year i860 Sars mentioned a new species from Finmarken, which he
named Zoanthus arcticns and in 1868 Norman described from the Shetland Islands Z. incrustatus and
Z. angnicomns, the latter for the first time. A fourth species found in the Trondhjem Fjord was
described by Koren and Danielssen in 1877 under the name of Zoanthus norvegicus. In the year
1877 Marenzeller mentioned Zoanthus arcticus from the regions round Smith Sound, which however
is identical with Epizoanthus lindahli described later in this paper, and in 1886 (p. 16) the same
author stated, that Palythoa norvegica had been dredged near Jan Mayen, a statement however which
proved to be incorrect, as the specimens on closer examination were found to be identical with or at
any rate closely related to Epizoanthus glacialis, a species described later by Danielssen. The
same year (1886, 15.52) C. Auri villi us put forward a new species E. couchii unknown in the Nor-
wegian fauna, a statement however that could not be maintained, as the species in question is closely
related to Epizoanthus erdmanni of the present work and may possibly even be considered a variety of
the latter species. Thus, up to 1890 4 species of Zoanthidae living at the Norwegian coasts or in
the northern seas, namely, Epizoanthus incrustatus, E. arcticus, E. norvegicus and Parazoanthus
anguicomus, had been described in some detail, though very incompletely.

During the period from i860 — 1880 the well-known naturalist Verrill provided us with
information regarding some Zoanthidae from the coasts of North America. In the year 1864 he
described from New Jersey Zoanthus (Epizoanthus) americauus, which has later been met with very
often in the arctic regions, as far as Cape Cod and also in the region Cape Cod to Cape Hatteras
(Parker 1900, p. 757). In 1891 H add on and Shackleton proved, however, that this species is
identical with Sars' E. incrustatus. In the year 18S2 another species of the North American Zoanthid
fauna became known, namely, Epizoanthus paguriphilus, first observed in deep water off the Nova
Seotian coast; like E. incrustatus this species forms carcinoecia. Further, Verrill mentions an incrusting
variety of E. americanus (1882, p. 316, 1883, p. 6), which he considers to be identical with Koren and

The Ingolf-Expedition. V. 4. I

ZOANTHARIA

Daniels sen's E. norvegicus. In his paper of 1883, PI. 8, fig. 6, an illustration of this variety is
given. Though it is, of course, very difficult to settle the question without being in possession of
the original specimens, if they exist, the variety undoubtedly belongs to a Parazoauthus species.
Yerrill's figure has, namely, a fairly strong resemblance to the colony figured by me on PI. 1, fig. 19,
collected at St. 2245 U. S. F. C. together with the typical E. americanus (incrustatus) and determined
as such, but which on closer examination proved to be a Parazoanthus species and in my opinion no
other than P. anguicomus. Lastly, in the year 1885 Verrill described another carciuom-forming
species, Epizoanthus abyssorum, dredged during the Albatross Expedition in 1884, and mentioned at
the same time a free variety of this species (probably a new species). Though Epizoanthus abyssorum
has evidently a more southerly distribution than the other North American species mentioned, I
prefer to deal with it here for comparison between E. incrustatus and E. paguriphilus. I would point
out, however, that I have had very little material of the North American species at my disposal, this
being the reason why these are not dealt with in greater detail here, as also because a further
criticism of the species based on the literature is fairly unremunerative. A revision of the collected
material of the Zoanthidae forms will certainly prove, that the number of Zoanthid species is also 011
this coast not so small as seems to appear from the literature. I have not thought it necessary to
give a complete list of the literature of these three species here. Up to 1891 such a list has in any
case been given for both of the first-named species in Had don and Shackleton's paper (1891).

In the year 1890 the number of known northern and arctic Zoanthidae species was almost
doubled by D an i els sen's description of the material collected during the Norwegian North Atlantic
Expedition. The new species occurring are Epizoanthus roseus, E. arborescens, E. glacialis and
Mardol erdmanni, the last of which was proved by Had don and Shackleton's investigations
(1891) to belong to the genus Epizoanthus. In 1887 (p. 316) Mortensen was of opinion, that he had
found Zoanthus sulcatus and couchii in the Liinfjord, a determination however which must be erroneous
at least as regards the latter, as this species according to Haddon and Shackleton is an Epizoanthus
species, whereas Mortensen's form appeared to belong to a genus Isozoauthus founded by me. Lastly, in
1905 Carlgren mentions from Finmarken, besides E. erdmanni, also Isozoauthus arborescens, for which
he later set up the above-named genus, Isozoanthus, forming a link between the genera Epizoanthus
and Parazoanthus.

Thus, when I began my paper on the northern and arctic Zoanthidae, altogether some ten
species of these had been described previously, many of them, however, very incompletely and mainly
according to the external features. In 1890 Danielssen certainly gives anatomical descriptions of
his new species, but in many respects these are not to be trusted and are of small use for the
identification of the species. Of far greater importance is Haddon and Shackleton's paper on the
British species of Zoanthidae. We find here a good anatomical description, which however in some
respects might have been somewhat more comprehensive. As this is the only efficient work dealing
with the Zoanthidae of the North European coasts, I may refer to it specially, as it also contains an
account of the most important literature on the Zoanthidae up to 1891. Of the species dealt with in
the sequel, however, only E. incrustatus, E. paguriphilus and Parazoanthus anguicomus are described in
detail in the above-named paper.

ZOANTHARIA

Of the species already known the following are described in the present paper.

Epizoanthns incrnstatns, pagnriphilns, abyssornm, glacialis, roseus, norvegicus and erdnianni.

Isozoanthns arborescens and

Parazoanthns anguicomus.

Further, some anatomical details of Parazoanthus dixoni are also given here.

The new species are:

Epizoanthus danielsseni, lindahli, beerenislandicus, koreni.

Isozoanthns bulbosus, danicus, magninsulosus, multinsulosns, davisi, ingolfi, dubius, islandicus.

Parazoanthns haddoni.

All told the descriptions thus comprise 22 species, showing that the northern and arctic
Zoanthid fauna is not so poor as was formerly thought.

In the present paper I do not occupy myself very much with the geographical distribution,
as I shall return to this subject later on when dealing with the Ceriantharia and Actinaria of the
same regions. Along with this I propose to make a more detailed comparison between the Actinian
fauna of the arctic and antarctic waters. It is worth noting, that though the number of known species
from these regions has increased considerably, no representatives of the microcnemic Zoanthidae have
been found there. The occurrence of the new genus Isozoanthns in both of these zones is also
worthy of note, though it is not impossible, that this genus like the genera Epizoanthus and Para-
zoanthus also occurs in the intermediate regions. There seems to be a great difference in the distri-
bution towards the north between the genera Epizoanthus and Isozoanthus on the one side and
Parazoanthus on the other, the latter not being represented in the true arctic fauna, in which both
the first-named occur. Towards the north the genus Parazoanthus seems to be replaced by Isozoan-
thus, of which a decidedly arctic species, I. bulbosus, has been met with so high up as north of Spitz-
bergen at 81° N. Lat, this being the northernmost place of occurrence of any Zoanthid species. It is
as yet too early to foretell, what the conditions are in the antarctic region, but I am of opinion, that
they are similar there. The material at my disposal from this region is, however, too limited to allow
of any certain decision. The Zoanthid fauna seems to be poorer and to decrease more quickly towards
the south, than is the case in the northern waters towards the north.

Section II.

Contribution to the systematic classification of the Zoanthidae.

Among the Anthozoa, at least among the forms generally comprised under the name sea-
anemones, there is hardly a group which is so uniform in its morphological characteristics as the
Zoantharia (Zoanthidae). The few genera are generally easily distinguished from each other, whereas
it is more difficult to separate the species within the different genera. A number of Zoantharia
species have been described especially in the older literature and almost exclusively from outer

ZOANTHARIA

- \ S

characteristics, which however are often so little distinct, that an identification is only possible in
exceptional cases. This is all the more difficult as the group of Zoantharia evidently comprises many
species that are probably in process of differentiation. An attempt to bring some order into the
classification was tried in 1891 by Haddon and Shackleton, who quite reasonably founded their
classification on anatomical characters. Other scientists, as Duerden and several others, have followed
in their footsteps but we are still without sufficiently good characteristics for the separation of quite
a number of species.

Thus, many of the characteristics on which the classification of the species has been founded
are found to be of small importance. Regarding the appearance of the ccenenchyme, firstly, it may
sometimes give us good hints but we still know too little of its variations, which are caused by the
object on which the ccenenchyme is fixed. That a variation takes place is almost certain, but its
limits cannot be determined as yet. That the ccenenchyme may have a different appearance in the
same species is seen in Epizoanthus iucrustatus, which may have both a carcinoecium-forming ccenen-
chyme and a slightly tube-shaped ccenenchyme, on the supposition that the free variety barlesi of
E. incrustatus belongs to this species. Pax' investigations of West Indian species of Palythoa seem
to indicate, that a variation occurs, even though it seems possible here that separate species have
been dealt with. The canal-system in the ccenenchyme might also be of use for the separation of
the species, though but very little information thereon has been published as yet.

The outer appearance of the polyp may sometimes show very good characteristics for identi-
fication, but the species are often so little distinguished from each other that two polyps alike in
outer appearance may nevertheless belong to 2 different genera (cf. e. g. figs. 13, 19, PI. 1). The relation
between height and breadth has been used for differentiation of species, but is such a weak character
that the different degrees of contraction in different polyps may change the proportion between height
and breadth. Even the capitular region and the distal contours of the polyp are always somewhat
different in appearance according to the amount of contraction. Thus, the greatly distended polyps
of one species cannot be summarily compared with the greatly contracted ones of another. The
furrows on the capitulum, which generally correspond to half the number of mesenteries, are also a
much used, specific character, but this method has the fault, that the character is variable, as furrows
are not always found corresponding to the youngest mesenteries and the number of mesenteries and
thus also the number of capitular furrows change according to the age of the polyps, the older ones
having more mesenteries and consequently more capitular furrows than the younger, and even in the
former a variation also occurs though within certain limits. In characterising the species according
to the capitular furrows, it is thus necessary to pay attention to well-developed polyps, which often
necessitates having large material.

Most of the Zoauthidae are, as already known, iucrusted with foreign bodies, foraminifera,
sand-grains and sponge needles. Regarding the incrustation generally, it seems in each separate
species to consist of the same material, as shown by Haddon and Shackleton, though small
variations naturally always occur; but I know more than one case, especially in I. bulbosus, where
two different specimens of the same species have had quite different incrustations, for which reason I
think it possible that similar conditions may be observed among other species. Though, in my

ZOANTHARIA

opinion, a different incrustation in two otherwise similar forms does not entitle us to set up two
different species, and the incrustation thus theoretically is of no great value for the characterization,
yet in practice, owing to what has been said above, it may be used to help in the characterization
of a species.

Regarding the arrangement and appearance of the tentacles, they give at least in preserved
specimens no assistance in the identification of the species, the appearance and arrangement being
almost the same in all species of Zoanthidae. The number varies in different species but as it is
dependent on the number of mesenteries, it is of no practical importance for the classification.

Even the structure of the oesophagus provides no basis for the identification of the species, as
it is fairly uniform. Whether it is elongated or not, whether the diameter is small or large, is
generally dependent on its more or less contracted state. The appearance of the siphonoglyphe is
only exceptionally of importance for the classification, especially as in the Zoanthidae, in contrast to
what we find in the Ceriantharia, it is only the directive mesenteries which are always attached to it
The same applies to the prolongation of the siphonoglyphe (hyposulcus) which, at any rate in all species
examined by me, showed almost the same degree of development.

As to the finer anatomical structure, the body-wall, especially the structure of the mesoglcea,
provides one of the best characters for the separation of the species, even though variations may
sometimes occur within the same species. The different sizes of the ectoderm, endoderm and mesoglcea
in relation to each other should be fairly constant in the different species, whereas the size of the
germ-layers varies with the state of contraction. The ectoderm may vary greatly in appearance in
the different species but above all the appearance of the mesoglcea is of importance for the
classification, as it either contains but few cells, or is provided with numerous cells, cell-islets or
lacunae arranged in a manner often very characteristic for the species.

The appearance and structure of the sphincter help to characterize the genera but are not
always of such great importance for the separation of the species, though in a few cases very
characteristic sphincters occur. It must also be observed that there is a variation in the appearance
of the muscle, which at least in many cases may be connected with the state of contraction of the
sphincter.

The number of the mesenteries gives a very good character for the separation of the species,
but the variations are not so unimportant, even in full-grown polyps. Furthermore, it has to be
mentioned, though already pointed out previously in discussing the capitular furrows, that the
mesenteries increase in number with age, so that only full-grown specimens of different species can
be compared with certainty. The breadth of the micro-mesenteries may vary in different species,
though this is fairly seldom, as it is generally of importance for the separation of species. It must
specially be pointed out, that in different species the breadth is compared at the same part of the
body, as for example the lower part of the oesophagus, the micro-mesenteries in the different parts of
the body being of extremely varying breadth, in the distal part well developed but tapering quickly
downwards. But even if we consider this, we run the risk of making mistakes in classifying, as the
state of contraction of the pylop changes the position of this zone very considerably. The appearance
of the longitudinal muscles in the mesenteries may often be very characteristic, but even here we

ZOANTHARIA

must notice, that a specimen expanded broadwise gives quite a different appearance from a specimen
with mesenteries contracted broadwise. The parieto-basilar muscles seem generally to be weak,
sometimes they may be more differentiated, but are on the whole of small importance for classification.
The distribution of the longitudinal and the parieto-basilar muscles on the body-wall is sometimes
small, sometimes greater and is sometimes of use for the separation of the species. The macro-
mesenteries project more or less into the gastrovascular cavity, so that it would seem as if this might
be a fairly useful character. It must be pointed out, however, that the appearance of the mesenteries
is quite different in contracted and expanded specimens of the same species and it is also of import-
ance in the same respect whether the sexual organs are developed or not. If the sexual organs are
much developed, namely, the mesenteries are considerably broader than is otherwise the case.

The structure of the filaments is of no great use for the classification of the species, as it is
mainly the same in all forms.

As has been pointed out, there is great uniformity in structure and appearance in most of the
species within the genera, for which reason the identification of many species is distinctly difficult-
As most of the Zoanthidae are besides incrusted so much, that in many cases it is quite impossible
to get moderately good sections, it is obvious that the identification of Zoauthidae-species and the
setting up of new species is in most cases a matter of considerable difficulty. It was of great import-
ance, therefore, to find some more pecularities of organisation, which showed such great differences
in the different species, that they could be used for their identification. As I have found regarding
the Actiniaria, that the structure, size and arrangement of the nematocysts provide good characters
for identification, I have investigated if the same was the case in the Zoantharia. Even if this is not
so much the case in the Zoantharia as in the Actiniaria — as the first-named show great uniformity
probably even in the nematocysts, the structure, size and arrangement of the nematocysts in the
Zoantharia may nevertheless contribute to the identification of the species. As in the Actiuaria there
may certainly be some species of a genus which have almost the same distribution, structure and
size of the nematocysts, whereas other species may show great differences in this respect. As the
length and breadth of the nematocysts seem to be constant — of course with a certain amount of
variation - - the measurements of the nematocysts are in my opinion more suited to the determination
of a species than most of the measurements of Zoanthidae, even more suited than most of the other
structural characters, though of course with certain exceptions. In the following I have also taken
account of the nematocysts as far as possible in the description of the species. Especially the large
nematocysts with much coiled spiral threads, which are found in the body wall and filaments, some-
times in the tentacles and the oesophagus, appear to be of varying size in the different species. It
must be observed that the range of variation seems great in certain cases. It is possible, however,
that this condition is only apparent. I cannot set aside the possibility, namely, that some of the
large nematocysts with greatly twisted threads, which have a thinner wall than the other capsules,
may to some extent change their dimensions in different liquids of preservation, i. e. not be quite
resistant. The relation between length and breadth would thus be different in varying degrees of
contraction. I cannot however express my opinion on this point with certainty, as none of the exper-
imental proofs in this respect could be made by me. Without denying the possibility that the large

ZOANTHARIA

neniatocysts may change their form a little in the different liquids of preservation, these capsules may
nevertheless be considered resistant on the whole. This is also indicated by the agreement in
numbers I obtained in species where a large material was examined. It seems to me at any rate,
that data regarding the structure, size and distribution of the neniatocysts must be taken into con-
sideration in the characterisation of the different forms of Zoanthidae. Such data may often give
reliable information as to whether we have a constant species before us and are at any rate for the
sake of control of great value.

The arrangement, size and structure of the neniatocysts have been examined in preparations
embedded in glycerine diluted with water. As to the filaments it is generally very difficult to separate
them from other parts of the mesentery. Parts of these break loose when the filaments are removed.
We might imagine, therefore, that the neniatocysts are not always lying in the filament but in other
parts of the mesentery. This does not seem however — at any rate not as a rule — to be the case,
as I have found none of the capsules characteristic of the species in sections of the non-filamentous
part of the mesenteries. There are exception to this rule however, to be mentioned later in the
present paper. In a bottle with 6 colonies of Epizoanthus incrustatus from the neighbourhood of
Iceland I found that two of the colonies had some peculiar, egg-shaped neniatocysts in the mesenteries,
which were not present in the other colonies from the same locality. At first sight I thought I had
another species before me or at any rate a variety, but as I could find no other characters separating
these colonies from the normal ones, I had to look for another explanation. This was soon obtained,
all the sooner because it struck me in the first examination that these neniatocysts closely resembled
the neniatocysts of Hydrozoa. In this case they should not lie in the filament itself but inside this
in the entoderm. On closer examination of the section this was found to be correct. The egg-shaped
capsules have thus undoubtedly been taken in together with the food. I have found the same kind
of neniatocysts in a colony of Epizoanthus erdmanni also from Iceland. Even in this colony the
capsules seemed to be lying in the entodermal part of the mesentery, though the fixing was hardly
so good here that they could be said with absolute certainty to be found in the entoderm only. If
this kind of unusual capsule occurs in the filament, especially if only in certain specimens of a species,
there is reason to suspect that we are dealing with capsules that have penetrated into the animal
from without and not a normal component. I think it necessary to point this out specially for the
sake of future investigations.

In all the specimens examined by me the neniatocysts are almost always arranged in the same
way. In the ectoderm of the ccenenchyme and of the body-wall only neniatocysts with greatly twisted
thread are found. Regarding the distribution of the neniatocysts in the body wall, they are most
numerous in the proximal part, in the capitular region they are scarce or absent Yet sometimes the
nematocyst-capsules there are more numerous and of a different size and appearance than in the other
parts of the body-wall. In the ectoderm of the tentacles there are always extremely numerous
spirocysts (thin-walled capsules), less numerous typical, thick-walled capsules, sometimes similar capsules
as in the body-wall, though never abundantly.

The oral disc shows, in the few cases I have examined this, the same distribution of the
capsules as occurs in the tentacles. In the oesophagus there is mostly thick-walled capsules, in some

ZOANTHARIA

of which the basal part of the spiral thread is fairly distinct; more seldom and more scattered we
also find some nematocysts of the same kind as in the body-wall. In the filaments we find the same
sort of capsules as in the body-wall, sometimes in two different sizes, and also some thick-walled
capsules through which the basal part of the spiral thread can be seen and often, further, typical,
transparent thick-walled capsules.

Though I hope that the nematocysts of the Zoantharia species may be of use in the identifi-
cation of these species and make this to some extent easy, I am however fully aware that we are
still far from having discovered the special characters of many species. The large number of
Zoanthidae described in this paper may appear surprisingly great to many Actiniae specialists. Rut
I would remark, that the material investigated from northern and arctic seas is undoubtedly the
largest that any scientist has had for examination. It is of course quite possible, that later investiga-
tions may show, that some of the species described here are varieties of other species or that what
is considered a variety here may come to be regarded as a separate species. Taken on the whole, I
feel convinced, however, that the number of species will not be much reduced, as most of the species,
of which I have had a rich material, are certainly good species.

As already pointed out in 1900, the distribution, size and structure of the nematocysts are in
the Actiniae of no small importance for the identification of the species, a theory that has been con-
firmed by my later investigations on the Actiniae. Pax doubts their importance, but so far as I can
find, he has not made any extensive investigations on a large number of species to clear up the
question. He admits, however, that in a few cases the capsules may serve as good characters. As
evidence for his view he refers to some measurements made by me on 3 species belonging to the
genus Actinioides and finds them to be almost the same, from which he draws the conclusion that
the nematocysts are of no great importance for the classification. I do not agree with him here, for
the same might be said about any organs of the species, if we agreed with Pax's standpoint. How
often do we not find, that the sphincters, the arrangement of the mesenteries and a great many other
organs show agreement in many species of a genus of Actinaria, yet nobody would deny their great
importance for the classification of this group. The occurrence of certain kinds of nematocysts, their
size and arrangement, is a character as good as any, even if it is not always of importance for the
separation of closely-related species. For the separation of many genera of Actinaria they may also
be used with advantage, for, so far as I have found in the abundant material investigated, many
genera have nematocysts of a certain nature and arranged in a certain manner. It is at any rate a
fact, that the nematocysts are found to be indispensable for the separation of the species, as soon as
the expert has recognized their utility. In some cases, I may say, it is only a closer study of the
nematocysts, which has given a starting point for the separation of the species belonging to two
nearly allied genera — species which showed so great a resemblance that it would hardly have been
possible to separate them, had not the different size of the nematocysts in certain parts of the body
opened up the possibility for a grouping of the species. In another paper I shall deal further with
these features. I would therefore recommend those who write on the Actiniaria, to pay particular
attention to the arrangement and structure of the nematocysts, being convinced that many systematic
errors would be avoided if the capsules were only subjected to a proper examination.

ZOANTHARIA

Section III.

Description of the species.

Family Macrocneminae H add on &; VS hackle ton 1891.
Genus Epizoaiitlius. Gray 1867.

Macronemic Zoantharia with a single mesoglceal sphincter muscle. The body wall is incrusted.
The ectoderm is usually continuous but may be discontinuous; cell-islets and lacunae often in the
mesoglcea. Dioecious polyps connected by ceenenchyme, which may be band-like, incrusting or greatly
reduced, as in the free forms.

As H add on and Shackleton have given a good diagnosis of the genus, I have used it
in the main here. Of the n Epizoanthus species described here 4 are new: lindahli, danielsseni,
beercnislandicus and koraii. E. incrustalus and pagurupliilus have previously been described in detail by
Had don and S hackle ton (1891) but their description needs supplementing on several points.
Regarding E. norvegicus these authors also give some anatomical information and show that Mardcel
erdmanni Dan. is an Epizoanthus-species. The other species are described entirely from outer appearance
or the anatomical description is so bad, that it cannot be used for a characterization of the species.

Four of the species E. incrustalus. paguripliilus, lindahli and koreni have been dredged by the
Ingolf-Expedition.

Synopsis of the Epizoa ntli «j-species described here

A. Species with carcincecium

a. Without ventral polyp. Ectoderm of the body wall continuous.

b. The capitular region of the polyps in the contracted state truncate, disc-like, number of

mesenteries 32 — 42 incrustatus.

bb. The capitular region of the polyps in the contracted state not truncate, not disc-like,

number of mesenteries about 46 abyssoriun.

aa. With ventral polyp. The ectoderm of the body wall discontinuous, except in the capitular
region ; number of mesenteries 64 — 80 paguriphilus.

B. Species without carcincecium

a. The ectoderm of the body wall in the polyp discontinuous norvegicus.

aa. The ectoderm of the body wall in the polyp continuous,
b. Single unattached polyps or free colonies.

The Ingolf-Expedition. V. 4. 2

IO ZOANTHARIA

c. The large nematocysts of the filaments and of the capitular region have the same
structure, narrow and long (4 times longer than broad), unlike those in the other parts

of the body wall lindahli.

cc. The large nematocysts of the filaments are of moderate length (length being at most as
3-5 times breadth). The capsules of the capitular region, if any, resemble those in the

other parts of the body wall crdmanni.

bb. Polyps and colonies attached. The ccenenchyme more or less developed.

d. The large nematocysts of the filaments are narrow and long (the length being more
than 4 times the breadth). The capsules of the capitular region of the same kind,

but unlike those in the other parts of the body wall danielsseni.

dd. The large capsules of the filaments are of moderate length (the proportion between
length and breadth being at most as 3-5 to 1). The capsules of the capitular region,
if any, resemble those in the other parts of the body wall.
e. The sphincter comparatively feeble, number of mesenteries about 32. The large

nematocysts of the filament 22 — 31 // long, 12 // broad roscus.

ee. Sphincter strong

f. The large nematocysts of the filaments 34—41 n long and 10 — 12 // broad.
Cell-islets and lacunae often found at the base of the insertion of the mesen-
teries, number of mesenteries 38 — 42 bcerenislandicus.

ff. The large nematocysts of the filaments 26 — 36// long and 10 — 12/,! broad. Cells
numerous, cell-islets more scarce in the mesoglcea of the body wall, but not present
near the base of the mesenteries; number of mesenteries 36 — 52 .... glacialis.
fff. The large nematocysts of the filaments 26 — 29// long and 10// broad. Numerous
oval or round and separate, large cell-islets, further, large lacunae containing
cells in the mesoglcea of the body-wall; number of mesenteries about 36. . korcni.

Species Epizoanthus incrustatus Diib. & Koren.

PI. 2, fig. 26.
Mammillifera incrustata n. sp. Diiben &. Koren 1847. Forhandl. Skand. naturf. Mode p. 268. Isis 1848

p. 536. Sars 1851. Nyt Mag. Naturv. 6(2), p. 142, Danielsseu 1859. Nyt
Mag. Naturv. n, p. 45.
Zoanthus incrustatus Diib. & Koren, Sars i860. Forhandl. Vidensk. Christiania, p. 141. Forh. Skand.

Naturf. Kobenhavn 8, p. 691.
Polythoa arenacea d. Ch. p.p. Andres 1883 Le Attinie, p. 522.

Epizoanthus incrustatus (Diib. & Koren) Had don & Shackle ton, Se. Trans. R. Dublin Soc. 1891,

p. 636, PI. 58, figs. 1 — 22, PI. 59, fig. 2, PI. 60, fig. 1 (contains a complete syno-
nymy and list of literature of this species up to 1891).
Epizoanthus americanus n. sp. Verrill. 1867. Mem. Boston. Soc. Nat. Hist. 1, p. 34, 45.
Palythoa incrustata Roule 1900. C. R. Acad. Sc. Paris. 131 1900 p. 279.
Sidisia incrustata Dub. & Koren Arndt Jahr. Schl. Gesells. vat. Cultur 1912, p. 123.

ZOANTHARIA IX

Occurrence. Jutland Reef 60-130 fathoms, M. Uddstrom 1873, R. M.

Jsederen 100—150 fathoms, M. Olsson 1877, R. M.

Bergen Koren, R. M.

N. W. of Bergen 100—200 fathoms, M. Olsson 1877, R. M.

Finmarken Karlso N. of Tromso 70 fathoms, Goes & Malmgren, R. M.
— 90 fathoms, Malmgren 1864, R. M.
Foldenfjord, 530 m. 6-4, Nordgaard.
Vestfjord, clay ir8 1877, St. 252 N. N. Atlantic. Ex., Bergen M.

6i°i6'N., i°iS'E. 150 m. Sand, mud, shells. Greenland Ex. 21/5 1899, R. M. St. 58 Michael Sars
Ex. 1900 30/8 Bergen M.

66°35'N., 23°47'W. 117 Danish fm., bottom temperature 6-5°. Ingolf-Exp., St. 29, Cop. M.

50°57'N., io°46'W. 184 m. St. 96, 27/7. 1910 Michael Sars Exp., Bergen M.

(75 miles S. off Marthas Vineyard 86 fm., from U. S. N. M., R. M.)
off Marthas Vineyard U. S. Fish. Comm. Cop. M.)

400 40' N., 690 30' W. 23/5. 1888, R. M.

(40°oi'i5"N., 7o°22'W. 98 fm., U.S. Fish. Comm. Albatross, R. M.).

Sandy Hook Shinnicock Bay, 18 fm. Josephine Exp., R. M.

N. America, Bank of New Yersey, R. M.

Size: The largest colouy I have examined — the colony had no less than 18 polyps — had
a length of 2-5 cm. and a breadth of 1-3 cm. not comprising the polyps. The largest polyp when con-
tracted had a length of n cm.

Colour: Light sandy-coloured or dark-gray in alcohol.

External appearance: As the outer appearance of the colonies has been described in
detail by H addon cc Shackle ton (1891), I shall here only give a short description of the
carciucecium-forming typical forms. The cceneuehyme is well developed, forming the carcincecia
originally on gastropod-shells, which are inhabited by hermit crabs. In older specimens the polyps
are arranged irregularly on the dorsal side of the carcincecium. In the largest specimen I counted
no less than 18 polyps, thus a larger number than observed by Had don and Shackle ton. No
ventral single polyp is found as is the case in E. abyssorum. Had don and Shackleton state, that
in younger colonies the polyps are arranged in three series and describe their arrangement. Even if
the development seems in many cases to proceed as described by Haddon & Shackleton, there is
undoubtedly a great number of exceptions from the rule laid down by them. The only thing I have
been able to determine with certainty is, that during the 2-polyp stage, one of the polyps lies nearer
the apex of the gastropod, the other near the entrance to the carcincecium, to begin with over the
opening or even laterally, and that the third polyp is formed between these two. For my part I
think it most probable, that the places where the polyps are formed are to a great extent dependent
on the shape of the gastropod. Be this as it may, practically, the arrangement of the polyps in three
series in the young specimens has hardly any importance for the classification. The polyps are
cylindrical, the larger double the height of the smaller. On the contracted specimens with retracted
tentacles the distal part of the polyp is broader than the other part and forms "a flattened disc-like

I2 ZOANTHARIA

termination" (H. & S.), so that seen from the side the distal part is sharply truncate. The capitular
furrows are well-marked, in smaller polyps the number is 15, in larger about 18, sometimes even 22.
In dark specimens these furrows seem to be more distinct. The polyps show a slight bending at the
entrance of the carcincecium, i. e. forwards. The polyps as well as the carcinoecium are strongly
iucrusted with sand-grains. As opposed to what we find in E. paguripliilus I have seen no trace of
the cuticle in this species.

The oesophagus is short, the siphonoglyphe distinct with a well developed hyposulcus of almost
the same length as the oesophagus. Haddon & Shackleton state that the siphonoglyphe is
"somewhat" indistinct. It may be, that they have come to this result, owing to their sections passing
through the uppermost part of the oesophagus, where the siphonoglyphe is not distinctly developed as yet.

Anatomical description: Haddon and Shackleton have described the anatomy of this
species. On several points I am able to supplement their description. The ectoderm of the body-wall is
continuous and fairly low. It contains a large number of nematocysts with strongly twisted thread (length
22 — 24 fi, breadths — 10 p). Owing to the strong incrustation it is difficult to judge of their distribution
on the different parts of the bod}-. The mesoglcea is several times broader than the ectoderm. It is
generally fairly homogenous, but contains here and there some scattered small cells and in the inner part
very few cell-islets and lacunae. The ectoderm is thinner than the ectoderm. The incrustations are rather
strong and consist almost exclusively of fairly coarse sand-grains, which fill the whole of the body-wall
and may sometimes, as mentioned by Haddon and Shackleton, even penetrate into the coelenteron.

The sphincter is short but strong, the muscle-fibres are large and separated by narrow bauds
of connective tissue. In contracted specimens the sphincter is broad in the upper part, often filling
up almost the whole breadth of the mesoglcea, but narrows quickly downwards.

The ectoderm of the tentacles is as usual high and contains numerous spirocysts. Thick-
walled capsules if any are very small.

The ectoderm of the oesophagus is high and provided with numerous thick-walled, narrow
nematocysts (length 17 — 19//). I have also, though seldom, found similar nematocysts as in the body-
wall. The ectoderm of the siphonoglyphe is lower, and the mesoglcea is in some cases greatly
thickened in other cases less so, owing to the greater or less development of the siphonoglyphe.

The number of mesenteries is somewhat variable. In smaller specimens I have found 32
mesenteries (18 macro- and 14 micro-mesenteries); a larger specimen had 36 mesenteries, another 38
(10 macro and 9 micro on the one side and n macro and 9 micromeseuteries on the other). The
greatest number of mesenteries I have observed was 42, in which specimen the one side had one
macro- and one micro-mesentery more than the other side. The micro-mesenteries are weak and in
the lower part of the oesophageal region and under the oesophagus they reach only a little way
into the coelenteron. The longitudinal as well as the parieto-basilar muscles are weak and the distribution
of these muscles on the body-wall is also inconsiderable.

The filaments have the usual structure. In the cnido-glandular tract we find sometimes sparsely,
sometimes more frequently, nematocysts with spiral thread which are broader at the one side than at
the other (length about 24//, greatest breadth about 7—8^), further frequently thick-walled capsules
(length 22 ft, breadth 3//).

ZOANTHARIA

13

&»****

In the mesenteries of a few specimens taken at St. 129 by the Ingolf-Expedition I found
numerous egg-shaped nematoeysts, sometimes large (length 19-24/*, breadth 14—17^), sometimes
smaller (length 17 p, breadth 7 p) and also some intermediate sizes. As these only occurred, however,
in a few colonies and were wanting in others from the same locality, the doubt arose whether these
capsules were of normal occurrence. Sections showed also, that the capsules did not lie in the
cnido-glandular tract itself but in the ectoderm immediately within this. It is therefore most probable,
that these nematoeysts have been taken in with the food and that they are the nematoeysts of
hydroids, which they greatly resemble.

The species is dioecious.

The walls of the carcincecium have the
same structure as the body-wallj of the polyps.
The ectoderm is provided with a thin cuticle
and contains nematoeysts of the same kind as
in the body-wall, which are especially num-
erous on the outer side of the carcincecium.
The ectoderm seems to be somewhat thinner
on the inner than on the outer side and is by
comparison with the mesoglcea very thin. The
mesoglcea resembles the body-wall mesoglcea
of the polyps and is very much incrusted. The
canal-system (c text-fig. 1) of the entoderm is 3
greatly developed and lies almost halfway be-
tween the outer and inner margins of the car- Text-figure 1-3 Transverse section through the free margin
cincecium. The canals are large and broad and <outer HP) of Uie carcincecium of Epizoanthus incrustatus (fig. 1),

E. abyssorum (fig. 2) and E. paguriphilus (fig. 3. The mesoglcea

fuse together to irregular lacunae, which form and partly also the ectoderm are seen but not the epithelium in the

, rr,, , , .,, , .•, canal-system, c canals; cc marginal canal,

a network. I he mesogloeal pillars between the

meshes are rather weak, though not so indistinct as in E. abyssorum-. Along the upper margin of

the carcincecium runs a canal (cc) as in K. paguriphilus. The canal is somewhat broader than the rest

of the canal-system.

Remarks. Danielssen (1890, p. 136) states that a specimen of Epizoanthus arctic us was

obtained at St. 252 on the Norwegian North Atlantic Expedition. From Bergen Museum I have

received a colony under this name and from the above-mentioned station. The colony consisted

however of E. incrustatus. This is probably due not to an erroneous determination of Danielssen,

but more likely to a confusion of localities, for he mentions at the same time that he obtained

specimens of (Zoanthtis) incrustatus from St. 200.

Epizoanthus abyssorum Verr.

PI. 2, fig. 8, PI. 3, fig. 1, PI. 5. fig. 7.
Epizoanthus abyssorum n. sp. Verrill p. Amerie. Journ. Sc. 29 1885, p. 151.

Verr ill Results Expl. Albatross 1885, p. 535, PI. o, fig. 27 b.

I4 ZOANTHARIA

Occurrence: (370 N., 7i°54'W. 2021 faths. U. S. Fish. Comm. Albatross St. 2226 from U. S.
Nat. Mus. R. M.).

Dimensions: On the single specimen I have had for examination the carcincecium was
2-5 cm. long and 23 cm. broad. The largest contracted polyp had a height of 1*4 cm. and a breadth
at the base of 12 cm.

Colour grayish white purple or orange tinted at summit (Verrill) — in alcohol: whitish.

External appearance: The carcincecium is snail-shaped with wide opening. On the inner
side there seems to be a distinct cuticle as in E. paguripliihis. On the dorsal side of the carcincecium
emerge 3 large polyps (fig. 8, PL 2) resembling those of E. paguripliilns. They are broadest at the
base, narrower upwards, somewhat wider in the distal part. The capitular region is uneven in the
contracted state and does not form such a distinct, flat disk as in E. incriistatits, being more like
E. pagiiriphilus. The capitular furrows are very indistinct in all the polyps. On each side of the
entrance to the carcincecium is a polyp, one of which covers the apex of the shell, which in contrast
to the other, totally disintegrated part of the gastropod is quite fresh and occupies the greater part
of the gastrovascular cavity of the polyp - - the third is placed between these two polyps but a good
deal further back on the first spiral of the carnincecium. Ventral polyp not developed. All the polyp-
part as well as the carcincecium is strongly incrusted with foraminifera.

The oesophagus is not long, the siphouoglyphe distinct with well-developed hyposulcus.

Anatomical description: The ectoderm of the body-wall is of moderate height, continuous
and contains some equally broad nematocysts with rounded ends and greatly twisted thread (length
24 — 29 fi, breadth 10 ft). Presumably they are almost always present (the ectoderm was partially
removed). The mesoglcea is thick, fairly homogeneous with here and there scattered spool-shaped
cells, but no cell-islets (if present they are very scarce PL 5, fig. 7). The entoderm is almost as broad
as the ectoderm. The incrustation, which consists almost exclusively of foraminifera, though also of
sand-grains, fills out the ectoderm as also the mesoglcea in the body-wall.

The sphincter (PL 3, fig. 1) is strong, mesoglceal, finely meshed with the muscle-fibres running
transversely. In the distal part it occupies the whole of the mesoglcea.

The ectoderm of the tentacles has the usual structure. The spirocysts are extremely numerous
in it and the thick-walled capsules are very scarce, if the few met with are at all normal constituents
of the ectoderm. The ectodermal longitudinal muscles are strong, the mesoglcea thin.

The ectoderm of the oesophagus is high and contains numerous typical nematocysts (length
24—26 ft). Whether other capsules also occur, I am not able to say with certainty owing to the strong
contraction of this region. The mesoglcea is thin as usual. The siphonoglyphe and the hyposulcus
have a thick mesoglcea and generally a thin ectoderm.

The number of mesenteries is not large, especially when we consider that the polyps generally
have a considerable diameter. In the specimen examined by me — the section had a diameter of
07 cm. — the number was 46, 13 macro and n micro on the one side, 12 macro and 10 micromes-
enteries on the other. The mesoglcea of the mesenteries is thin; the longitudinal muscles on a part
of the mesentery form very few but fairly deep folds especially on the micromeseuteries and directive
mesenteries. The parieto-basilar muscles are weak and not found on the body-wall. The micromes-

ZOANTHARIA

J5

enteries are also weak and only project very little into the coelenteron. The filaments have the usual
structure. So far as I can see, the nematocysts of the same kind and size as in the body-wall are
scarce. The same is the case with the thick-walled capsules which are very narrow, often curved
and not much thickened (length 34—36 u).

Sexual organs. Eggs at different stages of development are found in the single specimen
examined by me.

The carcincecium. The inner wall of the carcinceciuni is bounded externally by a fairly thick
cuticle. Under this lies a continuous ectoderm with numerous nematocyst capsules of the same kind
as in the body-wall of the polyps. On the outer side of the carcincecium the ectoderm was for the
most part removed. The mesoglcea on both sides of the entodermal canal-system is fairly thick and
almost equally developed on both sides. The entodermal canal-system (text-fig. 2, p. 13) forms large
lacunae separated by very narrow bridges of connective tissue, by means of which the two layers of
the mesoglcea are easily separated from each other. In the single specimen I had for examination I
found no canal in the margin of the carcinceciuni that differed in size from the other parts of the
canal-system (text-fig. 2). Thus, the entodermal canal-system seems to be more developed than in
E. incrustatus; I have said, seems to be, for I have only examined the ventral margin of the carcinceciuni
a little way inwards. The difference in the development of the canal-system is seen most distinctly
on comparing E. abyssorum with E. paguripliiliis. The inner as well as the outer parts of the carci-
ncecium are richly incrusted with foraminifera.

Remarks. The claster of this species arising from a grain of sand (PI. 6, fig. 27a Verrill 1885b)
is probably another species. I have no knowledge of this form.

Epizoanthus paguriphilus Verr.

PL i, fig. 8.

Epizoanthus paguriphilus n. sp. Verrill 1882 Americ. Journ. (3) 23 p. 137, 316.

Verrill, Verrill 1883 Report Anth. Bull. M. Comp. Zool. Cambridge

p. 61, PI. 8, fig. 5.
Zoantlnis (Corticant/ms) paguriphilus Verr. Andres 1883 le Attinie p. 541.
Epizoanthus paguriphilus Verr. Haddon & Shackleton 1891, p. 641, PI. 58, figs. 23 — 25, PL 59,

fig. 6, PI. 60, fig. 5 (contains index of literature up to 1891).
Epizoanthus hirondellei 11. sp. Jourdan Bull. Soc. zool. France. Vol. 16 p. 269. 1891.

— Jourdan. Jourdan Res. Camp. Albert I. Monaco Fase. 8. p. 7 Tab. 1. figs. 3 — 5. 1895.

Occurrence: 6i°44' N., 270 W. 485 Danish fathoms; bottom-temp. 6i°. Ingolf-Exp. St. 81, 2 sp.
6i°28'N., 26°25'W. 780 Danish fathoms; bottom-temp. 4-3°. Ingolf-Exp. St. 75, 1 sp.
6o° 7' N., 9° 33' W. 750 m. Michael Sars Exp. 14-8. 1902. St. 79 b. Bergen Museum.
59° 28' N., 8° W. 1100 — 1300111. temperature at 1000 m. 8-07°. Michael Sars Exp. 12-8. 1902. St 76.
Geographical distribution. North Atlantic N. E. coast of America to N. W. Europe in
deep water (H. & S.), Azores J. Roule.

Dimensions: The largest carcincecium had a length of 6 cm. and a breadth of 4-5 cm. The
largest polyps were in the contracted state about 1-5 cm. broad and 1 cm. high, the smallest colony
was 2-5 cm. long and 1-5 cm. broad.

j6 zoantharia

Colour: Brownish or gray in spirit specimens. Verrill gives the colour as "translucent
bluish or purplish-gray or grayish brown. The tentacles pale orange or salmon with lighter tips.
The polyps more or less of a salmon colour".

The external appearance has been well described by Had don and Shackle ton. The species
always forms large carcincecia inhabited by Eupagurus pilosimanus. The coenenchyme develops on
the gastropod shell which it covers completely, thus forming some kind of shelter to the gastropod,
especially before its shell is dissolved (PL i, fig. 8). The polyps are arranged in 2 groups an outer
consisting of a row of large polyps -- 10 in the largest colony examined by me — and an inner one
consisting of a single, smaller polyp lying centrally on the ventral side of the carcincecium a little
behind the opening of the carcincecium.

The marginal polyps in contracted specimens are broader than long and elliptic in transverse
section. Some of the polyps on the sides of the carcincecium seem to be larger than the others, some
smaller polyps occurring in the posterior region, though this is not always very apparent. Whether
such a small "posterior" polyp is of normal occurrence, as stated by Haddon and Shackleton, I
am unable to say for certain, but it seems hardly to be the case to judge from my specimens. But
my material as well as Haddon and Shackleton's is too small to permit of any certain statement
on this point, so that it may be left undecided, as also the question regarding the arrangement of
the polyps. As this species seems to have been taken in great numbers during the German deep-sea
expedition, I shall come back to this question later.

Capitular furrows occur but are indistinct in the preserved specimens partially owing to the
irregular contraction of this region.

The species is slightly incrusted with foraminifera, mainly covering the polyps and the
neighbouring parts of the coenenchyme. The tentacles are very small.

The oesophagus is short with a deep siphonoglyphe and a well-developed hyposulcus, which has
the same length as the oesophagus.

Anatomical description. Haddon and Shackleton have given a good description of
the polyps of this species, but on several points their description requires supplementing.

As stated by Haddon and Shackleton the ectoderm of the body-wall is discontinuous.
This does not apply however to the capitular region, especially its upper part, where the ectoderm
as usual is thicker than at the other places of the body-wall. If the ectoderm is still present, there
is in the upper part of the body-wall a fairly common occurrence of equally broad, thick-walled
nematocysts (length 24—26//), but on the other hand no uematocyst capsules with greatly twisted
thread, which probably may be found in the lower part. The mesoglcea is very thick in comparison
with the ectoderm. It contains numerous but small cell-islets, which may sometimes be fairly-
elongated and even form canals. In conformity with the often-quoted authors I have not been able
to find any connection between the ectoderm and the entoderm and these canals. Spool-shaped cells
also occur.

The incrustation is inconsiderable and consists mainly of foraminifera together with some
sand-grains. These lie in the ectoderm and in the outermost parts of the mesoglcea. The entoderm
is thin and has almost the same size as the ectoderm. Haddon and Shackleton have given a

ZOANTHARIA 17

very instructive figure of a transverse section in PL 59, fig. 6. It must be observed however, that in
ray specimens the strands of the mesoglcea, separating the different parts of the ectoderm from each
other, do not always lie so closely as in this figure.

As mentioned by Had don and Shackleton the sphincter is not strongly developed, espec-
ially if the size of the polyps is taken into consideration. In the distal part of the sphincter, however,
the fibres occupy almost the whole breadth of the mesogkea, the lower third part of the sphincter
being inconsiderable. Had don and Shackleton state that "no cavities are visible, the fibres
being completely embedded in the substance of the mesoglcea." This is not the case in my specimens.
In the proximal part, where the muscle-meshes (in transverse sections through the sphincter) are small,
it may be possible that there sometimes are no cavities, in the distal part on the other hand the
muscle-meshes are large and as usual extend in a transverse direction. The parts of the mesoglcea
lying between the muscle-groups are very small. The sphincter is thus fairly strong in this regard.

The ectoderm of the tentacles is high, the mesoglcea on the other hand is thin as also the
layer of longitudinal muscles. In the ectoderm very numerous spirocysts are found. Whether thick-
walled nematocysts occur is uncertain, but if present they are very scarce.

The ectoderm of the oesophagus is fairly high and provided with numerous, thick-walled
nematocysts (length 23 — 29 /i, generally about 24—26 fi). The mesoglcea is fairly thin. In the
siphonoglyphe the ectoderm is considerably thicker than in the oesophagus, with the condition reversed
as regards the mesoglcea. The mesoglcea in the siphonoglyphe is almost homogeneous, as cells and
cell-islets only occur very seldom.

The number of mesenteries is greater than in any other northern Zoantharia. In a small
polyp I counted namely 64 mesenteries, 17 macro and 15 micro on each side, in a large one 80
mesenteries. The macro-mesenteries are in the oesophageal region fairly thick, owing to the fact,
that the mesoglcea is well-developed here, whereas it becomes thinner below the oesophagus. The
longitudinal muscles are not strong and the muscular plaits few. The parieto-basilar muscles are very
weak and narrow. None of these muscles are expanded in the body-wall. The micro-mesenteries
are very weak — the weakest I have ever seen — and do not reach above the entoderm of the
body-wall.

The filaments have the usual structure. They contain nematocysts with greatly twisted thread,
but not in great number. They are oval and fairly small (length 19—25,0, breadth 10 — 12 /*). Further,
they contain fairly many thick-walled, rather transparent nematocysts with distinct spiral thread and
broader at the one end, with varying length (19—24 — 26—31^, breadth 6 — 7 /*) and also some thick-
walled, narrow, typical nematocysts (length about 26^).

The species is dioecious.

The carciiio'ciiiiu. The cceneiiehyme and the canal-system have not been examined by H addon
and Shackleton. The outer layer of the ectoderm had fallen off. The mesoglcea sends out a
number of fine outshoots, the presence of which indicates that the ectoderm is also discontinuous
here. On the inner side the ectoderm is thin and discontinuous with a well-developed cuticle. On
the outer side of the carciuceeium the mesoglcea is very thick, on the inner side it is thin. The
entodermal canal-system (c, text-fig. 3, p. 13) thus lies quite close to the inner side of the ccenenchyme.

The Ingolf-Expedition. V. 4. 3

iS

ZOANTHARIA

It consists of numerous reticular, anastomosing canals, which are generally fairly narrow but somewhat
thicker towards the opening of the carcincecium. A very large canal cc, which is in connection with
the other reticulate branched canals, runs along the upper rim of the opening of the carcincecium
and is afterwards lost in the columellar region, where it divides into some smaller canals. Numerous
cells and cell-islets occur in the thick part of the mesoglcea; in the part lying inside the canals, the
cells and cell-islets are very scarce. No incrustations are found in the mesoglcea.

Epizoanthus norvegicus (Kor. & Dan.) Hadd. & Shackl.

PI. i, fig. 12, PI. 2, fig. 22, PI. 3, fig. 3, PI. 5. figs. 2, 3.

Zoanthus norvegicus n. sp. Kor en & Daniel ssen. Fauna littoral. Norveg. 3, 1877 p. 79, Tabl. 9,

figs. 5-6.
Polythoa {Endeitkoa) norvegica (Kor. & Dan.) Andres Le Attinie 1883, p. 531.
Epizoanthus norvegicus (Kor. & Dan.) Haddon & Shackleton Scient. Trans. R. Dublin Soc,

p. 614, 132, 651, 652, PL 59, fig. 5.
Palythoa norvegica (Kor. &. Dan.) Arndt Jahresb. Schl. Gesells. vaterl. Cultur 1912, p. 123.

Occurrence: Norway Trondhjem Fjord: Skarn Sound on Primnoa 100— 200 m. 3 — 11/9, 1898,
0stergren R. M., Storm. Bergen Mus.

Haakon Sound 280 fans, from Bergen Mus. R. M.

(Korsfjord near Bergen 300 fans. Kor en & Daniel ssen, Sars).

Dives on sponges, shells of Lima excavata, Primnoa and Paragorgia (Kor en & Daniel ssen).

Dimensions: The greatest length of the polyps is 2-5 cm., greatest breadth in the distal
part o-8 cm., smallest breadth in the proximal part 0-5 cm. Outer tentacles cr8 cm., inner ones somewhat
longer (Kor en & Daniel ssen).

Colour (from Kor en & Daniels sen): "The body is grayish yellow, the inside of the
epidermis, the proper skin, is pale rose-coloured with a tinge of yellow. The mouth surrounded by a
darker rose-coloured ring, from which fine white stripes go radially to the interior tentacles".

External appearance: The polyps are considerably larger than broad, narrow at the base
and broader at the distal part. In the contracted state the distal part of the polyp is rounded not
truncate. The larger polyps at least have distinct capitular furrows, which are specially prominent
in expanded specimens, as they are broad. In the specimens I have examined the number of capitular
furrows was 16—20, in most specimens 20, and one specimen (a double individual, see below) had
even up to 24. Between the capitular furrows are distinct, fairly sharp ridges, which in the distal
part often form irregular, tap-like projections.

The polyps are connected with each other by means of a very well-developed ccenenchyme,
which is fairly thick and from which the polyps arise usually at a considerable distance from each
other. The canals from the polyps begin to communicate a little way from the polyps, forming a
network apparent to the naked eye.

The species forms large colonies. Koren and Dauiclssen state, that it is found "frequently

/HANTIIARIA

J9

in large groups that may occupy as much space as a closed hand, wherein more than 50 polyps are
attached by the same coenosark."

The number of tentacles corresponds to the number of mesenteries, being thus in larger
specimens considerably greater than stated by Koren and Daniels sen.

The oral disc is wide, the mouth lies on a cone, the mouth-opening is like a slit.

The oesophagus is short and the siphonoglyphe well-developed with distinct hyposulcus.

Fission. On the colony taken by Storm in Skarn Sound I observed a double polyp in the
middle part. (PI. 2 fig. 22). Almost the whole of the body-wall was continued smoothly without boundary
from the one polyp to the other, but the ridges and for the most part also the capitular furrows could
be seen in each polyp. The one polyp had 20, the other no less than 24 ridges and furrows. Each polyp
had its special circlet of tentacles fully separated. How far a doubling of the tentacle takes place
from the directive chamber, I am unable to say, as I did not wish to cut up the polyp completely
but there is probably* a directive tentacle 011 each polyp. Each polyp has its distinct oesophagus and
siphonoglyphe, but a common directive chamber. The cleavage has thus taken place in the directive
chamber. This condition has some resemblance to the double formations in Cribriua gemmacea
previously described by me (Studien liber Regenerations mid Regulationserscheinungen. K. Svenska
Yet. Akad. Handl. B. 37 1904 p. 82 text-fig. 13, PI. 2, fig. 21), of course with the difference caused by
the different organisation of the two groups.

Anatomical structure. Had don and Shackleton (1891) have given some information
regarding the anatomical structure of this species. They state that the ectoderm, the mesoglcea and
the entoderm of the body-wall reach a considerable size and that numerous nematocysts are found in
the ectoderm. Furthermore, they point out that the micromesenteries are strongly developed. In
their paper we find a figure showing a section of the body-wall — evidently from the capitular region.
Otherwise this species has not been subjected to any anatomical examination.

The ectoderm of the body-wall is very thick and discontinuous (PI. 5, fig. 3) except at the
capitular region (PI. 5, fig. 2), though the discontinuity is hardly so conspicuous as in Epizoanthus
paguriphilus. It contains numerous nematocysts with greatly twisted thread, which have a length of
24 — 29^ and a breadth of 12//; they are oval and almost equally broad at both ends. Haddon and
and Shackleton state that they contain pigment granules. This is however doubtful; I think it
probable that small air-bubbles have penetrated into the nematocysts in sectioning and that these
bubbles have been mistaken for granules. This often happens and I have had the same experience
with many Zoantharia, Ceriantharia and Actiniaria. The mesoglcea is considerably thicker than the
ectoderm and now and then runs out into outshoots which cut off parts of the ectoderm from each
other and even end in the cuticle, though without forming such small, closed spaces as in Epizoanthus
paguriphilus. The mesoglcea contains fairly many cells with outrunners, now and then cell-islets and
very seldom ectodermal lacunae. The entoderm of the body-wall reaches a considerable size. The
incrustation in this species is inconsiderable and lies mostly in the ectoderm and in the outer parts
of the mesoglcea, consisting of sand-grains, foraminifera and sponge-needles.

The sphincter is strong, mesogloeal and finely divided. The meshes in transverse section are
drawn out in a transverse direction. The sphincter lies nearer the ectoderm than the entoderm, so

3*

20

ZOANTHARIA

that in the furrows of the capitular region it is only separated from the ectoderm by a very small
part of the mesogloea, which in this region is generally higher than in the other parts of the body
and contains some nematocysts.

The tentacles have the usual structure. Besides the very numerous spirocysts the ectoderm
contains numerous, thick-walled capsules (length 14 — 17 /y>) and a few capsules of the same appearance
as in the body-wall (length 24 — 26 /i, breadth 10 ft).

The ectoderm of the oral disc is very broad near the tentacles and contains numerous, closely
packed spirocysts, near the mouth it is thinner and contains some nematocysts. The ectodermal
longitudinal muscle layer is fairly strong in the outer part of the oral disc, weaker in the inner part.
A layer of fibrillae and ganglion cells is distinctly visible in the oral disc.

The ectoderm of the oesophagus is high and arranged in longitudinal folds supported by
mesoglceal ridges, which emerge between the furrows. The nematocysts are scarce and thick-walled
(length about 20 u). Large-grained gland-cells are found especially in the inner parts of the ectoderm.
Ectodermal longitudinal musculature is absent in this species. At the base of the ectoderm of the
oral rim there seem to be numerous cells and a thread-like layer. As far as I can see — the
material was not so well preserved as could be desired — it consisted of a well-developed layer of

ganglion-cells and nerve-fibrillae. The mesogloea is fairly
thick; its upper part is provided with numerous cells which
are scarce in the aboral part. The ectoderm of the siphono-
glyphe is of the usual structure and lower than in the other
part of the oesophagus. The mesogloea is broad and much
thicker than in the oesophagus. The hyposulcus has the
same structure as the siphonoglyphe but the entodermal
muscles here run in longitudinal direction and form some
folds in the outer parts. The free border is thick and
even provided with more numerous gland-cells than the
inner parts.

The number of mesenteries varies according to
the size of the polyp. In a smaller specimen 24 meseu-

Text fig. 4. Transverse section through a piece of the teries were developed. 14 macro and 10 micro. Two
body-wall with mesenteries and oesophagus of Epi- larg.e poiyps had 46 mesenteries. They were both ir-

zoanthus norvegicus. Ectoderm shaded, mesogloea

and muscles black, entoderm not specially marked, regularly developed, the one side having more mesen-
dc: directive chamber. teries than ^ Qther Qne q{ ^ polypg j^ ^ m^Q

and 11 micromesenteries on the one side of the sagittal plane, and 12 macro and 10 micromesen teries
on the other. The other polyp had 11 macro and 9 micro mesenteries respectively and 14 macro and
12 micro. The micromesenteries are strong. The longitudinal musculature of the mesenteries is
vigorous and forms fairly numerous folds. The parieto-basilar muscles are weak. The distribution of
the longitudinal and the parieto-basilar muscles on the body-wall is slight. The muscles of the
micromesenteries are generally well-developed (text-fig. 4).

The filaments have the usual characteristic structure. The glandular tract contains only the

ZOANTHARIA 2I

frequently occurring nematocysts of the same kind and size as in the oesophagus. The species is
dioecious.

The ectoderm of the coenenchyme contains numerous nematocysts of the same shape as in
the body-wall, but seems here to be continuous. The mesogloea contains numerous ectodermal lacunae,
in which the large nematocysts, that occur in the body-wall of the polyps, are also found. The
entoderm is very large in the canals.

Epizoanthus lindahli n. sp.

PI. 2, figs, ii — 13, PI. 4, fig. 5
Zoaiitlius arc/ it us Marenzeller 1878, p. 379.

Occurrence: Baffius Bay 72°4'N., 59/50' W. 227 fms. Hard, gray clay. Ingegerd and Gladan
Exp. 19/7, 1871. Josua Lindahl 3 sp. R. M. (sp. a.)

79°i3'i//N., 63°2i/7"W. 230 fms. 1 sp. Museum at Vienna (sp. b.)

66°42'N., 26°4o'W. 590111. Temp, at 550111. o-n°. 3/8. 1900 Michael Sars Exp. St. 13 1 colony.
Bergens Museum (sp. c.)

65°oo'N., ii°i6' W. 310 Danish fms. bottom-temp. o-oi° Ingolf Exp. St. 59 1 sp. (sp. d.)

66°35'N., 56°38'W. 318 Danish fms. bottom-temp. 3-9° Ingolf Exp. St. 32 1 colony (sp. e.)

var. ATordgaardi Lyngeu, Nordgaard 1 sp. R. M. (sp. f.)

Dimensions: (a) Length of the colony about 2-i cm., breadth of the largest polyp o-6 cm., of
the smallest polyp 0-3 cm. (b) length of the colony about 1-5 cm., breadth 04 cm. (c) breadth of the
colony 23 cm., length of the largest polyp 1-3 cm., breadth 045 cm.

Colour iu alcohol: dirty-gray (c) sand colour with white points of foraminifera and black
points of sand-grains, specimen d dark with black sand-grains, f clear, uncoloured.

External appearance: The coenenchyme is inconsiderable and tube-shaped as in E. erdmanni.
The polyps are elongated just in E. erdmanni, narrowest at the base, increasing in size towards the
point. They are broadest in the capitular region. The body-wall is rough owing to the incrustations,
which mainly consist of sand-grains and also of foraminifera (especially in b). The upper contracted
border is somewhat rounded - - truncate. The capitular furrows are not so distinct owing to the
incrustation and contraction, on the largest specimen of the colony I counted 20, 011 b at least 16, on
d 18 probably.

The oesophagus is short, the siphonoglyphe distinct with a hyposulcus which is as long as the
oesophagus.

Anatomical description: (1 specimen from Baffins Bay and another from c have been
closely examined). The ectoderm of the body-wall is continuous and of moderate size, provided with
a cuticle, on which detritus particles are fixed. Iu the lower part of the polyp the ectoderm contains
many equally broad nematocysts with greatly twisted thread, having a length of 38 — 43 y> and a
breadth of 10- 12 p. In the capitular region similar but narrower capsules of the same kind and
dimension as in the filaments. The mesogloea is fairly thick, several times thicker than the ectoderm;
it is generally rather homogeneous with a frequent occurrence of very small cells and sometimes even
cell-islets (PI. 4 fig. 5). The entoderm is extremely thin in the body-wall as well as in the mesenteries and

ZOANTHARIA

the cesophagus and its differentiations. The ectoderm and the mesogloea are incrusted with sand-grains,
foraminifera and a fairly large number of sponge-needles. In e and f sand-grains were almost
exclusively present. The incrustation is often considerable and fills almost the whole of the mesogloea.

The sphincter is very strong and has some resemblance to the sphincter in E. erdmanni.

The tentacles have the usual structure. The spirocysts of the ectoderm are very numerous.
Besides there generally occur some thick-walled, equally broad nematocysts (length 17—19^) and more
seldom nematocysts of the same type as in the capitular region of the body-wall (length 38—48 ft,
breadth 7 fi). The ectoderm of the oesophagus is high and contains large numbers of equally broad
nematocysts with greatly twisted thread (length (38) 43 — 48 fi breadth 7 ft). Further, very numerous
typical thick-walled nematocysts occur (length 24 (26) ft). The mesogloea is thick. The ectoderm of
the siphonoglyphe is of the typical appearance, the mesogloea thick, though very little thicker than
that of the oesophagus.

The number of mesenteries was 38 in the specimen sectioned, on one side n macro and 9
micro-mesenteries, on the other 10 macro and 8 micro-mesenteries. In the larger specimen of the
colony the number was presumably 36 (it was opened partially lengthwise). Another from colony c
had 36, specimen d about 40. The micro-mesenteries are well-developed in the oesophageal region.
The mesogloea of the macro-mesenteries is fairly thick, the entoderm thin. The longitudinal muscul-
ature is moderately developed and forms few folds; in one specimen from colony c which had a very
wide oesophagus and the mesenteries consequently very contracted in breadth, the musculature lay in
thick folds, the mesogloea being also here thicker than in a, where the mesenteries were much ex-
panded in breadth. The parieto-basilar muscles are very weak. The distribution of the mesenteric
muscles on the body-wall is fairly considerable.

The filaments have the usual structure. The glandular tract contains numerous, equally broad
nematocysts with greatly twisted thread (length (34) 38-49 (53) ft, breadth 6 — y ft). I have not observed
any thick nematocysts resembling those found in the lower part of the body-wall, if on the whole
they occur they must be very scarce; in one specimen I have found a single one (length 36/^, breadth
n ft). Further, many thick-walled capsules occur here with distinct basal part to the spiral thread,
broadest in the one end (length about 22 (19 — 24)^, sometimes 26 tt, breadth about 5—6//). The
polyps are dioecious, one of the specimens examined was a male with developed testes.

Systematic remarks. This species is closely related to E. danielsseni, from which it differs
however in external appearance, especially in the form of the coenenchyme and with regard to the
structure and distribution of the nematocysts and the mesenteries. As in E. danielsseni the capsules
in the lower part of the body-wall and in the capitular region are different in this species.

var. nordgaardi PI. 2, fig. 7.

As already pointed out above, the external appearance of E. lindahli is very much like that
of E. erdmanni. At Lyngen Dr. Nordgaard has collected material of a Zoantharia which I determined
as E. erdmanni (Carlgren in Nordgaard. Hydro, and Biol. Invest. 1895, p. 159). Two of the specimens
in the collection I retained for the Riksmuseum in Stockholm. On closer examination, however, it
appeared that the one specimen was not E. erdmanni but a species which must be closely related to

ZOANTIIARIA

23

E. lindahli or identical therewith. But as it differs somewhat from E. lindahli with regard to the
nematocysts, I have for the present set up this species as a variety of E. lindahli , leaving to later
investigations, when more material has been obtained, to prove if it may possibly form a separate
species. I ma}- also mention that among the specimens sent back to Dr. Nordgaard there may
possibly still be found a few specimens of this variety which I have called Nordgaardi. All these
specimens certainly need revision.

Occurrence: 630 37' N., 200 24' E. Lyngen off Kaafjord. 1 sp.

Dimensions: Length 2'i cm., smallest breadth 0-2 cm., greatest breadth 07 cm.

Colour in alcohol: In the lower part gray, in the upper light sand-coloured.

External appearance (fig. 7 PI. 2). The polyp was truncate and somewhat contracted in
the lower part, the upper part being expanded. The distal margin was rounded. The capitular
furrows were very distinct and their number was 20. Tentacles and oesophagus as in the main form.
The mesoglcea of the body-wall was considerably incrusted in the outer part, less in the inner. The
incrustation consisted of sand-grains and some sponge needles. But I have not observed any fora-
minifera, which however are possibly dissolved, as the animal, so far as I remember, had been pre-
served in formaline or formaline spirit.

The anatomical structure seems to agree with that of E. lindahli with the exception regarding
the nematocysts mentioned already. The number of mesenteries was 36, 10 macro- and 8 micro-
mesenteries on either side of the polyp.

The nematocysts are generally larger than in the typical E. lindahli. In the lower part of the
ectoderm of the body-wall there is a fairly frequent occurrence of equally broad nematocysts with
greatly twisted thread (length 43 — 48 p, breadth 10 — 12 fi). In the capitular region large capsules of
the same kind as in the filament occur somewhat frequently (length 38 — 48//, breadth 7 fi).

The ectoderm of the tentacles contains numerous spirocysts, the thick-walled nematocysts
being very scarce (length 17 — 19 (22) fi). Earge nematocyst capsules with greatly twisted thread also
occur here sparsely (length 43—48//, breadth 7 fi), and even sometimes smaller nematocysts of the
same kind as in the filament. The oral disc has, as regards the nematocysts, almost the same struc-
ture as the tentacles.

The oesophagus is provided with numerous, thick-walled capsules about 24 // long and less
than 5 /i broad. Further very few nematocysts with greatly twisted thread occur of the same size and
structure as in the filament.

The glandular tract of the filament contains partly nematocysts with greatly twisted thread,
partly larger ones 43 — 60 u long and j /_t broad, sometimes curved, partly smaller ones generally curved
26— 34/i long and 5// broad; further thick-walled capsules with distinct basal part of the spiral thread
and broader at the one end (length 22 /i, breadth 5//, length 24 — 26^, breadth 6/1 in the broadest end).

Epizoanthus erdmanni (Dan) Hadd. & Shackl.

PI. 1, fig. 14, 16, 17, PI. 2, fig. 24, PI. 4, fig. 3, PI. 5, fig. 4.
Mardoel erdmanni n. sp. Danielssen Norwegian North Atlantic Exped. Actinida 1890 p. 116, PI. 6,

fig. 1, PI. 21, 22, figs. 1 — 7.

24 ZOANTHARIA

Epizoanthus erdmanni (Dan) Haddon & Shackleton Revision British Actiniae 1861 p. 623, 633, 635, 639;
(Dan). Carlgren in Nordgaard Hydrograph. and Biol. Invest. Norweg. Fjord

J905 P- T59-
? Ma in ill if era sp. M. Sars Nyt mag. Nat. 6-2 No. 10 1851 p. 142.

f Zoauthus arctiats n. sp. M. Sars Forh. Skand. Nat. Mode 8. i860 p. 692 Forh. Vid. Selsk. Christiania

i860 p. 144.

? Zoanthus (str. s.) arciiais, Andres Le Attinie 1883 p. 546.

Occurrence: Spitzbergen 8i° 14' N., 22°5o'E., N. E. of Seven I sis. 150 m. gray clay. Bottom
temp. 20 vSpitzb. Ex. 20/8 1898 No. 37 R. M. several specimens.

8o°3'N., 8°28'E. 475 m. clay Bott. temp. ri° 14/8. 1878 N.N. A. E. St. 363 R. M.

Beeren Island 75°3S'N., I3°i8'E 350 m. Bottom temp. 2730 Spitzb. Exped. 1898 1/9 No. 41 R. M.
several spec.

730 3' N., i8°3o'E. 410 m. Bott. temp. 2°. Spitzb. Exp. 4/9 1898 No. 42 R. M. some spec.

73°27'N., 23°ii'E. 460m. black grayish clay Bott. temp. 2-67°. Spitzb. Exped. 12/6 1898 No. 2
R. M. 2 spec.

72°53'N., 2i05i'E. 408 m. clay. Bott. temp. 1-5°. N. N. A. Exp. 30/7 1878 St. 363.

72°27'N., 20°5i'E. 349 m. Sabulous clay, Bott. temp. 3-5°. N. N. A. Ex. y/y 1878 St. 290.

Norway 7o°2'.5 N., 2i°4i/ E. Kvaeuangen 300 — 343 m. Bott. temp. 2-3°. 19/4 1899 Nordgaard R. M.

Altenfjord 80 fins, clay bott. July 1890 Jagerskiold U. U. Z. M.

69°54/N., 20°27'E. Lyngeii between outer Garvik and U16 300m. Nordgaard 3/5 1899. R. M.

Lyngen off the Kaafjord 250m. bott. temp, abeut 2-85° 3/5 1899. Nordgaard R. M.

69°4i/N., i5°5i'E. 1591m. Sabolous clay Bott. temp. 1-2°. N. N. A. E. 7/7 1877 St. 190.

Foldenfjord 530m. 6/4 1900 Nordgaard.

Komagfjord Daniels sen [E. arcficits) Bergens M. (R. M.).

Skatoren Tromso. 40 fms. Tromso M.

Malangen 69°33/N., i8°o' E. 380 m. Bott. temp. 4-1°. Nordgaard 14/4 1899 (R- M-)-

66° 45' N., 150 36' W. 200 m. Bott. temp. 2-39°. 5/8 1900. Michael Sars Ex.

Budderbay 30/6 1884 C. Aurivillius.

Greenland 74°52'N., i7°i6'W. 350 m. clay mud with sand and small stones. 4/7 1899 Greenland
Ex. No. 18.

Iceland Gfjord Moller, 1 colony Copenh. M.

Dimensions: According to Danielssen the polyps in expanded state may reach a length
of 3-5 cm. and a breadth of 2 cm. While considering the first to be very probable, I feel however some
doubt as to whether the breadth can be so great. The specimens examined by me were very variable
in size. The largest polyp (fig. 24 pi. 2) had a length of about 27 cm. and a breadth of o-6 cm. at the
broadest place.

Colour: (Danielssen). "The body is light brownish red almost brick-colour, somewhat
grayish green with a violet play (var. autivittii?). The tentacles lighter coloured, brownish red and
transparent. The oral disc is still lighter in colour than the tentacles and round the outer margin of
the oral disc, exactly at the base of the inner tentacular series, there is a narrow light coloured rose-

ZOANTHARIA 25

red annulus." In the preserved state most of the specimens were dirty-coloured light brown. Some of
the specimens were grayish e. g. those from Altenfjord. The colony taken during the Michael Sars
Expedition was black with incrusted, small, black sand-grains and the colony originating from Iceland
Ofjord was even darker than is generally the case with this species.

The external appearance has been well described by Danielssen, who has also given
some rather good drawings of the external appearance of the colonies. The species forms free, unfixed
colonies of 1 — 6 seldom more polyps connected with each other by a small tube-shaped ccenenchyme,
which is generally so inconsiderable that the polyps seem to grade smoothly over from one to the
other (see fig. 14, 17 PI. I). The more developed polyps are narrow at the base, but expand gradually
towards the distal part, so that the animal has its greatest breadth in the capitular region. The small,
not fullgrowu polyps approach the cylindrical shape. Sometimes the polyps are provided with cross-
furrows, which undoubtedly have only been caused by contraction. The capitular region has generally
quite distinct ridges and furrows. The number of furrows varies considerably according to the size
of the polvps. Danielssen states that the species has 18 capitular furrows, here they vary between
14 and 15 in small specimens and in the large between 16 and 20, and in one polyp I have even
counted up to 22. But generally the majority seem to have 18 furrows. Of 116 specimens 42 had 18
capitular furrows, 26 had 16, 17 had 17, 9 had 19, n had 20 and 1 specimen 22. Of the smaller
specimens 14 polyps had 15 capitular furrows and 5 had 14. On the majority of the small specimens
the capitular furrows were however so indistinct, that the number could not be determined with any
certainty. The body-wall is more or less rough owing to the greater or less incrustation.

The tentacles are arranged as usual and seem to correspond in number with the mesenteries.
The oesophagus is short with a well-marked siphonoglyphe and a fairly long and broad hyposulcus.

The anatomical structure has also been described by Danielssen, but on several points
incorrectly, as e. g. with regard to the arrangement of the mesenteries, which does not differ from that
of the other Zoanthidae. The ciliated streaks on the macromesenteries however have been observed
by Danielssen who gives a comparatively good picture of them (fig. 5, Tab. 22 Danielssen, 1890).
But on the other hand the arrangement of mesenteries and the length of the filaments on fig. 4, Tab. 22
of the same work are not in agreement with the reality. Some anatomical details are also given by
Haddon & Shackleton (1891).

The ectoderm of the body-wall is fairly high, continuous and contains nematocysts with twisted
thread (length 24—30^, breadth 10— 12 /t). They are equally broad and common except in the capitular
region where they are scarce. The ectoderm is provided with a distinct cuticle, on which particles
of detritus are attached. According to the state of contraction of the animal, the mesoglcea may be
thin or very thick, but is several times thicker than the ectoderm. It is provided with fairly numerous
cells with long outshoots, whereas cell-islets only very seldom occur (pi. 5, fig. 4). Sometimes the latter
may be found at the base of insertion of the mesenteries but as a rule they are not present at these
places, a fact I have ascertained by means of a large number of sectioned specimens from different
localities.

Haddon and Shackleton state (1891 p. 635), that on the specimens sent them by Daniels-
sen there was "a well-marked lacuna in the mesoglcea at the base of the insertion of each mesentery."

The Ingolf-Expedition. V. 4. 4

26

ZOANTHARIA

This I have not observed and therefore think it probable, that another species has been concealed in
Danielssen's specimens - - such things have happened before — and been examined by H add on
and Shackle ton. Thus among the specimens of E. erdmanni from St. 42 collected during the
Spitzbergen Expedition 1898 there were many individuals which at first glance resembled E. erdmanni
(fig. 15, PI. 1) but actually did belong to another Epizoauthus species, i. e. E. daniclsscni. Also a
third Epizoanthus, E. beerenislandictts, was dredged at the same time. This latter species has lacunae
at the above-mentioned places. The entoderm is thinner than the ectoderm.

The incrustation consists almost exclusively of sand-grains sometimes interspersed with a few
sponge-needles and foraminifera. Sometimes the incrustation in the mesoglcea is quite inconsiderable,
sometimes it fills up the whole, so that it is very difficult to study the structure of the latter.

The sphincter is not long but strong and in the greater part of its course it covers almost
the whole breadth of the mesoglcea. In transverse sections through the sphincter the meshes are
large whereas the ridges of connective tissue between the muscle meshes are small (PI. 4, fig. 3).

The tentacles have the usual structure. The ectoderm is provided with numerous spirocysts and
scarce thick-walled capsules (length about 17 (14—19)/;). The longitudinal muscles are fairly well-developed.

The ectoderm of the oesophagus is fairly high and elongated. The large nematocysts of the
kind and size seen in the body-wall are scarce or absent, while the thick-walled capsules are numerous
and 19—24// long. The ectoderm of the siphonoglyphe is as usual somewhat lower than that of the
oesophagus, as the mesoglcea is thicker than in the oesophagus.

The number of mesenteries varies between 28 and 40. Of the following 19 specimens

2 specimens had 28 mesenteries (1 spec, was labelled E. arcticns,

Komagfjord; see below).

3

3°

5

— 32

4

- 34

2

- 36

2

■ 38

1

— 40

Thus, the most frequent numbers seem to be 32—34, which corresponds with the most frequent
number of capitular furrows. The specimens with 30, 34 and 38 mesenteries had a few mesenteries
more on the one side than on the other. The micromesenteries are fairly well-developed and project
into the gastric cavity, as long as the main part of the entoderm of the body-wall is high. The
longitudinal muscles of the macro-mesenteries are fairly well-developed, the mesoglcea is thin. The
parieto-basilar muscles are rather weak. The distribution of the longitudinal and the parieto-basilar
muscles on the body-wall is inconsiderable.

Of the proto-mesenteric filaments the shortest are those corresponding to the 6th pair of proto-
mesenteries in Actiniaria, while the others are long. The filaments of the metamesenteries decrease in
length towards the siphonoglyphe. The filaments have the usual structure. Nematocysts with greatly
twisted thread resembling those in the body-wall occur sometimes very scarcely, sometimes more
frequently. They are equally broad and 24—31// long, the breadth being generally 10/z (9-12). The

ZOANTHARIA 27

thick-walled capsules have a distinct basal part to the spiral thread and are somewhat broader at the
one end. They are about 19— 24/i long and of fairly common occurrence.

Both polyps from the colony taken in the Ofjord at Iceland differ from the main form with
regard to the nematocysts of the mesenteries. On maceration, namely, besides the above-mentioned
nematocysts, some egg-shaped capsules occurred, partly larger about 22 yt long and 19 « broad, partly-
smaller, about 14 /u long and n^ broad, both kinds being fairly numerous. On a closer examination
of the rather bad sections of this form, I found however, that these egg-shaped capsules do not lie in
the filaments but inside these, though it is possible that such a foreign capsule may lie in the filaments.
It is at any rate probable, that these nematocysts, just as was the case with some similar capsules in
E. incrustatus , do not belong to the animal but are foreign capsules absorbed by it (see p. 13). It is
worth observing, that the abnormal specimens of £. iiicrusfatus and E. erdmanni originate from almost
the same region.

The species is dioecious.

Remarks: I have here taken Zoanthus arcticus as synonym to E. erdmanni, though I have
not been able to prove the correctness of this assumption, no type-specimens of Z. arcticus being present
seemingly in the Bergen Museum. On the other hand, there are some specimens taken by Daniels-
seu in Komagfjord and determined (by whom?) as Z. arcticus. As far as I am able to see from the
anatomical examination these are no other than E. erdmanni, though they form no colony but are
single specimens. According to the rules of priority, the species should be called E. arcticus and not
E. erdmanni, if the supposition is correct that they may belong to one species. As type-specimens
seem to be wanting, however, and the description of Z. arcticus is fairly poor, it seems advisable to
retain the name E. erdmanni.

Danielsseu states, that E. erdmanni occurs in two forms different as to colour, the one being
darker and the other lighter grayish. Several specimens may even be quite grayish, as e.g. those
from Altenfjord, but otherwise their external appearance does not differ much from that of the others.
On the other hand, from the localities mentioned below there is a more slender form, which in other
respects also differs a little from the main form. This variety has been named var. aurivillii, though
it hardly differs essentially from the main form, grading into this through some transitional forms.

E. erdmanni var. aurivillii.

PI. 2 figs. iS, 28, 29 PI. 5, fig. 5.
Zoanthus Couchi Johnst. C. Aurivillius 1886 p. 52.

Occurrence: Norway Outer part of the Kwsenangfjord 50 — 100 fins. Stone and clay. June
1884 Carl Aurivillius, several specimens Ups. M.

Finmarken Goes & Malmgren R. M. some specimens.

Jagfjord 200m. 18. 2. 1899. Nordgaard 1 colony.

Dimensions: Length of the largest polyp: 17 cm., greatest breadth 0-4 cm.

Colour light grayish, in the distal end reddish (Aurivillius) in alcohol: light grayish.

External appearance: the polyps are either separate, or form colonies connected by a small
tube-shaped ccenenchvme as in the main form. The number of polyps in the colonies is variable, the

23 ZOANTHARIA

greatest number observed being 7. The polyps are arranged in the same way as in the main form,
but they are considerably more slender and narrower in comparison with the length than in the main
form. As in the latter they are narrow at the base but expand gradually towards the distal part.
The capitular region, which was contracted in most of the specimens, had distinct capitular furrows
varying in number between 14 and 19 - - 2 polyps had 14, 4 had 15, 13 had 16, 1 polyp 17 and
another 19 furrows — the maximum frequently being thus 16. The preserved specimens had often more
or less distinct cross-furrows. The tentacles were much narrower than in the main form. The oesophagus
is short, the siphonoglyphe distinct, hyposulcus well-developed, though shorter than the oesophagus.

Anatomical description. The ectoderm is fairly high, continuous and contains few nema-
tocysts or none. The mesoglcea is several times thicker than the ectoderm and like this is richly
incrusted with sand-grains, which make the anatomical examination difficult. As the incrustation is
not very strong, however, I have been able to make out, that the mesoglcea contains a few, large
cell-islets but numerous cells (and small cell-islets). (PI. 5 fig. 5).

The sphincter is strong. Seen in transverse sections through the sphincter the mesoglceal
meshes are however fairly large.

The ectoderm of the tentacles is of the typical structure with very numerous spirocysts and
fairly common thick-walled nematocysts (length 17/1).

The ectoderm of the oesophagus is high. There is a frequent occurrence of equally broad
nematocysts with twisted thread (length 24— 36/i, breadth 10—11/2) and of thick-walled nematocysts
(length 22 — 25/./). The mesoglcea is thin, in the lower part it forms longitudinal ridges corresponding
to the insertions of the mesenteries. The ectoderm of the siphonoglyphe is as usual thinner than in
the oesophagus, the mesoglcea on the other hand is several times thicker than there. In two specimens
the number of mesenteries was 32, in a third 30. At least one of the first-mentioned polyps had
the normal number of developed mesenteries. The third had 9 macro and 7 micro on the one side and
8 macro and 6 micro-mesenteries on the other. The micro-mesenteries are fairly well-developed and
from the oesophageal region they reach somewhat into the chambers. The longitudinal muscles are
strong, especially on the directive mesenteries. The folds are however large. The parieto-basilar muscles
are very weak. Moderate distribution of the longitudinal and parieto-basilar muscles on the body-wall.

The filaments have the usual structure. The glandular tract contains numerous capsules, some
equally broad with greatly twisted thread (length 26 — 34^, breadth ioju), others thick-walled capsules
broader at the one end and with distinct base to the spiral thread (length 19 — 22 /i).

The sexual organs were not developed in the specimens examined by me.

Epizoanthus danielsseni 11. sp.

PI. 1 fig. 13, 15 PI. 2 fig. 6 PI. 5 fig. 1.

Epizoanthus glacialis n. sp. pro parte Danielssen Norwegian N. Atlantic Ex. p. 129 fig. 9. PI. 6.

Occurrence: 64°2i/N., io°4o'E. Sabulous clay. Bottom temp. — 070 Norwegian North Atl.
Ex. Stat. 164 June 29th 1879. 5 SP- Bergens Museum, (sp. a).

ZOANTHARIA 29

73°3'N-i i8°3o'E. Beeren Island— Norway 410 in. Bolt. temp. 2°. Gray clay. Spitzbergen Ex. 1898
4/9 No. 42 several colonies R. M. (sp. b).

Davis Straits 80 fms. 20/10.1884. Holm, several colonies. Copenh. Museum, (sp. c).

750 26' N., 67°27' W. 260 fms. Sophia Ex. No. 582. 1 sp. R. M. (sp. d) var. loveni Finmarkeu.
0xfjord Loven. 1 colony. R. M.

Dimensions: (a) Length of the largest polyp o\S cm., breadth 07 cm., (b) length of the largest
polyp 1 cm., breadth 07 cm. (c) length and breadth about 0-5 cm. (d) height 08 cm., breadth o-6 cm.

Colour. According to Danielssen's figure 9 PL 6, which I consider to represent this species,
the body-wall must be light-red with a yellowish tint, the latter being due to the large amount of
sand in the incrustation. The capitular furrows are reddish, with a tinge of brown. The tentacles
and the oral disc (the central part in the middle?) are reddish brown. In alcohol a, c and d are light
sand-coloured, b dirty grayish.

External appearance. The polyps from the localities a and d formed no colonies and were
fixed on stones, whereas most of the specimens from b and c generally formed colonies; c was fixed
011 Balani, b on stones and Rhizopoda (Rhizammina?). The polyps are seldom placed quite close
together; the ccenenchyme between the different polyps is generally fairly well-developed, but very
thin. On a colony from c and on those from b, when viewed externally, it looks as if the ccenenchyme
is thick. This is generally not the case, however, though the irregular under-layer of tubuli pressed
together makes it look thickened at some places. All the polyps were contracted and the tentacles
not to be seen; in this state the breadth and the length are almost equal or the length a little greater.
The distal part is somewhat broader than the proximal. On most of the polyps the upper aspect is
truncate1, sometimes they are a little rounded, especially the smaller polyps. The capitular furrows
are more or less distinct, most distinct in d (fig. 13), in the smaller specimens their number could not
be determined. They seem to vary between 16 and 22, a) 22, b) 18, 18—16, 16, 17, 21—18 — 17 — 18,
c) 20—20 — 22 — 22, d) 18. The polyps as well as the ccenenchyme were strongly incrusted with sand-
grains, which made the sectioning very difficult.

In a closely examined specimen the number of tentacles was 36. If the tentacles are double
the number of capitular furrows, they must vary between 32 and 44.

The oesophagus is short with distinct siphonoglyphe and a hyposulcus which is as long as the
oesophagus.

Anatomical description. The ectoderm of the body-wall is fairly high and continuous
with a weak cuticle. In the lower part of the polyp are equally broad nematocysts with greatly
twisted thread (length 34—41^, breadth n — 12 ;i). In the capitular region we find similar capsules,
which are however considerably narrower (length 34 — 41 ft, breadth 7 fi). The mesoglcea is very large,
at least twice as thick as the ectoderm and is generally strongly incrusted with sand and some fora-

1 Among the specimens of Epizoanthus glacialis collected by the Norwegian Xorth Atlantic Expedition were also
some polyps of E. dauielsseni. Danielssen 1891 p. 130 says that "when the polyp (of E. glacialis) is retracted the uppermost
extremity appears truncated but with a little depression in the middle and a rounded margin carrying it PI. 6, fig. 9." This
description agrees well with a polyp found in the collection which I consider to be the original of Danielssen's fig. 9, PI. 6 —
represented in my paper in fig. 6 PI. 2. This polyp belonged to the species E. danielsseni. The description of the upper
part of the body 011 the other hand does not agree with E. glacialis.

3°

ZOANTHARIA

niiiiifera. It contains fairly many small cells with outshoots (PI. 5, fig. 1). In the specimen from the
locality c, which was somewhat less incrusted than the rest, there seemed to be a sparse occurrence
of cell-islets of moderate size near the entoderm. Whether these may aiso be found in the other
colonies I am unable to say owing to the strong incrustation. The ectoderm is almost as high as
the entoderm.

The sphincter is very strong and resembles that of E. glacialis. It almost fills up the whole
breadth of the mesoglcea. In transverse sections we find large muscle fibres separated by fairly thin
mesoglcea-ridges, which divide up forming smaller meshes.

The tentacles have the usual structure. The ectoderm is provided with very numerous spirocysts.
It contains besides many small nematocysts of the same kind and size as in the capitular region and
typical thick-walled capsules (length 17— 19 /u).

The ectoderm of the oesophagus is high and contains numerous thick-walled capsules with
fairly distinct basal part to the spiral thread (length 24—27/;). There is besides a sparse occurrence
of large nematocysts as in the capitular region (length 38 — 48 p, breadth j ji). The mesoglcea is thin,
but thickened in the siphonoglyphe.

The number of mesenteries is variable. In two of the polyps of b it was 38 and 32 respectively,
typically developed in the latter and in the first with two mesenteries more on the one side of the
sagittal plane than on the other. One specimen from a had 36 mesenteries and 2 specimens from c
had 36 and 30 respectively. The latter was however a small polyp.

The macro-mesenteries are large with thick mesoglcea (all the specimens were however strongly
contracted). In the lower part of the oesophagus the micro-mesenteries were fairly weak and only
projected very little above the entoderm of the body-wall. The longitudinal musculature is comparatively
strong and when seen in transverse section lies in close folds. The parieto-basilar muscles are weak.
The longitudinal and the parieto-basilar muscles extend a long way onto the body-wall.

The filaments have the usual structure. In the glandular tract there is a numerous occurrence
of nematocysts with greatly twisted thread (length 34—48//, breadth 7//, sometimes 8/i) and thick-walled
capsules with distinct basal part to the spiral thread, broader at the one end than at the other (length
22 /i). Further, I have sometimes observed some very scarce nematocysts of the same kind as in the
lower part of the body-wall (length (24) 26 — 29//).
The polyps are dioecious,
var. loveni PI. 2, fig. 9.

Together with the species E. glacialis and Isozoantlnts ingolfi collected by Sven Loven in
Oxfjord in Fiumarkeu, occurred a small colony with 2 polyps (fig. 9 PI. 2), which had a great outward
resemblance to these species and a similar incrustation of sand-grains, among which a number of black.
Examination of the nematocysts and the subsequent anatomical investigation showed, however, that
they did not belong to these species but stood in better agreement with E. daniclsscni, to which I
provisionally refer them, though they are not in absolute agreement with this species, measurements
especially of the large nematocysts, with regard to length, lie somewhat below the values found in
E. daniclsscni (even among the specimens from locality c which showed the lowest values). The
incrustation is also considerably weaker, so that we may possibly have a new species before us, but

ZOANTHARIA 3 I

as the material is so small and not very well-preserved, I have preferred to consider this colony as a
variety of E. danielsseni, the more so as the anatomical investigation is incomplete.

Dimensions of the largest polyp: length 04 cm., breadth in the capitular region 0-45 cm.

Colour iii alcohol : grayish with black sand-grains.

External appearance: the polyps were cylindrical, broader in the capitular region. The
distal margin is truncate, the upper part sunken. The capitular furrows are indistinct. The incrustation
was not so strong as in the main form and mainly restricted to the outer part of the mesoglcea.

Anatomical description. Regarding the inner structure the lower part of the body-wall
contains in the ectoderm numerous nematocysts with greatly twisted thread (length 24—36//, breadth
11 — 12//), in the capitular region similar capsules often occur (length 29 — 31 ft, breadth only 7 ft).

The sphincter was very strong, resembling that in the main form, but not drawn out so much
as in the latter.

The ectoderm of the tentacles contains numerous spirocysts, fairly many nematocysts of the
same kind as hi the capitulum (length 31 — 36/*, breadth y ft) and a few thick-walled capsules (length
14—17//). Similar capsules are also found in the oral disc.

The oesophagus contains numerous narrow, thick-walled nematocysts (length 19—22//). I cannot
determine the number of mesenteries with any certainty, but it must be about 32 or a little more.

The glandular tract of the filament is provided with very few, uniformly broad capsules of
the same kind as in the lower part of the body-wall (length 29—36//, breadth 12 ft) and with many
capsules like those in the capitular region (length 29—38//, breadth y ft). Further, many thick-walled,
narrow nematocyst capsules occur (length 19—22//) and thick-walled capsules with distinct basal part
to the spiral thread, which are broader at the one end (length about 19//).

Epizoanthus roseus Dan.

PI. 3, fig. 4, PL 5, fig- 6.

Epizoanthus roseus n. sp. Dauielssen Norwegian North Atl. Ex. 1890. Actinida Tab. 6 fig. 10 Tab. 25

figs. 4—6.

Occurrence: 7i025'N., i5°4i' E. clay 1134 m. Bott temp. ro. Norw.-North Atl. Ex. 1877
19.7 B. M. R. M.

Dimensions. The polyps reach a length of up to 15mm. (Danielssen). In the preserved
state the length of the largest polyp was about n cm., largest diameter a little under the tentacles
0-5 cm., smallest diameter 03 cm.

Colour. "The sarcosoma is semi-transparent, grayish. The polyp is grayish-yellow owing to
the incrusted sand, but the rose-red integument shines through. The oral disc is rose-red with lighter-
coloured radii. The tentacles are, upon their lowest broad part rose-red like the oral disc, but upon
their superior half are paler in colour and almost white at the point" (Danielssen). In the preserved
state they are dirty sand-coloured.

External appearance. The polyps are connected with each other by a flat coeuenchyma
of moderate size. The single polyps are placed quite close to each other. With regard to shape the

,2 ZOANTHARIA

polyps according to Danielssen are "almost piriform." The small contracted polyps with quite
retracted tentacles are somewhat narrower in the proximal than in the distal part, which is somewhat
rounded. The expanded polyp was narrowest a little above the base, then gradually becoming wider
and reaching its greatest breadth some way below the tentacles, afterwards tapering a little towards
the base of the tentacles. The distal part is provided with capitular furrows, which Danielssen
states to be 12 in number. This is too few, as far as I can see. The ridges and furrows are certainly
not so distinct in the preserved polyp, but I have found 16 — 18. The polyps are incrusted with sand-
grains, especially in the proximal part and in the ccenenchyme.

The number of tentacles probably agrees with the number of mesenteries.

The oesophagus has a very distinct siphonoglyphe.

Anatomical description. The ectoderm of the body-wall is fairly thin, considerably thinner
than in E. glacialis , continuous and provided with a thin cuticle. In the ectoderm are fairly many
spirocysts (normal shape?) and large uematocysts with greatly twisted thread. The latter have a length
of 29—31 fi and a breadth of 12 fi (the lower part being broader than the upper). Small cells occur
in great numbers, but no lacunae or groups of cells seem to be present in the mesoglcea, at least not
in the distal part (PI. 5, fig. 6). The incrustation is fairly strong and consists of comparatively large
sand-grains, here and there a sponge-needle and exceptionally foraminifera. The entoderm is well-
developed and thicker than the ectoderm.

The sphincter is mesoglceal but not so strong as in the other Epizoanthus-species examined
by me (PI. 3, fig. 4). In the distal part the meshes are considerably larger than in the proximal and
extend horizontally, i. e. in the direction from the ectoderm to the entoderm. The bridges of connective
tissue between the muscle-meshes were broad.

The tentacles have the usual structure. The ectoderm is very high with numerous large
spirocysts; further, it contains the same kind of large uematocysts as occur in the body-wall and typical
thick-walled capsules (length 17^). The mesoglcea is thin, the longitudinal musculature moderately
developed.

The ectoderm of the oesophagus is fairly thick and contains large capsules, almost of the same
kind and size as those in the body-wall, besides not a few typical thick-walled capsules (length 24 — 26/;)
The mesoglcea is thin, being howrever considerably thickened in the siphonoglyphe.

The single specimen examined by me had 32 regularly arranged mesenteries. Danielssen 's
statements on this matter cannot be correct, as it is quite evident from his figure, that he has not
seen the macro-type arrangement but has supposed the macro and micro-mesenteries to be alternating
everywhere. The mesoglcea of the macro-mesenteries is fairly thick, the micro-mesenteries rather long
but narrow and not much developed. The musculature is comparatively weak.

The filaments seem to have the usual structure. The glandular tract contains the same kind
of uematocysts as occur in the oesophagus. The thick-walled capsules may sometimes be a little
smaller (22—24//).

The sexual organs were not developed in the polyp closely examined by me.

ZOANTHARIA 33

Epizoanthus beeren-islandicus n. sp.

PI. 2, fig. 10, PI. 3, fig. 2, PI. 4, fig. 1.

Occurrence: 730 3' N., i8°3o' E. Beeren Island-Norway 410 m. Bott. temp. 2°. Gray clay. Spitz-
bergen Exp. 189S 4/9. No. 42 3 sp. R. M.

Dimensions of the largest polyp: height and breadth about 1 em.

Colour in alcohol: yellowish.

External appearance. The three specimens of this species formed no colonies. One
was attached to a stone, one other to a Retepora. The eeeneuchyine was very thin, disc-shaped.
The polyps are cylindrical, almost as high as broad -- the animals however were very contracted -
and the distal part was a little broader than the proximal. The upper margin was truncate on the
contracted polyps. The capitular region has some fairly distinct furrows. In the large specimens I
counted 21 capitular furrows with distinct, incrusted ridges between them. The incrustation, which is
comparatively inconsiderable, consists of small light sand-grains, now and then interspersed with a few
small black sand-grains.

The oesophagus is short with distinct siphonoglyphe and hyposuleus of almost the same length
as the oesophagus.

Anatomical description based on two specimens. The ectoderm of the body-wall is con-
tinuous and provided with a distinct cuticle. It is fairly high and contains uematocysts with greatly
twisted thread, which are uniformly broad, 31—37^ long and n — 12/^ broad, and fairly common except
in the capitular region. The mesoglaja is always thicker than the ectoderm, double as thick at the
most. It contains fairly many small cells with long thread-shaped outshoots, here and there cell-islets
and lacunae. The latter often, though not always, lie at the base of the mesenteries, so that in certain
sections (PI. 4, fig. 1) the lacunae are very characteristic in appearance. The entoderm is almost of the
same size as the ectoderm. The incrustation is rather inconsiderable in the ectoderm; the greater part
of the mesoglcea has no incrustation, this is mostly found near the mesenteries from which it often
penetrates into the above-mentioned lacunae.

The sphincter is strong and long (PI. 3, fig. 2) and lies nearer the ecto- than the entoderm, so
that in the capitular furrows it is only separated from the ectoderm, by a thin mesoglceal lamella.
The muscle-meshes are drawn out crosswise and the mesoglceal meshes are thin.

The ectoderm of the tentacles contains as usual numerous spirocysts, whereas the thick-walled
uematocysts (length 17 p.) are very scarce. Furth er, there is a very sparse occurrence of the same
large uematocysts as found in the filaments. The ectodermal musculature is fairly stroug.

The ectoderm of the oesophagus contains fairly many large nematocysts (length 34—41 11) and
numerous typical, thick-walled capsules (length 22—25,0). The structure of the siphonoglyphe agrees
with that in other species of Zoanthidae described here.

The number of mesenteries in the three specimens was 44, 40 and 39 respectively. In the first
specimen, which was regularly developed, the 6th proto-mesentery on the one side of the sagittal plane
was a micro instead of a macro-mesentery. In the second specimen the one side was more developed
and had one pair of mesenteries more than the other. The micro-mesenteries in the lower part of

The Ingolf-Expedition. V. 4. 5

,, ZOANTHARIA

tlie oesophageal region were fairly well developed. The longitudinal muscles on the niaero-raeseuteries
are fairly strong but form few folds. The parieto-basilar muscles are very weak and narrow. The
distribution of the longitudinal and parieto-basilar muscles on the body-wall is quite distinct.

The filaments have the usual structure. The nematocysts of the glandular tract are 34 — 41 ji
long and 10 — 12 p broad (very seldom only 9/z broad). They are uniformly broad and very common
and there is also a frequent occurrence of thick-walled capsules with distinct basal part to the spiral
thread (length 22—26//).

The sexual organs were undeveloped in the two specimens sectioned in the sexual region.

Epizoanthus glacialis Dan.

PI. 2 fig. 1—5, PI. 4 fig. 2, 6, 7.

Epizoanthus glacialis 11. sp. Danielssen Norw. Atl. Exp. Actinida p. 129, Tab. 6 figs. 7—9, Tab. 24

figs. 5 — 8, Tab. 25 figs. 1 — 3 pro parte.
Palythoa norvegica Kor. & Dan. Mareuzeller K. Acad. Wiss. Wien 3 1886. IV p. 16 vox Jan. mayeni.

Occurrence: 68°2i'N., io°4o'E. 836111. Sabulous clay. Bott. temp. — 07°. Norw. North Atl.
Ex. 1876, 29. 6. St. 164. many specimens Bergen M.

7i°25'N., i5°4i'E. 1134111. Clay. Bott. temp. — 1-0°. North Atl. Ex. 1877. 17.7 St. 200. a few
specimens B. M.

Altenfjord 80 fins. clay. June 1890. J agerski old. some colonies Upsala M., R. M.

Oxfjord Finmarken. Love 11 1 sp. R. M.

Greenland Umauak 250 fms. clay Amundsen 15.8. i860, several specimens R. M.

Greenland Umanak 397 fms. light clay. Ingegerd and Gladans Ex. J. Liudahl 13.7. 1871. 2
specimens R. M.

Greenland off Umanakfjord 122 fms. hard light grayish clay. Ingegerd and Gladans Ex. J. Liu-
dahl 14.7. 1871. several large colonies R. M.

Greenland 7o°53'N., 520 18' W. 397 fms. light clay. Bott. temp. —2-8° (270 F.) C. Ny strom
Upsala M.

Jan Mayen 200111. Austrian polar stations 1882 — 1883. 1 colony: var Jan mayeni.

Dimensions. The column measures about 2'ocni. in height, 06cm. in breadth at the base,
06 — 07cm. broad at the uppermost extremity and 0-40111. broad at the middle (Danielssen). Spec-
imens from Umanak fjord, which were considerably larger than the specimens of E. glacialis I have
seen from the Norwegian North Atlantic Expedition, had in the preserved state a length of about
i-8 cm. and a breadth of o-6 cm., the smallest breadth being 04 cm.

Colour. The incrusted portion of the body is greenish-yellow but when the animal is extended
almost yellow, having a somewhat greenish play of colour at the base only. The oral disc is faint
brick-red with darker folds round the oral aperture. The tentacles are more intensely red than the
oral disc, but are somewhat paler in colour at the extremities (Danielssen). In alcohol dirty
yellowish.

ZOANTHARIA 35

External appearance. This species forms larger or smaller colonies, sometimes almost of
the size of a hand (the colonies dredged off Umenak Fjord). The polyps are connected with each
other by a flat, rather thick cccnenchyme with a fairly well developed net-work of entodermal canals.
The polyps are either placed close to each other as in the Umenak material or emerge from the
cccnenchyme at greater intervals. They are cylindrical in shape especially in the longitudinally expanded
specimens, in the more contracted the middle part becomes somewhat narrower than the capitular
region especially. The length is generally at least double the breadth. On contracted polyps the distal
margin is rounded not truncate. Danielssen states however that "when the polyp is retracted the
uppermost extremity appears truncated but with a little depression in the middle." As far as I can
see, this is not the case but a specimen of E. danielsseni found in the same sample as E. glacialis had
this shape, so that Danielssen's description was probably in this regard taken from that species (cf.
E. danielsseni). The capitular furrows are distinct and vary in number. The greatest number observed
by me was 28 the smallest 16, the latter in a small specimen. The polyps taken near the coast of
Greenland, which generally were considerably larger than the Norwegian ones, had also as a rule a
larger number of capitular furrows. In 15 of the first named specimens I counted the following number
of capitular furrows 20, 20, 20, 20, 20, 21, 21, 22, 23, 23, 23, 25, 27, 28. Five type specimens had 16, 18, 18,
20, 20. Specimens from Altenfjord have 17, 17, 18, 18, 20, 20, 20, capitular furrows. That the number of
furrows may also be high in the Norwegian forms may be seen from the fact, that I found among
them a specimen with no less than 52 mesenteries. The incrustation, which consists almost exclusively
of sand interspersed with a few sponge-needles, is not very strong and restricted to the ectoderm and
the outer part of the mesoglcea. The oesophagus has the usual appearance lengthwise. The siphouoglyphe
is distinct with a well-marked, though not very long hyposulcus.

Anatomical description. The ectoderm of the body-wall is high and sometimes as thick
as the mesoglcea; it is continuous, but may at times show a slight tendency to become discontinuous,
and is provided with a thin cuticle. The nematocysts of the ectoderm consist partly of large nema-
tocysts with greatly twisted thread (length 26—34^, breadth 10 — 12//) partly of thick-walled capsules
(length 19/O, which however occur in small quantities.

The mesoglcea is thick, sometimes thicker on one side than on the other. In the distal part
it contains fairly many cells, often provided with long outshoots (PI. 4, fig. 6). Further, there is a
sparse occurrence of cell-islets of moderate size, which however are more numerous in the Umanak
specimens. In the proximal part both cells and cell-islets occur more frequently (PI. 4, fig. 7). No
muscles are present in the mesoglcea except the sphincter and the mesoglceal muscles of the body-wall
which may break through the mesenteries; the structures (muscle-meshes) observed by Danielssen
are nothing but breaches in the mesogloja. Lacunae are absent, except in the sexual region, where
some signs of these are seen. The entoderm is remarkably well-developed in comparison with the
other layers of the body.

The sphincter (pi. 4 fig. 2) is very strong. Seen in transverse section the muscle-meshes in the
proximal part are separated by large portions of mesoglcea, in the distal part they are divided into
large meshes, extending in the direction from within outwards and almost filling the whole breadth of
the mesoglcea, or even more split up here, though smaller and lying nearer the ectoderm than the entoderm

5*

36

ZOANTHARIA

The tentacles have the usual structure. The spirocysts in the ectoderm are as usual very
numerous, the thick-walled ones (17 — 22, 19—24 pt long) scarce. Further, some large nematocysts of
the same kind as in the body-wall occur in very small quantities. The longitudinal musculature is
moderately developed.

The ectoderm of the oesophagus is high. It contains fairly great numbers of nematocysts partly
large with much coiled thread and uniformly broad, length (26) 29 — 36^, breadth about 12 /*, partly
thick-walled 19 — 24 n long. The mesoglcea is thin but that of the siphonoglyphe on the other hand is
considerably thickened. The ectoderm of the siphonoglyphe is as usual thinner than in the oeso-
phageal region.

The number of mesenteries varies according to the size of the polyps, 3 of the examined Umenak
specimens had 40, 46 and 50 mesenteries. The arrangement of the mesenteries in the first polyp was
typical, both the others had a pair of mesenteries more on the one side of the directive chamber
than the other. One of the type specimens (the smallest) had 36, another 40 and a third no less than
52 mesenteries. While the first and last polyp were symmetrical the third one was very asymmetrical,
the one side having 22, the other no more than 18 mesenteries. Specimens from Oxfjord Finmarken
had 36 mesenteries. Danielssen's statement that the number of micro-mesenteries is the same as
the number of macro-mesenteries is of course incorrect, as Zoanthidae-species with the mesenteries
arranged according to the macro-type do not have as many micro as macro-mesenteries.

In the oesophageal region the macro-mesenteries are fairly thick with well-developed mesoglcea.
The longitudinal musculature is strong with fairly many folds (text-fig. 5). The parieto-basilar muscles
are weak. Extension of the longitudinal and parieto-basilar muscles onto the body-wall inconsiderable.
In the sexual region the macro-mesenteries are thin and the musculature weak. The micro-mesenteries
are moderately developed.

The structure of the filaments is as usual. The glandular tract sometimes contains greater
sometimes smaller numbers of large, uniformly broad nematocysts with much coiled thread — length
(26) 29—36// breadth 10 — 13^ -- and thick-walled capsules 19 — 26// long with distinct basal part to
the spiral thread.

The species is dioecious.

Systematic remarks. In the sample from St. 164 Norw. North Atl. Ex., — the only type-
specimens of E. glacialis which I have had for examination, — there were two species which have
undoubtedly been mixed in Danielssen's description. The one is the species described here, which
I have considered the type-specimen of Danielssen's species glacialis, as his description, at any
rate with regard to the external appearance, may in the main be referred to this species. Figures 7
and 8 on PI. 6 in Danielssen's work evidently represent the above-described species and the same
is certainly the case with fig. 5 and probably also with fig. 6 on PL 24. On the other hand, fig. 9
PI. 6 probably represents E. danielsseni. With regard to the anatomical figures of E. glacialis in Da-
nielssen's work they are so poor that they may represent the one as well as the other of the species,
though the weak incrustation seems to indicate the species I have described as glacialis. Both species
are namely so unlike each other, not only with regard to the nematocysts but also in external

ZOANTHARIA

37

appearance and inner structure, that there can be no doubt that they represent 2 species quite different
from each other.

var. fan mayeni PI. 2 fig. 2.

Through the kindness of Prof. Marenzeller, I have had the opportunity of examining the
specimens from Jan Mayen which he considered Palythoa norvcgica. They could not be referred to
this species with absolute certainty, but may well be considered as a variety of E. glactalis, from which
they differ but little, mostly with regard to the uematocysts which are generally somewhat larger than
in the main form.

Occurrence. See above under the main form.

Dimensions. Length of the largest polyp r2 cm., breadth in the capitular region 07 cm.

Colour in alcohol. Ectoderm uncoloured. Mesoglcea interspersed with black sand-grains.

External appearance. 1 colony consisting
of 2 polyps, which lie close to each other projecting
from a thin ccenenchyme (fig. 2 PL 2). In the con-
tracted state the polyps are elongated , cylindrical
somewhat broader at the upper end and with rounded
capitular region. The capitular furrows are very
distinct, in the smaller specimen I counted 21, in the
larger 24. The siphonoglyphe is well developed.

Anatomical description. The ectoderm

of the body-wall is continuous, very high and thicker

Text-fig. 5. Transverse section through the body-wall with
than the mesoglcea, in which we frequently find broad adjacent mesenteries and oesophagus of Epizoanthus glaciate

uematocysts with greatly twisted thread (length 34-36/A (sPec"™^ dredged by C Nys tr 6 m). Mesoglcea and

J ° J ' muscles black. Ectoderm not drawn and entoderm only

breadth 12 — 13//). Incrustation of small Saud-graillS. in part, dc directive chamber. In the mesoglcea of the

.... . bodv-wall the incrustations are marked bv dots.

Otherwise like the main form.

While the spirocysts in the ectoderm of the tentacles were very numerous, the thick-walled
capsules only occurred in small numbers (length 24//).

The ectoderm of the oesophagus has the typical appearance. The large nematocysts resembling
those in the body-wall are scarce but somewhat larger than usual (length 38— 43 /a breadth 12—13//),
the thick-walled nematocyst capsules are numerous and longer than in the main form — 26—29

The mesenteries. The specimen examined has 42 mesenteries, 12 macro and 10 micro on the
one side, 11 macro and 9 micro on the other. Of the latter the 1st proto-mesentery (according to the
developmental scheme adopted) was not much developed and very little larger than a micro-mesentery.
Otherwise the mesenteries are as in the main form.

In the glandular tract occur some large uematocysts with much coiled thread (length 34—36//
breadth 13//). Further, it contains fairly many thick-walled capsules with distinct basal part to the
spiral thread (length 27—30//, breadth 6//).

38

ZOANTHARIA

Epizoanthus koreni n. sp.

PI. 2 fig. 23, PI. 4 fig. 4.

Occurrence: 62°49' N., 7°i2' W. 276 fms. Bott. temp. r6°. Ingolf Ex. St. 144 1 colony of
two polyps.

Dimensions: Length of the largest polyp ri cm; smallest breadth 0-35 cm.; largest breadth
0-55 cm.

Colour in alcohol: dirty sand-coloured.

External appearance. The ccenenchyme was large and covered among other things an
arm of an Ophiurid. It is fairly thin but has a very robust appearance, probably owing to the imbedded
small foreign particles on which it grows. The 2 polyps are not close to each other but separated by
a fairly great interval. The largest polyp is elongated, almost double as long as broad, narrow at the
base but gradually increasing in breadth upwards. The smaller polyp on the other hand is higher
than broad and more cylindrical. The capitular furrows are distinct, in the largest specimen their
number was 18, in the smaller probably 15. The upper margin of the polyps is truncate, the tentacles
being retracted. The incrustation is inconsiderable and restricted to the outer part of the body-wall.

The oesophagus is short, siphonoglyphe and hyposulcus distinct.

Anatomical description. The ectoderm of the body-wall is fairly high, continuous and
incrusted with sand-grains, sponge-needles and foraminifera , though not very strongly. It is also
incrusted with detritus particles attached to the cuticle. The ectoderm frequently contains nematocysts
with coiled thread, in the capitular region these are scarce. They are uniformly broad 26 — 29 it long,
about 10 /x broad and rounded at both ends. The mesoglcea is thick and considerably thicker than
the ectoderm; only the outer part of the mesoglcca has a slight incrustation consisting of the above-
mentioned particles. The mesoglcca contains numerous oval or round cells and fairly many, middle-
sized cell-islets, and rarely large cavities filled with round or oval cells, the nature of which I have
not been able to determine with certainty (PI. 4, fig. 4 ml?). The entoderm is fairly large and seems to
contain zooxanthellse , which however are more numerous in the entoderm of the oesophagus and the
mesenteries. In the mesoglcea of the mesenteries similar cavities filled with cells may also occur as
in the mesogloca of the body-wall.

The sphincter is very strong and resembles the sphincter in E. erdmanni. It lies considerably
nearer to the ectoderm than the entoderm.

The ectoderm of the tentacles contains great numbers of spirocysts but only few thick-walled
capsules (length about 19/^) and nematocysts with much coiled thread (length 26—31^, breadth io/<).

The oesophagus has the usual structure. I have not been able to make any macerated prepara-
tions of the high ectoderm. The siphonoglyphe is deep with thinner ectoderm and considerable thicker
mesoglcea than in the oesophagus.

In the specimens examined anatomically the number of mesenteries (in the large polyp) was
36, 10 macro and 8 micro on either side of the directive line. The micro-mesenteries are moderately
developed, the macro-mesenteries strong. The longitudinal musculature on the macro-mesenteries is
fairly strong, but not much folded, the parieto-basilar musculature is weak. The distribution of the
longitudinal and parieto-basilar musculature on the body-wall is inconsiderable.

7.0ANTHARIA

39

The filaments have the usual structure. The glandular tract contains numerous nematocysts
with much coiled thread 26 — 36 (i long and 10 — 12 ft broad, sometimes even narrower. Further, some
thick-walled capsules are found (length 19—22/^).

The colony was not sexually ripe.

Genus Isozoanthus Carlgren.

Isozoanthus n. gen. Carlgren in Nordgaard Hydrogr. and Biol. Iuvestig. 1905 p. 159.

Macrocnemic Zoantheae with a diffuse entodermal sphincter muscle. The body-wall incrusted.
The ectoderm is always continuous. Cell-islets and lacunae in the mesoglcea but no encircling sinus.
Dioecious polyps. Polyps solitary or in small clusters, as a rule connected with a comparatively thin
cojuenchyme.

The genus, which has been briefly characterised by me on an earlier occasion (1905 p. 159),
forms a link between the genera Epizoanthus and Parazoanthus. With regard to the appearance of
the sphincter, Isozoanthus agrees with the latter, but in the structure of the body-wall it agrees with
the former. In the genus Isozoanthus the encircling sinus so characteristic of Parazoanthus is wanting.

If attention is only paid to the appearance of the sphincter in arranging the genera within the
macrocnemic Zoauthidae, the Isozoanthus-species would have to be referred to the older genus Para-
zoanthus, but if the structure of the mesogkua of the body-wall is considered to be of some importance
in the characterisation of the genera, it is most reasonable to let the species, which have no iucircling
sinus but are otherwise in the main in agreement with Parazoanthus, form a separate genus, i. e.
Isozoanthus. In the latter case the diagnosis given by Had don and Shackle ton for the genus
Parazoanthus would need no revision, in the first case on the other hand their diagnosis would have
to be altered with regard to the encircling sinus, as for example "encircling sinus absent or present."
If the species comprised by me under the genus Isozoanthus are referred to the genus Parazoanthus.
it would at any rate be advisable to let them form a separate sub-genus named Isozoanthus. Future
investigations must decide, whether Isozoanthus should be considered a separate genus or a sub-genus.

The type for the genus Isozoanthus is Isozoaufhus (Epizoanthus) arboresceus (Dan.). Another
species, by the way the longest Zoantharia known, has been figure by me in Chun's work: "Aus
den Tiefen des Weltmeeres" 2 Aufl. 1905 p. 520. It has been dredged on the Agulhas Bank during
the German deep-sea expedition and provisionally named by me I. gigantcus. The genus thus occurs
in northern as well as in southern seas. A revision of the Zoauthidae already described would pos-
sibly show, that certain forms described as Parazoauthus should in reality be referred to Isozoanthus.

Of the 9 Isozoanthus-species mentioned here only one, namely the type of the genus, /. arbo-
resceus, has been described before by Danielssen, who referred it to the genus Epizoanthus. Da-
nielssen's anatomical description leaves much to be desired in many respects. All the species with
exception of /. danicus have been dredged during the Ingolf Expedition. /. danicus has been takeu
in the Limfjord and determined by Mortensen (1897) as Z. couchii (JohnsL).

.„ ZOANTHARIA

4°

Synopsis of the Isozoanf/itis-species described here.

A. Single polyps or small colonies of two specimens with tnbe or groove-shaped ccenenchyme, which is
well-developed, but probably unattached. The mesoglcea of the body-wall contains few cells excep-
tionally cell-islets. Number of mesenteries 28—32 6/i/bos?ts.

B. Single polyps or small colonies of densely placed polyps connected by an inconsiderable ccenenchyme.
The polyps are elongated, slightly attached.

a. Mesoglcea of body-wall contains few small cells. Number of mesenteries 32 — 36. Specific

nematocysts in the filaments 31—38// x 11— 12// arborescens.

aa. Mesoglcea of body-wall contains numerous, granular, fairly large cells. Mumber of mesenteries
34 — 38. Specific nematocysts in the filaments 36 — 53 // x 12/* davisi.

C. Colonies with large, fairly well-developed ccenenchyme.

b. Elongated, small polyps.

c. Number of mesenteries about 34. Specific nematocysts in the filaments partly large
26 — 34^ x 10 — 12/i partly smaller 14// x 5//. Well developed ccenenchyme tube-shaped
covering needles of Hexactinellidae (always?) islatidiais.

cc. Number of mesenteries about 30 Specific nematocysts in the filaments partly large
IO,_26/z x 10— i2ti, partly smaller 12—14// x 5—6//. Ccenenchyme band-like (on Cidaris

spines, always?) dubius.

bb. Polyp of moderate length or short.

d. Number of mesenteries 18 — 22. Specific nematocysts in the filaments 22—26 // x 7 p.
Mesoglcea of the body-wall almost homogeneous with very scarce cells. Ceeneuehyme
band-like, branched danicus.

dd. Number of mesenteries about 32. Specific nematocysts in the filaments partly large
31—43^ x 12//, partly smaller 15// x 7//. Mesogkca of the body-wall contains numerous
small cell-islets and less numerous large cell-islets often fused together to form lacunae.

Ccenenchyme band-like, branched magninsulosus.

ddd. Number of mesenteries 38—40. Specific nematocysts in the filaments partly large
41—48// x 14—17//, partly smaller 17 — 19// x 7//. Mesoglcea of body-wall contains
numerous small cell-islets and scattered large ones. Lacunae-system slightly developed,

ccenenchyme of small dimensions multinsulosus.

dddd. Number of mesenteries 38-40. Specific nematocysts in the filaments partly large
3I_40/i x 12 — 14(19)//, partly smaller 17 — 19^ x 7//. Mesoglcea of body-wall contains
numerous, often elongated cells and larger or smaller cell-islets sometimes fused together
at the base of the mesenteries. Large, thin ccenenchyme ingolfi.

Isozoanthus bulbosus 11. sp.

PI. 1, figs, 5, 6. PI. 2, figs. 14 — 16. PI. 6, fig. 1.
Occurrence: 65°34/N., 7°3i'W. 762 Danish fathoms. Bott. temp. — o-8°. St. 105 Ingolf Ex.
Several specimens.

ZOANTHARIA

41

66°23'N., 7°25'W. 957 Dan. fms. Bott. temp. — ri°. St. 104 Ingolf Exp. several spec.

125
117

116

— 2 spec.
- — 12 spec.

— several spec.

— several spec.

32 Spitzbergen Ex. 18984,9 2spec.R.M.
41 Romer & Schaudinii. Berlin M.
32 Ingolf Exp. several spec.

68co8'N., i6°02'W. 729 — — — — — o-8°.

b9°i3'N., 8° 23' W. 1003 — — — — — ro°.

69°3i;N., 7°o6'W. 1309 — — — _ _ 1°.

70°05'N., 8°26'W. 371 — — — — —0-4°.

730 3'N., i8°3o'W. 410 m. 20.

8i° 20' N., 2o°30' E. 1000 m.

66°35'N., 56°38'W. 318 Dan. fms. — - 3-9".

Dimensions in the preserved state. The largest breadth of the polyps was about 0-55 cm.
The height was about 07 cm. excluding the groove-shaped ecenenchyme which may be of variable length
(greatest length observed 14 cm.).

The colour of living specimens has not been observed. In the preserved state the polyps are
dirty coloured, lighter or darker. The polyps which are strongly incrusted witli foraminifera look as
if they were covered with white grit.

External appearance. The polyps are pear-shaped, in the proximal part often drawn out
into a long narrow stalk, which often again increases a little in diameter towards the point and is
sometimes somewhat swollen (see fig. 6 PI. 1 showing the most typical appearance of the polyps). This
stalk which often had a groove-shaped appearance (fig. 15 — 16 PI. 2) does not however belong to the polyp
itself but to the ecenenchyme. The cavity of the polyp namely is continued in the stalk part only as
large canals, in contrast to what is found in I. arborescens. As the polyp, also in contrast to I. arborescens,
is always unattached, this part which is strongly incrusted probably serves as a sort of anchor for
the polyp. The groove-shaped part may possibly have surrounded some object, though the large material
collected affords no evidence of this. The polyps are nearly always single, and only very seldom
(observed in a few cases only, fig. 5, 6, PL i) does the stalk-shaped part send out another polyp. The
body-wall is richly incrusted, probably mostly with foraminifera densely placed, further, with a smaller
number of sand-grains and sponge-needles, the latter found mostly in the upper part. In the specimens
from St. 116 the sand-grains predominate and these polyps are darker; in specimens from St. 32 the
incrustation consisted exclusively of lighter or darker sand-grains interspersed with a few sponge-needles.
In the specimens collected at St. 105 as also in those dredged by Romer & Schaudinii, the capitular
region was well-marked, owing to the main incrustation being made up of sponge-needles, while the
lower part was richly beset with foraminifera. In another specimen I was able to remove large pieces
of a sponge, and it is possible that this is symbiotic with the polyp. In two specimens collected during
the Spitzbergen Expedition of 1898 the incrustation consisted mainly of sand-grains and sponge-needles,
while the foraminifera were scarce. The capitular furrows were indistinct and generally not to be seen
in the contracted, preserved polyps. In a half expanded specimen (fig. 5 PI. 1) on the other hand faint
capitular furrows could be observed. In a specimen from St. 32 I counted 13 capitular furrows with
well-marked sand-grain ridges iii the distal part. The whole polyp is of a more vigorous appearance
than /. arborescens.

The oesophagus is very short, the siphonoglyphe broad, the hyposulcus almost of the same length
as the oesophagus.

Tlie Ingolf-Expcdition. V. 4. 6

.„ ZOANTHARIA

4*

Anatomical description. The ectoderm of the body-wall is large, continuous and richly
incrusted. It contains sparse, uniformly broad nematocysts with greatly twisted thread (length 31—36//,
breadth I2«). The mesoglcea is fairly thick, mostly incrusted and contains a few large cell-islets and
now and then cell-groups, surrounded by inconsiderable protoplasm (PI. 6, fig. 1). The entoderm is thin.
In the capitular region the ecto- and entoderm become thicker, especially the former, while the meso-
glcea gets thinner.

The sphincter is straight with few folds, the musculature strong.

The longitudinal musculature of the tentacles is strong. The spirocysts of the ectoderm very
numerous, whereas the thick-walled nematocysts are scarce, about 22^ long sometimes smaller.

The oesophagus is almost without longitudinal folds, probably because it is very much expanded.
The ectoderm contains numerous thick-walled capsules (length 17— 24^x6 «) and is several times
thicker than the mesoglcea. In the distinct siphonoglyphe the mesoglcea is considerably thickened,
especially where the directive mesenteries are attached. The ectoderm of the siphonoglyphe is thinner
than in the oesophagus.

The number of mesenteries is 28—32, i. e. less than in /. arborescens though the latter has a
much smaller diameter than /. bulbosus. 9 specimens examined had 28 mesenteries, 1 had 32 and 3
had 30, 9 macro and 7 micro on the one side and 8 macro and 6 micro on the other. In one case at
least the right side was the most developed. The mesenteries are thin, somewhat thickened inwards
and extending below the oesophagus a long way into the gastrovascular cavity, the micro-mesenteries
are thin but become broader below the oesophagus. The lamella of the longitudinal muscle is fairly
well-developed especially just below the oesophagus, where it is provided with some closely-lying folds.
The parieto-basilar muscles are weak. The longitudinal and parieto-basilar muscles extend some
distance out onto the body-wall.

The structure of the filaments is typical. The glandular tract contains sparse thick-walled
nematocysts broader at the one end and with distinct basal part to the spiral thread (length 19 — 22 (24)//,
breadth 6^), further there are also granular thick-walled capsules (length 26— 31^, breadth 5//, some-
times smaller). In a specimen from St. 32 I found some very few small egg-shaped capsules (length
10— ii», breadth 4/;). These may possibly also be present in other specimens but owing to their
small size and scarce occurrence may easily have escaped notice. The large nematocysts with greatly
twisted thread are very seldom observed (length about 36//, breadth 12 ;i) and are generally absent
altogether. I have examined these nematocysts of the filaments in various specimens from different
localities and found them in the main to be in agreement with each other. It seems characteristic,
that the nematocysts with greatly twisted thread are extremely scarce if present at all. Nor do smaller
nematocysts of the same kind as the preceding seem to occur, in contrast to what we find in many
other Isozoanthus-species, or if occurring are extremely scarce. In their place thick-walled nematocysts
of a somewhat granular appearance may be observed.

The polyps are dioecious.

ZOANTHARIA

43

Isozoanthus arborescens (Dan) Carlgr.

PI. i figs. 1 — 2, PI. 2 fig. 27, PI. 3. fig. 5, PI. 6, fig. 2.

Epizoanthus arborescens n. sp. Dauielssen Norw. North Atl. Ex. Actinida. 1890. Tab. 6 fig. 6 Tab. 24

figs. 1—4.
Isozoanthus arborescens (Dan) Carlgren in Nordgaard 1905 Investig. in Norwegian fjords p. 159.

Occurrence: 6o°37' N., 27°52'W., 799 Dan. fins. Bott. temp. 4-5°. Ingolf Ex. 1 spec.

65°28'N., 27°39'W. 450 Dan. fms. Bott. temp. 5-5°. Ingolf Ex. St. 97 5 spec.

67°52' N., i3°58/ E. 247 m. clay Bott. temp. 4-9°. Norw. North Atl. Ex. 23/6 1877. St. :49-
Bergen M. R. M.

S. E. of Mortsund 200 m. Bott. temp. 6-6°. 22/2 1899 Nordgaard. 1 colony.

12 miles E. by S. of Reine 150 m. 3/3 1899 Nordgaard. 2 spec.

68° 15' 5" N., i5°49'E. Tranodybet 607—640111. Bott. temp. 6-3°. 16/3 1899 Nordgaard.

Dimensions in the expanded state, probably measured on living specimens: "up to 3-5 cm.
in length with a basal part only 05 — o-6 cm., the uppermost extremity i-2 cm. in breadth." Dauielssen.
The largest specimen from the Ingolf Expedition had in preserved state a length of 2'8 cm. , a
breadth at the base of 0-2 cm. and at the apex of 035 cm.

Colour according to Dauielssen. "The incrusted portion of the body is grey with a play
of a slightly greenish colour. The oral disc is almost white with a reddish tinge. The tentacles pale
rosy-red."

External appearance. Dauielssen has given a good description thereof. The polyps are
solitary and connected with each other by a very small ccenenchyme attached to stones (or Serpula-
tubes or similar objects, see Danielssen fig. 6, Tab. 6, fig. 1, Tab. 24). The colonies are often attached
by means of a thin membranous part, from which an inconsiderable tube-shaped ccenenchyme extends
sending out numbers of polyps which make the colon}' look like a plant branching off at the base.
Though not a little incrusted the polyps are rather slender and very elongated with a narrow, long
basal part, which gradually becomes broader towards the distal part. In the contracted polyps the
broadest part lies a little way from the distal end. The polyps from Mortsund (fig. 1 PI. 1) were
strongly contracted and consequently very firm, and the basal part of the polyps did not project so
much as in the other, more developed polyps from other localities. Dauielssen states that they have
16 capitular furrows. On the preserved specimens these are however very indistinct and only in the
Mortsund specimens have I been able to trace them. The body-wall is incrusted with sand-grains,
though not in very great quantities, so that "when the animal is extended and in full vigour, they
permit the white-red integument to shine through it." (Dauielssen).

The number of tentacles agrees in all probability with the number of mesenteries, in which
case it is 32—36. The innermost row of tentacles are according to Danielssen very long. The same
author also states that the oral disc is "rather flat and finely folded, the oral aperture is almost circular."

The oesophagus is short with well-marked siphonoglyphe and distinct hyposulcus.

Anatomical description. Danielssen has described the anatomy of this species but as
usual very unsatisfactorily, especially with regard to the musculature, which according to his work

, . ZOANTHARIA

44

does not differ from that of the other Zoanthidae. He has even made a mistake with regard to the
arrangement of the mesenteries, as can be seen from his fignre showing the grouping of the mesenteries
where he has not observed the couple of mesenteries forming the macro-type. This is for example
seen from the fact, that fig. 4 Tab. 24 shows 18 macro-mesenteries, whereas fig. 3 only has 16, which
according to the later number of macro-mesenteries is in agreement with the description. As I think
it superfluous to point out Danielssen's mistakes in detail, I shall in the following pay no attention
to his anatomical description of this species, but only describe the structure as I found it in a type-
specimen from Bergens Museum, supplemented by examination of the material collected by Nordgaard
and during the Ingolf Expedition.

The body-wall is more or less incrusted with sand-particles, here and there sponge-needles
occur and sometimes also foraminifera. The incrustation reaches a longer or shorter distance into the
mesogloea, which however is not so much filled with the incrustation that its structure cannot be seen.
The ectoderm is continuous with a generally thin but sometimes thicker cuticle on which are fixed
particles of detritus Though comparatively broad the ectoderm is considerably thinner than the
mesoglcea and is, as usual, most developed in the capitular region. In the greater part of the body-
wall there is a fairly frequent occurrence of nematocysts with greatly twisted thread (length 31 — 41 /i,
breadth 12 fi). The mesoglcea is thick and contains small cells of more or less frequent occurrence
PI. 6 fig. 2). Ectodermal canals are also found though very seldom. On certain sections of one of the
type-specimens I observed some elongated cells, the long outshoots of which were parallel to the
margin of the mesoglcea. They lay either very far into the mesoglcea or near its inner margin. If
the position of these cells were not variable, they might possibly be considered as the remnants of a
ring-sinus, which however can hardly be the case, as these elongated cells are not of constant occur-
rence. An encircling sinus is absent. The entoderm is not large and several times thinner than the ectoderm.

The sphincter is entodermal and in transverse sections deep semicircular folds may be seen
(fig. 5, PI. 3). Where the sphincter breaks though the mesenteries one may, as in all Parazoanthus-
species, obtain sections which if viewed externally give the impression that the sphincter is mesoglceal,
but this is not the case.

The structure of the tentacles and the oral disc is in agreement with other Zoanthidae. The
ectoderm of the tentacles contains numerous spirocysts and many 14— 17 /* long, typical thick- walled
capsules. The longitudinal musculature of the tentacles is fairly strong. The mesogloea of the tentacles
is also incrusted.

According to the more or less contracted state, the oesophagus is rounded, oval-shaped or more
flattened. The siphonoglyphe is fairly distinct, but the mesoglcea is only somewhat thicker than in the
other parts of the oesophagus. The ectoderm of the oesophagus is considerably larger than the thin
mesogloea. The difference in height between the ectoderm of the oesophagus and the siphonoglyphe
is on the other hand quite inconsiderable. Owing to the small development of the oesophagus I have
not been able to make glycerine-preparations.

Mesenteries. Of 4 specimens examined 2 had 32, 1 had 36 typically arranged mesenteries. The
4th specimen with 34 mesenteries had 9 macro and 7 micro-mesenteries on the one side, while on the
other side there were 18 mesenteries irregularly arranged. This side namely was partly arranged

ZOANTHARIA

45

according to the micro-type, and the 12th mesentery from the endocoele of the micro-directive mesenteries
was a macro-mesentery instead of a micro-mesentery.

In the sexual region the macro-mesenteries are short and reach only a little way into the
gastrovascular cavity. Their mesoglcea is fairly well-developed. The longitudinal musculature forms
few but fairly deep folds. The parieto-basilar muscles are weak and unfolded. The micro-mesenteries
are moderately developed with muscles as on the macro-mesenteries.

The filaments have the typical structure. The glandular tract contains many uniformly broad
nematocysts with greatly twisted thread (length 32 — 38//, breadth n — 12 ft). In the type-specimen I
found also some very small oval nematocysts (length 17^, breadth 7 p). Further, the glandular tract
contains fairly many thick-walled nematocysts with distinct basal part to the spiral thread, which are
broader at the one end (length 17—22/*).

The animals are dioecious. The macro-mesenteries bear as usual the sexual organs. On the
1st couple of macro-mesenteries reckoned from the directive micro-mesenteries these are weaker than
on the other proto-mesenteries, and the same applies to the youngest meta-macro-mesenteries.

Isozoanthus davisi n. sp.

PI. 2, fig. 17. PI, 7, fig. 1.

Occurrence: Davis Straits 66° 35' N., 56°38/W. 318 Dan. fins. Bott. temp. 3-9°. Ingolf Expedition
St. 32 several specimens (together with /. bulbosus and Epizoaiitiuts lindahli).

Dimensions: The length of the polyps reached up to 1-40111., largest breadth about 0-4 cm.
in the contracted state.

Colour in alcohol: light or dark sand-coloured.

External appearance. The majority of the specimens formed small colonies consisting of
a few polyps connected with each other by a small, generally thin ccvnenchyme and attached to
small yellowish, sometimes branching sand-tubes (of Rhizammina?). All the polyps were probably
attached to such objects, though in one case it looks as if the colony was free, probably arising from
the fact that a piece of the ccenenchyme is worn off. The polyp is narrowest at the base, from which
part it becomes more or less wide upwards, according to the more or less state of contraction. The
capitular furrows are very indistinct. The whole body-wall and ccenenchyme of the polyps is richly
incrusted with sand-grains, here and there also sponge-needles occur, especially in the uppermost part.

The tentacles are short.

The oesophagus is short, the siphonoglyphe distinct with well-marked hyposulcus of almost the
same length as the oesophagus.

Anatomical description. The ectoderm of the body- wall does not seem to be very high
except in the capitular region. It is mostly absent and if present filled with detritus and incrusted.
Nematocysts with greatly twisted thread 38 — 48^ long and 11 — 12^ broad are fairly common in the
proximal part, but very scarce distallv. Further, the ectoderm of the body-wall contains egg-
shaped nematocysts resembling those in the filaments (length 22 — 26 p, breadth 5 — 7^). The mesogloea
is thick, several times thicker than the ectoderm and contains numerous, scattered large cells, generally

46

ZOANTHARIA

oval-shaped and with granular contents of close-lying grains (PI. 7. fig. 1). The whole mesoglcea with
exception of the very innermost part is incrusted. The entoderm is moderately developed, sometimes
darkly pigmented.

The sphincter is long and strong, in the distal part it forms a few deep folds, in the proximal
numerous but small folds.

The ectoderm of the tentacles contains numerous spirocysts, whereas the thick-walled capsules
(length about 22//), are very scarce. The mesoglcea is richly incrusted.

The ectoderm of the oesophagus is very high and contains numerous nematocysts 24— 26/i long
and thick-walled; further, there is a sparse occurrence of larger or smaller nematocysts with coiled
thread as in the filaments. The mesoglcea is thin though however thickened in the siphouoglyphe.

The number of mesenteries varied in the two specimens examined
between 34 and 38. In both specimens the one side had one mesentery
more than the other.

The macro-mesenteries are rather thick even in specimens with ex-
panded mesenteries, whereas the micro-mesenteries are weak and in the
lower part of the oesophageal region extend a little over the main part
of the entoderm of the body-wall. In specimens having the mesenteries
contracted broadwise the longitudinal musculature lies in deep folds even
extending below the oesophagus (Text-fig. 6). The parieto-basilar muscles
are very weak. The distribution of the longitudinal musculature on the
body-wall is fairly considerable, whereas hardly any parieto-basilar muscles
occur. Below the oesophagus extend the mesenteries, which contain the
undeveloped sexual organs reaching some way into the gastrovascular
cavity.

The filaments have the usual structure. Two kinds of nematocysts

with greatly twisted thread and often of a somewhat curved shape occur,

the one kind larger 37 — 53// long and 10—12// broad, the other smaller

elongated, egg-shaped, somewhat broader at the one end (length 15 — 22 a, largest breadth 6—7//).

Further, the filaments contain thick-walled nematocysts broader at the one end than at the other

(length 22— 24/i, breadth 5—6//).

One of the specimens investigated had undeveloped testes.

Text -fig. 6. Transverse sectioii
through a portion of the body-
v, all with mesenteries and oeso-
phagus of hozoanthus davisi. Meso-
glcea and muscles black, ectoderm
of the oesophagus shaded, ento-
derm dotted. The light parts in
and outside the mesoglcea of the
body-wall represent incrustations.
Ectoderm of the bodv-wall absent.

Isozoanthus islandicus.

PI. 2. fig. 20. PI. 7 fig. 2.

Occurrence: 64°45'N., 29°o6'W. 568 Dan. fms. Bott. temp. 4-4°. Ingolf Exp. St. 90. 1 colony.

Dimensions: Length of the largest polyp 0-9 cm., greatest breadth about 02 cm.

Colour in alcohol: dark.

External appearance. The only colony of this species was attached to a couple of spicules
of a Hexactinellida. The thin cceuenchyme was very large encircling the spicules almost entirely, so
that it formed a tube round these. In fig. 20 PI. 2 we see very little of the spicules. The polyps,

ZOANTHARIA 47

which iii the full-grown specimens especially are very elongated in shape, lie very far from each other.
They are narrowest at the base but expand somewhat towards the distal part. The capitular furrows
are very indistinct. The upper margin of the polyps is somewhat rounded. The polyps as well as
the ccenenchyme are richly though not very conspicuously incrusted.

The oesophagus is short, the siphonoglyphe distinct. Hyposulcus?

Anatomical description. The ectoderm of the body-wall is high and reaches almost the
same size as the mesoglcea. Except in the capitular region it contains fairly man}- nematocysts with
greatlv twisted thread, length 29—34,0, breadth 10 — 12 //. Particles of detritus are found in and on
the ectoderm. The mesoglcea is moderately developed , and very much incrusted with foraminifera
(dissolved in the section on PL 7, fig. 2), sand and sponge-needles, the latter heaped up especially in
the capitular region. Scattered granular cells of moderate size, sometimes also larger, occur fairly
commonlv here (PI. 7, fig. 2). The entoderm is considerably thinner than the ectoderm.

The sphincter is long and strong, of the same appearance as in other Isozoanthus-species.

Regarding the tentacles I am unable to give any other information than that their ectoderm
as usual contains numerous spirocysts.

In the oesophagus the ectoderm is high, the mesoglcea thin, whereas in the siphonoglyphe the
conditions are reversed.

In the single specimen sectioned, the number of mesenteries, as far as I was able to see on
the somewhat torn sections, was 34, 10 macro and 8 micro on the one side and 9 macro and 7 micro
on the other. The micro-mesenteries are moderately developed. The longitudinal musculature is but
moderately developed, forms few or no folds at all, the parieto-basilar muscles weak. So far as I was
able to see on the not well-fixed material the longitudinal and parieto-basilar muscles extended only
a moderate distance on the body-wall.

The filaments have the usual structure. The glandular tract region contains large nematocysts
with coiled thread (length 26—34^, breadth 10— 12 /i), but they only occur sparsely as is also the case
with some smaller, similar capsules (length 14 ft, breadth 5 //) and some thick-walled capsules broader
at the one end (length 22 fi). Inside the filaments in the entoderm of the mesenteries we also find
many nematocysts (length 14 — ij /j, breadth 10— 11 jj) and numerous elongated, generally curved nema-
tocysts (length 22—26^, breadth 5//). These capsules probably do not belong to the animal, but are
foreign nematocysts taken up by the ectoderm (2 specimens examined).

The animals were not sexually ripe.

Remarks. The above-mentioned species is undoubtedly closely related to Isozoanthus dubius
from St. 45, but differs from the latter mainly in the larger nematocysts, and the stronger sphincter.
Later examination of a larger material may possibly show that they can be thrown together to form
one species, but till then I think it best to separate them.

Isozoanthus dubius n. sp.

PI. 2, fig. 19. PI. 7, fig. 3.
Occurrence: 6i°32'N., 9°43'W. 643 Dan. fms. Bott. temp. 4-i7°. Ingolf Exp. St. 45 1 colony.
Dimensions: Length of the largest polyp o-8 cm., greatest breadth 0-3 cm.

48

ZOANTHARIA

Colour in alcohol: tawny sand-coloured.

External appearance. The only colony of this species was attached to a fragment of a
Cidaris spine. The colony had a thin, disc-like ccenenchyme from which two polyps emerged at a
long distance from each other. The polyps are elongated, narrow at the base and broader upwards.
The distal margin, which completely covered the tentacles, was truncate. The capitular furrows were
very indistinct. The incrustation of the polyps and the ccenenchyme consisted of sand-grains, fora-
minifera and sponge-needles. The oesophagus is short, the siphonoglyphe distinct. Hyposulcus?

Anatomical structure. The ectoderm of the body-wall is high, slightly incrusted with the
above mentioned foreign bodies and detritus particles. In the distal part the nematocysts are very
scarce, in the proximal part on the other hand nematocysts with coiled thread are common (length
22 — 29 fi, breadth 12//). The mesogloea is thicker than the ectoderm, richly incrusted and contains
scattered, fairly numerous, often oval-shaped, granular cells of moderate size (PI. 7, fig. 3). In the
section figured, the foraminifera have been dissolved by means of nitric acid, so that only the cavities
in which they were lying can be seen. The ectoderm is thin.

The sphincter is considerably shorter than in /. islandicus and has in the distal part some large
folds, which soon pass over into the ring-muscle layer of the body-wall.

The tentacles, of which I made no macerated preparation, contained in the ectoderm numerous
spirocysts. Whether also thick-walled nematocyst capsules occur, I am unable to tell from the material
sectioned.

The oesophagus is as in I. islandicus.

In the examined specimen the number of mesenteries was 30, 9 macro- and 7 micro-mesenteries
on the one side, 8 macro- and 6 micro-mesenteries on the other. In the lowest part of the oesophageal
region the micro-mesenteries are weak and only reach a little beyond the main lamella of the entoderm.
The macro-mesenteries are thin, the longitudinal and parieto-basilar muscles weak, but reach a long
way on the body-wall. The macro-mesenteries below the oesophagus seem to be longer than in
/. islandicus.

The glandular tract of the filaments contains a few, large nematocysts with coiled thread (length
19 — 26(29)// generally 24, breadth 10 — 12 generally 10 — n^) with rounded ends and fairly many, smaller,
similar capsules (length 12 — 14 /t, breadth 5 — 6 p). Further, there is a common occurrence of thick-
walled capsules, broader at the one end (length 14 — 17//).

The sexual organs were not developed in the specimen sectioned.

Remarks. See under I. is/a adieus.

Isozoanthus danicus u. sp.

PI. 1, fig. 3—4. pi. 7, fig. 4.

Zoanthus couchii Gosse, Mortensen. Smaa biol. o. Faun. Iagttagelser, Videnskab. Medd. 1897. p. 316.
Occurrence: Denmark, L,imfjord. Mortensen; R. Horriug Sept. 1902. Copenh. Museum R. M.
Dimensions. Height of the retracted polyps 0-25 — 0'4 cm., breadth about 0-2 cm.
Colour in alcohol. The ccenenchyme and the majority of the polyps dark or dirty-coloured,

ZOANTHARIA

49

capitular region light. In the living condition: ccenenchyme and the proximal part of the polyps
brown, disc brown frequently with white radial stripes (Mortensenl.

External appearance. The ccenenchyme consists of an irregularly branched network with
a thin attachment to dead oyster-shells. The polyps emerge from the ccenenchyme sometimes at smaller,
sometimes greater intervals. They are small, cylindrical and when much contracted almost as high as
broad or the breadth is a little larger (PI. i, fig. 4), in less contracted state (PI. i, fig. 3) they are twice
as high as broad. In the contracted state the distal part is rounded. The capitular furrows are indistinct
on the not very well preserved material, so that their number cannot be given.

The oesophagus is short, the siphonoglyphe distinct, but the hyposulcus seems to be short.

Anatomical description. The ectoderm of the body-wall is moderately developed and as
far as I am able to see continuous (owing to the strong contraction and the folding resulting there-
from it is difficult to determine this with certainty). It is incrusted with coarse sand-grains, some
sponge-needles and detritus, in which numerous diatoms occur. The ectoderm contains uniformly broad
nematocysts with greatly twisted thread (length 22—26^, breadth generally 7 sometimes 10//). Whether
they are numerous or not I am unable to say for certain. The mesoglcea is moderately developed,
the outer part incrusted, it has no lacunae and very few cells (cell-islets) which sometimes lie in groups
close to each other. The cells are however so scarce that the mesoglcea looks almost as if it was
homogeneous and cell-free, this being fairly characteristic of the species (PL 7, fig. 4). The entoderm
is of moderate thickness and contains fairly many zooxauthellae, which besides occur everywhere in
the entodermal layer of the polyp.

The sphincter is entodermal, somewhat folded at the upper part and fairly long in consideration
of the small size of the animal. The musculature is strong so that the capitular region is very much
retracted in the contracted state.

The structure of the oesophagus seems to be the same as in the other Zoanthidae. The ectoderm
is high, the mesoglcea thin. I have not been able to make any macerated preparations of the oesophagus,
because this is so short and folded and badly preserved. The siphonoglyphe has a somewhat lower
ectoderm than the oesophagus, and the mesoglcea is a little thicker than in the oesophagus.

In 7 specimens examined the number of mesenteries were 18, 20, 20, 20, 22, 24, 24; the spec-
imens with 18 and 22 mesenteries had 1 couple of mesenteries more on the one side of the body than
on the other. It is difficult to see the arrangement, as the specimens especially in the oesophageal
region were badly preserved. It is worth noticing especially, that the sixth conple of proto-mesenteries,
i. e. the proto-mesenteries lying nearest to the meta-mesenteries, as also the macro-meta-mesenteries,
have not yet grown out to the oesophagus and had no filament (at least not in the specimen with 18
mesenteries). The sixth couple of proto-mesenteries, the micro-proto-mesenteries and all meta-mesenteries
seem to be almost equally developed. Though it might be supposed, that the polyps were brachyenemic,
it is however probable, that they are macrocnemic, though the 6th couple of proto-mesenteries have
not yet reached the oesophagus. This is also indicated by the small development of the macro-meta-
mesenteries. The micro-mesenteries at any rate are well-developed. The longitudinal musculature is
strong on the complete mesenteries, especially on the directive mesenteries, where it forms deep folds.

The Ingolf-Expedition. V. 4. 7

c0 ZOANTHARIA

The parieto-basilar muscles are weak, and as far as I have been able to see the longitudinal and
parieto-basilar musculature does not extend onto the body-wall or only very little.

The filaments have the usual structure. The glandular tract contains fairly many, often curved,
uniformly broad nematocysts with greatly twisted thread (length 22— 26/i, breadth about 7 p). Further,
it contains numerous thick-walled capsules about 17 /x long.

The species is dioecious. In most of the polyps ovaries or testes were found though at a fairly
early stage.

Isozoanthus magninsulosus n. sp.

PI. 1, fig. 7- PL 6, figs. 4-5.

Occurrence: 640 24' N., 280 50' W. 788 m. Bott. temp. 3-5°. Ingolf Ex. St. 10. 1 colony.

Dimensions in the contracted state. Length of the largest polyp o-6em., breadth 03 cm.

Colour in alcohol: dirty yellowish-brown. It may possibly have absorbed this colour from a
brown piece of paper covering the stone on which the colony was fixed, and which coloured the alcohol.

External appearance. The only colony of this species in the collection consisted of 8 larger
and smaller polyps placed fairly close to each other and separated by a large flat and very thin, band-
like ccenenchyme (PI. 1 fig. 7), attached to a stone. The polyps are cylindrical not elongated, with
distinct capitular forrows. All the polyps were retracted so that no tentacles were visible, the upper
margin was rounded. The polyps as well as the ccenenchyme were iucrusted with numerous foramini-
fera, giving the colony a granulated appearance. The oesophagus is very short, the siphonoglyphe
distinct with well-marked hyposulcus.

Anatomical description. The ectoderm of the body-wall is fairly high, continuous and in
the lower part of the polyp provided with fairly numerous and uniformly broad nematocysts about
34/i long and 13^ broad with greatly twisted thread. In the capitular region they seem to be wanting
but are replaced by small egg-shaped capsules like those in the filaments (length 12 — 14/<, breadth 6/1).
The mesoglcea is more than twice as thick as the ectoderm and like this incrusted with numerous
foraminifera and some few sponge-needles. The incrustation is mostly present in the outer half of
the mesoglcea but may often reach further into this. The part of the mesoglcea which is not incrusted
contains numerous cell-islets of larger or smaller size (PI. 6, fig. 5). The smaller as well as the larger
of these are often in connection with each other, thus forming a lacunae-system which is mostly
observed in the lower part of the body (PI. 6, fig. 4). A section through the mesoglcea of the body-wall
has therefore quite a different appearance from I. multinsidosns , where such lacunae-systems are only
seldom found. In sections of I. multinsulosus the cell-islets are consequently as a rule round or oval
whereas in I. magninsulosus they have a more irregular appearance owing to their connection with
each other. The large islets (the lacunae) are also considerably larger in I. magninsulosus than in
I. multinsulosus. In spite of the presence of a fairly well-developed lacunae-system one cannot speak
here of any defined encircling sinus. The entoderm is thin and slightly pigmented.

The sphincter has the same structure as the other Isozoanthus species described.

The ectoderm of the tentacles contains numerous spirocysts and fairly many thick-walled nema-
tocysts (length 17 — 19/i). The mesoglcea of the tentacles is often incrustated.

ZOANTHARIA

51

The ectoderm of the oesophagus has the usual structure. Nematocysts probably also occur
there, but as parts of the filaments are connected with the ectoderm of the oesophagus the macerated
preparation has given no certain information regarding the occurrence and appearance of the nema-
tocysts. The mesoglcea is thin and considerably weaker than in the siphonoglyphe.

Mesenteries. Of 3 specimens sectioned only one was so well fixed that I could determine the
number of mesenteries. This polyp has 32 typically arranged mesenteries. The mesenteries are thin,
the longitudinal as well as the parieto-basilar musculature weak. These muscles extend a long way
onto the body-wall. The micro-mesenteries are fairly well-developed even below the oesophagus.

The filaments have the usual structure. The nematocysts are partly large, uniformly broad capsules
with greatly twisted thread (length 31— 43 /i, breadth 12/1), partly smaller often somewhat curved (length
about 15U, breadth 7^). The latter are common. Further, the filaments contain fairly many, thick-
walled capsules with distinct basal part to the spiral thread and somewhat broader at the one end
(length 22 — 24//, breadth 7 n). The species is dioecious. The best preserved specimen had well-developed
testes 011 the macro-mesenteries.

Systematic remarks. In some respects this species resembles /. multinsulosus , from which
it differs however in a number of features. In /. magninsulosus the large cell-islets (the lacunae) in
the mesoglcea of the body-wall are, for example, more numerous and larger than in /. multinsulosus
(cf. above), in this species the incrustation consists of foraminifera, in /. magninsulosus of sand-grains,
and in this the ectoderm is less pigmented than there. In I. magninsulosus the number of mesenteries
is 32, in /. multinsulosus 38 — 40. Also the large nematocysts are somewhat shorter and especially
narrower here than in /. multinsulosus, though otherwise they resemble each other with regard to the
nematocysts.

Isozoanthus multinsulosus u. sp.

PI. 1, fig. 18. PI. 6, fig. 3.

Occurrence: 64°i5'N., i4°22'W. 68 m. Bott. temp. 7"07°. Ingolf Ex. St. 51. 1 colony.
65°43'N., i4°34'W. 90 m Bott. temp. 70. Ingolf Ex. St. 6. 1 colony.

Dimensions. The polyps were strongly contracted. Largest polyp about 0-45 cm. broad and
1 cm. high.

Colour. The polyps are black owing to the incrustation of black sand-grains. It is probable,
however, that the polyps are dark in themselves as the ectoderm and especially the entoderm are
darkly pigmented.

External appearance. One of the colonies consisting of 4 polyps was attached to a stone,
the other colony with 3 polyps to a Dentalium-tube. The greatly contracted polyps were connected
with each other by a very thin, spread ccenenchyme from which the polyps emerge, sometimes at
smaller, sometimes larger intervals. The polyps are short, the upper margin of the polyps retracted
in the distal end, not truncate but rounded. Capitular furrows present but so indistinct that I am
unable to state their number. The tentacles have the usual structure. The oesophagus is short,
siphonoglyphe deep, hyposulcus distinct.

r

c2 ZOANTHARIA

Anatomical description. The ectoderm of the body-wall is continuous, fairly high and
contains fairly many, uniformly broad nematocysts with greatly twisted thread — length (38)41 — 48/z,
breadth 14 — 17 p- The ectoderm and outer part of the mesoglcea are strongly incrusted, almost ex-
clusively with black sand-grains interspersed with a few sponge-needles. The mesoglcea is thick, the
inner half and probably also the outer one (owing to the strong incrustation it has been rather difficult
to study the structure of the mesoglcea) contains cells and numerous cell-islets (PI. 6, fig. 3), the majority
of which are small but others reach quite a considerable size though not so large as in I. magninsulosus.
More seldom the cell-islets fuse together to form elongated lacunae but not so great as in /. magnin-
sulosus. An encircling sinus however is not found. The entoderm is thin, with black pigmentation.

The sphincter is entodermal, long and in the upper end has some fairly deep, often large folds.

The ectoderm of the tentacles is high and contains numerous spirocysts, besides many thick-
walled nematocysts (length 19 — 24 /z) and a few large capsules with greatly twisted thread of the same
kind as in the body-wall, but somewhat small (34 /i long).

The ectoderm of the oesophagus is fairly high and contains numerous thick-walled capsules
(length 22 — 24 /i), and the same kind of large nematocysts as found in the body-wall though somewhat
smaller (38 — 41 ji long). The mesogloea is thin and considerably weaker than in the siphonoglyphe,
whose ectoderm as usual is lower than that of the oesophagus.

In the two specimens examined the number of mesenteries was 38 and 40. The second polyp
was typical, the first had 1 couple of mesenteries more on the one side than on the other. The micro-
mesenteries are moderately developed even below the oesophagus and several times broader than the
entoderm of the body-wall. The mesogloea of the mesenteries is thin, the longitudinal musculature
weak and partly folded, the parieto-basilar muscles weak. The extension of the longitudinal and
parieto-basilar muscles on the body-wall is distinct though not considerable. Below the oesophagus
the mesenteries are narrow, so that the gastrovascular cavity is large.

The filaments have the usual structure. In the glandular tract there is a rich occurrence of
large capsules of the same kind as in the body-wall (length 41 — 48^, breadth 14 — 17 p) and a sparse
occurrence of similar smaller capsules (length 17 — 19 «, breadth 7^); further, it contains fairly many
thick-walled capsules with distinct basal part to the spiral thread and somewhat broader at the one
end (length 22—24//, largest breadth 6pi).

The sexual organs were not developed in the specimens examined.

Isozoanthus ingolfi n. sp.

PI. 2, fig. 25. PI. 6, fig. 6.

Occurrence. 64°54'N., 55°io'W. 393 fms. Bott. temp. 3-8°. Ingolf Ex. St. 27 several spec-
imens (type).

Finmarken Ogsfjord Loven, 1 colony with 2 polyps.

Dimensions. Largest polyp (from Davis Straits) 1 cm. long and 0-550111. broad.

Colour in alcohol: light sand-coloured, the specimen from Finmarken containing small, scattered
black sand-grains.

ZOANTHARIA 53

External appearance. Small colonies consisting of some polyps connected by a thin, fairly
extensive ccenenchyme attached to small stones, mollusc-shells or worm-tubes. The polyps are cylindrical
and sometimes, owing to contraction, a little thicker in the distal part, and longer than broad. In the
retracted state the distal part is almost truncate with a depression in the middle. Capitular furrows
present but very indistinct, in the best preserved specimen 20 were observed. The polyps as well as
the ccenenchyme were incrusted with sand, now and then with sponge-needles; near the ectoderm
mud-particles are fixed. The incrustation is not very strong and restricted to the ectoderm and
especially the outer part of the mesoglcea.

The oesophagus is short with a very distinct deep siphonoglyphe and well-developed hyposulcus,
which is somewhat longer than the oesophagus.

Anatomical description. The ectoderm of the body-wall is moderately developed, yet several
times thinner than the mesoglcea. In the proximal part of the body-wall large nematocysts with coiled
thread are found, sometimes sparsely (specimens from the Ingolf Expedition), sometimes more commonly
(length 31— 36/*, breadth 12 — 14//)- In the Fiumarken specimen some smaller capsules of the same
appearance as the smaller egg-shaped capsules of the filaments are also found. The mesoglcea is thick
and contains numerous cells with long outshoots, sometimes running in the direction from ecto- to
entoderm (PI. 6, fig. 6) and sometimes even more irregularly arranged. Further, there is a sparse
occurrence of small cell-islets and large cells. The latter sometimes fuse together to form (ectodermal ?)
lacunae. The large cell-islets lie often near the insertions of the mesenteries. As the cell-islets fuse
together forming lacunae, it may sometimes on certain parts of the proximal part of the polyps look
as if traces of an encircling sinus might be present. As the cell-islets lie fairly irregularly and are
generally separated from each other by large portions of mesoglcea, especially in the distal end of the
polyp, the lacunae cannot however be considered as an encircling sinus. The entoderm is thinner
than the ectoderm.

The sphincter resembles that of /. arborescois and forms large folds.

The ectoderm of the tentacles has the usual structure and contains numerous spirocysts and
fairly thick-walled nematocysts (length 19—20//). Besides there are very sparsely large capsules of
the same kind as in the ectoderm of the body-wall. In the specimen from Fiumarken I observed
small capsules with coiled thread (length 19 p, breadth 7 ;t). The mesoglcea of the tentacles is incrusted
though only inconsiderably.

The ectoderm of the oesophagus is high and contains fairly many thick-walled nematocysts
(length 17—22//). Further, there also occur, though only very sparsely, some larger or smaller capsules
with coiled thread of the same appearance as in the filaments. The ectoderm of the siphonoglyphe is
as usual considerably lower than in the oesophagus, whereas with regard to the mesoglcea the
condition here is reversed.

In the two specimens taking during the Ingolf Expedition the number of mesenteries was 40
and 38; the first of them had the mesenteries arranged typically, whereas the second had a pair of
mesenteries less on the one side than on the other. Of the specimens from Finmarkeu one had 46
mesenteries, 13 macro and n micro on one side and 12 macro and 10 micro on the other. Another
specimen probably had 44 mesenteries — n being observed in one fourth part of the polyp.

ZOANTHARIA

The longitudinal musculature is fairly well-developed but forms large folds. The parieto-basilar
muscles are moderately developed but in transverse section no folds are seen. The parieto-basilar and
longitudinal musculature extend a long way onto the body-wall. The micro-mesenteries are not very
well-developed.

The filaments have the usual structure. The glandular tract contains larger and smaller nema-
tocvsts with greatly twisted thread, the larger are uniformly broad 31 — 43 ^ long and 12 — 14^, some-
times even 17 broad, and scarce to not seldom, the smaller are egg-shaped 17—19// long and 7// broad
and not seldom. Further, it contains thick-walled capsules with distinct basal part to the spiral thread
and broader at the one end than at the other (length 17—19// long, largest breadth 5//). Sometimes
also typical thick-walled capsules are present (length 24 //).

The sexual organs were not developed in the specimens examined by me.

Besides the above-mentioned Isozoanthus-species a specimen of an Isozoanthus type which I
could not refer with certainty to any of the above-described was dredged at St. 27 during the Iugolf
Expedition. The polyp has a length of 2 cm. and a breadth in the capitular region of 04 cm., at the
base it measured 0-3 cm. and was of a dark colour. The polyp was attached to a stone by an in-
considerable, irregularly triangle-shaped ccenenchyme on which a faint indication of another polyp was
visible. The large polyp gradually increased in breadth towards the capitular region which is some-
what rounded. The capitular furrows are indistinct. The oesophagus is short, the hyposulcus well-
developed. The body-wall at least in the upper part is greatly expanded and consequently thin. The
ectoderm is almost half as thick as the mesoglcea, continuous and incrusted with mud and detritus
particles, which partly at least give the animal its dark colour. The mesoglcea is quite filled with
sand-grains and a few sponge-needles. It also contains numerous cell-islets and cells, but owing to
the strong incrustations it is very difficult to get a true idea of the nature of the mesoglcea.

The sphincter resembles that of the other Isozoanthus-species. The oesophagus has the usual
structure. The ectoderm contains thick-walled capsules 19—22// long. There are 36 mesenteries which
are very much expanded so that the mesoglcea becomes very thin. The musculature seems to be
weak; the micro-mesenteries are well-developed. The filaments contain a few specific, uniformly broad
nematocysts (length 29—38, breadth 10 — 11 //) besides some more frequently occurring egg-shaped
capsules 13—15// and thick-walled capsules with distinct basal part to the spiral thread and somewhat
broader at the one end (length 19//). The sexual organs were undeveloped.

Owing to the small amount of material I have not named this form.

Genus Parazoanthus Hatldon and Shackleton.

Macrocnemic Zoanthidae with a diffuse entodermal sphincter muscle. The body
wall is incrusted, the ectoderm is continuous. Encircling sinus as well as ectodermal
canals, lacunae and c e 1 1 - i s 1 e t s in the m e s o g 1 o e a. Dioecious. Polyps connected b y
thin co en en chyme, (coenenchyme without cylindric horny skeleton).

ZOANTHARIA

55

I have given the diagnosis of Haddon and Shackleton, which seems to me good, and have
added the information, for the Genus Gerardia, that a true cylindric horny skeleton is wanting. I have
placed this however in brackets, as I consider further examination of the Gerardia skeleton desirable,
in order to ascertain how much of the skeleton actually belongs to the polyp, a determination that
can hardly be made without fresh or at least well-preserved material. Though I consider the cylindric,
connecting tissue of horn between the branches of the skeleton as being secreted by the polyps them-
selves, it is not quite excluded, that the other part of the skeleton belongs to another Authozoon, —
a condition undoubtedly existing as regards the basal part of the branched skeleton (cf. Lacaze-
Duthiers 1864). If it should be the case, that only the peripheral branches of the so-called Gerardia
skeleton have been secreted by the Zoanthid, the genus Gerardia approaches still more to the genus
Parazoanthus and comes so near' to this, that the question is, whether the two genera could not be
thrown together, especially as the inner structure of the Gerardia polyp agrees completely with that
of the Parazoanthus polyp even in such details as the presence of a well-developed encircling sinus.
In this case the only difference would lie in the skeleton, certain parts of which are tube-shaped in
Gerardia, while in Parazoanthus it is only present as a thin flat layer under the ccenenchyme, a
difference which is not essential but gradual and certainly is only dependent on the somewhat unequal
growth of the colonies. According to the rule of priority the genus name Gerardia would in such a
case have to be changed to Parazoanthus — an alteration which cannot be made, however, until the
question of the Gerardia skeleton has been definitely settled. Haddon has for the rest already in
1898 p. 408 expressed some doubt as to whether the skeleton in Gerardia was actually secreted by the
polyps themselves, though without making any further investigation into the matter himself.

The Parazoanthus species described here are two in number, one of which has already (1889)
been described in detail by Haddon and Shackleton, the other is new, named P. Haddoni. Further,
I give here some supplementary details regarding the anatomy of P. dixoni Hadd. & Shackl.

No species of Parazoanthus were dredged by the Ingolf Expedition.

Synopsis of the Parazoanthus species described here.

A. Capitular region in the contracted state not or very little swollen. Number of mesenteries
36 — 46 P. haddoni.

B. Capitular region in the contracted state swollen. Number of mesenteries 36 — 38.. P. anguicomus.

Parazoanthus haddoni n. sp.

PI. 1, figs. 9— 11. PI. 7, fig. 5.

Jutland Reef 100—200 fm. G. Pettersson 1881 R. M.

Jsederen 100 — 170 fm. Tob. Andersson & Westergreu 1877 R. M.

N. W. of Egersund 100 fm. N. Ols son & M. Udds trom R. M.

Haugesund and Bergen in S. E. 15 — 21 miles from land 100—170 fm. 01. Johansson R. M.

Stora Fiskebanken, Bergen in S. E. 100—180 fm. T. Andersson R. M.

56

ZOANTHARIA

N. W. of Bergen 30—200 fm. M. Olsson 1873, 1878; 90—200 fm. O. Mattson 1880; 100—150 fm.
M. Udd strom 1880 R. M.

N.N.W. of Bergen 90—200 fm. M. Uddstrom, G. Nilsson, M. Olsson 1880 R. M.

North Sea M. Uddstrom 1880 R. M.

North Sea north edge of the Fisher Bank 100—160 fm. B. Olsson R. M.

Size: The colonies form large aggregates sometimes of the size of a clenched fist and almost
always fixed on sponges (1 spec, on an Ascidian). In the contracted state the polyps of the largest
colonies (PI. I, fig. 16) reach a length of 19 cm. and a breadth at the base of 1 cm. In most of the
colonies the polyps are however considerably smaller.

Colour. In alcohol the colonr varies from dirty yellowish (PI. I fig. 10) to dirty grayish or
pure white (PI. I fig. 9 — 11). The dirty gray colour is generally predominant.

External appearance. The polyps form colonies often of large dimensions, which are attached
to large sponges. The ccenenchyme is fairly thin and extensive and sometimes forms narrow out-
shoots, on the end of which new polyps are formed (PI. I, fig. 9). A single colony, which by the way
was not quite typical, was found on an Ascidian. The polyps generally sit quite close to each other,
but sometimes the intervals between may be larger, especially when the ccenenchyme forms string-like
outshoots. Even when the tentacles are completely covered by the body-wall, the polyps are generally
considerably higher than broad. The breadth is however very considerable, greatest at the base and
tapering upwards; sometimes the distal part maybe somewhat swollen, especially in greatly contracted
polyps, though never so much as in P. dixoni and anguicomus. Otherwise, the polyps vary much in
size, as can be seen from figs. 9— n on PI. I, but there is no doubt that we are only dealing with
one and the same species. The body-wall is more or less wrinkled especially in the larger specimens.
The capitular furrows are generally distinct and reach up to 18—21 in number. The oesophagus is
of moderate length. The siphonoglyphe is distinctly marked, the hyposulcus developed but rather
short and does not attain to half the length of the oesophagus.

The ccenenchyme as well as the polyps is incrusted with sand-grains and sponge needles, to
which are sometimes added a few foraminifera. The sand-grains are generally predominant, but in
some cases the sponge-needles occur in quantities. The incrustation is not so strong as in P. anguicomus
but is very variable. Sometimes polyps are also found which are very little incrusted.

Anatomical structure. The ectoderm of the body-wall is very high and continuous and
contains nematocysts with greatly twisted thread of two different kinds, either large 41— 46/i long
and 17—18^ broad or small 24 p long and 12 — 13 fx broad. The number of capsules is variable
but the smaller ones are always more numerous than the larger and the proportional occurrence of
both kinds of capsules seems to be always the same. When the polyps are not strongly expanded,
the mesoglcea is somewhat thicker than the ectoderm. It is provided with numerous cells, cell-islets
and lacunae and a well-developed encircling sinus. The cell-islets and lacunae are generally numerous
(PI. 7, fig. 5), sometimes however scarce. The lacunae are here and there in distinct connection with
the ectoderm and encircling sinus. As a rule the latter is interrupted at a few places by mesoglceal
parts and narrow. Sometimes, however, I have found fairly strong mesoglceal bridges together with
a broader encircling sinus at the bases of the mesenteries, while the connecting canals between

ZOANTHARIA 57

these broader canal parts are narrow. This variation in structure of the encircling sinus is however
probably due to different states of contraction in the polyps, which may be concluded from the fact, that
the more abnormal encircling sinuses had a thicker mesogloea and were more contracted, while the
polyps with a more typical encircling sinus were expanded. But the fact also, that both kinds of
encircling sinus may be found in the same colony, goes to show, that we are not dealing with a variety.
The encircling sinus contains the same kind of nematocysts as the ectoderm of the body-wall.

The sphincter is more developed than in P. anguicomus and dixoni. While the muscular furrows
in the distal part are large and semicircular, they lie on the other hand closer to each other in the
proximal part (PI. 3, fig. 6), though this cannot always be quite distinctly seen. The bases of the
mesenteries are broken through by the sphincter, a condition that seems always to be present in the
Zoanthidae with entodermal sphincter. In this region the sphincter has thus the appearance of being
mesoglceal.

The ectoderm of the tentacles has the usual structure. The spirocysts are very numerous;
further, there are numerous thick-walled capsules (length 22 (j) and very few capsules of the same kind
as in the body-wall.

The ectoderm of the oesophagus is fairly high and deeply furrowed or smooth according to
the varying state of contraction and provided with numerous, ca. 24^ long, nematocysts. The ectoderm
of the sulcus is somewhat thicker than in the oesophagus, while the mesogloea is thicker.

The number of mesenteries varies between 36 (34?) and 46, but the latter is only seldom found
and even specimens with 42 mesenteries seem to be scarce. Of the 14 specimens closely examined one
(a small yellowish specimen from the same locality as the colony figured on PI. I, fig. 10), has 34, possibly
36 mesenteries, 3 had 36, 4 had 38, 3 had 40, 2 had 42 and 1 had 46 mesenteries. Below the oesophagus
the macro-mesenteries reach only a short way into the ccelenteron (in specimens not sexually mature).
The longitudinal muscles are distinctly marked but form no or very faint furrows; the parieto-basilar
muscles are weak. The distribution on the body-wall of both kind of muscles is fairly considerable.
The micro-mesenteries are fairly well-developed, in the aboral part of the oesophagus several times
longer than the entoderm of the body-wall is high.

The glandular tract contains numerous thick-walled capsules with distinct basal part to the
spiral thread. They are somewhat broader at the one end and 17 — 22// long and 5^ broad. Further,
it contains capsules with spiral thread of the same appearance as in the body-wall; they seem always
to be scarce and have a length of 36 — 43// and a breadth of 17 — 18^; smaller capsules are also found.
Sometimes I have not found any of the large capsules in the filaments.

The polyps are dioecious.

In the ccenenchyme, which is more or less incrusted, the canals lie nearer to the under than
the upper side.

For systematic remarks see under P. anguicomus.

Parazoanthus anguicomus (Norm.) Haddon &: Shackl.

PI. I, fig. 19; PI. II, fig. 21.

Zoantlius sulcatus Bowerbank 1867. Proc. Zool. Soc. p. 351.

anguicomus Norman 1868. Shetland Report. Rep. Brit. Assoc, p. 310.

The Ingolf-Expedition. V. 4. ^

g ZOANTHARIA

Polythoa (Taeniothoa) anguicoma Andres, Le Attinie 1883 532, 1884. p. 317.

Epizoanthus annricamis var. Verrill, Report Blake. Bull. Harvard. Coll. 1883—85. PI. 8, fig. 6.

Polythoa sp. Ridley, 1886. Proc. Roy. Irish Acad. (2) 4. Ser. p. 617.

Parazoantkus anguicomus (Norm.) Haddon. Trans. Dubl. Soc. 4 (2) 1891. PI. 58, figs. 34—36, PI. 59 figs, n — 12.

Localities: 35045'3o// N-» 74° 4§' W. Verrill 1883-85.

40°oi' N., 70° 22' W. 98 fm. U. S. F. C. St. 2245. 1 colony of 4 specimens together with the typical
Epizoanthus incrustatus (americanus). Fig. 19, PL 1. R. M.

50°57/N., io°46'W. 184 m. Michael Sars Exp. 1910. St. 96. 3 single spec, and 2 small colonies
on Ascidians and Serpula tubes.

Shetland 1899. 1 colony.

Ireland; various specimens from Dublin Museum.

Formerly known localities: Shetlands. W. and S. W. of Ireland. See Haddon 1891.

Dimensions: Column 3 — 5 times as high as broad (Norman). Height of column, when
fairly expanded (in spirit) 13 mm. The specimens from U. S. F. C. Height of column 07 cm., diameter
of capitulum 0-4 cm.

Colour: Pinkish-white (Norman); preserved specimens sand-coloured.

External appearance. This species has been well described by Haddon and Shackleton
(1891). Characteristic are the very deep furrows and the coarse ridges between these in the capitular
region. The number of furrows and ridges seems to be about 18, as stated by Haddon. 6 of the
polyps examined by me had 18 furrows, 1 had 17 and another 19. On small polyps the capitular
furrows are less distinctly seen, but the future appearance of the furrows and ridges may be discerned.
Haddon mentions, that the capitular region is swollen, when contracted. This is easily seen on some
specimens, on others it is less distinct, as was the case with the specimens from the American coast
(fig. 19, PI. I). The oesophagus as well as the hyposulcus is of moderate length. The incrustations
mainly consist of sand-grains but also of foraminifera and sponge-needles. The specimens dredged on
the Michael Sars Expedition were very strongly incrusted and foraminifera also occurred in quantities.

Anatomical description. In 1891 Haddon described the anatomy of this species, but I
am able to supplement his description on some points. The fairly numerous nematocysts with
greatly twisted thread are almost double as long as broad (length ca. 24 /i, breadth ca. 12//). Very
seldom large capsules also occur with slightly twisted thread, length 41—48 by 17—22, which are
equally broad, rounded in the ends, but somewhat broader at the one end. In the sphincter region
the encircling sinus is weak but otherwise it is very well-developed and has the appearance described
by Haddon.

The sphincter has the appearance described by Haddon.

The ectoderm of the tentacles contains numerous spirocysts and some few, ca. 19^ long, thick-
walled capsules. The ectodermal musculature is moderately developed. Incrustations are also found
in the tentacles.

The ectoderm of the oesophagus contains numerous thick-walled, narrow capsules with distinct
basal part to the spiral thread; these are generally 19 ju, sometimes even 24^ long. If present at all,

ZOANTHARIA 59

the nematocysts with twisted thread are very scarce. The mesoglaa is generally thick, so that the
difference in thickness between this and the mesoglcea of the siphonoglyphe, which is somewhat
thickened, is not so great as is usual among the Zoanthidae. The entoderm is thin and several times
thinner than the ectoderm.

I have examined the arrangement of the mesenteries in 3 specimens, namely, 2 of those
represented in fig. 19, PI. I, and 1 from the Michael Sars Expedition. The first had 36 mesenteries,
19 on the one side, 17 on the other, otherwise the arrangement was typical according to the macro-
type, the two mesenteries lying nearest the sulcus, one on each side, being micro-mesenteries. The
second specimen had 38 mesenteries, 18 on the one side, 20 on the other, the third 36 mesenteries,
18 on each side; in the last two cases the mesenteries lying nearest the sulcus were rnaeromesenteries.
As the oesophagus in the aboral part is very wide, the mesenteries there become short, so that in the
glandular tract and genital region they only occupy a small part of the gastrovascular cavity; the
micromesenteries are moderately developed. The longitudinal muscles were strong but no folds
were seen on my specimens; the parieto-basilar muscles were neither broad nor furrowed, they reach a
long way on to the body-wall.

The filaments are very large and strong. The mesoglcea in the glandular region is very thick
both in the intermediate tract and the glandular tract. This is undoubtedly in connection with the
fact, that the mesoglcea of the oesophagus is so thick. The filaments thereby assume a very robust
appearance. The ectoderm of the intermediate and the glandular tracts contains numerous thick-walled
nematocysts, the spiral thread of which is plainly visible. They are much longer than in the
oesophagus (length ca. 26— 29/j, in the North American form they are in greater agreement with the
capsules in the oesophagus, breadth ca. 5 p). Further, I have even observed some few large capsules
of the same appearance as those in the body-wall but larger (length about 31^, breadth half the length).
Both the North American specimens sectioned by me were sexually mature and in both cases
also ovaries were present.

Systematic remarks. As indicated by me in the synomymy list, the variety of C.americanus
figured by Verrill in the Report on the Blake Expedition was no other than Norman's Parazoanthus
anguicomus.

The three species P. haddoni, dixoni and anguicomus are evidently so closely related to each
other, that in many cases it seems difficult to separate them, and especially P. haddoni and dixoni are
very much alike in outer appearance. As Prof. H add on, who had at his disposal a larger material
of P. haddoni and P. dixoni than I have had for investigation and who also several years ago was so
kind as to examine a colony (a coloured one with large polyps) of P. haddoni sent him by me, is of
opinion, however, that they differ, I think I ought to consider them as two different species, though
it is difficult to find really good distinguishing characteristics, especially in material which is not well
preserved. The nematocysts agree quite well in haddoni and anguicomus, whereas they are some-
what but not very much larger in P. dixoni. In a colony of P. dixoni sent me by Prof. Haddon
I found the following series of capsules. The large nematocysts of the body-wall with greatly twisted
thread were 46—53^ long and 19—20^ broad, the smaller ones found in the capitular region were
26—29 f* l°n& and 13— 15 (i broad and occurred in quantities. The thick-walled capsules in the

6o

ZOANTHARIA

oesophagus were 24 — 26^ long. The filaments contained very few capsules 41 ji long and 18 11 broad
like those in the body-wall and fairly many 19 — 22 u long and thick- walled. In a polyp closely examined
by me the number of mesenteries was 42 (20 on the one side and 22 on the other).

In the collections of the Riksmuseum there is a small colony of a Parazoanthns species from
the Faeroes, but badly preserved. The nematocysts mostly resemble those of P. kaddoni, but might
quite well belong to P. anguicomtcs though not to P. dixoni, as they agree with the shortest ones in
P. haddoni and anguicomus, while those of dixoni agree better with the longest ones. A transverse
section of the body-wall of this form is given in fig. 6, PI. VII, of this paper.

Appendix.

During the printing of this work a paper has appeared dealing with the genus Epizoauthus
(Lwowsky: Revision der Gattung Sidisia Gray (Epizoanthus Auct.), Zool. Jahrb. Abt. Systematik
Bd. 34, pp. 557 — 614, 1913). As this paper among other things sets up a new diagnosis for the genus
I wish to discuss here the extent of this genus.

With regard first of all to the name, the author has replaced Epizoanthus with Sidisia, a change
that would be justifiable according to modern rules of priority, if the type of Sidisia, S. darlcsi, were
iu reality identical with E.incriistatus. Haddon and Shackleton (1891) certainly state, that this is
the case, but they nowhere indicate, that they have had type specimens of S. barlesi for investigation.
For this reason, as also that the Zoanthidae are difficult to determine from outer characteristics, I have
above used the name Epizoanthus instead of Sidisia. Moreover I am in agreement with Haddon (1891,
p. 634): "We do not propose to keep the name Sidisia for the genus, although it has priority and for
this reason; it was solely erected for a species which is only a variety of an older form; and the name
has only been occasionally retained for this variety of that particular species, whilst Epizoanthus has been
universally adopted for the more typical forms of this genus. Both names were originated by Gray
and we have therefore less hesitation in keeping to the latter".

In his diagnosis of the genus Sidisia Lwowsky states, that the sphincter in its proximal part
may be entodermal as also that an encircling sinus may occasionally be present; he relies here on his
investigation of S. gracilis. But in my opinion S. gracilis is in all probability not a Sidisia but a Para-
zoanthus species. So far as I can find, namely, the sphincter figured of E. gracilis is not a mesogloeal
but an entodermal structure. That it seems mesoglceal in the distal part is due to this, that the
section has cut through not only the body-wall but also a mesentery. And since the entodermal
sphincter in the genus Parazoanthus becomes mesoglceal from cutting through the mesoglcea of the
mesenteries, a great part of the sphincter in sections which just meet the mesenteries may have the
appearance of being a weak mesoglceal sphincter. Such figures, like that drawn by L, wow sky for

ZOANTHARIA 6l

S. gracilis, I have often obtained both in Isozoanthus and Parazoanthns species. It is difficult especially
to obtain good figures of the entodermal sphincter in those polyps where the mesenteries lie very
close together, for in such cases the section cuts not only the body-wall but also at the same time a
mesentery. As E. gracilis is a form with small polyps and with numerous mesenteries, the section has
certainly at one and the same time cut through the body-wall and mesenteries. I thus believe, that
S. gracilis is a Parazoanthns species (a fact that Lwowsky in a letter to me seems willing to accept).
Under such circumstances the additions in the diagnosis which Lwowsky makes with regard to the
sphincter and encircling sinus must be dropped, for the indication of an encircling sinus, which the
ectodermal canals are said to form in S. ialanorum, has little resemblance to a true encircling sinus
especially in the upper part of the polyp.

Thus the assumption, that an encircling sinus occurs in Epizoanthus, must also be rejected,
though it is not inconceivable theoretically, that such may occur there. When we see, namely, that
the macrocnemic Zoanthidae with entodermal sphincter may have (Parazoanthns) or lack (Isozoanthus)
an encircling sinus, it is quite possible, that the same condition may be present in the macrocnemic
Zoanthidae with mesoglceal sphincter. In this case it might be advisable to set up a new genus for
forms with encircling sinus, distinct from Epizoanthus. Nevertheless .5". gracilis cannot be taken as a
type for this conceivable genus and just as little, it seems to me, S. balanonuii.

Lwowsky states, that a specimen of Epizoanthus norvegicns examined by him had a brachyc-
nemic arrangement of the mesenteries (1. c. p. 608) and thinks it probable, that H add on and Shack-
leton (1891), just on account of the external habitus and the appearance of the sphincter, had concluded
that this species was an Epizoanthus. Since H addon and Shackle ton in their short notice on this
species remark upon the appearance of the incomplete mesenteries, they have certainly also examined
the arrangement of the mesenteries. The specimens I have examined here above show a macrocnemic
arrangement; 2 other specimens, of which I made sections, had the same arrangement. Lwowsky's
specimen has thus — unless some mistake of locality has taken place — been a malformation, which
sometimes occurs both in brachyeuemie and macrocnemic Zoanthidae, the brachycuemic showing a
macrocnemic type and the macrocnemic a brachycnemic, but only exceptionally, so far as I know
(Polytlioa caribcea), on more than on side of the bod}' (Carlgren: Beobachtungeu iiber die Mesen-
terienstellung der Zoantharien etc. Festskrift for Lilljeborg 1896, fig. 6a PI. 8; Duerden: Jamaican
Actiuiaria PI. 1, Zoantheae Sc. Trans. R. Dublin Soc. 6 (2) 1898 p. 331; this work p. 34). Further, dis-
arrangement of the mesenteries sometimes occurs (Carlgren 1896 1. c. PI. 8, fig. 5 a, 7). That a
brachycnemic species should occur in Trondhjem Fjord is indeed little conceivable, since we know of
no brachycnemic forms from European seas; these belong to tropical and subtropical seas. In any case
Lwowsky's colony of E. norvegicus certainly merits closer examination.

Finally, I wish to point out an oversight of Lwowsky, which may possibly be misleading for
his readers. On p. 568 he identifies "the reflected entoderm" with the cnido-glandular region instead
of with the ciliated tract of the filaments (cf. Haddon & Shackletou's figs. 1, 6, PI. 60. 1891).

I cannot conclude this appendix without emphasizing, that our investigations on the various
Zoanthidae species require to be extended, if we are to reach more accurate knowledge as to whether

62 ZOANTHARIA

a form has to be regarded as a special species or as a growth form or variety. It is very probable
indeed, that the Zoanthidae display great variation during growth, though the extent of this variation
cannot be judged without exact investigation (it can hardly be more than supposed), but it also
seems to me, that the number of species of Zoanthidae is large. I emphasize this especially with
regard to Lwow sky's combining Zoanthidae described as separate species into one species Sidisia
fatna. It is certain, that this requires revision. Even if the nematocysts in the body-wall are
difficult to find or are lacking, yet the nematocysts in the filament especially would give valuable
information.

4

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— Uber einige norwegische Actinien. Isis 1848 p. 236.

Gosse, P. H., Actinologia Britannica. A history of the british Sea-Anemones and Corals 1S60.

H addon, H. & Shackleton. A. W., A revision of the British Actiniae P. 2. Zoantheae. Sc. Trans. R. Dublin Soc. 4(2) 1891.
Koren, I. and Danielssen, D. C, Fauna littoralis Norvegiae III 1877.

Marenzeller, Emil E., Die Coelenteraten etc. der K. K. oesterreichish-ungarischen Nordpol-Expedition. Denkschr. Akad.
Wiss. Mat. -Nat. Classe. 35 p. 357, Wien 1878.

— Anthozoen in Die Internationale Polarforschung 1882-83. Die oest- Polar Station Jan Mayen. Beobachtungsergebnisse

herausg. v. d. Akad. Wiss. Wien Bd. 3. 1886.
Mortensen, T., Smaa faunistiske og biologiske Meddelelser. Vidensk. Medd. Naturh. Forening. Kjobenhavn 1897 p. 311.
Norman, A. M., Last Report on Dredging among the Shetland Isles. Rep. Brit. Assoc, p. 232. 1868.
Parker, G. H., Synopsis of North-American invertebrates. The Americ. Naturalist. 34. 1900 p. 787.
Sars, M., Beretning om en i Sommeren 1849 foretagen Reise i Lofoten og Finmarken. Nyt Mag. Natuv. 6(2) 1851 p. 122.

— Oplysuinger om nogle Coelenterater fra Norges Kyster. Forh. Skand. Naturf. Mode Kjobenhavn. i860 p. 690.

— Om nogle nye eller lidet bekjendte norske Coelenterater. Forh. Vid. Selsk. Christiania i860.

Verrill, A E., Revision of the polypi of the Eastern Coast of the United States. Mem. Boston Soc. Nat. Hist 1S64 p. 1.

— On the Polyps and Echinoderms of New England. Proc. Boston Soc. Nat. Hist. 10 1866, p. 333.

— Report upon the Invertebrate Animals of Vineyard Sound. Rep. U. S. Couim. of Fish and Fisheries 1873 p. 275.

— Notice of the remarkable Marine Fauna occupying the outer banks off the southern coast of New England. Americ.

Journ. Sc. (31 23 p. 135; ibidem. No. 5. p. 309.

— Report on Anthozoa and on some additiona1 species dredged by the Blake in 1877 — 1879 etc. Bull. Mus. Comp. Zool.

Cambridge Mass. n 1883 (85).
Notice of the remarkable marine Fauna occupying the outer banks off the southern coast of New England etc. U. S.
Fish. Coram. Rep. for 18S2 p. 641.

— Notice of the remarkable marine Fauna occupying the outer banks off the southern coast of New England No. 11.

Americ. Journ. Sc. (3) 29. 1885.
Results of the Explorations made by the steamer Albatross off the northern coast of the United States in 1S83, 8. U. S.
Fish. Comin. Report for 1883. 1885 p. 535.

EXPLANATION OF LETTERS.

c. eutieula.

d. detritus,
di. diatoms.

eb. ectodermal bay.

ek. ectoderm,

en. entoderm,

enc. encircling sinus,

i. incrustations.

if. incrustations of foraminifera.

is. incrustations of sand.

iss. incrustations of spicula.

m. mesoglcea.

mc. mesogleeal-cells.

me. mesenteries.

mi. cell-islets in the mesogloja.

ml. lacunae in the mesoglcea.

mn. muscles.

n. nematocysts.

rm. transverse muscles.

z. zooxanthellae.

ABBREVIATIONS IN THE TEXT.

N. N. A. E. : Norwegian North-Atlantic Expedition.

R. M. : Riksmuseum of Stockholm.

U. S. F. C. : United States Fish Commission.

Ups. M., U. U. Z. M. : Zoological Museum of the university Upsala.

Plate I.

Plate L

Fig. i. Isozoantkus arboresceus 2/, (from Mortsund).

— 2. r/i (from Tranodybet).

— 3, 4. danicus 2/j on oyster shells. In fig. 3 also on the right side an Ascidiau.
5. bulbosus 2/I (Romer & Schandinn).

— 6. — 2/1 (from Ingolf Exp. St. 104).

— 7. magninsulosus 1/I (from Ingolf Exp. St. 10).

— 8. Epizoanthus pagiiriphilus I/I (from Michael Sars Exp. 1900).

9. Parazoanthus haddoni on sponges r/i (from N. N. W. of Bergen. Uddstrom R. M. No. 270).

— 10. — Vi (from N. W. of Bergen. Mattsson 1880 R. M. No. 740).

— 11. — on sponges '/i (from N. N. W. of Bergen. Uddstrom R. M. No. 270).
- 12. Epizoanthus norvcgicus (from Trondhjem Fjord).

— 13. danielsseni 2\x (from Sophia Exp.).

— 14. erdmauni 1II (from Spitzbergen Exp. St. 42).

— 15. — danielsseni a little magnified (from Spitzb. Exp. St. 42).

— 16. — erdmanni +/i capitulmn from the oral side.

— 17. — erdmanni 1/1 (from Greenland Exp. 1899).

— 18. Isozoanthus nmltinsjtlosns 2/i (from Ingolf Exp. St. 51).

— 19. Parazoanthus anguicomus 2/t (= E. americanus var. Verrill U. S. F. C. St. 2245).

r

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Plate II.

Plate II.

Fig. i — 5. Epizoanthus glacialis (fig. 1 from Umenak ''S/,; fig. 2 from Jan Mayen 2/i> fig- 3 from Norw.
Nord. Atl. Exp. St. 164 (type) 2/I; fig. 4 from 0gsfjord, Loveu 2/x; fig. 5 from Umenak 25 fms. 2'S/Z.
6. Epizoanthus danielsseni (from Norw. N. Atl. Exp. St. 164) about 2/i-

— 7. lindahli var. nordgaardi about 2/T.

— 8. — abyssorum about 2/l.

— 9. danielsseni var. loveni */,.

— 10. beerenislandicus 'lz.

— 11. lindahli (from Baffius Bay, Lindahl) enlarged somewhat more than 2 times.

— 12. — — (from Michael Sars Exp.) 2lt.

— 13. (from Ingolf Exp. St. 32) about 2/i-

— 14. bulbosus dissected specimen showing the mesenteries (from Ingolf Exp. St. 104

about 2/i)-

— 15. Epizoanthus bulbosus (from Ingolf Exp. St. 104 about 2ll).

— 16. (from Ingolf Exp. St. 32 about 2/\).
Fig. 17. Epizoanthus davisi (from Ingolf Exp. St. 32 about 2-5/i)-

— 18. erdmanni var. aurivillii (from Kvenangen) about 2-5/t.

— 19. Isozoanthus dubius (from Ingolf Exp. St. 45) about 2/x.

— 20. islandicus (from Ingolf Exp. St. 90) about 2jI.

— 21. Parazoanthus anguicomus (from Dublin Museum) about I-75/i-

— 22. Epizoanthus norvegicus (from Troudhjem Fjord, Bergen Museum) I-5/i, on the left a large

double polyp.

— 23. Epizoanthus korcni (from Ingolf Exp. St. 144) 2jl.

— 24. — erdmanni (from Iceland Ofjord) about 2/1.

— 25. Isozoanthus ingolji (from Ingolf Exp. St. 27) about 2/I.

— 26. Epizoanthus incrusfatus (R. M. 23. 5. 1888) about ws/i-

— 27. Isozoanthus arborescens (from Ingolf Exp. St. 97) about I-7S/I.

— 28 — 29. Epizoanthus erdmanni var. aurivillii (from Kvenangen) 2"2S/I.

The InsSolf Expedition V.4.

Carlgren Zoruitharia. PI. II.

If. llobngrm phot

Ljnstr A.B, Lagrelius t> Wcslplwil Stockholm

Plate III,

Plate III.

Vertical sections through the sphincter muscles. In the figs, i — 3, 5 the distal part of the sphincter is

turned upwards, in the figs- 4 and 6 downwards.
Fig. 1 of Epizoanthus abyssorum 2/3 I.

— 2 - — beerenislandicus 4/3.

3 - norvegicus (from Skarnsound) 2/3.

— 4 - — roseus 2/3.

— 5 - Isozoaiitlnts arborescens (from Ingolf Exp. St. 97) V3.

— 6 - ParazocDitlius haddoni (from N. W. of Bergen, Mattson 1880 2/3).

1 Magnifications refer to Reichert's system "Austria". Figures drawn on the level of the microscope's foot.

The [n^olf Expedition V.4.

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Plate IV.

Plate IV.

Fig. i. Epizoanthtis beerenislandicus. Transverse section through the body-wall 4/3 1.

— 2. — glacialis. Vertical section through the sphincter (from Norw.. N. Atl. Exp.) 2/3.

— 3. crdmanni — (from Lyngen, Nordgaard) 4/0.

— 4. koreni. Transverse sections through the body-wall 4/3.

— 5. lindahli. (from Baffins Bay) 4/3.

— 6. glacialis — upper part. -t/3.

— 7. glacialis lower part. */3.

' Cf. PI. III.

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Plate V.

Plate V.

Transverse sections through the body-wall, figs, i, 3 — 7 in the region of the oesophagus. Entoderm not

drawn in figs. 3, 5, 6.

Fig. 1 of Epizoantlms danielsseni (from Spitsb. Exp. St. 42) +/3 1.

— 2 - norvegicus, capitular region (Trondbjem Fjord, Ostergren) 4/3.

3 - ( ) Vs-

— 4 of Epizoantlms crdmanni (Lyngen, Nordgaard) 4/v

5 - var. aurivilli (Finmarken, Goes & Malmgren) +/3.

— 6 - — roseus 4/3.

— 7 - — abyssorum 4/3.

> a. pi. in.

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Plate VI.

Plate VI.

Transverse sections of the body-wall figs, i, 3, 5 in the region of the oesophagus; figs. 2, 4 in the enido-
glandular tract of the filaments, fig. 6 in the hyposulcus region (Magnification ■».', Reichert's "Austria";
the figures drawn on the level of the microscope's foot; fig. 1 same magnification but with drawn out

tube. Entoderm not drawn in figs. 1 — 4).

Fig. 1 of Isozoanthus bulbosus (from Ingolf Exp. St. 104).

— 2 - arborescens (from Mortsund, Nordgaard).
3 - multinszilosus (from Ingolf Exp. St. 51).

— 4 - — magninsulosus.

— 5 - - -

— 6 - ingolfi (from Ingolf Exp. St. 27).

Thelngolf Expedition V.4.

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Plate VII.

Plate VII.

Transverse sections through the body-wall in the region of the oesophagus; fig. 5 in the region of the
cnido-glaudular tract of the filaments, figs. 1—4 magnification 2/7 Reichert's "Austria". Figures drawn

on a level with the stage of the microscope.

Fie. 1 of Isozoanthus davisi.
— 2 - — islandicus.

— dubius.

— dcmicus.

5 Parazoanthus haddoni (from N. W. of Bergen, Mattson 1880) 2/3 with drawn out tube.

6 - — ? (from the Faeroes) 2/3 with drawn out tube.

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THE INGOLF-EXPEDITION

1895 — 1896.

THE LOCALITIES, DEPTHS, AND BOTTOMTEMPERATURES OF THE STATIONS.

Depth

Depth

Depth

Station

Nr.

Lat. N.

Long. W.

in
Danish
fathoms

Bottom-
temp.

Station

Nr.

Lat. N.

Long.W.

in
Danish
fathoms

Bottom-
temp.

Station

Nr.

Lat. N.

Long. W.

in
Danish
fathoms

Bottom-
temp.

I

620 30'

8° 21'

132

7°2

24

630 06'

560 00'

1 199

2°4

45

6i° 32'

9° 43'

643

4°i7

2

630 04'

90 22'

262

5°3

25

63° 30'

54° 25'

582

3°3

46

61° 32'

11° 36'

720

2°40

3

°3° 35'

io° 24'

272

o°5

63° 5i'

53° 03'

136

47

61° 32'

13° 4o'

95o

3°23

4

640 07'

ii° 12'

237

2°5

26

&3° 57'

52° 41'

34

o°6

48

61° 32'

15° 11'

1 150

3°i7

5

640 40'

12° 09'

155

64° 37'

54° 24'

109

49

620 07'

150 07'

1120

2°gi

6

63° 43'

14° 34'

90

7°o

27

64° 54'

55° JO-

393

3°S

50

620 43'

15° 07'

1020

3°i3

7

63° 13'

15° 41'

600

4°5

28

65° 14'

SS" 42'

420

3°5

5i

64° 15'

14° 22'

68

7°32

8

63° 56'

240 40'

136

6°o

29

65° 34'

54° 31'

68

0°2

52

63° 57'

13° 32'

420

7°87

9

640 18'

27° 00'

295

5°«

3°

66° 50'

54° 28'

22

i°o5

53

63° 15'

15° 07'

795

3°°8

IO

640 24'

28° 50'

788

3°5

31

66° 35'

55° 54'

88

i°6

54

63° oS'

15° 4o'

691

3°9

ii

64° 34'

31° 12'

1300

i°6

32

66° 35'

56° 38'

3tS

3°9

55

63° 33'

1 50 02'

316

5°9

12

64° 38'

32° 37'

1040

o°3

33

67° 57'

55° 3°'

35

o°8

56

64° 00'

■5° 09'

68

7°57

'3

64° 47'

34° 33'

622

3°o

34

65° 17'

54° 17'

55

57

63° 37'

13° 02'

35o

3°4

14

64° 45'

35° 05'

176

4°4

35

65° 16'

55° 05'

362

3°6

58

64° 25'

12° 09'

211

o°8

15

66° 18'

25° 59'

330

-o°75

36

6i° 50'

56° 21'

1435

i°5

59

65° 00'

11° l6'

310

— o°i

16

65° 43'

260 58'

250

6°i

37

60° 17'

54° 05'

1715

i°4

60

65° 09'

12° 27'

124

o°9

17

620 49'

260 55'

745

3°4

38

59° I2'

5i° 05'

1870

i°3

61

65° 03'

13° 06'

55

o°4

iS

61° 44'

300 29'

"35

3°°

39

62°oo'

22° 38'

865

2°9

62

63° 18'

I90 12'

72

7°92

19

6o° 29'

34° 14'

1566

2°4

40

620 00'

21° 36'

845

3°3

63

62° 40'

I90 05'

800

4°o

20

58° 20'

400 48'

1695

i°5

4i

61° 39'

17° 10

1245

2°0

64

62° 06'

1 90 00'

1041

3°i

21

58°oi'

44° 45'

1330

2°4

42

6i°4i'

10° 17'

625

o°4

65

61° 33'

190 00'

1089

3°o

22

580 10'

48° 25'

1845

i°4

43

61° 42'

IO° 11'

645

o°o5

66

6i°33'

20° 43'

1128

3°3

23

6o° 43'

56°oo'

Only the

Plankton-Net

used

44

6i°42r

9° 36'

545

4C8

67

61 ° 30'

22° 30'

975

3°o

Station
Xr.

hat. N. Long.W.

6S
69
70
71
72
73
74

75
76
77
73

79
80
81
S2
83

84

S5
86

37
88

39
90

9i

Depth

in
Danish
fathoms

Bottom-
temp.

62° 06'

620 40'
630 09'
63° 46'
630 12'
62° 58'
620 17'

6i°57'
6i°2S'
6i°2S'
6o° 50'
6o° 10'
6o° 37'
60° 52'

6l°02'

6i°44'
6i°55'

620 25'
62° 36'
62° 36'
620 58' .

63°2I'

650 03V,

65° 02'.,

640 58'
64° 45'
640 45'
64° 44'

22°

3"

22°

17

22°

05

22°

03

23°

04

23°

28

24°

36

25°

35

25°

06

26°

25

260

5°

26°

59

27°

52

2S0

58

290

32

270

00

270

28

28°

3°

26°

01

25°

3°

25°

24

25°

21

230

47

<)

23°

56

2

24°

25

27°

20

290

06

3i°

00

843
5S9

'34
46

T97
4S6

695
761
S29
780
806
951
799
653
935
485
S24
912
472
401

6.33
170

76
no

76

310

56S

1236

Station

Nr.

Lat. N.

3°4

3°9
7°o

6°7
5°5
4°2

4°3
4°i
3°6
4°5
4°4
4°o
6°i
4° 1
3°5

4°8

6°9
8°4
4°4
3°'

92
93
94

95
96

97
98

99
too

IOI

102

103

104

105

106

107

108

109

no
in
112

"3
114

115
116
117

64° 44'
64° 24'
64° 56'

65° 31'

65° 14'
65° 24'
65° 28'
65° 33'
66° 13'
66° 23'
66° 23'
66° 23'
66° 23'
66° 23'
65° 34'
65° 34'
65° 29'

65° 33'
65° 30'
65° 29'
66° 44'
67° 14'

&7° 57'
69° 31'

7o° 36'
70° 50'
70° 05'
69° 13'

Long.W.

Depth

in
Danish
fathoms

32 52
35° 14'
36° 19'

3°° 45'
3°° 39
29° 00'

27° 39'
26=27'

25° 53'

14° 02'

12° 05'

IO° 26'

S°52'

7° 25'

7°3i'

S°54'

8° 40'

10° 28'

12° 00'

13° 25'

"°33'

8° 48'

6° 44'
7° 06'

7° 29'
8°29'
8° 26'
8° 23'

976
767
204
213
752
735
45o
138
187
59
537
75o
579
957
762

447
466

492

97

3S

781

860

1267

1309

773
S6

37i
1003

Bottom-
temp.

i°4

i°46

4°.

2°I
I°2

5°5

5°9

6° 1

o°4
o°7
-o°9
o°6
-i°i
-o°8
-o°6

o°3
r°i

i"5
-o°S
-o°9
-i°i
-i°o
-i°o

o°i
-o°4

i°o

Station

Nr.

11S
119
120
121
122

123
124

125
126
127
12S
129
130
131
132

133
134
135
136
'37
13S

139
140
141
142

143
144

Lat. N.

68° 27

67° 53
67° 29

66° 59
66° 42

66° 52
67° 40'
68° 08
67° 19
66° 33
66° 50

66° 35
63° 00
63° 00'
63° 00
63° 14
62° 34
62° 48
63° 01

63° H
63° 26

63' 36
63° 29
63° 22
63° 07
62° 58
62° 49

Long.W.

Depth

in
Danish
fathoms

8°

20

10°

!9

n°

32

13°

11

14°

44

15°

40

15°

40

16°

02

|

15°

52

20°

05

20°

02

23°

47

!

20°

40

I9°

09

I7°

04

11°

24

IO°

26

9°

48

9°

11

8°

3i

7°

56

7°

3°

6°

57

6°

58

7

05

7°

09

7 =

12

1060

IOIO

8S5
529
115
145
495
729

293

44
194
117
338
69S

747
230

299
270

256
297
47i
702
780

679
5S7
388
276

Bottom-
temp.

— iuo

— i°o

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THE DANISH INGOLF-EXPEDITION.

HITHERTO PUBLISHED:

1899. Vol. I, Part I. 1. Report of the Voyage by C.F Wandel (1 plate)

2. Hydrography by Martin Knudsen (34 plates)

1900. — Part II. 3. The deposits of the sea-bottom by O. B. Boeggild

(7 charts)

4. Current-bottles by C. F. Wandel (1 plate)

1899. Vol. II, Part I. The ichthyological results by Chr. Liitken (4 plates) . . .

1899. — Part II. On the Appendices genitales (Claspers) in the Greenland-

Shark, Somniosus microcephalus (Bl. Schn.), and other Sela-
chians by Hector F. E.Jnngersen (6 plates)

1900. — Part III. Nudibranchiate Gasteropoda by R. Bcrgh (5 plates)...
1904. — Part IV. The North-European and Greenland Eycodinse by

Adolf Severin Jensen (10 plates)

1912. — Part V. Lamellibranchiata, Part I, by Ad. S. Jensen. (4 plates

and 5 figures in the text)

1899. Vol. Ill, Part I. Pycnogonidse by Fr. Me inert (5 plates)

1908. Part II. Crustacea Malacostraca, I: Decapoda, Euphausiacea,

Mysidacea by H.J. .Hansen (5 plates)

1913. — Part III. Crustacea Malacostraca, II: Tanaidacea by H.J.Hansen

(12 plates)

1903. Vol. IV, Part I. Echinoidea, Part I, by 77/. Mortensen (21 plates)

1907. Part II. Echinoidea, Part II, by 77/. Mortensen (19 plates)

1904. Vol. V, Part I. Pennatulida by Hector F. E.Jnngersen (3 plates)

1912. Part II. Ctenophora by 77/. Mortensen (10 plates and 15 figures

in the text)

1912. Part III. Ceriantharia by Oskar Carlgren (5 plates and 16 figures

in the text)

1913. — Part IV. Zoantharia by Oskar Carlgren (7 plates and 6 figures

in the text)

1902. Vol. VI, Part I. Porifera (Part 1), Homorrhaphidse and Heterorrhaphidse
by Will. Limdbeck (19 plates)

1905. Part II. Porifera (Part 2), Desmacidonidae (Pars) by Will. Lundbeck

(20 plates)

1910. — Part III. Porifera (Part 3), Desmacidonidse (Pars) by Will. Lundbeck
(11 plates)

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