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Digitized by the Internet Archive
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http://www.archive.org/details/memoirs3/harv

MEMOIRS

OF THE

MUSEUM OF COMPARATIVE ZOOLOGY

AT

HARVARD COLLEGE.

VOL. XXXVI.

CAMBRIDGE, U.S.A.
PRINTED FOR THE MUSEUM.
1909.

University Press:
Joun WIitson anv Son, CamprinGe, U.S.A.

CON TEN Ts.

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE
EASTERN TROPICAL PACIFIC, in charge of ALEXANDER Aaassiz, by the U.S.
Fish Commission Steamer ‘‘ Albatross,” from October, 1904, to March, 1905, Lieut.
Commander L. M. Garrett, U. S. N., Commanding. XVI. TuHE Mepusaz. By
Henry B. Bicerow. 243 pp., 48 Plates. February, 1909.

Memoirs of the Museum of Comparative Sodlogy
AT HARVARD COLLEGE.

Vou. XXXVII.

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE
EASTERN TROPICAL PACIFIC, IN CHARGE OF ALEXANDER AGASSIZ,
BY THE U. S. FISH COMMISSION STEAMER “ALBATROSS,” FROM
OCTOBER, 1904, TO MARCH, 1905, LIEUT. COMMANDER L. M. GARRETT,
U.S. N., COMMANDING.

XVI.

THE MEDUSAE.

By HENRY B. BIGELOW.

WITH FORTY-EIGHT PLATES.

[Published by permission of GeorGe M. Bowers, U.S. Commissioner of Fish and Fisheries.]

CAMBRIDGE, U.S. A.:
Printed for the sAuseum.

FEBRUARY, 1909.

+ I
PIay ©
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TABLE OF CONTENTS.

INTRODUCTION

Scyphomedusae

Charybdeida .

Charybdeidae : :
Charybdea Péron et cage
Charybdea rastonii Haacke

Coronata

Periphyllidae é

Periphylla Steenstrup :
Periphylla hyacinthina Sieonetep :
Periphyllopsis Vanhoffen . :
Periphyllopsis braueri Vanhoffen
Atorellidae :

Atorella Vanhoffen .

Atorella vanhéffeni, sp. nov. .
Ephyropsidae

Nausithoé Kolliker

Nausithoé punctata Kolliker
Nausithoé rubra Vanhoffen
Atollidae

Atolla Haeckel ;

Atolla wyvillei Haeckel .

Discophora

Pelagia Péron et Teens
Pelagia panopyra Péron
Poralia Vanhoffen :
Poralia rufescens Vanhéffen .

Craspedotae .
Narcomedusae .

Cunanthidae .

Cunoctantha Haeckel .

Cunoctantha octonaria MeCrady

Cunoctantha tenella, sp. nov.

Cunina Eschscholtz

Cunina globosa Eschscholtz

Cunina peregrina, sp. nov.

Cunina species?

Solmissus Haeckel ar

Solmissus marshalli Agassiz and
Mayer

2 09 OO
ANGS

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45

q

2

or
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at

It

oS
— b

1
a

or Ot S
on

&

Solmissus incisa Fewkes

Aeginidae

Aegina Eschscholtz

Aegina citrea Eschscholtz

Aegina alternans, sp. Nov.

Solmundella Haeckel .

Solmundella bitentaculata Gage et
Gaimard :

Aeginura Maaelel

Aeginura grimaldii Maas

Solmaridae 500 CNS won eed

Pegantha Haeckel ..- +--+: >

Pegantha martagon Haeckel .

Pegantha triloba Haeckel .

Pegantha smaragdina, sp. Nov.

Development of Pegantha smaragdina

Pegantha laevis, sp. nov.

Trachomedusae

Petasidae .

Gossea L. Agassiz

Gossea brachymera, sp. Nov.

Gonionemus A. Agassiz . :

Gonionemus suvaensis Agassiz and
Mayer :

Olindias F. Miller

Olindias singularis Browne

Geryonidae

Liriope Lesson 5 oe

Liriope tetraphylla Chamisso

Liriope species? rs

Geryonia Péron et Lesueur

Geryonia proboscidalis Forsk: al.

Trachynemidae

Aglaura Péron et Lesueur .

Aglaura —hemistoma Péron et
Lesueur

Aglantha Hae ‘eel: ats

Aglantha digitale var intermedia,
var nov.

Tetrorchis, gen. nov. .

8 CONTENTS.

PaGE PAGE
Tetrorchis erythrogaster, sp. nov.. . 124 Sarsia coccometra, sp.nov. ... . 179
Amphogona Browne . . . 5 8 pes Sarsia resplendens, sp. nov. . . . . 181
Amphogona apsteini V anhéffen 2s, 126 PurenaHaxtlaubig vans ies) omen eO
Rhopalonema Gegenbaur . . . . . 127 Purena brownei, nom.nov. ... . 183
Rhopalonema velatum Gegenbaur . 129 Ectopleura lL. Agassiz ... . = . 184
Rhopalonema funerarium Vanhoffen 132 Ectopleura ochracea A. New Be Jey
Colobonema Vanhéffen .... . . 182 Pennaria Goldfuss . . . . . 185
Colobonema sericeum Vanhdéffen . . 133 Pennaria vitrea Agassiz and Meee 186
iRectyllidacmy mamomemct fear mete ieLos Pennaria species?, = 2 = «1 -) -a-leloa
Crossota\Vanhoffen= . - = . . . = 184 Cladonemidae <= <5) = sostmemimmelonl
Crossota brunnea Vanhoffen . . . . 135 Zanclea Gegenbaur. .... ... 187
IS EMTO EISCEY | GGG. oho co alone oF JlGty Zanclea gemmosa McCrady ... . 188
Halicreas Fewkes . .. . we 138 Cytaeidae 2126) <1 lo mcieciemC mmo
Halicreas papillosum Vanhiffen eel 3sS Cytaeinae.. . i. o 0 a ao HE)
Homoeonema Maas. ...... . 141 Cytaeis Hgoheckolel eto 6 6 le)
Homoeonema alba Vanhéffen. 5 odo le Cytaeis vulgaris Agassiz and Mayes 190
Homoeonema racovitzae Maas. . 144 Dendroclavinae . 5.59. <3 cameos
Homoeonema species? .... . . 145 ymnorea; Mayer. 3). . 2.) emule
Halitrephes, gen. nov. . .... . 145 Lymnorea alexandri Mayer . . . . 198
Halitrephes maasi, sp.nov. . . . . 146 Bougainvilleidae - . 9. =.) anemelcD
Iceptomedusacmemancme yeneiecne ace 4i Jougainvillea fulva Ageeriz and
aodiceidacsn\ emcee ok ee lS. WEN OUIoNOdNoao 0 0D oo 5 2 SE)
Ptychogena A. ikeaeete Secon en cs) Amphinemidae . 95.) lene meme
Ptychogena erythrogonon, sp. nov. . 150 Amphinema Haeckel ...... . 198
Hucopld gemma ketae ie teed Be LO Amphinema australis Mayer. . . . 199
Phialium Haeckel . ....:.. 158 Amphinema turrida Mayer ... . 200
Phialium duodecimalis A. Agassiz . 154 Stomotoca, lL. Agassizi 2.) -)uenemesulle
Phialidium Leuckart . ..... . 155 Stomotoca divisa Maas . .... . 203
Phialidium discoida Mayer ... . 155 Tiaridae: .. «3 © (s(t) Slice emeemme EE
PhialucinmMaastee. psi. + 8c eee Lor Pandea Lesson . -:. . 205
Phialucium comata, sp. noy.. . . . 158 Pandea violacea Agassiz a Maye er. 205
Hirene Eschscholtz. ...... . 160 Tiara Lesson... «7 seu tere)
Eirene medusifera, sp.nov. ... . 161 Tiara papua Lesson . . 2. . 23 20m
Eirene viridula Eschscholtz . . . . 163 Turris Lesson <.. .. e-em Le)
Mitiminge sewer etyeae sees es Od Turris fontata, sp.nov... ... . 209
Eutima MeCri adys SON ub foeey once (iis5 Bythotiaridae’ ~ . . 5.) © cueremmmeculicy
Eutima levuka Agassiz and Mave oT. 0 G5, Sibogita Maas . . . . <1.) memes
Eutimalphes Haeckel ..... . 166 Sibogita simulans, sp.nov. . . . . 213
Eutimalphes scintillans, sp. nov. . . 167 Heterotiara Maas. . . . 2. cel
Octocanninae’ 36. wes 2.) 2 168 Heterotiara anonyma Maas ... . 216
Octocanna Haeckel. ....... 168 Willidao semi io Ge willis’
Octocanna polynema Haeckel . . . 169 Proboseidaetyla Brande Bice eto oy culls}
Aequoridae .... aie this) are) LLCO Proboseydactyla ornata var. stoloni-
Aequorea mi exounatyluin Br: nate . 174 fera Maas Seo on 2A)
Aequorea coerulescens Brandt . . . 177 | Geographical aisubution Set vy ce
Anthomedusae .. .... .,. . 179 Bathymetric range . ....... . 228
Codonidae 6 ow os w « « « LT9 | Bibliography <<) </vcmemencue- meaner
Barsia Lesson ......... . 179 | Explanation of plates “<). 2 2 a senmedth

INTRODUCTION.

TuE collection of Medusae obtained during the cruise of the “ Albatross”
in the Eastern Tropical Pacific in 1904-05 is to be ranked as among the more
important of recent years. Not only is the number of species large (72), but
it includes two new intermediate genera of great interest from their system-
atic relationships, as well as excellent examples of several previously little-
known genera, such as Atorella, Periphyllopsis, Aeginura, Pegantha, Halicreas,
Homoeonema, Sibogita, and Heterotiara. The number of new species (17)
may seem comparatively small, but it must be remembered that the greater
part of the collection consists of holoplanktonic forms, organisms now known
to be of general distribution in the warmer waters of all oceans. The fact
that the greater portion of the cruise led through an oceanic area far from
land no doubt explains the total absence of rhizostomes from the collection.
Intermediate genera, both craspedote and acraspedote, are especially well
represented.

Among the features of morphologic interest I may call attention here to
the discovery of a new halicreid, Halitrephes, with numerous radial canals ;
of a new trachynemid, Tetrorchis, with four gonads on the subumbrella ;
of a Cunina lacking peripheral canal system ; of a Cunoctantha, C. denel/a, in
which, unlike previously known members of this genus, a canal system is
well developed ; and of the development of free medusa buds in the region of
the gonads in a new species of Hirene. From the developmental standpoint
the discovery of an almost complete series of stages in the development of
Pegantha smaragdina is of especial importance, since nothing was previously
known of the early stages of this interesting genus; and of equal importance
is the demonstration of the occurrence of internal budding in Cunina and
Pegantha.

To the student of geographic distribution the collection is especially timely,
since although the explorations of the recent deep-sea expeditions of the
“Valdivia,” the “Siboga,” and those of the Prince of Monaco had given us a

fairly good idea of the holoplanktonic Medusa fauna of the Tropical Atlantic

10 THE MEDUSAE

and Indian oceans, the eastern half of the Pacific still remains practically a
mare incognitum in this respect.

The collection (20 species) made in Acapulco Harbor is likewise important
from the distributional standpoint, for the Medusa fauna of the west coast of
Central America was previously almost unknown. When compared with
the West Indian Medusae it illustrates in striking fashion the close relationship
between the littoral faunae on the two sides of Central America.

Owing to the rapid growth of our knowledge of the structure and relation-
ships of the Medusae the classification of both Acraspedae and Craspedotae is
in a state of such constant change that no system as yet proposed can be ex-
pected to remain permanent. The scheme adopted in the present memoir is
based in its essentials, as all future attempts must be, on the classifications
outlined by Gegenbaur, Agassiz, and Haeckel. But I have not hesitated to
adopt the very extensive modifications which recent authors have shown to
be necessary ; and several new changes are proposed, to which attention will
be called in the appropriate connections.

Perhaps a few words are called for to explain a_ presentation of the
subject-matter in the reverse of the so-called “natural order” now usually
adopted. The present arrangement was adopted for purely practical reasons
connected with the preparation of the drawings and plates, and for the sake
of preserving a parallel arrangement of text and plates; it is not to be taken
as indicating the author’s idea of phylogeny. Within the several orders,
where supposed relationships rest on a much firmer basis than they do between
the orders, I have preserved what I believe to be the natural sequence of
families and genera.

Throughout the cruise, the care and preservation of the Medusae fell to
my special lot, so that I had the opportunity to study the great majority of the
specimens in life, or at least in the fresh condition ; a privilege of the greatest
value, as any student of this group will recognize. I was also able to prepare
colored sketches of many of the species, a few of which are reproduced in
this memoir, Colored drawings of Atolla and Ptychogena were likewise made
by Mr. A. M. Westergren, artist on the expedition.

The great majority of specimens were preserved in 5% formalin in sea
water, a method which has proved satisfactory both for gross anatomy and
for histology, its only drawback being that otoliths are frequently dis-
solved. A few individuals were preserved in alcohol, and still others in

various of the acid histologic fixing reagents. I may call attention here to

INTRODUCTION. 11

the value of chloretone as a stupefying reagent for Medusae. A few cubic
centimeters of a 1% solution of chloretone were usually added to the recep-

’

tacle in which the “ tow” was contained, and proved most satisfactory, not
only for Medusae, but also for Siphonophorae. Excellent and concise direc-
tions for the treatment of Medusae on shipboard have been published by
Browne (: 06).

In the preparation of this report I have been much assisted by having ac-
cess to the extensive collection of Medusae in the Museum of Comparative
Zoblogy, which, besides being rich in West Indian species, contains many of
the specimens from Puget Sound described by A. Agassiz (’65), as well as
those from the Fiji Islands reported upon by Agassiz and Mayer (99). The
Pacific Medusae of the U. 8. National Museum, including the Hawaiian
collection reported upon by Mayer (: 06), have likewise been at my disposal.

It is a pleasure to acknowledge my obligations to the following gentlemen
for their assistance : — to Mr. Alexander Agassiz, to whom I am indebted not
only for the opportunity to accompany the “ Albatross” on her cruise, but
for constant encouragement, advice, and criticism in the preparation of this
report; to Mr. Richard Rathbun of the U.S. National Museum for placing
at my disposal the collections of the National Museum; to Messrs. G. H. Parker,
Thomas Barbour, H. L. Clark, and O. Bryant for interesting specimens of
Medusae; to Mr. E. T. Browne, Dr. C. W. Hargitt, Dr. O. Maas, and Dr. A.
G. Mayer, for information, and counsel on knotty questions of nomenclature.

Museum or Comparative ZOOLoGyY,
CamprinGe, Mass., June, 1908.

THE MEDUSAE.

SCYPHOMEDUSAE.

Students of the Scyphomedusae are so generally agreed that Haeckel’s
(80) classification of the group is in many ways unsatisfactory, that several
attempts have been made recently to work out a more natural grouping of
the various members of the class. These have been thoroughly reviewed by
Maas (: 07), so that I need not dwell here on the historic aspect of the sub-
ject. By far the most satisfactory classification which has yet been proposed
is the result of the successive studies of Claus (’83), Vanhoffen (’92, : 02°),
and Maas (:03,:07). As provisionally outlined by the last author, (: 07,
p- 193), it is as follows: —

A. Charybdeida.

B. Three groups which together form a phylogenetic series.

1. Stauromedusae, exclusive of the Tesserida.
2. Coronata.
3. Discophora.

This scheme shows an important advance over the one proposed by
Vanhioffen (92, p. 20), in abandoning the division of the Scyphomedusae into
Cathammata and Acathammata. Such a separation of the class into two
opposed groups, based on the presence or absence of septal nodes, is prob-
ably of no phylogenetic significance, since, as Claus has shown, it is
doubtful whether the septal nodes of the Coronata and the long ‘“ Septal-
leisten” of Stauromedusae and Charybdeida are homologous, it being
altogether likely that the septae, at least of the latter group, are not
homologues of the primitive taeniolae of the scyphistoma, but are new form-
ations on the part of the endoderm. Another serious objection to his
grouping is that it results in the close association, under the heading
Acoronata, of the widely divergent Charybdeida and Stauromedusae, an
association which Vanhdffen (: 02", : 06) has himself admitted to be irrational.
Lastly, employment of the presence or absence of septal nodes as the chief
criterion results in laying too strong emphasis on the distinction between

Coronata and Discophora.

14 THE MEDUSAE.

I fully agree with Maas (: 07), indeed, I think that no actual student
of the Seyphomedusae will now dispute, that the Charybdeida are a very
aberrant group. But I think it very doubtful whether the three remaining
groups which he enumerates — Stauromedusae, Coronata, and Discophora —
do actually form a phylogenetic series as he suggests (: 07, p. 193). To
assume this seems unwise until we have a clearer idea of the affinities of the
Lucernarida, For even if we accept the view that the Lucernarida are
in reality not Medusae at all but Scyphistomata which attain sexual maturity,
and that their fixed habit is therefore a primary, not a secondary, character,
we cannot safely assume that they are necessarily ancestral forms. On the
contrary, it is entirely possible that they ought rather to be regarded as off-
shoots of one of the more highly developed groups. Furthermore, although
it will, I think, be generally admitted that the relationship between Coronata
and Discophora is closer than Vanhdffen’s separation of the Scyphomedusae
into Cathammata and Acathammata suggests, yet there is strong evidence
against regarding these groups as connected by a direct genetic relationship.
Though we may not regard the presence or absence of septal nodes as of
the first importance in classification, yet these structures are of morphologic
importance and of regular occurrence among the Coronata; and there is con-
siderable evidence, as we know from the studies of Claus (’83) on the
development of Nausithoé, for regarding them in the Coronata at least,
even if not in the Charybdeida, as partly, if not wholly, homologous with
the original taeniolae of the scyphistoma, Like so many problems in
medusology, this is a question requiring further embryologic study; but
should the septal nodes of the Coronata actually prove to represent the
taeniolae, their phylogenetic significance in classification would, of course, be
very great. At any rate, their presence in the Coronata and absence in
the Discophora suggests a parallel, rather than a serial, relationship between
the two groups.

Maas’s provisional scheme shows an apparent shortcoming in that it
provides no place for the Tesserida, since he states that the Stauromedusae
are “'Tesserida auszuschliessen” (: 07, p. 193); but in any formal classi-
fication of the Seyphomedusae some place must, of course, be found for
this group. Considering the fact that their affinities, and even many points
in their structure, are very problematical, it seems to me as well, to
retain them provisionally among the Stauromedusae. Various ideas as

to their significance have been entertained. It is by no means necessary to

CHARYBDEA. 5

suppose, with Haeckel (80), that they are primitive Scyphomedusae ; on the
contrary, there are some grounds for concluding, with Hickson (: 06), that
they really represent precocious Scyphistomata, such as the Lucernarida,
which have secondarily acquired the free swimming habit. But to come to
any sound conclusion on this point, it is absolutely necessary to have fresh
material. Further speculation based on Haeckel’s (80) description and
figures seems not only unprofitable but misleading.

For these reasons it seems best to modify the scheme proposed by Maas
(: 07), as follows, and to refrain from assigning to the various orders of the
class any serial phylogenetic relationships : —

Order 1. Charybdeida, a very aberrant group.

Order 2. Stauromedusae (Lucernarida and Tesserida).

Order 3. Coronata.

Order 4. Discophora (Saemaeostomata and Rhizostomata).

CHARYBDEIDA.
Charybdeidae Gegenbaur.
Charybdea Péron et Lesueur, 1809.

The ten species which have been described under this genus differ so
slightly one from another, and that only by characters of whose systematic
importance different opinions may reasonably be held, that it is difficult to
pass judgment on their validity. Maas ('97) has already expressed a doubt
as to whether all the species enumerated by Haeckel (’80) are really distinct,
suggesting that we may, at least in part, be dealing with geographic races,
a conclusion supported by the fact that a different species has been described
for almost every locality from which the genus has been recorded. But, on
the other hand, these races, even if they be nothing more, often seem to be
constant, as is the case for C. marsupialis from the Mediterranean; while
enough specimens of C. caymachana have now been examined by Conant (98)
and by myself to suggest that this form is also well founded.

We must bear in mind, in deciding what characters and differences are
best fitted to serve as the bases for specific distinctions, that Charybdea should
be judged from a different standpoint from Pelagia, or the trachyline
Hydromedusae. Although Charybdea and Pelagia, if viewed merely from
the descriptive standpoint, seem to show a close parallel in that in both

genera numerous closely allied species or races have been described from

16 THE MEDUSAE.

different localities, yet a study of the distribution and development of the
two genera shows that this parallel is only apparent. Pelagia is a truly
oceanic genus, in which the so-called species are probably not geographically
constant. Charybdea, on the other hand, almost certainly passes through a
scyphistoma stage (Haacke, ’87), and is usually recorded from harbors, inlets,
or, at the most, from but a few miles off-shore. Furthermore, its races seem
to be constant and are often isolated from. one another. It is very doubtful
whether such slight and geographically inconstant variations as those of
Pelagia and many such oceanic Hydromedusae as Rhopalonema, deserve
any recognition in nomenclature. But in the case of such a geographically
restricted and local genus as Charybdea equally small variations, when not
representing mere developmental differences, are of much greater systematic
importance, and, if they prove to be constant for different localities, may
well be regarded as the basis for specific distinctions. Differences due to
different stages in growth must however be carefully guarded against; it
was such a one, simple or branched condition of the velar canals, on which
Haeckel (’80) founded the subgenera Charybdella and Charybdusa.

The characters of greatest specific importance in the genus are size and
eeneral form of adults, structure of the phacelli, number of the velar canals, .
and their condition, whether branched or simple, if, indeed, simple canals
should prove to be characteristic of the adult of any species of the genus,
which at present seems doubtful.

Owing to the facts that most of the older species were founded on such
unstable characters as the relative proportions of different parts of the bell,
that many of the specific descriptions are altogether inadequate, and that
practically nothing is known of the younger stages in growth of most of the
species, it would be hopeless to attempt any revision of the genus without a
study of extensive series of specimens from the type localities of the various
forms. :

I believe that it is very important that descriptions of specimens of such
genera as Charybdea should be as detailed and specifically diagnostic as
possible, whether new or old species be in question. Neglect of this pre-
caution, particularly in the case of Pacific Medusae, and the practice which
some writers follow of giving no reasons for their specific identifications,
even when these form the bases for important generalizations, have made
the study of the geographic distribution of the Medusae much more difticult
than it need have been.

CHARYBDEA RASTONII. 17

Charybdea rastonii Haacke.

Charybdea rastonii Haacke, ’87, p. 591, taf. 35; Mayer, :06, p. 1134, pl. 1, figs. 1-1e.
? Charybdea arborifera Maas, ’97, p. 86, taf. 14, figs. 7-10.

Plate 1, Fig. 4; Plate 10, Figs. 1-7.

Three specimens, Mangareva Harbor, surface.

I have likewise had the privilege of examining the considerable series
from the Hawaiian Islands, including various stages in growth, on which
Mayer based the record noted above.

The specimens present immature characters in the structure of the
phacelli and velar canals, and agree very closely with Haacke’s (’87) de-
scription of the young of this species from near Adelaide, Australia, as well
as with Hawaiian specimens of a corresponding size. The measurements
of the present specimens are, 13 mm. in diameter by 14 mm. high; 13 mm.
in diameter by 13 mm. high; 8 mm. in diameter by 9 mm. high. In the
largest specimen, which, from the condition of the gonads, is apparently about
half grown, the bell is rather cubical, and the exumbrella shows the sculp-
ture characteristic of the genus (PI. 10, figs. 2, 3). The pedalia, which have
often been considered of systematic importance in this genus, are narrow and
ovate in all the specimens, being but slightly deeper along their inner
than along their outer sides. The stomach, as is shown in a somewhat ideal
section (Pl. 10, fig. 6), is very flat, without any trace of the mesenteries
characteristic of the allied genus Tamoya.

The canals. —In every specimen there are sixteen canals, four between
every two frenula, the two near the tentacles being larger and longer than
the two near the sense organs. In the two smaller specimens from Manga-
reva all the canals are simple, but in the largest individual one of them
shows signs of branching, thus indicating that the simple condition is merely
a temporary one, as Haacke (’87) has’ pointed out. In larger specimens,
Hawaiian, the branching is more complex, resembling Haacke’s figures of
adults.

The phacellae. —In the smallest. specimen these consist of ovoid thicken-
ings at the four corners of the stomach, each bearing from ten to fifteen
simple filaments. The largest specimen shows a much more advanced con-
dition. The filaments in each phacella (PI. 10, fig. 7) have become collected
into three or four groups, each group arising from a distinct stalk. The

filaments, furthermore, arise from the stalk at different levels, and some of
2

18 THE MEDUSAE.

them are apparently branched, so that they present a tree-like appearance.
In the largest Hawaiian specimens each phacella consists of from six to eight
groups of filaments.

The sense organs show the structure apparently universal at least among
the young of this genus, having two large single median and four small paired
lateral ocelli. But it is of course impossible to determine whether the paired
ocelli would be lost with growth, as Haacke (’87) found to be the case in his
Australian specimens.

The Mangarevan as well as the Hawaiian specimens, agree closely with
Haacke’s account of corresponding stages. Haacke (’87) and Mayer (: 06)
have described all the canals in the adult as branched, but the former author
has observed that in rather small specimens the eight canals next the sense
organs were entirely simple, while the eight next the tentacles showed only
a very faint trace of branching, a condition already attained in one quadrant
of our largest specimen. It is true that branching of the canals appears to
take place rather earlier in the Australian than in the Mangarevan specimens ;
but this slight difference, even if it prove to be constant, can hardly be con-
sidered anything more than a local peculiarity.

The phacellae also closely agree with Haacke’s account of corresponding
stages in their growth in his specimens. In the youngest which he exam-
ined they presented exactly the same condition as that which I have just
described for our smallest individual, the simple filaments of each phacella
arising in a single row from a thickening at the corner of the stomach.
The phacellae of our largest specimen resemble those of Haacke’s half-grown
individuals, while in the large Hawaiian specimens they agree with his
account of the adult stage. There are no important differences between
our specimens and those described by Haacke other than such as may be
accounted for by different stages in growth.

Since this species was first described by Haacke, the only record of its
occurrence is that given by Mayer (:06) from the Hawaiian Islands. The
identity of C. arborifera Maas, which I have classed as a probable synonym of
this species, is not altogether clear. The strong general likeness of this form,
taken at the exact locality, Honolulu Harbor, from which Mayer (: 06) has
since recorded C. rastonii, to the latter species, has already been noted by
Maas (97) himself. His specimens, however, showed two striking differ-
ences from the typical C. rastoni’: —the exumbrella was without sculpture ;

and the phacellae were dendritic, all the filaments of each arising from a single

CHARYBDEA RASTONII. 19

stalk, The lack of exumbral sculpture seems less important than Maas
supposed, since it was observed only on alcoholic specimens. Nor does
the condition of the phacellae appear to be sufficient ground for establish-
ing a new species, since the dendritic structure which he describes is not
essentially different from that of the phacellae of the half-grown Q. rastonii
in the present collection, and Maas’s specimens seem to have been at about
the same stage in development. Maas (97) also believes that the sense
organs of C. arborifera show a marked deviation from those of C. rastonii, since
paired ocelli were present in all his specimens. But we know from Haacke
that it is only in individuals of the former species more than 20 mm. in
height (’87, p. 603, two thirds grown) that the paired ocelli disappear, and
it is by no means certain that the same may not be true of C. arborifera, inas-
much as the largest specimen which Maas examined was only some 15 mm.
high. Finally, the geographic distribution of these forms offers an additional
argument against regarding C. arborifera as separate from C. rastonit, since it
seems unlikely that two distinct, yet so closely allied, species should occur
side by side in such a restricted locality as Honolulu Harbor.

For the sake of mapping out the distribution of the Medusa fauna of the
Pacific, it would be of great importance to know the true status of three
other species of Charybdea, phillipina Semper, grandis Agassiz and Mayer, and
moseri Mayer, all of which are very closely allied in so far as regards the
structure of the phacellae and the number (24) of velar canals. Mayer (: 06)
believes that his new species C’. moseri is very close to C. phillipina. But it seems
to me that this is probably an error, since the two are sharply separated by
a constant difference in size, C. phillipina having gonads when 30 mm. high,
while C. moseri shows no trace of them until some 60 mm. high. Charybdea
moseri and C’. grandis, however, show such close affinities to each other that it
may be questioned whether they are not really two stages in the growth of
one species. Maas (: 03) has, it is true, suggested that C. grandis is in reality
Tamoya, not a Charybdea. But Mayer’s figures, though not altogether con-
clusive, indicate the short flat manubrium characteristic of the latter genus.
There is no doubt of the correctness of Mayer’s contention that C. moseri is a
typical Charybdea, a contention I have myself been able to substantiate on
a considerable series of well-preserved specimens from the Hawaiian Islands.
The only important difference between C. grandis and C. moseri is that in
C. grandis the twenty-four canals are slightly branched, whereas in all the

specimens of C. moseri they are simple. But since we now know that in

20 THE MEDUSAE.

other species of Charybdea in which the canals in adults are branched, the
sane structures in the young are simple, it is altogether probable that
this difference is due merely to the difference in the stages of develop-
ment of the two series. Nor does the very slight difference in the shape
of the pedalia which Mayer has described seem of much importance, since
he studied C. grandis on fresh, C. moseri on preserved, specimens. On the
other hand, a peculiar crescentic form appears characteristic of the phacellae
of both forms; and since they so closely resemble each other in other
particulars, e. g., large size, form, and number of canals, I believe that they
represent but a single species.

I have likewise been able to examine two specimens of a very large
Charybdea from the Society Islands, in the collection of the Museum of Com-
parative Zodlogy, which also appear to belong to C. grandis. They are both
about 170 mm. high and of the same general form, with short pedalia, and
with the rhopalar niches high above the bell-margin. The phacellae, though
not in very good condition, form rather crescentic areas, each containing
many filaments, and the velar canals are branched, but unfortunately it
was impossible to count them, owing to the contracted condition of the circu-
lar muscles of the velarium.

If my view that these specimens and C. moseri both really belong to
C. grandis be correct, that species would extend from the Hawaiian Islands
on the north to the Paumotus on the south, and thus show in its distribution
a close parallel to C. rastonit.

CoRONATA.

In considering this order we may adopt the classification into families
proposed by Vanhéffen (: 02"). This scheme, it is true, is based chiefly on a
single character, that is, number of sense organs and of tentacles, and may
therefore be regarded as somewhat artificial. But this criticism is less serious
in such a structurally homogeneous group as the Coronata than it would be
in most other orders of Medusae; while, on the other hand, the scheme which
he has outlined is not only suggestive of the apparent relationships of the
various genera, but is also convenient in actual practice, besides readily
allowing of future additions. One such addition has already become neces-
sary, the formation of a new subfamily, Paraphyllininae (Maas, :03), to include
Paraphyllina (Maas, : 03) and the fossil genus Paraphyllites (Maas, : 06"), in

both of which the usual radial arrangement of the marginal organs is re-

i —— a

CORONATA. 21

versed. Another recent advance in our knowledge of the order has been the
demonstration by Maas (:03) that in Linerges, as in Nausithoé, the two
canals which enter each marginal lappet unite, thus forming a continuous
festoon canal, instead of ending blindly, as early students of the genus
supposed. This discovery, already made by Vanhiéffen (:02*) and _ since
substantiated by myself on excellent specimens of LZ. mercurius from the West
Indies and of L. aquila from the Fiji Islands, brings the vascular system of
Linerges into fundamental agreement with that of all other genera belonging
to the order.

Under the Coronata we may distinguish the following families : —

Periphyllidae, with four sense organs. Under this family are two
sub-families : —
a. Periphyllinae, with the ordinary radial arrangement.
b. Paraphyllininae, with the radial arrangement of the marginal
organs reversed.
Atorellidae, with six sense organs.
Ephyropsidae, with eight sense organs.
a. Nausithoinae, lappet-canals simple, without subumbrellar sacs.
b. Linerginae, lappet-canals branched, with subumbrellar sacs.
Atollidae,' with more than eight sense organs, and with an irregular
number of metameres.

Recently Kassianow (:01) has proposed another classification of this
group, based on unfamiliar, even if not wholly novel, grounds, which dif-
fers so essentially from the one outlined above that I cannot pass it by
without brief notice, even though Maas (:07) has already reviewed it in
detail. Kassianow gives to the condition of the marginal lappets a much
higher importance than other students of the group have usually attached to
them, and he believes that in the homologies of these structures he finds
reason to discard the otherwise homogeneous order Coronata. According to
his view the rhopalar lappets of Periphylla and the eight lappets of Pericolpa
are not homologous; nor are the eight adradial lappets of the latter the
true rhopalar lappets of that form. On the contrary, following Claus (86),
he believes that he can find evidence in Haeckel’s (’80) figures of Pericolpa
of the existence at the base of each of the four sense organs of a small,
undivided lappet. According to his theory these masked, and but slightly

1 The name Collaspidae has usually been employed for this family, but since the genus Collaspis
has been shown by Fewkes to be a synonym of Atolla I follow the International rules of zoological
nomenclature in substituting Atollidae.

22 THE MEDUSAE.

-

developed, structures are the true rhopalar lappets of Pericolpa, correspond-
ing to the rhopalar lappets of Periphylla. The large adradial lappets of
Pericolpa are, then, in reality tentacular lappets, which correspond, from
their position, to the eight adradial arms of the Lucernarida, and to what he
believes, from Haeckel’s (80) figures, to be the primitive lappets in the Cha-
rybdeida. They are not, however, homologous with the tentacular lappets
of Periphylla, but are replaced in this and all higher genera by the adradial
tentacles. The tentacular lappets in Periphylla are wholly new formations.
The relation, according to Kassianow, of Periphylla to Nausithoé is one
of direct descent, the perradial tentacles of the former being replaced by
the perradial sense organs of the latter. To this view there are, to my
mind, vital objections. To begin with, students are now very generally
agreed that the Charybdeida are an aberrant group, showing no close rela-
tionship either to the Stauromedusae or to the Coronata. In the second place,
there is strong reason to believe that his interpretation of the lappets in Peri-
colpa is erroneous. The supposed “sense lappets”’ of this genus which he be-
lieves to be shown on Haeckel’s figure are very problematic. Haeckel makes
no mention of them, and the structures which he shows might more easily be
interpreted as prolongations of the rhopalar pedalia, a view to which, as it
seems to me after examining the figures, there is no objection. Furthermore,
and of great importance, is the fact that Maas (: 03), who has recently had an
opportunity of examining specimens of this genus, makes no mention of these
lappets, although he would certainly have been on the lookout for them. It
is, then, very improbable that any such lappets exist. Even aside from this
essential objection, there are strong drawbacks to any classification based in
its essentials on the homologies of such irregular serial parts as the marginal
lappets. Indeed, his scheme can hardly include the newly discovered genera
Atorella and Periphyllopsis, which, as Maas (: 07) has pointed out, show a
numerical condition of the tentacles and lappets incompatible from any
reasonable standpoint with Kassianow’s concept of their homologies. Still
more important is the discovery by Maas (: 03, : 06") of two genera, one (Pa-
raphyllina) recent, the other (Paraphyllites) fossil, which, while closely allied
to Periphylla in every anatomical respect, show in the radial arrangement of
their marginal organs an exact reversal of the ordinary condition. This of
course indicates that the significance of the distinction between per- and
inter-radial rhopalia and tentacles is, from the standpoint of phylogeny, not

a fundamental one. I cannot better express my views of the actual impor-

PERIPHYLLIDAE. RS

tance of the supposed homologies represented in the number and arrangement
of these organs than in the words of Maas: “ Zudem darf vom moderneren
Standpunkt aus geltend gemacht werden, dass auch die theoretischen Voraus-
setzungen fiir solche spitzfindige phylogenetische Ableitungen keineswegs
geniigend gesichert erscheinen, sondern dass sprunghafte Verinderungen
und Vermehrungen solcher adventiven Randgebilde auch auf anderer Basis,
nach Gesetzen der Variation und Mutation moglich sind” (: 07, p. 195).

Periphyllidae Haeckel, 1880.
sens. em. Vanhdoffen (: 02°).

This family, according to Vanhoffen (: 02%), includes all Coronata with four
sense organs, the generic distinctions within the family being based on the
number of tentacles, which, so far as known, always occur in multiples of four.
Maas (:03, :07), however, has retained Haeckel’s family Pericolpidae to
include Pericolpa, with only four tentacles. But if, as Maas himself agrees,
Periphylla with 3 X 4 and Periphyllopsis with 5 x 4 tentacles both belong to
the Periphyllidae, it seems to me irrational to separate from this family Peri-
colpa with 1 X 4 tentacles, inasmuch as in the number of tentacles this genus
bears to Periphylla precisely the same relation that the latter genus bears to
Periphyllopsis. With regard to Nauphantopsis Fewkes (86), which Van-
héffen (: 02") includes in this family on the supposition that it has four
sense organs and 7 X 4 tentacles, it is impossible to reach any decision with-
out studying fresh material, since Fewkes was unable to count definitely the
number of sense organs.

In the typical members of the family the four sense organs are interradial,
the four tentacles, or groups of tentacles, as the case may be, being perradial.
In the recently described Paraphyllina (Maas, :03), however, and in the fossil
genus Paraphyllites (Maas, : 06*) this radial arrangement is reversed, the sense
organs being perradial, and the central one of each of the four groups of
tentacles interradial. Their closest relationship is with Periphylla; they
must be regarded, I believe, as offshoots of that genus.

It appears that Periphylla may be derived from Pericolpa by the devel-
opment, in each quadrant of the margin, of a new adradial tentacle on either
side of the primitive perradial tentacle; and arguing from this conclusion it
is reasonable to assume that Periphyllopsis in the same manner is derived
from Periphylla by the development of a new tentacle on either side of each
tentacle group of the latter genus. Whether or not this has actually been

24 THE MEDUSAE.

the line of development of these three genera is impossible to determine
without studying their young stages. But the evidence afforded by the
adults suggests that such is the case.

Periphylla Steenstrup, 1837.
sens. em. Vanhoffen (: 02%).

Periphyllinae with 5 X 4 tentacles.

The anatomical and histological structure of this, the best-known genus
of the family, has been so carefully studied, since Haeckel’s (’80) description,
by Maas (97, :03,: 04°) and Vanhéffen (792, : 02°), on satisfactory material,
that repetition here is unnecessary.

The species described by Haeckel (80) under the genera Peripalma and
Periphylla, and by Fewkes as P. humilis, have been successively reduced,
until Vanhéffen (:02*) and Maas (: 04°) recognize only three: P. dodeca-
bostrycha Brandt, ’38, P. hyacinthina Steenstrup, °37, and P. regina Haeckel,
"80. The considerable number of specimens taken on the expedition of the
“Valdivia” and those of the Prince of Monaco have afforded ample opportu-
nity to these two students to make careful comparisons between these three
species. Mayer (:06), on the other hand, argues that 2. dodecabostrycha
and P. hyacinthina are in reality synonymous, the differences in form of the
bell and in extent of pigmentation being, according to his view, the result
merely of different stages in growth, or of individual variation. This view
has much to recommend it; and although I realize that further studies on
more extensive series of the two forms must be made before any final con-
clusion can be reached, I think it wisest to accept it provisionally, even
though it be sharply opposed to the opinions of two such eminent authorities
as Maas and Vanhéffen. In support of the thesis that the two species are
identical I may cite the following important observations on the part of pre-
vious students. So far as I can learn, no specimen of P. hyacinthina, showing
the characteristic form and pigmentation, has been recorded smaller than 35
mm. high, or than 21 mm. in diameter. On the other hand, we know, from
recent studies at least, of no specimen of P. dodecabostrycha larger than 27 mm. —
high, or than 18 mm. in diameter. Furthermore, no ¢ypical specimen of

P. hyacinthina has been observed without well-developed gonads, although such

specimens have been recorded several times for P. dodecabostrycha. Considering
how many individuals of the two so-called species have been examined, this

fact alone argues very strongly in favor of their identity.

PERIPHYLLA. 25

Both Vanhoffen (:02*) and Maas (: 03, : 04°) have agreed that the two
forms are characterised as follows: — in P. dodecabostrycha the bell is low and
only the central portion of the gastrovascular system is pigmented, so that the
gonads are visible from without. In P. hyacinthina the bell is high and the
distal portions of the canals are so heavily pigmented as to conceal the gonads.
As to the first of these distinctions, the evidence seems to be by no means
convincing, although there is no doubt that specimens described as P. hyacin-
thin do average rather higher than P. dodecabostrycha. Vanhiffen (: 02%, p. 23)
has given the following proportions of height to diameter for the two species :—
for P. hyacintlina 44 : 23, 39: 26, 35: 21, for P. dodecabostrycha 27:18, 12:10,
20:13. These figures as they stand are misleading, since they suggest too
great a diversity in the case of the larger (P. Ayacinthina) measurements. By
reducing them to a common standard, 7. e. in terms of the diameters, we can
form a better judgment of their true meaning. We then find the proportions
of P. hyacinthina to be 1.9:1, 1.7: 1, 1.5: 1, and of P. dodecabostrycha 1.55: 1,
1.5:1,1.2:1. It is clear, then, from these figures, to which, as I have found,
more might be added without changing their import, that in this character
there is no discontinuity between the two; indeed, one specimen of P.
dodecabostrycha is rather higher in proportion to its diameter than one of P.
hyacinthina. This character seems to be subject to considerable individual
variation. Certainly when it is analyzed it forms no basis for any safe specific
distinction, and all we can safely say is that large individuals are as a rule
rather higher than small ones. The form of the bell is probably no more im-
portant in this connection, for Maas (: 04°, p. 47) has already recorded a typical
specimen of P. hyacinthina of which he says, “ ombrelle dans sa mésoglée pas
ci pointue que cela est dessiné généralement pour hyacinthina.”

The extent of the endodermic pigmentation does not seem much more
valuable as a specific criterion, for not only is this character variable among
Medusae in general, but also there is evidence that in Periphylla the
amount of pigmentation increases with growth. Thus while in two very
small specimens in the present collection the pigment is entirely restricted to
the central stomach, not even the ring sinus showing any trace of color, in
five somewhat larger specimens from the Gulf Stream, and four, all about 20
mm. in height, from off the Alaskan coast, as well as in most described
specimens of P. dodecabostrycha, the ring sinus is somewhat pigmented, though
not enough to hide the gonads; and in all large specimens of the genus yet

recorded, at least by recent authors (except those referable to P. regina) the

26 THE MEDUSAE.

entire endodermal system is described as densely pigmented. The fact that
the two forms, P. dodecabostrycha and P. hyacinthina, have both often been taken
not only at the same locality, but even in the same haul, is a further, even
if indirect, argument in favor of the view that they represent nothing more
than different stages in the growth of but one species. If this be the case,
the older name, P. hyacinthina Steenstrup, ’37, must be retained.

As to the validity of P. regina Haeckel, which both Maas (’97, : 04°) and
Vanhiffen (: 02) retain as a good species, I am not able to form any final
opinion, since I have at hand only a single rather fragmentary alcoholic
specimen from the Gulf Stream, which can be referred to this species. The
fact, however, that in this form the gonads do not appear until a size of
some 70 mm. in diameter is attained (Vanhiffen, :02*) argues strongly for
the view that it is a distinct species. There appears, also, to be a definite
difference in its color from that of the other species, although this difference
is not shown in Vanhiffen’s figure.

Periphylla hyacinthina Steenstrup.

Periphylla hyacinthina Steenstrup, 37; Haeckel, ’80, p. 419; Vanhéffen, :02%, p. 28,
taf. 2, fig. 9; Maas, : 04¢, p. 47, pl. 5, fig. 38, pl. 6, figs. 45, 46.

? Charybdea bicolor Quoy et Gaimard, 733, p. 293, pl. 25, figs. 7-3.

Quoyia bicolor L. Agassiz, ’62, p. 173.

Charybdea periphylla Péron et Lesueur, : 09, p. 332; Blainville, ’34, p. 275, pl. 31, fig. 7;
L. Agassiz, ’62, p. 173.

Periphylla peronii Haeckel, ’80, p. 420.

If we accept the view that P. hyacinthina and P. dodecabostrycha are in

reality but one species, the following synonyms must also be included : —
? Chrysaora (dodecabostrycha ?) dubia Brandt, 738, p- 387, taf. 29, 30.
Dodecabostrycha dubia L. Agassiz, ’62, p. 173.
Cassiopia dubia Lesson, 43, p. 408.
Periphylla dodecabostrycha Haeckel, ’80, p. 421; Vanhdffen, ’92, p. 10, taf. 2, fig. 2; : 02,

p. 23; Maas, ’97, p. 63, taf. 9; : 045 p. 47, pl. 5, figs. 36, $7.

Plate 1, Fig. 3; Plate 9, Fig. 2.

Station 4652; 200 fathoms to surface; one specimen, very fragmentary,
15-20 mm. in diameter.

Station 4669; 3800 fathoms to surface ; two specimens; diameter about
10 mm.; fair condition.

Station 4707; 300 fathoms to surface ; one specimen, 80 mm. in diameter
by 90 mm. high.

Also twenty-three other specimens ranging from 20 mm. to 40 mm. in

PERIPHYLLOPSIS. yar

height previously collected by the “ Albatross” in the Pacifie, including
those recorded by Mayer (:06) from the Hawaiian Islands.

The only large Periphylla taken during the expedition was alive, and
swam vigorously by pulsations of the bell when placed in an aquarium jar.
So far as the pigmentation is concerned, it is a typical P. hyacinthina, the pe-
ripheral canal system being so densely pigmented that no trace of the gonads
can be seen from without. In outline, however, it more nearly resembles P.
dodecabostrycha, the proportion of height to diameter being only about 1.1: 1.
Moreover, the bell is much less pointed than Vanhéffen (: 02%, taf. 2, fig. 9)
has represented it, a condition already noted by Maas (: 04°, p. 47) fora
specimen collected by the Prince of Monaco. After watching the alternate
contractions and expansions of the living specimen, I feel sure that small
differences in the form of the bell are to be regarded merely as due to different
degrees of contraction. As has often been described for the species, the
present specimen shows an apical projection of the stomach into the meso-
gloea. But that the presence of this structure is good evidence that Peri-
phylla passes through an attached scyphistoma stage seems to me very
doubtful. The general color, which is that characteristic of the genus, is
very well represented in Vanhdffen’s figure.

The three small specimens from Stations 4652 and 4669 would be referred
to P. dodecabostrycha if the latter were recognized as a separate species from
P. hyacinthina. The measurements of the two better-preserved specimens
are about 4 mm. high by 8 mm. in diameter, both being somewhat flattened.
None of them show any trace of gonads. They are in all respects typical
P. dodecabostrycha, having the low bell and the endodermal pigment wholly
restricted to the central stomach, as is characteristic of that form.

I have reproduced, in Pl. 9, fig. 2, a colored sketch made from the
fresh specimen to illustrate more fully this limited pigmentation. — It is
interesting to observe that although the peripheral canal system is entirely
hyaline, the rhopalia are pigmented. The ring muscle is already well
developed, as are the pedalia, and the ring furrow is deeply marked.
Unfortunately all three are too much battered to determine whether a “ Stiel-

canal” was present, a question of great interest in such small specimens.

Periphyllopsis Vanhdéffen, 1902.
Periphyllinae with four sense organs, 5 X 4 tentacles and 6 X 4 marginal

lappets.

28 THE MEDUSAE.

This genus was founded by Vanhiffen (: 02°, p. 27) for a new Medusa taken
by the “Valdivia” in the Indian Ocean. Unfortunately the single speci-
men was so fragmentary that although it showed the most important generic
character, i. e. the number of marginal organs, and its close structural affin-
ity to Periphylla, it did not allow of any detailed description. Undoubtedly
belonging to this same genus is a specimen in the present collection which
is in sufficiently good condition for me to add considerable to Vanhéffen’s
account. It is impossible to be confident of the specific relationship of the
“ Valdivia” to the “ Albatross” specimen, because of the poor condition of
the former; yet, since the few differences between the two can easily be
explained as due to differences in preservation, I identify the present speci-

men as Vanhiffen’s species.

Periphyllopsis braueri Vanhéffen.
Periphyllopsis braueri Vanhdffen, : 02, p. 27, taf. 2, fig. 7.
Plate 9, Fig. 1; Plate 12, Fig. 7.

Station 4652; 400 fathoms to surface ; one specimen, 60 mm. in diameter
by 25 mm. high.

The single specimen is fairly well preserved, but a large part of the
stomach and several of the marginal lappets are torn away, while all of the
sense organs are battered.

The bell is flattened, so that at first glance the specimen, like the “ Val-
divia” example, resembles an Atolla rather than a Periphylla. But in the
present case this condition is apparently normal, instead of being the result
of imperfect preservation, as Vanhiffen believed. The ring furrow is deep,
the pedalia are prominent, and all, both tentacular and rhopalar, of the same
breadth. The central disc is about 50 mm. in diameter, its gelatinous sub-
stance thick, and its exumbrellar surface smooth. As stated above, there are
twenty tentacles, arranged in four groups of five each, each group alternating
with a rhopalium, Alternating with rhopalia and tentacles are twenty-four
ovate marginal lappets. The radial arrangement of the different series of
organs is the same as in Periphylla, each rhopalium lying in the radius of
the centre of one of the sides of the stomach, being thus interradial, while
the central one of each group of five tentacles is perradial, lying in the
radius of one of the gastric ostia (Pl. 21, fig. 1).

The tentacles are about as long as the bell-diameter, and taper gradually
from base to tip (Pl. 9, fig. 7). The sense organs are all so much damaged

that I can give no description of their structure.

PERIPHYLLOPSIS BRAUERI. 29

~

The ring muscle, though distinguishable, is very weak, as in Atorella, a
condition apparently normal, since it shows no sign of injury, but presents a
very uniform condition throughout its entire course. This structure was
not distinguished in the “ Valdivia” specimen.

The distal portion of the stomach is much battered, but both its basal part
and the entire peripheral canal system are intact. In its basal outline the
stomach resembles Atolla rather than Periphylla. The four septal nodes
forming its sides (PI. 12, fig. 7) extend so far centrally that they nearly
divide the floor of the stomach into as many petal-like compartments. The
gastric cirri, between eighty and one hundred in number, are arranged in
continuous series as is shown on Pl. 12, fig. 7. The peripheral canal
system, shown in Pl. 12, fig. 7, corresponds closely to that of Periphylla,
and is typical of the family. The ring sinus is about 10 mm. broad.
Twenty-four broad radial canals, one in the radius of each rhopalium and
of each tentacle extend outward from it (PI. 12, fig. 1, er., ct.). Each
canal divides at the base of its corresponding rhopalium or tentacle, one
branch running into the lappet on either side, and there uniting with the
branch of the neighboring canal, thus forming a continuous festoon canal.
In two instances the septum between two adjacent radial canals is partially
subdivided by a short blind canal arising from the ring sinus. The occur-
rence of these structures does not, in my opinion, point to a future formation
of new tentacles, since the structure of the gonads shows clearly that the
specimen was senescent ; but probably indicates merely sporadic local de-
lamination of the essentially double vascular endoderm layer in the septal
regions.

The distal part of the stomach, though much torn, was evidently of con-
siderable length, with thick, stiff walls. The lips are entirely destroyed.

The gonads are empty, but their positions and form are clearly visible,
and their covering layers of tissue are intact, a fact suggesting that their
emptiness is due to the natural discharge of their contents. They are oval
in outline, eight in number as in all Periphyllidae, and equidistant one from
another (PI. 12, fig. 7).

The color of the species, as it appeared in the fresh specimen, is rep-
resented on Pl. 9, fig. 1. The entire endodermal system is pigmented,
the stomach densely and the peripheral canals more faintly, with the deep
chocolate-red color so characteristic of the Medusae of the intermediate

depths.

30 THE MEDUSAE.

Atorellidae Vanhoffen.

This family, founded by Vanhiffen (: 02°, p. 51) for the new genus
Atorella with six rhopalia and six tentacles, occupies an obscure _posi-
tion among the Coronata. Not only is the number of marginal organs
unusual, but the fact that there are only four gonads, and these, as we
shall see (p. 32) without any anatomical evidence of a double nature, is
remarkable. The number of tentacles and sense organs may readily be
derived, either through duplication, a process which has apparently played
an important part in the phylogeny of the different genera of the Periphyl-
lidae, or by reduction. But the condition of the gonads is less easy to account
for. So far as we know, eight is the primitive number of these organs in
every other genus of the order; and although in certain forms, e. g. Palephyra,
pairs of adjacent gonads may become secondarily apposed, or even partially
united, yet such pairs always show evidence of their double origin. Whether
we are to regard the gonads in Atorella as a further step in such a process
of fusion, or as the primitive condition for this form, must remain problem-

atic until their development can be studied.

Atorella Vanhoffen, 1902.

Atorellidae with 1 X 6 tentacles and with only four gonads.

The single specimen for which Vanhiéffen (: 02") founded the genus was
exceedingly fragmentary, allowing of little more than a determination of
the number of tentacles and of rhopalia. More recently Maas (: 03, p. 10) has
described, from the collections of the “ Siboga,” a second specimen in a better
state of preservation, which he has identified as Vanhiffen’s A. subglobosa.
Three specimens in the present collection undoubtedly belong to this same
genus, but differ so markedly from the “ Siboga” specimen in the sculpture
of the exumbrella, structure of the tentacles, and general form, that I

believe they belong to a distinct species.

Atorella vanhoffeni, sp. nov.
Plate 1, Fig. 2 Type; Plate 11, Figs. 1-8 ; Plate 12, Figs. 2-4.
Station 4619, surface. Three specimens, one in excellent, the other two
in fair, condition. ‘Their dimensions are: —two 5 mm. high and 6 mm. in
diameter, the third more flattened, 3 mm. high and 7 mm. in diameter. In
all three the ring furrow is deeply marked (PI. 11, fig. 2). In A. subglobosa

both Vanhéffen and Maas deseribe the exumbrellar surface as smooth. In

ATORELLA VANHOFFENI. 31

the present species, however, it is set with numerous very prominent nettle
warts, the whole bell looking much like a small Pelagia (PI. 1, fig. 2;
Pl. 11, figs. 17-3). These warts are not confined to the central disc, but
extend over the marginal region and lappets as well. They are merely
rounded eminences ; it is not likely that their outline will prove of specific
importance. Structurally they consist of closely crowded ectoderm cells
among which lie nematocysts (Pl. 11, fig. 3 n.).

The marginal lappets are oval, and very much longer than Maas repre-
sents them (: 03, taf. 3, fig. 16); but since he states that in the “ Siboga”
specimen they were damaged, it is doubtful how closely the outlines in his
figure represent the natural condition. In the number of lappets, likewise,
the condition of his specimen was probably misleading, since he figures
twenty-four, two alternating with every tentacle and sense organ. Van-
hiffen, however, figures (: 02%, taf. 3, fig. 71) the original specimen of the
genus with one lappet between each tentacle and sense organ, as is the case
in the present specimens, and this condition is, I believe, normal for the genus.

The tentacles are about as long as the diameter of the bell. In A. subglobosa
Maas figures them as simply tapering; in the present species, however, each
tentacle bears at its tip a knob-like swelling (PI.1, fig. 2). In longitudinal section
it is seen (PI. 11, fig. 5) that this swelling involves both cell layers and that
the ectoderm contains many nematocysts. Similar, though less pronounced,
nematocyst swellings may also occur at other regions along the tentacles.

The sense organs very closely resemble those of Atolla, in which genus
their structure has been so carefully worked out by Vanhdffen (: 02") that

repetition here is unnecessary

Their general form is shown in PI. 11,
figs. 6, 7, and a somewhat diagrammatic longitudinal section in PI. 11, fig. 8.
The octocyst and ventral bulbus, as well as the covering scale, are large and
prominent, but there are no ocelli, as already noted by Maas (: 03), who also
notes the resemblance to the rhopalia of Nausithoé. In finer structure
there is one important difference from the condition in Atolla. In the
latter, as figured by Vanhiffen (: 02°, taf. 7, fig. 57) the exumbral surface of
the scale is covered with ordinary ectoderm, while in Atorella, in the same
region, the cells are so closely crowded as to form a well-defined thickening ;
but whether this is sensory in function is doubtful.

The stomach is shallow and flattened (PI. 12, fig. 4), the mouth parts short,
and the mouth opening with a slightly thickened lip. The four septal nodes

(Pl. 12, fig. 4 ca) are narrow, the intervening ostia (os) correspondingly broad.

32, THE MEDUSAE.

The gastric cirri present a somewhat different condition from that figured
by Maas (: 03, taf. 3, fig. 276). They are arranged in four groups, each
group arising from a single stout stalk (PI. 11, fig. 4). There are in all from
eighty to one hundred filaments.

The peripheral canal system was easily demonstrated in one specimen by
injection with carmine. In general, as is shown in Pl. 12, fig. 4, it
resembles the type of Periphylla, there being twelve broad radial canals, six
rhopalar and six tentacular, separated one from another by narrow septal
regions. At the bases of the marginal organs the canals divide, the branches
of adjacent canals uniting in the marginal lappet to form a festoon canal.

The specimens are especially valuable for the light which they throw on
the structure of the gonads. These, four in number, are apparently double
structures (Pl. 12, fig. 2). Such a double appearance has already been noted
both by Vanhoffen (: 02*) and Maas (: 03); but while Vanhéffen believes that
they are actually paired structures (: 02°, p. 30), Maas doubts if this is the
case, though he could not determine whether the lighter zone in the middle
of each was the line of division between two of a pair of gonads, or was the
region where the genital products are released. To settle this point defi-
nitely I prepared a series of cross sections of one of the gonads of a male
individual, from which it was at once evident that the gonad (Pl. 12, fig. 3)
is a single leaf-like structure, so folded as to leave a deep groove along its
middle line, on the inner surface. It is this groove, extending throughout
the entire length of the gonad, which forms an apparent line of separation.
Furthermore, there is but a single line of attachment for each gonad. The
gonads of a female individual are filled with a comparatively small number
of large eggs (PI. 11, figs. 1,2) so that the double appearance is not so evident.
The specimens are so perfect that there is no doubt that four is the normal
number of gonads, as Maas (:03) has stated, not six, as Vanhoffen (:02*) believed.

The ring muscle is very weak, indeed hardly distinguishable as such,
much as in Periphyllopsis. Subumbral plates, such as have been described
for Nausithoé (Maas, :03, p. 20) are, on the contrary, very prominent, par-
ticularly at the bases of the tentacles (Pl. 11, fig. 3).

The gonads are orange-yellow ; otherwise the specimens are entirely
colorless.

A. vanhiffeni is no doubt a surface species, and it is possible that the
sume is true of A. subglobosa, since both captures of the latter were made
with open nets.

NAUSITHOE. 33

Ephyropsidae Claus.
sens. em. Vanhoffen (:92).
The only members of this family taken during the expedition belong to
the subfamily Nausithoinae and to the genus Nausithoé.

Nausithoé Kélliker, 1853.
sens. em. Vanhoffen (: 024) ; Maas (: 03, : 04°).

Nausithoidae with round gonads; the eight gonads separate and equally
spaced.

The condition of the peripheral canal system of this genus has been the
subject of much confusion. Haeckel (’80) describes the “ Lappentaschen”
as ending blindly in the marginal lappets, the rhopalar canals alone dividing
and sending branches into the lappets. Claus (’83), however, showed that
this was erroneous, and by his studies, as well as those of Vanhiffen
(92, : 02?) and Maas (: 03), it has been conclusively shown that the system
as a whole follows essentially the same plan in Nausithoé that it does in the
Periphyllidae. Other structures which have been obscure are the pedalia
and ring furrow. But Vanhoffen (92, : 02*) and Maas (: 03) have recently
shown that these, though hardly to be distinguished in immature specimens,
are progressively developed with age.

The history of this genus is an interesting example of the series of
changes through which so many medusan genera and species have passed.
It was founded for certain specimens, not altogether mature, from the Medi-
terranean, named JV. punctata (Kolliker, 53). Larger specimens from the At-
lantic were set apart as a different species, VV. marginata (Kolliker,’53). Others,
differing slightly in form and color, were described by Gegenbaur (56) as
still another species, V. albida. Finally, when at last large mature in-
dividuals did come to light, they were made the basis of a new genus,
Nauphanta (Haeckel, ’80). Under this new genus, four species, V. challengeri,
NV. polaris, N. vettoris pisani, and N. albatrossi, have been described by Haeckel
(80), Fewkes (’88*), Vanhiffen (’92), and Maas (’97); while still a third genus,
Ephyroides, was instituted by Fewkes (’86). Within more recent years, as
more and more specimens have been gathered from different localities by the
various deep-sea exploring expeditions, the different species were successively
reduced, and the three genera reunited, by Vanhiffen (’92, : 02°). Mean-

while a distinct geographic color race of the original NV. punetata, not pre-

o

34 THE MEDUSAE.

viously observed, has been recorded by Agassiz and Mayer (’99, : 02) and by
Bigelow (:04), while two new and easily distinguished species of the genus,
NV. picta Agassiz and Mayer (: 02) and NV. rubra Vanhiffen (: 02+), the first a
surface, the second an intermediate form, have been discovered.

According to Vanhiffen (: 02°) five species of Nausithoé are to be distin-
guished : — WV. punctata Kolliker (’53), NV. clausi Vanhiften (92), WV. challengeri
Haeckel (’80), V. albatrossi Maas (’97), and NV. rubra Vanhiffen (: 027). To
these must be added WN. picta Agassiz and Mayer (:02); while I agree with
Maas (: 03) that the status of V. clavsi is doubtful, my own conclusion on
this point being that Vanhiffen’s single specimen of JV. clausi was certainly
immature and of which JV. picta is probably the adult.

The status of WV. challengeri Haeckel (80), is also doubtful. The only
feature distinguishing the two specimens of this species from specimens of
NV. punctaia of equal size (12 mm. in diameter) seems to be the occurrence in
NV. challengeri of slight radial furrows at the margin of the central disc. In
all other respects the figures represent typical V. punctata of large size and
with well-marked pedalia and ring furrow. Vanhoffen (: 02*) and Maas (: 03)
both consider the sculpture of the central disc a good specific character, but
it seems to me, on the contrary, that it is by no means a certain one in the
case of alcoholic specimens. This question cannot be settled without an
examination of fresh material of 1. challengert, but I am of the opinion that
the latter name will probably prove to be a synonym either of JV. punctata or
of N. pieta. N.albatrossi Maas seems to be a good species ; it is distinguished
from all other species of the genus not only by its very much greater size
(40 mm. in diameter), but also by a different arrangement of the gastric cirri,
which, as is shown in a figure from life (Maas, ’97, pl. 14, fig. 2), are asso-
ciated in bundles. V. picta, likewise, is considered by Maas (: 03), who has
examined typical specimens, a good species. Although showing no ana-
tomical features to separate it from other members of the genus, it seems
easily distinguished by its size and by a very characteristic pigmentation
of the gonads. There are, then, probably only four distinct species of
Nausithoé, which may be briefly diagnosed as follows : —

N. punelata Kolliker ; small (12 mm. in diameter), endodermal system color-
less ; gonads yellow or brown, Gastric cirri simple. Found in all oceans.

N. picta Agassiz and Mayer; with large, brilliantly pigmented gonads,
red or brown, with very short and broad tentacles; simple gastric cirri;

larger than N. punctata (22 mm. in diameter).

NAUSITHOE PUNCTATA. 30

N. rubra Vanhoffen. Entire endodermal system pigmented, of red color.
Simple gastric cirri.
N. albatrossi Maas. Very large (30-40 mm. in diameter). Gastric cirri

arranged in bundles.

Nausithoe punctata Kolliker.

Nausithoé punctata Kolliker, ’53, p. 323; Haeckel, ’80, p. 486; Claus, 85, p. 24, taf. 6-8;
Vanhotfen, ’92, p. 13, taf. 3, figs. 8, 9, :02%, p. 29; Maas, : 04°, p. 54.

Wausithoé punctata var. pacifica Agassiz and Mayer, ’99, p. 170; : 02, p. 155, pl. 7, fig. 32.

Nausithoé marginata Kolliker, ’53, p. 323.

Nausithoé albida Gegenbaur, 756, p. 211.

Ephyropsis species Gegenbaur, 753, p. 494.

Nauphanta polaris Fewkes, ’88*, p. 40, pl. 1, figs. 7, 2.

Nauphanta vettoris pisani Vanhdffen, ’92, p. 15, taf. 3, fig. 10.

Ephyroides rotaformis Fewkes, 86, p. 949, pl. 7, figs. 1, 2.

? Nauphanta challengeri Haeckel, ’80, p. 487.

Plate 12, Fig. 5.

Station 4588 ; surface ; 12 specimens.

Station 4696 ; surface ; 1 specimen.

It would seem that in the region explored by the “ Albatross” this species
comes to maturity in late autumn and early winter, for the latest capture
was on December 23, and all the specimens were large and with ripe
gonads. In all the ring furrow and pedalia are strongly marked, a condition
which appears to be usual in large specimens of this species. None of the
specimens show any trace of the brown pigment spots on the exumbrella,
which are so characteristic of the Atlantic representatives of the species,
but inasmuch as it is doubtful whether this pigmentation is universal in
the case of Atlantic specimens, although it is certainly very usual, and since
slight color differences are seldom of much systematic significance among
Medusae, it seems best, as I have already concluded for specimens from the
Indian Ocean (Bigelow, : 04), to include Pacific as well as Atlantic forms
under the one name, WV. punctata. At the same time, however, it is important
to recognize that there do occur these two comparatively constant and well-
marked geographic races.

The differences of outline, degree of development of ring furrow, and
pedalia, and the like, which have been supposed to separate Mediterranean
from Atlantic specimens, and to distinguish the species of Nauphanta from those
of Nausithoé, are, as Vanhiffen (’92, : 02") has shown, merely evidences of

different stages in growth, and bear no relation to geographic occurrence.

36 THE MEDUSAE,

Nausithoé punctata is one of the most, if not the most, widely distri-
buted of surface Medusae. Unlike most other species it does not seem
to be limited by temperature, but has been found in the far north (Fewkes,
’88*, Vanhoffen, : 02°) as well as in various parts of the temperate and tropical
Atlantic, Indian, and Pacific oceans.

Nausithoé rubra Vanhoffen.
Nausithoé rubra Vanhoffen, : 02%, p. 30, taf. 1, figs. 4, 5.

Plate 12, Fig. 6.

Station 4655; 500 fathoms to surface; 1 specimen; 15 mm. in diameter.

Station 4653 ; 300 fathoms to surface ; 1 specimen; 10 mm. in diameter.

Station 4672; 400 fathoms to surface; 1 specimen; 18 mm. in diameter.

Unfortunately all three specimens of this interesting species were in a
fragmentary condition, but still Iam able to add somewhat to Vanhéffen’s
(:02*) brief description. The bell is arched, a specimen 15 mm. in diameter
being 9 mm. high; the ring furrow well marked, and the pedalia prominent
(Vanhoffen, : 02%, p. 30). The marginal lappets, as Vanhéffen remarks, are
narrow and pointed, though, in view of the condition of the material it may
be questioned whether this is a constant character.

The structure of the sense organs in this species is of great interest, since
it is no doubt an intermediate and not a surface form. In NV. punctata, as is
well known, each sense organ bears on the ventral bulbus an ocellus with
well-developed lens. In WV. rubra, however, I was able to make certain
that on several well-preserved rhopalia there is no such structure. Each
sense organ, on the contrary, consists (Pl. 12, fig. 6) merely of otocyst,
covering scale, and ventral bulbus; and the latter, though somewhat pig-
mented, shows no more trace of any definite light-perceptive organ than is
to be found in Periphylla. This adaptation to a deep-water existence is even ©
more significant than the characteristic pigmentation of the species, to
which Vanhdéffen (: 02°, p- 30) has already called attention.

The four septal nodes are broadly triangular, and so long that the gastric
ostia are narrow. The gastric cirri are rather more numerous than in NV.
punctata, there being about one hundred in all. They are simple, and
arranged in single and continuous series along the four sides of the stomach.
Owing to the dense pigmentation of the entire endoderm, the peripheral
canal system is much more easy to follow than it is in WV. punctata, with

which it agrees in all essentials. At the bases of the marginal organs the

ATOLLA. 37

sixteen canals branch, the branches of adjacent canals uniting in the mar-
ginal lappets. Thus there are, as Maas (: 03, p. 19) has shown for NV. picta,
two canals running into each marginal lappet. The radial septa extend
inward about as far as the ring furrow, where the canals become continuous,
to form the ring sinus. This arrangement of canals is in no way different
from the canal system of the Periphyllidae. Unfortunately both the distal
portion of the stomach and the gonads were destroyed in all three specimens.
The color of the entire gastro-vascular system of N. rubra is a deep amber
red. The jelly is pale yellowish. Vanhiffen has reproduced (: 02%, taf. 1,
figs. 4, 5) two excellent figures of this species from sketches made from the
fresh specimens.

Atollidae.
The only representatives of this family yet known belong to the genus
Atolla, Haeckel’s genus Collaspis having been shown by Fewkes to be a
synonym.

Atolla Haeckel, 1880.
sens. em. Fewkes, ’86; Vanhdoffen, : 02"; Maas, ’97, : 03.

Coronata with a large and variable number of antimeres; the tentacles
inserted much higher on the exumbrella than are the rhopalia,

Our knowledge of this genus since its discovery by Haeckel (’80) has
been gained only step by step. And although, thanks to the studies
of Maas (97, : 03, : 04°) and Vanhéffen (: 02*), the general anatomy and the
more important features in the histology of the genus have now been thor-
oughly worked out, the systematic relationships and specific characters of
its members are still by no means clear. The most important contribution
to this subject is that of Vanhdéffen (: 02"), who was able to study a larger
series of fresh specimens from the collections of the “ Valdivia” than ‘any
other student has had access to. His conclusion, accepted in the main by
Maas (: 03,: 04°), is that neither proportions of different parts, nor the num-
ber of antimeres is of any specific importance, but that the characters
which form the best bases for separating species are the presence or lack of
radial furrows on the central disc, and their number and form if present ; the
presence or lack of exumbral nettle warts ; and the size of the septal nodes.
The presence or absence of radial furrows appears, not only from Vanhiéffen’s
studies but those of Fewkes, (’89"), Maas, (: 04°), Mayer (: 06), and from the

present collection, to be an exceedingly stable character. It is true that

38 THE MEDUSAE.

with growth the furrows become confined to the margin of the dise ; but in
species in which they occur they are still distinguishable even in the largest
specimens. Whether the number of the furrows can be regarded as of
specific importance is doubtful. All recent authors agree that when furrows
are present they are one less in number than the tentacles. Haeckel (’80),
however, described Collaspis achillis as having twice as many furrows as
tentacles. But considering the “ suspicious circumstances ” (Fewkes, 89%, p.
531) under which this species was described, it is best, I think, not to lay any
stress on this character. The difference in form of the furrows, whether nar-
row or broad, the basis for the distinction of A. verrilii from A. wyvillei, is, ac-
cording to Vanhiffen, a constant one; but, as we shall see, specimens in the
present collection present conditions which throw doubt on this conclusion. |
Therefore it is best to reserve final judgment on this point until larger
series have been studied.

Maas (: 03, : 04°) has described a hitherto unnoticed character in specimens
of A. valdiviae and A. bairdi’,i. e. the presence of septal areas subdividing the
tentacular canals near their bases, the presence or absence of which may
prove, when more fully known, to be a specific character of great impor-
tance. Ground for this belief is afforded by the fact that these structures
are lacking in A. wyvillei,as well as in specimens from the Hawaiian Islands
described by Mayer (: 06) under the name A. alexandri.

Whether the species which Vanhiffen and Maas recognize are all dis-
tinct, or whether such differences between them as the different sizes of the
septal nodes of A. bairdi and A. valdiviae are not, at least in part, due to dif-
ferent stages in growth or to individual variation seems to me very doubtful.
But it is hopeless to attempt any revision without large series of the
different forms. The following species seem to be the best founded, and
may be characterized thus : —

Central disc flat. With small septal nodes, A. dairdii Fewkes. With large
septal nodes, A. valdiviae Vanhiffen.

Central dise, with radial furrows, lappets smooth. With narrow furrows,
A, verrillii Fewkes. With broad furrows, A. wyvillei Haeckel.

These may later prove to be synonymous, in which case the earlier name,
A. wyvillei, must be retained.

Central dise, with narrow radial furrows and marginal lappets with nettle
warts, A. chuni Vanhiffen. This species, since its discovery by the “ Val-

divia,’ has been taken by the “Scotia” (Browne : 08).

ATOLLA WYVILLEI,

39

Two other species, A. gigantea and A. alexandri, described by Maas ('97)

from alcoholic specimens, seem to me rather problematical.

A. alexandri, it is

true, has since been recorded by Agassiz and Mayer (: 02) and by Mayer (: 06)
from the Pacific ; but examination of the three specimens on which these

two records were based has shown that, instead of having the extremely
broad central disc characteristic of A. alexandri (Maas, ’97,: 03, p. 16), their

proportions agree with those of the present series ;

and that they all show

broad radial furrows, for which reasons they must be referred to A. wyville?,

not to A. alexandri.

The specimens taken during the expedition of the “ Albatross” to the

Fastern Pacific are all of one species, which I have identified as A. wyvillet on

account of the form of the radial furrows of the central disc.

Atolla wyvillei Haeckel.

Atolla wyvillei Haeckel, ’80, p. 488; ’82, p. 113, pl. 29, figs. 1-9; Vanhéffen,: 02°, p. 13,
Browne,: 08, p. 241.

Plate 8, Fig. 7; Plate 9, Fig. 3; Plate 10, Figs. 8, 9.

taf. 5, fig. 22;

Station.

4645
4646
4647
4651
4651
4652
4655
4672
4675
4726

Trawl, 2005
Trawl, 2222

300 to surface .
Trawl, 1700

Depth, fathoms, valine Nuniber ‘ot Preservation.
In trawl, 2955. 55 24. Excellent.
300 to surface. 8 22 Good.
28 25 Poor.
about 40 ? Very fragmentary. |
800 to surface. 20 is Very fragmentary. |
400 to surface. 16 22 Fair.
300 to surface. 15 24 Good.
400 (bottom of Tanner net) 7 23 Good.
F 20 22 Good.
25 28 Fragmentary.

In addition there have been available nine other specimens, previously

collected by the “ Albatross”

at various localities in the Eastern Pacifie

including the Hawaiian Islands and coast of Southern California. All of

them show radial furrows more or less clearly.

In the largest specimen, 95 mm. in total diameter, the only visible traces

of furrows are very slight notches on the margin of the disc. In somewhat

smaller specimens, particularly in the remarkably well-preserved individual

with the disc 55 mm. in diameter, from Station 4645, the furrows, restricted

to the marginal region of the disc, show exactly the condition figured by

40 THE MEDUSAE.

Haeckel (’81, pl. 29) and by Vanhiffen (: 02°, taf. 5, fig. 22) for this species

(fig. 1). In the small specimens there is considerable variation in the

breadth of the furrows. In a specimen with the disc 20 mm. in diameter

the condition, as represented on Pl. 10, fig. 9, is that described by Van-

hoffen (: 02°) as typical of A. verrillii Fewkes, the furrows being very narrow.

I should have thought that this specimen

belonged to that species had it not been

that other small specimens showed more or

less intermediate conditions. One, 15 mm.

in disc diameter, is especially instructive,

since in it about half of the furrows are

broad, the remainder narrow, while in the

two smallest specimens with discs respec-

tively 7 and 8 mm. in diameter, most of

the furrows are broad, but in both a few

are narrow. Apparently, then, not all the

ne radial furrows in this species attain their

typical “broad” condition until a considerable size is attained. It is inter-

esting to note that both specimens of this species recorded by Vanhdffen

(: 02%, p. 13) were large, the central discs measuring respectively 37.5 and
47 mm. in diameter.

At first such variability in the form of the radial furrows would suggest
that they were of little systematic importance. Such, however, does not
seem to be the case, for Vanhdffen (:02*) has found that in a large series
(nineteen specimens) of A, verrillii they are constantly narrow, both in large
and in small individuals. This discovery suggests the very interesting con-
clusion — one, however, which may have to be modified later —that A.
verrili retains permanently a character which occurs, it may be only irreg-
ularly, in the young of the closely related A. wyvillei; but whether the two
are really valid species can hardly be settled without studies on still more
extensive series from all oceans.

The present specimens support Vanhiffen’s (: 02°) contention that there
is normally one less furrow than tentacle (Pl. 10, fig. 9), and that the full
number of antimeres is attained at an early stage.

Maas’s recent (: 03, : 04°) discovery of areas of adhesion subdividing the
tentacular canals at their bases in A. valdiviae and A. bairdii gives fresh interest

to a study of the canals,

PELAGIA. 4]

In the present series the general condition of the canal system is that
described by Maas, the rhopalar canals being narrow, the tentacular canals
broad; but there are no traces of any septal divisions in the tentacular
canals, a result also reached by Mayer (: 06). This I was able to establish
beyond doubt by examining all the canals in several excellent specimens.
Absence of adhesion areas in 4. wyvilled suggests that the occurrence of such
structures in other species may prove to be a character of taxonomic im-
portance. The tentacular canals divide some distance before reaching the
base of the tentacle, a branch running into the lappet on either side, and
a third lobe extending to the base of the tentacle. This latter lobe ends
blindly at the base of the tentacle, as Maas (: 04°) describes, but instead of
gradually dwindling, forms on the aboral side a definite pocket, which is
apparently the result of the extreme development of the tentacular mus-
culature, being squeezed down, as it were. between the muscular masses on
either side of it.

No colored figure of A. wyvillei has previously appeared. The general
coloration (Pl. 8, fig. 1; PI. 9, fig. 3) is the same which has so often been
described for other members of the genus.

A. wyvillei has previously been recorded only from antarctic and subant-
arctic stations.

DiscoPHORA.

Only two representatives of this order were taken during the expedition,
—a Pelagia, and a species apparently belonging to the remarkable new
genus Poralia described by Vanhitfen (:02*) from the collection of the
“ Valdivia.”

Pelagiidae.

Pelagia Péron et Lesueur, 1809.

Pelagiidae with 1 x 8 tentacles.

I am in considerable doubt as to what specific name to apply to the
specimens of Pelagia in the collection. In no genus of Medusae is revision
more needed than in Pelagia; but most of the descriptions of the different
species are so unsatisfactory in regard to just those features which may
reasonably be supposed to be of specific importance, that any attempt at
rearrangement is hopeless, without the study of extensive collections from
all oceans. It seems certain, however, especially from the studies of Van-
héffen (:02*) on the “Valdivia” collection, that not all of the fourteen

42 THE MEDUSAE.

described species have a basis in fact. The features on which most of them
have been based— proportions of the bell, length of the mouth parts,
color, and form of the nematocyst papillae—were long ago shown by
Haeckel (’80) to be so variable as to make him doubt whether the various
forms are anything more than geographic races; but whether they deserve
even this rank is by no means certain, inasmuch as it appears that the
different types are not constant for different oceans. Thus, specimens with
a very short manubrium have been described from the European coast and
tropical Atlantic (P. perla Haeckel, 80; Maas, : 04°); from Bering Sea (P.
denticulata Brandt, 38), and from Zanzibar, the Philippine Islands, and the
coast of Peru (P. placenta Haeckel, ’80, p. 510; Vanhéffen, 88, p. 12). A
like condition is also true of specimens with a long manubrium (P. pan-
opyra, P. cyanella) and for those with a manubrium of medium length.

So variable, moreover, is this character, and also the form of the nettle
warts, even in a single swarm, that Vanhiffen (: 02*) found it impossible to
distinguish more than one species in the vast region, including both Atlantic
and Indian oceans, traversed by the “ Valdivia.” Fortunately Vanhoffen
(: 02%, p. 36) has given us measurements of a very considerable series, —a
precaution neglected by most previous authors, —and from these I am able
to determine that the present specimens show no deviation from his, but
stand at about the middle of his series. Neither do they show any important
difference from his account in the form of the nettle capsules. From Mayer’s
(: 06) figures this is evidently true also for specimens from the Hawaiian
Islands, and apparently also for the specimens recorded by Maas from
the collections of the “Siboga,” and from Amboina.

It appears, then, that one species of Pelagia occurs in the warmer re-
gions of the Pacific, Indian, and Atlantic oceans, — a conclusion easily recon-
ciled with its mode of development without any fixed stage, and in entire
harmony with the known distribution of such other oceanic Medusae as
Periphylla hyacinthina, Rhopalonema velatum, and Aglaura hemistoma, as well
as with the uniformity of the holoplanktonic fauna in general; but that it
is the only species of the genus in these regions is by no means certain. In
deciding what specific name to apply to this form, it seems to me best to
follow Maas (: 03, :06°) and Mayer (: 06) in using the name of the earliest
described Pacific species, P. panopyra Péron, inasmuch as there is still reason
to believe that the two Atlantic species P. perla Slabber and P. noctiluca
Pér, et Les. are specifically distinct. Maas (: 04°), who had previously

PELAGIA PANOPYRA. 43

had an opportunity (:03) of studying specimens of P. panopyra, believes
that the extremely short manubrium and the fact that the mouth arms are
separated almost to its base serve to distinguish P. perla from the latter, and
it is therefore best to retain these two species as well as P. cyanella, at least for
the present; for we must bear in mind that it is quite as possible to reduce
species too much as increase them too much, and that reduction so excessive
as to result in the masking of constant varieties, no matter how closely re-
lated they may be to one another, is much more harmful than any degree
of reduplication in nomenclature.

Pelagia panopyra Péron.

Medusa panopyra Péron, :07, pl. 31, fig. 2.

Pelagia panopyra Péron et Lesueur, :09, p. 349; Brandt, ’38, p. 382, taf. 14, fig. 1, taf.
14a, figs. 1-5 ; Haeckel, ’80, p. 509; Maas, :03, p. 29; Mayer, :06, p. 1139, pl. 2,
figs. 3, 4.

Pelagia phosphora Haeckel, ’80, p.506; Vanhoffen, : 02, p. 36.

Pelagia placenta Haeckel, ’80, p. 510; Vanhoffen, ’88, p. 12.

Pelagia tuberculosa Couthouy, in L. Agassiz, ’62, p. 164.

Cyanea labiche Quoy et Gaimard, ’24, p. 571, pl. 84, fig. 7.

? Pelagia tahitiana Agassiz and Mayer, :02, p. 158, pl. 8, figs. 34, 35.

Plate 1, Fig. 1.

So long as our knowledge of the various other species of the genus
remains as incomplete as it is at present, it does not seem worth while to
attempt any fuller synonomy of P. panopyra than that given above.

Station 4587; 300 fathoms to surface; 5 specimens, 5-7 mm. in diameter.

Station 4675; surface; 1 specimen, 60 mm, in diameter, fragmentary.

Station 4692; surface; 1 specimen, 40 mm. in diameter, excellent
condition.

Station 4696; surface; 1 specimen, 20 mm. in diameter, excellent
condition.

Acapulco Harbor; surface; many ephyrae, probably referable to this
species.

Measurements of two specimens are : —

Station. Diameter. Length of manubrium, Length of mouth arms,

4692 40 18 33
4696 20 10 25

44 THE MEDUSAE.

Neither of these two specimens shows the very long manubrium which
Haeckel (’80) believed to be the chief characteristic of this species. So
far as the above dimensions are concerned, they fall well within the limits
of Vanhiffen’s (:02*) more extensive series. ‘The nettle warts are nearly
round in the smaller specimen, more oval in the larger, and in both of
moderate prominence. The marginal lappets, structures to which the earlier
authors attributed considerable systematic value, are about as broad as long,
and slightly incised at the margin so as to form two lobes; but the depth
of the incision varies even in the different lappets of a single specimen, and
therefore cannot be considered of much importance. The bell is less globu-
lar than it is usually described for P. cyanella, being considerably flattened at
the aboral pole. The gonads in the larger specimens are well developed.

The ephyrae, taken in Acapulco Harbor, which I refer to this species,
closely resemble the ephyra of P. cyanella (L. Agassiz, 62).

Color. —In the specimen from Station 4692 the dise was colorless, the
gonads, tentacles, subumbrellar surface, and the four perradial ridges of
manubrium and mouth arms pink-violet. The specimen from Station 4696
was of the same general color but much paler. An excellent colored figure
has been given by Brandt (’38).

Poralia Vanhéffen, 1902.

This genus was founded by Vanhiffen (: 02*, p. 41) for a single fragmen-
tary discophore remarkable because of its apparently octoradial type and
simple canal system. Unfortunately the entire margin, with all the tentacles
and rhopalia, was destroyed, so that he was unable to suggest any systematic
relationship for the genus.

Two specimens in the present collection seem best referred to this genus,
although, if this identification be correct, it would seem that the “ Valdivia”
specimen was immature, and, therefore, that the description of the genus
given by Vanhéffen must be modified. Unfortunately none of the three
specimens, so far referable to the genus, has been in good enough condition
to low of any satisfactory description, so that it is impossible to tell whether
or not the present ones are specifically identical with P. rufescens Van-
hiffen, the type of the genus; but it is best, at least until better material

is available, to include them under that name rather than to add a new
name on doubtful grounds.

PORALIA RUFESCENS. 45

Poralia rufescens Vanhoffen.
Poralia rufescens Vanhdffen, : 023, p. 41, taf. 4, figs. 15, 16.
Plate 13, Figs. 1-5.

Station 4647; trawl; 2005 fathoms to surface; 1 specimen, about 250
mm. in diameter.

Station 4701; 300 fathoms to surface; fragments (about half) of a
smaller specimen, about 75 mm. in diameter.

The larger specimen of the two is much the better preserved, and,
although part of the margin, all the tentacles, and nearly the entire mouth
parts are destroyed, allows of the description of several very important
features, especially with regard to the gonads, canal system, and rhopalia.

The canal system, as already noted by Vanhiffen (: 02"), is exceedingly
simple, but the canals are nearly twice as numerous in the present specimen as
in that of the “Valdivia.” Forty-one canals arise from the periphery of the
circular gastric cavity; but since two of these anastomose, only forty extend
to the margin of the disc (PI. 13, fig. 7). They are broad, and for the most part
nearly straight, though several of them show short blind branches. Unfor-
tunately it is impossible to state certainly the normal number of rhopalia,
only five being intact. However, I feel confident that I have been able to
determine the positions of twelve such organs (Pl. 13, fig. 7), and since a
considerable space along the margin is destroyed, it is probable that, as in
Callinema, there were sixteen. Fortunately, enough of the margin is intact
to allow me to trace the outer portions of the canals with some accuracy.
Some little distance within the margin these unite (PI. 13, fig. 7) to form a
continuous ring canal. Distal to the ring canal the intermediate (tentacu-
lar?) canals extend out into the marginal lappets and end blindly. The
rhopalar canals branch trichotomously, a narrow median branch running into
the rhopalium (PI. 13, fig. 5, r.c.), while the two lateral branches end blindly.

It is impossible to give any accurate account of the marginal lappets, but
from such portions of the margin as are intact it appears that the latter is
deeply incised in the radii of the rhopalia, while between these organs it seems
to have a rather wavy outline.

The rhopalia (Pl. 13, figs. 4, 5) very closely resemble the sense organs
described by the Hertwigs (’78) for Phacellophora sicula Haeckel. The sense
organ is covered by a prominent scale, beneath which it stands in an almost

46 THE MEDUSAE.

vertical position. The terminal otocyst is large, but the ventral bulbus is only
slightly developed. Just proximal to the sense organ is a deep exumbral pit
(Pl. 13, figs. 4, 5, p.) as in many discophores, perhaps sensory in function.

The gonads, which, fortunately, are in very good condition, are by far
the most interesting feature of the specimen. They are not located in
genital pouches, but form a practically continuous band surrounding the
basal portion of the stomach proper. Close examination shows that this
band is not truly continuous, but is broken by eighteen or nineteen thick-
ened vertical ridges of the gastric wall (Pl. 13, figs. 1, 3). The gonads
themselves consist of a series of outpocketings of the gastric wall projecting
out into the subumbrella cavity, their cavities (Pl. 13, fig. 3, g 0.) opening
freely into the basal part of the stomach (PI. 13, figs. 2,3). The very numer-
ous gastric cirri are arranged in a single continuous series, arising from the
wall just distal to the genital folds (Pl. 13, figs. 1-3). The gonads are
mostly emptied of their contents.

The smaller specimen includes about half of the central portion of the
disc, the entire margin and distal mouth parts being destroyed. There are
twenty-one canals in the fragment, therefore the total number was probably
about forty, as in the larger specimen. In the present specimen, however,
they are much narrower, and the intercanal spaces much broader, than in
the latter. The gonads present the same appearance, but, on the fragment,
there are four pillars subdividing the gonads, so that probably there were
only about eight in the complete medusa, instead of eighteen or nineteen as
in the larger specimen.

In the larger specimen the subumbrellar surface is reddish brown; the
gonads very pale brownish. In the smaller the entire fragment is of a deep
reddish-brown tint.

The remarkable structure of the gonads outlined above may be easily
derived as the result of an advanced stage in growth from the more primi-
tive condition described by Vanhiffen for his much smaller specimen.
He has described and figured (: 02°, p. 41, taf. 4, figs. 15, 16) seven (eight ?)
gonads, each consisting of three or four outpocketings of the gastric wall,
lying, not in gastric pouches, but directly at the base of the gastric cavity,
exactly as in the present specimens. To attain the condition exhibited by
the smaller “ Albatross” specimen, we need only suppose that with growth
the gonads increase in width by the formation, on either side, of new sexual
folds, until the adjacent gonads practically unite. The spaces between them

NARCOMEDUSAE AT

would then be narrowed until represented merely by the eight (?) ridges or
pillars seen in our smaller specimen. The fact that in the larger specimen
there are eighteen or nineteen such gastric ridges, instead of seven or eight,
is difficult to explain.

The affinities of this peculiar genus must remain problematical until more
satisfactory material with tentacles intact can be studied. In the structure
of the canals and of the bell margin the present specimens closely resemble
Callinema ornata Verrill, especially the fragmentary specimen recently re-
corded by Browne (: 08) under that name from the “ Scotia” collection. The
structure of the gonads (apparently not preserved in Browne’s individual) puts
identity, or even close relationship, with that species out of the question.

The most remarkable feature of Poralia is, of course, that it is probably
octoradial in its younger stages, a conclusion of which the “Valdivia” speci-
men leaves little doubt, although the latter had only seven gonads. As
Vanhiffen (: 02°, p. 41) has pointed out, octoradial Medusae had previously
been known among discophores only as abnormalities of Awrelia awrita. Since
however they are extremly rare even in this form, this second capture of
Poralia practically eliminates the possibility that this genus can be abnormal.
The structure of the gonads gives us but little assistance in this question,
as the development of the genital folds directly from the aboral wall of
the stomach, without the formation of gastro-genital pockets or well-marked
subgenital pits, appears to be the primitive condition among the Discophora,
occurring among Cyanidae and the more primitive Pelagidae and Ulmaridae.

CRASPEDOTAE.
NARCOMEDUSAE Haeckel, 1879.

The collection contains twelve species of Narcomedusae, representing
ten genera, on which to test the classifications of the order recently pro-
posed by Maas (:04*, : 04°) and Vanhiffen (: 07). These two plans rest
on radically different bases; for while Maas has discarded the presence
or absence of a peripheral canal system as sound ground even for generic
diagnosis, Vanhéffen believes that this character, in conjunction with the mode
of development, whether direct or indirect, is sufficiently important to war-
rant the division of the Narcomedusae into two suborders, Diocheteumena
having, and Adiocheteumena lacking, canals. There are, however, strong

objections to assigning such importance to the presence or absence of the

48 THE MEDUSAE.

canal system, for not only do species otherwise closely allied differ in this
respect (e.g. in the genera Cunoctantha and Cunina), but different genera
may exhibit gradations in the degree of development of the canals; so that
it is impossible to draw any sharp line between those in which they are
developed and those in which they are rudimentary. Furthermore, it has
already been shown conclusively that in at least one species with canals,
zt. e. Cunina proboscidea Metschnikoff, a secondary generation of medusae
without canals is developed, —an observation I have been able to repeat on
a second species, Pegantha smaragdina, sp. nov. A further criticism is that
it is, to say the least, questionable whether either Aegina or Aeginura,
included by Vanhéffen in the Diocheteumena, ever possesses a well-developed
canal system, Maas (: 05) having found it rudimentary in both. The use of
the mode of development as a basis for classification in this order would seem
at least premature, since as yet in only three genera (Cunoctantha, Cunina,
and Pegantha) do we know positively that it is indirect; and if this feature
should be employed, it is incompatible with Vanhéffen’s scheme, since one of
the species in which it is known to be indirect, Cunoctantha octonaria McCrady,
which should therefore belong to the Diocheteumena, has been shown by
the miscroscopic studies of Wilson (’87) to lack any trace of a canal system,
a character placing it in the Adiocheteumena.

A much more important character, since it is more constant and appar-
ently more closely correlated with the natural relationships between species,
and one on which Maas (: 04*, : 04°, : 05) has laid special stress, is the presence
or absence of gastric pockets.

It is true that there is some evidence (e.g. in Cunina proboscidea) that these
structures, like the canals, may be present in one generation while absent in
the other. But this evidence is not altogether conclusive, since it is now well
known that in at least one species, Cunoctantha octonaria, the pockets are
not formed until a stage in growth much more advanced than that to which
either Metschnikoff (’86*) or Stchelkanowzew (: 06) have traced the secondary
generation of Cunina proboscidea. Vanhitfen (:07) has himself employed this
character to separate two families, Aeginidae and Peganthidae, under the
suborder Diocheteumena (with peripheral canal system), but he has entirely
neglected it in the second suborder, Adiocheteumena, apparently believing
that Solmaris may have gastric pockets, whereas all previous students agree
that in this genus, as well as in the well-known Mediterranean Sodmoneta

Sluvescens, the conditions of the gastric cavity exactly parallels that in Pegan-

NARCOMEDUSAE. 49

tha, there being no true gastric pockets at any stage in development.
Finally, I may call attention to the fact that the employment by Vanhéffen
of a single character, 7. ¢. number of tentacles as the sole basis of generic
separation in this complex group, has resulted, as might have been ex-
pected, in such unnatural combinations as Cunoctantha with Aeginura and
Cunina with Aegineta, genera with which they are but distantly related as
is shown by the condition of the gastric pockets, and by the otoporpae; and
of Solmissus with Solmaris, genera sharply separated by the presence of
gastric pockets in the former and their absence in the latter.

On the whole, the scheme proposed by Maas (: 04°, :04°) much more nearly
represents what I believe to be the probable natural relationships among
the Narcomedusae. According to Maas Narcomedusae in which gastric
pockets are present are to be subdivided into two families, Cunanthidae and
Aeginidae, according as the pockets are radial and equal in number to the
tentacles, or adradial and twice as numerous as the latter; but as to whether
the latter condition is actually derived from the former by the secondary divi-
sion of pockets primarily radial, it is perhaps best to reserve judgment, since
the present collection contains one species with interradial pockets equal in
number to the tentacles, a condition hardly to be derived from one with
radial pockets. Opposed to these two families are the Solmaridae, in which
there are no gastric pockets.

There are, as Maas (: 04) points out, strong reasons for believing that the
two families with gastric pockets are more nearly related to each other than
is either of them to the Solmaridae; and Dr. A. G. Mayer, who holds this
same view, has suggested to me the desirability of uniting all Narcomedusae
with gastric pockets into a single family, reducing the Cunanthidae and
Aeginidae to the rank of subfamilies. I doubt, however, whether to take
this step would result in advancing our knowledge of the true phylogenetic
relationships of the various members of this complex group; for although
the similarity of the Cunanthidae as a whole to the Aeginidae is no doubt
close, yet Solmissus, a cunanthid, so closely simulates certain Solmaridae,
e.g. Solmaris and Solmoneta, in the peculiar form of its sense organs, that it
is hard to believe that the resemblance is accidental. In all probability our
knowledge of the development of the Narcomedusae will be greatly widened
within the next few years, with the result of giving a much firmer basis for
revision than is possible from the descriptions of the adult stages as yet
published. In the meantime it seems to me that we may well retain Maas’s

provisional diagnosis of the families composing the order, as follows : —
4

50 THE MEDUSAE.

1. Cunanthidae; gastric pockets undivided, equal in number to the ten-
tacles; with or without peripheral canal system ; with or without otoporpae.

2. Aeginidae; gastric pockets adradial (in adult), usually twice (or four
times) as numerous as the tentacles (an exception to the rule is seen in Aegina
allernans) ; with or without canals; without otoporpae so far as known.

3. Solmaridae; without gastric pockets; with or without canal system and
otoporpae.

Besides the light which the collection throws on the classification of the
group, it is very important, since it contains examples of two methods of re-
production : — internal budding, and development of a secondary, parasitic
generation of medusae. Since the first of these has never been conclusively
demonstrated, the discovery that a form of internal budding does occur in
this order is of unusual interest, even though only the earlier stages in the
process can be traced. The development of a parasitic generation directly
from the egg in the body of the parent host has already been described by
Metschnikoff (’86*), under the name “sporogony,’ and by Stchelkanowzew
(: 06), for Cunina proboscidea Metsch. The process is so rare, and so remark-
able on account of the occurrence in the one species of two alternating gener-
ations of medusae of different anatomical characters, that a repetition of
the observations for another family (Solmaridae) is of great interest. I
should add that in addition to the modes of development outlined above there
have been described for various Narcomedusae direct development from
the egg, budding from stolons parasitic in various medusae (Cunina, Cunoc-
tantha), and the ordinary external formation of medusa buds (Cunoctantha,
Browne, : 06).

Cunanthidae Haeckel, 1879.
sens. em. Maas (: 04", :04°).

Narcomedusae with undivided radial gastric pockets, equal in number to
the tentacles.

Of the five genera distinguished by Haeckel under this family, Maas has
shown that two only, Cunoctantha and Cunina, really belong here. Of the
three remaining, Cunarcha and Cunissa belong to the Aeginidae, since they
have divided gastric pockets twice as numerous as the tentacles, while the
third, Cunantha, seems almost certainly to be based on larval stages of either
Cunoctantha or Cunina. According to Maas’s classification, which I have
adopted, Solmissus, classed by Haeckel (79) under the Solmaridae because it
has neither canal system nor otoporpae, must be referred to the present family

because of the conformation of its gastric pockets.

CUNOCTANTHA. 51

Cunoctantha and Cunina differ from each other only in the number of
tentacles, for while it had previously seemed that the presence of canals in
Cunina and their absence in Cunoctantha might be a good generic character,
the occurrence in the present collection of a typical Cunina without any trace
of canal system, and of a typical Cunoctantha with canals well developed,
proves that this view is untenable. More important, perhaps, than the dif-
ference in the number of metameres in these two genera, though previously
less emphasized, is the fact that in one, Cunoctantha, they are determinate
in number; in the other, variable in all species so far known. Solmissus differs
from both in the absence of otoporpae,—structures which occur in all species
of Cunoctantha and Cunina, at least in the primary generation.

Cunoctantha Haeckel, 1879.

Cunanthidae with only eight tentacles ; with otoporpae ; with or without
peripheral canal system.

Maas (: 05) has shown that the several supposed forms which can be
grouped under this genus probably form not more than two distinct species.
These are C. octonaria McCrady (57), including C. kéllikert F. Miiller (°61*) and
C. incisa Mayer (: 00°) ; and C. discoidalis Keferstein and Ehlers (’61), synonyms
of the latter being C. parasitica Metschnikoff (’81), and C. polygonia Haeckel
(79). For the latter Maas has used Metschnikoff’s name, C. parasitica, but from
an examination of the figures given by Keferstein and Ehlers (61, taf. 14,
figs. 12-14), I am convinced that the specimens which they examined were
early stages of C. parasitica, from which they differ only in having but one
otocyst per lappet and very short gastric pockets, both of which characters
were observed by Metschnikoff (’81) in the development of the latter species,
so that it seems best to retain the older name C. discoidalis.

Maas (: 05) has expressed some doubt as to whether Cunoctantha octonaria
and (. discoidalis will finally prove to be distinct. The chief reason for their
separation, is the supposition that different methods of development occur in
the two forms, C. parasitica forming stolons, while the medusae of C. octonaria
develop directly, but F. Miiller ( 61") observed stolons in the development of
C. kiillikeri (certainly a synonym of C.octonaria), and Mayer (: 04) found a free
floating stolon of some species of this genus at Tortugas, Florida, where he
has also taken C. octonaria (incisa). Unfortunately Mayer was unable to raise
the medusae far enough for specific determination, but the stolon closely

resembled the one described by Miiller.

52 THE MEDUSAE.

Even if this supposed difference in development does not exist, there
is another character, of considerable value, which does distinguish the two
species and this is the number of otocysts per marginal lappet. It is true that
Maas considers this feature of no systematic importance, because in C. octonaria,
as well as in C. parasitica an increase, with development, of from one to three per
lappet has been observed (McCrady, ’57; Brooks, ’86; Miiller, 61°); but
this number (three) appears from the studies of Brooks (’86), Mayer (: 00°),
and Maas himself (: 05) to be the normal limit which is reached in C. octonaria ;
for although Maas observed occasional lappets with four octocysts, it is
likely, since three have so usually been observed in adult specimens of this
species, that a greater number is, as Maas suggests, a sporadic variation.
In C. parasitica, however, Metschnikoff has observed stages in develop-
ment up to the formation of five per lappet, and suggests the possibility of
a still further increase; while Haeckel had already observed seven per lappet
(C. polygonia). In neither of these species is there any peripheral canal
system (Wilson, °87, p. 99; Maas, : 05°). Browne (: 06) has described re-
cently another Cunoctantha, C. fowler’, from the Bay of Biscay, but his speci-
men, which showed external budding, had no gonads, so that its final
disposition must remain doubtful.

To these species there must now be added @. tenella, sp. nov., from the
present collection, in which a canal system is well developed. I do not
hesitate to place this species in Cunoctantha, since, though only one of the
specimens is sexually mature, all (seven) have eight tentacles. In view of
the fact that in Cunina species with and species without canals (C. peregrina)
occur, and that even in one species (C. proboscidea) one generation may have,
the other lack, canals (Metschnikoff, 86"; Stchelkanowzew, : 06), there is
nothing surprising in finding a parallel series of forms in the closely related
genus Cunoctantha.

Cunoctantha octonaria McCrady.
Cunina octonaria McCrady, ’57, p. 211, pl. 12, figs. 4, 5.
Cunoctantha octonaria Haeckel, ’79, p. 316; Brooks, ’86, p. 361, pls. 43-44; Maas, : 05,
p. 67, taf. 12, figs. 77, 78, taf. 13, figs. 83-85.
Cunoctantha incisa Mayer, : 00°, p. 66, pl. 44, figs. 745, 146.
Foveolia octonaria A. Agassiz, ’65, p. 51.

Plate 14, Fig. 4; Plate 15, Figs. 5,6; Plate 17, Figs. 2, 4, 5.

Acapuleo Harbor; many specimens, 1.5-4 mm. in diameter.

The largest specimens (PI. 14, fig. 4), none of which are sexually mature,

CUNOCTANTHA OCTONARIA. 53

very closely resemble the figure given by McCrady (57, pl. 12, fig. 4) of a
half-grown specimen of this species, 6 mm. in diameter. The bell is high,
either rounded or somewhat pointed ; the exumbrellar surface smooth. The
margin is deeply incised in the radii of the peroniae, so that the latter are
comparatively short. Below the point of insertion of each tentacle there
is a nematocyst pad. The adult number of otocysts, three per lappet, has
already been attained, but the central one in each lappet is still much
larger and shows structurally a later stage of development than the two
lateral ones (PI. 17, fig. 2). Each otocyst is connected with an otoporp or
“auditory clasp,’ the ones in the centres of the lappets being the longest.
These otoporpae form very pronounced ridges on the gelatinous exumbrella,
and are undoubtedly what McCrady (57°) and Maas (: 05) have described as
“fleshy tubercles.” They have likewise been observed in this species by
Brooks (86) and Mayer (:00). McCrady (57°) was correct in supposing
that they contained “thread cells.” The otocysts themselves are of the
usual “ Cunina” type; those furthest developed contain one or two otoliths,
and the low prominences of the urticating ring on which they stand bear
bristles (Pl. 17, fig. 2). In the small specimens 1.5-2 mm. in diameter
(Pl. 15, fig. 6) there is, as McCrady (’57), Brooks (’86), and Maas (: 05) have
noted, only one otocyst per lappet, but this octocyst is already connected
with an otoporp.

The gastric system resembles the figures given by McCrady (’56, °57), and
Brooks (86) for corresponding stages. In the smallest specimen no gastric
pockets have yet been formed, although the future appearance of these is
already suggested by a slight lobing of the margin of the stomach in the radii
of the tentacles (PI. 15, fig. 6). In aspecimen 4 mm. in diameter the pockets are
already developed, but are still shallow, and separated by wide septal regions.
This is practically the condition found by McCrady (757, pl. 12, fig. 4). We
know, however, from the studies of Brooks (86), who was able to follow the
development of this species further, that this condition is not the final one, but
that in adults the pockets are nearly rectangular, rather longer than broad,
and separated only by very narrow, almost linear, septal areas, an observation
confirmed by Maas (: 05) for large specimens in the “ Siboga ” collection.

None of the specimens as yet show any trace of gonads.

Color. — The margin of the gastric cavity is brown (Pl. 14, fig. 4); this
region is described by McCrady as being yellow; evidently, then, the pig-

mentation is variable. Otherwise, the medusa is colorless.

54 THE MEDUSAE.

This species is widely distributed, having been recorded from the eastern
coast of North America (McCrady, ’57°, Brooks, 86), the Gulf of Mexico
(Mayer, : 00°), the Malay Archipelago (Maas, : 05), the Fiji Islands (Agassiz
and Mayer, 799), and from the west coast of Mexico by the present
expedition.

Cunoctantha tenella, sp. nov.
Plate 15, Fig. 4 Type; Plate 16, Fig. 2; Plate 17, Figs. 6, 7.

Acapulco Harbor, surface. Many specimens, 2-7 mm. in diameter.

The bell in a specimen 5 mm. in diameter is 3.5 mm. high, its surface
smooth. The marginal zone and lappets are very narrow and but slightly
incised in the radii of the tentacles. The peroniae are correspondingly short,
and consist chiefly of kidney-shaped nematocyst pads underlying the bases of
the tentacles, such as oceur in C. octonaria and Cunina peregrina. These strue-
tures have been described and figured in detail for C. octonaria by Wilson (’87).
There are eight tentacles in every specimen whether small or large, good
evidence that this is the typical number, and that the species belongs to the
genus Cunoctantha, not to Cunina. In the larger specimens there are three
otocysts per lappet; in the smallest, however, 2 mm. in diameter, there is
only one in each lappet (Pl. 16, fig. 2). No lappet in any specimen bore
more than three, but inasmuch as it is doubtful whether any of them had
reached their extreme size it is possible that more might be developed. The
sense organs themselves (P]. 17, fig. 7) closely resemble those of C. octonaria,
containing, like the latter, one or two otocysts, and being situated on low
prominences of the nerve ring. Each otocyst is connected with a short
otoporp, although in the present species these do not form such prominent
ridges as they do in C. octonaria.

C. tenella is interesting chiefly for the fact that while in the number
of its tentacles, gastric pockets, and marginal lappets it is a typical Cunoc-
tantha, it yet exhibits a well-developed peripheral canal system, a feature
entirely lacking in the two species of this genus previously known, The
peronial canals are very short, corresponding to the short peroniae ; but they
and the festoon canal are both rather broad (PI. 17, fig. 7). The central
stomach also shows an interesting feature in that the gastric pockets, instead
of being nearly rectangular, as in most other members of the Cunanthidae,
are almost triangular, as is shown in the general sketch of the Medusa

(Pl. 15, fig. 4). This form of the pockets is to be seen even in the smallest

CUNINA. 55

specimen, only about 2 mm. in diameter (PI. 16, fig. 2). Although there is
no proboscis, the mouth being surrounded by a simple circular lip, the
stomach cavity is deeper than is usual in this family, owing to the arched
form of its aboral wall (PI. 15, fig. 4).

The only specimen showing any trace of gonads was the largest (7 mm.
in diameter). In this individual, apparently a male, the sexual products
form thickenings of the ventral surfaces of the gastric pockets.

The medusa is entirely colorless.

Cunina Eschscholtz, 1829.

sens. em. Maas (: 04? : 04°).

Cunanthidae with otoporpae and with nine or more tentacles and mar-
ginal lappets.

In attempting an identification of the two species of Cunina in the present
collection I have been forced to attempt a rough revision of the genus; a
difficult task on account of the unsatisfactory nature of most of the early (and
even some of the later) descriptions and figures, as well as because our
knowledge of the young stages is still too scanty to be of much assistance
in the systematic study of the genus. To make a final revision is entirely
out of the question, unless one has access to much more extensive collections
than I have studied; but so puzzling is this genus that I have thought it
well to add certain conclusions which I have myself reached, in the hope
that they may help to clear the ground for future students.

In Haeckel’s (’79) “system”’ ten species are listed with numerous synonyms.
It is evident, however, that the distinctions between them are by no means
satisfactory, and that his treatment of the older species is in some cases mis-
leading. To begin with, it seems to me essential to eliminate entirely as xom-
ina nuda such names as are based on unrecognizable figures or descriptions ;
on descriptions equally applicable to any member of the genus; or on speci-
mens so poorly preserved as to be specifically unrecognizable. From this
standpoint I have concluded to abandon the following, since there seems no
possibility of ever certainly identifying them : —@. vitrea Gegenbaur, because
the only figure and description are insufficient, C. mucillaginosa de Blainville,
for the same reason, the description being equally applicable to any mem-
ber of the genus; C. oligotis Haeckel and C. striata Metschnikoff, because they
are evidently founded on larval specimens, whose connection with adult

56 THE MEDUSAE.

species it is impossible to determine ; and probably C. multifida Haeckel,
because founded for a very fragmentary alcoholic specimen, which may not
belong to the present genus at all. The remaining species enumerated by
Haeckel (°79) are C. globosa Eschscholtz, C. campanulata Eschscholtz, C. lativen-
tris Gegenbaur, C. prolifera Gegenbaur, C. rubiginosa Kolliker, and C. rhodo-
dactyla Haeckel. Eschscholtz’s figures and description of C. globosa are, as
usual, recognizable, and agree with one of the species in the present collec-
tion. Haeckel has classed C. globosa Gegenbaur as a synonym of this species.
Stchelkanowzew (:06) has doubted the correctness of this conclusion, chiefly —
it seems on grounds of geographic distribution; but there seems to be
nothing in Gegenbaur’s figure to show that his specimens differ from
Eschscholtz’s species, and as differences in distribution certainly are not
fit grounds for specific distinctions, I shall include it as a synonym of the
latter, unless, indeed, it might be better to regard Gegenbaur’s name as a
nomen nudum, on account of the rather insufficient nature of his description.
C. globosa is certainly very closely allied to C. dativentris Gegenbaur, the main
differences being merely in the form of the bell and of the otoporpae.
C. lativentris Gegenbaur is the best known and most often recorded member
of the genus. It is taken regularly in the Mediterranean, and has recently
been recorded by Maas (: 04°) from the Atlantic. Strange to say, however,
no altogether satisfactory figures of it have ever appeared. As to the status
of C. campanulata Eschscholtz, not recorded, so far as I can learn, since first
described, it seems impossible to reach any conclusion of value without a
study of fresh material. There is good reason for believing that C. rubiginosa
K6lliker and C. rhododactyla Haeckel are identical, since Metschnikoff (’86”) has
found all intermediate stages between the two, and concludes that Haeckel’s
specimens of C. rhododactyla were merely small C. rubiginosa. This view is
likewise held, though with reservation, by Maas (: 04°), but the latter author
prefers to retain the name C. rhododactyla instead of the older name C. rubi-
ginosa, because of the excellence of Haeckel’s figures of the former. This
species, which appears well characterized, has been recorded frequently from
the Mediterranean and recently (Maas : 04°), from the Atlantic. C. prolifera
Gegenbaur is a doubtful species. In many respects, e.g. number of radial
parts and number of otocysts per lappet, it resembles C. rubiginosa and may
perhaps be a synonym of that form.

It is very important to know the true status of C. proboscidea Metschni-

koff, since it has been the basis of the very valuable embryological studies

CUNINA GLOBOSA. 57

of Metschnikoff (’86*), and more recently of those of Stchelkanowzew (: 06),
which have resulted in the demonstration that an alternation of genera-
tions of medusae occurs among the Narcomedusae. Haeckel (’80, p. 652)
has rather cavalierly referred it to C. vitrea, and Uljanin (76) to C. lativentris.
Metschnikoff, however, in a more recent publication (’86"), argues that this is
not the case, and Stchelkanowzew (: 06), who has been able to study a large
series of C. proboscidea, has given evidence that it is a valid species. He bases
this conclusion chiefly on two characters,—the short, club-shaped otoporpae,
very different in outline from the long, narrrowly-oval otoporpae of C. dativen-
tris, and on the presence, in sexually mature individuals as well as in small
specimens, of a marked proboscis supported by a pronounced prominence
of the gelatinous disc which he likens to the “Stiel”’ of the Geryonidae.
Since Stchelkanowzew has had a very favorable opportunity to study this form,
we will do well to accept his conclusion that C. proboscidea is distinct.
Finally, we have the case of C. duplicata Maas. This species has recently
been referred by Maas (: 04°, p. 54) to the family Aeginidae. But his orig-
inal figures (93, taf. 5, figs. 9, 10) show clearly that the gastric pockets are
undivided, and equal in number to the tentacles, as is characteristic of the
Cunanthidae, while the large number of radial parts (sixteen) and the pres-
ence of otoporpae show that it is a typical Cunina. Maas (93, p. 52)
believes that it has a determinate number (sixteen) of radial parts, and if
this should prove to be the case, it would require, as he suggests, the estab-
lishment of a new genus; but, since he was able to examine only a single
specimen, it is not safe to assume the validity of this supposed character.
All the foregoing species agree in the possession of a well-developed
peripheral canal system, at least in the primary generation. A form in the
present collection, however, entirely lacks these structures and must there-

fore be regarded as a new species.

Cunina globosa Eschscholtz.

Cunina globosa Eschscholtz, ’29, p. 117, taf. 9, fig. 3 ; Haeckel, ’79, p. 319.
? Aegineta globosa Gegenbaur, 56, p. 263, taf. 10, fig. 8.

Plate 15, Fig. 3; Plate 17, Figs. 3, 8.

Station 4546 Hyd.; surface; 4 specimens, all about 15 mm. in diameter.

These specimens agree with Eschscholtz’s account in general form, in

58 THE MEDUSAE.

the breadth of the gastric pouches, and in the number (three) of otocysts on
each lappet, a character which appears to be constant, at least for the pres-
ent specimens. The bell is rather high, and somewhat conical; the gelat-
inous substance thick. In life the bell is seldom circular, but usually more
or less triangular, the result of the weakness of the mesogloea and the vigor-
ous contractions of the subumbrellar muscles, a condition common in C. /ati-
ventris (Maas, : 04°, p. 31). The exumbrellar surface is smooth, without
ridges or other sculpture. In one specimen there are fourteen, in each of
the others thirteen tentacles about as long as one third the diameter of the
bell, and frequently recurved into the cavity of the latter. In consequence
of the shortness of the marginal lappets the tentacles arise but a short distance
from the margin, There are no nematocyst pads at the bases of the tentacles
such as occur in C. peregrina, the other member of the genus taken during
the expedition. It is probable that the presence or absence of these pads
will prove, when more fully known, to be an important specific character.
Another constant difference between the two species is in the structure of
the tentacles. In @. globosa the endoderm cells forming the core of the
tentacle preserve the chordate form out to the tip of the tentacle, and near
the tip, which is slightly swollen, the ectoderm is crowded with nematocysts
(Pl. 17, fig. 3). In C. peregrina, on the other hand, the endoderm cells
become nearly cubical near the tip, and there is no such nematocyst swell-
ing. This difference does not seem to be due to different degrees of con-
traction, since it was to be seen in all the tentacles of the two species which
I examined. It may perhaps be correlated with the difference in the flex-
ibility of the tentacles in the two species, these organs being much more
mobile in C. globosa than in C. peregrina. The marginal lappets are very short,
and but slightly rounded in outline. The peroniae are correspondingly
short and covered over by the union of the gelatinous substance of the
two adjacent lappets.

The number of otocysts, three per lappet, is unusually small for the genus.
This number is constant in all the lappets of these four specimens, and since
all are sexually mature, there is no reason to suppose that the number of these
organs would increase further. The otocysts themselves (Pl. 17, fig. 8) are of
the usual Cunina type, so well known through the studies of the Hertwigs
(78) in C. lativentris, Each contains two or three large otoliths. It is
probable that in life the otoliths were more prismatic than I have rep-

resented them (Pl. 17, fig. 8), since they were not examined until after

5

CUNINA PEREGRINA. 59

preservation. The otocysts are situated on prominent ectodermic swellings,
which in life bear a number of bristles; but after preservation most of these
have disappeared. The otoporpae (PI. 17, fig. 8) are of the usual type, but so
short that they hardly reach across the ring canal, and very broad, —a form
which is constant, and very different from those of C. peregrina. The gastro-
vascular system is of the usual Cunina type, the peripheral canal system
being well developed (PI. 15, fig. 3). The stomach is fiat, but the simple
lip is capable of being considerably protruded. The gastric pouches, thirteen
or fourteen in number, are about as broad as long, nearly square in outline,
and separated from one another by very narrow septal regions.

The gonads form thickenings covering the distal half or three fourths of
the gastric pockets. All the four specimens appear to be males.

The specimens are colorless and hyaline, except for the gastro-vascular
system, which is opaque and of a faint bluish tint.

Cunina peregrina, sp. nov.

Plate 1, Fig. 6; Plate 15, Figs. 1, 2; Plate 28, Figs. 1-7; Plate 45, Fig. 8.

Station. Depth. No. specimens. | Diam., mm. | Tentacles, | Otocysts per lappet. Gonads. Preservation.
4588 | Surface 1 2 8 3-4 None | Good.

‘| 300 fms.
4590 to 1 3 9 ? None | Good.

( surface Small,
4646 | Surface 1 14 12 ? sex ? | Fair.
4661 | Surface 1 10 10 4-5 None | Fair.
4665 | Surface a 9 10 4-5 None _ | Fair.
4663 | Surface ! hi 5 10 4-6 None _ | Good.
4663 |Surface|( “tS | 43 10 5-6 3 | Good.
4663 | Surface j SEOs 13 11 4-5 Small ¢| Good.
4669 | Surface 3 10 113 6-8 a Good.
4669 | Surface at this 3 8 3-4 None | Fragmentary.
4669 | Surface station 9 10 4 in one lappet | None? | Fragmentary.
4671 | Surface 10 10 46 a Fair.
4671 | Surface 9 10 5 in one None | Fragmentary.
4671 | Surface 19 2 12 5=7 Q Good Type.
4671 | Surface at this 8 10 5 in one None | Fragmentary.
4671 | Surface station 13 9 ? is Fragmentary.
4671 | Surface 3 8 4 in one None | Fair.
4671 | Surface 5 9 ? None | Fragmentary.
4714 | Surface ul 12 10 5 in one ... | Fragmentary.
4716 | Surface 1 10 12 is ... |Fragmentary.
4725 | Surface 1 11 10 6 in one None _ | Fair.

As appears from the above table, this species was comparatively common

throughout the entire expedition.

60 THE MEDUSAE.

The largest specimen measures 14 mm. in diameter and has twelve ten-
tacles. This appears to be the maximum number of tentacles, the majority
of specimens having from nine to eleven. The smallest specimens, 2 mm.
and 3 mm. in diameter, have only eight and nine respectively, and a specimen
5 mm. in diameter has nine; all the larger specimens have at least
that number, while a large specimen, 13 mm. in diameter, has only nine. It
appears, then, that in this species the adult number of tentacles is early
attained.

The bell is rather high (Pl. 1, fig. 6; Pl. 15, fig. 2) and varies much in
outline according to the state of contraction of the specimen. The gelati-
nous dise is thick and highly arched. The marginal lappets are short and
broad (Pl. 1, fig. 6), the radial incisions separating them shallow, and the
peroniae short and covered over by the gelatinous substance of the adjacent
lappets. The surface of the bell is smooth, except for the ridges near the
margin which mark the course of the otoporpae. The tentacles are about as
long as the bell radius, and in life carried stiffly extended (PI. 15, fig. 7).
Underlying the base of each tentacle, at its pot of origin from the bell, is
an oval or kidney-shaped pad (PI. 28, fig. 4, np.), consisting of crowded ectoderm
cells, among which are many nematocysts. These pads appear to afford
a good specific character, since they are constant in occurrence.

The number of otocysts is variable, but in large specimens the number
in each marginal lappet is always much greater than three, the number
characteristic of C. globosa. The greatest number observed in any one lappet
was eight, the smallest, in a large specimen, four. ‘The most usual number
is five or six. In the smallest specimen, 2 mm. in diameter, there were
three in some lappets, four in others. The otoporpae vary considerably in
length, but never extend over much more than half of the marginal lappets.
They are narrower than in C. globosa, and of nearly uniform breadth through-
out their length (PI. 45, fig. 8). The sense organs themselves are rather
small, broadly oval in outline, and contain each a single large otolith (Pl. 45,
fig. 8). None of these organs were examined before preservation, and it is
probable that the rounded form of the otoliths is due to the corrosive action
of the formalin. In life many of the spindle-shaped cells of the ‘ auditory
pads” bear bristles (Pl. 45, fig. 8), but most of these are destroyed by
preservation,

The central portion of the gastro-vascular system is of the usual Cunina

type, the stomach flat, the mouth surrounded by a simple circular lip, often

CUNINA PEREGRINA. 61

broadly open. The gastric pockets are about as broad as long, and nearly
square in outline, as is to be seen in the photograph reproduced in
Pl. 1, fig. 6.

The most interesting feature of this species, and the one which serves to
distinguish it from all /arge species of Cunina previously described, is-that it
entirely lacks any trace of a peripheral canal system. From a surface view
it might well seem that a festoon canal was present (PI. 1, fig. 6); but the
structure which causes this appearance is in reality not a canal, but the very
prominent marginal urticating ring. This I was able to demonstrate on
series of sections of the marginal lappets.

Only two specimens, one a male, the other a female, were approaching
sexual maturity. In the male, in which the spermatozoa are nearly ripe,
the sexual products form ridge-like thickenings of the subumbral gastric wall
along the margins of the gastric pockets, there being no trace of their devel-
opment in other portions of the floor of the stomach (PI. 28, fig. 4). On the
different pockets these ridges are variously subdivided. In cross section the
sharp separation between the ridge, consisting of various generations of male
sex cells, and the remainder of the gastric wall is very striking. The female
above mentioned is less mature. In this specimen the developing eggs,
instead of occupying such a restricted region, form a uniform thickening
over the whole surface of the gastric pockets. Thus in the males and
females of this species the gonads differ in form and location.

Another interesting anatomical feature of this Medusa is the extremely
powerful musculature of the subumbrellar surface of the lappet region.
Prpbably associated with this muscular development is the fact that this
is avery active Medusa, swimming with strong pulsations of the bell and much
more rapidly than any other Narcomedusa which I have observed alive.

All the specimens were entirely colorless.

A very young specimen of this species, measuring only 2 mm. in diam-
eter, was taken on the surface at Station 4588. The bell is flat and disc-like,
the gelatinous substance very thin, and the marginal zone hardly if at all
recurved. In general appearance and in the number of tentacles (8), it
closely resembles early stages in the development of Cunoctuntha octonaria
as figured by Brooks (’86, pl. 44, fig. 3). The marginal lobes are much
shorter than in the adult, and the incisions between them extend almost to
the bases of the tentacles, so that the peroniae can as yet hardly be distin-
guished. Nematocyst pads are already developed below the bases of the

62 THE MEDUSAE.

tentacles. Unfortunately the stomach is so much damaged that the form of
the mouth cannot be determined. There are three otocysts in some, four in
other lappets, all of them already connected with otoporpae.

This is undoubtedly a surface species. The list of captures shows that it
is of very general distribution throughout the Eastern Tropical Pacific.

Cunina peregrina is, as already noted (p. 9), one of the two species in
the collection which exhibit stages in a process of internal budding. This
process, which was observed in six individuals, none of which had gonads,
takes place within the gastric cavity, and is restricted to the oral surface of
the gastric lobes. In an individual in which budding is in progress various
ridges and thickenings are to be seen in surface views. These swellings
vary greatly in form, being either ridges, or more papilliform processes, or
even globular eminences (PI. 28, fig. 2). Many of them, moreover, bear
secondary prominences, the true buds (PI. 28, fig. 6,2”). In sections (P1. 28,
fig. 7) the swellings or stolons, as they may aptly be termed, are seen to be
wholly of endodermic nature, the ectoderm, at least as a distinct layer,
taking no part in their formation. It is possible, however, though not
demonstrated, that amoeboid ectoderm cells may pass through the meso-
gloea and wander into them. I have found no evidence that these large
swellings ever become detached ; on the contrary, they are apparently noth-
ing more than the proliferating regions which give off the true buds. Three
successive stages in the formation of buds are represented, from sections, in
Pl. 28, figs. 5—7. The bud, a solid morula-like mass of about twenty-
four cells, is constricted off from the stolon, and set free in the gastric cavity,
where a considerable number were observed. I can say nothing as to their
later history, except that since no stages more advanced in development
were discovered, probably they are passed out through the mouth of the
parent, to pass through their larval stages either free or as parasites on some

other organism.
Cunina species ?
Plate 27, Fig. 8; Plate 45, Figs, 3-7.

A Cunina stolon found attached to the subumbrellar surface of a Rhopa-
lonema velatum from Station 4640, and several young medusae evidently
recently detached from it, may belong to Cunina peregrina. The stolon itself
(Pl. 45, fig. 3), about 1.5 mm. in length, bears buds in all stages of develop-

ment. Since these closely resemble the stolon-buds described by many other

SOLMISSUS. 63

authors, they need not be described here further than to note that a long
proboscis is developed very early, whereas the tentacles remain short and
rudimentary until after the young medusae have been liberated (PI. 45,
fiz. 4). This feature is probably of specific significance. The smallest liber-
ated medusa, represented in Pl. 45, fig. 4, has six rudimentary tentacles.
The marginal lappets are already of considerable size, and each bears, on its
margin, two prominences, the young otocysts. The proboscis is very long.
Three views of a larger medusa, about .5 mm. in diameter, are shown in
Pl. 45, figs. 5, 6 (from a photograph), and 7. The bell is now propor-
tionately much broader, though the gelatinous layer is still very thin.
The number of tentacles is now eight. There are two otocysts per lappet,
each connected with an otoporp (PI. 45, fig. 7). Peroniae are as yet hardly
visible. The velum is well developed; and the proboscis still long. There
is no trace of any peripheral canal system, nor are any gastric pockets as
yet developed.

The identity of this stolon with C. peregrina seems not unlikely, because in
the only other related species, Cunoctantha incisa, taken during the expedition
which lacks a canal system a single median otocyst appears first in each lap-
pet, the lateral otocysts being developed later (p. 53).

A second Cunina stolon (PI. 27, fig. 8) was taken from the stomach of a
Solmundella bitentaculata. Unfortunately this stolon, which certainly belongs to
a different species from the one just described, was not far enough advanced
for even provisional identification. The buds in this case are nearly globular
in outline and have no distinct proboscis. The tentacles, on the other hand,
appear soon after the earliest formation of the bud, and are very long in the
larger buds. In development a single tentacle first appears, and this may
reach a considerable length before the rudiment of a second appears. In
larger buds there are four, five, or six tentacles, six being the largest num-
ber observed. In one bud the bell margin is already marked as a ridge
connecting the tentacles but there are as yet no traces of otocysts.

Solmissus Haeckel, 1879.
sens. em. Maas (: 044).
Cunanthidae without peripheral canal system or otoporpae.
This genus was instituted by Haeckel (79) to include Cunina albescens de-
scribed by Gegenbaur (’56), and the two new species, S. fuberi and S. bleekii,
which he himself described (’79, pp. 350, 351). So far as I can learn, only two

64 THE MEDUSAE.

additional species have been recorded since. Fewkes (’86) has described, from the
Gulf Stream, Solmaris incisa, which certainly is not a Solmaris but belongs to
the present genus; and Agassiz and Mayer (: 02) have described, S. marshalli,
from the Pacific. ‘The members of the genus are so closely allied anatomi-
cally that we are forced to turn to such features as form of the bell, number
of tentacles, and number of otocysts, for specific characters. Of these char-
acters, probably the first, and certainly the second and third, are subject to
much individual variation. To add to the confusion, Haeckel’s account of
S. faberi and S. bleekii, are altogether insufficient, while S. incisa was described
by Fewkes from fragmentary specimens. Fortunately, the present collection
contains series of two species, S. marshalli and a second probably identical
with S. incisa, extensive enough to allow me to work out the variability of the
several characters and their probable specific value more fully than has
previously been done.

Solmissus marshalli Agassiz and Mayer.

Solmissus marshalli Agassiz and Mayer, : 02, p. 151, pl. 5, figs. 23-25.
Solmaris punctatus Mayer, : 06, p. 1133.

Plate 16, Figs. 5,6; Plate 21, Figs. 4, 6-8.

Ten specimens of this species were taken at the following stations :—

Station. Depth, fathoms. Dianicter, Panetta / oe Ree Gonads. Preservation.
|
4646 | 300 to surface | 34 13 ? ? Very fragment’y.
( 9, and 3 more |
4663 | 300 to surface | 14. tentacles in| | 3 in one None | Fragmentary.
process of >
formation
4671 | Surface 48 16 9-13 fe) Good.
4675 | Surface 35 16 (GS) a Good.
4675 | Surface 46 16 10, 9, 5 és Good.
4704 | Surface 15 11 3, 3, None | Fragmentary.
4711 | Surface 13 12 " 2) os OL None | Fair.
| 4717 | 300 to surface} 32 16 9 in one é Fair.
| (| 15, 14, 13, 12
4722 | 300 to surface | 62 16 | 14, 12, 12, 12 ad Good.
1/44) 12/11,'8, 10
4724 | 300 to surface | 28 8 ? None | Fair.
4730 | 300 to surface | 30 14. (GOs Uf a Fragmentary.

The gelatinous dise is thick and rigid; the marginal lappet zone, on the
other hand, very thin. The bell is flat, hardly if at all arched, and about
half as high as broad ; its exumbrellar surface issmooth. In life the “ collar”

region is always so much recurved that, when seen from above, the zone at

SOLMISSUS MARSHALLI. 65

which the tentacles arise seems to form the extreme margin. Seen from be-
low (Pl. 16, fig. 5) the lappet region and velum entirely conceal the gastric
pockets. The lappets are about as broad as long, square, with the margin
hardly if at all incised in the radii of the peroniae. The number of tentacles
is variable, the maximum number observed being sixteen. The specimen de-
scribed by Agassiz and Mayer had fourteen, a number found in one of the
present specimens also. The smallest number observed was eight; this,
strangely enough, was in a moderate-sized individual, 28 mm. in diameter,
(Pl. 16, fig. 6), and it appears to be the adult number in this specimen, since
there is no trace of any further development of tentacles. Rudimentary
tentacles are, however, present in small specimens. It is interesting to note
that in the development of new tentacles the new peroniae appear first, and
then the tentacles; in one specimen such a peronia is visible while the ten-
tacle has not commenced to grow. In no case was a developing tentacle
observed in a large specimen. It appears, then, that the full number of
tentacles, though not very early developed, is attained long before the
medusa attains its full size and sexual maturity. The tentacles are carried
radiating stiffly outward from the bell in life.

The number of otocysts per lappet is variable, and appears to increase con-
stantly with the growth of the medusa. The largest number observed in any
one lappet was fifteen, in the case of the largest specimen, but. it is doubtful
whether this is the maximum. This is about twice as many as are known
to occur in 8S. albescens, the greatest number recorded for one lappet of that
species, so far as I can learn, being seven. In small specimens the number
of otocysts per lappet is much smaller. Thus, in the smallest specimen,
13 mm. in diameter, there are two, three, three, and in one very narrow
lappet, evidently recently formed by the development of a new peronia and
tentacle, only one. In medium sized individuals there are usually from seven
to ten per lappet. Agassiz and Mayer (:02) were able to find only one
otocyst, on account of the poor condition of their specimen.

The sense organs themselves so closely resemble the condition described
and figured by the Hertwigs (’78) for S. a/bescens that no detailed account
is necessary here. ‘The sensory pad supporting the sense organ is large and
some at least of the spindle-shaped ectoderm cells bear bristles (Pl. 21,
figs. 4, 8). The otocyst is small in comparison with the pad, and contains
a single otolith, which is not crystalline but rounded, even in fresh specimens.

There are no otoporpae.

66 THE MEDUSAE.

The gastro-vascular system is typical of the genus, the stomach being flat,
the mouth surrounded by a simple circular lip, and usually widely opened.
The gastric pockets, which vary in breadth, are nearly square in outline.
The aboral gastric wall is evidently very delicate, for in all the specimens
it is more or less torn over the central regions of the pockets (Pl. 16, fig. 5).
When the wall is entirely torn away over the pockets, as is often the case in
battered specimens, it is seen that the convexity of the pockets is caused
by swellings or prominences of the aboral side of the gelatinous disc, com-
parable to the genital prominences which occur in the same region in the
Solmaridae (p. 86). There is no trace of either peronial or ring canals.
Neither is there any definite cell-strand which might be supposed to represent
a circular canal. Such a cell-strand has been described and figured by the
Hertwigs (78) for S. adbescens, but the only approach to such a structure
which I have been able to find in the present species is a slight crowding of
the endoderm cells (PI. 21, fig. 8).

The sexual products are located on the gastric pockets chiefly near their
margins, never, so far as I have observed, occurring on other regions of the
gastric wall. In a mature female the gonads consist of a number of oval
swellings, lying as a rule in radial folds, each swelling inclosing a single very
large egg (Pl. 21, fig. 7). Considering the very great size of the eggs (1 mm.
in length), and the thinness of the ectodermal layer which encloses them, it
seems probable that they are set free by the breaking down of the latter,
which would account for the fact that the gastric wall is so often torn in the
neighborhood where the gonads develop. In the male the sexual products
are developed more evenly over the surface of the pockets. Agassiz and
Mayer (:02) described the gonads in this species as horseshoe-shaped and
lying in the interradii, i.e. between the tentacles; but from their figures
(: 02, pl. 5, figs. 23, 24), it is evident that in their single specimen the entire
aboral gastric wall was torn away over the region of the pockets, and that
the structures they have described as gonads were, in reality, nothing more
than those portions of the wall which remain adhering in the regions of the
interradial septa which separate the pockets. This condition was seen in
several fragmentary specimens in the present collection. |

This species is entirely colorless.

Solmissus marshalli is a surface form.

The present captures, together with the ones recorded by Agassiz and
Mayer (:02) from the Marshall Islands, and by Mayer (: 06, p. 1134) from

SOLMISSUS INCISA. 67

Hawaii under the name Solmaris punctatus, show that the species is generally
distributed throughout the Tropical Pacific.

Whether S. marshalli is truly distinct from S. albescens, which it resembles
in every respect except for the considerably greater number of otocysts, or
is a geographic race of the latter, is not clear. To decide this question
requires more extensive knowledge than we now possess concerning the
constancy of the number of the otocysts, and whether or not they increase
indefinitely in number with growth, as some conditions in the present speci-
mens suggest. Although the Mediterranean species S. albescens has so long
been known, neither Gegenbaur (’56), the Hertwigs (’78), nor Haeckel (’79)
have given us any definite information on this point. Before any final deci-
sion can be reached it will be necessary to correlate the number of otocysts
with the diameter of the bell in a considerable series of specimens of S. albes-
cens. I have examined the two fragmentary specimens from the Hawaiian
Islands recorded by Mayer under the name Solmaris punctatus. They show
clearly the outlines of gastric pockets, and therefore belong not to Solmaris,
but to Solmissus, and there is nothing about them to justify separating them
from S. marshalli.

Solmissus incisa Fewkes.

Solmaris incisa Fewkes, ’86, p. 954, pl. 9.
Solmissus faberi Haeckel, ’79, p. 350.
Solmissus bleekii Haeckel, ’79, p. 551.

Plate 21, Figs. 1-3, 5.

* Diameter, Number of Otocysts
Btation. Depth, fathoms. mm. tentacles. per lappet. Remarks.
4652 | 400 to surface 68 31 Sats Broken, but the fragments to-
gether make up entire disc.
4655 | 300 to surface 75 29 aaike Fragmentary, but all the tentacles

are intact.
4657 | 300 to surface |about 50) 24 or 25 5, tatts One or two of the tentacles are

lacking.

4657 | 300 to surface 65 2 in 3 of ... | Only about three-quarters of the

the bell dise is intact.

4665 | 500 to surface 80 32 ... |In three pieces, which together
make up entire dise.

4668 | 300 to surface 80 ie ... | Very fragmentary.

4673 | 300 to surface 70 27 avai Fragmentary.

4702 | 300 to surface Jabout 100 32 ? This is the best large specimen,

4702 | 300 to surface 40 20-21 ... | Very fragmentary.

4718 | Surface 17 21 2, 3,2 |In fair condition, but stomach
much torn.

4743 | Surface 10 16, and 3 | 2inone | Fair.

more de-
veloping

68 THE MEDUSAE.

In addition to Solmissus marshalli the collection contains the eleven speci-
mens tabulated above, which I believe to be identical with the S. ineisa
of Fewkes. The disc is flat; the gelatinous substance much softer than
in S. marshalli, and not nearly so thick in proportion to its breadth. As
appears from the above table, the number of tentacles is very much greater,
the largest number observed being thirty-two, the smallest eighteen. The com-
plete number of tentacles is early attained. Thus, in the specimen only 10 mm.
in diameter there are already sixteen tentacles well developed, and three
more in early stages of development (PI. 21, figs. 2, 3). In a slightly
larger specimen, 17 mm. in diameter, there are twenty-one large tentacles,
and two more in early stages of development. Unfortunately the margins
of all the large specimens were too much damaged for me to be able to count
the otocysts. In the specimen 17 mm. in diameter there are two each in
two lappets, and in the smallest, 10 mm. in diameter, two in one lappet.
In the larger individuals, also, the number in each lappet seems to be small,
apparently not more than four or five. The otocysts themselves closely re-
semble those of S. marshalli, the supporting pads being large and somewhat
triangular, and each sense organ containing a single large rounded otolith
(Pl. 21, fig. 5).

The gastric cavity in all the specimens was much battered; enough,
however, remained in several to show that they certainly belong to Solmis-
sus, not to Solmaris. The gastric pockets were mostly torn away, but their
outlines could be traced, owing to the fact that in this species, as in
S. marshalli, the gastric wall, even in very fragmentary specimens, persists
in the regions of the septa between the pockets. The gelatinous promi-
nences causing the convexity of the pockets are particularly evident in such
individuals. No trace of any canal system was visible.

In none of the specimens could the gonads be seen, on account of their
fragmentary condition.

This species must be an exceedingly fragile one, since most of the speci-
mens seem to have undergone their injuries in the net, even when taken on
the surface. In several cases the marginal zone is split along the lines of
the peroniae, exactly as in many of the specimens from the Gulf Stream,
which Fewkes (’86, 89°) has described.

It is probable that the present specimens are identical with S. ineisa
Fewkes, He, it is true, placed this species in Solmaris on the assumption
that it had no gastric pockets, and Maas (’93) has accepted this identifica-

SOLMISSUS INCISA. 69

tion; but in all Fewkes’s specimens the gastric wall was entirely torn away,
so that since he was ignorant of the true interpretation of the subumbral
prominences which he describes on the gelatinous disc, he had no direct evi-
dence on this point. It seems to me, however, that the occurrence of eleva-
tions in the radii of the tentacles shows conclusively that gastric pockets did
exist, Inasmuch as these elevations are exactly the same structures which
occur in the regions of the gastric pockets and cause their convexities in
S. marshal. The radial furrows which Fewkes observed alternating with
the prominences occur in the present specimens also, and occupy the septal
regions between the pockets ; while the “ white structure” (89°, p. 529) which
he found lining certain of these furrows, is nothing more than a portion
of the gastric wall persisting in these regions, as I have often found it; al-
though destroyed elsewhere. It is the same structure which Agassiz and
Mayer (: 02) mistook for gonads in S. marshalli. In short, Fewkes’s specimens
showed exactly the appearance of those in the present collection in which
the subumbral gastric wall is entirely torn away. In such characters as may
be considered of specific importance the agreement between the Pacific and
Gulf Stream specimens is close. Thus, in both the number of tentacles is
large, and the maximum in each appears to be thirty-two; in both a very
large diameter, 100 mm. or more, is attained; in both the gelatinous disc is
thin, soft, and very fragile; and both show the same tendency to split along
or between the peroniae, so as to divide the marginal zone into separate
lappets. Since Fewkes was unable to distinguish the octocysts in any of his
specimens, it is very desirable that fresh specimens from the Gulf Stream
be examined, the number of octocysts being probably of specific importance
in this genus.

The status of Haeckel’s (79) two species is doubtful, since his descrip-
tions are so brief and lacking in detail that the only characters on which
we can rely are size and the number of tentacles. He has mentioned the
number of otocysts per lappet, but since each species was described from a
single alcoholic specimen, I do not believe his counts of the otocysts (he found
three per lappet in S. faberi and one per lappet in 8, dleekii) can be relied on fur-
ther than to show that in both, as in the present specimens, the number of
these organs is rather small. S. faberi is 20 mm. in diameter with twenty-four
tentacles; S. bleekii 40 mm. in diameter with thirty-two tentacles. The
differences between the two are, then, no greater than occur between dif-

ferent specimens of the present species, or of S. marshallii, and can be

70 THE MEDUSAE.

explained as the result of the individual variation which, as I have shown,
occurs in the number of tentacles, or of different stages in growth. Since
furthermore, the two were recorded from the same general region of the
South Atlantic, it is altogether probable that they are in reality identical
and show no important characters distinctive from the present series;
but until the question of the identity of S. fabert with S. ineisa can re-
ceive a final answer based on a fresh study of South Atlantic specimens, I
have thought it best to use the latter name for the present species. In
the meantime it may not be amiss to point out that Solmissus incisa will
probably be found, like Rhopalonema velatum, Aglaura hemistoma, Nausithoé
punetata, Periphylla hyacinthina, and so many other oceanic Medusae, to be of
practically universal distribution in the warmer portions of all oceans.

To make any final statement of the bathymetric range of this species
would be premature. The only specimens taken at the surface are the two
very small ones ; all the large specimens, nine in number, from eight different
stations, come from between three hundred (four hundred in one case) fath-
oms and the surface. It is probable, then, that this will prove, at least
when adult, to be an intermediate, not a surface form.

Aeginidae Gegenbaur, 1856.

sens. em. Maas (: 04", : 04°).

Narcomedusae with a precise number of antimeres and with gastric
pockets adradial, usually twice as numerous as the tentacles.
Peripheral canals may (Aegina) or may not (Solmundella) be present; so
far as known, no member of the family has otoporpae.
It is in this family that the recent classification of Maas shows the greatest
divergence from the earlier system of Haeckel (79), and the greatest Improve-
ment over it. Unlike the Cunanthidae, the genera of Aeginidae have precise,
determinate numbers of tentacles; and in this family this character is a very
constant and reliable one. It is used by Maas (: 04°, : 04°), and I believe rea-
sonably, as the chief generic distinction in the family. The number of gastric
pockets is less reliable ; for while x the adult they are always at least twice
as numerous as the tentacles, in some instances, as in Aegina, they are known
to undergo still further subdivision, so that they become four times as numer-

ous as the tentacles.

AEGINIDAE. (ol

Maas (:04*, : 04°) believes that the adradial pockets of the Aeginidae
are derived by a process of subdivision from radial pockets. But the occur-
rence in the present collection of a young specimen of Aegina with énferradial
pockets equal in number to the tentacles suggests that Haeckel (’79) may
after all have been correct in maintaining that an interradial location of the
gastric pouches is the primitive one in this family.

Recognition of the fact that the presence or absence of a canal system is
not of so much systematic importance as Haeckel supposed, and that the con-
dition of the gastric pockets, whether simple or divided, is very significant,
has lead Maas to remove from the Cunanthidae those genera with bifid
pockets which Haeckel has included in that family on account of the (sup-
posed ?) presence of peripheral canals; and to transfer them to the Aeginidae.
When this is done it appears that at least two of them are identical with
genera which Haeckel himself has classed under the latter family.

Taking the number of radial parts as the chief generic character, the
following well-defined genera may be distinguished : —

1. Four tentacles ; eight or sixteen gastric pockets

TAO 2 ee. | 6©6ACgina (Cunarcha):
2. Hight tentacles; sixteen or thirty-two gastric

pockets . Se el ae Aeginura (Cunoctona, Aeginodiscus).
3. Two tentacles; four peroniae; eight gastric

OGKCUS MMPS ay c0 icy ula thst OU EA es aes Solmundella (Aeginella).
4. Four tentacles; eight peroniae ; sixteen gastric

OCKCESMMERE DS ee a: 7). san ue oy ean 9 Ae PINOpSiS:

Solmundella and Aeginopsis are made by Vanhdéffen (: 07) the basis of a
separate family, Aeginopsidae ; but their affinities with the other Aeginidae,
in conformation of the gastric pockets and lack of otoporpae, are very close.
I have already (pp. 48, 49) discussed Vanhéffen’s disposition of the other
genera here grouped in this family.

The problematic species Cunissa polypora Haeckel, with sixteen tentacles
and thirty-two gastric pockets, would form the basis of still another genus
should it ever be demonstrated that there is any such Medusa. And it is
probable that the extraordinary genus Hydroctena of Dawydoff (: 04), if it
proves to be anything but a larval Solmundella, as is suggested by its
resemblance to the stages in the development of that genus described by
Woltereck (: 05), must find a resting place in this family.

It seems to me that the following genera and species, included provision-

ally by Maas (: 04°) among the Aeginidae, may as well be removed from this

72 THE MEDUSAE.

family at once: — Cunissa duplicata Maas, as I have already stated (p. 57),
the number of gastric pockets and presence of otoporpae in this species are
good reasons for accepting Maas’s original (’93) diagnosis of it as a Cunina
as correct. It is doubtful whether the species described by Forbes as Aegino-
dorus (Polyxenia) alderi was a craspedote at all; and it is doubtful also
whether radial parts ever occur in the combination described for Aegineta
hemispherica Gegenbaur and Aegineta octonema Haeckel (eight tentacles
alternating with eight gastric pockets); at any rate, it seems certain that
these two names were given to larval forms, whose connections with the adult
cannot be determined. Finally, Aeginorhodus rosarius Haeckel (79) must
be ciassed as a nomen nudum, since it has subsequently been rejected, as
unfounded, by Haeckel himself (’81).

Aegina Eschscholtz, 1829.

sens. em. Maas (: 04°, : 05).

(non. Aegina, Vanhéffen, : 07).

Aeginidae with four tentacles and with eight (or sixteen) gastric pockets
in the adult.

This genus, though long known, has seldom been recorded. I agree with
Maas (: 05) that the three new species instituted by Haeckel (79), A. rhodina,
A. canariensis, and A. eschscholizi, all from the Tropical Atlantic, are really but
one species, A. rhodina. Similarly, the two Pacific species described by Esch-
scholtz (’29), A. cifrea, and A. rosea, represent only a single species, A. rosea
having been based on an abnormal individual of A. citrea. The Atlantic and
Pacific forms are exceedingly close to each other; they present one of those
cases where it is difficult to decide whether it is best to regard them as distinct
species or merely as two geographic races of one species. Since, however,
the differences between the two, 7. e. lobing of the gastric pockets, number
of otocysts, and color, are constant, so far as known, I retain both names.
To these two species must now be added a third, from the present collection,
of which only a young stage was taken, and for which therefore no final
specific diagnosis can yet be made. THlaeckel’s two genera, Cunarcha and
Solmundus, each with one species, belong, according to the present classi-
fication, to Aegina. Cunarcha aeginoides is certainly an immature stage,

and since it was taken in the Canaries, and since, moreover, Haeckel’s very

AEGINA CITREA. 73

brief account agrees closely with figures given by Mayer of young Aegina
rhodina (: 04, pl. 4, fig. 28), it is safe to identify it with that species. It is
probable that the same is true of Solmundus tetralinus.

Aegina citrea Eschscholtz.

Aegina citrea Eschscholtz, ’29, p. 113, taf. 10, fig. 3; Haeckel, ’79, p. 338; Maas, : 05,
p. 71, taf. 11, fig. 72, taf. 13, figs. 79-82,
Aegina rosea Eschscholtz, ’29, p. 115, taf. 11, fig. 4; Haeckel, ’79, p. 338.

Plate 1, Fig. 5; Plate 14, Fig. 5.

Station 4663; 300 fathoms to surface ; one fragmentary specimen, 6 mm.
in diameter.

Station 4672; bottom of Tanner net, 400 fathoms; one specimen, very
fragmentary, about 15 mm. in diameter.

Station 4717; 300 fathoms to surface; one poor specimen, 12 mm. in
diameter.

Station 4719 ; 300 fathoms to surface ; one specimen, 20 mm. in diameter.
This is the specimen photographed (PI. 1, fig. 5) and from which the colored
figure (Pl. 14, fig. 5) was drawn from life.

Although I have four specimens of Aegina citrea at hand, I am not in
much better position to give a satisfactory diagnosis of the species than
was Maas (: 05). His suggestion that the secondary subdivision of the eight
main gastric pockets into sixteen minor lobes may prove to separate the
Pacific from the Atlantic species is borne out by the fact that this feature
appears in the two larger specimens in the present collection, as is shown in
the photograph (PI. 1, fig. 5). It seems probable that the number of otocysts
may likewise prove to be of specific importance. Haeckel (79) records six-
teen (four per quadrant) for 4. rhodina; and since he found the same number
in A. canariensis, which is certainly nothing but a young stage of the latter,
this number may be taken as characteristic of that species. In A. citrea, on
the other hand, Maas (: 05) could distinguish only eight ; while I find two per
lappet, in every case in which the margin is in good enough condition to
allow of counting. Maas has suggested, though without actual evidence, that
there may be secondary tentacles such as are present in Aeginura, as well as
otocysts on the margin in this genus; but I find no indications of these

structures in the present specimens.

74 THE MEDUSAE.

I am unfortunately unable to state certainly whether or not there is a canal

system, such as Maas (:05) has described from a study of sections in the
_ “Siboga” specimens.

The color of this species is characteristic and striking, stomach and pock-
ets being lemon yellow, tentacles orange or pink. This is the coloration
described by Eschscholtz.

A. citrea is one of the few species taken during the expedition in the
closing net, a specimen having been captured in the Tanner net at station
4672 from about 400 fathoms. It is widely distributed over the Pacific
(present captures and those of Eschscholtz), and was taken in the Malay

?

Archipelago by the ‘“ Siboga” expedition.

It is probable that a specimen 5.5 mm. in diameter, taken at Station 4671
from between 300 fathoms and the surface, is to be regarded as a very
young stage of A. citrea. In this individual the radial septa between the
gastric pockets are deep. The interradial notches, however, are much shal-
lower; in one quadrant there is a true septum; in two others merely very
shallow notches such as subdivide adradially the eight pockets of adult
specimens of Aegina. In the fourth quadrant there is no interradial division

at all, but only a single undivided pocket occupying an interradial position.

Aegina alternans, sp. nov.
Plate 17, Fig. 1.

Station 4649; in the trawl, 2235 fathoms to surface; 1 specimen, 40
mm. in diameter.

This very interesting specimen was in fairly good condition. The bell is
high and rounded, its surface smooth, the marginal zone broad, the per-
oniae correspondingly long, and the margin only slightly incised in their
radii (Pl. 17, fig. 1). Unfortunately the margin was too much damaged
to count the otocysts; in one quadrant I observed one, in the next apparently
two; but in the remaining two quadrants none were to be seen. The
sense organs are of the type usual among the Aeginidae, without otopor-
pae. By far the most important feature of this species is the condition of
the gastric pockets. These, as is shown in the general view (PI. 17, fig. 1)
are only four in number, interradial in position, without any trace whatever

of interradial notches; the radial notches, however, are very deep. Fortu-

SOLMUNDELLA. 75

nately the oral gastric wall is entire, so that it was very easy to follow out
the structure of the pockets on such a large specimen by probing and in-
jecting air. The central stomach is flat, the mouth large, wide open, and
the lip, if any was present, is torn off. Not wishing to destroy the single
specimen of this remarkable species, I was not able to settle definitely the
question of presence or absence of canals. Surface views, however, strongly
suggest the presence of peronial and festoon canals. There are no traces
of the development of sexual products, the gastric wall being uniformly
thin over its entire surface. The Medusa is entirely colorless. Apparently,
from. the entire absence of gonads and the number of gastric pockets, this
is an immature stage of some very large species. I refer it provisionally
to Aegina on account of the number of tentacles, though it is possible that
when the adult is known this generic identification may require revision.
The most important feature of the specimen is, of course, the fact that the
four gastric pockets though only equal in number to the tentacles are inter-
radial in position and alternate with the latter.

Solmundella Haeckel, 1879.
sens. em. Maas (: 04%, : 04°).

Aeginopsis J. Mueller, ’51; Gegenbaur, 756; etc. (non. Brandt, ’38).
Aeginella and Solmundella Haeckel, ’79.
Aeginella Mayer, :00°; Bigelow, : 04.

Aegindae with four peroniae, but with only two tentacles; with eight
gastric pouches and without canal system.

There is, since the studies of Browne (:05”) and Maas (: 05), no longer
any doubt that Haeckel’s ('79) description of a canal system in his genus
Aeginella was an error, and that Aeginella and Solmundella are, therefore,
synonyms. Since the name Aeginella is already preoccupied for a crustacean
genus, a fact which I had overlooked at the time I published my paper (: 04)
on the Medusae from the Maldives, it must be abandoned in the present con-
nection and the name Solmundella must be retained. This has already been
pointed out by Maas, : 04°.

Of the various species of this genus (Haeckel, 79, enumerates four for
his two genera, and Maas, ’93, has since added another) probably only two,

S. bitentaculata and 8. mediterranea, are valid. And even these two are so closely

76 THE MEDUSAE.

related to each other that, although the evidence at present indicates
that they are distinct, we must recognize the possibility that further
research may prove that they are really only two varieties of a single species.
Among the differences between them which Maas (: 06°, : 06°) enumerates, are
size, color, stage of development at which the gonads appear, and number
of otocysts. It seems to me that the last of these is of much the greatest
systematic importance. No doubt S. bitentaculata is larger than S. mediterranea,
and as a rule more highly colored, but both size and color are well known
to be variable characters among Hydromedusae, and to be dependent largely
on the food supply of the specimens in question. The question of the time
of appearance of the gonads is likewise an unsafe criterion, because it is
very variable, for it has been conclusively shown by Browne (: 05°) that
even very small specimens of S. ditentaculata (size unfortunately not given)
possess gonads on the gastric pouches, although it is only large specimens
(9 mm. in diameter) which have them developed on the central portion of
the stomach ; and Maas himself has stated that, while some specimens 8 mm.
in diameter have no gonads at all (:05, p. 75), others of the same size are
sexually mature (: 06°, p. 99).

The question of the number of otocysts seems to me much more impor-
tant. In the case of S. mediterranea we have the positive statement of the
brothers Hertwig (78) that there are never more than eight otocysts, two
to each quadrant. In S. bitentaculata, however, Maas (: 05) has found as many
as thirty-two of these organs in large specimens. Furthermore, not only is
the number in /S. mediterranea strictly determinate, but the total number is very
early attained, while there is reason to believe that in S. bitentaculata, on the
contrary, the number increases constantly with growth, as noted by both
Browne (: 05°) and Maas (: 05, : 06°). It is important also to note that the
number of sense organs does not increase with equal rapidity in all quadrants
of the margin, a phenomenon I am able to trace in the present specimens.

The identity, with one or the other of these two species, of the various
specimens described by Haeckel (79) and Mayer (: 00°) under the name
S. dissonema is not easy to settle; but inasmuch as all these specimens agree
in having only eight otocysts whatever their size, and since all are of com-
paratively small size, the largest, from the Canaries, being only 8 mm. in di-
ameter (Haeckel, 79), and may become sexually mature when only 3 mm. in
diameter (Mayer, :00°), it is probable that they really belong to S. mediterranea,
not to S. bitentaculata. The same is true also of Aeginella miilleri Haeckel, which

SOLMUNDELLA BITENTACULATA 77

is certainly only a younger stage of his A. dissonema, at the type locality of
which species it was taken. Aeginella dissonema Bigelow (:04) from the
Maldive Islands, is, however, a synonym of A. bitentaculata.

Solmundella mediterranea has been recorded under its own name not only
from the Mediterranean and from the Tropical Atlantic (Maas, 92), but from
the Antarctic Ocean as well (Maas, : 06°); and since Agassiz and Mayer's
record of S. dissonema from the Fiji Islands probably belongs to S. mediterranea
its range apparently extends to the Pacific. S. bitentaculata seems to have an
almost parallel distribution, since it has been found in the Atlantic (Maas,
93, Solmundella henseni), in the Indian Ocean (Browne, : 04, : 05°; Bigelow,
:04), in the Malay Archipelago (Quoy et Gaimard, ’33; Maas, : 05, : 06°),
and in the Tropical Pacific by the present expedition of the “Albatross.”

Solmundella bitentaculata Quoy et Gaimard.

Charybdea bitentaculata Quoy et Gaimard, ’33, p. 295, taf. 25, figs. 4, d.

Solmundella bitentaculata Browne, : 04, p. 741, pl. 56, fig. 3, : 05°, p. 153, pl. 4, figs. 7-6;
Maas, : 05, p. 73, taf. 11, fig. 74, taf. 12, fig. 75, taf. 13, figs. 86-89.

Aeginella bitentaculata Haeckel, ’79, p. 541.

Aeginella dissonema Bigelow, : (4, p. 261.

Campanella capitulum de Blainville, ’34, p. 286; L. Agassiz, 62, p. 169.

Solmundella henseni Maas, 793, p. 55, taf. 5, fig. 17.

Plate 2, Fig. 3.

Station. Depth, fathoms. einer seat eel Remarks.

4583 | 300 to surface 1.5 2 in each 1 good specimen. —

4587 | 300 to surface 3.5 | 38,2,otherstoo | This is the specimen photographed,
torn to count. Plate 2, fig. 3.

4588 Surface 1.5 2, 2, 2, 2

4588 Surface 2.5 4, 2, 2, 2 Many specimens 1.5 to 3 mm. in diam-

eter were taken at this station.

4588 Surface 3 ?

4640 Surface 2 ? 1 fragmentary specimen. —

4644 Surface 3 4 in one 2 rather fragmentary specimens.

4655 Surface 1.5 2 in one 1 fragmentary individual.

4671 Surface 1 2, 2, 2, 2 Good specimen.

4671 Surface 2.5 Aes Several specimens of this size.

4680 Surface 1-1.5 2 very fragmentary specimens.

4713 | 300 to surface 4 ? Margin torn off the single specimen.

4716 Surface 3 4, 4, 4 1 fair specimen.

4735 Surface 2.5 V4 Very fragmentary.

78 THE MEDUSAE.

This widely distributed species was taken at eleven stations. All the spe-
cimens are small or medium sized. Unfortunately many of the specimens
were so battered that it was impossible to count the otocysts, but this could
usually be done in one or more quadrants. In the smaller specimens the
number per quadrant is two, eight in all. In larger specimens there are
three or four per quadrant, as Maas (:06°) and Browne (: 05°) have already
observed. The increase is, however, irregular, there being often different
numbers in the different quadrants of a single specimen, as is seen in several

cases in the above table.

Aeginura Haeckel, 1879.
sens. em. Maas (: 4°, : 05).

Cunoctona Haeckel (’79).
Aeginodiscus Haeckel (’79).

Aeginidae with eight tentacles and sixteen (or thirty-two) gastric pockets ;
with secondary tentacles situated on the margins of the lappets.

This interesting genus of Narcomedusae, since its discovery, has been
described twice by Maas, from the collections of the Prince of Monaco (: 04°)
and from those of the “Siboga” expedition (: 05). Maas has been able
to study the anatomy in such detail that I can add but little to his account
from the rather fragmentary specimens in the present collection. The most
interesting feature of this genus is the presence, demonstrated by Maas (: 05)
on the “Siboga” specimens, of a series of secondary tentacles (three per
lappet) on the bell margin. These are solid, with endoderm core, and are
connected with the vascular lamella (: 05, p. 79). They are not known to
occur normally in any other Narcomedusa, but I have found that such a
secondary tentacle may sporadically replace an otocyst in Pegantha smar-
agdina (p. 91), evidence supporting the essential identity of otocysts and
tentacles in this group. Otocysts are also present. Specific diagnosis of
the members of the genus is uncertain, because the specimens both of the
“ Challenger” and of the Prince of Monaco were rather fragmentary. There
seems no doubt that the surface form, A. /anzerotae Haeckel, is distinct from
the two or three intermediate species, since it differs from the latter in the
form of the stomach, presence of a proboscis, and especially in lacking
the very characteristic endodermal pigmentation. Moreover, it is doubtful
whether it has the secondary tentacles on the bell margin, for Haeckel saw

no such structures, although he studied living specimens (’79, p. 318).

_-_

AEGINURA. 79

The differences between the three intermediate forms, A. myosura Haeckel,
A. grimaldii Maas, and A. weberi Maas, are more doubtful, inasmuch as the first
two, at least, were described from such fragmentary specimens that Maas
(: 04°) himself admits the possibility that some of the apparent differences
may be due to imperfect preservation. A. myosura, according to Haeckel’s
(81) account, appears to differ from the other two species in having eight of
the gastric pockets large and eight small, and he makes no mention of the
pigmentation, a character so striking and so permanent even in alcoholic
specimens that it could hardly have escaped him. His failure to mention
secondary tentacles cannot, however, be construed as indicating their absence,
on account of the condition of his material.

Maas (: 05) cites as taxonomic characters separating A. grimaldii from A.
weberi, size, arrangement of the gonads, and presence or absence of a periph-
eral canal system. It seems to me, however, that in the present case none of
these are very significant. According to Maas (: 05) A. weberi is 35-45 mm. in
diameter ; A. grimaldii only 12 mm; but his figure from the fresh specimen of
the latter, said to be life-size (: 04°, pl. 3, fig. 19), measures 23.5 mm. in
diameter. This discrepancy may perhaps be explained by the fact that the
“Monaco ” specimens were preserved with osmic acid, which almost invariably
shrinks Medusae considerably. Furthermore, there is no evidence to show that
even 23.5 mm. is the largest size attained by A. grimaldit.

The gonads in A. grimaldii, of which a female only was observed, are
described as consisting of large eggs, irregularly scattered over the gastric
pockets, whereas in A. weberi (male), as in A. myoswra (likewise male), the
sexual products are evenly distributed, but there is good reason to believe
that this is a sexual, not a specific difference, inasmuch as the two sexes
of Solmissus marshalli exhibit precisely the same divergence.

The question of canals, said by Maas to be absent in A. grimaldii (: 04°,
p. 40) but present in A. weber? (: 05, p. 78), is less easily settled. His con-
elusion for A. grimaldii seems to be supported by good evidence, afforded
by the study of sections, but the occurrence of true canals in A. weberi
is more doubtful. According to his account, gained from sections of the
margin, the canal system is so nearly obliterated that no definite endothelial
layer is to be found, although there is an open lumen. His chief reason
for considering this lumen as normal and not an artifact, is its regular
occurrence (: 05, p. 79), but as the second possibility still exists,

it seems to me unwise to lay much stress on this supposed character

80 THE MEDUSAE.

until it has been more fully tested on more extensive and better preserved
material.

Whatever decision may eventually be reached as to the relationship of
these two species, the specimens in the present collection resemble Maas’s
figures of A. grimaldii so closely that they are best referred to that species.

Aeginura grimaldii Maas.

Aeginura grimaldii Maas, : 04°, p. 38, pl. 3, figs. 79-28.
? Aeginura weberi Maas, : 05, pp. 77, taf. 11, fig. 73, taf. 12, fig. 76, taf. 14, figs. 90-99.

Plate 9, Fig. 4.

Station 4646 ; 300 fathoms to surface ; 1 specimen, 21 mm. in diameter, ?.

Station 4655; 300 fathoms to surface; 1 specimen, 20 mm. in diameter,
sex? Very fragmentary.

Station 4669 ; 300 fathoms to surface; 1 specimen, 13 mm. in diameter.

Station 4676; 300 fathoms to surface ; 1 specimen, 16 mm. in diameter.
Fragmentary.

All these specimens agree closely with Maas’s (: 04°) description of A.
grimaldii. In only one specimen, a female, can the sex be determined
from a surface view. In this individual (Pl. 9, fig. 4) the eggs are very
large and irregularly distributed over the surface of the gastric pockets.
Another specimen, 13 mm, in diameter, appears from a surface view to be
a male, and in it the oral wall of the gastric pockets is uniformly thickened.
Apparently, then, here, as in Sodmissus marshalli, the different arrangement _
of the genital products which Maas (: 05) believed to be of systematic im-
portance is only a sexual difference. Unfortunately the margins of all the
specimens are so much damaged that I can give no detailed account of the
marginal organs, though it appears that im each octant there are three
structures of considerable size, corresponding to the secondary tentacles
described by Maas (:-05) for A. webert; also in one specimen I found a single
otocyst, too fragmentary for any accurate description. No other marginal
organ was visible in that particular octant, so that I can say nothing as to
relative positions of secondary tentacles and otocysts; probably, however,
they agree with Maas’s description of A. weberi.

Gastro-vascular system. —I was unable, on surface views, to demonstrate
the presence of any canal system, but the margins of all the specimens were

too fragmentary to settle this question definitely. The interradial incisions

SOLMARIDAE. 81

between the gastric pockets are deeper than the incisions in the radii of the
tentacles, just as Maas has figured them ; a feature suggesting that the former
are more primitive than the latter.

Color.— The pigmentation of this species (PI. 9, fig. 4) is one of its most
characteristic features; it closely resembles the figures given by Maas of
A. grimaldii and of A. weberi. As in those species, it is entirely confined to the
endoderm. The central stomach and gastric pockets are deep chocolate red,
which is almost black after preservation. The large eggs appear white,
apparently because they are so opaque as to hide the heavily pigmented
endoderm. The marginal zone is of a pale reddish tint.

It appears that, like other intermediate Medusae, this is a widely dis-
tributed species, having been taken in the Atlantic and in the Eastern
Tropical Pacific.

Solmaridae Haeckel, 1879.

sens. em.

Narcomedusae without gastric pockets, the genital products being devel-
oped, either as thickenings or diverticula in the oral wall of the central
stomach ; with or without peripheral canals and otoporpae.

As modified above, this family includes the Solmaridae and Peganthidae
of Haeckel, which were separated by the presence or absence of a canal
system ; a feature I believe to be of but slight systematic importance. This
character does, however, seem to be at least of generic value in this group
(even if not in the Cunanthidae) ; and it, together with presence or absence
of otoporpae, separates the family into two subfamilies, one with, the other
without, canals and otoporpae. These two subfamilies, the former corre-
sponding to the Peganthidae, the latter to the Solmaridae of Haeckel, bear
to each other much the same relation as do the two subdivisions of the
Cunanthidae, 7. e. on one hand Cunina and Cunoctantha with canal system
and otoporpae, and on the other Solmissus without canals or otoporpae.

Under the first of these subdivisions (Peganthidae) Haeckel (’79) has
distinguished four genera, viz., Polycolpa, Polyxenia, Pegasia, and Pegantha,
distinguishing between them by differences in the conformation of the gonads.
The distinctions between these genera are so slight, even if not due, in
part at least, to different stages in the growth of the gonads, that it seems
to me very doubtful whether all of them are valid. Thus Polycolpa, with a

simple ring-like gonad, is probably nothing more than an early stage in the

82 THE MEDUSAE.

development of Polyxenia, in which the gonads form, in addition to the ring,
interradial diverticula, as in Pegantha. Polyxenia presents a very puzzling
case of nomenclature, since it has been used in different senses by various
writers. Eschscholtz, who established the genus for P. cyanostylus, makes
no reference in his notice to a canal system or to marginal sense organs, thus
failing to mention the only characters which would help us to locate the
species in the family. So far as the gonads are concerned (Eschscholtz, ’29,
taf. 10, fig. 1), it might equally well belong to Solmoneta. The same is
likewise true of the Medusa mollicina of Forskal, since the original figures of
Forskal (1776, p. 109; tab. 33, fig. c) resemble in the form of the gonads
the well-known Solmoneta flavescens of the Mediterranean. oveolia diadema
Péron et Le Sueur and P. cyanogramma Quoy et Gaimard are based on
even less recognizable notices. Therefore there is good room to doubt
whether Haeckel’s identification of these early names, with specimens which
he himself observed, was of much value. Haeckel has described one new
species of Polyxenia, P. cyanolina, but very briefly and without figures.
Previous to Haeckel’s work the name Polyxenia had been used in a very
different sense by Forbes (’48), who applied it to P. alderi, a form probably
not a craspedote Medusa at all; and by Metschnikoff (’74), who has described
under the name Polyxenia leucostyla Will, specimens probably identical,
generically at least, with the long-known Solmoneta flavescens Kolliker.

In view of the fact that the type species of Polyxenia (P. cyanostyla Esch-
scholtz), is unrecognizable generically, and to avoid further confusion, it
seems best to abandon the name Polyxenia altogether. If this be
done, Polycolpa, which is probably not distinguishable generically from
Polyxenia, might well be retained.

Pegasia has, it seems to me, a better claim to generic standing, if any
specimens normally exhibit the conformation of the gonads described by
Haeckel (’79). The only one of the four genera of which a satisfactory
account has appeared is Pegantha.

Vanhiffen (: 07), abandoning the conformation of the gonads as a taxo-
nomic character in this family, makes the number of tentacles the chief
generic character, distinguishing Pegantha with 10-13, Polyxenia with
16-18, and Polycolpa with 25-30 tentacles. The series in the present
collection show that this character is so variable that such slight differences
cannot be considered of much importance ; for, according to this scheme,

some specimens of Pegantha triloba would belong to Pegantha, others (p. 87),

PEGANTHA MARTAGON. 83

to Polyxenia; while of four specimens of P. laevis two would fall in
Polyxenia, and two would be intermediate between that genus and
Polycolpa. For this reason it seems better to neglect this character
entirely as the basis of generic diagnosis, and to follow Haeckel in including
in Pegantha all species in which the gonads are restricted to the marginal
region of the gastric wall, and localized in interradial pouches.

Pegantha Haeckel, 1879.

Solmaridae with canal system and otoporpae ; the gonads forming diver-
ticula of the margin of the oral gastric wall. 8-32 tentacles.

This genus, since first described by Haeckel (79), has been recorded by
Fewkes (’89*) from the Gulf Stream; Maas (93) from the Tropical Atlantic ;
Bigelow (: 04) from the Indian Ocean; and by Mayer (: 06), under the name
Solmaris insculpta, from the Hawaiian Islands. It is now well known ana-
tomically from the studies of Maas and Haeckel, but up to the present time
no early stages in its development have been observed. Therefore I am
fortunate in being able to trace in detail in a new species, P. smaragdina,
a form of parasitic development from the egg, very closely resembling that
known to occur in Cunina proboscidea (Metschnikoff ’86*, Stchelkanowzew : 06),
and in demonstrating the occurrence of internal budding in a second species,
P. laevis.

The distinctions between the various described species of the genus, as is
so often the case with oceanic Medusae, are by no means clear. The diffi-
culty is caused chiefly by the unsatisfactory nature of Haeckel’s original
descriptions, and by the fact that he based his various species chiefly on
differences in the conformation of the gonads, a feature which may change
with growth.

The present collection contains four easily distinguishable species. Two
of these can be referred to P. martagon Haeckel and to P. triloba Haeckel. The
other two differ so markedly from any species as yet known that they are
described as new.

Pegantha martagon Haeckel.

Pegantha martagon Haeckel, ’79, p. 332.
Pegantha simplex Bigelow, : 04, p. 260, pl. 5, figs. 79, 20.
Plate 18, Figs. 1-8.
Station 4634; 300 fathoms to surface ; 1 large specimen ; good condition.
Station 4637; 300 fathoms to surface ; 1 large specimen ; good condition.

84 THE MEDUSAE.

Station 4646 ; 300 fathoms to surface ; 2 small fragmentary specimens.
Station 4650; 300 fathoms to surface; 2 large specimens; fair condition.
Station 4652; 100 fathoms to surface ; 4 large specimens ; fair condition.
Station 4654; 300 fathoms to surface; 2 large specimens; good condition.
Station 4661; 300 fathoms to surface; 1 fragmentary specimen.

Station 4663 ; 300 fathoms to surface; 2 small fragmentary specimens.
Station 4667; 800 fathoms to surface; 1 good specimen.

Station 4668; 300 fathoms to surface; 1 specimen; good condition.
Station 4671; surface; 1 large specimen ; perfect.

Station 4673 ; surface; 2 specimens ; fair condition.

Station 4708 ; surface ; 2 small specimens.

Station 4717; 200 fathoms to surface ; 1 fragmentary specimen.

Station 4719; 300 fathoms to surface; 1 specimen; good condition.
Station 4723 ; surface; 4 small specimens.

Station 4725 ; surface; 1 small specimen; fragmentary.

The dimensions and the numbers of marginal lappets and tentacles of
a series of specimens, including the largest and smallest taken, are given
in the following table :—

Station. Diameter. Height. Tappete end!
mm. mm.
4663 5 3 9
4646 i) 4 12
4667 11 8 10
4659 13 8 ata
4671 5) 10 10
4659 14 T 13
4719 14 6 13
4650 15 9 11
4650 16 10 9
4668 16 9 ala
4637 20 10 12

It is fortunate that I was able to study living specimens of this species,
inasmuch as, for some reason or other, they were very difficult to preserve,
and at the time of writing, after a lapse of only two years, already show
marked signs of deterioration. The bell is rounded; the gelatinous sub-
stance thick (PI. 18, fig. 7) and considerably higher than Haeckel (’79) has
stated ; but since his description was taken from alcoholic specimens, this

difference cannot be considered of importance. Moreover, the proportion —

-—

PEGANTHA MARTAGON. 85

between diameter and height varies, and in life was constantly changing,
with changes in the state of contraction of the Medusae. Above the line
of insertion of the tentacles the surface of the bell is smooth, showing
neither nematocyst warts nor radial ridges. Sculpture is, however, present
on the marginal lappets, there being a slightly marked ridge in the median
line of each lappet, and fainter ones in the lines of the otoporpae, all being
much less prominent in this species than in P. ¢riloba. The marginal lappets
are ovate in outline, rather longer than broad, the incisions between them
deep, and the peroniae correspondingly short (Pl. 18, fig. 4). In adults the
peroniae are covered by the gelatinous substance of the adjacent marginal
lobes.

The number of lappets and tentacles is variable, as is usual in Pegantha,
the largest number observed being thirteen, in a specimen 14 mm. in
diameter, the smallest nine, in specimens 5 and 16 mm. in diameter. In
one small specimen, 9 mm. in diameter, from Station 4646, in which the
gonads have not yet appeared, one of the twelve tentacles is much smaller,
and evidently of more recent formation, than the others (Pl. 18, fig. 4); but
in large specimens in which the gonads are formed I have not found any
trace of the development of interstitial tentacles. It appears, then, that the
full number of tentacles in this species is early attained and does not con-
tinue to increase with growth. The tentacles are of the usual narcome-
dusan type, about as long as the bell diameter, and in life carried trailing,
or recurved into the bell cavity. The only feature in which the present
specimens differ markedly from Haeckel’s description is in the number of
octocysts. Haeckel (’79, p. 332) states that there are from thirteen to
fifteen of these organs on each marginal lappet, but the greatest number
which I have found in any lappet is nine, while most lappets have only
from six to eight. It is, however, questionable whether Haeckel’s counts
of the octocysts are reliable, since he states that his description of this
species was taken from strongly contracted alcoholic specimens; and I find
from my own experience that it is almost impossible to count these organs
on such material. Even if such a difference does exist in different groups
of individuals, it does not seem to me of much systematic importance,
because the number of octocysts increases with growth, and is variable in
the different lappets of any one individual. | Renewed examination of the
specimens from the Maldives has convinced me that the number of octocysts
which I recorded for them, twenty-five per lappet, was an error, being

86 THE MEDUSAE.

an error due to the contracted condition of the preserved

much too large,
material. The sense organs themselves (Pl. 18, fig. 7) are of the usual type,
each containing two or three otoliths. They are situated on “auditory
pads”; thickenings of the nerve ring, consisting of spindle-shaped ectoderm
cells some at least of which bear bristles, though most of the latter are
destroyed by preservation; and, as in all members of this genus, each
octocyst is connected with a long otoporp containing nematocysts (Pl. 18,
fig. 7, op.). At their distal ends these structures are bounded by cap-like
series of columnar ectoderm cells.

Gastro-vascular system.— The stomach is: flat, its ventral wall without any
trace of such folds or ridges as Haeckel (81) has figured for P. pantheon.
Indeed, I doubt whether such a conformation is anything more than the
result of alcoholic contraction. The mouth is surrounded by a simple and
very distensible lip. In life it is often opened so wide as to occupy half the
area of the stomach, or again contracted, as in Pl. 18, fig. 2. There are
no traces of gastric pockets (Pl. 18, fig. 4). The canal system is typical of the
genus, both peronial and ring canals being well developed (Pl. 18, fig. 4).

Gonads. — Since the conformation of these structures has been used by
both Haeckel (’79,’81) and Maas (’93) as a specific criterion in Pegantha, it
is fortunate that I can describe them from life. Haeckel (’79) describes them
in P. martagon as neither folded nor incised, but while this is true for
young specimens in which they are simple sac-like structures (Pl. 18, fig. 5),
in larger ones they are more or less lobed and irregular (Pl. 18, fig. 6), though
never definitely and regularly subdivided as in P. biloba and in P. dactyletra
(Maas, ’93). There is one important structural feature of the gonads in
this, as well as in the other species of the genus which I have examined,
mentioned neither by Haeckel nor Maas probably because of the methods of
preservation of their specimens. This is that the gonad is not a sac with
large open cavity, but is supported, and its convexity chiefly caused, by a
rounded prominence of the gelatinous substance of the disc (PI. 18, fig. 8,
g. pn.), just such as is present in the corresponding location in Sodmissus
marshalli and in S. incisa (p. 68). These prominences are absent in young
specimens and appear, in both sexes, only with the formation of the gonads.
They do not extend into the subdivisions of the gonads, but occupy their
central regions only.

This species is colorless ; the bell hyaline, the endodermal structures opaque.

Pegantha martagon is widespread, having been taken in the Indian Ocean

PEGANTHA TRILOBA. 87

(Bigelow, : 04), in the China Sea (Haeckel, ’79), and very generally through-
out the course of the “ Albatross” in the Eastern Pacific. It is probably a
surface form.

Pegantha triloba Haeckel.

Pegantha triloba Haeckel, ’79, p. 333, taf. 19. figs. 4-7.
Solmaris insculpta Mayer, : 06, p. 1140, pl. 3, figs. 8, 9.
? Pegantha quadriloba Haeckel, 779, p. 333.

Plate 14, Fig. 3; Plate 16, Fig. 3; Plate 20, Figs. 1-3; Plate 45, Figs. 1, 2.

Station. Depth. Diameter. Height. Tentacles.

mm mm. %
4650 300 fathoms to surface 22 12 12 1 excellent specimen.
4661 300 fathoms to surface 5 3 12 1 good specimen.
4712 UREACORar er. alg 6 12 1 excellent specimen.
4733 Surface . : 2.5 1 ia 1 good specimen.

I have been able to settle the identity of Mayer’s species, Solmaris insculpta,
by a study of the original specimens from the Hawaiian Islands, kindly
entrusted to me by the United States National Museum. The presence of a
well-developed and very obvious canal system and of long otoporpae shows
beyond doubt that they are typical specimens of Pegantha, not of Solmaris
as Mayer supposed. Specifically they are indistinguishable from the speci-
mens in the present collection.

The largest specimen in the present collection is about 22 mm. in diameter
by 12 mm. high; approximately the dimensions given by Haeckel (20-
25 mm. in diameter, 7-8 mm. high). The gelatinous substance is extremely
rigid, and the exumbrella bears a well-marked and characteristic sculpture
(Pl. 14, fig. 3; Pl. 16, fig. 3). From the base of each tentacle a deep furrow runs
nearly to the apex of the bell; on either side of these furrows there are ridges
which extend down to the margin of the lappets; in the middle lines of the
lappets, and also extending to the apex, are a second series of ridges; and
finally there are less prominent ridges confined to the lappets along the lines
of the otoporpae. This sculpture, very constant in all the specimens both
Eastern Pacific and Hawaiian, agrees with Haeckel’s account. It is already
developed in a specimen only 2.5 mm. in diameter (PI. 16, fig. 3). The mar-
ginal lappets are ovate, pointed, rather longer than broad; the incisions
between them deep. Three of the four specimens, ranging in diameter from

5 to 22 mm., have twelve lappets and tentacles; one, the smallest 2.5 mm.

88 THE MEDUSAE.

in diameter, has seven (PI. 16, fig. 3). Of the Hawaiian specimens, several
have twelve, thirteen, and fourteen each, and one sixteen. The tentacles, of
the usual structure, are about as long as the diameter of the bell, stiff, and
in life carried recurved into the bell cavity. There are no such nematocyst
pads at their bases as Haeckel (’81) has figured for P. pantheon.

In the largest specimen there are from eighteen to twenty otocysts per
lappet (Pl. 45, fig. 7), the same number that Haeckel records. Mayer (: 06)
observed only three per lappet; but I find that his large Hawaiian speci-
mens also have about eighteen to twenty. In the smallest specimen there
are only four or five per lappet (Pl. 16, fig. 3). In a slightly larger one,
5 mm. in diameter, five was the largest number counted in any lappet; but
in a specimen 11 mm. in diameter there are from seven to nine per lappet.

The octocysts themselves are of the usual type, containing two or three
otoliths and situated on ectodermic pads (PI. 20, fig. 3). The otoporpae
vary in length, the lateral ones, reaching to about the level of the bases of
the tentacles, being longest ; they anastomose somewhat; those of one lappet
are shown in Pl. 45, fig. 7. They are not bounded by definite caps of ectoderm
cells, as is the case in P. martagon (p. 86), but grow narrower and narrower,
until finally they become indistinguishable. They seem to have been over-
looked entirely by Mayer.

Gastro-vascular system.—The mouth in all the specimens is widely
opened; there is no trace of proboscis. The canal system is well devel-
oped and unusually prominent. In a small specimen 5 mm. in diameter the
endoderm layer is thickened along the proximal face of the ring canal
(Pl. 20, fig. 7), forming a ridge, variously folded, running lengthwise of the
canal. In the adult specimen there is no trace of this structure, the endo-
dermic lining of the canal being of uniform thickness throughout.

Gonads. — These, in all the large specimens, are definitely three-lobed ;
each consisting of a central and two lateral lobes (Pl. 20, fig. 2). In the
largest specimen the central lobe is rounded and supported by a prominent
gelatinous eminence (Pl. 45, fig. 2, g. pr.), while the lateral lobes, which are
the chief sexual portions of the gonads, are flat, leaf-like, and variously
subdivided. There is considerable variation in the conformation of these
organs in large specimens, though all agree in having them definitely
three-lobed. In the largest Hawaiian specimen, which is in a rather more
advanced state, the three lobes are of about equal size, sausage-shaped,

the lateral ones being only wavy in outline, not definitely subdivided, while

PEGANTHA TRILOBA. 89

the genital prominence is much smaller than in the individual just described.
In another specimen from the same collection however, the lateral lobes show
a considerable amount of secondary lobing. In specimens about 12 mm. in
diameter (of which the Hawaiian collection contains several) the gonads are
very small; each, however, already consists of three distinct lobes. Mayer’s
figure (: 06, pl. 3, fig. 8) is incorrect in that it represents the gonads as lying
at about the mid zone of the stomach surface. In reality they are at its
margin and hang into the lappet cavities, in the Hawaiian as well as in
the Eastern Pacific specimens. Our small specimens show no trace of
gonads.

This conformation of the gonads agrees with Haeckel’s ('79) account in
its main feature, 7. e. the three-lobed condition; it differs, however, in that
Haeckel described and figured the lobes of the gonad as rounded, smooth,
and without subdivisions; but since his account was taken from alcoholic
specimens it is doubtful whether it represents the normal aspect of the
organ.

Color. — The entire Medusa (adult) is of a delicate violet pink (Pl. 14,
fig. 3), the endodermal system being more deeply tinted and more opaque
than the remainder of the bell. ‘The distal portions of the exumbral ridges
and the otoporpae are deep purple. These purple exumbral lines were
observed by Mayer /: 06, p. 1140), but he failed to realize their connection
with otoporpae.

There seems to be no doubt as to the identity of this form with P. triloba
Haeckel, the only divergence from Haeckel’s account, apart from a slightly
greater number of tentacles in some specimens, being that in the present
series the lateral lobes of the gonads may be secondarily lobed. This differ-
ence, however, cannot be of specific significance, in view of the fact that
gonads of different individuals vary widely in this respect, even, indeed, to
the extent of lacking the secondary lobing altogether, as is the case in
one of the Hawaiian specimens. I have been able to examine a specimen
collected by the ‘“‘ Hassler” expedition at Rio Janeiro, which in number of
otocysts, sculpture, etc., so closely agrees with the * Albatross” and Hawaiian
specimens that I have no doubt of their identity. In the “ Hassler” specimen
however, while most of the gonads have three lobes, one has four. It is
this fact which has made me discard the character, three or four lobes, as
a specific one and to class P. quadriloba as a synonym of P. triloba. The
same conclusion might be reached, perhaps, in the case of P. biloba Haeckel,

90 THE MEDUSAE.

were it not for the facts that in P. ¢riloba the gonads are three-lobed from their
first appearance, and that I have not been able to find a gonad with less
than three lobes.

The occurrence of a specimen from the Atlantic shows that Pegantha triloba is
a species of extremely wide distribution. It is of general occurrence through-
out the Eastern Tropical Pacific, both north and south of the equator, and has
been taken in the Indian Ocean (Zanzibar, Haeckel), and in the Tropical
Atlantic, near the island of Ascension (Haeckel, P. quadriloba) and off Rio
Janeiro (“ Hassler” expedition). It is undoubtedly a surface form, since all

the Hawaiian specimens were taken on the surface (Mayer, : 06, p. 1140).

Pegantha smaragdina, sp. nov.
Plate 14, Figs. 1,2; Plate 19, Figs. 1-9; Plates 22-26.

Station. Depth. Diameter. Tentacles. Gonads.

mm.
4663 Surface TT 34 & 1 perfect specimen. Type.
4671 Surface 50 28 None 1 perfect specimen.

Both specimens of this very striking and easily distinguishable species
were alive when taken.

The bell is very low, only about one fifth as high as broad, and in its flat
outline much resembles Solmissus, differing correspondingly from other species
of Pegantha (PI. 14, fig. 2). The aboral surface is entirely without sculp-
ture, and even the otoporpae are so flat that they can hardly be said to form
ridges. The lappets are quadrate, about as long as broad; the incisions
between them so shallow that the peroniae are almost as long as the lap-
pets (Pl. 19, fig. 5).

Tentacles. — There are thirty-four tentacles and lappets in the larger
specimen. ‘Three of the tentacles are much smaller and evidently of more
recent growth than the others, but they are already associated with well-
developed peronial canals, and bear the same spacial relations to the adjacent
gonads as do the larger tentacles. In life, when the animal is idly floating,
the tentacles are carried projecting stiffly outward from all sides of the bell,
a feature heightening its Solmissus-like appearance.

Otocysts. — There are usually six, sometimes seven or eight otocysts per
lappet ; thus in the largest specimen a total of about two hundred. The
sense organs themselves are of the usual type, containing from three to five
otoliths (Pl. 19, figs. 3, 8). They stand on well-marked pads consisting, as

PEGANTHA SMARAGDINA. 91

is seen in a radial section (PI. 19, fig. 8), of thickly crowded spindle-shaped
ectoderm cells, some at least of which bear bristles in life. In one instance
an otocyst is replaced by a small tentacle (PI. 19, fig. 1), —a structure differ-
ing in no way, except for its small size and rudimentary condition, from any
normal tentacle, but connected at its base with an otoporp. This replace-
ment of an otocyst by a tentacle is evidence of the close relationship between
these two classes of structures among the Narcomedusae. The otoporpae
(Pl. 19, fig. 3), though less prominent than in other species of Pegantha,
are of the usual structure, consisting of densely crowded ectodermal cells
enclosing nematocysts ; they extend about half the length of the marginal
lappets (Pl. 19, fig. 5).

Gastro-vascular system. — The stomach is flat, its outline circular in the
smaller specimen, in which no gonads have appeared (PI. 19, fig. 5). The
mouth, which is widely open, is surrounded by a simple circular lip (PI. 14,
fig. 1). The fact that the oral wall of the stomach is thin and but poorly
supplied with musculature makes it doubtful whether the mouth is ever
closed. The canals, both peronial and circular, are so broad that they easily
admit of the entrance of a stout probe. In the smaller specimen the ring
canal in several of the lappets shows a triangular centripetal process suggest-
ing the future formation of a new pair of peronial canals.

Gonads. — These are simple in this species, each consisting merely of a
rounded swelling without lobes or processes, the only subdivisions being an
occasional shallow furrow or notch (PI. 19, fig. 2). In one instance, however,
it seems that a previously existing gonad has been secondarily divided into
two, with the formation of a new tentacle and peronia. In the one speci-
men, a2 male, in which gonads are present, the sexual products are nearly
mature, so that it appears that this conformation represents the adult condi-
tion in this species. As in other members of the genus, the gonads are
supported by gelatinous prominences, which, though large in the adult
specimen, do not appear until the gonads develop (compare PI. 19, fig.
7 with fig. 9).

Color. — One of the most striking features of this species is its color, the
stomach, canals, and gonads being of a deep, opaque, lemon yellow, as is shown
in the sketches from life reproduced in PI. 14, figs. 7 and 2. This is a pig-
ment color caused by minute and highly refractive orange or yellow pigment
granules which crowd the ectoderm cells over the regions of the gastro-

vascular system. A study of sections shows that these same granules occur

92 THE MEDUSAE.

in the ectoderm in other regions as well; but it is only over the stomach
and canals that the ectoderm layer is thick enough for them to produce
a visible color. I have been unable to find any pigment granules in the
endoderm.

Pegantha smaragdina, like Cunina proboscidea, as already stated, exhibits
an alternation of generations of medusae, our smaller specimen showing
an almost complete series of stages in the development of the secondary
generation. These will be described in detail in the ensuing pages. For
the sake of completing the systematic description of the species I must, even
at the cost of repetition, insert here an account of its most advanced stage.
The oldest medusae of this secondary generation were ready for independent
existence, and were taken in the same haul with their parent-host. They
measure about 3 mm. in diameter and are very flat. An aboral view of one
is shown in Pl. 26, fig. 5. Their most important structural feature is that
they lack canal system and otoporpae. There are from ten to twelve ten-
tacles and from one to three otocysts per marginal lappet. The lappets are
short and broad, the incisions between them hardly marked. The stomach
is a simple circular sac. <A section of the oral gastric wall (Pl. 24, fig. 7)
shows that it already consists of many layers of densely crowded ectoderm
cells, —a fact which suggests an early formation of sexual products, such as
takes place in the corresponding generation of Cunina proboscidea, as described
by both Metschnikoff (’86*) and Stchelkanowzew (: 06). Apparently the sex
cells are developed generally over the stomach surface —a fact which, taken
together with the absence of gastric pockets, canals, and otoporpae, would
throw the specimens into the genus Solmaris, were their parentage not
known. :

The only described species of Pegantha at all approaching P. smaragdina
in either size or number of tentacles is P, magnifica Haeckel, which is 50 mm.
in diameter, with thirty tentacles; but the two species are so sharply sepa-
rated by form, shape of the marginal lappets, conformation of the gonads,
and number of otocysts (Haeckel, ’79, p. 333, records 900-1000 of these
organs for P. magnifica) that there can be no question that they are distinct. It
is perhaps possible that P. smaragdina may be identical with the specimen de-
scribed by Brandt (38, p. 364, taf. 7) from Mertens’s figures as Polyzxenia
flavibraclua; bat since his figures show neither canals, stomach, gonads, nor
sense organs, it is absolutely impossible to tell definitely even the family

to which this form belongs.

PEGANTHA SMARAGDINA. 93

DEVELOPMENT OF THE PARASITIC GENERATION OF PEGANTHA SMARAGDINA.
Plates 22-26.

Up to the present time the only accounts of the development of a sec-
ondary, parasitic generation of medusae within the parent which have
appeared are those by Metschnikoff (’86*) and Stchelkanowzew (:06) for
Cunina proboscidea Metsch., and these two, though agreeing as to the main
features, differ from each other in many details. An important difference
between Cunina and Pegantha is the region in which development takes
place; for in the former, according to both authors above cited, it is re-
stricted to the mesogloea and endoderm of the subumbrella in the region of
the gastric pockets and peronial canals, while in Pegantha I have found
it only in the gelatinous substance of the exumbrella, in the region of, and
close to the margin of the gastric cavity. It occurs only in the smaller of
our two specimens ; 7. e. the one in which no gonads are to be seen.

Although I have not been able to trace the earliest stages, or to find any-
thing suggesting fertilization, there is no reason to doubt that the develop-
ment is that of a fertilized ovum, as Stchelkanowzew (: 06) has shown to be
the case in Cunina proboscidea; for although no discrete gonads are present in
the specimen, yet it is possible that the ova in this species as well as in C.
proboscidea develop, not in localized masses, but irregularly over the oral
surface of the gastric wall, where their small size and resemblance to ordi-
nary ectoderm cells would render them difficult to recognize. Amoeboid cells
such as Metschnikoff describes are very common in various regions of the
jelly of the present species, and I can strongly support the accuracy of his
observations that they divide by mitosis (PI. 22, fig. 8), and may unite in
pairs (Pl. 22 figs. 70, 11). I have found no evidence, however, that such pairs are
the two resultants of the previous division of a single parent cell, or that the
union is anything more than an accidental one. Stchelkanowzew has sug-
gested (:06, p. 459) that these amoeboid cells (which he did not observe)
are in reality the spermatozoa. The facts that they differ enormously
in size (cf. Pl. 22, fig. 1 with figs. 2-4), and especially that they show mitotic
division, suggest that this explanation is not correct.

The earliest stage undoubtedly belonging to the developmental series is
represented in Pl. 22, fig. 72. It contains two nuclei, and study of several
specimens has shown beyond question that it consists of two cells, one en-

closing the other. The inner cell, the future larva, is spherical, its nucleus

94 THE MEDUSAE.

large, its cytoplasm dense and homogeneous. The outer cell, which, follow-
ing Metschnikoff, we may call the nurse-cell, and which appears to have
only a nutritive function, has vacuolated cytoplasm. The boundaries of the
two cells are easily distinguished, the sharpness of limitation in the figures
being no exaggeration of that in the specimens. The inner cell divides by
mitosis (Pl. 22, fig. 18); two and four-cell stages were frequently observed
(Pl. 22, fig. 74; Pl. 23, figs. 7, 2); and through successive divisions a typical
morula is formed (PI. 23, figs. 5-7). The cleavage closely resembles the pro-
cess as described by Metschnikoff, except that he found no stages in mitosis.
Division of the cells is complete, and the boundaries of the blastomeres dis-
tinct and easily seen. Stchelkanowzew describes the cleavage of Cunina as
superficial, the nuclei alone dividing, and thus forming a syneytium ; but his
ficures suggest that his material was not very satisfactory, so that in view of
the close correspondence of the present material with Metschnikoff’s account,
I am inclined to believe that cleavage is normally total. During all these
stages the nurse-cell persists, and in all favorable examples its cytoplasmic
body can easily be distinguished by its vacuolated nature and clearly visible
outline from the cells of the larva which it encloses. The nucleus of the
nurse-cell grows until its diameter is two or three times that of the nuclei
of the morula, and becomes flattened until it forms a sort of cap to the
latter (PI. 23, figs. 6, 7). It may remain single, or may divide directly
once or twice, and there is some evidence that one or more of the nuclei
resulting from such division may degenerate. This history of the nurse-cell
agrees closely with Metschnikoff’s account. Stchelkanowzew, however, could
find no such structure in the early stages, while in the morula stage he
observed two nurse-cells (: 06, taf. 30, figs. 32, 33, 35, n, n’), which he be-
lieves are modified ectoderm cells of the larva, situated at the two poles of
the latter. According to his view, the cells which Metschnikoff described as
nurse-cells in early cleavage stages are nothing more than blastomeres.
I feel certain that, Metschnikoff’s interpretation is the correct one, at least for
the present species, since the history of the nuclei as well as the structure
of the cytoplasm clearly distinguishes nurse-cell from blastomere; while
the preparations are so clear as to leave no doubt that the former encloses
the latter.

The embryo up to now lies within the jelly, close to the endoderm layer.
Later stages, however, are to be seen only in the gastric cavity, or in the
peripheral canals. The nurse-cell is apparently destroyed during the passage

PEGANTHA SMARAGDINA. 95

of the larva through the endoderm; at least it is absent in larvae which
have penetrated into the gastric cavity.

The endoderm originates, as both Stchelkanowzew and Metschnikoff agree,
by secondary delamination, there being no trace of any invagination. Even
in such an early stage as that represented in Pl. 23, fig. 7, the four or five
central cells are already sharply defined from the surrounding layer, and as
development progresses the distinction is made more and more evident both
by the differentiation of the endoderm cells, and by the development of a gelat-
inous layer between the two germ layers. The process in all respects agrees
with the descriptions of Metschnikoff, the resemblance between his figures
and corresponding stages in Pegantha being very striking.

Later development. — After entering the gastric cavity of the parent, the
larva grows rapidly in size and becomes spindle shaped. The ectoderm cells
multiply proportionately with the growth; but the endoderm cells multiply
very slowly, but increase in bulk (Pl. 23, figs. 7-17), and gradually assume a
chordate outline until they resemble the cells of the endodermic core of an
adult tentacle. Indeed larvae at this stage very much resemble small
detached tentacles. The earliest stage in which I have found a gastric
cavity is represented in Pl. 24, fig. 2. I have been unable to find stages
in the formation of the cavity. At a slightly more advanced stage the
mouth, already foreshadowed by the thinness of the wall in PI. 24, fig. 2, breaks
through. At about this same time the development of the primary tentacle
commences. Apparently the main portion of the larva goes to form the
tentacle, as is the case with the two primary tentacles in Solmundella
(Metschnikoff, ’86*). A second tentacle is developed opposite the first ;
other tentacles then appear irregularly, specimens having been observed
with three, four, and five.

Budding. — Larvae with four or more tentacles often show stages in bud-
ding very similar to those described in detail by Metschnikoff (74) for
Cunina prolifera. He likewise seems to have observed one or two instances
of this mode of multiplication in Cunina proboscidea (86°, taf. 12, figs. 4, 13),
although Stchelkanowzew, not having found any himself, doubts their occur-
rence. In Pegantha smaragdina budding larvae are very numerous in the pero-
nial and ring canals of the parent-host (PI. 19, fig. 5). Budding takes place
at the aboral pole, and comprises both germ layers, as well as a portion of
the gastric cavity (PI. 24, figs. 3, 5). Surface views of a number of stages

are represented on Pl. 25. The bud may become constricted and separate

96 THE MEDUSAE.

from the parent larva while still a mere sac (PI. 25, fig. 6), or it may remain
attached and develop tentacles and a mouth which breaks through at the

pole opposite that of attachment (PI. 24, fig. 6); the tentacles are developed |

in the sequence already described. A second bud may be formed from the
aboral plate of the parent while the first is still attached (Pl. 24, fig. 6; Pl.
25, figs. 7-9), but I have never seen more than two; nor have I seen any
trace of the development of tentacles in the second while the first was still
attached to it. Bud larvae being indistinguishable after detachment from
larvae developed directly from the egg, it is impossible to tell how many
generations of polyps may be formed by budding, or whether all develop into
medusae.

The metamorphosis of the polyp larvae into medusae consists chiefly of a
flattening caused by disproportionate growth on the part of the aboral disc
between the bases of the tentacles. Successive stages in this process, which
has been described by Metschnikoff (’86*), are shown in PI. 26, figs. 1 to 5.
As noted by that author, the collar region first appears as a ridge sur-
rounding the larva just oral to the tentacles. The collar, then, does not
pass through a lobed stage, but is continuous from the beginning. We
must, however, regard the peroniae as representing obliterated incisions
between ancestral lobes. Thus it appears that, although morphologically the
tentacles may be regarded as standing on the bell margin, in this species
they never do so in actual development, since they are already some distance
within the margin when the latter is first distinguishable as such. In this
respect P. smaragdina differs from Cunoctantha octonaria, in which, according
to both Brooks (’86) and H. V. Wilson (’87), the marginal lappets result from
an outgrowth of the aboral surface beéween the tentacles, phylogenetically a
more primitive condition.

The flattening continues with growth until the largest specimens, 12 mm.
in diameter, are disc-like (Pl. 26, fig. 5), and at the same time the number of
tentacles increases, the greatest number observed being thirteen. Octocysts
are first distinguishable in the stage represented in Pl. 26, fig. 4, where
they are merely papilliform processes of the margin, comprising both germ
layers exactly like rudimentary tentacles (PI. 26, fig. 6). Soon from one
to five otoliths are formed, appearing first at the distal end (PI. 24, fig. 8),
and as the sense organ attains its mature form the connection of its endo-
dermic core with the vascular endodermic layer is lost (Pl. 24, fig. 7). There

are no otoporpae.

PEGANTHA LAEVIS. 97

The gelatinous substance of the disc, always thin, first appears at about
the stage represented in Pl. 26, fig. 4. As already noted (p. 92), no canal
system is developed. The velum first appears as a ridge-like ectodermic
thickening just oral to the nerve ring (PI. 24, fig. 8). With further develop-
ment it increases in breadth until it attains the practically adult condition
represented in cross section (Pl. 24, fig. 7).

The medusa is now ready for independent existence, and swims vigorously,
as I observed in living specimens. Metschnikoff (’86*) has found a similar
active condition in Cunina proboscidea. But Stchelkanowzew, writing of the
same species, declares (: 06, p. 478) that the young are mere sacs full of gen-
ital products, never fitted for independent existence. Both these authors
agree that in Cunina the parasitic generation becomes sexually mature at
a stage no more advanced than that above described (Pl. 26, fig. 5).
This is not the case in Pegantha, although the fact that at this stage the
ectoderm of the oral gastric wall is already many cells deep (PI. 24, fig. 7)
very strongly suggests that the medusae are nearly mature and that the
sexual products would soon be developed. The important systematic feat-
ure of the oldest medusae, 7. e. lack of canals and of otoporpae, has
already been noted (p. 92) in the systematic account of this species,

Pegantha laevis, sp. nov.

Plate 16, Fig. 7; Plate 20, Figs. 4-6 ; Plate 27, Figs. 1-7.

Station. Depth. Diameter. Rp orl Gonads.

mm
AGpOmelsourtace . . . . - 41 22 Large g | 1 fair specimen. Type.
4650 | 300 fathoms to surface 34 19 Large 2 | 1 fragmentary specimen.
4650 | 300 fathoms to surface 30 16 None 1 fair specimen.
SCOMSUTTACe: « «+ + « 28 18 None 1 fair specimen.

I likewise found an example of this species in the collection made by
the “ Albatross” in the Hawaiian Islands.

The bell is very flat for this genus, being only about one fourth as high
as broad ; the dise lenticular; the exumbrellar surface of the dise smooth,
without any trace of sculpture (PI. 16, fig. 7); but, as in all other members
of the genus, there are slight ridges on the marginal lappets along the lines
of the otoporpae. There is also a slight coronal furrow, separating the

central disc from the marginal zone. The gelatinuous substance is softer

98 THE MEDUSAE.

than in other species of Pegantha which I have examined. It is possible,
however, that this feature may be due to the rather unsatisfactory condition
of the specimens. The marginal lappets are about as broad as long, and
somewhat pentagonal in outline (PI. 20, fig. 5), though less so than Maas
has figured them for P. dactyletra (93, taf. 5, figs. 1, 2). The incisions
between the lappets are shallow and the peroniae correspondingly long.

Tentacles. — The greatest number of tentacles and lappets 1s twenty-two,
in the largest specimen, while the only other individual with gonads has
nineteen. The number, though variable, is thus considerably larger than
in either P. martagon or P. triloba. A specimen 30 mm. in diameter, which
as yet shows no trace of gonads, has only sixteen tentacles, one of them
evidently of much more recent formation than the others (PI. 20, fig. 4);
but since no trace of the sexual organs is yet visible in this specimen, it is
by no means certain that sixteen would have been the final number. The
tentacles are of the usual type; about two thirds as long as the diameter
of the bell, and in life carried projecting stiffly (Pl. 16, fig. 7).

Otocysts. —There are usually seven otocysts per lappet in the larger speci-
mens; but unfortunately the margins of both adult individuals were so
battered that I could count them in only a few lappets. The sense organs
themselves (Pl. 20, fig. 6) are oval in outline, contain two or three otoliths,
and are situated on small ectodermic pads. The otoporpae are much shorter
than in other members of the genus which I have examined, extending hardly
across the ring canal (Pl. 20, fig. 4; Pl. 27, fig. 2).

Gastro-vascular system.— The stomach is flat. In young specimens, in
which its form is not obscured by the gonads, it is circular (Pl. 20, fig. 4).
The mouth is surrounded by a simple circular lip, in all the present speci-
mens widely opened. The canal system is well developed, both peronial and
ring canals being very broad.

Gonads. — The gonads are not definitely subdivided, but, asin P. martagon,
each consists of a single main swelling, which, in the present species, bears
a variable number of oval or papilliform processes (Pl. 20, fig. 5). On com-
parison with Maas’s figure (’93, taf. 5, fig. 2) it will be seen that this type of
gonad very closely resembles that of P. ductyletra, differing only in that the
finger-like processes in P. /aevis are smaller,—a difference of doubtful impor-
tance, since it is by no means certain that the gonads of any of the present
specimens have reached their maximum development. As in the three other
species of Pegantha described in this paper, each gonad is supported by a

rounded prominence of the gelatinous disc.

PEGANTHA LAEVIS. 99

P. laevis is entirely colorless; the disc hyaline, the endodermic system
nearly opaque.

This species differs from all of the forms described by Haeckel (’79)
in form of gonads, number of otocysts, number of tentacles, and lack of
exumbrellar sculpture. It is, on the other hand, very closely related to the
P. daetyletra described by Maas (93, p. 47) from the Tropical Atlantic. As
already pointed out, the gonads of the two forms are very similar, the slight
differences between his account and the present specimens being easily
explicable as the result of different stages in growth. The number of oto-
cysts (five to seven per lappet) and the pentagonal form of the marginal
lappets likewise agree in the two species. There is an apparent difference in
the number of tentacles, Maas recording only sixteen for P. dactyletra; but I
doubt whether this indicates anything more than individual variation, since
one of the two adult specimens in the present collection has only eighteen,
and since Maas had only a single specimen of P. dactyletra. Of no more impor-
tance is the apparent difference in size, for the “ Plankton” specimen was
described by Maas after preservation (with osmic acid), and therefore the
diameter which he gives, 30 mm., is no doubt smaller than the Medusa
actually was in life. The only important distinction seems to be the pres-
ence of a well-marked exumbrellar sculpture in P. dactyletra, and its entire
absence in P. laevis. It is, of course, impossible to state whether this feature
is constant until more specimens, particularly of P. dactyletra, are examined ;
but since sculpture is an important character in other members of the genus,
it seems best to recognize the present form as a distinct species, at least for
the present.

The capture of a specimen of this species by the “ Albatross ” among the
Hawaiian Islands shows that it, like P. ¢ridoba, is of very general distribu-
tion throughout the Eastern Pacific.

Pegantha laevis, as already noted (p. 9), shows the early stages in a type
of internal budding very similar to that which I have described (p. 62) for
Cunina peregrina, In the present species, however, the process takes place,
not in the gastric cavity proper, as in Cunina, but in the peripheral canals
(ring canal alone?). In a budding individual the oral wall of the ring canal
bears irregular ridges and swellings (PI. 27, fig. 1), which vary in form. On
sections it is seen that these ridges are purely endodermie structures, the
ectoderm taking no part in their formation; but here, as in Cunina, I must

acknowledge the possibility of a migration into the budding region of amoe-

100 THE MEDUSAE.

boid ectoderm-cells, although I have seen no indication of the occurrence of
such a process. The ridges, as in Cunina, are proliferating regions, from
which the true buds or planulae are given off, but, in Pegantha, budding
instead of being restricted to them, may take place from the undifferentiated
endoderm in other regions of the canal (Pl. 27, fig. 5). The buds are solid,
ciliated, morula-like structures, in which the cell boundaries are easily dis-
tinguishable (PI. 27, figs. 6, 7). A considerable number were found lying free
in the gastric cavity, but since no further advanced stages were observed, it
is probable that they now pass out through the mouth of the parent, to con-
tinue their development either independently or in some other host.

TRACHOMEDUSAE.

Most authors now recognize in this order six families:—Petasidae, Pectyl-
lidae, Geryonidae, Halicreasidae, Aglauridae, and Trachynemidae. Of these
the first four are well marked, and probably represent natural phylogenetic
groupings, but the separation between the last two seems to be based on
unsatisfactory grounds. Thus, as Maas (: 06%, p. 494) has already pointed
out, the presence or absence of a gelatinous peduncle, considered by Haeckel
(79) the most important character separating Aglauridae from Trachyne-
midae is of much less taxonomic importance than has usually been sup-
a conclusion strongly supported by the fact that the new genus
Tetrorchis in the present collection, very closely related to Aglaura in so far
as the structure of the gonads is concerned, lacks a peduncle.

The conformation of the gonads, whether extending along the radial
canals or hanging free in the bell cavity, seems to me of but little more
systematic significance, since this criterion, if rigidly applied, must lead to

posed,

the removal of Agliscera from the Aglauridae, although its closest natural
allies are undoubtedly the genera Aglaura and Aglantha. The form of the
bell is certainly not a family characteristic, for either a high or a low bell may
be associated with a peduncle, or with either linear or pendent gonads ; nor
can we use the otocysts, whether free or enclosed, as a family character, as
srowne (: 04) has done, without confusing other structural characters which
apparently are fully as important. There is one character which seems
to me to be more significant than has usually been supposed ; that is, whether
the tentacles are of one or of two kinds, but even this can hardly be made
the basis of family distinction, since to do so would result in separating Rho-

palonema from genera to which it is universally believed to be closely related.

PETASIDAE. 101

On the whole, it is best to discard the separation between Trachynemidae
and Aglauridae, and to unite the component genera of the two
into one family, for which the older name Trachynemidae may be retained.
This family will then be characterized as: — Trachomedusae with eight radial
canals; without blind centripetal canals ; with well-developed manubrium ;
with numerous tentacles arranged in a single series, but of either one or two
kinds; gonads either pendent or linear.

The collection contains fifteen genera and eighteen species of Trachome-
dusae, of which two genera, three speciesand one variety are believed to benew.

Petasidae Haeckel, 1879.
sens. em. Browne (: 04).

Trachomedusae with four or six radial canals on which the gonads are
borne; with either enclosed sense capsules or free sensory clubs.

We may well follow Browne in separating the Petasidae into two sub-
families, Petachninae and Olindiinae, according as the otocysts are free
clubs or enclosed capsules. The present collection contains members of the
Olindiinae only. Indeed, so far as I can learn, no one since Haeckel has
observed any members of the Petachninae. ‘

Although Goto (:03) believes, from his studies on the development of
Olindioides, that the sense organs of Olindioides are ectodermic, and that
the Olindiinae therefore belong to the Leptomedusae, recent students
(Browne, : 04, Mayer, : 04, Maas, :05) agree in classing them among the
Trachomedusae. Certainly in all respects, except possibly the origin of the
otocysts, they are typical of this order; and very recently doubt has been
thrown on Goto’s conclusion, that the sense organs are ectodermic, by
Murbach, who makes the positive statement (: 07, p. 2, footnote) that in
Gonionemus murbachii, at least, they are of endodermic tissue. I therefore
retain the Olindiinae among the Trachomedusae, where I believe they un-
doubtedly belong.

Mayer (: 04) makes the presence of sucking dises one of the distinguishing
features of this family, thus excluding Gossea and Aglauropsis. Both of
these genera, however, are in other respects closely allied to Gonionemus ;
Aglauropsis even being believed by Maas (:05) to be a synonym of the
latter, so that it is better to consider this character, with Browne (: 04), as
of generic value only. I regret that my account of rudimentary sucking
discs in Gonionemus pelagicus should have led Maas (: 05) to believe that

102 THE MEDUSAE.

=

these structures may be variable in any genus, for a renewed examination
of the original specimens has shown that my description was erroneous in
this respect. Maas, arguing from this conclusion, believes that the status
of Aglauropsis and of Vallentinia is doubtful; the former he is inclined
to unite with Gonionemus, the latter with Cubaia. I see no reason
to doubt the diagnoses of these two genera, given from new material, by
such a careful student as Browne, and therefore retain them. The char-
acters of greatest taxonomic value within the family are, as all recent
students agree, the presence or absence of centripetal canals; the presence
of one or of two distinct series of tentacles; the arrangement of tentacles,
whether uniform or in groups; and (although Maas dissents from this) the
presence or absence of sucking discs on certain of tlie tentacles. As to
which of these are of greater, which of less value, it is difficult to determine.
It seems to me that considerable weight is to be Jaid on whether the ten-
tacles are in a single series or in two series; this character being, as we know
from the studies of Mayer (: 04), one intimately connected with ontogeny. The
same is likewise true, though in less degree, of the presence or absence of
centripetal canals. Mayer has given taxonomic weight to the conformation
of the gonads, whethef papilliform or sac-like; but this is a character
which changes much with growth, and one which I believe to be of minor
importance.
The genera may be tabulated in the following artificial key : —
A. With one kind of tentacles.
1. Tentacles without suckers ; no centripetal canals.
Tentacles not in groups. Aglauropsis (? Maeotias, Ostroumoff).
Tentacles in groups. Gossea.
2. Tentacles with suckers. Gonionemus.
B. With two kinds of tentacles.
1. Without centripetal canals.
Four perradial tentacles alone with sucking discs. Vallentinia.
Two series of tentacles ; the numerous primary tentacles all
with sucking dises. Cubaia.
2. With centripetal canals. Primary tentacles with sucking dises.
Four radial canals. Olindias.
Six radial canals. Olindioides.
We must bear in mind that the tentacles of group A correspond (as Mayer
: 04 has shown) to the primary tentacles of group B.

GOSSEA BRACHYMERA. 105

The present collection contains specimens of three of these genera, Gossea,
Gonionemus, and Olindias.

Gossea L. Agassiz, 1862.

sens. em. Browne (: 04).

Olindiinae with tentacles of one kind only, arranged in eight groups, and
with other single tentacles or cirri; without sucking pads on any of the
tentacles; without centripetal canals.

Gosse (’53, p. 407, pl. 21) has given us an excellent description and
unusually beautiful figures of his Thawmantias corynetes, for which L. Agassiz
later founded the genus Gossea; and a second species has been described by
Haeckel (’79) under the name G. circinata, from the coast of France, but
the latter is almost certainly nothing more than an older stage of
G. corynetes. The only important differences between the two are the pres-
ence of three members in each tentacle group in G. circinata instead of two
and a small spur, as in G. corynetes; and the presence in the former of adradial
cirri, which are lacking in the latter; but these differences are merely
developmental characters, since Gosse (’53) has himself mentioned the dis-
covery of a few specimens of G. corynetes in which the third tentacle in
each group was considerably larger than it appears in his figures.

Gossea brachymera, sp. nov.
Plate 50, Figs. 1-10.

Acapulco Harbor ; surface; 1 specimen, 5 mm. in diameter, 4 mm. high.

Fortunately the single specimen was in such excellent condition as to enable
me to study and illustrate it in detail.

The bell is high, dome-shaped (PI. 30, fig. 7) ; the gelatinous substance stiff
and so thick that the umbrellar cavity is very shallow. The manubrium,
supported on a short, broad peduncle, is very short. In G. corynetes there is
no peduncle. There are four triangular, slightly fimbriated lips.

Bell margin. — The arrangement of the tentacles is of course the most char-
acteristic feature of Gossea, and in this respect the present specimen shows a
condition either less advanced (if it prove to be merely an early stage of devel-
opment) or more primitive (if it be the final condition) than does @. corynetes.

There are eight groups of tentacles, four perradial and four interradial, and

104 THE MEDUSAE.

in addition eight adradial tentacles which are single. Each tentacle group
consists of two members, rising side by side from a single bulb (Pl. 30,
figs. 7-9); one about as long as the bell diameter, ringed with nettle cells,
solid, arising from the surface of the exumbrella some distance above the
actual margin, and connected with the ring canal by an endodermic root
just as are the exumbral tentacles of Olindias, with a nettle cluster at. the
tip, but no sucking disc (Pl. 30, fig. 6); the other is so short as to be hardly
more than a spur, and arises directly from the nematocyst pad. It shows,
however, the earliest stages in the development of nettle rings, and bears
at its tip a nettle pad, clearly visible in the photographs. Alternating with
these eight groups are eight simple tentacles, resembling in structure the
large members of the tentacle groups, though smaller than the latter.
Finally, alternating with these sixteen tentacles and groups are sixteen
swellings or papillae clearly seen in the photograph (Pl. 30, fig. 2). In
G. corynetes, according to Haeckel (’79), there are the same number of
groups of tentacles, 7.e. eight; but each contains three nearly equal
members, while Gosse’s figures of younger specimens show three, two large
and one very small. It is evident, then, that the full number is not attained
until an advanced stage in development is reached. The single adradial
tentacles evidently correspond to the adradial cirri of G. corynetes, but are
much larger. The latter species appears to lack the rudimentary bulbs or
papillae seen in the present specimen. If Haeckel’s (’79) account be
correct, another important difference between the two species is in the
structure of the tentacles, for while he describes them as hollow in
G. corynetes, in the present species they are solid, with a core of chordate
endoderm cells (Pl. 30, fig. 10).

Olocysts. —In spite of the good condition of the specimen I am unable to
give any account of the otocysts. Most careful search with the microscope
failed to reveal any on the bell margin, although both Gosse (’53) and
Haeckel (79) agree that in G. corynetes two or three otocysts occur on the mar-
gin between every two groups of tentacles. In the present species, however,
they appear to be replaced by the rudimentary tentacular papillae, which are
solid and bear no resemblance to sense organs. In one case I distinguished
near the base of one of the primary members of a tentacle group what ap-
pears to be an otocyst (Pl. 30, fig. 5), so that, although I was unable to find
any in connection with other tentacles, it is not unlikely that the otocysts in
this species occupy the same position that they do in Olindias.

GONIONEMUS. 105

Gonads. — These, as in G'. corynetes, are simple folds extending along the
oral surfaces of the radial canals, without papillae or secondary plications.
They occupy about the central third of the canals. In the single specimen
they are full of moderate-sized ova.

Color.— The specimen was not examined until after preservation.
Gonads, tentacles, and manubrium are pale yellowish brown, and the bell
hyaline. In G. corynetes there are one or two red or brown spots at the base of
each tentacle group, but these are lacking in G. brachymera.

The presence of a well-marked peduncle serves to separate this species
from G. corynetes, and may be considered its most important specific character.
The condition of the tentacles is also of taxonomic value, the large size of
the single perradial tentacles, and the presence of rudimentary papillae on
the bell margin sharply distinguishing it from the North Atlantic species. If,
as seems probable from the advanced state of the sexual organs, the number
(two) of members in each tentacle group is the final one, this forms another

important difference between the two species.

Gonionemus A. Agassiz, 1862.

Olindiinae with four radial canals; without centripetal canals; with a
single series of tentacles not in groups; each tentacle with a sucking disc.

Since the description of the original species of this genus, Gonionemus
vertens, by A. Agassiz (’65), six additional species have been described : —G.
murbachii Mayer (: 04), G. suvaensis Agassiz and Mayer (’99), G. depressum Goto
(: 03), G. agassizii Murbach and Shearer (: 03), G. pelagicus Bigelow (: 04), and
G. hornelli Browne (: 05”). Fortunately, all these have been well described and
figured. I have been able to examine specimens of G. vertens (type), G.
suvaensis (type), G. pelagicus (type), and a very considerable series of @,
murbachii, in addition to the specimens in the present collection.

The species fall into two well-marked groups : —

A. With sixteen otocysts; with the gonads distal, occupying from one
fourth to one third of the radial canals. This includes G. swvaensis,
G. hornelli, G. pelagicus.

B. With at least as many otocysts as tentacles; number of otocysts
variable ; gonads occupying nearly the entire length of the radial
canals; G. vertens, G. agassiait, G'. depressum, G. murbachit.

I have not been able to find good distinctions between the three “ spe-
cies” of group A. All have about the same number of tentacles (seventy to

106 THE MEDUSAE.

eighty), about the same bell outline and conformation of gonads, and essen-
tially similar coloration. Browne states that in G. hornelli the tentacles are
arranged in sixteen groups; but from an examination of his figure (: 05",
pl. 1, fig. 6) it appears that this grouping indicates the location of the
sixteen otocysts, and is in no way comparable to such a grouping of tenta-
cles as is seen in Gossea (p. 103). In my description of G. pelagicus (: 04,
p. 256) I considered the small size of the sucking discs of this species suffi-
cient to separate it specifically from @. swvaensis ; but a second examination of
the specimen has shown that this supposed character is variable in different
tentacles, and perhaps due largely to preservation, so that I was not justified
in making a new species for this form, which is really G. swvaensis.

In the second group, characterized by the form of the gonads and by
having a large and variable number of otocysts, it appears that several good
species can be distinguished. The number of ctocysts, even though variable,
is apparently of specific significance, for while G. vertens and G. murbachii have
about as many otocysts as tentacles or slightly fewer, G. depressum and the
specimens described by Kirkpatrick (: 03) under the name G. agassizw have
nearly or quite twice as many, and this difference is apparently constant, for
very considerable series of G vertens and G'. murbachii have now been examined by
various observers; the latter, owing to its common use as laboratory material
and as subject forexperiment, being very well known indeed. The differences
between G. vertens and G. murbachii are slight, consisting of a slightly higher
bell in the former and stouter tentacles in the latter; but they appear to be
constant, and must therefore be recognized in the nomenclature of the genus.

Gonionemus depressum Goto, and the specimens described by Kirkpatrick
(:03) as G. agassizii Murbach and Shearer, both from Japan, are undoubtedly
identical, agreeing as they do in the form of the gonads, number and form of the
tentacles, and number of otocysts; but it is doubtful whether Kirkpatrick’s
identification of his specimens with Murbach and Shearer’s (: 03) species is
correct ; for, while the latter authors state that G. agassizii has rather fewer
otocysts than tentacles (though without giving actual figures), Kirkpatrick
(: 03) finds the otocysts almost twice as numerous as the tentacles. For
this reason I prefer, at least for the present, to retain both G. depressum and
G. agassizii as distinct species, classing Kirkpatrick’s specimens as G. depressum.
The distinction between G. agassizii aud G. vertens, the greater number of ten-
tacles of the former, must be tested in a larger series before a final decision

can be reached.

GONIONEMUS SUVAENSIS. 107

Gonionemus suvaensis Agassiz and Mayer.

Gonionemus suvaensis Agassiz and Mayer, ’99, p. 164, pl. 5, figs. 14-16.
Gonionemus pelagicus Bigelow, : 04, p. 256, pl. 4, figs. 12-14.
Gonionemus hornelli Browne, : 05°, p. 149, pl. 1, fig. 6, pl. 2, fig. 4.

Plate 3, Figs. 4,5; Plate 32, Figs. 1-7.

Mangareva Harbor; surface; 12 specimens, ranging in diameter from
4mm. to 10.56 mm.

The high arched bell and the considerable length of the manubrium are
shown in the photograph Pl. 3, fig. 5. As in Browne’s specimens, the
manubrium is situated on a very low peduncle, which is just visible in the
side view in Pl. 3, fig. 5.

In the smallest specimen there are fifty-two, in the largest about eighty
tentacles ; all have sixteen otocysts, four per quadrant (PI. 32, fig. 1). Each
otocyst contains a single spherical otolith (Pl. 32, fig. 6). The tentacles are
of different sizes, the longest about one third as long as the bell diameter,
and stout; their sucking discs, very prominent (PI. 32, fig. 3), at about mid-
way of their length; but the exact position of these organs depends somewhat
on the state of contraction of the tentacles. Even in the small specimens
gonads are present, while in the larger ones they are well developed and ap-
proaching sexual maturity. Their characteristic location, restricted to the
distal fourth or third of the radial canals, is well shown in the photographs
of side and oral views (PI. 3, figs. 4 and 5). In small specimens the sexual
organs consist-of a more or less wavy fold on the oral surfaces of the radial
canals, but with advancing development the plications of the fold increase,
until finally they become very complex (PI. 32, fig. 5). The essentially
ribbon-like structure is always retained, there being no papilliform processes,
such as are formed in the closely allied genus Olindias. My figure of the
gonad of the Maldive specimen (:04, pl. 4, fig. 13) was incorrect in this
respect. An interesting abnormality was exhibited by one specimen which
had only a single radial canal, with one very large gonad (Pl. 32, fig. 7).

Color. — The gonads are brownish red; tentacles and tentacular bulbs pale
yellowish. The Fiji specimens figured by Agassiz and Mayer (’99) had green
pigment spots at the bases of the tentacles, while in the Maldive specimen
(Bigelow, :04) these pigment spots were brown. There is thus consider-
able local variation in the pigmentation of this species.

Gonionemus suvaensis differs from the G. vertens group not only structurally

108 THE MEDUSAE.

but in its habits. While the latter have usually been recorded from land-
locked ponds or harbors, where they often cling to Algae, G. suvaensis is
more truly pelagic, occurring in open sounds and lagoons, or on the surface
of the open sea (Bigelow, :04). Although it has been observed in life at
Mangareva, among the Maldive Islands (Bigelow, :04), and among the
Fiji Islands (Agassiz and Mayer, 799), it has never been seen to exhibit
the peculiar “turning” habit of swimming so characteristic of G. vertens,
G. murbachi, and G. depressum (Goto, : 03).

This species is widely distributed over the Tropical Pacific and Indian
Oceans, but appears to be restricted to shoal-water regions in the close
neighborhood of land.

Olindias F. Miiller, 1861.
Halicalyx Fewkes, 782°.
Halicalyx Mayer, : 00°.

Olindiinae with four radial canals, with two kinds of tentacles, the pri-
mary tentacles bearing sucking dises; with blind centripetal canals.

Maas (: 05) has pointed out that the Atlantic forms of this genus, 0. phos-
phorica Della Chiaje (miillert Haeckel), O. sambaquensis F. Miiller, and O. tenws
Mayer (Fewkes?), can hardly be distinguished, since the various characters
which have been supposed to separate them, ¢. e. conformation and lobing of
the gonads, and number of marginal organs, not only change with advanc-
ing development, but are subject to great individual variation (see Table,
p- 109). Asa variety of this one Atlantic species, he identifies specimens in
the “Siboga” collection, from the Malay Archipelago, under the name O.
phosphorica, var. malayensis.

Browne (: 04) has recently described under the name O. singularis another
species distinguishable from O. miiller? and its varieties by the presence of
distinct bulbs at the bases of the secondary (velar) tentacles, and of only one
otocyst, instead of a pair, at the base of each primary tentacle. The present
specimens, as well as an excellently preserved specimen from Dutch Papua,
appear to belong to O. singularis Browne, although this large series shows
that Browne’s original description, taken from but a single specimen, must
be somewhat modified.

Maas (:05, p. 48) has compiled a table of the numerical condition of
canals and tentacular structures; but since his figures, though illustrating

very well their variability, do not altogether agree with my observations

OLINDIAS SINGULARIS. 109

on a considerable series from different localities, the following table is
appended. ‘The chief difference is that I have found a proportionately
greater number of primary (exumbral) tentacles than either Haeckel (’79),
Maas (: 05), or Mayer (: 00", : 04) have recorded, and proportionately fewer

secondary tentacles and tentacular bulbs.

Species, Locality, Authority. ey | Secondary Bulbs. per primary ieee Uf at
en e. - ;

miilleri. Mediterranean, Haeckel) 50-60 | 100-120) 100-120 2 11-19 40-60
miilleri. Mediterranean, mihi 109 84 145 2 12,14,16,11| 61
milleri. Mediterranean, Goto S06 35 =|140-170 2 auane 50

milleri. var. malayensis, Maas | 20-30 | 30-40 | 120 2 7-9 25-35

sambaquensis. Brazil, Miller | 80-100} 200-300) 100-120 2 21-27 70-100
tenuis. Tortugas, Mayer 32 60 64 2 7 35
tenuis. Key West, mihi 51 38 64. 2 10, 6, 10,8 27
tenuis. Bermuda, mihi 54 56 69 2 SG Lees 23
singularis. Maldives, Browne | 30-40 | 16-20 | 30-40 1 4-5 13
singularis. Maldives, mihi ab’t 45 | ab’t 30 | ab’t 50 |1 at most 6-7 20
singularis. Mangareva, mihi | 86 50 104 | ee 1944.19.11) 36
singularis. Mangareva, mihi | 69 48 98 | pet ee lis) 88,9 | 25
singularis. Mangareva, mihi | 47 29 USM tata ; 6,7,7,7 | 17
singularis. Dutch Papua, mihi| 62 | 27-30| 72 | Saran i 7,8,8,8 | 34

Olindias singularis Browne.
Olindias singularis Browne, : 04, p. 737, pl. 56, fig. 2, pl. 57, fig. Z.
Plate 4, Fig. 1; Plate 31, Figs. 1-10; Plate 32, Fig. 8.

Mangareva Harbor; surface; 23 specimens, 16 to 36 mm. in diameter.

The general form of this graceful species, as seen in side view, and the
extent of the gonads, are shown in the photograph reproduced on Pl. 4,
fig. 1. In all structural features, except for the arrangement of the otocysts,
it so closely resembles O. phosphorica that no extended account is necessary
here. Browne was unable to find any sucking pads on the primary ten-
tacles in the Maldive specimen, and has therefore raised the question
whether Olindias does actually possess such organs; but inasmuch as the
claw-like terminations of the primary tentacles which he describes undoubt-
edly correspond to the structures interpreted as suckers by other authors,
and which occur in the present specimens (Pl. 31, fig. 8), the distinction
is apparently one of definition rather than of observation. To determine
conclusively whether these terminal organs do exercise an adhesive func-

110 THE MEDUSAE. :

tion requires observations on living specimens. They do in O. phosphorica, a
phenomenon I have myself observed at Bermuda.

The presence or absence of basal bulbs on the secondary tentacles is
closely connected with the state of contraction of the latter. When the ten-
tacles are extended, their bases, which are free from nematocyst bands, are
pear-shaped, and of considerably larger calibre than the distal portions. In
a state of contraction, however, the filamentous, nematocyst-bearing portions
of the tentacles increase so much in thickness, corresponding to the decrease
in length, that the basal swelling may be entirely masked, and that region
may actually be of smaller calibre than the remainder of the tentacle.
Intermediate conditions are of course more numerous than either of these
extremes. Thus it is evident that the presence of basal bulbs is a less
important character than Browne’s single specimen might suggest; yet,
inasmuch as none of the numerous excellently preserved West Indian
specimens of O. phosphorica which I have examined show any trace of basal
enlargements on even the most extended tentacles, it is not unreasonable
to retain this feature as one of the distinctive characters of O. singularis.

The secondary tentacles terminate in nematocyst knobs (PI. 31, fig. 7).
The finer structure of the two types of tentacles has been fully described by
Goto (: 03).

The number of otocysts is an important specific character in this form.
In the small specimens, 16-17 mm. in diameter, there is usually only one in
connection with each of the primary tentacles. In larger specimens, how-
ever, more of them are paired. In the largest specimens, 30-36 mm. in
diameter, single and paired otocysts are in the proportion of about four to
one (Pl. 31, fig. 4). When but a single otocyst is present at the base of
a primary tentacle it usually lies in the plane of the tentacle root (PI. 31,
figs. 3-5); and though there is some irregularity in this respect, I have
never seen a single otocyst lying at one side of the base of a tentacle. The
numerical condition of the otocysts is to be interpreted as phylogenetically
more primitive in O. singularis than in O. phosphorica; for while all authors
agree that in adults of the latter species the otocysts are invariably pared,
Mayer (: 04) has found that in the young they first appear singly, opposite
the bases of the primary tentacles. Each otocyst may contain either one or
two spherical otoliths (Pl. 31, fig. 10).

Gonads. —In the largest specimens the gonads, which first appear near
the ring canal, and with increasing development extend centripetally, occupy

=

LIRIOPE. 1a

the distal half of the radial canals. Since in O. phosphorica, in an advanced
stage, the gonads occupy nearly the entire length of the canals, it is possible
that the extent of these organs may afford another specific character,

The number of blind centripetal canals increases rather irregularly with
growth, as Mayer (: 04) has described for the young stages of O. phosphorica.
The largest number observed in any one quadrant was twelve, in the entire
bell, forty-six. Large specimens have, as a rule, from eight to eleven canals
per quadrant.

Color.— The gonads are reddish brown to brick red. Otherwise the
Medusa is colorless.

An interesting abnormality of this species (Pl. 32, fig. 8) has two separate
gastric cavities and no less than nine gonads; of these, four lie on the
radial canals, and the other five, which are much smaller, are situated on
blind canals which run outward from the gastric cavity.

Geryonidae Eschscholtz, 1829.

sens. em. Haeckel, ’79.

Trachomedusae with four or six radial canals; with blind centripetal
canals; with long gelatinous peduncle; tentacles in the young, of two kinds ;
gonads borne on the subumbrella.

Two genera are now generally recognized in this family, Liriope with
four, and Geryonia with six radial canals. Both of these are represented in
the collection.

Liriope Lesson, 1843.

sens. em. Maas, ’97.

Geryonidae with four radial canals.

I agree with Vanhdffen (: 02”) and Maas (:05) that of the various char-
acters which have been used to separate species in this genus, ¢.y. persistence
of embryonic tentacles, number of blind canals, form, size, color, and confor-
mation of the gonads, all but the last are subject to such great individual
variation as well as to such great changes with growth as to be wholly
useless. The shape of the gonads, however, seems more reliable, so long
as employed with due regard to the various stages through which these
organs pass with the progress of development.

The present collection contains two well-marked forms with regard to

the shape of the gonads; one with these organs primarily triangular, the

112 THE MEDUSAE.

other with them elongate, narrow, and oval. The series shows clearly that
Vanhéffen had good ground for maintaining that the forms, heart-shaped and
triangular, are but variations, often caused by contraction and preservation,
of a single ground form, and that this difference is not indicative of specific
divergence. I have no doubt that L. ¢etraphylia of the present collection is
identical with the form from the Pacific described by Maas under the name
L. rosacea, and of which he has given an excellent figure (97, taf. 3, fig. 7),
and with those recorded by him (:05) under the same name from the col-
lections of the “Siboga”; and at the same time there seems to be no stable
character to separate it from the specimens of Liriope with triangular
gonads from both Atlantic and Indian oceans, which Vanhdffen (: 02°) has
united under the name L. ¢tetraphylla. It is doubtful whether all the
species included by Vanhiffen in the “tetraphylla” group, particularly
LL cerasus, L. eurybia, and L, bicolor, really belong there, since in the form
of the gonads they suggest close affinity with L. seutigera.

Maas (:05) distinguishes three varieties in the “Siboga” collection, —
L. tetraphylla with ovoid, L. rosacea with triangular, and LZ. compacta with rhom-
boid gonads, but inasmuch as the present series shows all gradations between
the two extremes, there is good reason to believe that these represent
merely three successive stages in the development of a single species.

I am puzzled to find any satisfactory identification for the second species
contained in the collection, that with narrow oval gonads; and since an
incorrect identification is worse than none, because it may prove misleading
to students of the geographic distribution of this troublesome genus, I hesi-
tate to assign any specific name to it.

Liriope tetraphylla Chamisso.

Geryonia tetraphylla Chamisso, ’20, p, 357, taf. 27, fig. 2.

Liriope tetraphylla Gegenbaur, ’56, p. 257; Vanhoffen, : 02, p. 82; Maas, :05, p. 61.
Liriantha tetraphylla Haeckel, ’79, p. 286.

Xanthea tetraphylla L. Agassiz, 62, p. 365.

Liriope crucifera Haeckel, ’79, p. 290.
Geryonia rosacea Eschscholtz, ’29, p. 89.
Liriope rosacea Gegenbaur, ’56, p. 257; Maas, 97, p. 26, taf. 3, figs. 7, 8; :05, p. 62)

taf. 9, figs. 68, 59.
Glossocodon liitkenii Haeckel, ’79, p, 293, taf. 18, fig. 6.

Liriope litkeni Vanhoffen, : 02, p. 79.
Liriope compacta Maas, ’93, p. 37, taf. 3, fig. 77; : 05, p. 62, taf. 9, figs. 55-57.
Glossocodon agarious Haeckel, ’79, p, 293.

Liriope agaricus Vanhoffen, : 02>, p, 79.

LIRIOPE TETRAPHYLLA. 113

The synonymy given above seems to me fairly well established. It is
probable that the following names should also be added, but their identity is
somewhat less assured :— L. appendiculata Forbes, L. conirostris Haeckel,
L. cerasiformis Lesson, and L. mucronata Gegenbaur. The identity of L.
hyalina Agassiz and Mayer (’99), and of Z. indica, and L. hemisphericus
Bigelow (:04), which, as Maas (:05) has pointed out, are probably not
good species, cannot be settled because of the immature condition of their
gonads; it is probable, however, that they likewise belong here.

Plate 3, Figs. 6, 7; Plate 4, Figs. 2, 3.

Station 4574 ; 300 fathoms to surface; 3, small.

Station 4575; surface.

Station 4587; 300 fathoms to surface; several, small.
Station 4588 ; surface ; several, early stages.

Station 4592; surface; many small specimens.

Station 4596; surface ; 3, 5-10 mm. in diameter.

Station 4605 ; 300 fathoms to surface.

Station 4607; 300 fathoms to surface; several, small.
Station 4609 ; 300 fathoms to surface; 1, 2 mm. in diameter.
Station 4611; surface; swarm; large specimens and several early stages.
Station 4613 ; 300 fathoms to surface ; 2, fragmentary.
Station 4634 ; 300 fathoms to surface.

Station 4638; 300 fathoms to surface.

Station 4640; surface; several, 5-10 mm. in diameter.
Station 4643 ; surface ; 3 specimens, large, L. rosacea stage.
Station 4644; surface ; several.

Station 4648 ; 300 fathoms to surface ; several.

Station 4655; surface ; early stages.

Station 4657; surface ; several small specimens.

Station 4659; surface ; 3.

Station 4661; surface; 3 large specimens, L. rosacea stage.
Station 4663 ; surface ; swarm, various sizes.

Station 4664; surface ; 2 specimens, gonads just appearing.
Station 4665; surface; several.

Station 4667; surface; several.

Station 4667 ; 800 fathoms to surface.

Station 4669; surface; several.

114 THE MEDUSAE.

Station 4670 ; in trawl, from 320 fathoms; 1, fragmentary.

Station 4671; surface ; swarm, L. compacta stage.

Station 4673; 300 fathoms to surface.

Station 4673; surface; 2 large specimens, L. compacta stage.

Station 4673 ; 300 fathoms to surface ; 2.

Station 4680; surface; 1 specimen.

Station 4682; surface; 2 specimens.

Station 4702; surface; 2 specimens.

Station 4708 ; surface ; 6 specimens.

Station 4710; surface ; swarm, ZL. rosacea stage.

Station 4712; surface; several.

Station 4714 ; surface; 1 large specimen, L. rosacea stage.

Station 4716 ; surface ; 2 specimens.

Station 4718; surface; 1, fragmentary.

Station 4724 ; 300 fathoms to surface; 1, 20 mm. in diameter.

Station 4735; surface ; 2 specimens.

Station 4741; surface ; 1 specimen.

Acapulco Harbor; surface; many specimens, early stages and L. rosacea
stage.

The collection contains a series showing different stages in the development
of the gonads. The commonest condition, and one which from its resemblance
to the figures of Eschscholtz (29, taf. 11, fig. 2) and Maas (97, taf. 3,
fiz. 7), we may term the L. rosacea stage, is represented in the photograph (PI.
3, fig.7). In a majority of cases the triangular form of the gonads showed
clearly; but in a few instances, apparently as the result of muscular con-
traction, the gonads are heart-shaped, the basal border being more or less
deeply incised. The occurrence of a complete series connecting the two
forms demonstrates that Vanhiffen (:02°) was correct in believing them
to be merely variations of one type. I never, however, observed truly ovate
gonads except in the ease of very small individuals (PI. 4, fig. 3). It is most
interesting that the collection contains a number of specimens showing in a
typical degree the form of gonads believed by Maas (’93, : 05) to be charac-
teristic of L. compacta, in which these organs are rhomboid, truncate, and in
contact with one another; but since these were invariably the largest indi-
viduals, and since I found every conceivable grade between slightly truncate
triangular gonads to pentagonal ones of an even more pronounced form than
is shown in the photograph (PI. 3, fig. 6), it seems to me clear that the latter

LIRIOPE. Tas

is merely the final condition of the former and therefore deserves no recogni-
tion in nomenclature.

The gonads in very small specimens are ovate (Pl. 4, fig. 3), such as are
believed by Maas to characterize the species L. tetraphylla; but this is only
a transitory stage, for with growth the gonads broaden at their basal end,
while remaining of about the same breadth at the distal end,—a change
resulting in the attainment of the triangular form. An interesting feature
connected with the growth of the gonads is that the radial canal distal to
the sex organ is very much broader than it is proximal to the latter.

This character, as well as the form of the gonads, separates L. tetraphylla
from the second species of Liriope in the collection, and it is because of the
form of the canals (broadest at their distal ends) that I have included in
L. tetraphylla such larval stages as that represented on PI. 4, fig. 2.

The series shows clearly that the number of blind canals per quadrant is
of no taxonomic significance, for although seven seems to be the normal final
number, large specimens may have fewer, there being much variation in this
respect.

The color is variable ; most specimens are colorless, but in others the
gonads and manubrium are yellowish.

L. tetraphylla seems to be a typical oceanic species; it has, under its
various synonyms, been recorded from the tropical and subtropical waters
of all oceans. It occurred regularly over the entire area traversed by the
* Albatross.”

Liriope species ?

Station 4571; 300 fathoms to surface ; various stages,
Station 4575; surface.
Station 4605; 300 fathoms to surface.
Station 4634 ; 300 fathoms to surface.
Station 4638; 300 fathoms to surface.
Station 4640; surface.
Station 4648; 300 fathoms to surface.
Station 4664 ; surface.
Station 4710; surface.
Station 4712 ; surface.
The series contains all stages from the first appearance of gonads up to

specimens some 15 mm. in diameter. They are distinguished from JL.

Several specimens at each

station.

116 THE MEDUSAE.

tetraphylla by the narrow, oval form and distal position of the gonads, and
by the narrowness of the radial canals. In all the specimens, moreover, the
gelatinous substance is thinner and softer than in L. ¢etraphylla, but whether
this can be considered a specific character is doubtful.

Geryonia Péron et Lesueur, 1809.

Geryonidae with six radial canals.

Like the collections of most of the previous deep-sea expeditions, that of
the “ Albatross’? contains very few specimens of this genus compared to the
vast numbers of Liriope, —a fact interesting because the two genera are
now known to be of parallel distribution in the warmer waters of all oceans.
I follow Vanhiéffen (: 02>) in referring the present specimens to the oldest
species, G. proboscidalis Forskal. Probably, as he suggests, the number of
centripetal canals per sextant will prove to be an important specific char-
acter, in which case G. wmbella Haeckel with nine, and G. giltschii Haeckel
with eleven, must be distinguished from G. probdoscidalis with seven. But
whether G. wmbella and G. giltschii represent two good species, or only a single
one, cannot be determined without an examination of extensive material.
It is certain that the slight differences in form, size, shape of the gonads, and
color, which have been used as the bases of specific distinctions in this genus,
merely indicate different stages in growth.

Geryonia proboscidalis Forskal.

Medusa proboscidalis Forskal, 1776, p. 108, taf. 36, fig. 7.

Geryonia proboscidalis Eschscholtz, ’29, p. 88; Haeckel, ’79, p. 295; Vanhdéffen, : 02, p. 85.
Dianaea proboscidalis Lamarck, ’16, p. 505.

Liriope proboscidalis Lesson, 743, p. 331.

Leuckartia proboscidalis L. Agassiz, ’62, p. 364.

Leuckartia brevicirrata Haeckel, ’64”, p. 462.

Geryonia hexaphylla Brandt, ’38, p. 389, taf. 18.

Carmarina hexaphylla Haeckel, ’79, p. 298.

Geryonia conoides Haeckel, ’64”, p. 466.

Geryonia fungiformis Haeckel, ’64”, p. 465.

Carmarina fungiformis Haeckel, ’79, p. 297.

Geryonia umbella Haeckel, 64°, p. 464.

Geryonia hastata Haeckel, ’64", p. 327.

Carmarina hastata Haeckel, ’79, p. 297.

Geryones elephas Haeckel, ’79, p. 294, taf. 18, fig. 7.

? Dianaea endrachtensis |-gaberti] Quoy et Gaimard, ’24, p. 566, pl. 84, fig. 2.
? Dianaea gaberti Blainville, 34, p. 289, pl. 34, fig. 2.

? Hirene endrachtensis Eschscholtz, ’29, p. 94.

? Orythia viridis L. Agassiz, ’62, p. 363.

? Geryonia dianaea Haeckel, ’79, p. 295.

AGLAURA. a Lily

Station 4574; surface ; 1 specimen, with only five radial canals.

Station 4681 ; 300 fathoms to surface ; 1 very fragmentary specimen.

Station 4707; surface ; 1 specimen, 35 mm. in diameter.

Station 4740 ; 300 fathoms to surface; 1 specimen, 40 mm. in diameter.

All of these specimens have seven blind canals per octant, and the
gonads are lanceolate in outline. A surface form, from the warm regions
of all oceans.

Trachynemidae Gegenbaur, 1856.
(Including Aglauridae Haeckel.)

Trachomedusae with eight radial canals; without blind centripetal canals ;
with numerous tentacles, of either one or two kinds, but arranged in a
single series; with or without gelatinous peduncle; gonads either linear
or pendent.

Some confusion has been caused to students of this family by the diver-
gent views and accounts which have been published of the genera Penta-
chogon and Homoeonema, both of which were originally described by Maas
(793) from the collections of the ‘‘ Plankton ” expedition. Later studies of
the same author (: 05, : 06°) demonstrated that the species which he united
under Homoeonema belong to two different families, and that since the type
species, H. platygonon, is a halicreid, the name Homoeonema must be removed
to the Halicreasidae. This left the remaining species without any generic
name; to remedy this deficiency Maas (: 06") has proposed Isonema. Unfor-
tunately this name is already preoccupied by a genus of Mollusca, so that
the generic name Arctapodema proposed by Dall (: 07) must be used, if the
two species in question, Homoeonema amplum Maas and H. maerogaster Van-
hiffen, are to be separated generically from Pentachagon, as both Maas and
Vanhiffen believe is necessary.

Aglaura Péron et Lesueur, 1809.

An examination of considerable series of this genus from the Atlantic
as well as from the Pacific has convinced me that my former grouping of
the species (: 04, p. 257) was erroneous, and that Maas and Vanhéffen are
no doubt correct in maintaining that neither the form of the gonads nor
the length of the peduncle, which I believed to characterize A. cefagona,
are of any taxonomic significance in this genus. Vanhéffen (: 02”) main-

118 THE MEDUSAE.

tains that all described forms of Aglaura in reality belong to but one
species, A. hemistoma. According to Maas (: 05, : 06°), however, A. pris-
matica, described by him (’97) from the Gulf of Panama, and since recorded
by Agassiz and Mayer (’99, :02) from the Fiji Islands and Tropical Pacific,
as well as by himself from the collections of the “Siboga” and from Am-
boina, is so well characterized by prismatic, octagonal outline, small size
(5-4 mm. high by about 3 mm. broad) and early appearance of the gonads,
as to be worthy of recognition. Since the octagonal outline is considered
by Maas (: 05, p. 58) the most distinctive character of A. prismatica I studied
living material with especial care and found that the outline is variable ; for
though most of the specimens were nearly circular in cross section, a few
were distinctly prismatic; and these conditions are retained after preser-
vation. Because of this variation I believe that this character is no more
important than the general outline of the bell, which is well known to
be subject to great diversity in this genus in different states of muscular
contraction.

I have been able likewise to test the supposed difference in time of
appearance of the gonads on specimens both from the Atlantic and from
the Pacific. According to Maas (: 05) the Atlantic (Mediterranean) species
shows no gonads until about 3 mm. high; but I have observed gonads
(spherical) in a specimen from the West Indies not more than 1.5 mm.
high; while in several specimens 2.5-3 mm. high they were already large
and sausage-shaped. This character, then, is no doubt variable, as Maas
suggests (:05, p. 59) and cannot be considered as separating an Atlantic
from a Pacific form.

Since I am unable to find any constant characters distinguishing the
present specimens from others from the West Indies, I refer them to
A. hemistoma ; and inasmuch as many of the specimens were taken near
the type locality of A. prismatica, I see no reason to retain the latter
longer as a distinct species, or even variety. In all probability the present
series is specifically identical also with the specimens recorded by Agassiz
and Mayer (: 02, p. 150) as A. prismatica, and stated by them to be generally
distributed over the tropical regions of the Pacific; but which, according
to their earlier figure (99, Pl. 4, fig. 13), are circular, not prismatic, in
outline. Comparison shows that the specimens recorded by me (: 04) from
the Maldives as A. prismatica are also identical with the present series.

AGLAURA HEMISTOMA. 119

Aglaura hemistoma Péron et Lesueur.

Aglaura hemistoma Péron et Lesueur, 1809, p. 351; Haeckel, ’79, p. 275, taf. 16, figs. 3, 4 ;
Vanhoffen, : 02>, p. 78.

Agilaura peronii Leuckart, 756, p. 10, taf. 1, figs. 5-7.

Aglaura nausicaa Haeckel, ’79, p. 274, taf. 16, fig. 7.

Aglaura laterna Haeckel, ’79, p. 274, taf. 16, fig. 2.

Aglaura hemistoma var. nausicaa Maas, ’93, p. 26.

Aglaura prismatica Maas, ’97, p. 24, taf. 3, figs. 4,5; :05, p. 58; Agassiz and Mayer,
99, p. 165, pl. 4, fig. 13 ; Bigelow, : 04, p. 257.

Aglaura octagona Bigelow, : 04, p. 257, pl. 2, fig. 9.

Aglaura vitrea Fewkes, ’82, p. 277, pl. 7, fig. 10.

? Lessonia radiata Eydoux et Souleyet, ’52, p. 643, pl. 2, fig. 16.

? Aglaura radiata Haeckel, ’79, p. 276.

Plate 2, fig. 6.

Station 4580; 300 fathoms to surface.
Station 4583 ; 300 fathoms to surface.
Station 4587; 300 fathoms to surface.
Station 4588 ; surface.

Station 4594; 300 fathoms to surface.
Station 4596; surface.

Station 4598; 300 fathoms to surface.
Station 4607 ; surface.

Station 4609; 300 fathoms to surface.
Station 4611; surface.

Station 4613 ; 300 fathoms to surface.
Station 4615; surface. Several specimens at each
Station 4638; 300 fathoms to surface. station.
Station 4646; 300 fathoms to surface.
Station 4657; 300 fathoms to surface.
Station 4659; 300 fathoms to surface.
Station 4661; surface.

Station 4663; 300 fathoms to surface,
Station 4664; surface.

Station 4665; 300 fathoms to surface.
Station 4667; 300 fathoms to surface.
Station 4669; 300 fathoms to surface.
Station 4671; 300 fathoms to surface.
Station 4673 ; surface.

120 THE MEDUSAE.

Station 4676; 300 fathoms to surface.

Station 4688; 500 fathoms to surface.

Station 4707; surface.

Station 4708; surface.

Station 4714; surface.

Station 4716 ; surface.

Station 4721; 300 fathoms to surface.

Station 4733; surface.

Station 4734; 300 fathoms to surface.

Station 4741; surface.

The specimens vary considerably in outline, and in the proportion be-
tween breadth and height. In life most of them were about as high as broad,
as figured by Mayer (: 00°); but when preserved many of the specimens con-
tract so strongly as to take on a very tall, narrow outline (Pl. 2, fig. 6).
The great majority are circular in cross section ; a few, however, show, more
or less distinctly, the octagonal outline thought by Maas to be characteristic
of A. prismatica. Since, however, I have seen the same prismatic form in
a few specimens from the West Indies, it cannot be supposed to indicate
a geographic race. The largest specimen measures (preserved in formalin)
6 mm. high by 4 broad, dimensions approaching those of Atlantic speci-
mens, and considerably greater than those of any Pacific Aglaura previously
recorded. The greatest number of tentacles was about eighty-five, in the
specimen just mentioned, and since there is no reason to suppose that
this is the maximum, it is not unlikely that Pacific as well as Atlantic
specimens (Haeckel, ’79, Vanhiffen : 02) may occasionally have as many
as one hundred tentacles. The great majority of the specimens are from 3-4
mm. high and have from forty-five to fifty-five tentacles. Specimens about
1.5 mm. high have only about thirty.

Gonads. — In a specimen 1.5 mm. high the gonads are already visible as
minute spherical swellings at the point of junction of peduncle with manu-
brium ; a condition corresponding, as noted above, to that of an Atlantic
specimen of about the same dimensions. In a specimen 2 mm. high by
about 2 mm, broad they have already attained the “sausage” shape
characteristic of later stages.

In the smaller specimens the peduncle is very short, but in the larger
ones is almost as long as half the bell height. I observed no specimens
with the extremely long peduncle which I have recorded for two individuals

AGLANTHA. 121

=

from the Maldive Islands (:04) under the name A. octagona. There are
eight otocysts.

The specimens were all colorless.

The present captures, together with those already recorded by Agassiz
and Mayer (’99, :02), show that Aglaura hemistoma occurs commonly over
the entire Tropical Pacific. It is already known from both sides of the
Atlantic, both Tropical and subtropical, from the Gulf Stream, from the
Gulf of Mexico, the Mediterranean, the Indian Ocean, and from the Ma-
laysian region (A. prismatica Maas, : 05, : 06°). Thus it is an inhabitant of
the warmer regions of all oceans. It is unknown, however, in cold seas.

Aglantha Haeckel, 1879.

Trachynemidae with long peduncle ; the gonads situated on the oral wall
of the subumbrella surface, xof on the peduncle with either four or eight
otocysts.

This genus has recently been revised by Maas (: 06"), to whose work I
refer the reader for a full account of its rather confused synonymy. From
his studies, as well as from those of Browne (’97), Chun (’97), and Vanhiéffen
(97), it is now clear that it contains at least two well-defined species, A. digi-
tale Fabricius and A. rosea Forbes, of rather different geographic range. The
first of these, distinguished by large size and by the possession of only four
otocysts, is of circumpolar distribution (Chun, 97). Within it three geo-
graphic varieties, A. occidentalis (Maas, 93), A. digitale, and A. camtschatica
(Brandt, 38; Birula, 96), can be distinguished.

A. digitale occurs throughout the arctic zone of the Atlantic, A. oceidentalis,
in the northwestern Atlantic, from the Banks of Newfoundland south at least
as far as the northern margin of the Gulf Stream (A. Agassiz, 65; Hargitt,
: 05°), and A. camtschatica, so far as is known, only in Behring Sea and on the
northwest coast of America. A. rosea Forbes, with eight otocysts (Browne,
97), is a much smaller species. The recently described A. conica (Har-
gitt, :02) is apparently a synonym of this form, which is of boreal or
temperate occurrence, being known from the British coast, Heligoland
(Hartlaub, under the name A. digitalis), coast of New England (Hargitt),
and from Norway, where its range overlaps that of A. digitale. Up to the
present time the genus has been known only from northern, if not actually
subarctic regions. But since the “ Albatross” collection contains a consider-

122 THE MEDUSAE.

able series of the genus, this range must now be extended to the Tropical
Pacific.

Unfortunately the otocysts, the one character of greatest importance, are
destroyed in all the present specimens, and therefore they might equally
well be referred either to A. digitale or to A. rosea so far as this character
is concerned. Their size, however, suggests that their closest affinity is with
A, digitale; but inasmuch as they are distinctly smaller than adults of the
latter, they probably belong to a new variety of that species.

Aglantha digitale var. intermedia, var. nov.
Plate 29, figs. 4-10.

Station 4583; 300 fathoms to surface ; 2 specimens.

Station 4605; 200 fathoms to surface; 1 specimen.

Station 4609; 300 fathoms to surface; 4 small specimens.

Station 4613; 200 fathoms to surface ; 3 specimens.

Station 4638; 300 fathoms to surface ; 5 specimens.

Station 4652; 200 fathoms to surface; 5 specimens.

Station 4652; 400 fathoms to surface; 2 specimens.

Station 4659; 300 fathoms to surface; 1 very small specimen.

Station 4669; 300 fathoms to surface ; 3 specimens.

Station 4671; 300 fathoms to surface; 8 specimens, Type.

Station 4673 ; 300 fathoms to surface ; 1 specimen.

Station 4676; 300 fathoms to surface; 1 specimen.

In general form, and in the presence of a gelatinous apical proportion
the specimens agree very closely with the various accounts of A. digitale.
The outline varies, largely depending upon the state of contraction of
the muscular subumbrella, the bell being either broad, or narrow and
constricted. The largest specimen is about 14 mm. in diameter by about
15 mm. high, the smallest (Pl. 29, fig. 9) only 2.5 mm. high. In the large
specimens there are from eighty to ninety tentacles. In the smallest there
are only about thirty-five. This number is rather larger than Agassiz (65)
and Vanhoffen (97) have observed in A. digitale at corresponding stages, and
it may prove to be a character of specific significance. In all the speci-
mens the tentacles are broken short off.

In the smallest specimens, as A. Agassiz (65) has observed, the short manu-
brium hangs directly from the subumbrella surface (Pl. 29, fig. 9). With

TETRORCHIS. 123

advancing growth, however, the gelatinous peduncle develops, becoming
very prominent in adults (Pl. 29, fig. 4). The manubrium likewise grows
longer, until it is finally about as long as the peduncle, but as its length
is variable, this character is probably not of taxonomic importance. The
mouth opening is simple (Pl. 29, fig. 6); but when it is closed the manu-
brium is folded in such a way that there appear to be four long lips
(PI. 29, fig. 7). The peculiar course of the radial canals on the peduncle
(Pl. 29, figs. 6, 7) is apparently constant.

The long, sausage-shaped gonads, well developed in the larger speci-
mens, hang from the canals at the apex of the bell cavity. The smallest
specimens show no trace of them, and they are first visible as minute
spherical swellings in specimens about 5 mm. high (PI. 29, fig. 10). The
entire subumbrella surface, as well as the velum, is very muscular.

Color. —The Medusa is colorless except that the entodermic lining of
the manubrium, visible only when the distal portion of the manubrium
is everted (Pl. 29, fig 8), is pink.

This race is decidedly larger than A. rosea, especially at the time that the
gonads appear. The rather larger number of tentacles seems to separate it
from the previously known varieties of A. digitale.

The present captures indicate that in the tropics Aglantha belongs to
the intermediate, not to the surface fauna. This is a marked divergence
from the northern forms, which are frequently recorded from the surface,
though apparently at times penetrating to a considerable depth (Guen-
ther, :03). Off the coast of Greenland, according to Vanhiffen (97), the
young live at a depth of thirty or more metres, and rise to the surface
with the formation of the gonads.

The very broad horizontal distribution of the present series from 13° S.
to 20° N. is also of importance, for this considerable extension northward
in the intermediate zone suggests a possible overlapping with A. digitale
var. camtschatica, which is common on the surface in the Gulf of Georgia, in
latitude 48° N. (A. Agassiz, ’65).

Tetrorchis, gen. nov.
Trachynemidae without peduncle ; with four gonads attached to as many
radial canals near their junction with the ring canal.
This genus is established to include a single species, apparently new,

which is distinguished from all other Trachynemidae, to which family it

124 THE MEDUSAE.

undoubtedly belongs, by the number and position of the gonads, as well as
by a peculiar radial arrangement of the tentacles described below.

Tetrorchis erythrogaster, sp. nov.
Plate 29, figs 1-3.

Station 4665; 300 fathoms to surface; 1 specimen.

Station 4675; 300 fathoms to surface; 1 specimen.

Station 4689; 300 fathoms to surface; 1 specimen.

Station 4716; 600 fathoms to surface; 1 specimen.

Station 4717; 800 fathoms to surface; 1 specimen, Type.

Station 4721; 500 fathoms to surface; 1 specimen.

All the specimens are of about the same size, some 10-12 mm. in diame-
ter by about 8 mm. high; and all have large gonads. They are in fair
condition, although the margins of all are somewhat battered.

Bell. — The bell is about two thirds as high as broad; the gelatinous
substance very thick apically, though not forming a definite projection,
but thinner toward the margin. On account of this thickness the bell
cavity is shallow (Pl. 29, fig. 1).

Tentacles. — The tentacles, all of which are solid, are interesting characters
of the species. The four opposite the four fertile radial canals are very stout
(Pl. 29, figs. 1, 2), and provided with prominent entodermal roots. These
are the only perradial tentacles, for the remaining ones, which are much
smaller than those just described though resembling them structurally, have
no connection with the sterile canals. These small tentacles vary in num-
ber, but there are usually about three of them per octant. In all the speci-
mens the tentacles are broken short off, only the stumps remaining. In the
allied genus Persa, as well as in Aglaura and Aglantha, the tentacles are
more numerous and all of one kind, the differences in size in these genera
being without any radial significance such as connection with the radial
canals, but merely the expression of differences in age. I have been un-
able to find any otocysts; but from the condition in other Trachynemidae
it seems certain that some such structures are normally present in this
species, and that their apparent absence is due to poor preservation.

Gastrovascular system. —'The proboscis, which is cylindrical, about as long
as the depth of the bell cavity and with four inconspicuous lips, hangs di-
rectly from the subumbrella surface without any trace of peduncle (Pl. 29,

AMPHOGONA. 125

fig. 1). The four fertile radial canals are stout and easily traced; but the
four sterile ones are, in all the specimens, less well defined, and, though
well preserved proximally, can hardly be traced at all as they approach
the ring canal. The constancy of this appearance suggests the possibility
that they may lack a well-developed lumen; but this cannot be determined
except on better material than the present.

Gonads. — These, four in number as stated, and located on four of the
radial canals, about two thirds of the length of the latter from the oral
pole, are sausage-shaped and attached to the canal by only a narrow stalk
(Pl. 29, fig. 2). They are about 1 mm. in length, and are well developed in
all the specimens. The four sterile canals show no trace whatever of
gonads.

Color. — This species exhibits a very characteristic and unusual pigmen-
tation, the entire manubrium being brilliant carmine, except for the margins
of the four lips, which are opaque white (Pl. 29, fig. 7). The remainder of
the Medusa is colorless.

This interesting form no doubt belongs to the intermediate fauna, since
it was never taken on the surface.

Tetrorchis is evidently closely allied to Persa, from which it differs only
in having four instead of two gonads, and in the smaller number and
peculiar radial arrangement of the tentacles. It is true that Haeckel (’79,
taf. 16, fig. 12) figures a short gelatinous peduncle for P. lucerna Haeckel,
but inasmuch as there appears to be no such structure in P. incolorata
(McCrady, 57, pl. 12, fig. 3), its presence or absence is not of much taxo-
nomic value in that genus. ‘In the number of gonads (four) it agrees with
Stauraglaura, but the location of these organs near the distal ends of the
radial canals, instead of near the junction of the latter with the manubrium,
as well as the peculiar radial arrangement of the tentacles, seems to me
sufficiently important to indicate separate generic rank. The type species
is distinguished from all other Trachomedusae by these two features, as
well as by the absence of any gelatinous peduncle and by its characteristic

coloration.

Amphogona Browne, 1904.

Trachynemidae with peduncle; with numerous tentacles all alike; the
eight gonads spherical, pendant, borne on subumbrella near distal end of

radial canals ; bell low and saucer-shaped.

126 THE MEDUSAE.

Browne has already pointed out (: 04, p. 740) that Pentachogon apsteini
Vanhiffen, for which he has instituted this genus, is to be separated from
Agliscera, its closest ally, by the form of the gonads and of the bell, as
well as by the much more remarkable fact that the Maldive specimens
of P. apsteini were hermaphroditic. Inasmuch as hermaphroditism has never
been observed, so far as I can learn, in any other Trachomedusa, I
was of course particularly glad of the opportunity to test its occurrence
in a second series of A. apsteint from a different locality. The result of
this study, prosecuted on cross sections of the gonads, has been to show that
these Pacific specimens are not hermaphroditic, but follow the more usual
plan, all the gonads of any given individual being either male or female.
The explanation of this remarkable dimorphism in different lots of this one
species must be sought on more extensive material from various regions.

Amphogona apsteini Vanhoffen.

Pentachogon apsteini Vanhoffen, : 02», p. 65, taf. 10, fig. 78, taf. 11, fig. 28.
Amphogona apsteini Browne, :04, p. 740, pl. 54, fig. 5, pl. 55, fig. 5, pl. 56, fig. 7,
pl. 57, figs. 10-15.

Plate 2, Figs. 1,2; Plate 34, Figs. 12-15; Plate 45, Fig. 10.

Acapulco Harbor, February 28; surface; 6 specimens, from 2.5 mm. to
6 mm. in diameter.

Browne has given us such a good account of this species that I have but
little to add to his description, with which the present specimens closely
agree except for the gonads, as noted above.

The diameter of the largest specimen, 6 mm., is somewhat greater than is
recorded by Browne (4.25 mm.). In outline the living specimens were less
flattened, being about twice as broad as high (PI. 2, fig. 1), and slightly
conical. The gelatinous substance is thin, but rigid. In the large speci-
mens the peduncle hangs about to the bell opening, and is rather narrow
(Pl. 34, fig. 15).

Tentacles. — In the largest specimen, 6 mm. in diameter, there are about
sixty-four tentacles, usually eight per octant, though the number varies
somewhat. Browne has recorded seventy tentacles for a rather smaller speci-
men, so it is evident that as in most Trachynemidae the number is individ-
ually variable. In the smallest specimen, 2.5 mm. in diameter, there are

only about forty. All the tentacles are of one type, though, from their

RHOPALONEMA. 127

different sizes, evidently of different ages (Pl. 34, fig. 14), and in all the
specimens all of them are broken short off.

The club-shaped otocysts (Pl. 34, fig. 13; Pl. 45, fig. 10) have been well
described by Browne (: 04, p. 740, pl. 57, fig. 15). In a specimen 4 mm. in
diameter there are three otocysts each in six of the octants, and in the
smallest specimen apparently only one per octant. Vanhéffen (: (02°)
records two otocysts per octant in an individual 3.5 mm. in diameter. The
manubrium is short and barrel-shaped, the mouth surrounded by four
narrow, pointed lips (Pl. 34, fig. 15). The gonads, which are nearly spher-
ical, are attached to the radial canal only at a small area. This character,
clearly indicated in Browne’s figures (: 04, pl. 57, figs. 11, 13), might easily
be overlooked on surface views on account of the small size of the gonads,
but is easy to demonstrate on serial sections. In the adult all gonads are
of about the same size, but in the small specimens small and large gonads
alternate, as Vanhiffen observed (: 02”, taf. 10, fig. 18); but since in any
of our specimens all gonads are of one sex, this alternation is not con-
nected with hermaphroditism, as appeared to be the case in the specimens
described by Browne (: 04).

The specimens were entirely colorless.

Amphiogona apsteini is a surface form, It has previously been recorded
only from the Indian Ocean (Maldive Islands, Browne; west coast of
Sumatra, Vanhiéffen).

Rhopalonema Gegenbaur, 1856.
sens. em. Vanhdéffen (: 02").

Trachynemidae with thirty-two tentacles, of two kinds, 7. e. radial clubs,
and inter- and adradial cirri; with enclosed otocysts; without peduncle.

The above definition is that of Vanhéffen (: 02°, p. 59), who has shown
very clearly that the species of Marmema enumerated by Haeckel (’79), and
the majority, at any rate, of those of Trachynema, represent nothing more
than two successive stages in the development of Rhopalonema.

The present collection contains two well-defined species of the genus, one
a surface, the other an intermediate form. ‘The first of these is no doubt
identical with the species described by Vanhoffen (: 02”) and Maas (98, :05)
under the name R. velatum Gegenbaur, and with specimens from the
West Indies in the Museum of Comparative Zoilogy. I believe that it is
also identical with the specimens from the Bay of Biscay identified by

128 THE MEDUSAE.

Browne (:06) as 2. coeruleum Haeckel, as well as with Haeckel’s specimens
of R. coeruleum from the Canary Islands. It is to be distinguished by its
small size (8-10 mm. in diameter), by the form of the gonads, which are
cylindrical and occupy only the central third of the radial canals, and by the
number of otocysts, which never normally surpasses sixteen. Even this
number seems to be reached only in very large individuals, most specimens
having only eight. Another character on which Browne has laid stress, and
which I find very constant in the present large series is the presence of an
apical thickening or “top knot” of the gelatinous disc (PI. 2, fig. 8). This
character, although perhaps trivial, sharply distinguishes this species from
the ensuing one. Regarding the name to be adopted for this species, it
seems to me best to retain &. velatum. For although adult specimens were
first described as R. coeruleum by Haeckel (79), yet the individuals on which
Gegenbaur based his earlier account of R. velatum were sufficiently advanced
for specific determination.

I have no difficulty in identifying the second species with the R.
funerarium of Vanhiffen (: 02°), from his excellent figures. The “Siboga”’
specimens recorded by Maas under the name W&. coeru/eum Haeckel are
likewise identical with this form (Maas,: 05, p. 51). This species is dis-
tinguished from /. velatum by large size (30mm. in diameter), long gonads,
absence of an apical thickening, greater number (thirty-two) of otocysts, and
by the brilliant iridescence of its subumbrella surface. Maas doubts whether
this form can be identified with the very unsatisfactory figures given by
Quoy et Gaimard of Dianaea funerarium, and therefore includes it in R.
coeruleum Uaeckel, which he believes resembles it more closely than does
any other known species. To this identification Browne (: 06) objects
that the ‘ Siboga” specimens have very long gonads, and entirely lack the
apical “top knot,” so prominent in Haeckel’s figures (79, taf. 17, fig. 3).
Indeed there is little resemblance between the two except the bluish iri-
descence; and I believe, as already stated, that R. coerulewum Haeckel is in
reality a synonym of [?, velatum. Following this conclusion I shall retain for
the present species Vanhéffen’s name, 2. funerarium, dating it, however, from
Vanhiffen (: 02°), not from Quoy et Gaimard. This seems one of the cases
where it is unprofitable to endeavor to identify the specimens in question
with any of the older accounts, for, being an intermediate and not a surface
form, it is altogether probable that it had never been observed until taken

by the “Valdivia,” unless it may be identical with the poorly preserved speci-

RHOPALONEMA VELATUM. 129

mens of the “ Plankton” expedition described by Maas (93) under the name
R, striatum. Could this be shown to be the case, the name R. striatum should
be substituted for R. funerarium.

It is probable that all of the species referable to Rhopalonema which
have yet been described belong to either one or other of these two species.
So many of the names, e.g. all those referred by Haeckel to Marmema,
and the majority of those referred by him to Trachynema, were based
on larval stages or on poorly preserved material that the synonymy of the
species is difficult. The size and habitat of most of the described forms,
however, make it almost certain that they fall under R. velatum.

I have been able to satisfy myself by an examination of specimens that
this is likewise true of A. typicwm Agassiz and Mayer (: 02), supposed by
them to be identical with Homoconema typicum Maas (97), which, however,
belongs to a different genus; and also of the specimens from the Mal-
dive Islands, which I recorded under the same name (:04, p. 256). The
cease of R. typicum Hargitt (: 02) from the Gulf Stream must remain doubt-
ful, since Hargitt states (: 05°, p. 54) that it has numerous cirri between the
radial tentacles, a character showing that it certainly is not related to Maas’s

HH, typicum.

Rhopalonema velatum Gegenbaur.

Rhopalonema velatum Gegenbaur, ’56, p. 251, taf. 9, figs. 1-5 ; Haeckel ’79, p. 264;
Vanhoffen, : 02, p. 59, taf. 10, figs. 26, 28, taf. 11, fig. 32.

Rhopalonema coeruleum Haeckel, ’79, p. 264, taf. 17, figs. 3-6; Browne, :06, p. 172
(non Maas, : 05).

Rhopalonema polydactylum Haeckel, ’79, p. 265, taf. 17, figs. 7-71.

Rhopalonema typicum Agassiz and Mayer, : 02, p. 152, pl. 5, figs. 27, 22; Bigelow, : 04,
p- 256.

The following are undoubtedly young stages of this species : —

Trachynema octonarium Haeckel, ’79, p. 260.

Sminthea tympanum (et globosa) Gegenbaur, 756, p. 246, taf. 9, figs. 17, 18.
Marmema tympanum Haeckel, ’79, p. 262.

Sminthea globosa Keferstein und Ehlers, ’61, p. 89.
Marmema clavigerum Haeckel, ’79, p. 263, taf. 17, figs. Z,
Calyptra umbilicata Leuckart, ’56, p. 14, taf. 1, figs. 9, 10.
Rhopalonema umbilicatum L. Agassiz, *62, p. 366.
Marmema umbilicatum Haeckel, ’79, p. 263.

Marmema velatoides Maas, 93, p. 13, tai. 1, fig. 0.
9

2D
we

130

Station
Station
Station
Station

Station 4605 ;
Station 4611;

Station
Station
Station
Station
Station

4571;
4580 ;
4587 ;
4598;

4634;
4635 ;
4637 ;
4638 ;
4640;

Station 4644 ;
Station 4646 ;

Station
Station

4647 ;
4650;

Station 4652;

Station
Station

Station 4656 ;

Station

Station 4659;

Station
Station
Station
Station
Station
Station
Station
Station
Station
Station
Station

Station

Station 4687 ;

Station
Station

Station

A654 ;
4655 ;

4657 ;

4663 ;
4664 ;
4665;
4667 ;
4669;
4669 ;
4671;
4673 ;
4675;
4676 ;
4685 ;
4687;

4688 ;
4690;
4691;

THE MEDUSAE.

Plate 2, Fig. 8; Plate 45, Fig. 11.

surface ; 1 small specimen.

300 fathoms to surface ; 1 specimen.

300 fathoms to surface; 1 specimen.
surface ; 1 specimen.

300 fathoms to surface ; several small individuals.
surface ; swarm of large specimens.

300 fathoms to surface ; 2 specimens.
surface ; several.

300 fathoms to surface; several.

300 fathoms to surface - several.

surface ; several.

surface ; swarm of large individuals.

300 fathoms to surface ; 1 small specimen.
in trawl from 2,005 fathoms; 1 specimen.
300 fathoms to surface ; 1 specimen.

400 fathoms to surface ; 1 specimen,
surface.

surface.

surface.

surface ; 2 specimens.

300 fathoms to surface ; several.

surface; 1 specimen.

surface ; swarm of large individuals.

300 fathoms to surface ; 1 specimen.

300 fathoms to surface ; 1 specimen.
surface ; 1 small specimen.

300 fathoms to surface ; 1 small specimen.
300 fathoms to surface; 5 specimens.

300 fathoms to surface; several.

surface ; several.

300 fathoms to surface; 1 specimen.
surface ; several.

in trawl from 2,100 fathoms; 1 small specimen.
300 fathoms to surface ; 1 specimen.
surface ]

surface } at each several specimens.

surface |

RHOPALONEMA VELATUM. 131

Station 4695; 300 fathoms to surface; 1 specimen.

Station 4700; surface; 1 specimen.

Station 4702; surface; 1 specimen.

Station 4706; surface; 1 specimen.

Station 4710; surface; 1 specimen.

Station 4715; 300 fathoms to surface ; several.

Station 4715; 300 fathoms to surface ; 2 specimens.

Station 4716; surface; 1 specimen.

Station 4717; 300 fathoms to surface ; 1 specimen.

Station 4721; 300 fathoms to surface.

Station 4722; 300 fathoms to surface.

Station 4725; surface ; 2 specimens.

Station 4728; 300 fathoms to surface.

Station 4729; surface ; 1 specimen.

Station 4731; surface; 1 specimen.

Station 4732; 300 fathoms to surface; 1 specimen.

Station 4733; surface; 1 specimen.

Station 4734; 300 fathoms to surface ; 1 specimen.

Station 4736; 300 fathoms to surface; several.

Station 4737 ; 300 fathoms to surface ; several.

Station 4743 ; surface ; several specimens.

Most of the specimens have only sixteen tentacles (Pl. 45, fig. 11); a few
of the largest, however, 8-9 mm. in diameter, show the stumps of thirty-
two, as already noted by Vanhdffen (:02°) and by Browne (:06). In none
could I distinguish more than eight otocysts, although Browne has shown
that sixteen is probably the final number of these organs.

Rhopalonema velatun shares with Liriope tetraphylla the distinction of
being the most abundant Medusa of the expedition. It was previously
known to be very generally distributed throughout the warmer waters of
both Atlantic and Indian oceans; and the present collection, together with
specimens from the Hawaiian Islands and from Fiji shows that it is charac-
teristic of the entire Eastern Tropical Pacific. Although often taken in
vertical hauls, it is a typical surface form, there being no evidence that
it ever occurs below 100 fathoms (Browne, :06). It is restricted to warm

waters.

£32 THE MEDUSAE.

~Rhopalonema funerarium Vanhéffen (non Quoy et Gaimard).

Rhopalonema funerarium Vanhoffen, :02°, p. 61, taf. 9, fig. 2, taf. 10, fig. 17, taf. 11,
fig. $1.

Rhopalonema coeruleum Maas, :05, p. 51, taf. 10, figs. 67, 68 (non Haeckel, ’79).

? Rhopalonema striatum Maas, ’93, p. 15, taf. 1, fig. 3.

Station 4673; 300 fathoms to surface ; fragments.

Station 4707; 300 fathoms to surface ; 3 specimens; fragmentary.

Station 4713; 300 fathoms to surface; 1 specimen; fair condition.

Station 4715; 300 fathoms to surface; 1 large specimen; fragmentary.

Station 4719; 300 fathoms to surface ; 3 specimens.

Station 4724; 300 fathoms to surface; 2 specimens.

None of the present specimens are preserved well enough for me to
count the otocysts or tentacles, but the elongated shape of the gonads, the
general form and size, and the brilliant iridescence of the subumbrella all
indicate that they belong to R. funerarium. None of the specimens were
taken on the surface; a fact supporting the conclusion arrived at by recent
students of this species (Vanhiffen, :02°; Maas, :05) that it belongs to the
intermediate fauna. The localities at which it was taken all lie within the
course of the Humboldt Current. The geographic distribution of the species,
so far as yet known, parallels that of A. velatum.

Colobonema Vanhoffen, 1902.

Trachynemidae with tentacles all of one kind, thirty-two in number, of
which the eight perradial, the sixteen adradial, and finally the eight in-
terradial develop in succession. It is probable that there are no otocysts
in this genus.

The successive studies of Vanhéffen (: 02) and of Maas (:05) have given
us a good understanding of this interesting genus; and we must thank
Vanhiffen for a very beautiful figure of the type species, C. sericewm.
The present collection contains several specimens which are clearly iden-
tical with the “ Valdivia” specimens; also identical with them, according
to Browne (:06), is a series of this genus from the Bay of Biscay.
The case of the “Siboga” specimens is not quite so clear, since they all
possessed a much longer proboscis than Vanhéffen observed; but inas-
much as one large specimen, 39 mm. high, in the present series has a

proboscis over 10 mm. long, while in all the others it is very short indeed,

COLOBONEMA SERICEUM. 33

it is evident that this character is subject to considerable individual variation,
and is not of specific importance, as Maas has suggested (: 05, p. 53). Sinte
in other respects, 7. e. general form, form of the gonads, number of tentacles,
and color, the “Siboga” specimens agree with Vanhiffen’s account of C.
sericeum, they probably belong to that species.

Maas believes that Colobonema sericeum is identical with a Medusa from
the Gulf of California, described by him under the name Homoeonema
typicum (97, p. 22, pl. 3, figs. 1-3), and that the name C. typicum instead
of C. sericewn should therefore be employed. I agree with Browne, however
(:06), in thinking that the connection between these two forms is doubtful.
All recent examples show that the number of tentacles, 7. e. thirty-two,
and the type of their succession is one of the most constant characters
of Colobonema sericeum. In C. typicum, however, according to Maas’s original
figures, there are not only many more tentacles, but a variable number in
different octants (three to seven between every two radial canals). The
shape of the gonads, too, is different, for while in C. sericewm these are
linear, and occupy almost the entire length of the radial canals, in @.
typicum they are cylindrical. Maas believes that these differences are, at
least in part, due to the poor condition of the material from which @.
typicum was described, but they appear to me quite sufficient to indicate
specific difference.

Colobonema sericeum Vanhdffen.

Colobonema sericeum Vanhiffen, : 02”, p. 57, taf. 9, fig. 7, taf. 12, figs. 39-42; Browne,
: 06, p. 172.
? Colobonema typicum Maas, : (5, p. 53, taf. 10, figs. 62-65.

Plate 2, Figs. 4,5; Plate 45, Fig. 12.

Station 4646; 300 fathoms to surface; 1 rather fragmentary specimen.

Station 4655; 300 fathoms to surface ;1 specimen, fragmentary, 20 mm,
high.

Station 4661; 300 fathoms to surface ; 1 excellent specimen, 22 mm. high.

Station 4670; in trawl from 3,209 fathoms; fragments.

Station 4679 ; 300 fathoms to surface ; 1 excellent specimen, 35 mm. high.

Station 4715; 300 fathoms to surface ; 1 fragmentary specimen.

Station 4721; 300 fathoms to surface ; 1 specimen, 18 min, high.

Station 4743; 300 fathoms to surface ; 2 specimens, 10 and 39 mm. high.

134 THE MEDUSAE.

The general aspect of this species is shown in the photograph (PI. 2, fig.
5), and its color in Vanhéffen’s beautiful figure (: 02°, taf. 9, fig. 1). I was
unable to find any octocysts; and as I, like Vanhéffen, examined excellent
specimens in the fresh condition, with negative results, and since neither
Maas nor Browne were able to find any otocysts on preserved specimens,
it is probable that this genus actually lacks these organs. The specimens
corroborate Maas’s (: 05) statement that in the formation of the tentacles the
perradial appear first, then the adradial, and finally the interradial; indeed
even in large specimens the latter remain much the smallest (Pl. 45, fig. 12).
This type of succession is so unusual that it may well be considered of
generic significance.

This species has a more brilliant iridescence than any other Medusa with
which I am acquainted.

Colobonema sericeum is undoubtedly an intermediate form. It is one of the
few species which have been taken in closing nets, a single specimen being
recorded by Vanhiffen (: 02°) from the “ Valdivia” collection, from 820-500
fathoms. Its geographic range, so far as yet known, includes the north
Atlantic (Bay of Biscay, Browne); the Tropical Atlantic ; the south Atlantic
to 42° S. Lat.; the Indian Ocean (Vanhéffen); the Malay Archipelago
(Maas); and the Eastern Tropical Pacific.

Pectyllidae Haeckel, 1879.
Trachomedusae with numerous tentacles arranged in several rows; with
well-developed manubrium.
Only one member of this family, a species of the little-known genus
Crossota, is represented in the collection.

Crossota Vanhoffen, 1902.

Pectyllidae with numerous tentacles arranged in several continuous hori-
zontal rows, but not in groups; gonads borne on the upper umbrella portion
of the radial canals; without mesenteries.

This definition is essentially that given by Maas (: 06‘), who follows Van-
hiffen in pointing out the close resemblance of this genus to Pectyllis and
Pectis. It is, however, simpler than either, being easily distinguished from
them by the absence of mesenteries, as well as by showing no trace of a
radial grouping of the tentacles. The genus has so far been recorded only
from the collections of the “ Valdivia” Expedition and from Norway.

CROSSOTA BRUNNEA. 135

Vanhéffen distinguishes two species, C. brunnea, the type, and C. nor-
vegica, but the only distinction between the two is that the single speci-
men of C. norvegica “ist charakterisiert . . . bei geringerer Griésse, durch
weiter entwickelte Gonaden ” (Vanhoffen, : 02°, p. 76), and by a slightly
brighter red color than that of C. brunnea, distinctions which Vanhéffen himself
admits are “nicht bedeutend.” His main basis for separating the two seems
to be their geographic distribution :— “ Weil ein Zusammenhang zwischen
den Tiefseegebieten, in denen die siidliche und die arktische Form vor-
kommen, nicht besteht und weil keiner unserer tiefen Vertikalnetzfiinge im
nordlichen Atlantischen Ocean uns ein Exemplar von Crossota lieferte”’
(Vanhiéffen : 02°, p. 76).

I must strongly protest against the use of supposed geographic isolation
as the basis for specific separation in cases like the present in which there are
no structural differences of sufficient taxonomic value to separate the two
forms. This practice may perhaps be of service to the ornithologist, though
this I doubt, but when applied to Medusae it is worse than useless. The
assumption that no connection exists between southern and arctic “ Tiefsee-
gebieten”’ is far from being proved. On the contrary, the distribution of
Atolla and of Periphylla, and the recent capture of Colobonema in the north
Atlantic suggest exactly the contrary, while evidence is continually being
adduced to show the general continuity, not isolation, of the distribu-
tion of intermediate organisms in general. Such a criterion might be of
service were isolation of oceanic areas established; but until the ranges of
the intermediate Medusae are better known it is not only valueless but
misleading. Therefore, I do not hesitate to include C. norvegica as a syn-
onym of C. brunnea, where it should remain, at least until some actual
divergence is detected between the two supposed species.

Crossota brunnea Vanhoffen.
Crossota brunnea Vanhoffen : 02, p. 73, taf. 9, figs. 77-13, taf. 12, figs. 84-38, 43, 47.

Crossota norvegica Vanhoffen, : 02”, p. 75.

Plate 2, Fig. 7; Plate 45, Fig. 9.
Station 4646 ; 300 fathoms to surface ; 3 specimens.
Station 4648; 300 fathoms to surface; 1 specimen.
Station 4655; 300 fathoms to surface; 1 specimen.
Station 4657; 300 fathoms to surface ; fragments.
Station 4663; 300 fathoms to surface ; 2 specimens.

136 THE MEDUSAE.

Station 4668; 300 fathoms to surface ; 2 specimens.

Station 4670; in trawl from 3,209 fathoms; 1 large specimen; frag-
mentary.

Station 4672; in trawl from 2,845 fathoms; 1 large specimen.

Station 4672; 400 fathoms to surface ; 1 specimen.

Station 4675; 300 fathoms to surface; 1 specimen.

Station 4676; 300 fathoms to surface ; 2 specimens.

Station 4716; 600 fathoms to surface; 1 fragmentary specimen.

Station 4721; 200 fathoms to surface; fragments.

Station 4722; 300 fathoms to surface; fragments.

Tcan add but little to the excellent description and beautiful figures
of this species given by Vanhiffen. The largest specimen in the series
measured 27 mm. in diameter and 20 mm. high; it had large gonads (PI. 45,
fig. 9). In searching for otocysts I was no more successful than Vanhiffen,
who has carefully studied the arrangement in rows of tentacles of various
ages. The high-arched bell, the sausage-like form of the gonads, the con-
siderable length of the proboscis, and the color are probably characters of
specific importance. The last is one of the most characteristic features of
this species. The entire subumbrella surface, gonads, and proboscis are
densely pigmented with deep reddish brown. Crossota brunnea was taken
by the “ Valdivia” in the Atlantic from the equator to 60'S. Lat., and in
the Indian Ocean. Under the name C. norvegica it is recorded also from
69° 13’ N. and 10° 40’ E. It undoubtedly belongs to the intermediate
fauna. I find no record of its capture in a closing net.

Halicreasidae Fewkes, 1886.
Halicreidae Vanhoffen (: 02>).

Trachomedusae with eight broad radial canals; with numerous tentacles,
of different sizes but all of the same structure and arranged in a single
series, each tentacle divisible into a soft flexible proximal and a. stiff,
spine-like distal region; with free sensory clubs; with neither peduncle
nor proboscis.

The successive studies of Vanhiffen (: 02”) and of Maas (: 05) have given
us a good idea of the general organization of these remarkable Medusae ;
but on account of the condition of their specimens neither of these authors
has been able to study the structure of the tentacles, which proves to be

one of the most important characters of the family.

HALICREASIDAE. 137

Vanhiffen distinguished two genera, Halicreas Fewkes and Haliscera,
basing the separation on the number of tentacles, Halicreas having more
than fifteen, Haliscera twelve or less per octant; but I agree with Maas
(: 05, p. 56) that a much more important character than the number of
tentacles is the presence or absence of the remarkable exumbral papillae.
If we employ this criterion the members of the family fall into two groups : —
on one hand the stem genus Halicreas with papillae, and on the other all spe-
cies without these structures. Maas believes that two genera should be distin-
guished for the species HZ. platygonon Maas, H. rotundatum Vanhiften, H. alba
Vanhiffen, H. conica Vanhioffen, and H. racovitzae Maas, according as their
gonads are proximal, or occupy the central one third of the radial canals ;
but the degree to which the positions of the gonads may change with age in
other families (Geryonidae, Petasidae) suggests that this character is of no
more taxonomic value than the number of tentacles; thus, all Halicreasidae
with eight canals, with the tentacles uniformly arranged, but without ex-
umbral papillae, may be included in a single genus. It seems to me that
according to the ordinary rules of nomenclature the name Homoeonema of
Maas must be adopted for this genus rather than Haliscera of Vanhoffen,
inasmuch as Maas has demonstrated by a fresh examination of the type
specimens of Homoconema platygonon, which he has designated as the type
species (: 06°, p. 3), is at least congeneric with the Haliscera alba of Van-
héffen. The position of the two species referred by Vanhéffen (: 02°) to
Homoeonema has already been discussed.

It is probable that the new genus Botrynema, recently described by
Browne (:08) from the collection of the ‘Scotia,’ in which the tentacles
are in groups, likewise belongs to this family.

All of these three genera of Halicreasidae have eight canals. There is,
however, one species in the present collection undoubtedly to be referred
to this family because of the structure of its tentacles and otocysts, but which

has twenty-eight canals; for this I propose the new genus Halitrephes.

158 THE MEDUSAE.

Halicreas Fewkes, 1882.

sens. em. Maas, : 05.

Halicreasidae with exumbral warts; with eight radial canals.

The original specimens for which Fewkes (’82°) founded this genus were
so fragmentary that little more than the chief generic character, the exum-
bral warts or papillae, could be distinguished. Fortunately, since these
structures are so far unparalleled among Medusae, the generic identity
of his material is not in doubt; but his description (82°, ’86) and figures are
so incomplete, omitting as they do any reference to tentacles or sensory
clubs, that I prefer to follow Maas (:05) in adopting H. papiilosum as
proposed by Vanhdffen. Vanhéffen’s other species, H. glabrum, and #H.
rotundatum must be transferred to the genus Homoeonema, because they lack
the exumbral papillae.

Halicreas papillosum Vanhéffen.

Halicreas papillosum Vanhoffen, : (2, p. 68, taf. 9, figs. 7, 8, taf. 11, ig. 80; Maas, : 05,
p- 57, taf. 10, fig. 70, taf. 11, fig. 72.

? Halicreas minimum Fewkes, ’82», p. 306; ’86, p. 953, pl. 8.

Plate 3, Fig. 3; Plate 33, Figs. 8, 9; Plate 34, Figs, 1-3, 5, 8, 10, 11.

Station 4621; 1 specimen.
Station 4651; in trawl from 774 fathoms; 1 fragmentary specimen.
Station 4647; in trawl from 2,005 fathoms; 3 specimens; fair condition.
Station 4653; in trawl from 536 fathoms; 1 specimen.
Station 4654; in trawl from 1,036 fathoms; 2 specimens; fragmentary.
Station 4665; 300 fathoms to surface; 1 fragmentary specimen.
Station 4666; in trawl from 2,600 fathoms; 1 large specimen.
Station 4668; 500 fathoms to surface; 3 specimens.
Station 4669; 300 fathoms to surface; 2 small specimens.
Station 4670; in trawl from 3,209 fathoms; 1 specimen; fair condition.
Station 4671; 300 fathoms to surface; 1 specimen, 6 mm. in diameter.
Station 4676; 500 fathoms to surface ; 2 specimens; fair condition.
Station 4685; surface; 1 specimen; the disc only.
Station 4691; 300 fathoms to surface; 3 fragmentary specimens.
Station 4707; 300 fathoms to surface; 1 specimen.
Station 4709; in trawl from 2,035 fathoms; fragments.

Station 4711; 300 fathoms to surface; 2 fragmentary specimens.

HALICREAS PAPILLOSUM. 159

Station 4715; 300 fathoms to surface; 1 fragmentary specimen.

Station 4716; 800 fathoms to surface; 1 good specimen.

Station 4717; 300 fathoms to surface; 1 good, and 1 fair specimen.

Station 4717; in trawl from 2,153 fathoms; 1 fair specimen.

Station 4719; 300 fathoms to surface; fragments.

Station 4721; 300 fathoms to surface; fragments.

Station 4724; in trawl from 1,841 fathoms; fragments.

The numbers of tentacles and otocysts per octant, and the conformation
of the apical projection, in the five best-preserved specimens are shown in
the following table : —

4 Diameter. Otocysts AREAS
Station. nate Tentacles per octant. per octant. | Apical projection.

4676, 300 fms. to surface 24 26, 27, 27, 30 | 4 in one | high, triangular, pointed.
4668, 300 fms. to surface | 24 | me a ae ae aye Bighy Harmacy andrea:
4717, 300 fms. to surface 26 23, 23, 26, 19 | 4 in one | broad, low, rounded.
W654, in trawl, 1,036 fms. 29 | | ey pe 29, 33, | 4, 3, | high, narrow, pointed.
4665, 300 fms. to surface 42 31, 26, 17, 30

|
|

4, 3,3 hardly a trace.

The form of the apical projection varies greatly, all stages being repre-
sented in the collection, from a very tall pyramid to an inconspicuous knob ;
and one specimen shows no trace of any projection. This feature, then, as
Maas has already surmised (: 05, p. 56), is not of specific significance. The
bell is stiff and the gelatinous substance thick, as described by all students
who have examined the species.

The eight peculiar radial gelatinous projections of the exumbrella are
represented in the photographs (Pl. 34, figs. 7 and 3, p. ra). Each prom-
inence bears from five to nine rounded conical projections (Pl. 34, fig. 3);
the whole forming a structure totally unlike anything seen in any other
Medusa. They are much more prominent in large than in small individuals.
The portion of the bell below the level of the prominences is thin and flex-
ible, sharply defined from the stiff gelatinous dise above. When, as is often
the case, the entodermic system is torn away, a very definite sculpture of
the oral surface of the disc, consisting of a ridge along the line of each radial
canal and of a rounded prominence between the bases of every two canals,
is revealed (Vanhiffen, : 02”, p. 69).

Tentacles. —The number of tentacles per octant is variable, as appears
from the preceding table. The largest number observed in any octant was

140 THE MEDUSAE.

thirty-five; the smallest, seventeen. Curiously enough this very small num-
ber was counted in one of the largest specimens, 42 mm. in diameter, whence
it appears that the number of these organs is not closely connected with the
size of the Medusae. Vanhdffen (: 02°) has found from twenty-three to forty-
seven per octant, the latter number in a specimen only 32 mm. in diameter.
According to Maas (:05) a specimen in the “Siboga” collection 44 mm.
in diameter had from seventy to eighty tentacles per octant. The radial
tentacles show a constant difference in size from those between the radial
canals, as already noted by both Vanhéffen and Maas, the former being
about twice as long and as stout as the latter (Pl. 34, fig. 2). In strue-
ture, however, both classes are alike. The tentacles are solid; the en-
dodermie layer composed of chordate cells, the ectoderm layer crowded
with nematocysts. Since in all the large “ Valdivia” specimens the tenta-
cles were broken short off, Vanhéffen failed to observe their most character-
istic feature; this is that each tentacle consists of two portions, —a flexible
proximal region in which the endoderm cells are cubical, and a spine-like
distal part, in which the cells of the core are flat and tile-like. The latter is
so stiff as to be more like a bristle than an ordinary tentacle. These two are
sharply separated (PI. 34, fig. 77). In most cases the ectoderm layer is de-
stroyed ; in the few instances in which it persists it is densely crowded with
nematocysts (PI. 33, fig. 9). It appears from Vanhdffen’s (: 02°) studies that
in this species, as in the genus Homoeonema, tentacles of very young
specimens do not show the separation into two regions characteristic of
adults.

Marginal Clubs. — In large specimens there are three or four of these
structures per octant. They are free clubs (Pl. 33, fig. 8), standing on the
bell margin, consisting of ectodermic sheath and a core composed of chordate
endoderm cells. None of the specimens, all of which are preserved in for-
malin, now contain any otoliths; but from the large size of the distal endo-
derm cells it seems probable that one or two otocysts were present, as Maas
(: 06°) believes to be the case in Homoeonema racovitzae.

The radial canals are extremely broad, the stomach flat and without
any trace of manubrium or definite lip.

Gonads. — Vanhiffen has described these organs in the female as “lang-
elliptischen ” (: 02”, p. 69) and containing about fourteen large eggs. In the
male (PI. 34, fig. 7) they are proximal and more circumscribed than he figures
them (: 02°, taf. 9, fig. 8).

HOMOEONEMA. 141

Color. — All the present specimens are colorless. This is in contrast to
Vanhiffen’s observations, inasmuch as he describes and figures the entire
entodermic system as red, and states that only such specimens as have lost
the entire gastro-vascular structures are colorless. Maas (: 05) likewise
represents them as of a pale reddish tint. This difference, however, is not,
to my mind, of specific significance, but is probably such a local color varia-
tion such as occurs in Nausithoe punctata.

The present captures show that Halicreas papillosum is very widely
distributed throughout the tropical and subtropical waters of all oceans. It is
recorded from the Eastern Tropical Atlantic (“ Valdivia”’), and probably from
the western Atlantic, (Gulf Stream H. minima, Fewkes), from the Indian
Ocean (“Valdivia”), the Malay Archipelago (‘“Siboga’’), and is of very
general occurrence throughout the Eastern Tropical Pacific. Browne (: 08)
has likewise recorded a variety, H. antarcticum, from the Antarctic. It is
certainly an intermediate form, although a single very fragmentary disc
was taken on the surface.

Homoeonema Maas, 1897 (non Vanhoffen),
Haliscera Vanhoffen, 1902.

Halicreasidae without exumbral papillae; gonads either proximal or
occupying the central one third of the radial canals.

Following this definition two species, H. glabrum and H. rotundatum, in-
cluded by Vanhéffen in Haliscera because of the large number of tentacles,
fall into Homoeonema.

Maas (: 06°, p. 9) maintains that a new genus should be established
for these two, distinguished from Homoeonema by the position of the
gonads and by the large number of tentacles; but considering how slight
is our knowledge of the two species, this separation seems to me of
doubtful value.

Specific distinctions between the members of Homoeonema are difficult
to draw, because most of the species are so far known only from Van-
héffen’s brief descriptions and figures. He lays stress on the form of
the gonads as a distinguishing character between //. glabrum, IT. rotundatum,
and H. conica, but in his figures (: 02”, taf. 9) these structures are very similar
in the three species. The position of the gonads, whether proximal or
occupying the central one third of the canals, may well be of specific,
even if it is not of generic, importance, and likewise the number of

142 THE MEDUSAE.

a

tentacles per octant; but this has been counted on so few specimens of
H. glabrum, H. rotundatum, and H. conica that we cannot yet lay much stress
on it. Form of the bell is not of much value, because in the present series of
Haliscera papillosum and of Homoeonema it varies greatly. In short, I am
led to agree with Maas (: 06°) that we may as well unite . glabrum and H.
rotundatum. But whether or not Z. conica is alsoa synonym of H. glabrum is
doubtful. Itappears to be separated from H. racovitzae by the position of the
gonads. The specimens in the present collection, which appear, on account
of size at maturity and number of tentacles, to belong to two species, all
have proximal gonads, as have /H. platygonon, H. alba, and H. racovitzae, — all
of which Maas, from recent studies, believes to be distinct. H. platygonon is
easily recognized by its very small size at maturity (4 mm. in diameter) ;
H. racovitzae, so far as we can judge from Maas’s single specimen, by a char-
acteristic intense purple pigmentation of the entodermic system. WH. alba
is larger (30 mm. in diameter) and colorless. Structurally all three are
extremely close together.

The majority of the present specimens seem best referred to H. alba,
because of the position of the gonads, number of tentacles per octant,
general form, and lack of pigmentation. The second species is probably
identical with H. racovitzae, but since the specimens differ from this species
in pigmentation the identification can be no more than provisional.

Homoeonema alba Vanhoffen.
Haliscera alba Vanhoffen, :02, p. 71, taf. 9, fig, 5.
Plate 3, Figs. 1, 2; Plate 33, Figs. 6, 11; Plate 34, Fig. 9.

Station 4663; 300 fathoms to surface; 1 specimen, 20 mm. in diameter.

Station 4668; 300 fathoms to surface ; 1 specimen, 13 mm. in diameter.

Station 4671; 300 fathoms to surface; 1 specimen, 5.5 mm. in diameter.

Station 4676; 300 fathoms to surface; the specimen photographed,
17 mm. in diameter.

Station 4677; 300 fathoms to surface; 1 specimen, 23 mm. in diameter ;
fragmentary.

Station 4679; 500 fathoms to surface; 1 fair specimen, 22 mm. in
diameter.

Station 4691; 300 fathoms to surface; 2 fragments.

Station 4717; 300 fathoms to surface; 1 specimen, 10.6 mm. in

diameter; gonads already developed.

HOMOEONEMA ALBA. 143

The general form of the bell is shown, in side view, in the photograph
(Pl. 3, fig. 2). The central portion of the gelatinous dise is thick and
rounded, the marginal zone thinner. The specimensare all rather flatter, and
have a shallower bell cavity than in Vanhdffen’s figure (: 02°, taf. 9, fig. 5) ;
but since this figure was taken from a preserved specimen (he had only one
specimen), and since the outline varies in different specimens in the present
collection, it is best not to lay much stress on this difference.

Tentacles. — These show the same differentiation into proximal and distal
regions, as well as the same differentiation in size, as do those of Halicreas
papillosum; the radial ones are much stouter and longer than those be-
tween the canals. Most of the tentacles are broken short off, as is
usual in this family. There are from ten to thirteen tentacles per octant
(Pl. 33, fig. 11), this being about the same number that Vanhdffen (: 02°)
has recorded; and even in the smallest specimen (5.5 mm. in diameter)
there are twelve tentacles in the only octant in which counting was possi-
ble. The number of tentacles is thus only about one half as great as in
Halicreas papillosum. This appears to be a fairly constant difference,
and, since the full number is so early attained, may well be accorded
specific value.

Sense organs. — These (PI. 33, fig. 6) closely resemble the otocysts of Hali-
creas papillosum. 1 have not been able to determine certainly whether or
not they contain otoliths. Browne, who has observed the sense organs in
H. platygonon, merely says that “ they are external, fairly large, and have a
short stalk” (:06, p. 175). The greatest number that I have counted
in any octant is three.

Gastrovascular system. — The stomach is broad and flat (Pl. 3, fig. 7). The
mouth is usually wide open, but in one large specimen, 20 mm. in diameter,
it was tightly closed, and easily separable into proximal and distal (lip)
regions. Maas (: 06°, p. 10) considers the conformation of the gastric cavity
a good distinction between different species of this genus; but inasmuch
as different specimens of /. alba show so much diversity, | doubt whether
this character is of any greater taxonomic importance in this family than
it is in the Aequoridae. The radial canals are broad (Pl. 3, fig. 1), though
narrower than in Haliereas papillosum (PI. 3, fig. 3).

Gonads. — These (Pl. 3, figs. 1, 2) are proximal, though not actually
continuous with the central gastric cavity. They vary in position in differ-
ent specimens, being either closer to or farther from the stomach. It is this

144 THE MEDUSAE.

variation which has led me to unite H. alba with H. conica, which differ in this
respect alone. In form they strongly resemble Maas’s figure (: 06°, pl. 1, figs. 3,
4) of H. racovitzae, being rounded and deep (not flat, as in the Geryonidae).
They are thus very different from the sexual organs of Halicreas. Van-
hoffen (: 02°, taf. 9, fig. 5) figures them for the “ Valdivia” specimen as
proximal, but lanceolate or oval, not circular; he does not state whether
they were flat or globular. They are visible, though very small, even in
the smallest specimen, and in the large ones they are very prominent.
In the specimen represented in the photographs (Pl. 3, figs. 1, 2) each
gonad contains many large eggs.

Color. — The majority of the specimens were entirely colorless in life ; but
in one individual the entire entodermic system was of a very pale orange.
Vanhiffen states that the single “ Valdivia” specimen was colorless.

Homoeonema alba is undoubtedly an intermediate form. Vanhéffen has
recorded it from the southeastern Atlantic (42° 18’ 8.; 14° I’ E.), while
the present collection shows that it is of wide distribution throughout
the Eastern Tropical Pacific. H. platygonon is so far known only from the
north Atlantic (Maas, between Iceland and Greenland; Browne, Norway and
Bay of Biscay), while H. racovitzae is recorded from the Antarctic (Maas,
: 06").

Homoeonema racovitzae Maas.

Homoeonema racovitzae Maas, : 06%, p. 10, pl. 1, figs. 3, 4; pl. 2, fig. 13.

In addition to Homoeonema alba the collection contains two specimens
of a second species of the genus taken at Stations 4667, 300 fathoms to
surface, and 4676, 500 fathoms to surface. In most respects they closely
resemble the /7. racovilzae of Maas; but since they lack the characteristic
pigmentation of the latter, as well as on account of the widely separated
localities of capture, identification with that species is only provisional.

They are much smaller than ZZ. alba, the two specimens, both of which
have well-developed gonads, measuring respectively 7.5 and 10 mm. in
diameter. The most important difference from /. alba is in the very small
number of tentacles per octant, neither specimen having more than six
in any octant. This is precisely the number recorded by Maas (: 06°) for
H. racovitzae, and is a strong reason for believing that the present speci-
mens belong to that species. Specimens of ZZ. alba of the same size already
have about twice as many tentacles (ten to twelve per octant). The struc-

HALITREPHES. 145

ture of the tentacles is that typical of the family, the differentiation into
proximal and distal regions being well marked.

Both of the specimens are entirely colorless; Maas’s specimen, on
the other hand, had the gonads and entire entodermal system heavily
pigmented.

Homoeonema species ?
Plate 34, Figs. 4, 6, 7.

The collection contains a single very small specimen of this genus, taken
at Station 4676, 300 fathoms to surface, too young for specific identification.
A general oral view of this individual is shown in the photograph (PI. 34,
fig. 6). In outline the bell is flat, the gelatinous substance thin. In diam-
eter it measures 7.5 mm., a size at which HZ. alba already has ten to twelve
tentacles per octant. There are very few tentacles, the numbers per
octant being 3, 2, 3, 3, 3, 3, 4, 3. In the octants in which there are three
there is an interradial tentacle flanked on either side by a very rudimentary
adradial one. Structurally the tentacles differ from those of adults of this
genus, in that they do not show any differentiation into two regions, but
are soft and flexible throughout their entire length. There is a single
otocyst, of the typical halicreid form, in each octant (Pl. 34, fig. 4).

The stomach is flat, mouth open, radial canals broad (Pl. 34, fig. 6); two
of the latter unite at their bases.

There is as yet no trace of gonads.

Color. —In life, the entire entodermic system was of a pale orange tint.

Halitrephes, gen. nov.

Halicreasidae with numerous (twenty-eight) radial canals; without ex-
umbral papillae.

This genus is proposed to contain a new species which on account of
the structure of tentacles and otocysts, the breadth of the radial canals,
and conformation of the gastric cavity, undoubtedly belongs to the Hali-
creasidae, but which differs from all other members of the family in having
a large number of radial canals. The general appearance is so much
like that of Aequorea that, until I examined the marginal organs, I be-
lieved that it belonged to that genus. I take pleasure in naming the one
species after Prof. Otto Maas, in recognition of the valuable results of

his studies on this family.
10

146 THE MEDUSAE. ry

Halitrephes maasi, sp. nov.
Plate 33, figs. 1-5, 7, 10; Plate 46, fig. 13.

Station 4646; 300 fathoms to surface; fragmentary, only the disc.

Station 4653; 300 fathoms to surface; fragmentary, only the disc.

Station 4668; bottom of Tanner net; from about 300 fathoms; type
specimen, in fairly good condition.

Unfortunately the type specimen alone is in good condition, the other
two being so fragmentary that their identification is doubtful.

Diameter of the type 55 mm. The exumbrella surface is smooth and
rounded ; the bell low; the gelatinous substance thin and very brittle; the
subumbrella cavity shallow.

Tentacles. —These are of different sizes, though structurally all alike
(Pl. 45, fig. 13). They show the characteristic separation into proximal
and distal portions in less marked degree than other members of the
family. This may, however, be due to the rather soft condition of the
specimen. The distal portion of the tentacles, though thinner and stiffer
than the proximal (Pl. 33, fig. 2), is less spine-like than in Halicreas. The
differentiation of the entodermal core into two regions is sharp. The ecto-
dermic layer of the distal portion, which is rather thick and densely crowded
with nematocysts (Pl. 33, fig. 7), is preserved in many of the tentacles.
When it is partially destroyed the stiff core is revealed. All the ten-
tacles, even the smallest, arise from triangular entodermic roots; those of
the larger ones extending across the circular canal. There are about
seventy tentacles of various sizes; usually one lies opposite each canal.
Many of them are broken short off, as is seen in the general view (PI. 33,
fig. 4).

Otocysts. —These, as in other members of the family, are free clubs,
consisting of an ectodermic sheath and entodermic core. I have not been
able to determine on the specimen (preserved in formalin) whether oto-
liths were present, but the appearance of the sense organs suggests that
they contained one or two such structures (Pl. 33, fig. 10). They are easily
distinguished from small or rudimentary tentacles by their definite form,
uniform size, and by the fact that they lack the entodermic roots character-
istic of the latter. On account of the condition of the margin I was unable
to count the otocysts; but they are certainly much less numerous than the
tentacles (Pl. 45, fig. 13).

LEPTOMEDUSAE. 147

Gastrovascular system. — The central stomach is small, only about 15 mm.
in diameter; the mouth widely open, without any sign of proboscis, and
surrounded by a simple circular thickening. Twenty-eight radial canals
arise from the stomach; five of these then branch dichotomously so that
thirty-three extend to the margin. The canals, both radial and circular, are
very broad (PI. 33, fig. 4).

Gonads. —The gonads are proximal (PI. 33, fig. 4); small, circular, and
flat. Several of the canals appear to lack them, but it is doubtful whether
this is a normal condition. Sexual products are not mature: the speci-
men is apparently a male.

The specimen is entirely colorless, the entodermic system being merely
more opaque than the hyaline disc.

Flalitrephes maasi must be regarded as an intermediate form. It is
one of the few members of this class which has been taken in a closing
net at a known depth. The occurrence of this colorless form at three
hundred fathoms shows the danger of speculating on pigmentation as an

indication of bathymetric range.

LEPTOMEDUSAE.

The genera of Leptomedusae without otocysts have recently been re-
arranged by Maas (:04°) and Browne (:07), who, though differing as to
whether condition of canals or of marginal organs is the more important,
agree that the two families, Cannotidae and Thaumantidae, between which
Haeckel (’79) divided these genera, are purely artificial groupings. In-
deed, one subfamily of the Cannotidae, the Williinae, has been shown by
Browne (:’96) to belong to the Anthomedusae, since the gonads lie on the
walls of the manubrium, not on the radial canals. According to Maas (: 04°)
the remaining Cannotidae are to be divided into two families, Berenicidae
and Polyorchidae, according as they have branched or pinnate canals ; but
Browne (:07) has recently maintained, and I believe correctly, that a
more important character than the condition of the canals is the presence
or absence of the peculiar marginal clubs known as cordyli, their presence
characterizing the family Laodiceidae, which includes most of the genera
grouped by Maas under the heading Berenicidae, as well as several from
the Thaumantidae as defined by Haeckel (’79). The systematist must

recognize the weakness of a classification based upon a single character,

148 THE MEDUSAE.

especially when such grouping runs exactly counter to previous classifica-
tion based upon another single character (in this case the branching of the
radial canals). Nevertheless, I believe that the condition of the marginal
organs is of greater taxonomic value than that of the canals, and that
Browne’s (: 07) revision therefore marks a decided advance over previous
schemes. It must be noted, however,—and this is a point of some im-
portance, — that if we adopt the presence or absence of cordyli as a
character of prime importance, the two resultant groups show parallel
series, each falling into two divisions, the one with simple and the other
with branched canals; while, on the other hand, if we were to retain
the classification based on the condition of the canals, whether branched
or simple, similar parallel series with reference to the presence or absence
of cordyli would result. Those members of the old family Thaumantidae
which remain after the removal of the genera with cordyli stand in need
of further revision.

The genera of Leptomedusae with otocysts show their family relations
much more clearly than do those without such organs, it being now very
generally agreed that they represent two families, Eucopidae and Aequo-
ridae, though the position of one or two genera, whether in one or the
other, has been a subject of discussion. There is little doubt that these
two families are much more intimately related to each other than is either
of them to any of those members of the order which lack otocysts.

No representatives of the genera with neither cordyli nor otocysts, nor
of those with branched canals, are contained in the collection; and there
is only one genus of Laodiceidae, Ptychogena. Eucopidae and Aequoridae,
on the other hand, are well represented.

Laodiceidae L. Agassiz, 1862.

sens. em. Browne (: 07).

Leptomedusae without otocysts, but with cordyli on the margin of the
bell.

For generic definitions of the members of this family we may well
follow Browne (:07), especially since his revision, though resulting in the
suppression of several species, has not necessitated a general transfer of the
well-known members of the family. According to Browne six genera of
Laodiceidae are recognizable :— Laodice, with four radial canals, central

PTYCHOGENA. 149

mouth, and ocelli on the basal bulbs of the tentacles ; Staurophora, differ-
ing from Laodice by the peculiar and extensive development of the mouth;
Ptychogena, resembling Laodice except in lacking ocelli; Saurodiscus, in
which each of the four radial canals has two lateral branches; Toxorchis,
with six branched radial canals; and Melicertissa with eight unbranched
canals. The present collection contains examples of one only of these
genera, Ptychogena.

Ptychogena A. Agassiz, 1865.
sens. em. Browne (: 07).

Laodiceidae with four unbranched radial canals; with central mouth and
stomach ; without ocelli on the basal bulbs of any of the tentacles,

According to Browne’s revision of this genus three species can be recog-
nized : — P. lactea A. Agassiz ('65), P. longigona Maas (93), and P. antarctica
Browne (:02), of which only a preliminary account has yet appeared. P.
pinnulata Haeckel (’79, 81) appears to be indistinguishable from P. /actea,
since the slight differences in the form of the gonads supposed by Haeckel
to separate the two species represent nothing more than different stages
in development. Indeed an intermediate step between the two has been
described by Linko (: 00). As Browne says (:07, p. 473), P. dactea is prob-
ably an arctic species, and there is no evidence that it belongs to the inter-
mediate fauna. P. longigona is distinguishable from P. ductea by the length
of the gonads, which extend along the entire course of the radial canals,
and by the fact that there are no distinct lateral diverticula on the radial
canals, although the gonads are arranged in folds. Unfortunately the margin
has not been figured, so that I can say nothing as to the form of the basal
bulbs of the tentacles, a feature which appears to be of some systemic sig-
nificance in this genus. In P. antarctica, founded for a single fragmentary
specimen, the radial canals have wavy margins corresponding to the principal
folds of the gonads; but no true diverticula such as are seen in P. /actea
(Browne, :07, p. 474), and the red color of the tentacles of P. antarctica
further serves to separate the two; the tentacular bases, however, like those
of P. lactea, are laterally compressed. From P. dongigona it is apparently
distinguishable by the shortness of the gonads; but Browne (: 07) states
that, owing to the brevity of Maas’s description of the latter, the relation-
ship of the two is doubtful. For a final decision on this point we must

await the full description and figures of P. antarclica.

150 THE MEDUSAE.

The series in the present collection is certainly very distinct from
P. lactea, but closely related to P. dongigona and P. antarctic. From the former,
however, it can be distinguished by the much smaller number of tentacles,

and from the latter by the shape of the tentacular bulbs.

Ptychogena erythrogonon, sp. nov.
Plate 5, Fig. 1; Plate 38, Figs 8, 9; Plate 39, Figs. 1-7.

Station 4646 ; 300 fathoms to surface ; 1 good specimen.

Station 4650; 300 fathoms to surface; 1 small specimen, fair condition.

Station 4653 ; trawl from 336 fathoms; 3 specimens, somewhat battered.

Station 4654; trawl from 1,036 fathoms; 3 fragmentary specimens.

Station 4655; 300 fathoms to surface; 1 large specimen, good condition.

Station 4661; 300 fathoms to surface; 1 immature specimen, excellent
condition.

Station 4666; trawl from 2,600 fathoms; 1 specimen, fragmentary.

Station 4671; 300 fathoms to surface; 1 good specimen. Type.

Station 4675; 300 fathoms to surface; 1 fair specimen.

The series is particularly interesting in containing several successive stages
in the development of the gonads. Several of the specimens are in excellent
condition, and even the fragmentary ones allow most of the details of struc-
ture to be made out.

The form of the bell is characteristic, its gelatinous substance being so
thick, and the umbrella cavity so shallow, that the Medusa is almost globular
(P1. 39, fig. 7). This character is probably of specific significance, for it is very
constant in the series (both in the fresh condition and after preservation),
while the three other members of the genus are of more moderate outline.
The largest specimen is 38 mm. in diameter by about 25 mm. high.

Tentacles. — The number of tentacles is much smaller than in either P.
lactea or P. longigona. In the only specimen in which the entire margin was
preserved, 50 mm. in diameter, Station 4671 in the above table, there were
forty-three ; the numbers in each quadrant, counting the tentacles opposite
the canals, being twelve, ten, ten, and eleven. In larger specimens the num-
ber is greater, the largest number counted in a single quadrant being sixteen,
in a specimen 36 mm. in diameter. In the smallest individual, 18 mm. in
diameter, there are about twenty-four tentacles in all; and in one slightly
larger (24 mm.), but still without any trace of gonads, about twenty-two. In

PTYCHOGENA ERYTHROGONON. ily

addition to the well-developed tentacles several specimens have one or two
small ones, evidently in process of development (PI. 39, fig. 5). The ten-
tacles are very short and stout; their conical basal bulbs (Pl. 39, fig. 5) are
not laterally compressed as they are in P. dactea and P. antarctica, but more
nearly resemble in outline the corresponding structures as they are described
in the various species of Laodice. This difference in the form of the basal
bulbs in different species of the genus is probably correlated with difference
in the number of tentacles; the bulbs are laterally compressed in species
in which the tentacles are crowded, and conical when these organs are
widely spaced.

Cirri. — In addition to the tentacles there are a small number of solid cirri
(Pl. 39, fig. 5), which bear nematocyst clusters at their tips (PI. 38, fig. 9).
In none of the specimens did I find more than three of these structures ;
several had only one or two, and others had none at all.

Cordyli. — These organs (Pl. 39, fig. 5, co; Pl. 38, fig. 8) are of the struc-
ture so well described by Brooks (’95) for Laodice. They contain no oto-
lithic concretions of any kind. As a rule there is one cordylus between
every two tentacles; but occasionally there are two, so that in every indi-
vidual in which they were counted the number of cordyli slightly exceeds
that of tentacles (Pl. 39, fig. 5). It is evident, then, that the question whether
there are one or two between every two tentacles is of no greater systematic
importance in Ptychogena than Browne (: 07) considers it in Laodice.

Manubrium. — The manubrium is quadrate basally ; in young specimens it
is very large (Pl. 39, fig. 6), but its growth does not keep pace with that of
the bell, so that in adults it is proportionately much smaller. It is barrel-
shaped in outline, and the mouth is surrounded by a simple circular thicken-
ing, widely open in all the specimens (PI. 39, fig. 7). In oral view it much
resembles the figure given by Maas (’93, taf. 6, fig. 7) for P. longigona, as
well as for Laodice jijiana (Maas, : 05, taf. 5, fig. 34).

Radial canals and gonads. —In the smallest specimen the radial canals,
though broad, are simple in outline, without diverticula or even waviness
(Pl. 39, fig. 6); but in the specimen 24 mm. in diameter they have developed
a series of short lateral diverticula along the narrow lines by which they
are attached to the subumbrella (Pl. 39, fig. 2). The main bodies of the
canals, however, are so stout that they extend out as far as the ends of these
short branches. The gonads develop in the spaces between the diverticula,

and are confined to the aboral surfaces of the canals, close to the subumbrella,

152 THE MEDUSAE.

as is seen in side view (PI. 39, fig. 4). As the genital folds grow larger and
larger they gradually obscure the diverticula of the canals (PI. 39, fig. 3)
until finally it appears as though the latter were merely wavy in outline,
as Browne (: 02) has described them for P. antarctica. This structure of the
canals and gonads is similar to that found in P. longigona by Maas, who
states that the canals “ sind an und fiir sich einfach und zeigen Ausbuchtungen
nicht selbstiindig, sondern nur in Zusammenhang mit Gonaden entwickelt ”
(93, p. 66). The gonads extend for nearly the entire length of the canals,
but do not quite reach their distal extremities. ,

Color.— The color of this species is one of its most striking characters.
The basal parts of radial canals and manubrium as well as the tentacular bulbs
are of a very brilliant opaque brick-red ; while gonads, distal portions of the
canal system, and extremities of the tentacles are of a paler shade of the
same color, Along the central line of each radial canal is a pale band,
these four bands forming a cross on the base of the stomach (Pl. 39, fig. 7).
The pigmentation is both ectodermic and endodermic, The endoderm cells
contain masses of red, yellow, and black pigment spherules of large size,
while the ectoderm cells in the pigmented regions are crowded with
minute red granules.

Ptychogena erythrogonon is evidently an intermediate form. So far as
the present collection illustrates its range, it appears to be confined to the
Humboldt Current, in the neighborhood of the Peruvian coast. Of the three
other members of the genus, one, P. antartica, is from the Antarctic ; two,
P. lactea and P. longigona, from the north Atlantic. P. lactea is probably a
surface form; P. longigona is almost certainly from the intermediate waters,
while we have as yet no data as to the bathymetric occurrence of P. antarctica.

Eucopidae Gegenbaur, 1856.

Leptomedusae with closed otocysts; with four, six, or eight radial
canals; with gonads lying alone the canals; with well-developed barrel-
shaped manubrium.

Only one of the four subfamilies of Eucopidae proposed by Haeckel,
(79) the Eutiminae (Maas,: 05), has stood the test of time. This sub-
family, including forms with a long peduncle and with only eight oto-
cysts, seems sufficiently well characterized. The other subfamily with a

peduncle, Kireninae (Haeckel), with more than eight otocysts, must be

PHIALIUM. 153

abandoned, for the peduncle is a feature which is variable, and may even
be present to a slight degree in adults of such genera as Phialidium and
Phialucium, so that among the species with numerous otocysts there is no
break in the series from forms without peduncle to others in which this organ
is well developed. The interrelationships of these genera are so puzzling
that no altogether satisfactory subdivision of them has yet been devised.

Maas (:05) has recently transferred the subfamily Octocanninae, with
eight radial canals, from the Aequoridae to the Eucopidae, and on sufti-
ciently good grounds.

Phialium Haeckel, 1879.

Eucopidae, with twelve otocysts, and four chief radial tentacles flanked at
their swollen bases by lateral cirri; with or without additional tentacular
bulbs on the margin; without peduncle.

This genus was instituted by Haeckel (’79) to contain the Eucheilota
duodecimalis of A. Agassiz (65), which, as A. Agassiz had pointed out, differs
from the Lucheilota ventricularis of McCrady ('57) in having twelve instead of
eight otocysts, and which A, Agassiz thought would be found, when better
known, to belong to another genus. Haeckel added a second species, P. dode-
casema, from one of Agassiz’s figures, believing that the latter had observed
two distinct species; but Fewkes (’82”) has shown that the two supposed
forms represent merely two contraction phases of the one species. The
genus has been accepted by Fewkes (’82°), but so far as I can learn it
has not appeared elsewhere in literature, both Mayer (: 00°) and Hargitt
. (:05>) having used the name Eucheilota in a broad sense to include both
species with eight and those with twelve otocysts. It is best to retain
Haeckel’s genus, as distinguished from Eucheilota, inasmuch as it is
separated from the numerous species with eight otocysts (Hucheilota), not
only by the number of these organs, but also by the limited number of de-
veloped tentacles (four radial) and by the extreme development of the
gonads.

I have been able to find no other species which can certainly be referred
to this genus, although it is possible that Mitrocomium assimile Browne (: 05°),
from Ceylon, may belong here. The present collection contains a consider-
able series of specimens indistinguishable from Phialium duodecimalis trom the
Atlantic coast of the United States.

154 THE MEDUSAE.

Phialium duodecimalis A. Agassiz.

Eucheilota duodecimalis A. Agassiz, "62, p. 353; 65, p. 75, figs. 106, 107, 107a ; Hargitt,
: 05°, p. 46, pl. 4, fig. 3.

Phialium duodecimale Haeckel, ’79, p. 180; Fewkes, ’82°, p. 297, pl. 1, figs. 17-21.

Phialium dodecasema Haeckel, ’79, p. 181.

Plate 6, Fig. 4; Plate 38, Figs. 4, 5.

Acapulco Harbor; surface; many specimens, | to 2 mm. in diameter.

It has been my good fortune to have access to a large series of P.
duodecimalis, from Newport, R. I., for comparison with the present speci-
mens, and, as in the case of Phialidium discoida, I have been unable to find
that there are any constant differences to separate the two. The Pacific
series, none of which are full grown, agree closely in general form, and in
the size and shape of the gonads, with Atlantic specimens of about the
same size.

The most important specific characters are to be looked for on the
marginal organs. In each specimen there are four radial tentacles, with
swollen conical basal bulbs flanked with from one to four pairs of cirri; and
twelve otocysts, three per quadrant, each containing a single large otolith ex-
actly as is figured for P. duodecimalis by A. Agassiz (65, fig. 107) and by Fewkes
(82°, figs. 77-21). There are no rudimentary tentacular swellings on the
margin in any of the specimens. Such structures, alternating with the oto-
cysts, have, it is true, been recorded, but not figured, by Fewkes (’82°) for
very large specimens from Newport; but inasmuch as Hargitt (: 05°) has not
observed any, but states expressly that there are only four tentacles, and
since the writer has never seen any in the numerous large specimens from
the Atlantic coast of the United States which he has examined, it is probable
that the specimens with more than four developed tentacles, which Fewkes
records, in reality belonged to Hucheilota ventricularis, a species which might
sasily be confused with the present if the otocysts were not counted.

In all the specimens gonads were developed, but in none were they of
such large size as they finally become. In some of the Newport specimens
they are so swollen that they fill almost the entire bell.

The Medusae are entirely colorless.

So far as I have been able to learn, the only species known from the
Indo-Pacific region which resembles this species is the Mitrocomium assimile

described by Browne (: 05°, p. 137, pl. 1, fig. 8) from Ceylon. Unfortunately

PHIALIDIUM DISCOIDA. 155

his single specimen was in such poor condition that he was unable to count
the otocysts with any certainty, being able to find only five, so that positive
generic identification was impossible. From its general form, and from the
form and extent of the gonads, I think it probable that it is either a Phialium
or a Eucheilota, not a Mitrocomium ; but it differs from the present series
in having a large interradial bulb and from four to six small adradial bulbs
in each quadrant in addition to the four primary radial tentacles. Fewkes’s
(’82°) account would suggest, as noted above, that this distinction was of
doubtful value, but from my own studies I conclude that it is probably quite
as significant in this genus as it is in Phialidium,

Phialidium Leuckart, 1856.
Haeckel, 1879.

Eucopidae with numerous otocysts, one or two between every two of the
numerous tentacles; without marginal cirri or papillae; no well-developed
peduncle.

This genus has commonly been called Oceania by American authors, but
the name Phialidium is preferable in the interests of stable nomenclature,
because identification of the species to which Oceania was originally applied
is very doubtful; while Oceania has been employed in widely different
senses by later authors (e. g. for Anthomedusae Vanhoffen, ’89).

The Atlantic species referable to this genus are so puzzling in their
synonomy, owing to their great variability, that they have long been a thorn
in the side of the student of Leptomedusae. The following species have been
described from the Pacific : —P. gregaria A. Agassiz; P. pucifica Agassiz and
Mayer; P. ambiqua Agassiz and Mayer ; and P. brunescens Bigelow. Another
Pacific species of Oceania, P. virens Bigelow (: 04), has since been made the
type of the new genus Phialucium by Maas (: 05).

The present collection contains one species of the genus indistinguish-
able, on comparison with actual specimens, from the West Indian P. discoda
of Mayer.

Phialidium discoida Mayer.
Oceania discoida Mayer, : 00", p. 51, pl. 20, figs. 53-55.

Plate 6, Fig. 8; Plate 38, Figs. 6, 7.

Acapulco Harbor; surface ; many specimens, | to 3.5 mm. in diameter.
The resemblance between these specimens and a collection of P. discoida

156 THE MEDUSAE.

from the West Indies is so close that I have been unable to find a single
feature to separate them.

The largest specimen measures 3.5 mm. in diameter ; but inasmuch as
this individual has several tentacles only partly developed, it is evident that
this is not the extreme size, but that Pacific like Atlantic specimens grow
much larger. The largest West Indian specimen is 5.5 mm. in diameter.
This is larger than any recorded by Mayer; and the fact that the specimens
which he described were immature no doubt explains the few discrepancies
between his account and the West Indian specimens which I have studied.

The bell is flat; seldom circular, but usually irregularly rectangular in
outline, from muscular contraction ; its cavity very shallow.

Tentacles. —The largest number counted, in a specimen 2.5 mm. in
diameter, was thirty-nine, of which one was rudimentary. The smallest
number was twenty-four, one rudimentary ; the majority of specimens, 2 to
2.5 mm. in diameter, have from thirty to thirty-six tentacles, with from one
to four rudimentary. In a larger specimen from the West Indies, 3.5 mm.
in diameter, there are forty-six tentacles, and in another, of 3 mm., forty.
The tentacular bases form swollen, almost spherical bulbs, very sharply
separated from the slender distal portion of the tentacle, a characteristic
feature which is one excellent mark of the species (Pl. 38, fig. 6). In con-
tracted specimens these bulbs are usually in close contact with one another ;
and even when the bell is expanded, though they are then separated by
considerable spaces, they are more crowded than in any other species of the
genus which I have studied. A similar form of the tentacles in Maas’s (: 06°,
pl. 2, fig. 7) figure suggests that his P. pacifica, from Amboina, is really not
the Oceania pacifiea of Agassiz and Mayer (’99), but is more nearly related
to P. discoida, if not identical with it.

Otocysts. —In both Pacific and West Indian specimens there is usually
only a single otocyst between every two tentacles. Mayer (: 00°), however,
has recorded from one to three otocysts between every pair of tentacles ;
but this diserepancy of observation is probably due to the fact that all of his
specimens were immature and that the final number of tentacles had not yet
developed. ‘The number of otoliths in each otocyst varies from one to four;
possibly even more. Counting the otocysts is somewhat uncertain, because
of the crowded condition of the basal bulbs of the tentacles; and perhaps
in some cases there may be more otocysts than I have been able to find.

(Gonads. —The large size of the gonads is a specific character of as much

PHIALUCIUM. 157

importance as is the form of the tentacular bulbs. They usually occupy
the distal two thirds of the canals, but occasionally extend the entire length
of a canal. Such a variation is to be seen on the different gonads of the
specimen photographed (PI. 6, fig. 8). Gonads are present, though of small
size, even in specimens only 1.5 mm. in diameter. In females the ova are
very large. The collection contains both, males and females.

The manubrium is short, and quadrate in outline; the mouth surrounded
by four simple lips.

Color. — The Medusae were entirely colorless in life.

The difference in number of tentacles and of otocysts between the present
specimens and Mayer's (: 00°) account of P. discoida might perhaps have
seemed of specific importance had I not had access to a West Indian series,
from near the type locality. Iam now convinced that these differences are
due to different stages in growth, a conclusion in no way negatived by the
large size (4 mm.) of Mayer’s specimens, since his description was written
from fresh specimens, while the measurements in the present account were
taken from preserved material; but whether or not my identification of
this series with the form described by Mayer is correct, the significant
fact of the identity of the Pacific with a West Indian form remains.

Phialucium Maas, 1905.

sens. em.

Eucopidae with numerous tentacles and otocysts (number indetermi-
nate) ; with rudimentary as well as large tentacles; with or without cirri.
Rudimentary tentacles may be developed at a late stage in growth.

Phialucium was proposed by Maas (: 05) as a subgenus; but it is worthy
of full generic rank.

As defined by Maas it lacks cirri; but a species in the present collection
which has cirri flanking the tentacles, in other respects so closely resembles
the type species, P. virens Bigelow (:04), that it is best to discard the
presence or absence of these organs as a generic character. The genus
may be regarded as intermediate between Phialidium and Kirene, since
West Indian specimens, to be described below, acquire a rudimentary
peduncle when fully grown, but only long after the appearance of the
gonads. Up to the present time two species only have been described
which are referable to this genus, Oceania vwirens Bigelow (: 04)

158 THE MEDUSAE.

(Phialidium tenue Browne, :04) and Oceania carolinae Mayer (: 00°). These
two are clearly separable by the number of marginal organs; for though
the number of tentacles and tentacular bulbs is variable, they are con-
siderably more numerous in P. virens than in P. carolinae, while the number
of otocysts in the former is only about one half as great as it is in the
latter. P. carolinae has been recorded but once, from Charleston, 8. C.;
while P. virens is now known to be widely distributed over the Indian
Ocean and Malaysian region (Bigelow, : 04, Browne, :04, Maas, : 05, : 06°),
and it is perhaps the same species as Mitrocoma mbengha which was
described by Agassiz and Mayer (’99) from the Fiji Islands. The present
collection contains a series referable to this same genus, but differing in an
important character, 7. e. presence of cirri, from both P. virens and P.
carolinae. This species is, however, closely allied to, if not identical with,
certain specimens from the Island of Guadaloupe, West Indies, in the
collection of the Museum of Comparative Zodlogy, and is apparently
undescribed.

Phialucium comata, sp. nov.
Plate 5, Figs. 6, 7; Plate 6, Fig. 9; Plate 37, Figs. 9, 10, 12.

Acapulco Harbor; surface; 5 specimens, 3 mm, to 6 mm. in diameter.
Type 6 mm. in diameter (also Guadeloupe Island, West Indies; surface ;
9 specimens, 3.5-12 mm. in diameter).

In general outline the bell is high (PI. 5, fig. 7), the gelatinous substance
thick, and the umbrella cavity deep. In none of the Pacific specimens is
there any trace of peduncle or even any swelling of the gelatinous sub-
stance at the point where the manubrium is situated. The same is true
of the West Indian specimens from 3 mm. to about 9 mm. in diameter ;
but in the largest, 12 mm. in diameter, the manubrium is situated on
a broad but very low swelling. This, however, is not sufficiently pro-
nounced to warrant referring the species, on the ground of its possessing
a distinct peduncle, to Kirene.

The only difference between the Pacifie and the West Indian specimens
is afforded by the number of tentacles and tentacular knobs. In the
largest specimen from Acapulco there are seventeen tentacles and twenty-
three knobs; in the smallest, eight tentacles and eight knobs; but in
specimens of corresponding sizes (6 mm. and 3 mm.) and stages of develop-

ment from the Atlantic the number of knobs is considerably greater, there

PHIALUCIUM COMATA. 159

being from thirty-nine to fifty and from twenty to twenty-two respectively.
This divergence seems to indicate the existence of two distinct varieties of
the species. The number of tentacles, although variable, is about the same
in both collections. In specimens 12 mm. in diameter the knobs have
largely increased in number, there being as many as sixty-two; but the
largest number of tentacles observed was nineteen. It appears, then, that
no great further increase in tentacles is to be looked for; and therefore
it is almost certain that the great majority of knobs in this species, as in
P. virens and P. carolinae, never develop into tentacles. The tentacles are
short, with swollen basal bulbs, and are flanked with from one to three
pairs of lateral cirri (Pl. 37, fig. 10). The same is likewise true of the
larger knobs. The small knobs, however, have no cirri.

Otocysts. —The sense organs are so large and prominent (PI. 37, fig. 9),
that I suspected at first that they might be open; but a study of sections
has demonstrated that they are merely closed vesicles of large size. It is
impossible to tell the normal number of otoliths on preserved specimens.
The number of otocysts is variable, but apparently always small, and not
subject to increase with the later growth of the medusa. In the two
largest Pacific specimens, 5 mm, and 6 mm. in diameter, there are fourteen
and nine respectively. In West Indian specimens the numbers counted
are: —3.5 mm., seven otocysts; 7 mm., eleven otocysts; 12 mm., nine
otocysts; 12 mm., ten otocysts. They are irregularly arranged, in several
eases three in one quadrant, with only one in the adjoining quadrant,
while in one individual one quadrant altogether lacked otocysts.

The manubrium is short, and flask-shaped; the mouth is surrounded
by four slightly crenulated lips.

Gonads. — The gonads first appear as small globular swellings at the
middle points of the radial canals, and with the growth of the medusa
they grow distally. In the largest Pacific individual they occupy the
central one third of the canals; and in the still larger West Indian
specimens they extend out nearly to the extremities of the canals. They
remain linear, however, increasing but slightly in thickness, while even in
small specimens large ova are to be seen, Their general appearance,
therefore, apart from size, gives no clue to the stage of development of
the specimen. The collection contains both males and females.

Color.—In life the gonads in both collections were slightly greenish,

but the specimens otherwise were colorless.

\

160 THE MEDUSAE.

The difference between the two series of specimens, Pacific and West
Indian, consisting merely of a slight divergence in such a variable character
as the number of rudimentary tentacular knobs, seems to me too slight to
warrant separating them specifically. To determine whether it even indi-
cates the existence of two distinct geographic races of the one species
requires an examination of additional large specimens, particularly from the
Pacific.

P. comata is clearly distinguished from the other members of the genus
by the presence of lateral cirri at the bases of the tentacles, a very
constant and reliable character; and by the small number of otocysts.
In the large size of the latter, however, it resembles P. virens.

Eirene Eschscholtz, 1829.
Haeckel, 1879.

Eucopidae with well-developed gelatinous peduncle; with numerous
otocysts and tentacles; gonads restricted to the subumbrella.

Haeckel (’79) enumerated only four species of this genus : L. pellucida Will,
E. viridula Lamark, E. gibbosa McCrady, and £. coerulea L. Agassiz. To these
must be added the Eutima pyramidalis of L. Agassiz, which has since been
redescribed by Mayer (:00°) under the name Phortis pyramidalis. All these
are Atlantic forms. Since Haeckel wrote, five new species have been
described :— F’. lactea Mayer (: 00°), from the West Indies, £. kambara Agassiz
and Mayer (99), from the Fiji Islands, and £ danduensis Bigelow
(:04), 2. ceylonensis Browne (:05°), and #. palkensis Browne (:05°), from
the Indian Ocean. It is, however, doubtful whether all of these are truly
distinct; indeed the status even of the two longest known species, H. pel-
lucida and E. viridula, is not yet satisfactorily determined. The probability
is that they are specifically identical, but as Mediterranean and Atlantic
specimens are known to have a wide range of variation in size, tentacle
number, and form of the peduncle (Haeckel, 79; Maas, ’93), it is possible
that the 2. viridula—F. pellucida group may in reality comprise two or
more geographic races. This species, or group, is apparently the most
widely distributed of the genus; but though it has been recorded twice
from the Indian Ocean (Chun, °96; Goette, 786), there seems to be no
record of its occurrence on the western side of the Atlantic. . danduensis
and 2. palkensis show many features in common; in both there are com-

paratively few tentacles, with a large number of rudimentary tentacular

EIRENE MEDUSIFERA. 161

knobs; in both the peduncle is long and in both the gonads are linear.
The only important differences between the two are the facts that 2. pal-
kensis has a much shorter manubrium than £. danduensis, and that Browne
was unable to find any lateral cirri at the bases of the tentacles in the
former, while I have recorded such structures for the latter; but neither of
these differences is as important as it might seem at the outset, for the first
character is subject to great variation owing to contraction; the absence
of cirri in #. palkensis may perhaps be explained by the fact that the
bell margins of all the specimens were much damaged (Browne, : 05°). I
therefore believe that in all probability the two are identical.

Browne was no doubt justified in separating LL. ceylonensis from L.
palkensis (danduensis) in spite of the close general resemblance between
the two, on the grounds that the former has a very much larger number
of tentacles (100), but neither cirri nor tentacular knobs, It appears to
represent a good species. Both of these Indo-Pacific species (or three if
£. palkensis be recognized as separated from L. danduensis) are sufficiently
well distinguished by anatomical characters from any of the Atlantic mem-
bers of the genus. The status of LZ. kambara Agassiz and Mayer is less
easily settled. From their figure ('99, pl. 8, fig. 29) it is evident that the
specimen was immature; although they mention gonads, the figure shows
none; and the fact that the margin bears neither cirri nor knobs suggests
that it may be the young of £. cey/onensis. If this is the case, however, the
peduncle must grow very considerably in length during the later stages
of development, for it is figured by them as very short in £. kambara.

The present collection contains two species referable to Eirene; one,
represented by only a single specimen, from the open ocean, is indistin-
guishable from Z. viridula. The other represented by a considerable

series, is apparently new.

Eirene medusifera, sp. nov.
Plate 37, Figs. 1-8.

Acapulco Harbor; surface ; 23 specimens, 2.5-8 mm, in diameter. Type
7 mm. in diameter.

The specimens are all in excellent condition.

The bell is of moderate height, the jelly rather thin. The peduncle

(Pl. 37, fig. 6) is conical, and hangs about to the opening of the bell.
ll

162 THE MEDUSAE.

The manubrium is short and nearly spherical, the mouth surrounded by four
simple lips.

Tentacles. — The largest number of tentacles observed was twenty-one, in
a specimen 8 mm. in diameter. In small specimens 2-4 mm. in diameter
there are from eleven to fifteen tentacles. Besides the developed tentacles
all the specimens, even the largest, have tentacles in process of formation,
which vary from small rudimentary swellings to fully formed tentacles of smal!
size. In small specimens the rudimentary knobs are about as numerous as
the tentacles (Pl. 37, fig. 7); but in large specimens they are fewer, one
specimen with seventeen large tentacles having only ten knobs, several of
which already clearly show that they are young tentacles. Since the knobs
show all stages in growth, it seems that none of them permanently retain
the rudimentary character seen in the knobs of #7. danduensis and E. viridula,
but that probably the adult specimens have fully formed tentacles only.

All the tentacles, whether fully formed or rudimentary, are flanked at
their bases by a pair (sometimes two pairs) of lateral cirri (Pl. 37, fig. 2),
but there are no cirri scattered along the bell margin such as are character-
istic of L. viridula. The tentacles have swollen, conical bases, and very deli-
cate, thread-like extremities. When fully expanded they are about as long
as the radius of the bell, but in the preserved specimens most of them are
contracted.

Otocysts. — The otocysts are about as numerous as the tentacles (large
and rudimentary), and alternate with them. In the early stages in the
growth of a new tentacle the new rudiment is formed between the otocyst
and one of the tentacles flanking it, and a second otocyst is developed
later. Thus, succession is of course a further argument in favor of the view
that all the knobs in this species represent merely the early stages of devel-
oping tentacles. The largest number of otocysts observed was twenty-seven
in the specimen above mentioned which had twenty-one large tentacles and
eight rudimentary ones. The sense organs, which are of small size, each
contain from two to five or more spherical otoliths.

Hirene medusifera is the second known case of a Leptomedusa giving rise
to free medusa buds, the first being afforded by Eucheilota parodoxica (Mayer,
: 00°, : 04), and in it, as in this latter species, the buds are developed from the
region of the gonads. These organs occupy the distal third of the radial
canals (not, however, extending quite to the bell margin); and are cylindri-

cal in form. A photograph of a gonad with several growing buds is repre-

EIRENE VIRIDULA. 163

sented in Pl. 37, fig. 8. Seventeen out of the twenty-three specimens show
various stages in budding. The process takes place in the usual fashion,
both germ layers being concerned in the formation of the buds. When set
free, the young medusa has a well-developed manubrium (PI. 37, fig. 7) but
no peduncle, and four primary tentacles with stout basal bulbs. Even at
this early stage the tentacles are flanked by lateral cirri.

Color. — The gonads and manubrium are of a pale yellowish tint; other-
wise this species is colorless.

Kirene medusifera is separated from all other species of this genus by the
structure of the marginal organs. The method of reproduction by budding
which it exhibits likewise distinguishes it from all its near relatives. In the
latter respect it is one of the most interesting medusan finds of the

Expedition.

Eirene viridula Eschscholtz.

For synonymy of this species, see Haeckel, ’79, pp. 201, 202.
Plate 36, Figs. 1-4.

Station 4708; surface; 1 specimen, 15 mm. in diameter.

Fortunately the single specimen was in good condition. The bell is
rather low, only about 3-4 mm. high; the jelly thin. The peduncle is short,
hanging only about to the bell opening, but very broad basally (Pl. 36,
fic. 1). The manubrium is extremely short, indeed rudimentary ; the mouth
is surrounded by four slightly crenulated lips.

Bell margin. —In addition to otocysts, the margin bears tentacles, ten-
tacular knobs, and cirri (Pl. 36, fig. 4). There are twenty-two developed
tentacles, which have stout conical basal bulbs, and are very short,
perhaps the result of contraction. The tentacular knobs are triangular,
of about the same shape as the basal bulbs of the tentacles, and about three
times as numerous as the tentacles. Having only a single specimen, I am
unable to determine whether they represent, in their present state, the
final stage in their development, or whether some or all of them are merely
tentacles in early stages in growth; but as I have found no intermediate
stages, and since the specimen is sexually mature, it is probable that the
first surmise is the correct one. The cirri (Pl. 36, figs. 2, 4) are irregularly
scattered along the margin, and are about as numerous as the tentacles,

There are no cirri flanking the tentacles.

164 THE MEDUSAE.

Otocysts. —There are about thirty-five otocysts (on part of the margin
they are destroyed so that accurate counting is impossible), each containing
from three to five otoliths (Pl. 36, fig. 2).

Gonads. — These are linear and occupy the entire length of the canals
from their distal extremities to the base of the broad peduncle. There are
no sexual organs on the peduncle. The specimen is a male.

Color. — The gonads and manubrium in life were opaque and milky ;
otherwise the Medusa was colorless.

Fxrene viridula is to be distinguished from the other Indo-Pacific members
of the genus by the presence of cirri scattered along the bell margin ; for, al-
though both £. danduensis ( palkensis) and EF. ceylonensis have cirri, they occur
only at the sides of the tentacular bulbs. The present specimen differs from
most descriptions of the Atlantic form in having a very broad peduncle and
few tentacles. It is possible therefore that it may represent a distinct Pacific
race ; but since Maas (93) has shown that the form of the peduncle is vari-
able in /. viriduda, and since the number of tentacles increases with growth,
it is best not to lay stress on these apparent differences until a larger series is
studied. The occurrence of this species in the Pacific is not surprising in
‘connection with the fact that it has twice been recorded from the Indian
Ocean (Chun, 96; Goette, ’86).

Eutiminae Maas, 1905.
Eutimidae Haeckel (’79).

Eucopidae with only eight octocysts; with long gelatinous peduncle.

Modern researches indicate that Haeckel’s genera Eutimium and Kuti-
meta represent merely temporary stages (in the condition of the marginal
organs) of Eutima. Octorchis, Octorchandra, and Octorchidium, in which
sexual products are developed on the peduncle as well as on the subum-
brella, certainly represent only a single genus Octorchis. And this one is
of questionable validity ; for although it is retained by Browne (: 05°), it
seems to me that the discovery by Maas (:05) that some individuals of
Eutima levuka Agassiz and Mayer have gonads both on the subumbrella and
on the peduncle, while others have them only on the subumbrella, throws
doubt on its claim to recognition. Respecting Eutimalphes I cannot agree
with Maas (: 05) that it is closely allied to Tima; for it has the number of
otocysts characteristic of Eutima, from which genus it is separable only by

the somewhat shorter peduncle and the much greater number of tentacles,

EUTIMA LEVUKA. 165

Eutima McCrady, 1857.

Sensu Maas (: 05).

Eucopidae with long peduncle; with only eight otocysts; with only a
small number of tentacles (four, eight, or twelve); gonads on subumbrella,
on peduncle, or on both.

Eutima levuka Agassiz and Mayer.

Eutimeta levuka Agassiz and Mayer, ’99, p. 163, pl. 9, figs. 30, $7.
Eutima levuka, var. occellata Maas, : 05, p. 35, taf. 7, figs. 48, 44.

Plate 5, Figs. 2, 3; Plate 35, Figs. 1, 2.

Acapulco Harbor; surface; 3 specimens, all about 6 mm. in diameter.

The specimens all represent a younger stage than was observed either
by Agassiz and Mayer or by Maas, for they are considerably smaller (the
“Siboga’”” specimens, several of which were sexually mature, ranged from
12-20 mm. in diameter) and have only four tentacles. The number of ten-
tacles appears to be subject to great individual variation, since although
large specimens usually have eight, Maas (:05) has noted that they may
have only four or six; on the other hand, very small specimens may have
more than eight. The marginal bulbs have not yet attained their maximum
number, there being only eight to ten per quadrant, instead of sixteen to
twenty, as recorded by Maas (: 05, p. 36); but they, as well as the tentacles,
already show the adult structure, the former being flanked by a pair, the
latter by a larger number (three to five pairs) of cirri.

Maas (: 05, p. 36) considers the pigmentation of the rudimentary tentacu-
lar bulbs such a valuable specific character that he makes it the basis for
his new variety, Z. occellata. But it evidently is not so constant as he
supposed, for while all of the bulbs are deeply pigmented in two of our
specimens, in the third, equally well preserved, several of the bulbs are en-
tirely colorless and the pigmentation of the remainder is faint. Agassiz and
Mayer (99) do not appear to have observed any pigmentation in the Fiji
specimens.

Eutima levuka is apparently widely distributed over the Tropical
Pacific and Malaysian regions. No doubt when the Medusa fauna of this
region is more fully known it will be found to occur, in season, at many

localities besides those from which it has yet been recorded.

166 THE MEDUSAE.

It would be of much interest to know the true relationship of this form to
the three species from the Ceylon-Maldive region, Z. lactea Bigelow (: 04), H.
curva Browne (: 05°), and Octorchis orientalis Browne (: 05”). All of these are
undoubtedly closely allied to one another as well as to #. /evuka, but they ap-
pear to be separated from the latter by the condition of the marginal organs,
E. lactea having cirri flanking the tentacles, but not the marginal bulbs, while
in E. curva and Octorchis orientalis there are cirri flanking the papillae, but
none at the bases of the tentacles. 0. orientalis, and E. curva (known from
only one specimen) seem to be separable chiefly by the position of the
gonads; but since Maas (: 05) has found that in /. levuka gonads are some-
times developed on the peduncle in addition to those on the subymbrella, it
is questionable whether the difference in this respect is really of specific sig-
nificance rather than an indication of local, individual, or perhaps seasonal
variation. Unfortunately all of these species except /. devuka are known
from only a few specimens each. No final disposition of them is possible
until something is known of their life histories.

Eutimalphes Haeckel, 1879.

Eucopidae with gelatinous peduncle; with eight otocysts and numerous
tentacles.

Up to the present time, so far as I can learn, only three species have
been referred to this genus, viz., /. pretiosa Haeckel (’79), Ziaropsis mdicans
tomanes (’76), and Hvene coerulea L. Agassiz (62). The first of these, however,
seems to be closely related to Tima, for it has the extensive development of
lips characteristic of that genus, while Haeckel’s statement that it has only
eight otocysts is at least open to question, inasmuch as he himself says that
part of the margin of the single specimen was destroyed. Unfortunately
Romanes ('76, ’77) in the description of 7’. indicans gives no details as to the
tentacles or whether or not the margin bears either knobs or cirri; but
he explicitly states that there are only eight large otocysts, and his figure
(77, pl. 15, fig. 1) shows the long peduncle. The gonads also are repre-
sented as situated on the subumbrella and extending from the bell margin
to the base of the peduncle. #. coerulea L. Agassiz is the best-known mem-
ber of the genus. In this species the gonads extend over both subumbrella
surface and peduncle, the thirty-two tentacles are flanked by lateral cirri,
and there are a large number of rudimentary tentacular knobs in addition
to the developed tentacles.

EUTIMALPHES SCINTILLANS. 167

The collection contains a large series which, on account of the presence
of a peduncle, and the number of otocysts and tentacles, must be placed in
this genus; they differ so much from the foregoing forms, both in the
extent of the gonads and in the absence of marginal knobs and cirri, as
to justify making them the basis for a new species.

Eutimalphes scintillans, sp. nov.
Plate 5, Figs. 8, 9; Plate 37, Fig. 11.

Acapulco Harbor; surface; many specimens. Type 10 mm. in diameter.

The largest specimens are about 10 mm. in diameter by 5 mm. high.
The general form, with thin gelatinous substance and shallow bell cavity, as
seen in side view, is shown in the photograph (PI. 5, fig. 8). The peduncle
is short, only about 4 mm. in length in specimens 10 mm. in diameter, and
never, so far as I have observed, hangs below the opening of the bell. This
is considerably shorter than it is described by Romanes (’77) and Mayer
(:00°) for EL. mdicans and FE. coerulea. It is questionable, however, whether
this difference can be regarded as sufficiently constant to be of any spe-
cific value, inasmuch as Maas has shown that in Eirene the peduncle is
variable both in length and in outline. The manubrium is short and
nearly globular, the mouth surrounded by four short, simple lips. In this
character it, like the two species above mentioned, differs markedly from
E. pretiosa Haeckel.

Tentacles. —The largest number of tentacles observed was thirty-six, of
which two were evidently of recent growth, being much smaller than the
others. Most of the large specimens have from twenty-nine to thirty-two
tentacles, usually with two or three of them in early stages of growth.
The smallest number counted was thirteen, in a specimen some 2.5 mm, in
diameter. There are no tentacular knobs on the margin, except such grow-
ing tentacles as are mentioned above, nor do the tentacles bear lateral cirri
at their bases, such as Mayer has figured (: 00", pl. 11, fig. 22°) for E. coerulea.
The tentacles are short, and have swollen, conical bases. There are no
ocelli.

Otocysts. —There are eight otocysts, as is typical of the genus, two per
quadrant (Pl. 37, fig. 11). They are rather large, and contain each from

168 THE MEDUSAE.

two to five otoliths, After preservation in formalin for two years most of
the otoliths are destroyed.

Gonads. — All the specimens have gonads, though in the smaller ones
they are but slightly developed. Their position appears to be an important
specific character, for like the length of their extent along the radial canals
it is remarkably constant. They commence close to the bell margin and
occupy the distal one third to one fourth of the radial canal on the subum-
brella surface. None of the specimens showed any trace of the formation
of gonads on the peduncle. Even at early stages they occupy this same
portion of the canals, and they increase in size chiefly by thickening, their
increase in length only keeping pace with the general growth of the indi-
vidual. The series contains both males and females.

Color.—In life the gonads were pale green; in the preserved specimens,
however, both they and the manubrium have faded to a pale opaque yellow.

The absence of marginal knobs and of lateral cirri at the bases of
the tentacles, and the shortness of the gonads, clearly separate this species
from the West Indian form, Z. coerulea. The number of tentacles, though a
variable feature, may likewise prove to be of specific significance, since
L. Agassiz (62) states that in large specimens of LZ. coeru/ea measuring 1} in.
in diameter by 1 in. high there may be as many as thirty-five per quad-
rant. In specimens of £. coeruw/ea 10 mm. in diameter he counted only
thirty-two tentacles, but there were in addition ninety-six bulbs, which
may later develop into tentacles, thus producing the large number seen
in adults. The exact relation of LZ. scintillans to E. indicans cannot be deter-
mined until the marginal organs of the latter are more fully described, but
the form of the gonads and that of the peduncle appear to separate the two.

Octocanninae Maas, 1905.

Octocannidae Haeckel (’79).

Eucopidae with eight radial canals.

Octocanna Haeckel, 1879.
sens. em. Maas (:05); Browne (: 05°).
Octocanninae with eight simple radial canals; with well-developed manu-

brium with octagonal basal region; mouth with eight lips.

The descriptions of adult specimens of this genus by Maas (: 05) and

OCTOCANNA POLYNEMA. 169

Browne (: 05") entirely disprove the view advanced by Claus (’80) that
Octocanna is merely the young of Aequorea; and on account of the form
of the stomach and the determinate number of radial canals there is good
reason to believe that this genus is more closely related to the typical
Eucopidae than it is to the Aequoridae, with which it was classed by
Haeckel. The large number of canals, however, together with the presence
of excretory papillae and pores at the bases of the tentacles, suggest that
Maas (: 05, p. 38) is correct in calling it an “ Ubergangsgruppe” between
the two families. The discovery by Browne (: 05°) of small specimens of
O. polynema with only eight tentacles, though with developed gonads, shows
conclusively that Maas (:05) was correct in suggesting that O. octonema
Haeckel with eight tentacles was nothing more than the young of 0. polynema
Haeckel with sixteen or more tentacles. Since both the “Siboga”’ speci-
mens and those recorded from Ceylon by Browne (: (5°) are referable to
O. polynema, this species now stands alone in the genus. In the present col-
lection there are two specimens of Gctocanna of which the specific identity
is hard to determine. In several important features, especially in the
form of the bell, and in the having only eight tentacles, they differ from
adult O. polynema; but on account of the small number of specimens it is
possible that the final number of tentacles is not yet attained in spite of
the fact that the gonads contain large ova. For this reason it seems best to
class them provisionally as O. polynema, at least until their affinities can be
more definitely determined from the study of a larger series.

Octocanna polynema Haeckel.

Octocanna polynema Haeckel, 79 p. 214; Maas, :05, p. 38; Browne, :05°, p. 144, pl. 2,
figs. 8-10.
Octocanna octonema Haeckel, ’79, p. 215.

Plate 6, figs. 6, 10; Plate 38, figs. 1-4.

Acapulco Harbor; surface; 2 specimens, 10 mm. high by 8 mm. in
diameter.

In both specimens the gelatinous substance is so thick that the bell is
higher than broad, while the bell cavity is extremely shallow (Pl. 6,
fig. 10). In most of the specimens of O. polynema which have previously
been recorded the bell was rather low; but Browne (: 05°, p. 144) found a
single specimen in which the umbrella was very thick and the cavity of
the bell shallow. Apparently, then, the form of the bell, striking though

170 THE MEDUSAE.

it may seem in the present specimens, is not a constant nor an important
character.

Both the specimens have eight large radial tentacles, and between
every two tentacles from one to three triangular bulbs (PI. 38, fig. 2); but
there is no evidence that any of the latter are developing into tentacles.
Both tentacles and bulbs bear excretory papillae (Pl. 38, fig. 2, p. ex) on
the oral side of their bases, such as have been described by Browne (: 05”).
There are from three to five otocysts between every two radial tentacles.

The manubrium is very short, the mouth surrounded by eight pointed
lips (Pl. 38, fig. 2).

The specimens were entirely colorless in life.

These Medusae would readily be referred to O. polynema as immature
stages were it not for the fact that the gonads and ova are far ad-
vanced. As it is, it seems to me at least open to question whether the
rudimentary marginal swellings between the radial tentacles would in
the Acapulco form grow into tentacles; but it is impossible to answer
this without more material. Unfortunately it is exactly this information
which is requisite to determine their specific identity.

Aequoridae Eschscholtz, 1829.

sens. em. Maas (’93, : 05).

Leptomedusae with numerous radial canals (more than eight); with
numerous closed otocysts; tentacles with basal bulbs and excretory papillae.

There is no question but what Haeckel (’79) went much too far in split-
ting up this family, since some at least of his genera were undoubtedly
based on conditions of the stomach which were either accidental or
the result of contraction. On the other hand, Claus (’80) has probably
gone too far the other way in uniting all aequorids in the single genus
Aequorea. Browne (: (4, : 05") and Maas (:05), in recent publications, dis-
tinguish two genera, Aequorea with well-developed stomach and a mouth
capable of being closed, and Mesonema, in which the gastric wall is rudi-
mentary, and the mouth not capable of being closed but of almost as great
diameter as the stomach ; but although there are probably two (or even
more) genera of Aequoridae, this separation, based on the condition of the
mouth, seems to me no real advance over the previous attempts. In the
first place, 1 doubt whether the non-closable mouth actually occurs in any

AEQUORIDAE. lial

aequorid. The specimens on which both authors based their diagnoses were
preserved and therefore undoubtedly more or less contracted; furthermore,
neither Maas’s figure of J. macrodactylum nor the figures given by
Browne (: 05°, Pl. 2, figs. 11-15) of MZ. pensile seem to me to indicate such
a condition; indeed, in the former the gastric wall is but slightly nar-
rower than in the Atlantic species referred by Maas to Aeguorea for-
skalea (: 04°, Pl. 2, figs. 12-14). Finally, my own investigations on living
specimens of three species identified as A. macrodactylum, A. coerules-
cens, and A. tens, and on an undescribed species from the Gulf Stream,
show that the mouth may rapidly pass from the Aequorea to the Meso-
nema condition; and, perhaps most important, that when in the latter
condition, whether normally or as the result of preservation, there is often
no evidence, either in plications, folds, or obvious thickening, of contrac-
tion. Thus the Mesonema condition might readily be taken for the usual
one even if only momentarily assumed.

Though I am forced to conclude from these experiments that the
diagnosis of the two genera as expressed by Browne (: 05°) and by Maas
(: 05) is artificial, yet I believe it by no means improbable that the degree
of development of the mouth may yet be of generic importance in species,
such as A. (Zygodactyla) groenlandica, in which it is extensible as a long
manubrium or curtain. However, until some student is able to examine
larger series of living specimens I doubt whether any generic diagnosis
founded chiefly on this character will be of much value.

To retain any of the previous generic distinctions not only preserves an
unnatural order, but results in making any sound specific identification
almost impossible, since different individuals of a single swarm, or even one
individual under different external conditions or in different stages of con-
traction, might readily be referred to different genera; but to attempt
any generic revision of the members of this family without studying a
much larger series of living specimens than that to which I have had
access seems futile. It is to be hoped that such a study will soon be
made. In the meantime I believe that the most satisfactory course is to
recognize only one genus, Aequorea; though at the same time admitting
that this reduction is probably excessive, and that it is only temporary.

In identifying the two species of Aequoridae in the present collection
I have necessarily attempted a provisional revision of the Indo-Pacific

species; and although this is by no means final, I give it here, with-

172 THE MEDUSAE.

out attempting a correlation with the Atlantic species, in the hope of simpli-
fying the course of other students of this perplexing family.

First let us consider what characters may reasonably be supposed to be
of specific importance.

The number of tentacles is well known to be variable in all species, so
much so indeed that Claus (’80) and Browne discard it. I am inclined,
however, to think that if employed with caution it may be of some value.
Thus in Rhegmatodes tenuis A, Agassiz it is always small (forty-eight to
sixty-four); in Zygodactyla groenlandica always much greater (up to four
hundred). The proportional numbers of tentacles to canals is also sig-
nificant, for although Claus contends that it is so variable as to be of
no service yet all recent descriptions show that in Mesonema pensile
there are always many fewer tentacles than canals; in Zygodactyla groen-
landica and A. norvegica (Browne,:03) always many more; while in other
species the numbers are more nearly equal. My own studies suggest
that the proportion continues fairly constant with growth. A character
of great constancy and one not subject to much distortion with contrac-
tion, but the importance of which has been overlooked, is the diameter
of the stomach. Thus a very small stomach is constantly found in Rhegma-
todes tenuis and R, floridanus, a very large one in M. pensile. Finally, Browne
(: 03, :04,: 05°) has urged the taxonomic importance of the form of the basal
bulbs of the tentacles, and Maas (: 05), though admitting that they are subject
to contraction, believes them to be of value. In many species this is un-
doubtedly correct, and this discovery is an important advance. In others,
however, the bulbs are simply conical, so that they are not by themselves
distinctive, though in connection with other characters they may become so.

We may leave out of consideration Haeckel’s (79) genera Zygocanna,
Zygocannota, and Zygocannula, which are somewhat problematic, and have
not, so far as I am aware, been observed since first described; and the fol-
lowing species, A. ciliata Eschsch., A. ewrhodina Péron and Lesueur, and A.
thalussina Péron and Lesueur, which were founded on such unsatisfactory
figures and descriptions that identification with actual specimens is hopeless.
Fortunately the remaining Pacific forms are all fully described and well
figured. They seem to represent at least seven fairly well-defined species.

1. A species with very few (twelve to sixteen) tentacles in comparison
with a large number (ninety to one hundred) of canals; with very thick,

stiff, lenticular gelatinous dise, broad stomach, and tentacular bulbs with

AEQUORIDAE. 173

wings extending in either direction along the bell margin. This form was
first recorded from the Pacific as Polycunna purpurostoma Agassiz and Mayer
(99, p. 169); more recently, however, Browne (: 04) and Maas (: 05) have
identified specimens answering the same description with the Mesonema
pensile of Modeer. I have myself examined the type of P. purpurostoma,
and find that the basal bulbs, not especially described by Agassiz and
Mayer, are reducible to the type figured by Browne (: 04, pl. 57, figs.
6-8) and by Maas. Identical also with it, as Maas has shown, is Rhegmatodes
lacteus Agassiz and Mayer (: 02, p. 147). For this species the name J/.
pensile may be retained.

2. Mesonema macrodactylum Brandt has since been recorded by Goette
(86), Chun (’96), Agassiz and Mayer (: 02), and Maas (: 05), and is represented
by several specimens in the present collection. In this species each tentacu-
lar bulb bears a triangular spur-like process clasping the exumbrella; there
are about one half as many tentacles as canals. The species described by
Browne as Aequorea maldivensis has, as noted by Maas, the same form of
tentacular bulb and about the same proportional number of tentacles and
canals. The two are separable only by the form of the mouth, which is
described as slightly wider in A. ma/divensis than in MM. macrodactyhun ; but
since both Maas’s and Browne’s accounts were taken from preserved speci-
mens, and since in the present series of JZ. macrodactylum various breadths
of the lower gastric wall are represented, I have no hesitation in uniting
the two under the older name M. mucrodactyhun.

3. A. globosa Eschscholtz is recorded by Maas (: 05). Itis possible that one
of Browne’s specimens of A. ma/divensis with fifty tentacles and only fifty-four
canals, in reality belongs to A. globosa, In this species the number of tentacles
about equals that of the canals ; the basal bulbs are conical ; the stomach broad.

4. Rhegmatodes floridanus L. Agassiz. I have examined a series of this
species from Australia, from the Fiji Islands (Agassiz and Mayer, ’99),
as well as from the West Indies, and am unable to find any constant differ-
ences between the Atlantic and Pacific specimens. ‘The total diameter of
the stomach is very small; the number of canals is small, not as yet known
to surpass twenty-eight; the disc is thin and soft. This species is closely
allied to Rhegmatodes tenuis A. Agassiz, common along the east coast of
North America; but the differences in number of radial parts which separate
the two have been found to be constant in very large series by various

observers.

174 THE MEDUSAE.

5. Zygodactyla flava A. Agassiz. Mesonema victoria of Murbach and Shearer
is apparently identical with this species, whose account agrees even in minor
particulars with that of A. Agassiz (’65). In this species the number of tenta-
cles and canals (about equal) is very large (up to one hundred); and there is
a gelatinous peduncle.

6. Mesonema coerulescens Brandt, which, like Z. groenlandica A. Agassiz, has
many more tentacles than canals, and the basal bulbs laterally compressed.
It is probable that MJesonema dubia Brandt is a synonym of this form, as
Mertens believed (Brandt, 38, p. 362), but the description of JZ. dubia is not
sufficiently detailed for accurate determination.

7. A. conica Browne is easily distinguishable from any of the preceding
species by its short, deep, proximal gonads and by the high conical form of
the bell. Tentacles twenty-six to thirty, radial canals about sixteen. The
A. abbreviatum of Eschscholtz has a similar conformation of the gonads, but
the description and figures of it are so unsatisfactory that it seems impossi-
ble to determine whether or not it is synonymous with Browne’s species.

Finally, one more species has been described by Browne, A. parva, dis-
tinguished from all other Aequoride by having only four developed ten-
tacles; but since Browne himself has suggested (: 05°, p. 146) the possibility
that it may eventually develop more tentacles, its status cannot yet be
determined.

Aequorea macrodactylum Brandt.

Mesonema macrodactylum Brandt, ’38, p. 859, taf. 4; Maas, : 05, p. 40, taf. 8, figs. 52%, 57°.
Aequorea maldivensis Browne, : 04, p. 732, pl. 56, figs. 4-12.

Plate 36, Figs. 5-10.

Station 4667; surface; 1 specimen, fair condition.

Station 4668; 300 fathoms to surface; 1 specimen, good condition.
Station 4671; 500 fathoms to surface; 4 specimens.

Station 4676; 300 fathoms to surface; 1 fragmentary specimen.

Station 4679; 300 fathoms to surface ; 1 fair specimen.

Station 4683; 300 fathoms to surface; 1 specimen.

Station 4685; surface; 1 specimen.

Station 4728; 500 fathoms to surface ; 1 fragmentary specimen.

The specimens agree very well with the accounts given by Browne (: 04)

and by Maas (: 05) except that the number of radial canals and tentacles is

AEQUOREA MACRODACTYLUM. 175

rather smaller, as is the diameter of the bell. Browne records from
fifty-two to sixty-nine radial canals; and from twenty-one to fifty
tentacles; while Maas counted in various specimens from sixty-two
to one hundred and three canals and from sixteen to thirty tentacles.
The largest number of canals in any specimen in the present series
is forty-two, in an individual 22 mm. in diameter with about eighteen
tentacles. The smallest number observed was twenty-nine, with sixteen (?)
tentacles, in a specimen with no gonads, 8 mm. in diameter. In most
of the specimens the margins were so much damaged that it was impos-
sible to be confident of the complete number of tentacles; but appar-
ently they were never more than half as numerous as the radial canals.
Between every two tentacles are a considerable number (five to eight or
more) of rudimentary tentacular bulbs, much as Browne has figured them
for the Maldive specimens (: 04, pl. 56, figs. 70-12). The tentacular bulbs
are of an unusual outline, and it is largely because of their form that I have
identified the present specimens as A. macrodactylum. When seen from
without they are broadly triangular, and extend in a somewhat triangular or
spur-like process up over the exumbrella surface of the bell (Pl. 36, figs.
5, 6). This process shows especially well in a side view of the bulb
(Pl. 36, fig. 8). This is essentially the conformation described by both
Maas and Browne, and is apparently characteristic of all specimens, though
varying considerably as to the exact form of the exumbral clasp. In most
of our specimens this is less well defined, perhaps as the result of preserva-
tion, than Browne found it in the Maldive specimens. The essential sim-
ilarity of the bulbs in A. maldivensis and A. macrodactylum has already been
commented upon by Maas (:05). He has, it is true, considered these
two forms as belonging to different genera on account of differences in
the form of the mouth; but this is a difference which, as we shall see,
is of very little real importance.

Between every two tentacles there are from seven to fifteen otocysts,
a number agreeing with Browne’s account.

Gastrovascular system. — It was particularly fortunate that I was able to
study the collection in the fresh condition, for after preservation the lower
gastric wall is often so strongly contracted that if we recognized the char-
acter of the mouth as of generic importance we might readily class differ-
ent specimens in different genera. When first taken the usual condition of
the mouth was that shown in Pl. 36, fig. 9. I never saw any suggestion

176 THE MEDUSAE.

of such a proboscis as has been described for some other Aequoridae, nor
was the mouth closed in any of the specimens. In the preserved specimens
the mouth usually shows the Mesonema condition, with the gastric wall
forming merely a narrow fringe around the periphery of the stomach;
though in some specimens this wall is as broad as in life (Pl. 36, fig. 9).
The contraction is deceptive, for the wall shows no apparent evidences
of distortion, and might readily be supposed to be in its normal condition.
In comparing the figures of A. macrodactylum and A. maldivensis given by
Maas and Browne the only difference in the condition of the mouth is
that in A. maddivensis the gastric wall is somewhat broader than in A. macro-
dactylum ; and in view of the contractility of this organ, and the fact that
both descriptions were taken from preserved specimens, I am convinced
that this is due merely to the Maldive being less contracted than the
“‘Siboga”’ specimens. I may also call attention to the fact that the original
and very excellent figures of this species published by Brandt (’38) show the
lower gastric wall of considerable breadth, and by no means “ rudimentar ;
Mund daher fast so gross wie Magendurchmesser” (Maas, : 05, p. 40).

The small number of canals in the present individuals cannot, in my
judgment, be supposed to indicate specific difference from A. macrodactylum,
inasmuch as there is no evidence that any of our specimens had reached
their maximum development. The presence of gonads does not necessarily
indicate a close approach to maturity in this family, for it has been shown
that in several species a very considerable number of canals may be added
after the sexual organs on the earlier formed canals are of considerable size.
Fewkes (’81”) indeed has found that in A. groenlandica gonads begin to
develop when only a very few canals are formed. The sterile canals
described as alternating with fertile canals in various species are to be
thus explained; no doubt they would finally develop gonads. They are
particularly evident in medium-sized specimens of A. ¢enwis, and have been
firured by Maas (: 05) as well as by Brandt (’38) in A. macrodactylum, while
I have myself observed them in several of the present specimens.

All our specimens were entirely colorless, the gonads and entodermic
system opaque and milky.

Aequorea macrodactylum is widely distributed over the Tropical Pacific and
the Malaysian region; it has likewise been recorded from various stations
in the Indian Ocean (Maldives, Browne; Zanzibar, Chun, Goette).

AEQUOREA COERULESCENS. UT

Aequorea coerulescens Brandt.

Mesonema coerulescens Brandt, ’38, p. 360, taf. 5.
? Mesonema dubium Brandt, ’38, p. 361, taf. 26.

Plate 4, fig. 4 ; Plate 35, figs. 3-8.

Station 4652; 100 fathoms to surface; 1 large specimen, 60 mm. in
diameter.

Station 4655; 300 fathoms to surface; 1 specimen, 12 mm. in diameter.

The general appearance of this species is so well represented in Mertens’s
| beautiful figure (Brandt, ’38, taf. 5) that no extended account is necessary
| here. Certain details, however, need slight correction.

The gelatinous disc is thick, the bell shallow, in the adult specimen about
60 mm. in diameter by 20 mm. high.

Tentacles. — These are rather more numerous than Brandt believed
there being from three to six between every two canals, instead of only
two as Mertens represented them (Brandt, ’38, taf. 5, fig. 3), a total of
about four hundred and fifty. As Brandt states, the tentacles are of dif-
ferent sizes; they do not, however, form two distinct series as he supposed,

but large and small ones are irregularly arranged (Pl. 35, figs. 6, 8). Evi-
dently they merely represent different stages in growth, exactly the con-
dition that is to be seen in the Atlantic species A. groenlandica L. Agassiz.
In addition to developed tentacles there are a considerable number of
rudimentary bulbs (Pl. 35, fig. 5), which are most numerous on regions of
the margin where the tentacles are the least. crowded. The tentacular
bulbs are long, only slightly swollen, laterally compressed (Pl. 35, figs. 6,
7, 8), and very closely resemble the bulbs of A. groenlandica. Connected with
the inner side of each, at its base, is a prominent excretory papilla (Pl. 35,
figs. 6,7, p.ex). These organs are evidently the structures described by
Brandt as “tassenfirmiger, an Gestalt der Cupula einer Kichel nicht
unihnlicher Kérperchen” (’38, p. 361). The tentacles are short and
become exceedingly slender toward their extremities. In the small speci-
men the tentacular bulbs are of the same outline, a fact which has
rendered practically certain the specific identification of the specimen; but
the tentacles are much less numerous, there being in all only about one
hundred and forty, of which from forty-five to fifty are much larger,

and evidently of earlier origin than the remainder.
12

178 THE MEDUSAE.

Otocysts. — These are very numerous, but they are so crowded among
the tentacles that it is impossible to count them. Double examples are
often seen (PI. 35, fig. 5).

Gastrovascular system.— The stomach in the large specimen is about
30 mm. in breadth, 7. e. one half the diameter of the bell, and unchanged
in its preserved state from the condition seen while alive. The lower
gastric wall is well developed, far from rudimentary ; but the mouth never-
theless is widely open, although the gastric wall shows no sign of contrac-
tion. In view, however, of my observations on A. macrodactylum, I hesitate
to assume that it may not be much more extensible than it appears to be.
There are thirty-one lips or oral prominences, about one third as many
as there are canals. They are rather smaller than Brandt has figured
them (PI. 35, fig. 4), but the difference is not greater than might easily be
caused by slight contraction.

Canals. —In the large specimen there are ninety-four canals, which are
as obviously of different generations as are the tentacles. Many of them
are stout, and others very slender; but there is no definite arrangement of
different sizes. The irregular arrangement is clearly seen in the photograph
(Pl. 35, fig. 4). One of the canals is dichotomously branched near its base ;
all the others are simple. All of the larger canals bear gonads (which seem
to be mostly emptied of their contents), but many of the more slender ones
are sterile. This difference was noted by Mertens; but the two kinds of
canals are irregularly arranged instead of regularly alternating, as repre-
sented (Brandt, ’38). In the small specimen there are only forty-seven
or forty-eight canals, but they show the same divergence in size as do
those of the mature individual. Fourteen of the larger ones already bear
gonads; the remainder, however, are sterile.

Color. — Both our specimens show the characteristic pigmentation de-
scribed by Brandt, the tentacular bulbs being of a very deep bluish black,
which now after preservation is black and very opaque. Otherwise the
specimens are entirely colorless.

So far as I can learn, no undoubted record of this species has appeared
since its original description in 1838 by Brandt, for although a specimen
was recorded by me from the Maldive Islands (: 04, p. 256) under the name
A. coerulescens, its fragmentary condition made positive identification impos-
sible. The type specimen was taken by Mertens in the Pacific in about
35° N. and 144° W.

SARSIA COCCOMETRA. 179

ANTHOMEDUSAE.

Codonidae Haeckel, 1879.

sens. em. Vanhoffen (’89) ; Hartlaub (’07).

Anthomedusae with gonads in the form of one or more rings sur-
rounding the manubrium ; with simple unbranched tentacles; with simple
mouth opening without lips.

Sarsia Lesson, 1843.
sens. em. Hartlaub (’07).

Codonidae with four perradial tentacles, equally developed and armed
with nettle swellings; gonad in the form of a single ring or tube entirely
surrounding the manubrium, and not interrupted in either per- or inter-radil.
With or without stiel canal and apical projection. Exumbrella in adult
without nemocyst ridges, though these are often present in young stages.
Hydroid stage, the genus Syncoryne.

For a review of the present state of our knowledge concerning Sarsia I
refer the reader to the excellent summary and revision of Hartlaub (: 07).

Previously there have been described from the Pacific five species refer-
able to Sarsia : — S. rosaria A. Agassiz (65), S. radiata Von Lendenfeld (’84),
S. minima Von Lendenfeld (’84), S. apicula Murbach and Shearer (: 03), S. eci-
dentalis Fewkes (’89°), and S. species? Agassiz and Mayer (: 02). In addition
the common Atlantie S. eximia is now known, in the hydroid stage, from
Alaskan waters (Nutting, :01). The present collection contains specimens
of two well-marked species of this perplexing genus, both of which appear
to be undescribed. They are sufficiently distinguished by anatomical char-
acters from all the other Pacific species, but whether they are equally dis-
tinct from all of the numerous Atlantic forms is less certain.

Sarsia coccometra, sp. nov.
Plate 7, fig. 8; Plate 40, fig. 7; Plate 43, figs. 8, 9.
Station 4615; surface; 1 specimen.
Station 4617; surface ; 5 specimens.

Station 4619; surface; 3 specimens. Type.

180 THE MEDUSAE.

The largest specimen measures 5 mm. in height by 4 mm. in diameter ;

the smallest, 2 mm. high by 1.5 mm. in diameter. The bell has a triangular,
pointed, apical projection ; the gelatinous substance is very thin.

Tentacles. — The tentacles, when extended, are about as long as twice the
bell height. Close to the base they are naked; but for the remainder of
their length they are clothed with well-developed nematocyst swellings
which often form rings entirely surrounding them (Pl. 43, fig. 8). When
the tentacles are extended these rings present the appearance of strings
of small beads. At the tip of each tentacle is a broader terminal swelling
crowded with nematocysts. The tentacles arise from swollen bases, each of
which bears an ocellus on its outer (aboral) face (PI. 43, fig. 8).

The manubrium hangs about to the bell opening in all the specimens ;
but as in several it is evidently distorted by contraction, it is probable that
it could be considerably protruded in life. The mouth is surrounded by a
simple circular lip (Pl. 43, fig. 9). There is no peduncle. There is a broad
triangular, apical extension of the manubrium, above the level of the origin
of the radial canals, conforming in outline to that of the apical projection of
the bell, and at its tip sufficiently attenuated to suggest the remnants of the
“ stiel canal.”

Gonads. — A study of transverse sections of the manubrium has demon-
strated that the gonads are uninterrupted in either the perradial or interra-
dial planes, and are thus of the typical Sarsia type. In surface views of the
manubrium of several specimens there appear to be definite interradial
swellings (Pl. 40, fig. 9), which I at first believed indicated the location of
the gonads; but sections show that these apparent swellings are nothing
more than longitudinal ridges caused by contraction. In females the eggs
are very large. Two specimens had discharged their sexual products, leav-
ing the manubrium thin-walled and flexible. The gonads occupy nearly the
entire length of the manubrium, leaving only a short basal region bare.

Color. — In life the region of the gonads is reddish brown; the entoderm
of the tentacle bulbs Vandyke brown; the ocelli black (PI. 40, fig. 1).

Suarsia coccometra differs from the typical members of the genus in the
apical prolongation of the manubrium, in which it resembles Stauridium, and
in the possession of a well-marked apical projection, as well as in the high
development of the tentacular nematocyst bands. Its relationship, among
described genera, is evidently closest with Sarsia, and, on account of the

presence of the apical projection, with those species of the genus formerly

|

SARSIA RESPLENDENS. 181

grouped by Haeckel (’79) in the genus Codonium; but it is not unlikely
that its peculiarities may finally warrant instituting a new genus. It is
clearly separated from all of the various species of Sarsia found in the

Pacific.

Sarsia resplendens, sp. nov.
Plate 7, fig. 2; Plate 40, fig. 8.

Acapulco Harbor; surface ; 6 specimens.

The largest specimen (Type) is 2 mm. high by 1.5 mm. in diameter; all
have nearly mature gonads.

The bell is rather high, rounded, of about equal thickness throughout,
without any trace of apical projection or even of an aboral gelatinous thick-
ening. The exumbral surface is entirely smooth, the appearance of radial
nematocyst ridges seen in the colored figure (Pl. 40, fig. 8) being caused
merely by a wrinkling of the surface, due either to artificial or to muscular
contraction.

Tentacles. — The shortness of the tentacles is a very characteristic feature
of the species, and one unusual in Sarsia. Although the specimens were
studied alive the tentacles were never observed to extend to a length greater
than one half the bell height. The tentacles bear prominent nematocyst
swellings, which are variable in form, but never form rings; they are few in
number, six to ten per tentacle, corresponding to the shortness of the ten-
tacles. They occupy nearly the entire length of the tentacle, only a very
short basal region being naked (Pl. 7, fig. 2). At the tip of each tentacle
is a spherical nematocyst pad.

The tentacle bases are swollen and brilliantly pigmented; on the outer
surface of each is a large ocellus.

The manubrium is very short; in none of the specimens was it seen
to extend lower than the mid level of the bell; but inasmuch as it is
contractile, it may perhaps be protruded as far as the bell opening. It
varies greatly in form with different states of contraction. In four of the
specimens it is circular basally (Pl. 40, fig. 8); in two, however, it is con-
tracted so as to take a cruciform outline, the four ridges being perradial.
The mouth is circular, surrounded by a simple lip which may temporarily
assume a cruciform outline (Pl. 40, fig. 8). There is no trace of a “stiel
canal.”

182 THE MEDUSAE.

Gonads. — The gonad is in the form of a ring completely surrounding the
manubrium, which it clothes from its base almost to the lip.

Color.— This Medusa is most brilliantly pigmented. Near the base of
the manubrium there are eight adradial groups of vermilion and yellow
pigment granules; the entoderm of the tentacles is vermilion, surmounted
by a spot of ochre yellow; the ocelli are black; the ectoderm of the ten-
tacles and of the manubrium is milky white. This scheme of coloration is
constant in all six specimens.

Sarsia resplendens is related, by the shortness of its manubrium and its
total lack of apical canal, to S. dbrachygaster Grinberg (98), S. flammea
Linko (: 00), and S. angulatum Mayer (: 00°), species which Hartlaub (: 07)
suggests should be grouped together in a new genus distinguished from
typical Sarsia by these two characters; but from these, as well as from
all other species of Sarsia, it is sufficiently well distinguished by the
shortness of its tentacles, by the small number of tentacular nematocyst
pads, and by the brilliant and characteristic pigmentation.

Purena Hartlaub, 1907.

Codonidae with gonads in the form of separate rings surrounding the
manubrium ; long tentacles set with nettle swellings (not rings).

The necessity for a new genus to include those species of Sarsia and of
Dipurena which are separated from typical representatives of Sarsia by
having the gonads in the form of separate rings, and from Slabberia and
Dipurena by the long tentacles set throughout most of their length with
nettle swellings, was indicated by Browne (:05°). It was to fill this
want that Hartlaub (:07) has proposed the genus Purena.

The numerous examples of this genus in the present collection all
belong to one species identical with the Dipurena sp.? described from
Ceylon by Browne (:05"), to whose excellent account and figures
there is but little to add. Browne was unable to find any constant
character to separate this species from the European Sarsia strangulata
Allman (Dipurena ophiogaster Haeckel), and has given it no specific name.
There seem, however, to be certain differences in the form of the gonads,
which in the Indo-Pacific form are cylindrical rather than ovate, and in
the length of the manubrium, which is much shorter in the Indo-Pacific

form than in most of the figures of S. strangulata. Inasmuch as these

PURENA BROWNEI. 183

characters are constant in the present large series, it seems to me that they
are worthy of recognition, at least until the hydroid stage is known.

Purena brownei, nom. noy.
Dipurena sp. ? Browne, : 05>, p. 133, pl. 2, figs. 7, 2.
Plate 7, Fig. 7; Plate 44, Figs. 8-z0.

Mangareva Harbor; surface; many specimens. Type.

Acapulco Harbor; surface; 37 specimens.

The largest specimens measure 5 mm. in diameter.

The bell is moderately high and rounded; there is no apical projec-
tion; the gelatinous substance is rather thick (Pl. 7, fig. 7); the bell cavity
deep.

Tentacles. — The four tentacles when extended are much longer than the
height of the bell. Near their bases they are smooth (Pl. 44, figs. 8-10);
but throughout the rest of their length they are thickly set with oval, trans-
versely placed nematocyst clusters, which are irregularly arranged and
none of which form rings. The basal bulbs have been well described by
Browne (: 05”). They are globular, imbedded in the jelly (Pl. 44, fig. 10),
and surrounded basally by a circular swelling or band which is crowded
with nematocysts and bears a prominent ocellus on its outer face (Pl. 44,
fig. 10, 0).

The manubrium is moderately long, hanging a short distance below the
bell-opening. In the Ceylon specimens Browne has described it as rather
longer, “two to three times the length of the cavity of the umbrella”
(: 05°, p. 134); but in none of our specimens is it so long. At its proximal
end it bears a triangular projection into the gelatinous substance of the bell
(Pl. 7, fig. 7). The stomach proper is terminal, and barrel-shaped (PI. 7,
fig. 7). The mouth is circular, with simple lip.

Gonads. — The gonads form rings, which are entirely separate from one
another and surround the manubrium; I have not found them occurring on
the stomach proper. The number of rings is variable, the greatest number
counted being five, the least, one; and this variation is independent of dif-
ferences in the sizes of the medusae. The collection contains both males
and females.

Color.— The ocelli are yellowish, the gonads opaque white ; otherwise

the species is colorless.

184 THE MEDUSAE.

Purena brownei has a very wide range over the Pacific and Indian
oceans, a distribution suggesting that it reproduces by budding; but this

process has not yet been observed.

Ectopleura L. Agassiz, 1862.

Codonidae with either two or four perradial tentacles; tentacles with
nematocyst batteries on the outer face only ; manubrium short; exumbrella
with eight radial nematocyst ribs.

Four species of Ectopleura have been described : — 2. dumortii Van Bene-
den ('44), from the European coast, /. ochracea A. Agassiz (62), from the
Atlantic coast of North America, 2. minerva Mayer (: 00°), from the Tortugas,
and L. pacifica Thornely (: 00), from New Britain, the latter known from
the hydroid only.

EF. minerva is sufficiently well characterized by having only two tentacles.
E. ochracea and FE. dumortii are so closely allied that it is hard to find any good
characters to separate them ; indeed Dr. A. G. Mayer assures me that he was
unable to distinguish specimens of 2. dumortii taken off Cornwall from
EE. ochracea from New England.

The present collection contains a considerable series of the genus which I
have compared with numerous specimens of L ochracea, the result being that I
am unable to find any characters distinguishing the two except such as may
depend on state of contraction or on differences in preservation. I therefore
refer the Pacific series to 1. ochracea.

Ectopleura ochracea A. Agassiz.

Ectopleura ochracea A, Agassiz, 62, p. 343; ’65, p. 191, figs. 320-323; Hargitt, :05°, p, 32,
) ern ota

no tb eSElaioG: Wiehs, eee Figs. 12, 13.

Acapulco Harbor; surface ; many specimens.

The largest specimen measures 1 mm. in height by about 1 mm. in
diameter. ;

The bell is high; the gelatinous substance is thick at the apex but it
does not form a distinct apical projection. It is possible, as Hartlaub (: 07)
suggests, that the form of the bell may prove a good distinction between
this species and £. dumortii, in which it is rounded, not thickened, aborally.
In all the specimens there is a well-developed apical canal. The tentacles
of L’. ochracea are described (A. Agassiz, ’65, p. 191) as having the nettle

PENNARIA. 185

cells arranged irregularly, not in definite clusters as they are in 7. dumortii.
But in a series from New England, in the collection of the Museum of
Comparative Zodlogy, I have found them forming quite as definité swell-
ings along the outer sides of the tentacles as they do in the present
specimens (PI. 38, fig. 12). It appears, then, that this character is a
variable one, and therefore not of much taxonomic importance, At any
rate, specimens both from the Atlantic and from the Pacific exhibit the
same features in this respect. Hargitt (: 05°) has described ocelli in this
form; but in neither Atlantic nor Pacific specimens have I been able to
find anything more definite in the way of light perceptive organs than the
brilliant pigmentation in the centres of the basal bulbs of the tentacles.
‘E. dumortii is said to have no ocelli (Hartlaub, : 07).

Color. —I was unable to examine the specimens in life. After preser-
vation in formalin the manubrium is ochre yellow, the tentacle bulbs
pale yellowish. Preserved specimens from the Atlantic have about the
same color, but in life they are very brilliant, the tentacular bulbs being
yellow with bright red centres.

Pennaria Goldfuss, 1820.

Globiceps Ayers, 1852.

Codonidae with all four tentacles entirely rudimentary; manubrium
short, not extending beyond bell-opening; no ocelli. Hydroid stage,
genus Pennaria Goldfuss.

In this genus specific characters are to be sought in the hydroids rather
than in the very rudimentary medusae of those species in which they
are developed, and both hydroids and medusae, at least of P. tiarella, are
very variable. The present collection contains two species of Pennaria,
from widely separated localities, each represented by but a single speci-
men. One of these agrees so well with the account of P. vtrea Agassiz
and Mayer (99), from the Fiji Islands, that I refer it to that species. The
other most nearly resembles P. tiarella, yet differs from it in so many
respects that it probably belongs to a different species. As yet, so far as
I can learn, no species of this genus has been recorded from the west coast
of America although two species, P. rosea and P. adamsia, have been de-
scribed from Australia by Von Lendenfeld (84), so that there is no clue,
except that afforded by the medusa itself, to its identity, and since in this

186 THE MEDUSAE.

genus, where the medusae are little more than detached gonophores, such
clues, especially when taken from only one specimen, cannot be relied upon
without a knowledge of the hydroid, it is best to leave it for the present
without specific identification.

Pennaria vitrea Agassiz and Mayer.

Pennaria vitrea Agassiz and Mayer, ’99, p. 161, pl. 1, figs. 1-2.
Plate 7, Fig. 4.

Station 4696; surface; 1 specimen, 4 mm. high by 3 mm. in diameter.

These dimensions are slightly larger than those given by Agassiz and
Mayer, to whose account I have little to add. The specimen had discharged
its sexual products, and the manubrium was somewhat shrivelled. The
four tentacular bulbs are extremely rudimentary; exumbrella surface
smooth; radial canals unpigmented.

Color.—The tentacle bulbs are yellowish; the manubrium opaque and
milky. Agassiz and Mayer (’99) state that the entoderm of the manubrium
in both sexes is green; but Hargitt has shown that color is a variable
character in this genus.

Pennaria species ?

Plate 7, Fig. 6; Plate 40, Fig. 7.

Acapulco Harbor; surface; one specimen, 2 mm. high.

This specimen, which had discharged its sexual contents so that the
manubrium is much shrivelled, closely resembles the medusae of P. tea
rella, which I have examined in large numbers, except for its more bril-
liant coloration, and for the fact that the radial canals have swellings
about midway of their lengths. These swellings appear to have nothing
to do with the formation of sexual products, but are merely crowded with
pigment granules.

The bell is high and narrow; the gelatinous substance stiff and opaque ;
the tentacle bulbs very rudimentary; the manubrium about half as long as
the bell height.

Color. — The color of this Medusa is very brilliant, the manubrium and
radial canals being brick-red. Tentacle bulbs colorless.

This specimen differs from any Medusa previously referred to Pennaria ;

ZANCLEA. 187

but it seems hardly more serviceable to describe it as a new species without
the knowledge of the hydroid than it would be to name a new siphonophore
from the medusoid gonophore alone.

Cladonemidae Haeckel, 1879.
sens. em. Vanhoffen (’89); Hartlaub (:07).

Anthomedusae in which the tentacles are either branched, or bear
stalked cnidoblasts ; with 4-8 radial canals.

Zanclea Gegenbaur, 1856.
Gemmaria McCrady, 1857.

sens. em. Hartlaub, : 07.

Cladonemidae with either two or four hollow tentacles, which bear on
the aboral side nematocysts mounted on contractile filaments; four simple
radial canals; manubrium without apical extension ; gonads primarily inter-
radial; no ocelli.

This definition is that proposed by Hartlaub (:07). Hargitt (:08), who
agrees with him in uniting Gemmaria with the genus Corynites as defined
by A. Agassiz ('65) and later authors (non Corynites McCrady), believes
that the number of tentacles is a character of sufficient importance to
warrant the retention of Gemmaria with two, as distinguished from Zanclea
with four; but although he found only two tentacles in the Mediterranean
species Z. implexa Alder, Hartlaub (:07) has recorded four tentacles in
occasional very large specimens of this species. | However, as Hartlaub
(: 07) says, the question is still an open one; and the present series does not
supply the answer.

The medusae of the various species of Zanclea are so similar one to
another that it is difficult to find satisfactory characters by which to
separate them; for the certain identification of a given series a knowledge
of the hydroid stage is essential. Characters which have been regarded as
of taxonomic importance in the medusae are the form of the bell, the form
and extent of the exumbral nematocyst ridges, the form of the tentacular
nematocyst batteries, the structure of the mouth, whether with or without
lips, and the number of tentacles; but this last character, as pointed out
above, may perhaps be of generic significance.

The present collection contains five specimens, which closely resemble

188 THE MEDUSAE.

Z. gemmosa McCrady, except that the exumbral nettle ridges are rather
longer. This slight difference seems hardly sufficient to warrant specific
separation, especially inasmuch as the specimens were not examined until
after preservation. It would be most interesting to know the relation of
the present medusae to the hydroid stage described from Juan Fernan-
dez by Hartlaub under the name of Z. wtida; it is possible that the two
Pacific forms may prove to represent but one species.

Zanclea gemmosa McCrady.

Zanclea gemmosa McCrady, 757, p. 151, pl. 8, figs. 4, 4.
Gemmaria gemmosa McCrady, °57, p. 151; A. Agassiz, ’65, p. 184, fig. 306; Mayer, : 00°,
p. 35, pl. 41, figs. 187, 138.

Plate 7, Fig. 3; Plate 44, Figs. 1, 2.

Acapulco Harbor; surface; 5 specimens.

The largest specimen is 1 mm. in diameter.

As in Atlantic specimens the gelatinous substance is thin and the bell
rounded, an outline very different from that of Z. cladophora A. Agassiz,
in which the gelatinous substance is thick. There are two stout perradial
tentacles, and alternating with them there are two small tentacular knobs.
Since these latter structures are very rudimentary in all the specimens,
although several have mature gonads, it is probable that they do not
develop into tentacles. In the contracted condition of the tentacles it is
impossible to distinguish the normal form of the nematocyst batteries or
enidoblasts, which are closely crowded along their aboral sides (Pl. 44,
fig. 1), or to determine the extent to which their fibrils are extensible.

The manubrium is sac-like, hanging about to the opening of the bell
when extended; the mouth is surrounded by a simple circular lip (Pl. 44,
fig. 2).

The gonads are probably primarily interradial, as in other members of
the genus (Vanhiffen, ’89; Hartlaub, :07); but in the female the eggs
grow so large that they obscure this arrangement, and finally come to
occupy the entire wall of the manubrium (PI. 44, fig. 2). In the male. the
location of the sexual products seems to remain permanently interradial.

Color.— The manubrium and the swollen bases of the tentacles are

salmon pink,

CYTAEIS. 189

Cytaeidae L. Agassiz, 1862.

Anthomedusae with interradial gonads; with solid tentacles; with labial
nettle knobs or tentacles; marginal tentacles simple, not in groups.

As thus defined, the family includes not only the Thamnostomidae
Haeckel, Podocorynidae Hincks, and Cytaeidae L. Agassiz, already united
under the name Podocorynidae by Délage et Herouard (: 01), but also the
Dendroclavidae. Délage et Herouard retain the latter group as a separate
family, on account of the presence in it of a peduncle of peculiar chordate
cells; but the degree to which this structure varies in the various species
of the genus Lymnorea (p. 193), indicates that it is not a character of the
importance they supposed. In all other respects Cytaeidae and Den-
droclavidae are much more closely related to each other than is either to
any other family; so closely, indeed, that their natural relationships are
probably better expressed by reducing them to the rank of subfamilies of
the one family, rather than retaining them as separate families.

Cytaeinae.
Cytaeidae Haeckel (’79); Maas (: 05).
Cytaeidae with simple marginal tentacles, not in groups; labial nettle
swellings stalked (forming tentacle-like structures). No peduncle.

Cytaeis Eschscholtz, 1829.

Labial tentacles simple; marginal tentacles permanently four, stout, solid.

Maas (: (4°) has pointed out that the several Atlantic species of this
genus which have been described are certainly not all distinct, C. ¢etrastyla
Eschscholtz being probably an immature stage of C. nigritina Steenstrup,
while C. pusilla is certainly a very young stage, and perhaps belongs to this
same species. C. macrogaster Haeckel seems to Maas well founded, because
of the size and shape of the stomach. From the Indo-Pacific region two
species have been described: C. vulgaris Agassiz and Mayer ('99), and C.
herdmani Browne (: 05°). Since the present series shows intermediate stages
between the two, it appears that they in reality represent only a simple
species, for which the older name C. vulgaris must be retained. In addition
to the species above mentioned Mayer (: 00°) has referred still another, C.
gracilis from the Tortugas, to this genus; but inasmuch as this form already
has eight tentacles at the stage when the first medusa buds are formed, it

clearly does not belong to Cytaeis.

190 THE MEDUSAE.

Cytaeis vulgaris Agassiz and Mayer.

Cytaeis vulgaris Agassiz and Mayer, ’99, p. 161, pl. 2, figs. 3-5 ; Maas, : 05, p. 8, taf. 1,
figs. 4-7.
Cytaeis herdmani Browne, : 05», p. 135, pl. 1, fig. 7, pl. 4, fig. 72.

Plate 6, Fig. 3; Plate 40, Figs. 2, 5+ Plate 43. Fig. 4.

Station 4644; surface

Station 4646; surface

Station 4646; 300 fathoms to surface

Station 4648

Station 4655

Station 4667

Station 4678

Station 4681 At stations 4646 and 4648

: All at surface

Station 4682 swarms; at each of the other

Station 4694 stations several specimens were

Station 4704 taken.

Station 4712

Station 4716

Station 4717; 300 fathoms to surface

Station 4731; surface

Station 4733; surface

Station 4735; surface

Station 4741; surface

The series is of various sizes up to 5 mm. in diameter.

The general characteristics of this widely distributed Indo-Pacific species
have been so well described by Agassiz and Mayer (’99, : 02), by Maas (: 05),
and by Browne (: 05”), that repetition here is unnecessary. Reference must,
however, be made to the number of oral tentacles, since Browne has main-
tained that the great number (fifty to sixty) of these organs in his speci-
mens is distinctive of C. herdmani. In the present series the number proves
to be very variable, yet in general increasing with the growth of the Medusae.
The maximum observed, in a specimen 5 mm. in diameter, was forty-two,
thus approaching so closely to Browne’s minimum that I have no doubt as to
the common identity of Pacific and Ceylon specimens. Maas counted only
thirty-two; Agassiz and Mayer in their largest individual only sixteen.
Small specimens have even fewer, their least advanced specimen having
only four (Agassiz and Mayer, ’99).

CYTAEIS VULGARIS. 191

A second feature thought by Browne (: 05°) to distinguish C. herdmani
from the Atlantic species C. nigritina and C. macrogaster is the structure of the
tentacles, in which in @. herdmani the pigment is restricted to the endoderm
cells; but since these same conditions appear to occur in the “Siboga”
specimens of C. vulgaris, it gives no ground for a specific separation of C.
herdmani from C. vulgaris. In size the present series agrees closely with Maas’s
account, the largest individual in this, as in the “ Siboga”’ collection, measur-
ing about 5 mm. in diameter.

Maas and Browne both took their accounts from specimens with sexual
products in process of development, and neither they nor Agassiz and Mayer
observed budding, although Maas (:05) has suggested that such a process
probably occurs. In the present series, however, most of the specimens (all
the larger ones) show stages in budding, while none bear any trace of
gonads. The buds, as is usual in the Anthomedusae, are borne on the walls
of the manubrium, and in the larger specimens crowd it densely (Pl. 43,
fig. 6). In its details the process of budding presents no remarkable fea-
tures, but agrees closely with similar stages in the Atlantic C. nigritina. It
is of importance to know that this method of sexual reproduction occurs
in C. vulgaris, since it allows us to look at its geographic distribution from a
point of view quite different from that to which we must needs be limited,
did we suppose its only mode of multiplication to be the sexual process
with a fixed hydroid stage. Knowing that budding does occur, it is not
surprising that the species is found to range over the whole Tropical Pacific
and Indian oceans.

Color.—In life the coloration of this species is brilliant. The en-
todermic core of both tentacles and tentacular bulbs is deep salmon or
chocolate red, their ectodermic sheaths pale lemon yellow; manubrium pale
salmon red. This does not altogether agree with the account given by
Agassiz and Mayer, for they found only the basal bulbs of the tentacles and
the base of the proboscis red, the tips of both organs being greenish; but
since their account was taken from small specimens it is probable that the
difference is due to difference in the stage of development. The descrip-
tions of Maas (: 05) and Browne (: 05") were taken from preserved material
in which most of the color had been lost.

192 THE MEDUSAE.

Dendroclavinae.
Dendroclavidae Vanhiffen (’89); Délage et Herouard (: 01).

Cytaeidae with the labial nettle swellings sessile; with more or less pro-
nounced peduncle composed of chordate entoderm cells.

The best known genus of this subfamily is Turritopsis, a representative
of which, 7. nutricula McCrady, is common along the east coast of North
America, and has been described in great detail by Brooks (’86).

Other forms, allied to Turritopsis, but generically separable from it on
the one hand by a less pronounced development of the peculiar peduncle
and on the other by greater complexity of the labial nematocyst knobs,

have recently been described by Mayer (: 00%) and by Broch (: 08) as species °

of Limnorea Péron et Lesueur. Whether or not these forms are actually
congeneric with the Z. ¢riedra of Péron et Lesueur is extremely doubtful,
for the description of the latter is most unsatisfactory, while the figure by
Lesueur (published by Milne Edwards ’49) is so evidently distorted as
regards manubrium and mouth-arms that any identification of it with actual
specimens is apparently out of the question.

Very recently Brooks and Rittenhouse (: 07) have suggested the generic
name McCradia for “‘a number of medusae, from various parts of the world,
which are very similar to Turritopsis, . . . and are placed together in the
genus Modeeria” (: 07, p. 435). The member of this genus which they
figure (: 07, pl. 31, fig. 8), though without specific name, is evidently congen-
eric and probably conspecific with Lymmnorea alexandri Mayer (: 04), and is
from near the type locality of that species. Apparently they have over-
looked the fact that both Broch and Mayer had already used the name
Lymnorea for the Medusae which they call McCradia.

There is reasonable doubt as to whether Lymnorea or McCradia is
the better name for this genus. On the whole, however, it seems that the
former has the stronger claim, since both Mayer’s and Broch’s descrip-
tions antedate Brooks and Rittenhouse, and are so good as to leave no
doubt as to the generic identity of their specimens. In this case, how-
ever, Lymnorea must be dated from Mayer (:00*), not from Péron et
Lesueur, as the L. ¢riedra is unrecognizable. Since no species seems to have
been designated as its type, I suggest Z. alexandri Mayer.

In so far as regards the position of the gonads, Brooks and Rittenhouse

at an A RE

LYMNOREA ALEXANDRI. 193

take a stand opposite to that held by Vanhéffen (’89), maintaining that
these organs, as Haeckel (’79) supposed, “are, no doubt, fundamentally radial,
but the halves are pushed apart by the channels through which the radiat-
ing canals open into the stomach, so that each half joins the half of the
adjacent reproductive organ in the interradial plane. There are, in effect,
four interradial gonads, although each is to be regarded as the halves of
two perradial gonads” (Brooks and Rittenhouse, :07, p. 455). They have
offered no evidence, however, that this is the actual course of development,
while their own figures suggest that the gonads are truly interradial, since
they are perfectly continuous in the interradii, while entirely discontinuous
in the perradii. The fact that the furrows in the interradii along which
they suppose the union of the gonads to have taken place are deeper in
adults than in the young is further evidence in support of the latter expla-
nation. What little evidence is afforded by the present specimens, as well
as by a series of Turritopsis nutricula which I have myself examined, is to
the same effect, 7. e. that the gonads are interradial.

Lymnorea Mayer, 1900.
(Non Péron et Lesueur, : 09.)

Dendroclavinae with but slight development of peduncle; with numer-
ous tentacles; oral nematocyst knobs numerous, and branched.

The four species of Lymnorea, as thus limited, Z. borealis Mayer (:00*),
L. ocellata Agassiz and Mayer (: 02), L. norvegica Broch (: 05), and L. alexandri
Mayer (: 04), are distinguished from one another only by such minor charac-
ters as number of tentacles, length and form of proboscis, and extent of
branching of the labial arms, characters all of which change with growth.
It is doubtful whether all the species are distinct; but it is impossible to
revise them from the published accounts. The description of L. alexandri
agrees so well with the specimens in the present collection that I have little
hesitation in referring them to that species.

Lymnorea alexandri Mayer.

Lymnorea alexandri Mayer, : 04; p. 10, pl. 1, figs. 7-6*.
McCradia species Brooks and Rittenhouse, : 07, p. 435, pl. 31, fig. 8.

Plate 40, Figs. 3, 4; Plate 44, Figs. 11, 12.

Acapulco Harbor; surface ; 4 specimens.

The largest specimen measures 2.5 mm. in height by almost 2.56 mm, in

13

194 THE MEDUSAE.

diameter, and has forty-six tentacles. The smallest is about 2 mm, high,
with thirty-three tentacles.

The bell is high ; its apex flattened ; the gelatinous substance thin.

The tentacles are solid, about as long as the bell height; coiled spirally
when contracted. They have swollen bases, each of which bears an ocellus
on its inner (velar) side.

The manubrium is highly contractile; it does not extend to the bell-
opening. After preservation it presents the condition represented in Pl. 44,
fig. 12. The mouth arms are more simple than they are described for
any adult species except L. borealis, being very short, and each branching
only twice, so that at each corner of the mouth there are four nettle knobs
(sixteen in all). The peduncle of chordate cells, so well described by Brooks
and Rittenhouse, is short (Pl. 40, fig. 3), and in preserved specimens almost
entirely masked by the contraction of the manubrium.

Gonads. —The gonads are interradial, and entirely discontinuous in the
perradii (Pl. 44, fig. 12). They are oval and prominent.

Color.—The gonads are pink, tentacle bulbs reddish, ocelli black (PI.
40, figs. 3, 4).

The specimens closely resemble Mayer's (:04) account of LZ. alexandri
except that the branching of the labial tentacles is less complex, there being
only four instead of eight knob-like terminations to each; but the fact that
there are many small marginal tentacles among the larger ones suggests
that specimens have not yet reached the final stage in their development so
that further development of labial tentacles might be expected.

The specimen figured by Brooks and Rittenhouse presents an even sim-
pler condition of the mouth arms, which are simply bifid. Inasmuch as
Mayer has found that the branching of these organs increases in complexity
with growth, we may assume that the three conditions represent as many
stages in development, rather than specific differences. In all the bell is
high and flattened, manubrium short, and the peduncle much reduced.

In L. ocellata Agassiz and Mayer (: 02), from the Paumotus Islands, the
gelatinous peduncle is longer, the basal dilations of the radial canals being so
prominent as to more nearly resemble the condition in Turritopsis. The
labial arms likewise are more highly developed, the branching progressing
even further, and the arms themselves being long and tentacular instead
of mere nematocyst knobs. Furthermore, the tentacles in this species are
described as short and stiff. It is possible that these differences are to be

BOUGAINVILLEA FULVA. 195

explained as concomitant with a still more advanced stage in growth. I
hesitate, however, to unite the two species until more specimens of the
L. ocellata form are examined, or until such individuals are found within
the range of L. alexandri.

L. borealis Mayer (: 00*) has a much longer manubrium, and the peduncle
even more reduced than in either L. alexandri or L. ocellala; but since only
three specimens of this species, all males, were examined, it is an open ques-
tion whether these differences are constant. The description by Broch
(: 05) of LZ. norvegica is brief and without figures; but it appears that this
species most closely resembles Z. borealis in the small number of tentacles,
length of manubrium, and simplicity of labial arms.

Bougainvilleidae Gegenbaur, 1856.
Vanhoffen (89); Maas (: 05).
Hippocrenidae McCrady, 1857.

Anthomedusae with four interradial gonads ; with branched labial ten-
tacles; marginal tentacles in bundles.

The family divides into three sections according as there are four, eight,
or sixteen groups of tentacles. The genera of the last two groups, Rathkea,
Lizzia, and Chiarella, are sufficiently well defined, but those of the first,
Margelis, Bougainvillea, and Nemopsis, merge into one another to such
a degree that it is doubtful whether they should represent more than one
genus. The final answer to this question cannot be given, however, until
more thorough comparative studies have been made, and especially until the
life histories of the various species, their hydroid stages, and the changes
which the medusae undergo with growth, have been traced. The family is
represented in the “Albatross” collection by a series referable to Bougain-
villea fulua Agassiz and Mayer.

Bougainvillea fulva Agassiz and Mayer.

Bougainvillea fulva Agassiz and Mayer, 99, p. 162, pl. 2, fig. 6; : 02, p. 145, pl. 2, fig. 8;
Maas, : 05, p. 10, taf. 1, fig. 8, taf. 2, figs. 9, 10; : 06°, p. 87, pl. 2, figs. 4, 5

Plate 6, Fig. 7; Plate 44, Figs. 5-7.

Acapulco Harbor ; surface ; many specimens, from 1 to 7 mm. in diameter.

The specimens range from very small up to about the stage represented

196 THE MEDUSAE.

by the Amboina specimens recently described by Maas (: 06°). The collec-
tion from the ‘‘Siboga” (Maas, :05) belongs to a still further advanced stage.
The bell is higher than broad, the gelatinous substance thick, especially at
the apex. Maas (: 08, p. 11) states that in large individuals the outline is
somewhat prismatic; but the great majority of the present specimens are
circular in cross section, although a few are more or less distorted by
preservation.

The largest number of tentacles per bundle in our series is thirteen (Pl. 44,
fig. 7), imaspecimen 7 mm. high. Maas (: 05) has noted twenty in still larger
specimens. In specimens 1-2 mm. in diameter there are only three or
four per bundle ; but the number increases steadily with growth. It appears
that shortness of the tentacles is distinctive of this species, as Maas has
suggested, for even in life I have never seen them reach a length greater
than one half the height of the bell. Such excessive reduction of these
organs as he has figured (: 05, taf. 1, fig. 8) for the ‘Siboga ” specimens is
probably due in part to contraction and preservation. The ocelli lie on the
inner (oral) faces of the tentacular bases; but I have seen no actual evidence
that this location is associated with a habit of carrying the tentacles curved
upward as he has suggested, and as Agassiz and Mayer have figured them
(: 02, pl. 2, fig. 8). On the contrary, in life the tentacles were very flexible,
being alternately expanded and contracted, and often streaming behind the
bell, as in the common B. superciliaris from the Atlantic.

The form of the manubrium is variable. Maas has already noted that
“Man kinnte das lebende Tier . . . fiir eine Margelis, das conservierte fiir
eine Hippocrene halten” (:05, p. 11), the manubrium in life being long,
after preservation very short. This species, when small, passes through
what may be called a Margelis stage. In the smallest specimens the manu-
brium is barrel-shaped, its base being narrow. In larger specimens it is
broader basally, though showing much variation with different degrees of
contraction. In the largest specimens its base becomes very broad, an
outline associated with the appearance of the gonads; as Maas has
shown, even when it is broadest the radial canals do not originate at its
corners, but can always be traced to its centre where they meet in a cross.
In outline, as viewed aborally, the manubrium of larger specimens varies
from nearly circular to cruciform, a variation correlated with contraction
and perhaps with the state of nutrition of the organ. The mouth is usually
cruciform (Pl. 44, fig. 6).

AMPHINEMIDAE. 197

Color.— The base of the manubrium and the tentacular bulbs in the
Acapulco specimens varied from yellowish green to ochre yellow; they are
described by Agassiz and Mayer as rosin yellow (: 02, p. 145). The tentacles
are milky ; the bell is transparent.

This species is widely distributed over the Tropical Pacific Ocean and
the Malaysian region.

Amphinemidae Haeckel, 1879.

sens. em. Vanhoffen, ’89.

Anthomedusae with interradial gonads and with hollow tentacles ; with
only two developed tentacles, although there may also be numerous rudi-
mentary tentacles.

This family was included by Haeckel (79) in the Tiaridae as a subfamily,
but we may well follow Vanhitfen (’89) in classing it as a separate family,
for, although it is more closely allied to the Tiaridae, from which it is to be
distinguished only by the restricted number of tentacles, than it is to any
other family of Anthomedusae, its members form an extremely homogeneous
group. ‘This classification is likewise accepted by Maas.

Vanhéffen has united the three genera of Amphinemidae which Haeckel
distinguished under the oldest name, Stomotoca, believing that the
differences in the extent and form of the gonads which formed Haeckel’s
basis for separating Amphinema from Codonorchis are merely the expression
of different stages in development, and that the presence of a gelatinous
peduncle which serves to characterize Stomotoca is at most of specific, not
of generic, importance. With the union of Amphinema with Codonorchis
I entirely agree. According to Haeckel the gonads of the former are
restricted to the walls of the manubrium, while in the latter they extend
from the manubrium over the surface of the subumbrella; but since in at
least one species in the present collection, A. twrrida Mayer, moderate-sized
individuals show the former, larger ones the latter condition, it is evident
that the difference represents nothing more than successive stages in devel-
opment, and therefore should not be given generic significance. It may be,
however, a specific character, should it prove that the simpler condition is the
final one in any species of the genus. The ground for Vanhéffen’s com-
bination of Amphinema with Stomocota is less certain. A peduncle, when it

occurs, is a very constant character; and, inasmuch as it distinguishes several

198 THE MEDUSAE.

species, may reasonably be accorded generic value. I therefore retain two
genera in this family, Amphinema and Stomotoca.

Amphinema Haeckel, 1879.

Amphinemidae without gelatinous peduncle.

Probably there are described five or six species which must be referred
to this genus, but it is questionable whether all of them are distinct. Three
have been described from the South Atlantic coast of North America,
and are recorded by Mayer under the names Sfomotoca apicata McCrady
(57), Stomotoca rugosa Mayer (:00*), and Stomotoca australis Mayer (: 00).
Inasmuch as the present collection contains several specimens which agree
closely with Mayer's latest figure of S. australis (: 04, pl. 1, fig. 9), I have at-
tempted to reach a decision as to the relationships of these three forms,
which present rather a confused case of synonymy. The earliest account of
any American species is that by McCrady (57, p. 129) of Saphenia apicata,
since recorded by Agassiz (’65), Fewkes (’81), Brooks (’85), and Mayer (: 00°).
But Mayer (:00*) contends that the S. apicata of Fewkes (81) and Brooks
(83) is in reality a different species to which he has given the name
S. rugosa, and that the Dinatella cavosa of Fewkes ('81) is identical with
S. apicata McCrady.

Mayer, in distinguishing S. apicata from S. rugosa, lays stress on the differ-
ence in color, the tentacle bulbs of the former being purple or ochre accord-
ing to the sex, and of the latter brick-red, a difference which appears to be
fairly constant and on the more complexly folded lips of the latter; but in-
asmuch as McCrady describes the basal bulbs of his original specimens of S.
apicala as red, it seems doubtful whether Mayer’s choice of names for the two
is correct. S. australis Mayer (: 00") very closely resembles S. apicata, indeed
his figures of the two agree almost exactly, except that the former has defi-
nite brilliant red ectodermic ocelli at the bases of the rudimentary tentacles,
while in the latter there are no ocelli but only seattered entodermic pigment
granules ; this difference Dr. Mayer assures me is a very constant one. We
cannot hope to reach any definite and lasting conclusion as to the inter-
relationships of these three forms until the hydroid stages of S. apicata and
S. australis ave known; that of S. rugosa according to Mayer (: 00°, p. 33)
is a Perigonimus much like P. minutus Allman (71). In the meantime it

seems best to retain all three names. In all these forms, and in the A.

|

AMPHINEMA AUSTRALIS. 199

dinema from the coast of Europe, which is very closely allied to them, the
gonads appear to be permanently limited to the manubrium.

One other American species, Dissonema turrida Mayer (: 00°), must also
be referred to Amphinema. This species was placed by Mayer in the
leptomedusan genus Dissonema on the supposition that the gonads were not
situated on the walls of the manubrium, but lay along the radial canals.
An examination of Mayer’s original specimens has convinced me that this
interpretation is erroneous, and that the gonads in reality belong to the
walls of the manubrium, whence, in large specimens, they extend out on to
the subumbrella, exactly as Haeckel (79) describes them in Codonorchis.

The present collection contains two species of Amphinema, one identical
with A. australis Mayer, the other with A. turrida Mayer. The series of the
latter is particularly instructive, since it illustrates several successive stages
in the growth of the gonads.

Amphinema australis Mayer.

Stomotoca australis Mayer, : 00, p. 32, pl. 1, fig. 2; :04, p. 9.

Plate 7, Fig. 5; Plate 38, Figs. 10, 11.

Acapulco Harbor ; surface; many specimens.

The largest specimens measured 3 mm. in height by 2.5 mm. in diameter.

The specimens agree very closely with Mayer's account, and the general
form, with high apical projection, is well shown in his figures. In the photo-
graph (PI. 7, fig. 5) this is much less prominent than in life. The presence
of ectodermic ocelli at the bases of the rudimentary tentacles is a distinguish-
ing feature of this species, and one very constant in all the specimens. The
number of rudimentary tentacles is also important, for I have never found
more than six, even in large individuals with ripe sexual products, while in
A, rugosa, according to Mayer (: 00°), there may be as many as fourteen.

The gonads, not shown clearly in Mayer’s figures, are interradial (Pl. 38,
fig. 11), though in large specimens only slightly interrupted in the perradii.
They are always smooth, without distinct folds or lobes such as are found in
A. turrida, and are restricted chiefly to the basal region of the manubrium.
The collection contains both males and females. While in 8S. apicata the
two sexes differ from each other both in color and in form (Mayer : 00*), in

S. australis they are indistinguishable externally.

200 THE MEDUSAE.

The lips, though simple, are considerably longer than Mayer has repre-
sented them, and extend almost across the bell cavity.

Color. — The ocelli are reddish brown, the manubrium and gonads faintly
greenish, This is the same color that Mayer has recorded. This species has
previously been recorded from the West Indian region only.

Amphinema turrida Mayer.
Dissonema turrida Mayer, : 00°, p. 44, pl. 2, figs. 3,4; :04, p. 8, pl. 2, fig. 70.
Plate 7, fig. 2; Plate 40, fig. 6; Plate 43, fig. 3; Plate 44, figs. 3, 4.

Acapulco Harbor; surface; 4 specimens, the largest being 4 mm. in
diameter.

Fortunately the specimens of this interesting species illustrate several
stages in the development of the gonads and show conclusively that they
belong primarily to the walls of the manubrium as already stated (p. 199),
and that their later outgrowth over the subumbrella surface is secondary.

The general form has been well represented by Mayer (: 00°); the apical
projection is high and stiff, the bell walls very thin. The largest specimen
measures 3 mm. in diameter.

Tentacles. —The two main tentacles are very stout, and rather longer
than the extreme height of the bell. The conformation of the rudimentary
tentacles separates this species very definitely from A. australis. The two
radial ones are of considerable size and length. Between the radial canals
in each quadrant there are three rudimentary tentacles (PI. 43, fig. 3), which,
according to the state of contraction, or possibly in part to individual varia-
tion, are either mere bulbs, or are prolonged into short filaments, as Mayer
figures them (:00°). I have observed both conditions in a single quadrant
of one specimen, Thus there are sixteen tentacular structures in all. On
the base of each of these, on its outer surface, there is an ectodermic ocellus
(Pl. 43, fig. 3).

The gonads of this species are its most interesting feature. In adult
specimens these structures appear, at first sight, to lie on the subumbrella
along the radial canals, as Mayer has represented them. It was this suppo-
sition which led him to include this species in the anthomedusan genus Dis-
sonema. Dissection shows, however, that in reality they likewise occupy the
walls of the manubrium. A study of the youngest medusa shows that they

originate on the manubrium, where they form eight thickenings (PI. 44,

STOMOTOCA. 201

fig. 3). These, in surface view, appear to be discontinuous in both per- and
interradii, but on sections it is seen that near the base of the manubrium the
gonad tissue is continuous across the interradial areas (Pl. 44, fig. 4). At
this stage, then, the gonads, being horseshoe-shaped, correspond to those of
Pandea and Tiara. They already show definite transverse folds; and in the
adults (Pl. 40, fig. 6) these folds are very prominent. The further growth
of the gonad is difficult to follow on the few available specimens. Apparently
the arms of each horseshoe become attached to the subumbrella surface along
the sides of the radial canals, thus forming subdivisions of the bell cavity
comparable to those in various Tiaridae; but in the present case the division
is apparently caused by outgrowths of the walls of the manubrium, and not
by dilations of the radial canals such as Vanhoffen (’89) has shown to be the
true nature of the “ mesenteries”’ described by Haeckel (’79).

Color. — In life (Pl. 40, fig. 6) the manubrium, gonads, and two primary
tentacles are salmon red, each of the latter with a deeper band along its
inner surface. The ocelli are claret red.

So far as I have been able to learn, the only other species of Amphi-
nemidae in which a type of gonad similar to that in A. furrida has been
described is the A. ocfaedrus of Haeckel, though the same condition occurs,
according to Brooks (: 03), in the genus Dichotomia. Unfortunately Haeckel
has not figured A. ocfaedrus, but as far as one can determine from his very
brief description it is certainly very closely allied to A. turrida, from which
it is separated by the octohedral form of the bell, and the smaller number
(ten) of rudimentary tentacles all of which are apparently of one size. It is
very desirable that this species be studied afresh. Meanwhile it seems best
to retain both A. octaedrus and A. turrida as distinct species in spite of their
close resemblance to each other. A. ¢urrida has been recorded only from
the West Indian region, A. octaedrus from the European coast.

Stomotoca L. Agassiz, 1862.

Amphinemidae with the stomach situated on a gelatinous peduncle.

Besides having a peduncle, S. atra A. Agassiz, S. pterophylia Haeckel,
and §. divisa Maas are distinguished from the various species of Amphi-
nema by having a much larger number of tentacles. The distinctions be-
tween the three species are slight. Maas (97) himself recognizes the close

relationship between S. pterophylla and S. divisa, but believes a new species

202 THE MEDUSAE.

necessary for the Panamic form, because of three features,—the presence of
an attenuated apical projection, the fact that the gelatinous dome of the dise

is divided by a coronal furrow, and because the tentacles are swollenbasally

so as to form distinct bulbs, which is not the case, according to Haeckel’s -

figure (79, taf. 4, fig. 20), in the West Indian S. pterophylla. Fortunately, I
have been able to test these three characters in a considerable series of Sto-
motoca in the present collection, from near the type locality of S. divisa, and
with the following results: — the presence of an apical projection proves to
be a character belonging to an immature state of development, and not one
diagnostic of the species; for while it is present and more or less prominent
in small specimens, 15-20 mm. in diameter, it is entirely absent in the largest
specimens, which, not only from their size but also from the condition of the
gonads, are evidently further advanced than any examined by Maas. The
coronal furrow is present in some specimens (though in none very marked),
absent in others, apparently irrespective of stages in development, — a varia-
tion showing beyond question that the furrow is not in any way comparable,
with reference to constancy or systematic importance, to the coronal furrow
of the Coronata. None of the present specimens show such an extreme de-
velopment of the tentacular bases as Maas (’97, taf. 1, fig. 3) has figured, yet
on the other hand there is always a definite thickening, so that in this re-
spect they stand intermediate between the accounts of Maas and Haeckel.
Inasmuch as the latter author drew his description solely from alcoholic
specimens it is a question how much stress to lay on this slight difference ;
for tentacles and even their bulbs often contract greatly, and even become
entirely distorted after preservation in alcohol. It is most unfortunate that
Haeckel could give no account of the color in S. pterophylla, for from compari-
son with 8. afrait appears that this character may be of specific importance in
this genus. From the above facts it appears that the resemblance between
S. pterophyllaand S. divisa is so close that it is doubtful whether the separation
of the two species is sound; but since it is impossible to answer this ques-
tion definitely without a fresh study of West Indian specimens of S. ptero-
phylla, and since there is a possibility that the slight difference in the form
of the basal bulbs of the tentacles, and the occasional occurrence of a coronal
furrow in the Panamie form, may prove to distinguish it from S. pterophylla, it
seems to me better to retain both names.

S. atra, though closely allied to S. plerophylla and S. divisa, seems to be

characterized by a much darker coloration than that of the West Indian or

STOMOTOCA DIVISA. 203

the Panamic species, the ovaries in S. atra being dark brown or blackish
(Agassiz, 65, p. 169), while in S. divsa they are pinkish; and by the fact,
which I have been able to corroborate on the original specimens now in the
collection of the Museum of Comparative Zoélogy, that there are fewer rudi-
mentary tentacles, the maximum observed being forty in S. atra as against
about one hundred and twenty in S. divisa.

Stomotoca divisa Maas.

Stomotoca divisa Maas, ’97, p. 11, taf. 1, figs. 7-9.

Plate 7, fig. 9; Plate 43, figs. 6, 7.

Station 4600; surface, October 15; many specimens, 8 mm. to 12 mm.

in diameter.
Station 4644; surface, November 7; 15 specimens, up to 25 mm. in

diameter.

The specimens in the first capture were all rather small; but when the
species was taken again, three weeks later, all but one were much more
advanced, the largest measuring about 25 mm, in diameter.

The gonads present a very interesting condition. In the smaller speci-
mens the condition is very similar to that described by Maas (97). As he
states, the gonads are continuous interradially at the base of the manubrium,
though so deeply cleft in the interradii as to be horseshoe-shaped ; the arms
of the horseshoe, lying on either side of the perradii, are complexly folded.
This is essentially the same condition as in Tiara and other Tiaridae, in all of
which the gonads are primarily interradial. So far as I know, no student
has demonstrated that the gonads in any Tiaridae or Amphinemidae are ever
entirely subdivided in the interradii. It is therefore of great interest to find
that such is their final state in the largest specimens of S. divisa; and I
believe that the number of specimens (fourteen) in which I have found this
extreme type is sufficient to establish it as the normal adult condition. There
is no doubt, however, from the conditions in younger specimens, that the
gonads are primarily interradial; and it is to be noted that in their final
condition they are not in any sense radial, since they always remain entirely
separated in the perradii. The complete separation of the two arms of each

horseshoe-shaped gonad is probably the result of rapid growth on the part

204 THE MEDUSAE.

of the walls of the manubrium, and is merely the end-stage in the process
by which simple interradial gonads are transformed into horseshoe-shaped
structures.

The folding of the gonads is complex, yet more regular and consider-
ably more pronounced than Maas has represented it. A typical example is
represented in Plate 43, figure 6.

I have already called attention to the fact that the tentacular bases
in the present series (Pl. 43, fig. 7) are less swollen than Maas (97) repre-
sents them. The number of rudimentary tentacles is important, inasmuch
as it may prove to be of some taxonomic value. In the largest speci-
mens there are from twenty-five to thirty of these per quadrant, 7. e. from
one hundred to one hundred and thirty on the entire margin. In life the
lips are long, and folded in an extremely complex manner.

Color. —In life the gonads vary from orange to brownish red; manu-
brium, lips, and radial canals pale lemon yellow ; tentacles yellowish. Since
the present specimens agree closely in this respect with those described by
Maas (’97) from notes and sketches made from life by Mr. A. Agassiz, it
appears that the coloration of this species is fairly constant.

One of the two localities at which S. diz’sa was taken, Station 4644, is
near the type locality, being just south of the Galapagos Islands. The
other locality is close to the Mexican coast, southeast of Acapulco. In the
Atlantic, S. pterophylla is recorded from the West Indies, between Cuba and
the Bahama Islands (Haeckel, ’79), and Dr. A. G. Mayer informs me that

he has since taken it himself in the West Indies.

Tiaridae Haeckel, 1879.
sens. em. Vanhoffen (’89).

Anthomedusae with gonads primarily interradial, though this location
may be masked secondarily by growth; with from four to many hollow ten-
tacles; radial canals broad, basally dilated, secondarily uniting with the
manubrium, thus forming the so-called mesenteries.

The following genera of Tiaridae seem sufficiently well established : —
Turris, Conis, Tiara, Pandea, Catablema, and Tiarocodon Browne (: 02).
Vanhiffen (89), it is true, has argued that Pandea, Turris, and Tiara should
all be united, the differences between them in the form of the gonads being

at most gradual, if not largely due to different stages in development; but

PANDEA VIOLACEA. 205

J agree with Hartlaub (92) and Maas (: 04°) that the conformation of the
sexual organs is sufficiently divergent in these three to warrant their reten-
tion as separate genera. ‘To express the confusion which reigns within
these genera I cannot do better than quote the following words of Maas : —
“il est impossible de déméler dans l’état présent de nos connaissances les
espéeces différentes décrites sous les synonymes divers (Oceania incl.) et, cer-
tainement en plusieurs cas, la méme espece se trouve cataloguée dans des
genres différents”’ (: 04°, p. 12). The present collection contains specimens
referable to Pandea, Tiara, and Turris, the latter apparently representing

a new species.

Pandea Lesson, 1837.
sens. em. Haeckel (’79).

Tiaridae with horseshoe-shaped gonads, not transversely folded, and

only slightly interrupted in the perradi.

Pandea violacea Agassiz and Mayer.

Pandea violacea Agassiz and Mayer, ’99, p. 160; Mayer, : 00°, p. 34, pl. 1, fig. 7.
Plate 41, figs. 10, 11.

Acapulco Harbor; surface; 7 specimens, all about 4 mm. in diameter
by 4 mm, high.

These specimens differ from the Fiji examples described by Agassiz and
Mayer (99) and those from the Tortugas described by Mayer (: 00") in
having a smaller number of rudimentary tentacles. In each there are eight
well-developed tentacles, extensible toalength greater than the height of the
bell (Mayer, : 00°, p. 34), though usually strongly contracted. In addition, the
present specimens have only eight rudimentary tentacles, alternating with
the well-developed ones, while in Mayer’s specimens there were twenty-four
of these. This difference appears, however, to be one of development, not of
species, since in the regular course of the formation of additional rudimentary
tentacles the next stage would be that found by Mayer. Mayer merely says
of the gonads that they distend the proximal part of the manubrium; and
inasmuch as he figures them as simple ovate perradial swellings it seems that
he overlooked their essentially interradial nature ; this can be clearly traced
in the present specimens, for though at first sight the gonads look like radial

structures, closer examination shows that there is no break in the formation

206 THE MEDUSAE.

of sexual products in the interradii, although in these planes they are re-
stricted to the basal end of the manubrium. The gonads, as Maas (: 04°) has
pointed out, are horseshoe-shaped structures, their arms lying along the side
of the radial canals. I have been unable to determine whether there is any
interruption in the perradii; and it is probable that there is not, but that in
P. violacea, as in P. conica (Maas, : 04°) the four primary gonads form a
practically continuous ring surrounding the manubrium. The surface of the
gonads is smooth, without transverse folds.

The manubrium is shorter and broader, and the mouth broader than
Mayer has figured them (: 00°, pl. 1, fig. 7), but the difference is no greater
than can readily be explained as due to different states of contraction or to
the preservation of the Acapulco specimens. There is no peduncle. The
mouth is surrounded by four simple lips. There is an ocellus at the base of
each developed or rudimentary tentacle (Pl. 41, fig. 10, 0).

Color. — The ocelli were vandyke brown in life; the gonads opaque,
slightly pinkish. Mayer observed a green streak running along the outer
surface of the endodermal lining of each radial canal, but this was absent
in the present specimens.

The chief difference between Pandea violacea and the well-known P.
conica of the Atlantic is that the former entirely lacks the exumbral nemato-
cyst ribs which appear to be specifically characteristic of the latter.

>

Tiara Lesson, 1837.
sens. em. Hartlaub (’92).

Tiaridae with horseshoe-shaped interradial gonads, their concavities di-
rected distally, their arms transversely folded. Tentacles in one series ; radial
canals with only small glandular evaginations, if any ; lips complexly folded.

To the above definition, which is essentially that of Hartlaub (92),
Maas has added : — “ Tentakel in regelmiissiger Weise auf die 4-Zahl zuriick-
fiihrbar” (:05, p. 14). This statement is no doubt true in general; but
inasmuch as I have found a variation from it in two of the four specimens
of the genus in the present collection, I hesitate to adopt it as one of the
distinctive characteristics of the genus. The present series agrees well with
Maas’s account of the “Siboga”’ specimens, which he refers to 7. papua
Lesson. This identification cannot be made positive, on account of the un-

satisfactory nature of the older illustrations of 7. papua; but so far as one

TIARA PAPUA. 207

can judge from them, it has strong probability of correctness, and as, from
the nature of these figures it is unlikely that any more satisfactory identi-
fication can ever be made, it will add to stability of nomenclature if it be
adopted.

Ihave no doubt that 7. oceanica Agassiz and Mayer (: 02) is merely a
more advanced stage of the same species, its larger number of tentacles
being easily explicable as a concomitant of growth, and the small size of
the single specimen seeming of but little significance in view of the ex-
treme variability of this character. Moreover Dr. Mayer has recently
informed me that he now believes 7’. oceanica to be identical with 7. papua if
not with 7. pileata. The same is true also, according to my view, of 7. inter-
media Browne (: 02) from the Falkland Islands, a conclusion already reached
by Maas (: 05). Browne has described the rudimentary tentacles of 7’. inter-
media as mere bulbs; whereas in the “Siboga” specimens they are true
tentacles, though small. These two states, however, are shown by the con-
ditions in the present series to be successive stages in development, the
bulbular preceding the tentacular; therefore they afford no ground for
specific separation.

The relationship of the Indo-Pacific species, 7. papua, to the common At-
lantic 7’ pileata cannot be decided at present. As Maas (: 05) has pointed
out, it is possible, especially since 7. papua has been recorded from the South
Atlantic (7. intermedia Browne) that the two may grade into each other; but
from the evidence now available it does not seem to me that such is likely
to be the case, for, so far as is known, adult 7. pileata always has a very
much larger number of tentacles than has ever been recorded for 7. papua.

T. suberba Mayer, from the Tortugas, appears to be a sufficiently well-
characterized species,

Tiara papua Lesson.

Turris papua Lesson, ’37, no. 36; '43, p. 283; Eydoux et Souleyet, 52, p. 639, pl. 2, figs. 1-3.
Tiara papua Maas, : 05, p. 14, taf. 2, fig. 13.

Tiara oceanica Agassiz and Mayer, : 02, p. 141, pl. 1, fig. 2.

Tiara intermedia Browne, : 02, p. 277.

Pl. 42, figs. 1 to 4.
Station 4605; 300 fathoms to surface; 1 specimen, 5 mm. in diameter.

Station 4652; 200 fathoms to surface; 1 specimen, 7 mm. high by

5 mm. in diameter.

208 THE MEDUSAE.

Station 4694; surface; 2 specimens, one 6X5 mm., the other very
immature, 3 X 2 mm.

The number of tentacles in the different specimens is as follows: — 5 mm.
in diameter, sixteen tentacles, eight large (radial and interradial), eight
rudimentary, bulbular (Pl. 42, fig. 3); 7X 5 mm., twenty, of which nine
large and eleven bulbular (Pl. 42, fig. 4); 6 X 5 mm., seventeen, nine large
and eight small, of the latter several tentacular, others bulbular; 3 X 2mm.,
eight, four large and four bulbular. ‘The maximum observed both by Browne
(: 02) and by Maas (: 05) was sixteen, eight large and eight small; Agassiz
and Mayer (: 02), however, have recorded a stage with thirty-two, eight
long, eight short, and sixteen bulbular. There is an ectodermic ocellus at
the base of every tentacle, and, as a rule, of every bulb; but in one speci-
men these structures were lacking in several of the bulbs, and in the
youngest specimen they are present on the four large tentacles only.
Absence of ocelli on a bulb is therefore evidence of the recent origin of
the latter.

In one specimen, Station 4605, diameter 5 mm., the radial canals are
somewhat jagged along their edges in their middle regions as they are de-
scribed by Maas (: 05) and by Agassiz and Mayer (:02). In all the remain-
ing specimens the canals are smooth.

The smallest specimen is of especial interest as being the youngest
individual of the species yet recorded. In outline (Pl. 42, fig. 7) it differs
markedly from older specimens, the apical projection, which in the latter is
low and triangular, being long and rodlike, with a well-marked apical canal
running its entire length and terminating in a dilatation. The manubrium
is very short; the lips as yet simple, though folded; there are no traces of
gonads. Tentacles eight, four large radial, four bulbular interradial. Ocelli
present on the four large radial tentacles only.

Color. — In life the manubrium, gonads, and tentacles are pink violet;
the ocelli are brownish red,

Tiara papua has been recorded under its various names from New Guinea
(Lesson) ; the Indian Ocean (Hydoux et Souleyet); the Malaysian region
(Maas); near the Marquesas Islands (Agassiz and Mayer) ; Falkland Islands
(Browne). The present captures are from the Humboldt Current off the
west coast of Central America and from the neighborhood of Easter Island.

TURRIS FONTATA. 209

Turris Lesson, 1837.
sens. em. Hartlaub (’92); Maas (: 04°).

Tiaridae with complex gonads, each consisting of two adradial series of
regular transverse folds which are often bifurcate ; connected with one an-
other near the base of the manubrium by a series of irregular thickenings,
and throughout the interradii by a network; radial canals with large
glandular diverticulae.

To the above diagnosis Maas (: 04°) has added the statement that new
tentacles are interpolated in a fashion different from the course of devel-
opment in Tiara, but he gives no description of the process. Another
feature which may prove distinctive is the fact that in Turris the glandular
diverticulae of the radial canals are much more highly developed, and more
complex than they have been described in any species of Tiara. Indeed,
they may closely resemble the condition figured by Maas (: 04°, pl. 2, fig.
10) for Catablema vesicaria A. Agassiz. Turris is easily distinguishable from
Catablema by the form of the gonads.

The present collection contains a single specimen of Turris. On general
principles I am strongly averse to basing a new species on one specimen ;
but in the present case it is justified, inasmuch as the specimen in question
differs in several important particulars from either of the two known
Pacific species, 7. pelagica Agassiz and Mayer (:02), and 7. brevicornis
Murbach and Shearer (: 03), as well as from the Atlantic species. It is
especially interesting from the possession of ectodermic pits apparently of
a sensory nature.

Turris fontata, sp. nov.
Plate 39, fig. 8; Plate 42, figs. 5-11.

Station 4576; surface; 1 specimen in excellent condition.

The single specimen is 22 mm. high; and the complexity of the gonads
and great size of the ova make probable that it is close to maturity. The
bell is 6f the outline usual in the genus, being high; with a low rounded
apical projection; gelatinous substance thin.

Tentacles. — There are sixteen large, five intermediate, and about forty
very small tentacles. The latter show all gradations from mere knobs
to tentacles with developed filaments (Pl. 42, fig. 6), and the interme-

diate tentacles connect them with the fully developed stage. The large
4

210 THE MEDUSAE.

tentacles arise from large basal bulbs which are laterally compressed (Pl. 42,
figs. 6, 11), and bear distinct spurs which curve over the exumbrella surface
of the bell margin (Pl. 42, fig. 12). On the outer surface of each bulb is an
opening connecting the cavity of the tentacle with the exterior (PI. 42, fig.
11 os.). At first I thought that these openings were accidental tears or
punctures; but finding that they occurred on all the large tentacles, I pre-
pared several series of longitudinal sections of tentacular bulbs, the study
of which has convinced me that they are perfectly normal structures. Such
a section (Pl. 42, fig. 7) shows that at the margin of the opening the
ectoderm and endoderm are continuous, so that it does not present at all
the appearance of an accidental tear. So far as I can learn, such ostia have
not previously been described,

Ocelli, —It is questionable whether the pigment spots in this species
can fairly be called ocelli, since they are clusters of separate granules
rather than discrete spots. They are present on the bases of the rudi-
mentary tentacles but absent from the large ones. In two tentacles of
intermediate size, in which very small openings have broken through in the
region of the spots, the pigment granules are scattered on either side of the
slit-like opening ; and it is possible that their absence from the large tenta-
cles is the result of such a scattering accompanying the further develop-
ment of the ostia. If this be true, then we might look forward to a stage
in which, with the growth of all the rudimentary into large tentacles, there
would be no pigment spots; but from the advanced condition of the speci-
men I think it improbable that such a growth of all the rudimentary tentacles
would take place.

Sense pits. —The ectodermal pits (Pl. 42, figs. 9, 10), to which, on account
of their resemblance to the sensory pits of many Acraspeda, I attribute a
sensory function, lie on the exumbrella surface, near the margin, usually one
just above the basal spur of each of the large tentacles (Pl. 42, fig. 6, s.).
Several tentacles, however, do not have them. Structurally they are simple
pits, lined with ectodermic bristle cells (Pl. 42, fig. 10). I have not been able
to find any similar organs described in any other Craspedotae. In many
Acraspeda, however, as is well known, similar pits occur, on the exumbrella
near the bases of the rhopalia, an example being figured in the present
memoir for Poralia rufescens (P|. 18, figs. 4, 5).

The manubrium is long; the lips folded and crenulated in an extremely

complex manner. The radial canals bear glandular diverticulae throughout

TURRIS FONTATA. Zio

their length; these diverticulae (Pl. 42, fig. 5) may or may not be branched,
as Hartlaub (’92) has described them for 7’. coeca. The circular canal bears
no diverticulae, though its margin is somewhat jagged (Pl. 42, fig. 5). The
canals are very deep basally, their inner faces being connected in the per-
radii with the walls of the manubrium. It was this conformation of the
canals in various Tiaridae which was responsible for Haeckel’s description
of mesenteries; his interpretation was shown by Vanhiffen (91) and by
Hartlaub (’92) to be erroneous.

Gonads. — The gonads are typical of the genus. Each consists (Pl. 39,
fig. 8) of two adradial series of transverse folds, often subdivided into two
hree, oreven more minor folds; the two series are connected in the interradii,
throughout their length by a scattered development of ova, and at the base
of the manubrium by a series of irregular folds. In the perradii, the two
adjacent series of folds are closely in contact, but separated by a narrow zone
in which no ova are developed. They thus closely resemble, except for
rather greater complexity and irregularity, the description and figure given
by Hartlaub (792) of the sexual organs in the Mediterranean and Atlantic
T. cocea.

Color. — In life the gonads were deep orange ; manubrium and tentacles
pale ochre yellow; bell bluish, hyaline.

All members of the genus Turris are closely allied. 7”. fontata in general
closely resembles both of the Pacific species, T. pelagica and T. brevicornis, yet
is distinguishable by several characters. It differs from both in its greater
development of glandular diverticulae of the radial canals, and in the fact
that these are often branched, for though diverticulae are described for both
T. pelagica (Agassiz and Mayer, : 02) and 7°. brevicornis (Murbach and Shearer,
:03), in both they are short and simple. From both, moreover, it differs
in the marginal organs and in color. 7. pelagica and 7. brevicornis have
all the tentacles alike ; and although it is true that the present species might
perhaps arrive at such a condition, did its growth and that of the rudimen-
tary tentacles continue far enough, yet we have no right to assume that this
is the case in view of the advanced condition of its gonads. The presence
of pigment spots at the bases of the rudimentary tentacles, even if not of
distinct ocelli, is a further characteristic feature, although we must bear in
mind that did all the rudimentary bulbs develop into tentacles these pigment
spots would probably be lost. Furthermore, and most important, in no
other species of the genus have tentacular ostia or exumbral sense-pits

212 THE MEDUSAE.

—

been described. The nearest ally appears to be the Atlantic species 7". coeca,
of which Hartlaub (’92) has given an excellent account.

Bythotiaridae Maas, 1905.

sens. em.

In 1905 Maas described, from the collections of the “Siboga” expedi-
tion, the new genus Sibogita, for a single specimen of a new species related,
in tentacle structure, to the Tiaridae, but, like Bythotiara Guenther (: 03),
apparently having branched canals. In the present collection there are two
specimens which very closely resemble Sibogita in general form and struc-
ture of bell margin, gonads and manubrium, but which differ from the type
of that genus in the structure of the canals. These are not branched, but
in addition to the four radial canals there are eight blind adradial canals
extending from the margin centripetally almost to the apex of the bell.
Fortunately both specimens show this feature so clearly that it is easily
demonstrable by photography. Dr. Maas, on examination, pronounced these
specimens at least generically distinct from his Sibogita, and suggested that
they might be the adult of his provisional genus Heterotiara; but the dis-
covery, in the present collection, of adult specimens of the latter genus
resembling his original account of Heterotiara in all characters, except
those of growth, renders that solution improbable. It seemed to me so
unlikely that the close general resemblance between the present specimens
and Sibogita could be connected with generic difference that I was in doubt
as to what disposition to make of them when I received from the United
States National Museum a specimen which threw an entirely new light on
the question. This specimen, which is more advanced than those collected
by the “Albatross,” though less so than the single “ Siboga” specimen, seems
to show that the appearance which led Maas to conclude that the canals
are branched is not the primary one; but is secondarily induced by a union
of the blind canals with the four arms of the cruciform base of the manu-
brium by further centripetal growth. If the canals of Sibogita are not
primarily branched, we must either remove it from the Bythotiaridae or
modify Maas’s (: 05) diagnosis of that family. Of the two courses the latter
seems to me preferable, inasmuch as Sibogita so closely resembles both
Bythotiara Guenther and Heterotiara, in the permanently interradial loca-

tion of its gonads, the structure of the bell margin, the hollow tentacles, and

SIBOGITA SIMULANS. 213

the absence of tentacular bulbs, that there is good reason to believe that the
three genera form a natural association. Furthermore it may be pointed
out that it is unwise to lay much weight on the supposed branching of the
canals in Bythotiara, since there is a possibility of the same explanation
there as in Sibogita. Bythotiara, like Sibogita, was founded for a single
specimen, and, so far as I am aware, has not been recorded since. Dicho-
tomia Brooks and Netocertoides Mayer (: 00”) probably belong to this family,
although in the former the structure of the gonads more nearly resembles
that in Amphinema turrida and A. octaedra.

The closest relationship of the Bathytiaridae is undoubtedly with the
Tiaridae: but they are easily distinguished from that family by the greater
development of the manubrium, which, as in most Leptomedusae, is dis-
tinguishable into basal, gastric, and oral regions; by the structure of the
gonads, which are permanently interradial instead of having this primitive
location masked with growth as is the case in most Tiaridae ; by the struc-
ture of the bell margin; and by the fact that the tentacles have no distinct
bulbs or ocelli.

Sibogita Maas, 1905.
sens. em.

Bythotiaridae with four primary radial canals, and, in addition, with
twelve (or more) centripetal canals, which secondarily come to join the
cruciform hase of the stomach; gonads transversely folded; bell laterally
flattened.

Although the specimens are undoubtedly congeneric with Sibogita, I
question their specific identity with S. geometrica Maas, since the chief
difference between the two, order of development of canals and tentacles, is
probably not to be explained as caused by differences in growth. It is
unfortunate that the series of this genus so far examined have been so
small; and for that reason final decision is still uncertain; but on the
whole it seems best to institute a new species for the three “ Albatross”
specimens.

Sibogita simulans, sp. nov.
Plate 5, figs. 4, 5, Type; Plate 41, figs. 8, 9; Plate 43, figs. 7, 2

Station 4635; surface; 2 specimens.

Also one specimen, from the United States National Museum, collected

214 THE MEDUSAE.

by the “Albatross” in Behring Sea, at Station 3325, in 121 fathoms of
water.

Size.— Both the specimens in the present collection are of about the
same dimensions, measuring about 30 mm. in height by 22 mm. in greatest
diameter. One is perfect; in the other the manubrium is torn away.

The Behring Sea individual of about the same size is contracted, but is
further advanced, as is shown by the condition of the gonads.

The bell is high, the gelatinous substance thick at the apex, but without
apical projection. As in S. geometrica (Maas : 05) the bell in all three speci-
mens is laterally flattened so that one diameter is much greater than the
other (PI. 5, fig. 5).

The manubrium is barrel-shaped; readily separable into basal, gastric,
and labial portions (Pl. 43, fig. 7). It is about one third as long as the
bell cavity is deep. Its base is cruciform, an outline particularly pro-
nounced in the Behring Sea specimen (fig. 2), with its four arms passing
gradually into the four radial canals, as Maas has noted (: 05, p. 17).

Canal system.—In the two younger specimens there are, in addition to
the four radial canals, eight adradial blind canals which extend centripetally
from the ring canal almost to the base of the manubrium. Their blind ter-
minations are clearly visible in the photograph of an oral view (Pl. 5,
fig. 5). Owing to the excellent condition of both specimens this important
feature could be demonstrated beyond question. The adradial, like the

radial canals, have no diverticulae,

wae yf y nor are they branched. However,
one of the blind canals showed an
Ce irregularity in being connected with

the neighboring radial canal by a

p> transverse bridge.
In the older specimen, from
(S \ Behring Sea, the condition of the

canals more nearly suggests that
described by Maas (: 05). In place
of ending blindly, the adradial canals now connect with the four arms of the
cruciform basis of the manubrium (fig.2). They have increased in number to
twelve and are somewhat irregularly arranged. None of them are branched.
When taken in connection with the conditions in the younger specimens in
which the adradial canals end blindly, it is evident that the adult state results

SIBOGITA SIMULANS. 215

from a union of the blind canals with the manubrium caused by further
centripetal growth; this view is supported by the fact that all the adradial
canals are narrowest at the point of union with the stomach. There seems
no objection to this explanation ; for if the growth of the blind canals takes
place far enough they can do nothing except come into contact with the
manubrium; and in the case of one of the canals of one of the younger
specimens the growth requisite to cause such a union would be less than
.O mm.

In the “ Siboga” specimen of S. geometrica there were thirty-two canals;
of which sixteen of the smallest join the other canals, radial and adradial,
at varying heights, instead of reaching the base of the manubrium. Their
condition is probably the result of the centripetal growth of blind canals;
but whether this is the case cannot be determined except from study of
immature specimens.

Tentacles. — In each of the two young specimens there are twelve ten-
tacles, one opposite each of the canals, radial or blind. In the older speci-
men there are thirty, one opposite each of the sixteen canals; the others
arranged somewhat irregularly between the canals. In WS. geometrica, not-
withstanding the larger number of canals, there were only sixteen tenta-
cles. In structure the tentacles, which are hollow, long, flexible, and
tipped with nematocyst clusters (Pl. 41, fig. 9), agree closely with those of
S. geometrica. They have no basal bulbs (PI. 43, fig. 2), nor is there any pig-
ment in their bases. As in S. geometrica, they arise from the exumbrella
some little distance above the margin, —a feature seen also in Heterotiara.
Connected with the prolongation of the gelatinous substance of the exum-
brella beyond the level at which the tentacles arise is a slight lobing, alter-
nating with the tentacles (Pl. 43, fig. 2), and as this was seen in life as well
as in the preserved specimens it is probably a normal feature.

Gonads. — The four gonads are permanently interradial, and, as in
Heterotiara (p. 217), entirely discontinuous in the perradii. They are con-
fined to the walls of the manubrium, and each, as already described by
Maas (: 05"), consists of a double series of regular transverse folds (Pl. 43,
fig. 1). In the Behring Sea specimen they are very large.

Color.—In life the gonads were reddish brown, the bell faintly tinged
with blue.

The capture of the two Eastern Tropical Pacific specimens on the surface

shows that this genus is not so purely intermediate as Maas (: 05) supposed.

216 THE MEDUSAE.

Unfortunately the label on the Behring Sea specimen gives no information
as to the depth from which it was taken, but at the station where it was
captured the depth is only 121 fathoms. If the surface is its usual habitat,
and its occurrence there not merely sporadic, its horizontal range is remark-
able in extending from tropical to cold waters.

Heterotiara Maas, 1905.
sens. em.

Bythotiaridae with four simple radial canals; with only short blind
canals if any; gonads purely interradial, without tranverse folds.

The collection contains two specimens which agree very closely with the
provisional genus Heterotiara proposed by Maas (:05) to include a single

’

immature specimen in the “Siboga” collection. In this specimen the four
canals were unbranched; but Maas has suggested that inasmuch as the
gonads were but slightly developed, branching might later appear. Since
the present specimens, both of which are sexually mature, have unbranched
canals, it is evident that in Heterotiara the simple condition of these struc-
tures is permanent. Neither are there any blind centripetal canals, such as
are developed in Sibogita.

The true specific relationship between the present and the “Siboga”
specimens is hard to determine, because of the immaturity of the latter ;
but inasmuch as the differences between the two appears no greater than
can be readily accounted for as due either to individual variation, or to dif-
ferences in the stages of growth, I include the present specimens under
Maas’s species H. anonyma.

Heterotiara anonyma Maas.

Heterotiara anonyma Maas, :05, p. 19, taf. 3, figs. 19-21.
Plate 41, figs. 12, 13.

Station 4650 ; 300 fathoms to surface ; 1 specimen.

Station 4652; 400 fathoms to surface ; 1 specimen.

The two specimens are of about the same size, 22 mm. high by 20 mm.
broad, and both are in fair condition. As in the “Siboga” specimen the
bell is high, the gelatinous substance thick at the apex; but there is no
apical projection.

Tentacles. —In one specimen there are eleven tentacles, in the other

HETEROTIARA ANONYMA. Zilyn

twelve (Pl. 41, fig. 12), four radial and eight adradial. In the « Siboga”
specimen Maas (: 05) records eight tentacles, four radial and four interradial ;
but as he had only a single specimen it is by no means safe to assume that
eight was the final number. On the contrary, in view of the variation in
number in the two specimens in the present collection it is probable that
with further growth more tentacles would have been formed. The tentacles
are long (not broken off as Maas found them), hollow, and flexible. There
are no distinct basal bulbs.

As in Sibogita, the gelatinous substance of the bell margin extends out-
ward and partially encloses the tentacle bases; a similar condition is de-
scribed and figured by Maas (: 05°) for Heterotiara. Maas has mentioned
endodermic pigment at the bases of the tentacles; but none was to be dis-
tinguished in the “ Albatross” specimens, perhaps on account of their con-
dition or preservation.

Manubrium.— The manubrium, as noted by Maas, is very different from
that of Tiara and more nearly resembles the condition in the Leptomedusae.
In both specimens it is barrel-shaped ; in one hanging to the bell opening, in
the other contracted ; it is seated directly on the subumbrella surface, with-
out peduncle. The mouth is quadrate and surrounded by simple lips.

The vascular system consists of four broad unbranched radial canals,
and of the ring canal. In one specimen there appears to be a rudimentary
triangular centripetal canal, such as is described by Maas (: 05, p. 19, taf. 3,
fig. 20), opposite one of the adradial tentacles; but the condition of the
margin is such that it is impossible to make certain whether this structure
is really a canal or not.

Gonads. —The permanently interradial location of the gonads is one
of the strongest reasons for classing this genus in the Bythotiaridae in
spite of the simplicity of the canal system. They are entirely discontinu-
ous in the perradii and limited entirely to the manubrium. They have no
definite transverse folds, such as are characteristic of Sibogita. Both
specimens are females, with ova so large that they are visible even to the
unassisted eye.

Color. —In both specimens the gonads were opaque yellowish; other-
wise they were colorless.

The main differences between the “ Albatross” and the “ Siboga” speci-
mens, apart from the more advanced condition of the gonads in the former,

are that the former have eleven or twelve tentacles, the latter only eight,

218 THE MEDUSAE.

and that the latter are considerably the larger. The number of tentacles,
when differing so little, as pointed out above, cannot be made the basis of
specific separation on the scanty evidence afforded by only four specimens;
and size, except when proved to be constant in large series, is even more
unreliable, being a character subject to great variation in Medusae. As
an example of its variability I need only refer to the well-known case of
Cyanea arctica.

The present captures, from between 300 and 400 fathoms and the sur-

’

face, and that of the “Siboga” specimen from between about 475 fathoms
and the surface, show that Heterotiara is an intermediate form. Its hori-
zontal range is extended by the “ Albatross” from the Malay Archipelago

to the Humboldt Current.

Williidae Forbes, 1848.
sens. em. Browne (’96, : 04).
Hydrolaridae Allman, 1872.

Anthomedusae with either four or six branched radial canals; tentacles
solid ; manubrium highly developed, separable into basal, gastric, and oral
portions, as among Leptomedusae ; with exumbral nettle strands.

We owe to Browne (96) the knowledge of the hydroid of Willia
stella, and also the demonstration, from a study of sections, that the
gonads belong to the walls of the manubrium, not to the radial canals, and
that the family therefore belongs to the Anthomedusae, not to the Lepto-
medusae as Haeckel (’79) supposed. According to both Browne (: 04) and
Maas (: 05) two genera are to be distinguished in this family : — Willia with
six, Proboscidactyla with four, main radial canals. The present collection

contains examples of the latter only.

Proboscidactyla Brandt, 1838.
sens. em. Browne, : 04; Maas, : 05.

Williidae, with four main radial canals.

The specimens of this genus in the collection appear to represent the
sexual stage of the form described by Maas (:05) as P. /lavicirrata, var.
stolonifera, which is no doubt the P. species of Huxley, for which Browne
(:04) has proposed the name P. tropica. I cannot agree with Maas (: 05)
that this form is a variety of P. /lavicirrata Brandt, because the type of

PROBOSCIDACTYLA 219

branching of the radial canals in the two species is very different, as has
been already pointed out by Browne (: 04). In P. flavicirrata the final num-
ber of canals and tentacles is very great (up to seventy-two); on the other
hand, in the present series, in sexually mature specimens, the maximum is
nineteen, and Maas (: 05, p. 21) has recorded a maximum of eighteen or more
for the “Siboga” specimens. In both mode of branching and number of
radial canals they closely resemble P. ornata McCrady, the common repre-
sentative of the genus on the Atlantic coast of North America, of which the
P. gemmifera of Fewkes and of Mayer is beyond question merely the budding
stage. Maas, it is true, has maintained that a different location of the
medusa-bearing stolons separates Atlantic from Pacific species, they being
more proximal in the former, more distal in the latter, though in both occur-
ring either on stomach wall or canals; but this character is variable in P.
ornata, while in the Pacific variety Huxley (77) found them at the jist,
Maas (: 05) at the second, branching of the radial canals. It seems to me,
therefore, that this character is of much less systematic importance than
the mode of branching of the canals, which, though more or less variable,
follows two fundamentally different types in P. ornata and P. flavicirrata.

In studying the present series I was fortunate enough to have at hand
for comparison numerous specimens of P. ornata, and also one of A. Agassiz’s
(65) specimens of P. flavicirrata, which, in spite of its age, is still in fair con-
dition. The conclusion I have reached is that the present series is hardly
to be distinguished from P. ornata, except that the growth of the gonads
and the multiplication of the tentacles progresses rather further in the
Pacific than it normally does in the Atlantic species. I have been unable
to find a single characteristic, except that of budding, to separate it from
Maas’s variety P. stolonifera. In type of branching of the canals, number
of the tentacles, arrangement of the exumbral nettle ridges, form, and size
they are indistinguishable. I have, therefore, no hesitation in maintaining
that they both represent two stages in the life history of one form, which
is a variety of P. ornata, not of P. flavicirrata. It seems to me that the ques-
tion of geographic distribution has no force as an argument against this
conclusion, because, as Maas (: 05, p. 20) has pointed out, the occurrence of
budding practically puts this genus, like Cytaeis, in the same class with the
holoplanktonic forms in so far as its dispersal is concerned, and it is there-
fore in no way remarkable to find close allies in both the Atlantic and the
Pacific.

bo
bo
(=)

THE MEDUSAE.

Proboscidactyla ornata McCrady var. stolonifera Maas.

Willsia ornata McCrady, ’57, p. 149, pl. 9, figs. 9-17.

Willia ornata A. Agassiz, ’65, p. 177, figs. 174 a-279 ; Fewkes, ’82°, p. 299, figs. 22-24.
Willetta ornata Haeckel, ’79, p. 157.

Discannota dysdipleura Haeckel, ’79, p. 152.

Proboscydactyla ornata Browne, : 04, p. 726.

Proboscydactyla flavicirrata var. stolonifera Maas, : 05, p. 21, taf. 4, figs. 24-28.
Proboscydactyla tropica Browne, : 04, p. 727.

Willia occidentalis Fewkes, 789°, p. 109, pl. 5, fig. 3.

Proboscydactyla varians Browne : (4, p. 728, pl. 54, figs. 7, 2.

Plate 6, Figs. 1, 2; Plate 41, Figs. 1-7.

Acapulco Harbor; surface; many specimens, 2.5-5 mm, in diameter.

There has likewise been available for comparison a series of excellently
preserved specimens of P. ornata from Newport, R. I. Specimens from 2.5-3
mm. in diameter are indistinguishable from the Newport series, the extent —
of the gonads, and the number of canals and tentacles (12-16), as well as the
mode of branching of the canals being the same in both forms. So far as
I can learn sixteen is the normal limit to the number of canals and tentacles
in the Atlantic P. ornafa; many of the Acapulco specimens, however, have
seventeen, eighteen, or even nineteen tentacles, and the same is true,
according to Maas (: 05) of the “Siboga” specimens. And since these num-
bers were counted in the largest specimens (4.5 mm. in diameter) it is fair to
assume that this increase is normal for the Pacific race. Such an increase
would not be at all surprising as a variation in P. ornata, since exactly this
same type of variation has been described by Browne (97) for the European
Willia stellata; but I have been unable to find any evidence that it actually
occurs in P. ornata from the Atlantic.

The only other difference (except in size) between the present series
and P. ornata is afforded by the gonads. In Atlantic specimens the limit of
development of these organs appears to be a stage in which they have
extended from the gastric wall outward along the line of the radial canals
nearly to the first bifurcation of the latter. This stage, however, seen in P.
ornda var. stolonifera of about 3 mm., is not the final one in that form, for
with the further growth of the Medusa the sexual organs extend further,
until they not only reach the division of the canals, but even pass beyond
it, so that finally a portion of the gonad comes to lie in each of the four angles
formed by the branching of the canals (PI. 41, fig. 4).

GEOGRAPHICAL DISTRIBUTION. 221

The mode of branching of the canals agrees closely with that described
for P. ornata, the resemblance to McCrady’s figure being extremely close,
and it is the same as has been described by Maas (: 05). Each of the
four radial canals bifurcates about one-fourth of the distance from its
origin to the margin. This condition, with eight tentacles opposite the
eight canals, is seen in specimens in which gonads have not yet appeared.
The eight canals thus formed branch then again, the second bifurcation being
the locality where stolons occur in the specimens described by Maas (: 05).
This is the normal limit to the branching in the Atlantic P. ornate. But in
P. ornata var. stolonifera most of the larger specimens have the canals still
further subdivided, in the manner shown diagrammatically (Pl. 41, fig. 7).
This is a very different type of branching from that exhibited by P. flavi-
cirrata Brandt, from the northwest coast of North America, in which each
radial canal branches once dichotomously, each of the two resulting canals
sending off numerous lateral branches from one side only (Brandt, ’38; A.
Agassiz, 65).

Color. — In life the gonads and tentacle bases are usually pale green ; other
portions are colorless ; some specimens however are entirely without color.

Proboscydactyla ornata has been recorded only from the Atlantic coast of
North America, where its range is known to extend from the West Indies
to Cape Cod. The variety stolonifera was described by Maas from the
Malaysian region, and Huxley’s specimen was taken in the Louisiade Archi-
pelago. Together with the present captures these records show that it is
very generally distributed over the Tropical Pacific. In the colder regions
‘of the north Pacific its place is taken by the much larger P. flavicirrata.

GEOGRAPHICAL DISTRIBUTION.

The oceanic region traversed by the “ Albatross” in 1904-05 is of great
interest to the student of zoogeography, for two reasons. In the first
place, it is bounded on one side by the great Humboldt, or Chili-Peruvian,
Current; a current of much lower temperature than the adjacent regions,
and comparable in size, in volume, and in regularity of flow to the Gulf
Stream, to the Guinea, the Benguela, or to the Japanese Current. In the
second place, it is one of the largest uninterrupted oceanic areas on the
globe, so that here, if anywhere, we might expect to find the pelagic fauna
unaffected by the disturbing elements, such as vertical circulation of water,

222. THE MEDUSAE.

food supply, and the like, which are associated with every coast line, no
matter how abrupt it may be.

I cannot pass over without mention the extraordinary richness of the
Humboldt Current in pelagic life of all kinds ; a richness which has already
been noted in the account of the general oceanographic features of the
Eastern Tropical Pacific by its leader, who speaks of “such masses of Sal-
pae, of Cytaeis, or Cymbulia, or swarms of other pelagic animals as to
make a thick soup” (A. Agassiz, : 06, p. 15), and of enormous quantities of
copepods, schizopods, Doliolum, and Medusae. Nor can I omit to recall the
discovery, immediately to the west and southwest of the Current, of an
area as barren in all forms of life, bottom as well as pelagic, as the latter
is rich. Thus “ As soon as we ran outside of this [the Humboldt Current]
the character of the surface fauna changed ; it became less and less abun-
dant as we made our way to Easter Island, the western half of the line
from Callao becoming gradually barren” (A. Agassiz, : 06, p. 9). On enter-
ing the Current again from the barren area the reverse change was equally
striking. Thus, to quote further: —“The pelagic and intermediate fauna
from Easter Island to 12° south latitude was very poor, and the serial
temperatures show that we were outside and to the westward of the
great Humboldt current. But near the 12th degree of southern latitude
a sudden change took place; the pelagic and intermediate fauna became
quite abundant again and soon fully as rich as at any time in the Humboldt
current, There was also a marked change in the temperature of the water
as indicated by the serials, showing that from the 12th degree of southern
latitude to the Galapagos we were cutting across the western part of the
Humboldt current” (A. Agassiz, : 06, p. 9).

The surface holoplanktonic Medusae in their quantitative distribution
well illustrate the general conditions thus outlined. Several species of
this group were so regularly taken that the Expedition may be said to
have given a comprehensive survey of their occurrence in the region
traversed, and the captures of four of these, which may be taken as typical
of the group, Liriope letraphylla, Rhopalonema velatum, Aglaura hemistoma,
and Cylaeis vulgaris, are graphically indicated on the chart, Plate 47. All
of these species occurred on all the lines, both within the Current and in the
barren area, while all but Cytaeis vulgaris were likewise taken off the west
coast of Mexico, and in the Gulf of Panama. I should mention that the
small number of records on the passage from Manga Reva to Acapulco is due

GEOGRAPHICAL DISTRIBUTION. 223

to the fact, already mentioned by Agassiz (:06, p. x), that unfavorable
weather prevented making many hauls on this line. Though none of the
species was lacking in the barren area, yet all occurred more regularly in
the Current. The difference in mass of individuals of the various species,
taken within and outside the Current, was quite as striking in the case of
the Medusae as of other pelagic organisms. While within its sweep Liriope,
Rhopalonema, and Cytaeis occurred in swarms on several occasions, and while
the nets invariably yielded many specimens of other species of Medusae,
ctenophores, and siphonophores, to the westward of the Current but few
living Medusae were taken, the hauls containing, instead of perhaps several
hundred individuals, not more than five or ten specimens of living acalephs
of all kinds. On the other hand, in the barren area considerable numbers
of dead Medusae as well as dead animal detritus of other kinds were taken
(A. Agassiz, : 06).

This decrease, though most sudden along the zone indicated by the serial
temperatures as the margin of the Current, progressed steadily to the west-
ward, the region surrounding Easter Island being the poorest. Indeed in
this neighborhood several successive surface hauls yielded no Medusae at
all, something that did not happen elsewhere during the Expedition.

The intermediate Medusae show the same quantitative decrease from east
to west as do the surface species, but in much more extreme fashion. On
the chart, Plate 48, is represented the occurrence of six of the commoner
species : — Halicreas papillosum, Atolla wyvillei, Periphylla hyacinthina, Crossota
brunnea, Colobonema typicum, and Ptychogena erythrogonon. To these Nausithot
rubra, Homoenema alba, and Aeginura grimaldi might be added without
altering the general import. Although none of these intermediate species
were taken so regularly as were several of the surface forms, yet all,
except Ptychogena erythrogonon which was restricted to the neighborhood
of the Peruvian coast, occurred frequently on all our lines so long as we
were within the sweep of the Current, both in its north and south course
and in its westward extension; but, as is shown on the chart, there is no
record of a single individual of any of these species in the barren area to
the westward of the fairly well-defined outer limit of the Current. This
lack is especially striking in the case of Halicreas papillosum, inasmuch as
this species, in the regularity of its occurrence, occupies among the inter-
mediate forms the same position that Liriope tetraphylla and LRhopalonema
velatum do among the surface species. We have no right, however, to

99 THE MEDUSAE.

aa

assume that this disappearance is absolute, the evidence afforded by hauls
one hundred and fifty miles apart being far too scanty to warrant such
a conclusion. On the contrary, it is hardly conceivable that some or all
of these species do not occasionally occur in the barren area as does Tetror-
chis erythrogaster ; and even with this reservation, the difference in degree, if
not in kind, between the gradual east-west diminution of the surface forms,
and this sudden disappearance of the common intermediate species, is as
striking as it is unexpected.

The occurrence of the holoplanktonic surface Medusae is about what
might be expected in any oceanic region traversed by a well-marked ocean
current. Indeed a very similar diminution in number of individuals is con-
stantly to be seen on leaving the Gulf Stream; but to account for the
conditions which obtain in the distribution of the intermediate Medusae
is by no means easy.

I must confess that I have been unable to find any satisfactory expla-
nation for the apparent limit to their westward dispersal. This limit, I
might add, is more or less effective not only in the case of Medusae, but
of the bathypelagic fauna as a whole; for in all classes of organisms the
diminution, whether or not approaching total disappearance, was much
more sudden among the intermediate than among the surface forms. Fur-
thermore, comparison with chart 3° of the general report of the Expedition
(A. Agassiz, :06) shows that the line of disappearance of the interme-
diate Medusae coincides almost exactly with the line of southern limit
of good trawl hauls, so that it appears that, as might be expected, this
quantitative diminution is not limited to the pelagic fauna alone, but holds
true also for the bottom species, which depend ultimately upon the
pelagic fauna and flora for their food supply. Temperature, so frequently
a barrier to the dispersal of marine organisms, offers no satisfactory expla-
nation of the present case. For although the surface temperature showed
a very wide range from the coast westward, the extremes observed being
65° and 82°, below the depth to which the diurnal warming of the sun
may be expected to penetrate (say 50 fathoms), the temperatures were
remarkably uniform throughout the entire area traversed during the cruise.
Thus at 200 fathoms the extremes of temperature recorded are 56.7° and
48.5°, a range of 8.2°; at 300 fathoms, 48.2° and 42.7°, a range of 5.6°

(oy:

(omitting one record of 53.2°,due no doubt to some local disturbance) ; while

at 400 fathoms, with extremes of 42.5° and 41.9°, there was a range of

GEOGRAPHICAL DISTRIBUTION. 225

only .6° (A. Agassiz, :06, p. 24). Furthermore, even these slight varia-
tions were fluctuating, and not in any way connected with the line of faunal
diminution. Another factor which must be considered is salinity. But it
is unlikely that this is any more important than temperature in the present
connection ; for although the density decreases with the increase in surface
temperature from the South American coast westward, this decrease is
extremely gradual and without any sudden changes. And it is well known
that many Medusae, for example Aurelia and Gonionemus, can undergo much
greater fluctuations in salinity without suffering the slightest ill effects.

The question of food supply is no doubt effective in checking the
increase of intermediate organisms in the barren area; for the surface
fauna and flora are quantitatively much less abundant here than within the
Humboldt Current. But since the diminution in the food supply is gradual,
it cannot explain the much more sudden and extreme diminution of the
intermediate fauna. On the contrary, the abundance of dead animal and
plant detritus (belonging for the most part to surface forms) taken in the
intermediate nets far beyond the limit of abundance of the intermediate
fauna, compared with the absence of such material within the Current where
the latter is abundant, suggests in a striking way that it is not scarcity of
food that limits the effective barrier, but that the food supply outside the
Current is more than sufficient for the few intermediate organisms which
occur there.

It has been suggested to me that variations in the degree of oxygenation
of the sea-water might be a more important factor in the ecology of the in-
termediate fauna than has generally been supposed. Our actual knowledge
of the gaseous content of the deeper waters of truly oceanic areas is, on
account of the difficulty of working on shipboard, still so limited that the
suggestion may be worth consideration. On theoretic grounds it would seem
not unlikely that vertical circulation must be much more active in regions
where the water is in constant horizontal motion, on account of the much
greater disturbance of the surface layer caused by storms in such regions ;
and that such overturning must favor the absorption of oxygen in oceanic
regions just asit does in fresh-water rivers, It is most unlikely, however,
that the slight fluctuations which might thus be produced could influence the
distribution of Medusae when we consider what extensive changes in oxy-
genation several genera of Medusae undergo in their normal habitat.

One of the more important features of the collection is the support which

15

296 : THE MEDUSAE.

an

it affords to the theory, urged particularly by Chun and by Vanhiffen, of
the unity of the holoplanktonic fauna in the warmer regions of all oceans.
Thus, in part through new records and in part as the result of fresh identifi-
cation of long known forms made possible by better material, the ranges of
Rhopalonema velatum, Aglaura hemistoma, Liriope tetraphylla, Solmundella bitenta-
culata, Cunoctantha octonaria, and Evrene viridula are extended to the Eastern
Pacific; and since all of these were previously known from both the Atlantic
and the Indian oceans, their occurrence in the tropical regions of all oceans is
now demonstrated. Equally extended are the geographic ranges of Geryonia
proboscidalis, and probably of Pegantha triloba and Solmissus incisa, while Nau-
sithoé punctata, found in Arctic as well as temperate and tropical waters, is
even more widely dispersed. Solmissus marshalli may eventually prove to
belong to the Atlantic as well as to the Pacific when its specific relation-
ship to its close Mediterranean ally S. albescens is better understood. Pe-
gantha martagon is so far known only from the Pacific and Indian oceans
and from the China Sea; but it is not unlikely that its range may be fur-
ther extended. As to the ranges of the four new species of Narcomedusae,
which may naturally be expected to be widely dispersed, nothing can be
said as yet.

The ranges of the following intermediate forms are likewise extended
to the Pacific: — Periphyllopsis braueri, Aeginura grimaldii, Crossota brunnea,
Homoeonema alba, Halicreas papillosum, Colobonema sericeum, Rhopalonema fune-
rarium, and Nausithoé rubra. Atolla wyvillii has not previously been recorded
under this name from this region; but at least one of the Pacific records of
A. alexandri belong to this species (p. 39).

Many of the intermediate Medusae are much more widely distributed
than most of the surface forms, Periphylla, Crossota, and Homoeonema extend-
ing from the tropics to the Arctic (or Antarctic) regions in all oceans. This
phenomenon is no doubt correlated with the freedom of the intermediate
zone from the violent changes in temperature which limit the migration of
the great majority of surface animals. Thus the temperature range at 300
fathoms in all oceanic areas is much smaller than that occupied by certain
holoplanktonic surface Medusae, for example, Rhopalonema velatum and Liriope
letraphylla, both of which were found in temperatures of from 64° to 82° on
the present Expedition.

Although the tendency of modern study is to show that the great majority

GEOGRAPHICAL DISTRIBUTION. 227

of intermediate Medusae are practically universal in oceanic regions, yet there
is reason to believe that some few may be local, or even littoral. A case
in point is Ptychogena erythrogonon. ‘This species was taken only in a re-
stricted area off the coast of Peru, and although fairly common, never at
any great distance from the land. In all probability, judging from analogy
with its natural allies, the species passes through a hydroid stage; and if
this be the case it is probably the hydroid, not the medusa, which is the
factor limiting its dispersal.

Apart from the undoubted holoplanktonic forms but few species of Hydro-
medusae were taken during the oceanic portion of the cruise, the only species
which can be classed here, under the supposition that they pass through a
fixed hydroid stage, being Tiara papua, Aequorea macrodactylum, Aequorea
coerulescens, Hirene viridula, Purena browne, Gonionemus suvaensis, and Olindias
singularis. All of these were previously known from the Pacific or from the
Indian ocean, or from both; none however, except Lirene viridula, are as
yet known certainly from the Atlantic, although all are represented there by
close allies.

The collection made in Acapulco Harbor is most instructive on account of
the affinities of its members; for of the fifteen species previously known,
excluding the holoplanktonic genera Liriope, Aglaura, Solmundella, and
Cunoctantha, only seven were previously recorded from either the Pacific or
Indian oceans alone ; one, Proboscydactyla ornata, is known in its two varie-
ties from both Indian and Atlantic oceans; while no less than seven species,
Eetopleura ochracea, Phialidium discoida, Phialium duodecimalis, Amphinema
turrida, Amphinema australis, Lymnorca alexandri, and (probably) Zanclea gem-
mosa, are known from the Atlantic alone. Furthermore, all of these Atlantic
forms, with the possible exception of Ectoplewra ochracca, are, so far as we yet
know, limited to the western coast of the Atlantic south of Cape Cod. And
the same is true also of the Atlantic distribution of Proboscydactyla ornata;
while Stomotoca divisa, not taken in Acapulco Harbor itself but off the coast of
Mexico and in the Gulf of Panama, is so closely allied to the West Indian S.
pterophylla as to be hardly separable from it (p. 202). Up to the present
time our knowledge of the leptoline Medusa fauna of the tropical west coast
of America, north or south, has been almost ni; while the same is true
to-day of that of the east coast of Mexico, and of the north and northeast
coasts of South America.

Mayer has already called attention to a resemblance between the lepto-

228 THE MEDUSAE.

line fauna of the Fiji Islands and that of the Tortugas. In part his state-
ment requires revision, as the claim to similarity is largely based on
correspondence of genera; a correspondence mainly explicable on grounds
of the close agreement between the physical features of these two groups
of coral islands. But although the resemblance when analyzed proves to be
less close than Mayer supposed, the fact remains that there are found in the
Fiji Islands two species, Halitiara formosa and Pandea violacea, common in the
West Indies but known neither from the Indian Ocean nor from the Pacific,
until the capture of the latter species by the “ Albatross ” at Acapulco.

The affinity between the littoral faunae of the two sides of Central
America is much closer in the case of the Medusae, and probably of the
hydroids also (S. F. Clarke, ’94, :07), of which group several species occur
both in the Gulf of Panama and in the Carribean, than in the higher groups
of animals such as echinoderms and fishes, in which the parallelism, at first
supposed to be one of species, has since been shown to be chiefly one of
genera only (Verrill, 67; Agassiz, : 04; Jordan, : 08).

The facts of distribution disclosed by the “ Albatross” expedition of
1904-1905 suggest that the Pacific, so far as its littoral Medusa fauna is
concerned, is separable into two more or less clearly defined areas ; its west-
ern half being closely connected to, if indeed at all separable from, the
Malaysian region, a fact already known to be true for echinoderms, crusta-
ceans (Ortmann), and for stony corals (Verrill, Vaughan) ; and its eastern
shores on the other hand having a close affinity to the Gulf of Mexico and
to the Tropical Atlantic. It would appear that although these two areas
undoubtedly overlap, the broad oceanic belt separating the west coast of
America on the one hand from Polynesia and the Hawaiian Islands on the
other, has proved an effective barrier to the dispersal of many of the hydroid
Medusae.

Batnymetric Ranex.

The work of the recent deep-sea expeditions, American and European,
has demonstrated that a considerable series of Medusae, both craspedote
and acraspedote, undoubtedly belong to the intermediate depths. These
species are often termed “deep sea,” “ Tiefsee,”’ especially by the Ger-
man investigators; but since this term is ambiguous from its common
application to abyssal bottom animals, I prefer to adopt for such Medusae,
as well as for other organisms of similar bathymetric occurrence, the term
* intermediate.”

3ATHYMETRIC RANGE. 229

Although it is now generally admitted that, in spite of occasional records
of the sporadic appearance of such genera as Atolla and Periphylla on the
surface, they are not normally surface forms, the question at what par-
‘ticular zone they are most abundant, or whether they are indifferently dis-
tributed from top to bottom, or even live just above the bottom, as recently
suggested by Maas (:04°), has not as yet been answered conclusively.
In general two views have been held, though not, it is true, always
clearly defined : first, that they belong for the most part to abyssal depths,
as both Maas (: 04°, :05) and Vanhéffen (:02*) have in general main-
tained ; and secondly, that they reach their greatest abundance in the upper
layers, between the surface and a depth of about 300 fathoms. Discussions
of this question have, for the most part, been rather inadequate, due
largely to the use of the much-abused term “deep sea,” largely to differ-
ences of opinion as to what constitutes “great depths.” And inasmuch as
the location of the normal range of this group of organisms is of much
interest in the general ecology of the intermediate fauna, a re-examination
of the evidence, most of which unfortunately is indirect, is desirable.

In so far as concerns the occurrence of intermediate Medusae on the sur-
face, it is to be noted that although both Atolla and Periphylla have been
taken there, none of the recent exploring expeditions have captured any of
this group on the surface, with the exception of one fragmentary specimen
of Halicreas papillosum in the present collection, in spite of the great number
of surface hauls which have been made both by day and by night; on the
other hand, all recent expeditions have taken intermediate Medusae in con-
siderable numbers in vertical and intermediate hauls. Probably, then, the
occurrence of these genera at the surface is to be interpreted, not as an
indication of their normal habitat, but as the manifestation of some such
physical phenomenon as unusually violent vertical circulation of the water,
or a peculiar condition of oceanic temperatures.

The most important direct evidence to show the exact depth from which
individual specimens were taken is of course that afforded by closing-net
hauls. Unfortunately, however, the captures of Medusae in such hauls have
been comparatively few, the following being the only records which I have
been able to find: —on the “ Valdivia” expedition, so far as the results of
Vanhiffen’s researches are yet published, Medusae were taken but three
times in closing nets; namely, one specimen of Periphylla at 810-540 fath-
oms (1,500-1,000 meters), one specimen of Colobonema at 810-485 fathoms

230 . THE MEDUSAE.

—

(1,500-900 meters), and Rhopalonema velatum at 165-105 fathoms (300-200
meters). The following captures are recorded by Browne (: 06), from the
cruise of H. M.S. “ Research” in the Bay of Biscay : — Periphylla, 400-300
fathoms, and A/olla bairdii, 1,500-750 fathoms. In addition to these two
intermediate genera, one well-known surface form, Aglantha rosea, was also
taken in eight closing-net hauls, as follows: — 150-50 fathoms, seven speci-
mens; 200-100 fathoms, five specimens; 300-200 fathoms, one specimen ;
500-400 fathoms, two specimens; 750-500 fathoms, 1 specimen, 1,000-500
fathoms, 1 specimen; 1,250-1,000 fathoms, one specimen. This was the
commonest epiplanktonic species of the Expedition, and for this reason it is
probable, as Fowler (: 06, p. 183) has suggested, that the deeper captures
were merely dead specimens sinking to the bottom; the species, however,
was apparently alive down to 100 fathoms. A large number of closing-net

”

hauls have been made by the “ Princess Alice,” those containing Medusae
from known depths (Maas, : 04°) being 1,700 meters, Atolla and Agliscera ;
300-350 meters, Phialidium; 800 meters, Periphylla; 1,000 meters, Peri-
phylla; and 781 meters, Aeginura. During the “ Albatross” expedition of
1904-05 the following closing-net captures were made :—at Station 4668
Tanner net towed, at 300 fathoms, Halitrephes and Rhopalonema, the latter
too fragmentary for specific identification; Station 4672, Tanner net
towed, at 400 fathoms, Aeginura, Atolla, Crossota, Aegina. Both the Chun-
Petersen and Tanner nets were used on other occasions, but only in these
two hauls were Medusae taken.

When these various closing-net hauls are analyzed it appears that they
are not such strong evidence in favor of abyssal occurrence in truly
oceanic areas as might at first be supposed. Thus, two of the “ Princess
Alice” captures, those of Periphylla from 800 and 1,000 meters were
within the Mediterranean, an enclosed sea in which the temperature con-
ditions are very different from those of oceanic regions; and the deepest
haul, 1,700 meters (about 880 fathoms), was made only some fifty miles off
the coast of Spain. More strictly oceanic is the record of Aeginura, from
about 420 fathoms. Neither of the “ Valdivia” records are from very great
depths, and the greatest, Periphylla, from between 540 and 810 fathoms,
is based on a specimen so fragmentary that it is questionable whether it was
not dead and sinking at the time of capture. Both the “ Albatross” records,
one of which comprises the greatest number of different genera of Medusae
yet taken in one haul of a closing net, are from moderate depths (300 and

BATHYMETRIC RANGE. 231

400 fathoms). It is very desirable that more hauls be made with closing
nets adapted to the capture of large organisms, many of those now in use
being, as Apstein (: 06, p. 277) points out, unfitted for this purpose.

Next in value to closing-net hauls are serial hauls, based on the compara-
tive method, with open tow-nets; that is, hauls from different depths made
at one station at the same time or in immediate succession with nets of
the same diameter and size of mesh. This method, owing to the amount of
time necessary to carry it out, has seldom been used comprehensively. Far
the most important instance, in the present connection, is afforded by the
investigations of Murray (99) in the North Atlantic. Though none of the
typical intermediate Medusae were taken during this Expedition, Agdantha
digitale is recorded (Guenther, : 03, p. 427) as reaching its greatest abun-
dance at the very great depth of over 1,000 fathoms. But the fragmentary
condition of all the specimens (minus manubrium, gonads, tentacles), to-
gether with the season of the year (November) when the hauls were made,
strongly suggests that the captures are not to be taken as indicating the
normal occurrence of this surface form at such a depth, but rather that the
net encountered swarms of dead specimens in the process of sinking to
the bottom after the discharge of their sexual products.

The evidence afforded by captures made in ordinary open tow-nets from
considerable depths is much more extensive, but must be analyzed with even
greater discrimination than that of the closing nets. Especially must we
guard against any tendency to locate specimens from the lowest point of
vertical hauls, as has often been done in the past. Such a method is of
course entirely misleading; the actual evidence given by any one haul is no
more precise than that its contents came from somewhere between the lowest
point attained and the surface, Obviously the shorter the column of water
through which the net is towed the more accurately is the zone of origin of
its contents located. Conversely, when vertical hauls are made from near
the bottom to the surface they indicate merely that the contents came from
somewhere between the bottom and the top. Such hauls are often of great
value in obtaining material; they are of little (unless used in conjunction
with the comparative method already mentioned) in locating the level from
which the contained specimens were taken, And of course even less instruc-
tive, from this point of view, are sporadic records of captures of pelagic
animals in the trawl or dredge, unless such records are checked by some

other class of observations. The importance of this precaution seems to

232 THE MEDUSAE.

have been overlooked in much of the general discussion of the range of the
bathypelagic fauna.

The captures of intermediate Medusae recorded by the recent Euro-
pean deep-sea expeditions have been for the most part from comparatively
deep hauls, — usually from below 500 fathoms, and often from very much
greater depths. From less than 300 fathoms very few intermediate Me-
dusae are recorded either by the “ Valdivia” or “ Siboga” expeditions, or by
those of the “ Princess Alice.” It seems that this absence is to be explained
largely by the fact that on all these expeditions but few comparatively
shallow hauls, except from such trivial depths as 20 or 30 fathoms, were
made with nets of a type fitted for the capture of large organisms. In esti-
mating the value of such negative evidence it must be borne in mind that
the fine-meshed Plankton net, especially after being used a few times, is
admirably calculated to miss all large specimens when in use at the speed
of a steamer under way. We cannot, then, interpret the scarcity of records
from these expeditions of intermediate Medusae from the upper 300 fathoms
as indicating absence of these organisms in that zone. On the contrary,
there is good evidence that they not only occur, but are abundant between
300 fathoms and the surface. Thus the few captures of intermediate
Medusae in open nets on the “ Research” expedition are all from mode-
rate depths,—the records being, Colobonema from 250 fathoms to surface ;
Homoeonema platygonon, 100 fathoms to surface, 200 to surface, 250 to
surface, and 350 to surface; and of Periphylla, from 350 fathoms to the
surface (Browne, :06). And even more positive evidence to the same effect
is afforded by the present collection.

During the expeditions of the “Albatross,” particularly that of 1904-05,
the method of towing has been to make frequent hauls from 300 fathoms to
the surface, and occasional deeper hauls, which, together with the numerous
trawl hauls, might be expected to reveal pelagic organisms confined to the
region below 500 fathoms. The results from this method of collection were
particularly positive and instructive on the Expedition of 1904-05. During
this trip intermediate Medusae were taken in forty hauls at thirty-five sta-
tions, the depths being : —at twenty-three stations, 300 fathoms to surface ;
two stations, 400 fathoms to surface; one station, 600 fathoms to surface;
one station, 800 fathoms to surface; and at nine stations in the trawl.

A significant feature of the case is that in every instance in which a 300

fathom haul was made at the same station where intermediate Medusae

BATHYMETRIC RANGE. 233

were taken in the trawl, the same genus was taken in the vertical haul
as in the trawl,—a fact indicating of how little value a “trawl” record
is in locating these intermediate organisms; and a still more important
fact connected with these records is that not a single species was taken in
hauls from below 300 fathoms, which was not also taken in other hauls
between 300 fathoms and the surface, although the majority of the genera
of Medusae as yet known to belong to the intermediate fauna were taken
during the Expedition, and several of them in considerable abundance.

These positive results show beyond question that in the Eastern Tropical
Pacific the intermediate Medusae are by no means characteristic of abyssal
depths, but attain a high degree of development in the comparatively shal-
low zone between 300 fathoms and the surface,—a result already men-
tioned by the leader of the expedition for the intermediate fauna in general
(A. Agassiz, :06). Furthermore, considering how much more important
is this considerable body of positive results, which might be enlarged by
adding thereto the records uf the “Albatross” expedition of 1891 and the
shallow hauls of the “ Valdivia,” “Siboga,” and “Research” expeditions,
than any amount of negative evidence of the kind afforded by the contents
of open nets towed from abyssal depths to the surface at isolated stations,
and in view of the uniformity in physical conditions below the upper 50-
100 fathoms in all oceans, there is good reason to extend this generalization
to all tropical oceanic areas removed from the disturbing influence of neigh-
boring coast lines. The question of bathymetric range in such enclosed
seas as the Mediterranean is quite a different question, and one outside the
scope of the present discussion.

I do not, however, mean to imply that the intermediate fauna is re-
stricted to this zone. On the contrary, while I believe that there is good
evidence of the existence of a limit to its upward dispersal, there is appar-
ently no such barrier to its downward movement. ‘Therefore intermediate
organisms may be expected to occur, though according to my view in much
less abundance, even to near the ocean floor in very great depths.

With regard to the limit to their upward migration the questions of
light and temperature are, no doubt, of prime importance, most investigators
now agreeing that in the case of such organisms as Medusae pressure cannot
be supposed to be an active factor. While but few experiments have been
made upon the penetration of light in sea water, it is probably safe to assume
that the last of the sun’s rays are dissipated at about 500 meters, somewhat

234 THE MEDUSAE.

more than 250 fathoms; and that light below 100 fathoms must be very
faint indeed,—a result in entire accordance with the vertical range of
littoral Algae.

Since the intermediate Medusae do not normally come to the surface in
cold any more than in warm regions, it is probable that it is not the in-
crease in temperature, but light, which is the more important factor of the
two in limiting their dispersal. Whether, however, the region most favorable
for them is that of absolute darkness, or whether they, like some copepods,
are positively phototropic to light of faint intensity, while negatively so to
darkness on the one hand and brilliant light on the other, cannot be answered
until experiments have been made with this end in view. But in considera-
tion of the fact that captures in closing nets from greater depths than 300
fathoms have several times been recorded, I believe that the former sug-
gestion is the correct one, and that the normal upper limit to the vertical
range of these species will eventually be found to coincide approximately
with the lower limit to which the sun’s rays can penetrate with appreciable
strength. This, however, by no means indicates that their upper limit is
necessarily as deep as 250 fathoms. On the contrary, it is well known that
the penetration of light depends very largely on the clearness of the water ;
and in a region with such a rich fauna and flora as the Humboldt Current the
lower limit of appreciable light may be expected to lie at a much smaller
depth than in the clearer waters where it has been tested. Judging from
the fluctuations in the penetration of light, the upper limit of the intermedi-
ate Medusae probably differs greatly in different regions, being nearest the
surface in the courses of the densely inhabited ocean currents, and deeper in
regions where pelagic life is less dense and the water consequently clearer.

Besides the actual evidence afforded by the “ Albatross” captures, there
is strong theoretic ground, judging from the nature of their food supply, for
expecting this group of organisms to be most abundant near the upper limit
of their vertical range. In the last resort, sustenance, for the intermediate
fauna as well as for the abyssal bottom fauna, must be derived indirectly or
directly from the pelagic flora of the surface and of slight depths; interme-
diate as well as bottom animals must largely depend for their food on sinking
detritus. It would then be only natural to expect them to congregate and
multiply in greatest abundance in close proximity to this supply ; that is,
near or at the upper limit of their range. This consideration seems to me

of very great significance.

BATHYMETRIC RANGE. 230

The establishment of the upper limit of the normal vertical range of the
intermediate Medusae is of quite as much importance to the oceanographer
as to the zodlogist, since these organisms are among the most important
natural buoys to show the flow of oceanic currents. In the present case
their apparent absence or at least great rarity in the barren area west of
the Humboldt Current indicates that the general west or northwest move-
ment of the surface waters of that portion of the south-tropical eastern
Pacific within the trade-wind belt, correlated with the general southeasterly
direction of the trades, to which attention has already been called by Agassiz
(: 06), does not extend downward much below the upper limit of their range,
but is limited to a shallow surface zone, probably not extending below
about 200 fathoms. Otherwise the intermediate, like the surface Medusae,
would be dispersed from the Current throughout the barren area.

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Mixer, F., ’61°. Polypen und Quallen von Santa Catharina. Olindias Sambaquensis, n.
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Miter, F., 65. Uber die Randblaschen der Hydroidquallen (Aglauropsis). Arch. f.
Mikr. Anat., bd. 1, p. 143-147, taf. 7.

Mvetier, J., 51. Ueber eine Eigentiimliche Meduse des Mittelmeeres und ihren Jugend-
zustand. Arch. f. Anat. Physiol., jahrg. 1851, p. 272-277, taf. 11.

Morsacn, L., :07. On the Light Receptive Function of the Marginal Papillae of Gonione-
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Mureacn, L., and Surarer, C., :03. On Medusae from the Coast of British Columbia
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Murray, G., 99. Exploration of the Intermediate Depths of the Ocean. Geogr. Journ.,
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Nurrine, C.C., :01. The Hydroids. Papers from the Harriman Alaska Expedition, no,
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All figures from unretouched photographs of preserved specimens.

Fig. 1. Pelagia panopyra, seen obliquely from the oral side. X 2.

Fig. 2. Atorella vanhéffeni, sp. nov. Especially worthy of notice are the phacelli, gonads,
subumbral plates, coronal furrow, and exumbral nematocyst warts. x 8.

Fig. 3. Periphylla hyacinthina, natural size.

Fig. 4. Charybdea rastonii. x 2.

Fig. 5. Aegina citrea. x 1.5.

Fig. 6. Cunina peregrina, sp. nov. The form of the gastric pockets is particularly well
shown. xX 3. |

**Albatross”’—Eastern Pacific Ex. Medusae, Plate 1.

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All figures from unretouched photographs of preserved specimens.

. Amphogona apsteini; side view. x 8.

. Amphogona apsteini; oral view.

. Solmundella bitentaculata. x 12.

. Colobonema sericeum; oral view. xX 1.5.
. Colobenema sericeum. X 1.5.

. Aglaura hemistoma. x 8.

. Crossota brunnea. x 2.

. Rhopalonema velatum. x 5,

“‘Albatross”—Eastern Pacific Ex.

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PLATE 3.

All figures from photographs of specimens preserved in formol.
9
In these two figures the form and extent of the gonads, and of the manubrium,
is well shown.

Halicreas papillosum; oral view of immature specimen, especially to show the
conformation of the gastrovascular system. Exumbral papillae are as yet
but slightly developed. x 3. ;

Gonionemus suvaensis; oral view, illustrating especially the extent of the gonads
along the radial canals. x 4.

Gonionemus suvaensis; side view. X 4.

Liriope tetraphylla; side view. The gonads exhibit the rhomboid form character- _
istic of the “compacta” stage. From a specimen 22 mm. in diameter.

Liriope tetraphylla, a younger specimen. The gonads are triangular; “rosacea” —
stage. From a specimen 15 mm. in diameter.

‘“Albatross’—Eastern Pacific Ex. Medusae, Plate 3

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PLATE 4.

All figures from unretouched photographs of preserved specimens.

Fig. 1. Olindias singularis. x 2.

Fig. 2. Liriope tetraphylla, young specimen 4 mm. in diameter, before appearance of
gonads.

Fig. 3. Liriope tetraphylla, older individual 7 mm. in diameter; gonads are broad — oval
or squarish.

Fig. 4. Aequorea coerulescens, specimen 45 mm. in diameter; oral view, showing particu-
larly the condition of the lower gastric wall, and the numerical relation of radial
canals to tentacles.

‘*Albatross’—Eastern Pacific Ex.

Medusae,

Plate

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ae

SoG
on

. Eutima levuka, immature specimen; side view. xX 4. ?
. Eutima levuka; oral view of another specimen, showing four large tentacles, an
J

4, Sibogita simulans, sp. nov.; side view of type. x 1.5.
. Aboral view of the same.specimen. ‘The blind terminations of seven of the eigh

. Phialucium comata, sp. nov. ; oral view of type specimen 7.6 mm. in diameter. |
. Side view of same specimen. This photograph gives a good idea of the form ¢

PuatTeE 5.

All figures from unretouched photographs of specimens preserved in formol. ;
Ptychogena erythrogonon, sp. noy.; oral view of a mature specimen 30 mm. i

diameter.
the form of the peduncle and manubrium. x 4.

adradial canals are clearly visible. The lateral flattening of the bell is norma

and was observed in life.

the bell in life, as well as of the extent of the gonads along the radial canals.
Eutimalphes scintillans, sp. nov. ; side view of type specimen 10 mm. in diameter
showing form of bell, peduncle and manubrium, and location of gonads o
radial canals.
Eutimalphes scintillans ; oral view of another specimen of about the same size. —

‘““Albatross’—Eastern Pacific Ex. Medusae, Plate

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Fig. 10.

COMOAAAP OD

PLATE 6.

All figures from unretouched photographs of preserved specimens.

. Proboscidactyla ornata var. stolonifera. x 8.
. Proboscidactyla ornata var. stolonifera; oral view. x 8.
. Cytaeis vulgaris. x 8.

Phialium duodecimalis. x 20.

. Ectopleura ochracea. x 20.

. Octocanna polynema;aboral view. x 4

. Bougainvillea fulva. x 8.

. Phialidium discoida. x 20.

. Phialucium comata, sp. noy., immature specimen 5 mm. in diameter; oral view.

Octocanna polynema., x 4.

“‘Albatross’—Eastern Pacific Ex. Medusae, Plate 6.

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PLatTE 7.

All figures from unretouched photographs of preserved specimens.

Fig. 1. Sarsia resplendens, sp. nov., type. x 20.
Fig. 2. Amphinema turrida. x 10.

Fig. 3. Zanclea gemmosa. x 25.

Fig. 4. Pennaria vitrea. x 8.

Fig. 5. Amphinema australis. x about 20.

Fig. 6. Pennaria species (?) x 12.

Fig. 7. Purena brownei. x 8.

Fig. 8. Sarsia coccometra, sp. hov., type. x 6.
Fig. 9. Stomotoca divisa, natural size.

‘“Albatross”—Eastern Pacific Ex. Medusae, Plate 7.

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PuLaTE 8.

Atolla wyvillei; aboral view. From colored sketches taken from life on

“ Albatross ” by A, M. Westergren and the author. Natural size. a

PuateE 9.

All figures based on colored sketches made from life on board the “ Albatross.”

Fig. 1. Periphyllopsis braueri, natural size. The marginal lappets are somewhat
restored. The coronal furrow is well marked.

Fig. 2. Periphylla hyacinthina (“dodecabostrycha” stage); oral view of very you
specimen, 10 mm. in diameter, to show restriction of endodermie pigment to

the central stomach and rhopalia.

a
iQ

ig. 3. Atolla wyvillei; seen obliquely from the side, showing exumbral furrows
central disc. From a specimen 20 mm. in diameter.
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g. 4. Aeginura grimaldii ; oral view of female specimen. The secondary tentacles o
the margins of the lappets are somewhat restored. x 4.

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Charybdea rastonii, from preserved specimens.

Side view of half grown specimen, 13 mm. in diameter.

Aboral view of same, showing exumbral sculpture.

Oral view of same, with tentacles cut off; (c.v) velar canal ; (fr) frenulum; (t)
stump of tentacle.

Side view of rhopalium in its natural position in the exumbral nitch ; (oc), otocyst.
x 20.

Oral view of rhopalium, x 40. (01, o*) single ocelli; (0%, 0”) paired ocelli.

. Somewhat ideal dissection of apex of bell, to show depth of gastric cavity and

absence of mesenteries.
One of the gastric phacellae, x 30; to show type of branching.

Atolla wyvillei.

Oral view of central portion of the disc. On the right-hand side the lower gastric
wall and the gonads are dissected away to show the gastric filaments (g.f); gastric
ostia (g.os) ; ring sinus (1.8); and septal node (s.n); (go) gonad. Natural size.

Aboral view of central portion of disc of a specimen 8 mm. in diameter, in which
the radial furrows are narrow, as in A verrillii; the number of furrows is one
less than of tentacles. (ped) pedalium; (t) tentacle.

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PLATE 11.

Atorella vanhéffeni, sp. nov.

Side view of the type specimen, 5 mm. in diameter. The coronal furrow is

deeply marked. The color of the gonads is taken from a sketch from life made
on board the “ Albatross.”

. Aboral view of the same specimen, to show the radial arrangement of the four

gonads and phacellae, and the six tentacles.

Aboral view of exumbrella surface and base of tentacle, showing triangular
endodermal root of the latter (en.r); the exumbral nematocyst warts (n); and
the outlines of the subumbral plates (deeply shaded). x 50.

Side view of one phacella. x 70.

Longitudinal section of the distal portion of a tentacle, showing the terminal
nematocyst swelling (n). (en) endodermic core; (ec) ectoderm. x 125.

Rhopalium by transmitted light. x 100,

Rhopalium by reflected light ; (oc) otocyst ; (s) covering scale ; (b) bulbus. x 70.

Radial section through margin in plane of a rhopalium ; (oc) otocyst ; (s) cover-

ing scale; (en) endoderm; (ec) thickened ectoderm ; (g) mesogloea. x 200.

|
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Puate 12.

Periphyllopsis braueri; oral view, showing canal system. The walls of the
stomach are torn away, leaving only its base with the gastric cirri (ci.g). (¢.t) |
tentacular canal; (c.r) rhopalar canal; (c¢.1) lappet canal; (go) position of |
gonad; (r) rhopalium. Natural size. : |

Atorella vanhoffeni, sp. nov.; oral view of gonad. x 35. ‘

Atorella vanhéffeni. Transverse section of gonad (go), showing that it is a single
leaf-like structure attached to the endoderm (en) along one line only, at x. (g)
mesogloea, From a photograph. x 70,

Atorella vanhoffeni; oral view to show canal system ; (¢.r) rhopalar canal; (e.t) |
tentacular canal; (os) gastric ostium; (go) gonad; (r) rhopalium, The adja-
cent tentacular and rhopalar canals unite in the marginal lappets. x 14.

Nausith6e punctata. Rhopalium showing ocellus (0) and otocyst (o¢.) (se)
covering scale. x 125.

Nausith6e rubra; rhopalium. (0c) otocyst; (sc) covering scale. There is no
ocellus. From a photograph. x 60.

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Fig. 5.

. Oral view of a small segment of the gastric wall, with gonads (go); gastric .
. Portion of the gastric wall, viewed from within; (g.os) gastric ostia (openings

. Rhopalium, aboral view; (p) exumbral sensory pit; (s) covering scale; (x) rho;

Pate 13.

Poralia rufescens.
b

Oral view of the best-preserved specimen. ‘Those portions of the margin whiel
have been reconstructed are indicated by dotted outlines. Reduced one half.

ments (g.f) and bases of canals (¢.ra). x 1.5.

of the radial canals); (go) gonad ; (g) gelatinous substance of the dise. 2.
palium. x 15.
Dissection of margin with side view of sense organ; (p) sensory pit, seen througl
a thin layer of the mesogloea; (s) covering scale; (0c) otocyst at the tip of the
rhopalium ; (r.c) rhopalar canal. x 30.

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All the figures are from sketches of living specimens made on board the “ Albatross.” :

Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.

PuLate 14.

Pegantha smaragdina, sp. nov., type; natural size.
The same; side view.

Pegantha triloba. x3.

Cunoctantha octonaria. x 15.

Aegina citrea; specimen 16 mm, in diameter.

. “= ne A
TALBATROSS EASTERN PACIFIC EX MEDUSAE PLATE 14.

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Puate 15.

. Cunina peregrina, sp. nov., type; side view; from a sketch from life made on board

the ‘* Albatross.” x 5.

. Cunina peregrina; immature individual, 3 mm. in diameter, aboral view. At

this stage there are only three or four otocysts per marginal lappet.

. Cunina globosa, oblique side view, from life. x 5.
. Cunoctantha tenella, sp. nov., type; from life. x 10.
. Cunoctantha octonaria; immature individual, 1 mm. in diameter. At this stage

there is only one otoeyst per marginal lappet; there is as yet no trace of the
formation of gastric pockets.

}. Cunoctantha octonaria ; aboral view of another specimen at about the same stage

of development.

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Puate 16.

Pegantha laevis, sp. nov., type; side view, from life. x 2.

Cunoctantha tenella, sp. nov.; immature individual, 2 mm. in diameter, in
which there is as yet only one otocyst per marginal lappet.

Pegantha triloba; immature individual, 2.5 mm. in diameter, with seven
antimeres.

Aegina species (?); immature individual, 5.6 mm. in diameter (see p. 74). This
figure is incorrect as it does not show the interradial septa which are present in
three of the four quadrants and separate the gastric pouches.

Solmissus marshalli. In the lower half of the drawing the marginal zone is
dissected away to show the form of the gastric pockets. Only the basal —
portions of the tentacles are shown. Natural size.

Solmissus marshalli; immature individual, 28 mm. in diameter, with only eight
antimeres.

FROSS LASTERN-PAGIEIC Ex ——_—

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ned { am
hy
‘ -
a
7)
De’ ‘
&
‘7
= 5 {
ve
t?
L

bo

a8

. Aegina alternans, sp. nov., type; showing the undivided gastric pockets.

. Cunina globosa; tip of tentacle densely packed with nematocysts (n).
. Cunoctantha octonaria; rudimentary lateral otocyst, in which no otoliths are yet

a

PLATE 17.

interradial in position, and equal in number to the tentacles. x 1.5.

Cunoctantha octonaria. Marginal lappet of half-grown individual showing the
well-developed median and rudimentary lateral otocysts (oc), and otoporpae (op)
x 60.

formed ; (en) endodermic core. xX 250.
Cunoetantha octonaria; fully formed median otocyst, containing one large otolith)
(ol) ; (op) otoporpa ; (n) nematocyst. x 250.
Cunoctantha tenella, sp. nov. Margin of one lappet, with three otocysts (oe),
all well-developed; (en) endodermic core of tentacle; (en.r) endodermic root
of tentacle; (n.p) nematocyst pad at base of tentacle ; (op) otoporpa. x 30.
Cunoctantha tenella. Otocyst. x 250.
Cunina globosa; otocyst (oc), and otoporpa (op). The shape of the latter is
characteristic; (n) nematocyst. x 250.

ALBATROSS EASTERN PAGIFIC EX. _

i Bigelow dei

n

S77 ae

Puare 18.

4
an
if

Fig.

og

ne

Po

5. Oral view of portion of lower gastric wall of a young specimen, 12 mm. in diamete

. 6 Four adjacent gonads (go) of a mature specimen, showing slight seconda

(fe

frie

PuLaTE 18.

All figures are of Pegantha martagon.
Side view of mature specimen 20 mm. in diameter.

Oral view of same individual,

Portion of bell margin, with otocysts (otc) and otoporpae (op). x 20.
Two marginal lappets of a small specimen, 5 mm. in diameter, showing one sm:
tentacle more recently formed than the other two; (v) velum.

showing an early stage in the growth of the gonads (go), which are still simy
globular swellings; (¢.per) peronial canal.

lobing; (c.per) peronial canal. x 6.
Otocyst and otoporpa; (ol) otolith; (ec) ectoderm, and (en) endoderm of otocys
(op) otoporpa, bounded by cap-like cells; (n) nematocyst. From a specim
stained in borax-carmine. Bristles were seen in life, but are destroyed |
preservation. x 300.
Somewhat diagrammatic cross-section through marginal zone in radius of a gona
to show the gelatinous genital prominence (g.pn) which supports the centi
region of each gonad (go); (e.c) circular canal. Fyrom a dissection.

ee

5. Meisel lah Basten

4

Piate 19,

=z
9
bo

PuaTE 19.

Pegantha smaragdina, sp. nov.

Rudimentary tentacle, connected with otoporpa (per) replacing an otocyst on the
bell margin; (en) endodermie core of tentacle. x 300.

Oral view of a segment of the disc of the type specimen showing conformation of
the gonads, and canal system. x 2.

Otocyst containing five otoliths (ol), and otoporpa (per). Xx 300. (n) nematocyst.

Optical section of tentacle to show core of chordate endoderm cells (en); (ec)
ectoderm. x 16.

Aboral (outer) view of three marginal lappets of the smaller specimen, showing
parasitic larvae, in polyp and medusa stages, lying in the gastric cavity and
in the peripheral canal system of the parent-host. x 6.

Dissection of bell showing endodermie tentacle root (en.r); gonad (go); perona
(per); (t) tentacle.

Radial section in plane of a gonad in the mature specimen, to show the gelatinous
genital prominence (g.pr) which supports the gonad (go); (¢.c) lumen of
circular canal; (v) velum. From a dissection. x 8. ~

Otoeyst in optical section; (ol) otolith; (ec) ectoderm; (en) endodermic
core. x 300.

Radial section of the immature specimen. ‘There is neither genital prominence

nor gonad; (g) mesogloea; (¢.c) cireular canal; (v) velum. x 8.

— ia is ail mip ye ~ ) thts eee). =.
‘ ae a yee + Fe . ;

te

MEDUSAR PLATE 19.

mm

maui

It

!

I

i

EASTERN PACIFIc Ex—

Pest Ta 7 li 7
i o iy, -
i pe ¥ Pelee bas 9
ary an + U
One qs nih iP -_ J
U -
s , - ele Y
-
} aa
We 4
as
ee ‘4
'
1
7
7
ita ‘ {
.
rita?
. s,

iA | ee “10 i

Piate 20.

Fig.

>

PLATE 20.
Pegantha triloba.

Radial section through the margin of a specimen 11 mm. in diameter, before ap-
pearance of gonads, ‘in the plane of an otocyst; (v) velum; (ur.r) nerve ring;
(ot) otoeyst, (s.lam) stutzlamella; (op) otoporpa; (n) nematocyst ; (en.lam) endo-
dermic vascular lamella. The endoderm lining of the circular canal is much
thickened on its oral face.

Surface views of three adjacent gonads of adult, showing the three main lobes of
which each is composed ; in each the lateral lobes are secondarily subdivided.
x 8.

Surface view of otocyst and base of otoporpa (op); (ol) otolith; (en) endodermic
core of the sense organ ; (n) nematocyst. The bristles were observed on a fresh
specimen ; they are destroyed by preservation. x 300.

Pegantha laevis, sp. nov.

Aboral view of portion of lappet-zone of a specimen in which the gonads have not
yet appeared, showing two large tentacles, and a third small one of more recent
formation. x 6.

Surface (oral) view of three adjacent gonads (go) of mature individual; (¢.c)
circular canal; (per) peronia; (v) velum. xX 8.

Otoeyst (oc) and otoporpa (op); (ol) otolith; (m) nematocyst. x 300.

a

XLBATROSS EASTERN PAG

ric Ex-—-

“pM.

hh

chlan

S

Op.

a, ‘ 4 ,
= ‘si : ir
i. = - 7
- :
is ”
he, ea
i
. ;
ae
y

; Th x eras
f hinds 7 Pa oal onl ok
4 f 0) Se rive
a Wl Praise nih iL) ltin Sh ,itOait ioe bedi v
<5 Bien Sos Poewe) i Vi Ay yi
ey ; > Ld
_ 7 i : ; - =
h. UATE PNY | PAlaito- Lede Laat trkov ‘
*
OT gil iKiveon, Fis ode) olsmiggs yuday
® = i
altabnd asiw CY BAIT Oe SS OCeD . Fait erin y
16 fe a Hint we Hh ty yom [itiniore) *osfoul fy Feube
roel is ; AMS 3
(m4 ’ ‘ uh i
mentat & 1 : re F r
Pednee ou L4 Die du vi ue
Wieroud ay I F ’ i ¥.
Wage pris odd Nessie \ i
went alle i
uss 7 i ;
\
—$
+),
Yn
Le
i
: rf
' a vs

Fig.

Fig.
Fig.

bo

ot

PuaTeE 21.

Solmissus incisa.

Oral view of small specimen, 10 mm. in diameter. There are only one or t)
otocysts per lappet. Only a few of the tentacles are shown in their ent}
length.

Same specimen; a rudimentary tentacle; (per) peronia.

Same specimen; a young tentacle further advanced; the peronia (per) is mui
longer.

Solmissus marshalli, otocyst, surface view, with bristles. From life. »x 300.

Solmissus incisa; optical section of otocyst, from a specimen stained in bore.
carmine ; (ot) otolith. The bristles have all been destroyed by preservation. x 3()

Solmissus marshalli.

One marginal lappet with thirteen otocysts (oc); (per) peronium.

Oral view of two adjacent gastric pockets of a female, showing gonads (go). T
gastric wall is torn over the central region of each pocket. From life.

Radial section through margin in radius of an otocyst, to show the absence of
endodermic strand which might represent the ring canal; (g) mesogloea; (c)
otocyst; (nr.r) nerve ring; (s.l) stutzlamella. The musculature of the o1
side of the velum is indicated. x 150.

ALBATROSS ¥ EASTERN PACIFIC EX

2) 89
1@, 0 gite!
Bigelow del

»
s

i A Fibs
, i ek Peay
vein es i : :
oa 7 =
_—
eee,
e%
ae iA
i
—. 22S eee
;
toon. 7
at MM So matinee alicia ac Hits

ae. |
MPerinats MAT SST es A

oes af Poti) ot Pentite : Lorewy ie Ps alt rank f
piace feroda ti! aieslt peohjoesic ol iiss Sioubecsenrd i ;

, bond. i hu ridavod. sr Seed Pe wee cae

Peds whel creruld it wilh Rh jar oth au
te Heeie! one 1 bp Ji
“
,
,
. rr)
Me
in
; 4

ew
.
i

es) r _

PLATE 22.

Stages in the development of the parasitic generation of Pegantha smaragdina, sp. noy
All figures magnified 1600 diameters.
Specimens fixed in formol ; stained in Delafield’s haematoxylin.
Figs. 1-6. Amoeboid cells from the mesogloea, near the aboral gastric wall, close to "|
margin of the gastric cavity.
Fig. 5. An amoeboid cell in process of amitotic division.
Fig. 6. Amoeboid cell in contact with the endoderm (en).
Fig. 7. Mitosis in endoderm cell.
Figs. 8, 9. Mitosis in amoeboid cells; metaphase.
Figs. 10, 11. Two amoeboid cells in contact. This is the phenomenon which led Metsct
nikoff to believe that one cell might engulf another.
Fig. 12. Youngest undoubted stage in development of the larva, The embryo consist
of two cells, one, the nurse (n.ce), enclosing the other.

SS ae

Fig. 13. A slightly later stage. The nucleus of the nurse cell (n.n) has divided amitot. ;
cally. The inner cell, the future embryo, is in the metaphase of mitosis.
Fig. 14. Still later stage. The embryo is in the two-cell stage. The nurse cell in thi)
specimen has only one nucleus. .

MEDUSAE PLATE 22.

B. Meisel lth Goss

—

en) seek #1) oko 7 hr Aa} ae
Peak HOH) x Fat Bt |
Berio 10 Maen Mh 10.0)

Ay ats.

ps potalyory! WT aos

Reet SeIna ANY veroiliiess! woniaie gon ey

’ g 4 f *
: at LEN Pekan 8 lyse ita

)
moat (URLS abel o7 et bets
Pn he reverts hike
ft, myc wr} ) iSite it 4! o
aig WE yout a ¢ j ein) ’ nit is Wen ' mytii
mss ;
SMart? kik! ep Gliney Ley r, fay tew A870 4
Biysi | |
Mi PRET ARE Rae
a PLATE 23.
meveiionent eff te nolieotingia R

MPCs pins velo ,
Pe ee 7

ake

‘iw Peyarroholins cortw. i) bin ite

cd ie boera yond

ar Ditierg fears, f i 4 in 2 n
Tae jn abe tidy | 5

pyceras rf ate) olds ! bitin bor

mabibas Sure persis? lo noizacherilil a,

4°

ia _ ;

PLATE 23;

Stages in the development of the parasitic generation in Pegantha smaragdina, sp. nov.
All figures from sections. Figs. 1-7 x 1600; Figs. 8-11 x 900.

Fig. 1. Two-celled stage; nurse nucleus (n.n) in process of amitotic division.

Fig. 2. Four-celled stage; nurse cell contains two nuclei.

Fig. 3. A later stage with about twelve blastomeres. The cytoplasm of the nurse en-
closes large vacules and it has two nuclei (n.n).

Fig. 4. Slightly later stage, with about sixteen blastomeres. The nurse nuclei (n.n) are

flattened and cap-like.

Fig. 5. Section through morula stage, lying close to endoderm of parent host. One of the
blastomeres is in process of mitosis. No differentiation into ectoderm and
endoderm is yet visible. The cytoplasm of the nurse is now thin; (n.n) nurse
nucleus.

Fig. 6. Morula stage, surface view. The nurse nucleus (n.n) covers the embryo like

a cap.

>|

mie
gg

“i

. Section through slightly later stage. The embryo is now in close contact with the
endoderm of the parent (en). The central cells of the morula, the future en-
doderm, are now divided from the peripheral layer by a thin, but deep staining
layer, probably the earliest manifestation of the mesogloea. The cytoplasm
of the nurse is now exceedingly thin.

Figs. 8-11 are of larvae lying free in the gastric cavity of the parent host.

Fig. 8. Longitudinal section of earliest stage formed free in the gastric cavity of the
parent host. Ectoderm (ec) and endoderm (en) are now clearly distinguishable,
but there is as yet no trace of gastric cavity. From a specimen stained in
borax-carmine,

Fig. 9. Section through slightly later stage, in which endoderm (en) and ectoderm (ec)
are separated by a distinct mesogloea. Ectoderm and endoderm cells now show
a difference in size.

Fig. 10. Section through later stage; the ectoderm (ec) and endoderm (en) cells show
differentiation, the former being small and cubical, and staining deeply; the
latter large, chordate, and staining but slightly; (s.lam) mesogloea.

Fig. 11. Still later stage, in which the differentiation of ectoderm and endoderm cells has

progressed even further. The larva is now elongate.

ALBATROSS EASTERN PACIFIC EX. MEDUSAE PLATE23

en.

Bigelow del

? 7 rs i
ioe ae
Maes hs
o_O ae
Teil
ait
yh 7
i P
va ;
bE #1;
i 1 ’ 7 i
= Fide ey oid ;
SLATE AST A ETD i P ' |

Be Cisioag 0 GOswimr OF suing Qe, \» cheesey
Bh vind a hetcee st certain shen wit A irdits [eit
. pe Ney MaIKti du ul . Vy at 7 eo

ry
Op 1 i
Ph or (iis iy eeAT j
we
oot bee a {
ili) fastvis oi. de othe, a) eyiky ieee ren aly wari
ere
" ti net
ian eT! F i Net Sit tg ‘ft
whet ri }
mi F ~
ay Dany cP aPUoMil H ; r
it it bo. Ou i Tatas Tie |
¥ 7
y iy ne ryt ; j ri { fev
mm POMOT Lost : i rad uf 5 , il i j
Poi ss as
i unr Keys) O47 et Pe ae | Thy my mond
PTH) Ouevte 9 Ve i {Apne ] i 7
PASSPORT thy Weal % TA vy i |

Prepoboos whist (i bed sae

es f ‘1 aia

woe oOffo To wethnorty PATE Oe 08

4 »>
——— &

“

PLATE 24,

Stages in the development of the parasitic generation of Pegantha smaragdina, sp. nov.

Fig.
Fig.

Fig.

Fig.

al

9

ae

Longitudinal section of a larva, just prior to formation of gastric cavity. x 900.

Longitudinal section of a larva in which the gastric cavity (g.cav) is formed, but in
which the mouth has not yet broken through. The greater bulk of the larva
forms the primary tentacle; and the endodermic core (en.r) of a second tentacle
can be distinguished. x 900.

Somewhat diagrammatic longitudinal section of a larva in which the mouth is
opened, showing the earliest stage in budding at the aboral pole ; (en.r) endo-
dermic core of tentacle. x 300.

Surface view of the stage represented in figure 1. The main body of the larva is
probably the future primary tentacle. x 300.

Somewhat diagrammatic longitudinal section through a larva with bud constricted
off from gastric cavity; (en.r) endodermic core of tentacle; (m) mouth.
Reconstructed from three successive serial sections. x 300.

Diagrammatic longitudinal section through aboral region of a larva with two
buds. The distal bud has an open mouth and a rudimentary tentacle ; its cavity
is entirely constricted off from that of the proximal bud. The cavity of the latter
is still connected with the gastric cavity of the parent larva. x 400.

Medusa stage, radial section through margin in plane of otocyst; (ot) otolith; (g)
mesogloea; (s.lam) stutzlamella; (en.lam) vascular endoderm lamella; (n.r)
nerve ring; (v) velum. x 500.

Similar section of a very early stage in the formation of the otocyst (ot). The
endodermic core of the otocyst is still continuous with the endodermic lamella
(en.lam). x 500.

PLATE 24

EP

MEDUSA

‘er

ALBATROSS EASTERN PACIFIC EX:

= Sy oe

‘™

he

en lang,

en tam.

Salers,

—

en's
i=)

e/eielel

Bigelow del

; )
ee \d ‘
: .
, — ie
: :
c a
as #
r
a. i
a
4
ia Alingoed } ”
Lips’ to “a > Gs at {
"
am a by |
Batis ko saaroay):6 es!
Mae yunthdid * ih 7 ' ;
Repaired: €8 elowig:
_
10 a - : ;
US Whi
leno: j } iy
<r Puate 25. ;
any Hy: 5 ; PROT
Mite mise! ;
q ay
poets tery A, :
> ’
~ ofa , Ray
’ vey ‘i '
1
. 5
ji
/
oe
a tt
9 i
}
‘
val
7 q
rl ,

Puate 25.

Stages in the development of the parasitic generation of Pegantha smaragdina, sp. nov
The specimens were all taken from the peripheral canal system of the parent-host.

Figs. 1-9. Stages in the development of budding larvae.

Figs. 1, 2. The youngest stages, showing the first appearance of the primary tentacle
These larvae are probably the product of budding, because in larvae de
veloped from the egg the primary tentacle is formed earlier. x 150. |

Fig. 3. Slightly older stage, with two tentacles. x 150.

Fig. 4. The earliest stage which shows budding. The future bud is represented by ¢

projection of the aboral pole. x 150.

Fig. 6. Slightly later stage. The bud is now partly constricted off. The tentacles are

long, and the open mouth is visible at the oral pole. x 150.

Fig. 6. Later stage. Constriction of the bud is now practically complete. x 100.

Figs. 7-9. Larvae showing the formation of two buds before either is constricted off.
x 100.

Fig. 7. Earlest stage when this process can be demonstrated ; second bud being formed)

from the aboral pole of the parent larva. x 150.
Fig. 8. The primary bad now has one well developed tentacle, and a second smaller)
one. xX 100.

Fig. 9. The primary bud now has an open mouth and two well-developed tentacles ;
and it is nearly constricted off from the secondary bud. The latter presents)
the condition seen in the bud in Fig. 6. It is probable that the latter is the
result of such a process. x 100. ;

Po
STERN PAGIFIG EX- —— MEDUSAE PLATE 25.

LAA Bosten

o
OR OW
a. |
“ ~
ry ein, Nb ii mallards F "
repeat at. woe!
. 00. sealants:
waisagae! aiteie i
aeioa? Pas sisaplmorny Ww ‘

Ly

Mert Ierecden an’ wate tre

AN i pave 4 ,
for <i Hf i
- bs j
ae PPL '
“43
mired ¥ pri

7 Lo
' ’ ne Ih Pie
i, D
as ° oe I
-;; 1s)
,
72

my 03 i

re]

a

:
f

[s‘e4e8r >

eh
a
1 cm

:

Late stages in the development of the parasitic generation of Pegantha smaragdina, sp. nov.
. 1. Early medusa stage with seven tentacles. The bell margin is indicated by a

Fig

Fig.

Figs. 8,9. Two successive stages in the development of otocysts (oc) and otoliths.

Fig. 10. Tentacle and peronia (pr) of the specimen shown in Fig. 5. x 100.

. Side view of still further advanced stage. The general outline is now flattened.

. Aboral view of an older medusa. The typical medusa outline has been assumed.

. The oldest stage taken. There are two otocysts in some of the lappets. Pe-

. Early stage in the development of an otocyst, in optical section; (ec) ectoderm,

ig. 7. Twin otocysts (oc). In only one has the otolith been developed; (en) endo-.

PLATE 26.

coronal thickening just oral to the tentacles. x 50.

. Aboral view of slightly older medusa, with eight tentacles. The ridge repre- —

senting the future bell margin is now prominent, and the aboral surface is
flattened. x 50.

There are nine tentacles of different sizes. x 50.

There are now ten tentacles. Otocysts have been developed (one per marginal
lappet) and the marginal lappet zone has increased in width. x 365.

ronii are developed. From a specimen stained in borax-carmine. xX 35,

(en) endodermie core of future sense organ, the position of which is marked on
the exterior by a slight prominence. No otolith is yet formed. xX 250.

dermic core. x 350. of

x 350.

MEDUSAE PLATE 26.

B. Mevsel (dh Basten

f
2
, ee iF
OS 3M * erert dent. Qe ae heen?! iste Aly ey) j i
woeea -fy) wi ei i Ta
este § (59) j clisgeiggite.(hoenits ; Lords ig
Ne) reer Sy waxsliogio (og)! Ue itew. ti: | ane
< Qa .
PLATE 27.
wa. em} ys } ;
7 -
egress iid f \
Yo): 12 6 H
. if mils

Fig.

PLATE 27,

Stages in internal budding in Pegantha laevis, sp. nov.

. Surface (aboral) view of a portion of peronial and ring canal showing budding. ©

x 35.

2. A budding ridge or stolon dissected out. Surface view. x 200.
. Cross section of ring canal in plane of a stolon; (g) mesogloea; (c.c) lumen

of the circular canal; (s.lam) stutzlamella; (ec) ectoderm; (en) endoderm; —
(v) velum. xX 250.

. Section through a stolon, more enlarged, (ec) ectoderm of canal; (en) endoderm;

(s.lam) stutzlamella. x 350.

. Section through bud formed directly from endoderm (en) of canal. The ecto-

derm is not shown; (s.lam) stutzlamella. x 500.

. An older bud, in morula stage, lying free in the lumen of the canal. The

ectoderm of the canal is not shown. Lettering as above. x 500.

. Same stage in surface view.

Cunina species (?)

. Budding stolon taken from the gastric cavity of a Solmundella bitentaculata,

x 100.

ALBATROSS EASTERN PACIFIC EX MEDUSAE Phare 27

*<

| Lote —_ | %

geibbid Lanseta yi
gir paths Pemysi: a
i —
bee, oy 4 ia al ree
ATOR ph sw s' g
; Aw! * rand den
T = in, 1 { f ‘ ,

B® sloniast GS 'O GORi0 80) ai pesaacqrri* ‘ t
Bast bas peu ys le eigen: wit ito catielfcte 4) o
— Pate |

dp yi r CD

yoohirrasar 5 Fj

— J
pats

pd endl GHot GAOL ie tee t é pe) i Bi

od efaihy

aw ;
bootie (1 Arya 1 45 iralagitin

PuaTE 28.

Cunina peregrina, sp. nov., stages in internal budding.

Fig. 1. Surface view of two adjacent gastrie pockets, showing endodermal thickenings
and budding. x 10. "

Fig. 2. Surface view of one corner of a gastric pocket, showing active formation of
endodermal ridges, or proliferating stolons, and buds. x 100.

Fig. 3. Surface view of one such stolon, x 300.

Fig. 4. Radial section through a gastric pocket, in the plane of the tentacle, showing the
location of the stolons near the margin of the pocket, and their relation to
the gonad (go); (g) mesogloea; (t) tentacle; (n.p) nematocyst pad; (v) velum;
(s.lam) stutzlamella; (ec) ectoderm; (g.cav) cavity of the gastric pocket.
x 100. 4

Figs. 5-7. Three successive stages in the constriction of the bud, b%, from the buddi

stolon, b!, showing the endodermic nature of the latter. In Fig. 5, t
bud is but slightly constricted, in Fig. 6 it is almost separated, and in Fig. 7
it lies free in the cavity of the gastric pocket, though close to the stolon
(b*); (ec) ectoderm ; (en) endoderm; (s.lam) stutzlamella. xX 350.

ALBATROSS EASTERN PAGIFIG EX

seenenaa CON

ze

elk.

enn Slam

Sam

Bigelow del

7

PLATE 29.

ioe.
Fig. 2.
Fig. 3.
Hig. 4.
Fig. 5.
Fig. 6.
Fig. 7.
Fig. 8.
Rigien9:
Fig. 10.

PLATE 29.

Tetrorchis erythrogaster, gen. nov., sp. nov.
Side view of the type specimen: the color of the manubrium is taken from a sketch
from life made on board the “ Albatross.” x 4.
Side view of margin of bell, with large radial tentacle opposite the fertile radial
canal; (go) gonad; (en.r) endodermic root of radial tentacle ; (¢.c) circular canal;
(v) velum, x 16.
Base of one of the small tentacles, with rounded endodermic root (en.r). 100.
Aglantha digitale, var. intermedia, var. nov.
Side view of mature specimen, 14 mm. in diameter, showing the form of the)
gonads and bell, and the muscular condition of the subumbrella.
Oral view of the same specimen, showing the stumps of eighty-eight tentacles.
Peduncle, showing the course of the radial canals, and manubrium with the mouth
widely open, showing the absence of separate lips. x 10.
Peduncle and manubrium, with mouth closed. The ridges thus formed suggest
the presence of four long lips. x 10.
Manubrium with lip region everted, showing the endodermic pigmentation of the
lining of the gastric cavity. From a sketch from life. x 10.
The youngest specimen taken, 2.5 mm, high, There is as yet no peduncle, and}
no trace of gonads.

represent the earliest visible stage in the development of the sexual organs.

MEDUSAE PLATE 29.

VATROSS EASTERN PACIFIC EX:

mp pula!
ot
memiene feiss ye:

Sieys iD H) ; in

putes Vale
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10

PLATE 30.

Gossea brachymera, sp. nov.
All figures except Fig. 3 are from photographs.

General side view, from preserved type. x 10.

Oral view of the same specimen. x 10.

Diagrammatic drawing of one quadrant of the bell margin, showing arrangement
of marginal organs ; (t.ra) radial tentacle; (t! and t?) primary and secondary ten-
tacle of each tentacle group; (¢.ra) radial canal; (¢.c) circular canal; (n.p)—
nematocyst pad. x 20.

Photograph of a similar quadrant ; (t.ra! and t.ra®) primary and secondary mem-
bers of radial tentacle group. The interradial tentacle group is likewise com-
posed of two members. The adradial tentacles are simple ; (go) gonad; (¢.ra)
radial canal. x 30.

. Base of interradial tentacle, showing position of otocyst (otc). x 60.
. Two radial, and an interradial tentacle, showing nematocyst rings, and absence of

sucking pads. x 60.

. Interradial tentacle group; oral view, showing the primary and secondary mem-

bers, t! and t2 x 60.

. Side view of the same, showing especially the spur-like form of the secondary ten-

tacle (t®), and the form of the nematocyst pad (n.p). x 60.

. Aboral view of same. :
. An adradial tentacle still more enlarged; its solid endodermice core (en) is clearly

visible. x 90.

-acific Ex

Eastern I

‘*Albatross”

|

x
Cs
3

T.RA.

‘oS

Fig.

a
ioe}
Oo oho

PrATE Sle

Olindias singularis.
General view. xX 2.
Aboral view of the same specimen, showing the blind centripetal canals.
Side view of a portion of the margin, showing the position of the otocysts (oc) at
the bases of the primary (exumbrella) tentacles (t.ex). x 8.

4. A portion of the bell margin; (t.ex) primary tentacles; (tv) secondary (velar)

tentacles ; (t.b) tentacular bulbs. At the base of each primary tentacle there
are either one or two otocysts. x 6.

A portion of the same, more enlarged.

Manubrium, showing the complexly folded lips. x 4.

Tip of a secondary (velar) tentacle, with terminal nematocyst knob.

Tip of a primary tentacle ; (s) sucking disc.

A portion of a secondary tentacle, to show arrangement and extent of nematocyst
bands.

. Base of a primary tentacle with two otocysts; (oc) otocyst; (ot) otolith; (t) ten-

tacle. In one otocyst there is one; in the other, there are two otoliths. x 25.

1

MEDUSAE PLATE31.

4
z

ALBATROSS EASTERN PACIFIC #2

> aL ire

RDS

s
a
SS
Nera

a8 @
aE
3

>,

ay

SS oe

pnt 329922 PII,
Oe ae
Fit Rx pana

PSs MNS TIN):
SS yD Mn mays

She
AY ay
Ae

=

i spn A MVPPNPIA ID zp HM PM: pM,

ey Sa) Dayuaateeety
¥ » p77», =

j in
i ay I.
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my Dyn)

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IYI EDWIN)
2
p

ep, =
My),

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i ; as.

ec res a

“Bigelow del

aie
i) ae
i
y Ui
vy
1 by oa
r Mets
‘ te,
se ' ‘
:
bas P
ae

. ge yays shan a Lah Bal yer chy
i , ;

PLATE 32, —
’ ; 1
\
i ‘ \
PERLSTTEY OL T201..:
be
A ee

le

Fig.

Fig.
Fig.
Fig.
Fig.
Fig.

Fig.

Fig.

. Alittle more than one quadrant of the bell margin, with tentacles and otocysts.

. Dissection of bell margin, showing endodermal roots of tentacles. x 40.
. Portion of tentacle, showing sucking disc. From a specimen stained in borax-

. Side view of manubrium. x 20. .
. Gonad by transmitted light; from a specimen cleared in glycerine. x 35.

. Portion of margin showing bases of two tentacles, and otocyst containing one

. Abnormal individual, 7 mm. in diameter, with only one radial canal and one

. Abnormal individual, with nine gonads and two distinct gastric cavities. x 2.

PLATE 32.

All figures from unretouched photographs of preserved specimens.
Gonionemus suvaensis.

Only three of the latter are visible. x 20.

carmine. X 75.

otolith. x 75.

gonad.

Olindias singularis.

-

‘+ Albatross’—Eastern Pacific Ex. Medusae, . Plate 22

BIGELOW PHOTO

4 ne
y
wet
ners
7 as

Ste
Panrwane’ peed alr
- <a
mG aval aottdbess3
eg; sor err +f
oti § aiit worty j t
Olivain) wi
i¢ te
oa 1
‘
. 7’
¢
Gaye febyr i
ty BPR ines

of polyine.f t.ci4 May

.
: x
af
PT
(*
BB
ws
‘
i
i

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5.
Fig. 6.
Bigs te
Fig. 8.
Fig. 9.
Fig. 10.
Fig. 11.

. Halitrephes maasi, gen. noy., sp. nov. Tentacle base, showing endodermice roo
. Halitrephes maasi, tentacle, showing differentiation into proximal and d

. Halitrepbes maasi. Somewhat diagrammatic section through bell margin tc

. Halitrephes maasi, oral view of type. The position of the gonads is indicated

PLATE 33.

(en.r). x 20.

regions. X95.

illustrate relation of endodermal root of the tentacle (en.r) to circular cana.
(c.c); (v) velum ; (g) mesoglea.

by the shaded areas at the bases of certain of the radial canals. Slightly
more than natural size.
Halitrephes maasi. Proximal portion of tentacle in optical section, to show its
core of chordate endodermie cells ; (en) endoderm core.
Homeonema alba, otocyst. From a photograph. x 250,
Halitrephes maasi. Tip of tentacle, closely crowded with nematocysts. x 30.
Halicreas papillosum, otocyst ; (en) endodermic core. From a photograph. x 28
Halicreas papillosum. Segment of distal portion of tentacle with the ectoderm
partly stripped off, showing the endodermie core.
Halitrephes maasi, otocyst. x 150.
Homoeonema alba; one octant of bell margin ; (en.r) endodermic root of the
large radial tentacles (t.ra) of which only the stumps persist; (ote) otocy
There are stumps of fourteen interradial tentacles. From a photograph. x 15

AE PLATE 33.

MEDUS

B. Meisel le Baste

: on
a
A ;
7 ve 7 \
SY J
est):
a if
‘ A
it ee
- vi sips +f
A
i
a
0 GAY pwANt 7) eras i
; 4
ri tan
Ce ‘Sark l
Ps. oh ab a2 tier li it HE idk
oe Eales inert or iil a

vi (aa-st) faiiuettess fhe ay 1) ce nhs ures

7 Yih nore Mi onieida feng) ollie di "

H

fone i ie g i y I , {
» ¢ * , t
Peat a if “) $
si - :
Boney How)’ AA du
Wi
r WATE Fite 1a)
IM d
‘ ,
my { . t 1 : ae
;
is i? j } Ty} ft)
t j vi
i ou, i
eT ieee iy 4 ii
0 i
. i er any AY i
4 ; f ‘ass Mt
' .
ha) nee oleae) idtent! janie tisiiq ded await ng
Ay
aes
if
i
AY
ry i
7

iy

igee<e
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Bigs Mie
Fig. 8.
Bigs 59:
Fig. 10.
Fig. 11.
Fig. 12.
Fig. 13
Fig. 14.
Fig. 15.

. Otoeyst. (Cf. Fig. 10, Pl. 45.) x about 100.

Puate 34.

All figures from unretouched photographs of preserved specimens.
Halicreas papillosum.

Oral view of about one-half the dise of an adult specimen, showing position of the
gonads (go), radial canals, and exumbral papillae (p.ra). x 2.

Portion of bell margin, with marginal organs, particularly to illustrate the
difference in size between radial (t.ra), and adradial (ta.ra) tentacles; (c.ra)
radial canal; (otc) otocyst. x 10.

Oral view of an exumbral papilla (p.ra), showing its secondary projections ; (¢.ra)
radial canal. x 5.

Homoeonema species (?); one octant of bell margin with marginal organs; (t.r)
radial tentacle; (t.ira) interradial tentacle; (ote) otocyst. x 20.

Halicreas papillosum, distal portion of tentacle; (en) chordate cells of endo-
dermic core. x 40.

Oral view of Homoeonema species (?) xX 5.

Tentacles of Halicreasidae.
Homoeonema species (?); tip of tentacle thickly clothed with nematocysts. x 40.
Halicreas papillosum; transition region between proximal and distal portions.
x 40.
Homoeonema alba, tentacle tip. x 40.
Halicreas papillosum, tentacle tip. x 40.
Halicreas papillosum, entire tentacle, showing differentiation into stout proxi-
mal, and slender spine-like distal portions. x 20.

Amphogona apsteini.
Transverse section through two adjacent gonads; both female and containing
large ova; (en) endoderm. X about 50.

Margin, showing tentacle stumps, radial canals (¢.ra), and spherical gonads —
(go). x about 50.
Manubrium and peduncle ; (c.ra) radial canal. x 20.

‘*Albatross’’—Eastern Pacific Ex.

BIGELOW PHOTO.

Medusae,

Plate 34.

C.RA.

GO.

Sra

ARE OOR ECON

OE,

PUAEUNSLARIENE

BOSTON

RA,

Oe

:
b HLA
, . 7 , = a
fnnienmt dire igrane tied jo ite 7 ave £
, j ey ;
OG gooda x .ddaG (ato) jo hey (00d) ) Gee d
A 1 :
ft , , 7 .
AY Frum breig) quiwode maw aot RRL wr |
dee : ‘
7 ' 4 , - haf } i.
- ie enamalriany 2xtoup
Rey “ é : ) ray rn ’ F =. a
; ees. f :

> «=
Ir 7
~ re
ar a a4) } en, nf ong cred a
ARTY CRAY) yee re - —
ofr Pag” wie Age Bi
- \ , :
;
7 ll Oe h )
a = ®
YF: -
7
La 7
Ae ?
- a
a =

Fig.
Fig.
Fig.

DIAS TH

. Eutima levuka. Quadrant of bell margin, with marginal organs; (c.ra) radi

. Eutima levuka. Tentacle base showing lateral cirri (ci); (c.c) circular canal.

. Portion of bell margin showing radial canals (c.ra); gonads (go), and the very
. A segment of the gastric wall, showing conformation of the lips, and the bases of
. Portion of bell margin more enlarged, to show a twin otocyst (otc).

. Side view of tentacle base; (p. ex) excretory papillae. x 35.

PLATE 35.

All figures are from unretouched photographs of preserved specimens.

,

canal ; (t.ra) radial tentacle ; (otc) otocyst. x about 20.
Pe
x 30.

Aequorea coerulescens.

as
numerous and densely crowded tentacles ; (g) gelatinous substance. X6.
radial canals (¢.ra) of various sizes. X 6.

Oral view of tentacle bases ; (v) velum; (p. ex) excretory papilla. x 30.

Aboral view of tentacle bases; (¢c.ra) radial canal; (¢.c) circular canal; (v)
velum. x 30.

O.RA.

Go.

‘“‘Albatross’’—Eastern Pacific Ex.

P.EX. ©

BIGELOW PHOTO

OTC,

P.EX.

Medusae,

Plate 35.

~

~

Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10

. Side view of medusa, from life. x 5.
. Portion of margin, with otocyst containing four otoliths, and marginal cirrus;

. Aboral view of base of manubrium showing form of lips, and basal portion

. Portion of bell margin with marginal organs, tentacles, tentacular knobs, cirri, and

. Tentacle base, aboral view, (go) gonad. From a photograph. x 30.
. Bell margin showing tentacles, tentacular knobs, and otocysts (otc), and the

. Tentacle base seen from within; (go) gonad. Froma photograph. x 30.
. Tentacle base, side view; (ex.p) excretory papilla. From a photograph. x 30,

. Otocyst, containing two otoliths (otl). x about 200.

PLATE 36.

Eirene viridula.

(en) solid endodermic core of cirrus; (n) nematocyst. X about 150.

radial canals. x 15.

otocysts (ote). x15.

Aequorea macrodactylum.

extremities of the radial canals. x 10.

in life. x 3.

MEDUSAE PLATE 36.

B. Maise! bth Boston Oy

ne ani UE

E mi yo ae
Me AiG As fy Sied.sbos

7 .

Bi ma einyoots ods |: Wan diag att?

1
t1 Li? j
r
bY iO al | sy t
a HBS strode Ma
= i iy \
a + ke
Loe fi bint Rr iu Fae mites Lise Linn t
a ney ; ; =)
my ena eh Gr hi hh ial T'y
" as
Ritobiciiy hind vate rg cro
ae \ a A
ee bu

at ehhh Uieee PLATE
i uti Bie Ried sahem la ihe aad Pts ieee tr =
] S Tubs

yen iv WO ‘ ‘ i ve ee ea i yy 1 hd

’ ii =
; uf p
Pg WY tad pat ( ,
ict)
nt i
Reet Aaa, 14 Pei sten a aR Yost cp 4a] urs }
, , My
olwodp sigan
HF yldiaiy a CT ae ;
ies fin): leae bibs ay
wg (ou) ile ay

Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Fig. 7.
Fig. 8
Hig. 9!
Fig. 10.
Fig. 11.
Fig. 12.

Puate 37.

All figures are from unretouched photographs.
Eirene medusifera, sp. nov.

One quadrant of bell margin. ‘The positions of the otocysts are indicated by the
white arrows ; and the otocysts themselves (ote) can be seen on careful exam-
ination; (t.ra) radial tentacle. x about 20. a

Base of tentacle flanked by lateral cirri (ci). x 45.

Rudimentary tentacle, flanked by lateral cirri (ci). x 45.

Otocyst, containing two otoliths. x about 250.

Distal portion of radial canal, along which no gonad is yet developed, but which
bears medusa buds, b!, b’, in various stages of development. X about 50.

Lateral view of medusa with one side of the bell dissected away so as to show t ne
form of the peduncle (pd), and of the manubrium (mn). xX 10.

Radial canal (c.ra), bearing medusa buds nearly ready to be liberated ; (mn) man-
ubrium, and (t) tentacle, of medusa bud. Xx about 50.

Oral view of a portion of the bell, showing radial canal with gonad (go) bearing
medusa buds. x about 30. :

Phialucium comata, sp. nov., tentacle base and otocyst (otc). about 30. ;

Phialucium comata. Tentacle base showing lateral cirri (ci). x about 30. ,

Eutimalphes scintillans, sp. nov. One quadrant of bell margin. The positions
of the two otocysts are indicated by the white arrows. The otocysts themselves
can be seen on careful examination; (¢.ra) radial canal; (t.ra) radial tentacle
(go) gonad; (v) velum. x 10. 4

Phialucium comata. Portion of bell margin showing marginal organs. The
positions of two otoeysts, which are plainly visible, are indicated by white
arrows; (t.ra) radial tentacle ; (c.ra) radial canal; (go) gonad. x 15.

‘*Albatross”—Eastern Pacific Ex.

= ——
I = TRA
2 y
OTC.
el.
i
! f
OTC
3
Cl
4
. T.
PD.
CO.RA
s .
= »
CRA
Cu
T.RA.
RA
GO.

BIGELOW PHOTO

MN

ime

ae ee — oe Ca

Be

oT
; ty i
Raed e ire th tunhnup. > bl
o4 , -.
a a .
FO" ys it ; rou pert inf
PLaTE 38.
ogee?)
; { ;
)
¥ Ms Jd
i»
* os jee WGrle Cnt fy
¢

Fig. 1
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Bigs 7.
Fig. 8.
Fig. 9.
Fig. 10
Fig. 11
Fig. 12.
Fig. 15.

. Octocanna polynema; oral view; from preserved specimen; (1) lip; (go) gonad.

. Amphinema australis; one half of bell margin, with two large tentacles, an

. Amphinema australis. Cross-section of bell, through gonads (go) to show inter-

Puate 38.

x6;

Octocanna polynema; one quadrant of bell margin; (t.ra) radial tentacle; (t) rudi
mentary tentacular knob; (ote) otocyst; (p.ex) excretory papilla. x about 20.

Octocanna polynema; otocyst (ote) with otolith (otl). x about 75.

Phialium duodecimalis; oral view of a preserved specimen. x 30.

Phialium duodecimalis; one quadrant of bell margin, showing radial tentacles
flanked by cirri (ci) and otocysts (ote). x 50.

Phialidium discoida. Portion of bell margin showing closely crowded tentacle
with large basal bulbs and otocysts (otc). x 60.

Phialidium discoida; otocyst (otc) containing a single otolith. In many instances —
the otocysts contain several otoliths.

Ptychogena erythrogonon, sp. nov., cordylus ; (en) endodermie core; (ec) ecto-
dermic covering layer. x 75.

Ptychogena erythrogonon ; cirrus with terminal nematocyst cluster. x 75.

rudimentary tentacular knobs with ocelli (0). x 20.

radial position of the latter; (1) lip; (c.ra) radial canal. From a photograph
of a dissection. x 30.

Ectopleura ochracea; side view of preserved specimen. 50.

Ectopleura ochracea; aboral view of same specimen to show extent of exumbral

nematocyst ridges (nem).

_ ALBATROSS EASTERN PACIFIC Ex MEDUSAE PLATE 38.

en

Bigelow del

iat “Vr

i? ! 7).
See 7 ‘
Ai fener bu
t iy o ;

er
ae haar sit Mots Wiss

byasist (Diprsiae ei bY

u

i}

Rice ..Grremront mals
wx arses

J) panne Gatien
aia

: a v
PRS eM Oe rey Sa Lis

masts i a wit tott. adel

; . “.
o

7 a a
OS ft UTTOS TS, 12018 {

ye Ce 401.1%

(ito rent

C59 Tse hat

we! l
t
> i |
i
) Voutit by
Ii
Wy, Eyal ta ;
qe bev ise

Pirate sor! e

4 t j

‘rs

Mears adhd Popo onk pivot sey

wer

wy
te
'
fy bt b
ayant
Lei
rl sik
+ f »
LAAT? SE iW y JE)
' a
Delt a) Coat
hte oF
y )
i
a

r)

Fig.

. Side view of type specimen, from a colored sketch from life.
. Aboral view of manubrium and radial canal in a specimen in which the gonads

PLaTE 39.

Ptychogena erythrogonon, sp. nov.

have not yet developed. The diverticula of the aboral surface of the canal, be-
tween which the sexual folds later appear, are already formed. x 5.

. Aboral view of radial canal and gonad (go) of adult specimen, showing the isolated

genital folds (go) and the distribution of the pigment. xX 5.

. Side view of same. From a preserved specimen. X 5.
. Portion of bell margin of adult, showing marginal organs; (t.ra) radial tentacle;

(co) cordylus. x 5.

. Aboral view of a specimen 18 mm. in diameter. The manubrium is relatively

rauch broader than in adult; the tentacles fewer. The radial canals as yet show
no diverticulae. From life.

. Aboral view of manubrium of adult, showing widely open mouth, through which

is to be seen the junction of the four unpigmented lines which extend along the
aboral surfaces of the radial canals. From a preserved specimen. X 4

Turris fontata, sp. nov,

. Side view of type specimen, from a colored sketch from life. For details of bell

margin, see Plate 42. x 2.5.

MEDUSAE PLATE 39.

8 Mersol da Gosme

Bigelow del

7 ay ar ¥ % ' ham "7 i ts
Be* ot ROG m7 AIG eel ‘
big ladlel "

Pom BILE vot ell ain

= Bb oselT ee wlinog rea. (4 ri

7” 7 “i
q a.
me anh Bleed Ly |.

rorwone Gt f ; :

All figures from colored sketches made from life on board the “ Albatross.”
x 10. For details, see Plate 43.

2. Cytaeis vulgaris. x 10. For details, see Plate 43. —
ig. 3.

4. Lymnorea alexandri, aboral view, showing junction of canals at base of manu-
brium, and interradial position of gonads.
. Cytaeis vulgaris, aboral view of tentacle base, showing endodermic (brown)

syle

PLATE 40.

Sarsia coccometra, sp. nov., type.

Lymnorea alexandri. x 8.

and ectodermic (yellow) pigmentation.
Amphinema turrida. The outline of the figure is incorrect, in that it fails to
show that the two radial tentacular knobs are of larger size than the adradials.

See photograph, Fig. 3, Plate 43.

. Pennaria species(?) x 30.
. Sarsia resplendens, sp. nov., type.

SelPZ

x 25.

eo

PLATE 40.

EDUSAE

ME

ALBATROSS EASTERN PAGIFIC Ex

Bidelow dal

4)
-
7 Tas
rn
Th
ie j
a
» iy Th! y j } rhe { !
eR, Tes he . PLE oh
-O SeaeTeiiy: Gid SETI ee PUA S rt. ee Toe ‘ ‘ ith 7

at (2060! rn ane Fire tired! 7 : EL ae = i

ae i 2% Thi tii) = AWD Ay att 4 ' ti
emit awenal yildedla to vnvindiuiiwat To weed to weiy Low)
Bs.) aus sontisy ola we LeMti ) tend
Se EEOC 199M oy mi anh 4 ru Woy Se "
fs, ‘ -{ sy anea
- j
mnghmned: (een} 3.0) soaetn ly at A ae
: ie
La ee rites i 93 nrMeD

_ -Piate 1. Veebatrere died Sty ae

GRIN

. (hi. 70 i { aw 5 a I
‘ per
, iad b
4 J |
‘ £ i 4 .
1 4
@
; f
e sey oot t vil ;
’
‘ t
tava) ey it i { i y i
- f .t
i i ‘
j
nwt e & prevert 1 ’ ,
at

sh

Fig.

Fig. 2.
Fig. 3
Fig. 4
Fig. 5.
Fig. 6.
High is
Fig. 8
Hig. 9!
Fig. 10.
Fig. 11.
Fig. 12.
Fig. 13.

1. Side view of preserved specimen, 5 mm, in diameter.

Oral view of base of manubrium and radial canals (¢.ra), in a specimen 3 mm.
in diameter, in which the gonads (go) have appeared.

extension of gonads (go) along radial canals (c.ra).
Same view of a specimen 5 mm, in diameter, showing extreme extension of

. Oral view of base of manubrium of slightly larger female specimey, showing

gonads (go).

Base of tentacle showing pigment spot (0); (nem) nematocyst pad; (en) endo-
dermic core of tentacle; (c.ra) radial canal.
Portion of bell margin; (nem) exumbral nematocyst cluster; (c.ra) radial

canal.

Diagram of canal system in a large specimen.

ing blind terminations of adradial centripetal canals (cara); (c.ra) radial
canal; (go) gonad. x 3.
Sibogita simulans, tip of tentacle with nematocyst knob (nem). x about 15.

From a photograph. x about 30.

. Sibogita simulans, sp. nov., aboral view of apex of bell of type specimen, show-

==

PuaTe 41.

Proboscidactyla ornata, var. stolonifera,

Pandea violacea, one quadrant of bell margin; (t.ra) radial tentacle ; (0) ocel-

lus ; (¢.c) circular canal. x about 25.

Pandea violacea, side view of preserved specimen, 4 mm. in diameter.

Heterotiara anonyma, aboral view; (go) gonads; through an error these are

represented as per instead of interradial. x 3.

Heterotiara anonyma, side view of preserved specimen; gonads are inter-

radial.

XKoe

is Seal

, eo. —_- 22

B, Meisel (@ Bogor

MEDUSAE PLATE 41.

ALBATROSS EASTERN PACIFIC EX.

Bigelow del

mM
' r / J
bs ao :
=
=
ay
ey
Bass;
' ,
Giics)t! aire: ity
‘Tt See st
ppatdoth Oe ee |
tral! wee
ol
.. 4 ei
Bee owt 3 a
o Hees WW yowoh sin
PLATE 42.
is i
4
é Ly
bie) keh bs
v :
ty
ae Thy ;
tx ‘ie ten
LPs
i
ey. 5 ?
i i f h
Ke
Ast
Gee by
maiitl oars hed. my) 4 1S
ath ~

i
=

Slsided
i

joe
mT sea (J

ody
=
‘
-

Fig.

Fig.

Fig.

Fig.

o LO;

iba Ws

PLATE 42.

Tiara papua.

A very young individual, 2 mm. in diameter with long apical projection and

apical canal (c.ap). From iife.

Side view of a specimen, 5 mm, in diameter, with horseshoe-shaped gonads (go)

well developed. The tentacles are all broken short off; (pr.ap) apical pro-—
jection; (1) lip; (tra) radial tentacle; (cra) radial canal. From a pho

tograph.
Quadrant of bell margin of a slightly older specimen, 7 mm. high by 5 mm. in
diameter; (0) ocelli; (¢.c) circular canal.
Oral view of the same specimen, showing either one or two tentacles and
from two to four rudimentary tentacles between every two radial canals (cra) ;
(0) ocellus. .
Turris fontata, sp. nov., type.
Distal portion of radial canal (¢.ra), showing lateral glandular diverticula
and bell margin; (¢.c) circular canal; (t.ra) radial tentacle; (0) ocellus. Fro
a photograph. x 5.
Portion of bell margin with marginal organs; (t') large tentacle: (t? imma-
ture tentacle; (0) ocellus; (s) exumbral sense pit. x 15.
Longitudinal section through base of large tentacle, showing tentacular ostium (os)
by which its cavity communicates with the exterior ; (l.vas) vascular endoderm
lamella; (ec) ectoderm; (en) endoderm; (v) velum. x 30.
Side view of base of tentacle; (g) jelly; (s) exumbral sense pit; (¢.c) lumen of
circular canal; (v) velum. From a photograph. x 15.
Side view of margin of bell, and exumbral sense pit (s); (t) base of
tentacle. x 100.
Section through margin of bell and sense pit; (ec) ectodermic lining of sense
pit, with bristle cells. x 150.
Exumbral view of tentacle base, and sense pit (s); (os) tentacular ostium. x 20.

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MEDUSAE PLATE 42.

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PLATE 43.

All figures engraved from photographs.
Sibogita simulans, sp. nov., type. Apex of bell cavity in side view. The blind
termination of one of the adradial canals (c.ara) is clearly visible; (c.ra) radial
canal ; (go) gonad. x 4.
Sibogita simulans, portion of bell margin. There is one tentacle opposite every
canal; (e.ara) adradial canal ; (¢.c) circular canal; (t.ra) radial tentacle. x 6.
Amphinema turrida; one-half of bell margin showing the two well-developed radial
tentacles, and a large radial tentacular bulb. There are in addition two or three
rudimentary tentacular knobs in each quadrant. In this specimen none of the
latter bear filaments, but occasionally they do so; (c.ra) radial canal ; (0)
ocellus. x 12.

Cytaeis vulgaris, manubrium with medusa buds (b) ; (tl) labial tentacle. x about
20.

Cytaeis vulgaris, lip region; (tl) labial tentacle.

Stomotoca divisa; manubrium, to show crenulated lips (1) and gonads (go). xX 2.

Stomotoea divisa; one-half of bell margin, showing the two large radial tentacles
(t.ra), and numerous rudimentary tentacular knobs; (c.ra) radial canal.
xX 2.5.

Sarsia coccometra, sp. noy., tentacle, showing nematocyst ridges and terminal
nematocyst knob ; (0) ocellus; (¢.ra) radial canal.

Sarsia coccometra, Manubrium and apex of bell. The interradial ridges labelled

(go) are not the gonads, but merely folds of the gastric wall. (See p. 180.)

Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Fig. 7.
Fig. 8.
Fig. 9.
Fig. 10.
Fig. 11.
Fig. 12.

PLATE 44.

Zanclea gemmosa; portion of bell and tentacle (t); (c.ra) radial canal; (nem.r)
exumbral nematocyst rib; (nem) stalked tentacular enidoblast. x about 50.

Zanclea gemmosa; manubrium with large ova (ov). x 40.

Amphinema turrida; side view of an immature specimen. The gonads (go) have
not yet united with the subumbrella. From a preserved specimen. xX 25.

Amphinema turrida. Cross-section of manubrium near its base. The gonads
(go) are continuous in the interradii, but interrupted in the perradii; (c.ra)
radial canal ; (gas) gastric cavity. From a photograph. xX 25.

Bougainvillea fulva. Diagram of the dichotomous branching of one of the labial
tentacles.

Bougainvillea fulva. Side view of manubrium; lip (1) and labial tentacles (t.1)
with terminal nematocyst knobs (nem). From a photograph. x 25.

Bougainvillea fulva. Cluster of marginal tentacles, containing thirteen members;
(0) ocellus. From a photograph. x about 30.
Purena brownei. Tentacle, showing naked proximal portion, and distal portion
clothed with nematocyst ridges. From a photograph. xX 25.
Purena brownei, exumbral view of tentacle base; (0) ocellus. From a photo-
graph. xX 35.

Purena brownei, side view of tentacle base; (0) ocellus; (en) endodermic core
of tentacle. From a photograph. x 35.

Lymnorea alexandri, dissection of margin giving side view of tentacle base,
with ocellus (0) on its oral side; (¢.c) circular canal; (v) velum; (g) mesogloea.

Lymnorea alexandri, side view of apex of bell, showing manubrium, inter-
radial gonads (go) and labial tentacles or knobs (t.1); (¢.ra) radial canal.
From a preserved specimen. X 30.

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Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Fig. 7.
Fig. 8.
Fig. 9.
Fig. 10.
Fig. 11.
Fig. 12
Fig. 13.

Puate 45.

Pegantha triloba, exumbral view of a marginal lappet, showing form and
extent of otoporpae (otp), and position of otocysts (ote); (v) velum; (per)
perona. x 8.

Pegantha triloba, dissection of gonad, showing the sexual lobes (go) supported
by the gelatinous genital prominence (g.pr). x 10.

Cunina peregrina, sp. nov.(?) Stolon, taken from bell of a Rhopalonema velatum.
x 30.

Young medusa just liberated from above stolon, showing long manubrium (mn),
rudimentary tentacles (t), and otocysts (otc). x 50.

Oral view of somewhat older medusa, from the same stolon, in which there are
eight tentacles and well-developed otoporpae; (ote) otocyst; (mn) manubrium.
x 60.

Side view of same medusa, from a photograph, showing otocysts (otc); manu-

’ brium (mn); velum (v); tentacles; and outline of gastric cavity.

Two marginal lappets of same specimen, showing otoporpae (otp), and otocysts
(ote). There is no visible indication of a peripheral canal system (v), velum.

Cunina peregrina, sp. nov., otocyst; (otl) otolith; (otp) otoporpa. x 250.

Crossota brunnea, oral view of apex of bell, showing the long manubrium (mn),
gonads (go) hanging from the radial canals (¢.ra) into the bell cavity, and the
muscular condition of the subumbrella. x 5.

Amphogona apsteini, otocyst ; (en) endodermie core; (otl) otolith. x 100.

Rhopalonema velatum ; one octant of bell margin, showing arrangement of mar-

ginal organs; (t.ra) radial tentacle ; (otc) otocyst. x about 25.

. Colobonema sericeum; one octant of bell margin, showing the relative sizes of

radial (t.ra), adradial, and interradial tentacles, muscular condition of the
subumbrella, and extent of the gonads (go). From a photograph. x 4.

Halitrephes maasi, gen. nov., sp. noy. Portion of the bell margin of type
specimen, showing relation of radial canals (¢.ra), tentacles, and otocysts
(ote).

ALBATROSS EASTERN PAGIFIC EX MEDUSAE PLATE 45.

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13

B Moise! bas Boston

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— Puate 46.

a

PLATE 46.

Bathymetric chart of the route.
(For stations occupied see Plates 47 and 48.)

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BINDING SECT. JUN 6 1986

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