LIBRARY

OF THE

UNIVERSITY OF CALIFORNIA.

RECEIVED BY EXCHANGE

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ahs te aah
SS

Pate

ete DANISH

PN LPF EXPEDITION.

VOL. Ill a.

PUBLISHED AT THE COST OF THE GOVERNMENT
BY

THE DIRECTION OF THE ZOOLOGICAL MUSEUM OF THE UNIVERSITY.

COPENHAGEN.

H. HAGERUP.
PRINTED BY BIANCO LUNO AJs.

1899—I9I5.

Contents of Vol. III a.

I. Fr. Mernert: Pyenogonide, p. 1-71 (5 plates), 1899.

Il. H. J. Hansen: Crustacea Malacostraca, I: Decapoda, Euphausiacea, Mysidacea, p. 1-120
(5 plates), 1908.

Ill. H. J. Hansen: Crustacea Malacostraca, II: Tanaidacea, p. 1-145 (12 plates), 1913.
IV. C. Wir: Copepoda, I: Calanoidea. Amphascandria, p. 1-260 (8 plates), 1915.

THE DANISH

INGOLF-EXPEDITION.

VOL) TE PAR ECL

CONTENTS:

FR. MEINERT: PYCNOGONIDA.

PUBLISHED AT THE COST OF THE GOVERNMENT
BY

THE DIRECTION OF THE ZOOLOGICAL MUSEUM OF THE UNIVERSITY.

( Giiveneity
\Sauroawis :
COPENHAGEN.

H. HAGERUP.

BIANCO LUNO (F. DREYER), PRINTER TO THE COURT.

1899.

THE DANISH INGOLF-EXPEDITION.

VOLUME il.

4,

Pye OG O NI D-A,

BY

FR. MEINERT.

WITH 5 PLATES AND 2 FIGURES IN THE TEXT, 1 CHART, AND A LIST OF THE STATIONS.

% me: sSRA. RSX
Ene, OR THE oe t
UNIVERSITY

GF )

ALiFoRNS

TRANSLATED BY TORBEN LUNDBECK.

re

eee

—

COPENHAGEN,

BIANCO LUNO (F. DREYER), PRINTER TO THE COURT.

1899.

CONTENTS.

Pycnogonida.
Page Page
Introductory RM Mees SeSiai cs os. =o Yoru: elena aon veiw re Genn Palletie: (JOHOSE) 55) ooo od sere le alane 48.
Oa fo. on. bebo aha eLeaibrolie el piste te I. Pallene ABACUS MSPs ie) eo 6 ores ayy ww tno 48.
The History of Development .........-+-.+5- 5 sr SAS ERER (TDs BPitarie sie. ois) bose ee iaee 49.
Systematism, 5 os oe eles wel ie Glia te wie lees 31. Gen, Cordylochele:G,; O.- Sars) ei 5 \s, s)e es eee o's 50.
<. Ham, Nymphonides is vcs ete a sce aicdne sae abieye-'s >> 33. -- malleolata G. O. Sars...... 50.
2. Subfan:.. Nyniphoninis soe eo ee 34. — longicollis G. O. Sars...... 50.
Gene Nyntphon: (Faht:)s coos sit, 0 is eee ee ess 34. Gem, Peeudopallene Wils. 0). ios oF kw wes 50.
_ LORMIIES HADI si 050 6 ieee te es 35. -- cireularis Goods......... 50.
_ NuTone 0 lids (ol) SSR ae eae apa 36. RST PABEHODGIO. WB. ae! csce. 6 ee eye) 8 wlisiadie s 5I.
— Drevitarse: Kress ec 37- = PUUBIPES: SPs ATS ates g ene so 5I.
— Bercncam oc (Oy Sane 6 o.0 oie 6 5:50 37- — fluminensis Kr. .......... 2 52:
—_ megalops G. O. Sars ........ 37. Pests) MBCOMMYTEMOGS: 5 aict oe etsy 82506 2 elalaieneie 0s 54.
SERED AN, Ns Si Nia 6 Sh wees ni 8, Goo 38. Gen. Ascorhynchus G. 0. Sars ...........- 55.
—- PORTE Me BO Ria oe phon he ai cites aie 39. — Sd ens THs Spin i) ate Gooey 55:
- PSERMPORNE Set pe Meg cis cans wire). %e PE OO 8 eC ales) Poe rs (as I a Pana 56.
— Loui to a 3S SS eee ena ea a 4I. Reeth, COIMBEENGEIS JAZ. os 3 ee goes egliee ete: a 57-
_ Groenlandicum n.sp......... 41. _ proboscidea. Sab... 5)... 2:- 57:
— Co a2 2 Yee a ga aS 42. _ CURVE TE SRA a (ss erat ones ea 57:
- leptocheles G. O. Sars........ 43. _ GOlKsea: WHE 6.5 50s orn ecaia, oe 58.
_ WMOCVIUI WU. Soma ie rsp ats a5 68s, 43- — angusta G. O. Sars........ 59.
_ macronyx G. O. Sars........ 43- —_ miacerrima Wils:..6..... 2s... 60.
_ Spinomuni: Goods: ssi. 6 ee see UG SG Ng Ea Bal 2 le ari Se 60.
-- tenellum G. O. Sars......... 45. Sa TUL ECMO VOUIOE. acre Ahem x iho). open e+ Reus 60.
_ PORE EI seo ale lar sok es 45. Gen Pyenoeoniin: (Oris) oc siecy et as eres os) nates 60.
Gon. Paranymiphon Cane ses vie ak as 46. — crassirostre G. O. Sars ..... 61.
= spinosum Caull. ........ OW tate OR UP MCOTACURS 93s usu hie cosea: oo asach Usee-aiy lew bye) sc hoalons 62.
NERS PAU ORIIED 5) ge fate ore sal 5) Boao Jo! ore ay ol Mr ee RUATION OF TG PIStes ous aso 6es eas ote ie atatets 08 65.

166040

-IBRAR

ae OF mrs

UNIVERSITY
OF

Pycnogonida.

By

Fr. Meinert.

he species represented in the following treatise have, with the exception of one only, been all
ea taken on the «Ingolf»-expedition. The said one species is Pallenopsis fluminensis Kr., which
has been included in order to elucidate the genus, and throw light on this much disputed species, the
original of which is still found at the Zoological Museum. The material for the «developmental
history» has likewise mostly been taken on the said expedition, although some few species have been
taken from earlier collections. The number of species taken on the «Ingolf»-expedition is 31, of
which 8 are new to science. When 43 species are drawn and described by G. O. Sars in «Den norske
Nordhavs-Expedition, 1876—78», it is to be remembered that only 20 out of these 43 species are due
to the collections of the expedition.

Terminology.

Although the terminology of a group of animals chiefly depends on the systematic position
of the group, and the homologies and analogies founded on this position, on the other hand it will
be necessary to begin with definite appellations for each of the organs, though these appellations can
only be justified by the later examination and the systematic position founded thereon. I therefore
shall begin with giving a list of the names I have chosen; and as I here chiefly follow the appella-
tions given by Sars, so I also take the liberty to copy his figure, Pycnogonidea, 1891, p.3, which
will be found on the other side.

From the two lists it will immediately be seen that I have not thought myself justified in
following Dohrn, when he, more particularly after Savigny, gives to the limbs a continuous
numerical order, Extremitas I—VII. This way of designing the limbs has several advantages, and
has also been followed by later authors, as Adlerz and Schimkéwitsch, but it has also important
defects, which make themselves strongly felt. It is an advantage of the terminology of Dohrn that
it is independent of all systematism; to this terminology it is all the same, whether the Pycnogonida
are Crustacea or Arachnida; it has not to be altered to-day, that to-morrow, when another systematic
taste is ruling, it may return to the expressions of yesterday, more or less altered in the interval. It
is, however, inconvenient, when one or more of the seven pairs of limbs (extremities) are specially

The Ingolf-Expedition. IIL 1. I

2 PYCNOGONIDA.

characteristic in contradistinction to the others, or when one or more pairs have disappeared, so that
«Extrem. IV» is to be understood, now as the first, now as the second, third, or fourth pair of the
Preserved limbs of the imago. The greatest drawback by Dohrn’s way of designation is to me that
it does not at all agree with the developmental history, the embryonal legs (fig.2 6, c) not being
included; and although they are not to be regarded as the predecessors of the two foremost pairs of
ambulatory legs (Kroyer), they are neither the predecessors of the second and third typical pairs of
limbs of the imago, the imaginal fore-limbs, or of the palpi and the ovigerous legs. I hope that it
will appear from my examination of the larval development that these two pairs of limbs are not
predecessors of, or identical with, the embryonal legs, to which examination the reader is referred.
Now, if the embryonal legs are neither identical with the two first pairs of ambulatory legs (Kroyer),
nor with the palpi and ovigerous legs (Dohrn’s Extrem. II and III), there will be typically 9, and
not 7, pairs of limbs, as supposed by Dohrn and all naturalists, excepting Semper, Pycnog. und
Larvenf., 1874 (who has 8 pairs). Even if it be supposed that the embryonal legs are peculiar limbs,
it would, of course, be possible to use the appellation of Dohrn, the list of limbs then only being
increased from VII to IX; but on the other hand it would be very untoward to be always obliged to

subtract several, sometimes more than the half, from the number, which is got by adding the embry-

¥ Proboscis (rostrum).
PR ct, First segment of trunk (segmentum corporis primum).
0. Oculiferous tubercle (tuber oculare).

cl. Neck (collum).

apo. lateral process of the first segment for the insertion
of the ovigerous legs (protuberantia pedis oviferi).

ce, Second segment of trunk (segmentum corporis secun-
dum).

3. Third segment of trunk (segmentum corporis’ tertium),

C4. Fourth segment of trunk (segmentum corporis quar-
tum).

Se. Caudal segment (segmentum caudale).

pel. Lateral process of the body for the insertion of the
ambulatory legs (processus corporis lateralis).

chf. Cheliforus (cheliforus).

S. Scape (scapus).

ch. Chela, or Hand (chela vy. manus).

plm. Palm (palma).

dim. Ummovable finger (acumen y. digitus immobilis).

dm. Movable finger (pollex v. digitus mobilis).

pa. Ambulatory legs (pes ambulatorius).

ext, First coxal joint (articulus coxalis primus).

cx2, Second coxal joint (articulus coxalis secundus).

cx3, Third coxal joint (articulus coxalis tertius). ey

te Femoral joint (femur). fi

7x. ‘First tibial joint (articulus tibialis prior).

#2, Second tibial joint (articulus tibialis alter).

tat, First tarsal joint (articulus tarsalis prior).

ta, Second tarsal joint (articulus tarsalis alter).

ut. Claw (unguis).

uo. Auxiliary claw (unguiculus auxiliaris).

plp. Palpus (palpus v. pes palpiformis).

po. Ovigerous leg (pes ovifer).

z pir. Terminal part of the ovigerous leg (pars terminalis
Fig. 1. Mymphon Stroemit. 3 pedis oviferi).
glov. Egg-globe (globus ovorum).

PYCNOGONIDA.

onal legs to the pairs of limbs found in the imago. In the genus Pycnogonum the first pair of ambu-
latory legs, according to this, would be called Extrem. VI, the first five pairs of limbs having to be
subtracted. .

The foregoing list and figure apply to the grown larva, the young, and the imago; with
regard to the young larva the following short list together with the figure of this larva, seen from

the under side, must suffice.

Cheliforus.

First pair of embryonal legs.
Second pair of embryonal legs.
Proboscis.

First pair of ambulatory legs.
Second pair of ambulatory legs.

4S APLAR

Fig. 2. Nymphon robustum. Warva.

I shall now proceed to notice the outer organs, giving a short description of each as well as
the reason of the terms I have chosen, and at the same time I shall quote as synonyms the corre-
sponding appellations by the chief earlier authors.

Proboscis (rostrum), fig.1 7, and 2 d.

O. Fabricius: tubulus v. rostrum; Latreille: tuyau ou siphon dune seule piéce; later (Régn.
anim. éd. II): bouche; Leach: os tubulosum, or rostrum; Savigny: premier anneau du corps allongé
et remplacant la téte (vestiges de machoires); Johnston: rostrum; Milne-Edwards: téte; Erich-
son: Zunge; Kroyer: Neb (in the larva), later: Snabel (rostrum); Wilson: proboscis, or rostrum;
Dohrn: Schnabel; BGhm: Rostrum; Hoek: trompe (proboscis); Adlerz: snabel; Hansen: Snabel,
or Proboscis (proboscis); Sars: Snabel (proboscis), or Mundsegment.

The proboscis is the conical or almost cylindrical organ protruding from the anterior margin
of the body, or from the lower side of it; it is always large or especially so in proportion to the body,
and has at the point a trilobate mouth, leading to the trilateral pipe, which is closed behind by a
kind of plait, protruding to a rather sharp angle and working as a filtering apparatus. The pro-
boscis is commenced at a very early stage of the embryonal life (pl.1, fig.1) as a ball or tubercle
without any trace of mouth, contemporary with the embryonal limbs (the chelifori and embryonal
legs). It is no segment or metamere, and still less corresponding to, what in other animals is called
the head, or to part of the head. Neither can it in any way be supposed to have arisen by a coal-
escing of gnathites.

First segment of trunk (segmentum corporis primum), fig.1 c.

O. Fabricius: caput et thorax v. primus articulus corporis; Leach: segmentum anticum;
Latreille (Régn. an. éd. II): le premier segment du tronc; Johnston: the anterior segment of
thorax; Erichson: Kopf; Kroyer: Qiering og forste Brystring (annulus ocularis et annulus thora-

{*

4 PYCNOGONIDA.

cicus primus); Wilson: oculiferous segment; Dohrn: das erste Rumpfsegment; Bohm: Augenring;
Hoek: cephalothorax; Adlerz: cephalothorax; Hansen: forste Kropring; Sars: Hovedsegment (seg-
mentum cephalicum).

The first segment, when viewed from above, presents a simple surface without any trace of
composition or articulation, and Kroyer, when he nevertheless divides it into an ocular segment and
a first segment of thorax, has not been able to point out any trace of a cross-seam or any other arti-
culation, but has evidently started from the a priori reason that eyes cannot be found on a thoracic
part (cp. the following). If the animal, however, is seen from before, several seams or lines may some-
times be seen more or less distinctly, as marking the boundary of peculiar skeletal parts, originally”
independent, but now united with the first segment of the thorax. Thus under the fore-edge of the
first segment of the trunk in Padlenopsis plumipes the common skeletal part (metamere) of the cheli-
fori may be seen as a transverse band (pl. IV, fig. 3). —- To understand the first segment of the trunk,
it is quite necessary to follow the larval development from the embryo. It will then be seen that the
first and foremost chief part of the embryo is formed by the proboscis and the three pairs of embry-
onal limbs surrounding this latter, while the other chief part is not developed till later, the ambula-
tory legs and the four segments of the trunk together with the caudal segment not being partitioned
off at first. The first chief part, most frequently with the exception of the chelifori, shrinks by and
by, loses its independence of the other chief part, and is, as it were, swallowed up by the foremost
part of this latter, the first segment of the trunk; not until this has taken place, and the embryonal
legs have fallen off, do the imaginal fore-limbs, palpi and ovigerous legs, spring forth on the lower
side of this segment, when they are developed at all. The further details of this growth will be
found in the following in the section treating of the larval development.

If we suppose that the four segments with the ambulatory legs of the Pycnogonida correspond
with the thorax of the other Arthropoda, especially with that of the Arachnida and Insects, and the
first principal segment of the embryo with its three pairs of limbs likewise corresponding with the
head of those animals, the name of Cephalothorax (Hoek, Adlerz) for the first segment of the
trunk would be very good; but as I consider this comparison as wrong, or, at all events, as inde-
monstrable, I shall prefer another, less marked appellation, and as such I consider the one I have
chosen. I, for my part, think it to be most probable, or at all events possible, that the second princi-
pal segment of the Pycnogonida with its four pairs of ambulatory legs and the caudal segment can
be compared with the abdomen of the Arachnida, in which this part in its development has, or may
have a similar division into somites, and similar rudimentary limbs as in the Pycnogonida, cp. Locy:
Developm. Agelena, 1885, pl. II, fig. q—11, and pl. III, fig. 13—15. The position of the genitals then
would also, as generally is the case, be in the abdomen, and in the processes of the abdomen, that is,
the ambulatory legs. On the other hand, the eyes would be placed on the fore edge of the abdomen,
but eyes (and peduncles in the pedunculated Crustacea) do not form a typical part of the body in
any auimal, belonging to or constituting the head; and even if we, to avoid this difficulty, should call
the part of the body, in which the eyes are placed, cephalothorax, it is still in the hindmost part of
this segment, in the thorax, or the. first somite of it that the eyes would be placed — and farther

forward, to the head itself, they would never come.

PYCNOGONIDA. 5

The <oculiferous segment» of Wilson and the «Augensegment» of Bohm is only another
expression taken from the appellation of Kroyer, but applied to the whole of the first segment of
the trunk. When Erichson uses the name of Kopf for this part of the body, it is exclusively with
regard to the ambulatory legs and the comparing them to the limbs of the Arachnida, of which again
the three last pairs were to correspond to the thoracical legs of the Insects, while all the correspond-
ing segments were to form the thorax.

Oculiferous tubercle (tuber oculare), fig. I, o.

Kroyer: @Mieknude (protuberantia ocularis); Sars: Oieknude (tuberculum oculiferum).

On the dorsal side of the first segment of the trunk, in the middle of it, but more or less
backward, is found a knob-like protuberance, the oculiferous tubercle. The shape of this knob is very
different, varying in the different genera and species, growing from a low, rounded swelling to a
height of almost the length of the trunk, and ending with a tapering point. It is not until the second
larval stage of development that the oculiferous tubercle begins to be seen as an excrescence on the
first segment of the trunk after this segment being distinctly separated. The eyes make their
appearance prior to the oculiferous tubercle on the spot of the first segment of the
trunk, from which this latter rises, and during the growth of the tubercle the eyes are raised with
it more or less, so that in the imago they are placed in a square round the tubercle, more or less distant
from its top. The tubercle bears typically four single eyes, ocelli, but frequently the eyes are not, or
only a little, developed, so that as well blind species as seeing ones may be found in the same genus
(Colossendets).

Neck (collum), fig. I e/.

I have thought it best, like Sars, to keep this name for the middle part of the first thoracical
segment, when it is more or less strongly marked off, as I regard this appellation as so little marked,
that it is no necessary consequence to look upon or denominate as head the thickened part of the
trunk lying before the segment in question.

Lateral process of the first segment for the insertion of the ovigerous legs
(protuberantia pedis ovifert), fig. 1 apo.

Sars: Halsfortsats (processus colli) til Feeste for de falske Fodder.

This process originates from the under side of the first segment of the trunk just before the
process ‘of the trunk; it is very short, inconspicuous, and from its outer side or point arises the
ovigerous leg. When the segment of the trunk is short, so that there is no neck, the palpi get
towards it, and in some genera (Colossendeis) the palpi do apparently arise from the fore side of
this process.

Second segment of trunk (segmentum corporis secundum), fig. 1 c?.

Third segment of trunk (segmentum corporis tertium), fig. 1 c.

Fourth segment of trunk (segmentum corporis quartum), fig. 1 ct.

No synonyms are here necessary to explain the opinion of the authors as to these segments.
It is a matter of course, and everybody agrees that they are homonomous with the first segment of
trunk, or, at all events, with the large upper and hinder part of it.

Caudal segment (segmentum caudale), fig. 1 sc.

6 PYCNOGONIDA.

Linné: cauda; O. Fabricius: cauda; Latreille: le dernier segment du corps; Lamarck:
abdomen; Leach: abdomen; Savigny: abdomen; Johnston: abdomen; Milne-Edvards: abdomen;
Erichson: Hinterleib; Kroyer: Bagkrop, abdomen; Wilson: abdomen; Dohrn: Hinterleib;
Bohm: Abdomen; Hoek: abdomen; Adlerz: abdomen; Hansen: Bagkrop (abdomen); Sars: Hale-
segment (segmentum caudale).

The appellation of this part of the trunk was in the early authors (Linné and O. Fabricius)
simply cauda, tail; but Latreille having pointed out that it was a part, a segment, of the trunk
itself, the first name was displaced by the appellation abdomen and the translations of it (Hinterleib,
Bagkrop), which was adopted by all authors until Sars, the opinion being, I suppose, that it corre-
sponded to the abdomen of the other Arthropoda, especially that of the Insects and the Arachnida.
Sars, as it were, has meant to adopt the old name of tail, but on account of the prevalent aversion
to this appellation, he has altered it to the mediate one of caudal segment, and I have followed him
partly of similar reasons. — As to its development the caudal segment is the hindmost part of the
hindmost principal division of the embryo, and until a far advanced stage in the larval development
it forms a hindmost, gradually more protruding, process of the fourth segment of trunk. If upon the
whole it is separated from this segment by a dermal suture, this does not take place until the third
larval stage. It never bears limbs, but the intestinal canal opens in the end of it with a weak squir-
ting apparatus. Thus the caudal segment no doubt belongs to and makes the hindmost
part or segment of the same principal portion to which the four preceding segments
belongs; it is no separate part of the body, different from the foregoing segments of the trunk, no
abdomen in contradistinction to a thoracical part, lying before it. The caudal segment can be pro-
portionally very long, almost as long as the body, and then it is also well separated from the fourth
segment of the trunk and very slender; there is no trace of division in joints, not even in Zefes
(Zurycyde), as has been maintained. On the other hand this segment may also be quite small, as it
were, rudimentary, as I know from a not described genus among the collections, which the Smithsonian
Institute has given me for examination.

Lateral process of the body for the insertion of the ambulatory legs (processus
corports lateralis), fig. 1 pel.

Sars: Legemets Sidefortsatser (processus laterales corporis) til Faeste for Gangfodderne.

These processes of the body and the ambulatory legs attached to them, are structures charac-
teristic of the Pycnogonida, as they are not formed by germinating or growth of a particular cellular
group but, as is distinctly seen from my drawings of the embryo, by a bag-like constriction of the
ectoderm, in the same manner as the embryonal limbs (the chelifori and embryonal legs). They are
in reality only parts of the body, and ‘so it will easily be understood, that the intestinal canal and
the sexual glands can continue far into the ambulatory legs as processes of the body.

Cheliforus (cheliforus), fig.1 chf and 2a.

Linné: palpi; O. Fabricius: palpi; Latreille: mandibules; later (Régn.an. éd. II): antenne-
pinces; Leach: mandibule; Savigny: pedes secundi; Lamarck: antennules; Johnston: mandib-
les; Milne-Edwards: pattes-machoires; Erichson: erstes Kieferpaar or Scherenkiefer (Mandibeln);

Kroyer: Saxe (antenne cheliformes); later Kindbakker (mandibule); Bohm: Kieferfiihler; Wilson:

PYCNOGONIDA. Vi

antenne; Hoek: mandibules; Hansen: Kindbakkeantenner (antennz mandibulares, also mandibule) ;
Morgan: cheliceree; Sars: Saxlemmer (chelifori).

The chelifori are the foremost of the three pairs of embryonal limbs, and in most Pycnogonida
they grow on, and are kept to the stage of the imago. Only rarely they are thrown off during one
of the larval stages (fam. Phoxichilide — in Pycnogonum already on the second larval stage, pl. I,
fig. 4), or by the last casting of the skin in the young (Colossendets angusta and gracilis). They are
often more or less rudimentary, especially in the outermost joints (Ascorhynchide). Their resemblance
to the first pair of limbs in the Arachnida is conspicuous, and there can be no doubt of their impor-
tance with regard to the systematism. This consideration has also asserted itself in the appellations,
used for these limbs by most authors, and when nevertheless these appellations are so different, the
reason may be sought in the fact that also the foremost limbs of the Arachnida have very different
names; but as I think the names of antenna, mandible, or mandible-antenna in the Arachnida to be
equally objectionable, I have preferred partly after Kroyer, and together with Sars to use the ap-
pellation of cheliforus for the whole limb.

Scape (scapus), fig. 1 s.

Kroyer: Grundled (articulus basalis); Sars: Skaftet (scapus).

The cheliforus is divided into two chief parts, a basal or advancing part, and a terminal or pre-
hensile part. Of these the former sometimes is undivided, sometimes bipartite. The bipartition is
generally distinctly shown by a suture and by muscles, and but rarely it is only more or less indi-
cated, so that it may be doubted whether the scape has one or two joints (Padlenopsis).

Chela or hand (chela), fig. 1 ch.

Kroyer: Sax (chela); Hansen: Tang or Sax (chela); Sars: Sax (chela).

By the appellation chela or hand is designated the second chief part of the cheliforus, and it
will, on account of the systematism, be necessary to give special names to the separate parts. I have
supplemented the appellation by Kroyer and Sars of the second chief part of the cheliforus by the
expression «hand», because the separate parts, of which it consists, are named with appellations from
the hand. The chela or hand is the two outermost joints of the cheliforus, the first of which forms
a proportionally broad part, sending out laterally a long tooth- or finger-shaped process, which towards
the point meets with the point of the movable last joint. The hand may be more or less rudimen-
tary, or even wholly disappear.

Palm (palma), fig. 1 plm.

Kroyer: Palmen (palma); Hansen: manus; Sars: Palmen (palma).

Immovable finger (acumen v. digitus immobilis), fig. 1 dim.

O. Fabricius: acumen; Kroyer: ubevegelig Finger (digitus immobilis); Hoek: griffe immo-
bile des mandibules; Bohm: der unbewegliche Finger; Hansen: pollex; Sars: den ubevegelige
Finger (pollex).

O. Fabricius already felt impelled to distinguish between the immovable finger of the hand
and the movable outer joint of the cheliforus, and called the former acumen, instead of which expres-

sion Kroyer used immovable finger (digitus immobilis); Sars and Hansen, I think after him,

8 PYCNOGONIDA.

next introduced the expression pollex (i.e. thumb) for this process, though this latter name had already
been used by O. Fabricius and Kroyer of the last joint of the cheliforus, the movable finger.

Movable finger (follex v. digitus mobilis), fig. 1 dm.

O. Fabricius: pollex; Kroyer: Tommel (pollex); Hoek: griffe mobile des mandibules;
Wilson: dactylus; Bohm: Scheerenfinger or Daumen; Hansen: Index; Sars: bevegelige Finger
(dactylus).

I have kept the old name of O. Fabricius and Kroyer pollex or movable finger for the
terminal joint of the cheliforus, or the movable finger of the hand, and can see no reason to intro-
duce instead of it the dactylus of Wilson.

To avoid every misconception it would perhaps be best to omit the use of the short names of
pollex, dactylus, index, and thumb, and to abide by the appellations digitus immobilis and digitus
mobilis, immovable and movable finger, as I have done in the synoptical figure by choosing the
letters dim and dm.

Ambulatory leg (Jes ambulatorius), fig. fa and 2 ef

Schimkéwitsch, Pantop. «Vettor Pisani», gives to the first pair of ambulatory legs also the
separate name: Patte-machoire.

The rise and development of the four pairs of ambulatory legs follow the larval development,
and they are never wanting in the imago, nor reduced in any way but at most by the defective devel-
opment or the falling off of the claws or the auxiliary claws. They arise from the ends of the lateral
processes of the body, and are, to judge from the rudiments in the embryo and the larva, as has been
mentioned, only prolongations of these processes, constricted into the number of nine joints, inclusive
of the claw, which is common to all Pycnogonida.

First coxal joint (articulus coxalis primus), fig. 1 ct.

Second coxal joint (articulus coxalis secundus), fig. 1 c*.

Third coxal joint (articulus coxalis tertius), fig. 1 c3.

Sars: 3 Hofteled (articuli coxales).

These three joints form the proximal end of the ambulatory leg; they belong to the shortest
joints of the leg, and form a series of homonomous joints, being of one set; therefore they may all
together correctly be termed the coxa.

Femoral joint (femur), fig. 1 f

Sars: Laarled (articulus femoralis).

In the Arthropoda, especially the Insects, the femoral joint follows upon the coxa and coxal
segment or trochanter, which in these animals is only a subordinate joint. I think it, however, im-
possible to transfer the terminology of the legs of the Insects to those of the Pycnogonida, and there-
fore I have considered it advisable to follow Sars in his appellations of the joints of the leg, only
with some variation in the special names.

First tibial joint (articulus tibialis prior), fig. 1 tb.

Second tibial joint (articulus tibials alter), fig. 1 tb.

Sars: Legled (articuli tibiales).

These two joints of the leg are closely united, and there is no reason to give any prominence

PYCNOGONIDA. 9

to either of them, and so I agree with Sars in not using unnecessary appellations, taken from the
Arachnida or other Arthropoda. There is thus no reason to call one of the joints patella.

First tarsal joint (articulus tarsalis prior), fig. 1 tat.

Sars: Tarsalled (tarsus).

Second tarsal joint (erticulus tarsalis alter), fig. 1 ta’.

Sars: Fodled (propodus).

These two tarsal joints are closely united like the two tibial joints; often they are almost
uniform without any particular difference as to length or structure. If there is any difference, it con-
sists most frequently in the first joint being shortened, often much shortened in contrast to the second
one. If we should choose to distinguish between the joints, and give each of them a separate name,
I think that appellations as metatarsus and tarsus would be proper; but to avoid too many names
and all confusion with the appellations of Sars, I have only numbered the joints. The names given
by Sars, seem to me to be too unfortunate at all events; the name of tarsus meaning always the
outermost joint, or — if the tarsus is divided — joints of the leg.

Claw (wnguzs), fig. 1 2.

Sars: Endeklo (unguis terminalis).

The claw, as mentioned above, is only the last terminal joint of the leg (corresponding to the
claw in the larva of the Staphylinids and of most Coleoptera), but is not included in the foot. It
is very much varying as to shape and size, often in the same genus (for inst. in Colossendezts); as it
cannot be mistaken for any other claw, I have thought it unnecessary to use a more particular
appellation.

Auxiliary Claws (unguiculi auxiliares), fig. 1 ua.

Sars: Bikloer (unguiculi auxiliarii),

These auxiliary claws are really the terminal claws of the foot, originating from and attached to
the last joint (the claw) of the foot. In so far they are real claws, and correspond to the claws in the
Arachnida and most Insects. Corresponding claws are wanting in the Crustacea, and therefore their
presence in the Pycnogonida is of no small systematic importance; it is to be remarked, however, that
they often become rudimentary or quite disappear, but nevertheless they may be said to be typical in
this group of animals. As to their importance in assisting the claw, it evidently cannot be great, and
therefore their Latin name of auxiliares or auxiliarii is not very appropriate.

Palp (palpus v. pes palpiformis), fig. 1 pip.

Linné: antenne; O. Fabricius: antenne; Latreille: palpes; Leach: palpi; Savigny:
pedes tertii; Lamarck: antennules; Johnston: palpi; Milne-Edwards: palpes; Erichson: zweites
Kieferpaar, Maxillen, Tasten; Kroyer: Palper; later: first pair of jaws or Maxiller (maxilla primi
paris); Wilson: palpi; Bohm: Palpen; Hoek: palpes; Hansen: Palper; Sars: Foler (palpi).

After Latreille, more particularly, perhaps, founded on his theory of the proboscis being
formed by a composition of gnathites, having introduced the appellation palpes for the word antenna
used by Linné, this name (palpi—palpes) has now been used by almost all later authors; some
(Erichson, Kroyer) have thought, however, that this pair of limbs do not correspond to the
palps of the other Arthropoda only, but to the whole corresponding pair of gnathites, and have named

The Ingolf-Expedition, IIL 1. 2

10 PYCNOGONIDA.

it according to this opinion (Kiefer, Maxiller), In Dohrn, Adlerz and Schimkéwitsch it of
course becomes Extrem. II. As I, as well as Dohrn, reject the theory of Latreille, I have retained
the name of palps.

The palps are the first pair of the imaginal fore limbs; they do not arise, until the embryonal
legs have been thrown off, and have no continuous connection with the latter. They always originate
from the anterior edge of the lower side of the first segment of the trunk, often at a great distance
from the ovigerous legs; but when the segment is shortened they approach the ovigerous legs, even
so far as to apparently originating from the lateral process, on which those legs are inserted (Co/os-
sendeis), It is to be supposed that they are of no great importance in the life of the animal, and
they also form the pair of imaginal limbs, which are liable to the greatest changes as to length, number
of joints etc, and soonest become rudimentary or are thrown off. In Ascorhynchus tridens 1 have in
the fourth joint of these limbs found a particular organ of sense (?); as to details see the following -
section on the ovigerous legs.

Ovigerous leg (pes ovifer), fig. 1 po.

Linné: tentacula pectoris; O. Fabricius: pedes spurii (fila ovifera); Latreille: pattes; later
(Régn. an. éd. II): fausses pattes; Leach: organa ovifera; Savigny: pedes quarti; Johnston: ovife-
rous legs; Milne-Edwards: appendices pediformes; Erichson: drittes Kieferpaar; Kroyer: andet
Par Kjeeber, A7ggetraad; Wilson: accessory legs; Bohm: Hitrager; Hoek: pattes oviféres; Hansen:
pedes ovigeri; Sars: falske Fodder (pedes spurii).

The most common appellations of this second pair of imaginal fore limbs are owing to the
fact that they are used for carrying the eggs. Another starting point may he found in the peculiar
position of these limbs, as seemingly they can be classed neither among the gnathites nor among the
ambulatory legs, a fact already pointed out by O. Fabricius.

The ovigerous legs are the latest developed limbs, even if their development takes place only
a little later than that of the palps. They arise on a level with and behind the palps on a particular
process, but their position in relation to the palps, especially with regard to distance, has already been
mentioned. They are of a more considerable length and most frequently have more joints than the palps.
The number of joints is typically ten, exclusive of the claw, that is to say, one more than the number
we arrive at in the ambulatory legs, when in these we count the claw as a joint, and consider the
auxiliary claws as corresponding to the claw of the ovigerous legs. Their most important function is
in the male to carry the eggs, for which purpose some of the joints are often thickened or provided
with particular hair-formations especially in the male. Besides I have in different species of Nym-
phonide (Nymphon groenlandicum n.sp. pl. Ill, fig.20@; Pallene hastata un. sp. pl. IV, fig. 17 @) and as
well in the male as in the female, found in the fourth joint of these limbs an inner organ consisting
of a lengthened bag, divided, as it were, into two parts by a constriction in the middle; this bag is
by long ligaments of connective tissue, arising from its anterior and posterior end, attached to the
exoskeleton; a broad nerve runs along the longitudinal side of the bag. No doubt this bag is an
organ of sense, I suppose, of hearing. In the Ascorhynchus quite a similar organ is found, only that
in this animal it is not found in the ovigerous legs, but in the palps (cp. above). But besides ser-

ving as bearers of the eggs in the male and bearers of an organ of sense, they serve, as I suppose,

PYCNOGONIDA. it

in both sexes as combs or cleansing apparatus for the other limbs of the animal, all of which can
presumably be brought within the sphere of action of the rows of dermal leaves‘) (the comb) with
which the last joints of the ovigerous legs are provided.

The terminal part of the ovigerous leg (Pars terminalis pedis ovifert), fig. 1 ptr.

Sars: Endeled (pars terminalis).

I have, as Sars, given a special name to these four last joints of the ovigerous leg, bearing
the comb or cleansing apparatus, just mentioned. The comb consists of a greater or lesser number
of daggershaped dermal leaves with deeply incised edges, arising in one or more rows from the inner
side of these four joints. The claw, with which the leg terminates, is closely joined to the comb, and
as it is often deeply incised in its inner edge it also partakes in the work of the comb.

The egg-globe (globus ovorum), fig. 1 glov.

Sars: A¥ggeklump (globa ovorum).

The male, as it is well known, (Cavanna, Studi Picnog., 1877) carries the deposited eggs,
placed in lumps around one or more of the middle joints of the ovigerous legs. As the size of the
eggs is very different in the different Pycnogonida, so it is also with that of the lumps, but most
frequently the size of the lumps and of the eggs stands in an inverse ratio to each other. As a rare
exception the males of some species carry the eggs in one cake on the lower side of the body (Pyc-
nogonum), while the males of other species have some few, very large eggs attached singly to the
ovigerous legs (Pallene). The number of egg-globes most frequently is two, one globe on each of the
two legs, but frequently this number is doubled or increases further to 4—5 globes on each leg. Very
rarely only one leg has one single egg-globe; I have, however, found this to be the case in by far
the most of the males of Nymphon robustum, that I have had for examination.

The preceding survey of the limbs and parts of the body of the Pycnogonida applies also to
the young larve, in so far as those limbs and parts have been developed; but besides these larvee
have particular limbs, and to show these limbs I have on p.3 given a contour-drawing of such a
larva, fig. 2. Especially are to be mentioned:

Embryonal leg of the first pair (Pes embryonalis prioris paris), fig. 2 6.

Embryonal leg of the second pair (Pes embryonalis alterius parts), fig.2 ¢.

These two pairs of limbs develop at the same time as the chelifori (or the first pair of embry-
onal legs) and the proboscis on the first chief part of the embryo; they soon attain to their full devel-
opment, but are also early thrown off during the second or third larval stage. Only rarely they are
not developed at all (Pallene hastata, pl.1, fig. 18-19) or grow only to short, tap-like processes (Pseu-
dopallene spinipes, pl.I, fig. 8, and Pseud. circularts, fig. 10, as well as Pallene brevirostris, fig. 16).

The History of Development.
On the development of the Pycnogonida there exists a rather considerable literature. The

attention must first be drawn to the fact that the common distinction, also used in this work, which

1) By Sars these leaves or blades are rather unluckily named «Randtorners, in English «marginal spines».

2*

12 PYCNOGONIDA.

is made between the embryonal and the larval stage, cannot be fully kept up with regard to the
development of the Pycnogonida. The general mark of distinction (whether the embryo has or has
not left the egg) is here of only very little importance, and nearly related forms, even species of the
same genus, may attain to a different, sometimes very different development in the egg. Accordingly
it will not do to deny the metamorphosis in such forms as do not leave the egg until they have
attained their permanent shape. This opinion and the interpretation of the larval development now
generally current have been expressed by Korschelt a. Heider (1890) p. 662 seq: «Die meisten
Pantopoden entwickeln sich mittelst Metamorphose. Ihre Larven weisen gewOdhnlich drei Extremi-
tatenpaare auf, doch verlassen einige in héherer Ausbildung das Ei; so besitzen die jungen Pallenen?’)
beim Ausschliipfen bereits sdimmtliche Extremitaiten und auch einige Arten der Gattung Nymphon
erreichen schon im Ei diese héhere Entwickelungsstufe. Die verschiedenen Arten der letztgenannten
Gattung differiren tibrigens in dieser Beziehung, da die Larven einiger beim Ausschliipfen nur vier
oder fiinf Extremitaétenpaare aufweisen (Hoek).» As will be seen from this quotation, Korschelt and
Heider found their statement especially on the examinations by Hoek, or recapitulate the principal
contents of the description of Hoek as it is given in his last great work: «Nouvelles études sur les
Pycnogonides» (1881), p. 482 seq.

But before I pass to my own representation of the developmental history I shall give a short
historical view of the most important works in this branch of study, and as we have already in
Dohrn: «Die Pantopoden des Golfes von Neapel» (1881) a very copious literary survey, I may limit
myself to the following four authors: Kroyer, Dohrn, Hoek and Morgan.

Kroyer is the author to be named first, not only because he first of all has studied and de-
scribed larvee of the Pycnogonida, but also on account of his contributions being the most important
ones we hitherto have got concerning the development of these animals. Already his «Om Pycnogo- .
nidernes Forvandlinger» («On the metamorphoses of the Pycnogonida») (1840) is of great importance,
but still more so is the series of representations of larval forms given on pl. 39 of the great, unfinished
French work of travel: «Gaimard, Voyages en Scandinavie» etc. (1849) to which never appeared
any text or explanation. As such an explanation may with regard to the Pycnogonida be taken
Kroyer’s «Contributions to our knowledge of the Pycnogonida», «Bidrag til Kundskab om Pycnogo-
niderne eller Sospindlerne» (1845). In the close of the third section of this treatise, on the metamor-
phoses of the Pycnogonida, l.c. p.136 seq. Kroyer collects the laws that seem to regulate the devel-
opment of the Pycnogonida under 5 principal heads which may briefly be rendered thus: 1° The
Pycnogonida pass through 3 stages. 2° The first stage is of a thick, swollen shape; filled with yolk
substance; without any abdomen; with a proboscis; with cheliferous «Kindbakker» (mandibles);
and with 2 pairs of feet. Eyes seem to be wanting. 3° In the second stage a third pair of feet
are found, but they are short, and have only an indistinct articulation, or none at all. Eyes as well as
the first and second pair of «Kjzeber» (maxilles) can be distinguished, at least in some species. Some-

times the yolk substance of the body is present, in which case the young one passes this stage under

1) This statement does not apply to all Pa//ene-species. The species of this genus that I have examined, as will be
shown in the following, leave the egg, when the three foremost pairs of ambulatory legs have been developed and before the
arising of the fourth pair and the ovigerous legs.

PYGNOGONIDA. 13

the belly of the «mother» (the father it ought to be); sometimes the yolk is consumed, and then the
young one has to find its food. 4° In the third stage the larva gets the fourth and last pair of (ru-
dimentary) feet. The two preceding pairs (the three preceding must be meant) are very much devel-
oped. «The maxille» (i.e. palps and ovigerous legs) on the contrary, are still, in the species where
they are found, quite rudimentary. 5° After a new casting of the skin the animal nearly gets its
permanent shape, although the length of the body and the limbs is altered not a little.

Dohrn in a couple of works has given important contributions to the history of development,
first in his: «Untersuchungen iiber Bau und Entwickelung der Arthropoden» (1870) in the second sec-
tion of which, with the sub-title «Ueber Entwickelung der Pycnogoniden», he treats of the develop-
ment of the larva of Pycnogonum litterale, Achelia levis and Phoxichilidium sp. Still more important,
however, is the contribution, he has given in the monograph entitled: «Die Pantopoden des Golfes
von Neapel» (1881), in which, besides descriptions and figures of many different genera as Barana,
Ammothea, Clotenia, Phoxichilus, Phoxichilidium and Paliene, he gives an account of the larve known
to him, and their development 1.c. p.69—80. The principal progress in our knowledge of the devel-
opment given by Dohrn is that he justly shows how Kroyer has been wrong in his interpretation
of the development of the two foremost pairs of ambulatory legs, as if those pairs had arisen by an
uninterrupted development of the two hindmost pairs of limbs in the first form of the larva, «the em-
bryonal legs» as I have called them. Kroyer’s error is, I suppose, principally due to the fact that
in the very young larva of Pallene (or Pseudopallene) these limbs are almost or entirely wanting, and
so Kroyer has taken the two foremost pairs of legs (i.e. ambulatory legs) to be corresponding to the
two foremost pairs of legs (i.e. embryonal legs) in the larva of the other species. In the following I
shall again recur to this subject.

The works on the Pycnogonida by Hoek are well known. The two most important are:
«Report on the Pycnogonida» in the Voyage of H. M.S. Challenger (1881) in which he on the
plates XIX and XX represents the larve from their earliest development; and next his «Nouvelles
études sur les Pycnogonides» (1881) where on pl. XXX the different larve are represented. Besides
figures of well known forms, as Phoxichilidium, Ammothea and Pycnogonum, he especially draws
different species of the genus Mymphon. In the lastmentioned treatise, l.c. p.481 seq. Hoek gives
the results of his examinations in the following way: «Voici en peu de mots le résultat auquel je suis
arrivé: on trouve toujours, A quelques exceptions prés, comme premiére forme larvaire, un animal avec
trois paires d’extrémités, dont la premiére se termine en une pince et dont les deux suivantes sont
formées de deux articles et se terminent par des griffes allongées (larve Protonymphon). Les deux
derniéres paires d’extrémités sont — comme la premiére paire — des appendices simples, c’est-a-dire
quwelles ne sont pas divisées en deux branches comme celles des larves Nauplius. La bouche est
placée a la fin d'une excroissance de forme cylindrique ou conique, qui est implantée entre la pre-
miére et la seconde paire d’appendices: cette excroissance, cest la trompe, qui au moment de l’éclosion
de la larve est toujours trés courte, mais posséde déja cette forme conique ou cylindrique.

La maniére dont l’animal adulte se développe de cette forme larvaire est des plus simples.
Tandis que les trois appendices originaux se métamorphosent dans les trois paires d’appendices

céphaliques ou disparaissent (soit une, soit deux, soit — et ceci n’arrive jamais chez les individus

14 PYCNOGONIDA.

males — tous les trois paires), les segments thoraciques se développent successivement au bord posté-
rieur du corps, et aussit6t un nouveau segment formé, une paire de pattes se montre également
comme excroissances latérales de ce segment. Quand quatre paires de pattes se sont ainsi développées
aux quatre segments thoraciques (notons que l’ordre de développement des pattes correspond tout a
fait A leur rang dans le corps de l’animal adulte), l’excroissance terminale se change en un abdomen
plus ou moins rudimentaire.»

Morgan has given a little series of essays on the Pycnogonida, of which especially the last
one may be mentioned, entitled: «A Contribution to the Embryonalogy and Phylogeny of the Pycnogonids»
(1891). In this essay Morgan gives the development of Phoxichilidium maxillare |= femoratum
Rathke?], of Pallene empusa, and of Tanystylum orbiculare. He has more than his two above men-
tioned predecessors paid attention to the first development of the embryo, an examination that Kroyer
did not enter upon at all, and gives furthermore a very handsome series of the developmental stages
of the larva, especially the larva of Zanystylum; on the other hand I do not think his represen-
tation of the larval development of Pallene empusa to be correct. In his introduction L« p.2 Morgan
says: «For many reasons the present paper attempts in no way to give a complete answer from the
embryonal side. The very great difficulties of a suitable technique had slowly to be overcome, and
the time at command prevented a detailed description of the different organs arising from the germ-
layers, so that much remains that might be done,» but nevertheless his essay is a very important
advance in our knowledge of the development of these animals, as also his representation of the
structure and development of the eye in the Pycnogonida is rather exhaustive.

Passing now to my own description of the larval development I have to begin with the usual
complaint of not having had fresh material at my disposal; but on the other hand the Ingolf-Expe-
dition has brought home so rich a material well preserved in spirit that I suppose I shall be able to
give a more detailed and continuous description of the different stages of development in the larva.
I have been able to follow the development for a shorter or longer way in a considerable number of
Pycnogonida, belonging to the different families and genera as Nymphon grossipes, Sluiteri, elegans,
longitarse, robustum, spinosum, macronyx; Paranymphon spinosum*); Zetes (Eurycyde) hispidus; Pseudo-
pallene circularts and spinipes; Pallene hastata and brevirostris; Phoxichilidiwm femoratum; Pycnogonum
littorale, altogether 7 genera with 15 species. The species, the development of which I have most
complete, are Mymphon grossipes, N. robustum and Pseudopallene circularis, of which three species the
first and the last are those that have been particularly examined by Kroyer; but besides corrobo-
rating most of his statements and drawings (I have partly examined his original pieces) I have also
been able to increase and partly to correct some of them, which corrections especially apply to Psew-
dopallene circularts.

The segmentation, yolk-division, of the Pycnogonid ovum is complete, some-
times equal, sometimes unequal.

For the correctness of this thesis I must refer to Morgan, Contrib. Embryol., 1891, and I
have nothing to add. It is, I think, to be supposed, as Morgan does lec. p.23, that the difference
between equal and unequal segmentation, which latter is also continued in the difference between

1) In pl. II, fig. 22—24 are wrongly called spinipes in stead of spinosum.

PYCNOGONIDA. 15

large and small yolk parts, the macromeres and micromeres of Morgan, must be of a considerable
influence for the later development, and that it is connected with or proportioned to the mass of the
alimentary yolk in the egg; this fact again plays a very great part in the biology of the larva, as
this latter may exist without any other food, and keep enclosed in the safe egg-shell the longer, the
more alimentary yolk it brings along with it. Kroyer already has referred to this reciprocal relation
in his «Contributions to the knowledge of the Pycnogonida» (1845), comp. especially the third of the
five principal heads, under which he collects the results of his examinations, l.c. p.137, and to which
I have referred at p.12 seq. .

A germinal stripe asin the other Arthropoda, especially the Insecta, is not
formed. The ganglia as well as the separate pairs of limbs are formed or constricted
by degrees, from before backward, and, with the exception of the three foremost
ganglia and pairs of limbs, one after the other.

In the Arthropoda, especially the Insecta, the first germ of the embryo, as is well known, is
distinctly seen as a smaller or broader longitudinal band, the germinal stripe, along the under side
of the egg, and from this band the formation of the abdominal nerve cord and the pairs of limbs take
their rise almost at the same time; besides the formations are only small, and, as far as they really
are developed, they grow in size and length by a rapid multiplying, proliferation, of the cells. In
the Pycnogonida, on the contrary, a germinal stripe is never found, but the whole yolk mass is
immediately enclosed by a blastoderm, and all the limbs arise, if anything, from the sides of the bla-
stoderm by a segmentation of corresponding parts of the blastoderm with enclosed yolk mass. Further-
more only the three first pairs of limbs, the embryonal legs, are formed at the same time, while the
following four pairs, the ambulatory legs, are segmented off by degrees from before backward, most
frequently one pair after the other and with longer or shorter intervals of time. The ganglia seem
to develop contemporaneously with the embryonal limbs, and the ganglia of the abdominal side are
divided into two principal sections, a foremost one for the embryonal legs, and a hindmost one for
the ambulatory legs; but this latter mass of ganglia is not till a later stage separated into four or
five pairs of ganglia by degrees as the ambulatory legs develop. I may refer to my figures pl. I,
fig. 11 and pl. II, fig- 18, both representing what I call the second larval stage; the first figure repres-
ents Pseudopallene circularis, in which the whole mass of ganglia is seen still undivided, and only the
nerve mass belonging to the segments of the embryonal legs, has been slightly separated; the other
figure represents Mymphon Sluiteri, in which the two pairs of ganglionic centra may be distinctly
discerned united to a common mass, while the nerve mass of the first pair of ambulatory legs is well
separated from the following mass representing the ganglionic mass of the three following pairs of
ambulatory legs, in which mass, however, as yet only two pairs of ganglionic centra are to be seen.
The larva of Nymphon Sluitert upon the whole is more developed than that of Psewdopallene.

Between the embryonal and the larval stage there is no distinct boundary, in
so far as this boundary is to be determined by the embryo’s leaving the egg; but the
embryo leaves the egg sometimes on an earlier, sometimes on a later stage.

I have already before mentioned that according to the common view the limit of the embryo-

nal stage is formed by the embryo breaking the egg shell or egg membrane, and that the whole

16 PYCNOGONIDA.

development taking place before this act, is reckoned to the embryonal stage, but that I cannot agree
with this view. As the embryo, however, in the different Pycnogonida, breaks the egg shell some-
times after a shorter, sometimes after a longer development, nay, sometimes not even, until all the
limbs, the ambulatory legs included, have been developed, it will be understood that Korschelt and
Heider, Lehrb. Entwick. wirbell. Thier. 1890, in their large, well known text book can say of the
Pycnogonida that only «die meisten Pantopoden entwickeln sich mittelst Metamorphose», l.c. p. 662,
as if there were any important difference between the different Pycnogonida; Dohrn, Pantop. Golf.
Neap. 1881, even says lc. p.77: «Pallene hat die ganze Larvenentwickelung vollkommen unter-
driickt, das junge Thier, welches die Eischale verlasst, besitzt bereits alle definitive Extremititen,
wenn auch noch nicht in definitiver Gestalt» On the following page we find: «Wenn der Embryo
seine Reife erreicht hat, gleicht er in vielen Beziehungen der Larve von Phoxichilidium, welche den
Hydroidpolypen verlasst>. In my opinion the peculiarity in Pallene emaciata, the species mentioned
by Dohrn, is only to be found in the fact that the larva completes its development in the egg, in-
side the egg shell; and that this fact is not to be understood as something general in the genus, but
only as apeculiarity in this species among known forms I infer from the fact that in another Padllene-
species, Pallene hastata, 1 have found all larve free with only three pairs of developed ambulatory
legs, pl. I, fig. 18—r19. In the nearly related genus Pseudopallene I have even found the larva free in
its first stage with the two foremost pairs of ambulatory legs not yet quite developed, pl. I, fig.8. In
the following I shall enter into further details as to this fact. Also in other genera, for inst. in Mym-
phon, it may be found in the different species that the larve leave the egg shell sooner or later, with-
out any other difference in the course of development. It is quite another thing that a good bound-
ary really exists, but it can as usual be placed at the origin of the first larval form, here according-
ly it is to be applied to the form that has been called «Protonymphon» (Hoek) or «the Pantopod- ~
larva» (Dohrn).

Already in the introduction to this section on the larval development, I spoke of the usual
misconception with regard to the duration of the embryonal life, and gave a quotation frem the text-
book by Korschelt and Heider. I have here tried by demonstration on my figures to maintain
more in detail that all Pycnogonida pass through the same series of larval stages, whether the larva
«Protonymphon» frees itself at once, or remains in the egg till all the ambulatory legs are developed,
even if it has not attained its full length, segmentation, or all its appendages.

When the yolk-division is equal the whole blastoderm, only excepting the
middle and hinder parts of the dorsal side, participates in the formation of the em-
bryonal limbs and the proboscis. The embryo is free at once, is considered to bea
fully developed larva in the first stage, and is called Protonymphon (Hoek) or Pan-
topod-larva kat’ exochen (Dohrn, Morgan).

It is the enormous, overruling development of the embryonal limbs and the proboscis that is
a characteristic feature of this larval form, and this feature is found spread through the whole system
of the Pycnogonida, and has been known and described in different genera, as Phoxichilidium, Pycno-
gonum, Phoxichilus, Ammothea (Achelia), Ascorhynchus, and Tanystylum. It is also this larval form
which has originally played the greatest part as to the question of the systematic position of the

PYCNOGONIDA. 7

Pycnogonida in a so-called natural system (phylogenesis), several authors, and especially Dohrn,
having thought to find the Nauplius-type in it, a conception that Dohrn, however, as is well known,
has again abandoned, comp. his Pantopoden des Golfes von Neapel (1889), the section «Phylogenie
der Pantopoden», especially p. 87 seq.

When the yolk-division is unequal, only the foremost part of the blastoderm
participates in the formation of the embryonal limbs and the proboscis, while the
hindmost part of this latter with enclosed macromeres appears as a bag-like dilation
behind. The embryo remains wholly or partly in the egg, or, if it leave it, the em-
bryo remains at or on the father.

This larva which is to be regarded as the close of the first larval stage, has hitherto been
drawn from a less number of genera than the Protonymphon; besides from the large genus Mymphon
it is also known from the genera Pallene, Pseudopallene, and Zetles (Eurycyde), and I shall also be
able to add some new forms. It may, however, sometimes be questioned whether this larval stage
here is to be regarded as Protonymphon or not. Thus for instance in the hitherto known species of
the genus Nymphon a yolk-sack is always found at the close of the first larval stage, but this sack
sometimes is so very small, that one may be tempted to regard the larva in this stage as Protonym-
phon, as has been done by Hoek with regard to Mymphon gallicum.

In both forms this larval stage begins with a contemporaneous development
of the three pairs of embryonal limbs, ie. the chelifori and the embryonal legs, each
pair of the limbs representing its metamere with the ganglia, and besides an inter-
jacent process with an oral orifice at the point, ie. the proboscis.

A peculiar position is here occupied by the genera Pallene and Pseudopallene, which will be
bespoken more in detail at the close of this section.

The embryonal limbs accordingly appear at the same time as three pairs of large, flat protuber-
ances, warts, or processes on the under side of the blastoderm, anteriorly enclosing the single protuber-
ance of the proboscis, comp. my figure of the ovum of Pycnogonum littorale pl.I, fig.1. All seven
lumps are prolonged in a tubiform manner to lengthy processes, pl. I, fig. 2, the foremost free ends of
which in the embryonal limbs are segmented by two consecutive segmentations. Of these three pairs
of limbs the foremost pair, the chelifori, are almost from the beginning larger than the others, and
grow disproportionately, when compared with those, and the hindmost part, the part arising from the
trunk, is also more or less distinctly constricted from this as an independent joint, the scape. Further-
more the fact has also to be mentioned that the two terminal joints of the chelifori always in the
larva form a chela or a pair of pincers, so that these limbs get a very great resemblance to the chelze
of the Arachnida. It is a matter of course that this congruity with the said organ of the Arachnida
must be carefully taken into consideration when the question is of the systematic affinity of the two
groups; another question, however, is, how much importance we shall have to attach to it. Finally
is here to be mentioned the gland which is most frequently found in the basal part or the scape of
the chelifori, and the shorter or longer thorns, arising from this joint.

The two hindmost pairs of limbs, the embryonal legs, are uniform, always much smaller than
the chelifori. Their basal part is comparatively short, and never constricted from the body; the first

The Ingolf-Expedition. III. 1. 3

18 PYCNOGONIDA.

free joint is round and slender, and the second, or outermost, joint is always still thinner, most fre-
quently claw-shaped, and of about the same length as the preceding joint; sometimes, however, this
second joint is prolonged to a long, thin thread more than twice the length of the body, as for inst.
in Phoxichilidium femoratum, pl.1, fig. 4. The growth of the embryonal legs soon ceases, and even if
they, as is often the case, are kept in the following larval stages, they show no alteration.

The proboscis, like the embryonal legs, begins as a low protuberance, soon growing into
a conical process with more or less tapering sides, but without trace of any inner or outer division,
far less of a coalescing of constituent parts. The pharynx, however, is early developed, already in
this larval stage, and it is seen as a dark line stretching from the point of the proboscis towards its
base, as in Nymphon longitarse, pl. Il, fig.20, and in Nymphon macronyx, pl. Il, fig.9. The chitinous
ridges serving for the insertion of the Musculi retractores of the pharynx, are also early developed.

With regard to the interpretation of the proboscis I shall take the liberty to state my opinion
already in this place, although my interpretation is chiefly due to the structure of this organ found
in a much more advanced stage of development and especially in the imago. It is the unhappy note
by Latreille to his description of the Pycnogonida, Régne animal, éd. I. Tom IV (1829) which is
found again and again. The note, l.c. p. 276, note 3, runs thus: «Le siphon ... m’a offert des sutures
longitudinales, de maniére qu'il me parait composé du labre, de la languette et de deux machoires, le
tout soudé ensemble». It was to be thought that Dohrn®*) had succeeded in demolishing this notion,
and I can with all my heart agree with him, when in «Pantopoden des Golfes von Neapel» (1881) he
says: «Wir wiirden ... keinenfalls aber an eine Verschmelzung von extremitatenartigen Mundtheilen
zu denken haben», l.c. p. 109. We find nevertheless that Adlerz in his fine little essay, Contributions
to the Morphology of the Pantopoda («Bidrag till Pantopodernes Morfologi» (1888)) tries to maintain
the old view of Latreille. Adlerz founds his arguments especially on the fact that the two low-
ermost «antimeres» (Dohrn) of the proboscis receive nerves from special centra in the first abdominal
ganglion, comp. his fig.2 on pl. I, and the letters @ and wg in this figure. For these two foremost
centra with their fibrillous «punctuous mass» (Leydig: Punktmasse) in connection with the two
pairs of centra behind them in the same ganglion should show, how this ganglion is composed of
three original pairs of ganglia, but it is well known that to each pair of ganglia belongs a metamere
with a pair of limbs, which metamere could not then be anything but the two lowermost «<antimeres»
lc. p.10. To this is to be answered that, as no trace of limbs has ever been seen that might corre-
spond to or be merged in the two antimeres, as little has any trace been found of a pair of foremost,
free ganglia; besides it has to be remembered that the supply of nerves for the two lowermost meta-
meres most properly must be said to arise from the foremost one of the two, originally separated,
but now coalesced pairs of ganglia, in which, but not until a later stage, the corresponding foremost
pair of centra have developed. This view would also agree with my examinations, as I have also
found the ganglia to be originally uniform, and not until later showing distinct centra with their
fibrillous «punctuous mass» running into or stretching into the nerves of the limbs. I think upon
the whole that as to the morphology too great stress is at present laid upon the ganglia, and my

1) Already Zenker in «Untersuchungen iiber die Pycnogoniden» (1852) has p. 383 seq. rejected the supposition of
Latreille, referring to the representation given by Kroyer of the occurrence of the proboscis in the young larva.

PYCNOGONIDA. 19

examinations of the development of the Pycnogonida seem to me to show that in these animals the
separation of the nerve mass into ganglia only takes place by degrees, contemporaneously with a
corresponding separation of the somites of the trunk, and the separation and growth of the limbs,
comp. my figures of the first larval stages in Nymphon macronyx, pl. U, fig. 9, Psewdopallene circularis,
pl.I, fig. 11, and Nymphon Sluztert, pl. I, fig. 18, and with these figures may be compared the abdom-
inal nerve cord in Pseudopallene circularis in the second and ‘third larval stage, pl.I, fig. 12 and 15.
Upon the whole I doubt very much that a coalescing of well separated limbs really takes place, and
so much I know at all events from my own examinations that the union, supposed to take place of
the «arms» of the second pair of feet in the females of Lernzeopoda to a fastening knob, is only
apparent, each arm in reality ending in an independent knob; the two knobs are only more or less
loosely joined to a single knob — by a somewhat strong pressure they are easily separated. As a
paradigm on the coalescing of limbs this pair at all events cannot be used.

The proboscis is thus, after its origin and structure, especially the want of limbs, not
homologous with the other metameres of the body; but even if it be something particular, or, to use
the expression of Dohrn «<organum sui generis», it can in no way be said of it, as does this author,
that <im ganzen bisherigen Arthropodentypus nicht seines Gleichen, nicht einmal etwas ihm Aehn-
liches» is found, Pantop. Golf. Neap. 1881, p. 13, for I suppose that the proboscis of the Pycnogonida
will be found throughout the class of Arachnida, the only difference being that here it is free, large,
and predominant, while in the other Arachnida it most frequently is very small and hidden between
the gnathites. As an instance of a free proboscis in the Arachnida I shall refer to what in the follow-
ing is said of the genus Koenenia. As I have already indicated in the foregoing, in the chapter on
the terminology, p.3, there is still less reason to interpret it as, or give it the name of, head. A
similar structure of the mouth is otherwise found in some mites, as it also in several respects reminds
of the mouth in some higher, sucking worms (//rzdo). In the Insecta, especially in the Tipulida, we
find a parallel in the structure of the gullet; and as well in the Pycnogonida as in the Tipulida the

production of a pumping or sucking apparatus may be thought to be the conditional reason of the
common plan of structure. I think it may be taken to be a consequence of simple, mechanical laws
that, when a tube with firm walls is to form a pumping or sucking apparatus, the easiest thing will
be to place three plates with contiguous margins longitudinally in the the tube, and by ropes or
other suitable means make those plates to approach the wall of the tube at the same time, by which
motion the inner opening will be increased, and a pumping or sucking be brought about. With

regard to the Tipule I may refer to my paper, «The Gnathites of the Flies. Trophi Dipterorum»
(1881). On pl. Il, fig. 10 of this paper is found a transverse section of the gullet of a Tipulid of the

triangular form, so well known from a number of figures and transverse sections of the proboscis of
the Pycnogonida.

For the elucidation of the morphological significance of the proboscis I may also refer to the
figures in a recent work by two Danish zoologists, the doctors H. J. Hansen and Will. Sorensen:
«The Order Palpigradi Thor. (Koenenia mirabilis Grassi) and its Relationship to the other Arachnida»
(1898). This Arachnid has already earlier been the subject of a detailed examination and a systema-
tical view by Grassi: «<I Progenitori dei Miriapodi e degli Insetti' Memoria V. Intorno ad un nuovo

3°

20 PYCNOGONIDA.

Arachnide artrogastro (Koenenia mirabilis) rappresentante di un nuovo ordine (Microtelyphonida)»
(1886), which essay follows the preliminary paper without figures by the same author: «Intorno ad
un nuovo Aracnide artrogastro (Koenenia mirabilis) che crediamo rappresentante d’un nuovo ordine
(Microteliphonida)» (1885). As, however, the treatment by Hansen and Sorensen seems to me to
be far more solid than that of Grassi, and as the figures, in which I take most interest, are very
fine and distinct, I shall chiefly abide by this treatise written in English, with its plate, to the figure
2 of which I shall especially refer, as it shows the animal viewed from the lower side. The homology
of the proboscis of Aoenenia (0), which by the authors have been named with the unfortunate ex-
pression «mouth», while Grassi uses the much better one «papilla boccale», with the proboscis
of the Protonymphon is conspicuous, and the relation and situation as to the three foremost
pairs of limbs is exactly the same. Through the proboscis of Aoenenia a transition is next formed
to the mouth-structure in the other Arachnida, where I, contrary to Hansen and Sorensen, and to
the prevalent opinion, find the same proboscis, and it has only to be pointed out that the proboscis
in the other orders of Arachnida, on account of its position between the powerful gnathites, necessarily
must become shorter and more strongly chitinous than in Avoenenia; and nowhere, perhaps, is the
shortening and chitinization so accomplished as in.the Telyphona‘) so nearly related to HAoenenia.
But if the proboscis of Aoenenza and thus of the other Arachnida is homologous with that of the
Pycnogonida, and if it has never been supposed or is impossible to consider the proboscis of Koenenia
as formed by a coalescing of oral parts or gnathites, then it must be said that there is no reason at
all to suppose such a coalescing in the proboscis of the Pycnogonida.

In the figures 7 and 8 is next given a drawing of the proboscis of Koenenza, viewed from the
side and from below, but without any contribution as to its inner structure; it is only said that «the
muscles are very strong», and some fine, indistinct lines in fig.7 may be taken as an indication of .
these muscles. It cannot, however, be doubted that it is a sucking apparatus or a pump, as is also
shown even by a less strict examination.

The genera Pallene and Pseudopallene show in their larval form, as well in the first as in the
second stage, so great a difference when compared with the other larve of Pycnogonida, that there
might seem to be reason enough to set them up as a particular type; but as the difference chiefly
consists of a reduction of the embryonal legs or even a disappearing of these, it is morphologically
of small importance. I have not seen so young a stage as that I have drawn of Pycnogonum littorale
pl.I, fig.1 and 2; the youngest stage I have seen, is that of Pseawdop. spinipes, pl. 1, fig.7, where the
embryo is viewed from the side, lying in the egg, and with distinctly defined cheliforus, proboscis,
and foremost pair of ambulatory legs. In the cheliforus, the two outermost joints, the chela, are not
yet separated, and every trace of embryonal legs is wanting. That the swelling behind the cheliforus

must be the foremost pair of ambulatory legs, and cannot be one of the two pairs of embryonal legs,

1) Thus I cannot agree to the comparison between the proboscis («mouth») of Koezenta and the composite mouth,
with the general addition of the gnathites, of the other Arthropoda, and I think that the difference as to the mouth-struc-
ture may best be expressed in this manner that, while in the Arthropoda generally more pairs of limbs, the gnathites, close
together around the oral orifice, and are developed with reference to their partaking in the catching of and preliminary
dealing with the food, in Koezenia, as well as in the Pycnogonida, all the corresponding limbs are kept away from the oral
orifice, which accordingly in these forms is placed freely in the point of the «papilla boccale».

PYCNOGONIDA. 21

is shown by the series of larval forms, given in the following figures 8—11, and 16—17 of Pseudo-
pallene spinipes and circularis, as well as of Pallene brevirostris; as they, however, belong to the se-
cond larval stage, they will be mentioned more in detail in a following section. It may be possible,
of course, that I can have overlooked rudimentary larval legs; but in a somewhat later stage of the
same species I have seen no trace of these legs either, and as, in all places where I have observed
them, they have only appeared as one or two pairs of short, inarticulate processes, I am inclined to
suppose that here they have been quite absent. Of still less importance is the peculiarity that the
foremost pair of ambulatory legs have begun to appear so early, before the chelifori were quite
developed, and before the byssus-gland was formed. The two genera mentioned here must be supposed
to pass a great part of the second larval stage in the egg-shell.

Morgan, Contrib. Embryol. 1891 has not in Pallene empusa seen any trace of the foremost pair
of the embryonal legs, though he has seen some trace of the second pair; at all events I understand
the following quotation in that way, Lc. p.14. «On the sides of the body, just in front of the first
pair of ambulatory legs, are a pair of projections, one on each side. These are the beginning of the
third pair of limbs — the ovigerous legs. I have seen no traces of the second pair of appendages in
the ontogeny of Pallene».

In the basal part of the chelifori is most frequently found a large gland, the
byssus-gland, with an excretory duct opening through a shorter or longer hollow
thorn in the fore-margin of the said basal part.

_ The occurrence of a large gland in the chelifori has already been mentioned by Dohrn and
Hoek, who have also given descriptions and figures of it; by Morgan it is only drawn in the che-
lifori of Zanystylum orbiculatum; cp. the following.

This gland, the byssus gland, is most frequently distinctly conspicuous, and through the
epidermis it is seen to consist of a circle of large glandular cells gathered round a hollow, or reser-
voir, from which an excretory duct is seen to lead to the inner fore-end of the basal part of the
‘cheliforus, comp. the enlarged figure of the fore-end of the larva of NMymphon grossipes, pl.I, fig. 22.
In Nymphon elegans, pl. 11, fig.16, I have found the gland to be almost as distinct and of the same
structure; while it was far less distinct in Mymphon longitarse, pl.II, fig. 1g—20, Nymphon robustum,
pl. Il, fig.6, Nymphon macronyx, pl. Il, fig. 11, and in Mymphon spinosum, pl. I, fig. 13; but possibly it
was not quite developed, and so was not so well preserved in the spirit. The excretory duct opens
into the basal end of a shorter or longer hollow thorn, through the point of which the gland-secretion
is produced as a very thin thread of a considerable length. The thread, which stains strongly (I have
in all instances used picro-carmine), is easily seen, and is also to be seen in my figures of the larve.
The development of the gland begins very early in the embryonic stage on the border of the basal
end of the cheliforus and the corresponding metamere, but it is not finished until later in the first
larval stage, when the larva has left the egg wholly, or, at all events, with the fore part. The length
of the excretory thorn varies very much; generally it is short or even very short, but it can, as in
Pycnogonum littorale, gain a very considerable length, about the length of the embryonal legs, cp. pl. I,
fig. 3, where, however, the limit between the thorn and the free thread, which limit is difficult to see,

has not been indicated. The genera, in which I have found a distinct gland with a thread arising

22 PYCNOGONIDA.

from it, are Nymphon, Pycnogonum, Pseudopallene, and Pallene. In the last-mentioned genus, however,
I have in Pall. brevirostris found, in stead of a single thread originating from the common gland, a
bundle of seven, rather short, somewhat curled threads each issuing from an excretory duct of its
own, pl. I, fig. 16 and 17. I have seen no gland from which any of these threads might arise; but I
think it also probable, in comparison with what Hoek has found in Mymphon hamatum, what I shall
presently recur to, that each of the seven threads arises from a cell of its own. In Phoxtchilidium
Jemoratum 1 have found no trace of these glands, nor of their thorns and threads; the threads drawn
on pl. I, fig. 4, are the outermost joints of the embryonal legs, which are prolonged in a bristlelike
manner, and probably replace the wanting byssus-threads; this larva, with its parasitic way of living,
has no use for the hooks, to which in the other Pycnogonida the outermost joint of the embryonal
legs has been transformed. In VParanymphon spinosum'), pl. 11, fig.22—24, I have found indistinct
traces of the gland and excretory duct, and the thorns were long and closed. In Zetes hispidus, pl. I,
fig. 27, I have found a distinct gland, but no excretory duct from it, and also here the thorns were
closed. It may be possible that in the two last-mentioned cases a reduction of a commonly occurring
organ has taken place, as it would seem to be natural in Phoxichilidium; but it may also be supposed
that we have here a stage of transition from a simpler organ to the more perfect byssus-gland.
Dohrn and Hoek have already earlier described and drawn this gland, and Dohrn espe-
cially, in Bau u. Entwick. Arthrop. 1870, has from the larva in the first stage of Achelia levis (=
Ammothea levis) Taf. V, fig.7, given a figure of the gland with its excretory duct and a secretion-
thread (byssus) projecting from the long, pointed, hollow thorn, but from Pycnogonum littorale in a
similar stage only the hollow thorn, he, as it would appear, not having seen the thread, not to speak
of the gland. In the text he, when speaking of Achelia levis, describes the gland rather copiously,
but says nothing of its use or importance, le. p. 141 seq. Hoek, in «Report Pycnog. «Challenger»,» .
1881, draws this gland in NMymphon brevicollum and N. longicoxa, pl. XX, fig.2 and 5, and names it
in the explanation to the plates «Spinning apparatus in the mandible». In another NMymphon; N.
hamatum, pl. XX, fig.3 and 4 he draws, instead of the common gland, a whole heap of single miliary
gland cells each cell with its own secretion-thread. No doubt this last form of glands with its threads
corresponds to the bundles of threads I have mentioned in Padlene brevirostris; and as in the last-
mentioned species the gland was different in structure from that of the other species of the same or
of nearly related genera, so is also the structure of the gland in Nymphon hamatum peculiar, compared
with that in all the many species of Mymphon, from which the gland is known. Hoek in his text,
l.c. p. 141, compares the secretion-threads to the byssus-threads of the Lamellibranchiata, which com-
parison I have found so appropriate that I have given to the gland itself the name of «byssus-gland».
Dohrn generally draws the byssus-gland of the larve of which he gives figures, but he does not
always indicate it by special letters; when he does so, he gives the letters 7D, which in the explan-
ation to the plates are rendered as «Hautdriisen», and DHD, which are rendered as «Ausfiihrungs-
gang der Hautdriisen». In the text they are mentioned in the section entitled, «Geschlechtsorgane

und Entwickelung», especially on p.70 seq., and here Barana arenicola is also pronounced destitute

1) Cp. the note on p. 14.

PYCNOGONIDA. 23

of the excretory duct and thorn in contradistinction to Barana Castelli. Hoek, in Nouv. étud.
Pycnog., 1881, draws the gland with excretory duct and thorn in Ammothea longipes, pl. XXX,
fig. 40, and in Pycnogonum littorale, pl. XXX, fig. 45, as well as the gland alone in Mymphon gallicum,
pl. XXX, fig. 43.

The descriptions and figures of Dohrn, as well as most of those of Hoek do not very much
resemble those given by me; but I suppose that they generally represent a younger stage in the
development of the gland, whereas my figures, especially of the larva of Nymphon grossipes, pl.I,
fig. 22, and those by Hoek of Mymphon longicoxa, Report Pycnog. «Challenger», pl. XX, fig. 5, which
figures are very much alike, show the fully developed stage.

Morgan, in Contrib. Embryol., 1891, has drawn the byssus-gland in the larva of Zanystylum
orbiculatum, p\. 1V, fig. IX, in a shape most resembling my figure of the gland in Nymphon grossipes.
Else Morgan does not mention the gland at all.

I have been rather long in speaking of this gland, partly because it seems to me to have
hitherto been somewhat overlooked, and partly because I suppose it to have some morphological,
systematic importance, compared with the poison-gland in the corresponding pair of limbs in the
Arachnida. Possibly it might also be compared with the gland which Dohrn has described by the
name of «secretory organ», and which he mentions as occurring in the palps and the ovigerous legs,
or, where these limbs are wanting, in the corresponding metameres. I think at all events this com-
parison to be more obvious than the comparison with the sexual glands; comp. Dohrn, Pantop. Golf.
Neap. 1881, his «Excretionsorgane» and the following paragraph, «Geschlechtsorgane und Entwickel-
ung», p. 63 seq.

Dive development of the second larval stage begins with the growing of the
hindmost segment of the trunk, and the separation of a foremost ring with the first
pair of hind limbs, or ambulatory legs, upon which in a similar way the second and
third pairs of ambulatory legs are separated, while the fourth pair and the caudal
segment are seen behind as a three-cleft appendage. At the close of the development
of this stage the embryonal legs have fallen off, but the imaginal limbs and fore-
limbs, the palps and ovigerous legs, have not appeared, if they appear atall. Only
very rarely the chelifori fall off already on this stage. The byssus-gland is kept till
the development of the stage is finished.

The development of the second stage does not take place at once, but through more or fewer
castings of the skin, and in such a way, that sometimes a greater, sometimes a smaller interval is
found between the origin and the development of each of these three pairs of ambulatory legs, while,
however, the consecutive order is kept. Perhaps it may be called a little arbitrary to limit the second
stage in the way we have done here, as in some species so great a pause may occur during the
stage, especially after the development of the second pair of ambulatory legs, as is the case in Psew-
dopallene circularis, that we might as well place the limit of a larval stage after the development of
the second pair as after that of the third pair; in most Pycnogonid-larve, however, the development
is evenly advancing, till the third pair of ambulatory legs have been developed.

As in the preceding section the genera Pallene and Pseudopallene were especially mentioned

24 PYCNOGONIDA.

on account of their peculiarity, so we shall also here mention these genera as the last, and for the
same reason likewise delay the examination of the genus Phoxichilidium.

The genus Nymphon, which is, together with the subgenera Boreonymphon and Chetonymphon,
chiefly a palearctic form, presents by its numerous species and great extension the best opportunity
for European naturalists in these northern countries to make a continuous study of the development
of the Pycnogonid larve. It is also Mymphon grossipes of which we have the most detailed represen-
tation, already given by Kroyer, Kundsk. Pyenog. (1845), as it is also this species I shall use, and,
with reference to my figures, pl.I, fig.21—25, give a representation of its development during
this stage.

On the preceding figure, pl.I, fig. 20, representing the beginning of the second stage, is seen,
besides the three pairs of embryonal limbs, also the beginning of the two foremost pairs of ambulatory
legs, though only slightly pronounced; but in fig.21, which absolutely belongs to the second stage,
the first pair of ambulatory legs are already much developed, of about the same length as the trunk,
and with the last joint well developed to a bent, strong claw with two slender thorns, the auxiliary
claws, arising from the dorsal side near the base; the articulation of the leg, however, have not pro-
ceeded farther than to five joints exclusive of the claw. The second pair of ambulatory legs have not
been developed farther than to form a cylindrical process without any articulation or claw, neither
are in the body itself the corresponding segments conspicuous, which latter circumstance, perhaps,
may be due to a not quite good preservation. The byssus-gland, however, is now fully developed,
and the byssus-thread is distinctly seen to originate from the middle of the gland. In the following
figure, fig. 22, the fore-end of the larva has been represented much more enlarged to show distinctly
the structure of the byssus-gland. In the same figure the yolk-mass in the foremost part of the body
is also seen to consist of small particles (the micromeres?) smaller than those of the hindmost part (the .
macromeres?), of which, however, only a small portion has been represented; a particular interspace be-
tween the two yolk-masses is also distinctly seen. In fig. 23 the larva is represented much more devel-
oped, but still in the second stage; both the foremost pairs of ambulatory legs are now well devel-
oped, all nine joints, inclusive of the claw, being well separated, and the two auxiliary claws very
large; the third pair of legs are also rather long, four-jointed, but the last joint not yet claw-shaped,
and there is no indication of any auxiliary claws; the fourth pair of legs and the hindmost part of
the trunk form a solid body, while short curves behind indicate the wanting pairs of limbs; anteriorly
in the trunk the transverse-oval eye-knob with indistinct eyes is seen; the byssus-threads are still
present. Fig.24 shows the same larva from the lower side, and it shows how the yolk mass not only
fills the whole trunk, but also sends long processes into the three pairs of ambulatory legs. The yolk
is surrounded by a distinct sheath, seen with special distinctness in the third pair of legs, and forming
the walls of the intestine canal during the following development. Before, on both sides of the pro-
boscis, the embryonal legs are still seen, but they are now decaying, the matrix, or pulp — as it was
called in the old times — shrinking, and being consumed (?). In fig. 25 the embryonal legs have been
represented still more enlarged, by which means also the epidermis of the legs is distinctly seen in
contradistinction to the pulp, and where it is seen to have preserved its former size and firmness,

only the point of the outermost joint being a little retracted; an even shrinking or resorption of the

PYCNOGONIDA. 25

embryonal legs, or, at all events, of their exoskeleton is accordingly out of the question, we must sup-
pose them to be thrown off at once.

In his first essay, «Om Pycnogonidernes Forvandling» (On the metamorphosis of the Pycnogo-
nida) 1840, Kroyer already gives a rather detailed description of this stage, but of the embryonal legs
he has only seen one pair; his words are (l.c. p. 303): «Between the chelifori and the first pair of feet
I have sometimes seen projecting on the side a little process, fig.3c¢, appearing to consist of only
two joints and of a length of abt. 1/,,” (Danish); after its position I think it must be taken to be the
first trace of the palps.» The interpretation by Kroyer of this «little organ», to be sure, was not
correct; but to this question I shall recur in the following, in the section on the Pseudopallene-larva;
here I shall only add that the figure of the larva itself, fig.3@, is bad, and consequently the repro-
duction of this figure and other ones from his plate III, as they are given after the drawings
by Thornam, in the work of travel of Gaimard (1849) pl. 39, fig. 1 a—g, must be considered as a great
progress. In the work of travel the new principal figure, fig. 1d, resembles very well our fig. 23, and
the pointed thorns or hooks with which also the limbs behind the chelifori here are seen to end, agree
very well with the outermost joint or hook of the embryonal legs, but not with the imaginal fore
limbs in any stage whatever.

The second species the development of which I have been able to follow, is Mymphon robustum,
and I shall here describe the second stage, referring to my figures, pl. II, fig.2—6. A peculiarity of
this species, when compared with most of the other species, is the long time, during which the larva
remains confined in the egg-shell, or the egg-membrane and cast-off larval sloughs'). The first stage
of the larva in my possession is the second stage, shown in fig.2: here the larva is seen enclosed behind
by two membranes besides the egg-shell, and that it is not only the trunk which has cast off its
slough, may be seen from the proboscis, of which one cast-off slough is seen enclosed in the other, as
I have shown it more distinctly by a special figure, fig.3. In fig. 2 otherwise, all four pairs of ambu-
latory legs are seen in a course of development, the first pair as usual farther proceeded than the
others, but still only with slight constrictions indicating the beginning articulation. The segmentation
of the trunk is already here discernible, and it may also be observed that the first pair of embryonal
legs more than usually are distinguished by being earlier developed and thicker than the second pair;
as it is the case with the first pair of ambulatory legs, the old slough is also here seen loosely wrapping
the first pair of embryonal legs. In fig. 4 showing a stage a little more advanced, the proboscis as
well as the abdomen is seen lying in the two last sloughs; the second pair of ambulatory legs have
here grown comparatively more than any of the other limbs; besides the byssus-threads are now
secerned. In fig.5 and 6 the development has proceeded still farther, the two foremost pairs of am-
bulatory legs are completely articulated, while the third pair is still much shorter than the others,
and the articulation not quite finished. In fig.6 showing the larva from the lower side, the byssus-
gland is developed. The auxiliary claws are as a rule very small though quite distinct, which feature
is characteristic of the species.

Of Nymphon macronyx 1 possess, besides the larva on the first stage mentioned in. the fore-

1) It is also this species that for a longer time than any other Pycnogonid clings to the ovigerous legs of the father;
comp. the representation of this fact by Hoek, Pycnog. «Willem Barents», 1881, Taf. II, fig. 35.

The Ingolf-Expedition. III. 1. 4

26 PYCNOGONIDA.

going, also a couple of larve on the second stage, but not of the same degree of development. In
the younger of these larve, pl. II, fig. 11, the three foremost pairs of ambulatory legs are all developed,
and, contrary to what commonly is the case, all developed to the same degree. The byssus-gland is
also earlier developed than usual. In the somewhat older larva, fig.12, the first pair of ambulatory
legs are, as usual, much more developed than the second pair, and the third pair is not even
to be seen.

Of Mymphon Sthutert I have also drawn a phase of the second stage, pl. II, fig. 17, viewed from
the side, and fig. 18, viewed from below, but they show nothing remarkable with regard to the develop-
ment of the limbs.

Of Pycnogonum littorale 1 have an interesting drawing, pl.I, fig.4. The specimen was taken >
a score of years ago by the present doctores, Mr. Hector Jungersen and Mr. Johannes
Petersen, at Frederikshavn without particular statements as to the circumstances in which it was
found. It can be no other than a larva in the close of the second stage of a Pycnogonum s. str., but
from Frederikshavn and upon the whole from Denmark we know of no other Pycnogonum than P.
littorale, which moreover is commonly found on the locality in question. The embryonal limbs have
already quite disappeared, and no traces are to be seen, either from the upper side, represented here,
or from the lower side. That these limbs have disappeared is no wonder, as they usually do so, if
not so quickly, at all events in a short time; more remarkable is the absence of the chelifori. In
other instances the chelifori are embryonal. limbs which are kept throughout the life of the animal, if
not always with a fully developed chela, at all events, though, with fragments of it, and only in a
few forms, the genera Pycnogonum and Phoxichilus, the so-called order «Acerata» of Sars, and in
his family Colossendetde, the chelifori are quite wanting in the full-grown animal; there is, however,
a great possibility that the chelifori of the last-mentioned family are not thrown off until an advanced
stage, after the close of the larval development. Such, at all events, is the case in Colossenders
angusta (and gracilis) according to the observations of Hoek, which observations I shall here aug-
ment very much (in another Coloss. (macerrima) I have found the chelifori thrown off already in a
very young animal). The larva of Pycnogonum drawn here, is, judging by the development of the
ambulatory legs, in the close of the second stage, all three pairs of legs having reached the full seg-
mentation, also the claw. The body and the legs are smooth and naked, without the thick, rugged
exoskeleton distinguishing the grown Pycnogonum, and only the oculiferous tubercle and the three
knobs in the middle line of the back remind of the rugged appearance of the animal. The first seg-
ment of the trunk is uncommonly and unproportionally large.

The genera Pallene and Pseudopallene are distinguished from the other Pycnogonida, not only
by the above mentioned absence, or rudimentary state of the embryonal legs, but also by the two
foremost pairs of ambulatory legs arising contemporaneously, growing, and attaining to a considerable
development, before the growth of the third pair of legs begins. Of Pallene I have examined two
species, Pall. brevirostris and Pall. hastata. The former, Pall. brevirostris, is given on a rather early
stage, in which the two pairs of ambulatory legs are somewhat short and thick, with a single con-
striction in the middle besides the claw, pl.1, fig. 16; a special distinction is the separation, already

mentioned in the foregoing, of the byssus-gland in particular dermal glands, each with a byssus-thread

ld hn ll

PYCNOGONIDA. 27

ofits own, seven glands on each side of the animal, fig.17a.a. Of Pall. hastata I have two figures, pl. I,
fig. 18—19, which show a more advanced stage, the third pair of ambulatory legs being here already
very much lengthened, so that all three pairs seem to have been developed at the same time; from
the first figure, however, it is distinctly seen, that there must have been an interval between the
second and third pair. In the species of Psewdopallene the delay of the third pair of ambulatory legs,
is, however, much more considerable, as is already shown by the two figures of Pseudop. spinipes,
pl.I, fig.8—g. As to the further development I shall refer to the figures of Pseudop. circularis, pl.I,
fig. 10—14. In the two first of these figures the development has not gone farther than to the re-
presentation of Pseudop. spinipes, given in the preceding figure, but in fig. 12 it has gone much farther.
Here the two foremost pairs of ambulatory legs have been fully developed (of the four uniform legs
only the foremost right leg has been drawn), while the leg of the third pair is still only a bag-shaped
process with a characteristic stiff bristle implanted on the upper side, a little before the point. In the
same figure is furthermore seen the processes of the intestinal canal into the three pairs of legs,
going in the wholly drawn foremost leg quite into the outermost joint. No traces of embryonal legs
are seen, but neither, what is to be emphasized, is the least beginning of the imaginal fore limbs to
be found. In the fore edge of the first abdominal ganglion, or the suboesophageal ganglion are seen
through the epidermis a pair of short processes, as also a pair of still smaller, ballshaped appendages
farther back, inside the side margin; but no nervous fibres are seen to arise from these processes and
appendages. The anus is now distinctly open. Fig.13 represents the same larva from the upper side,
but with the two foremost pairs of ambulatory legs completely removed; the oculiferous tubercle with
the eyes is distinctly seen. Fig. 14 gives the last phase of the same stage. Here also the third pair
of ambulatory legs have been almost fully developed, only the last joint but one wanting; but still
the lower side of the first segment of the trunk is as naked as in the preceding phase, fig. 12.
Kroyer, in his second essay, Bidr. til Kundsk. om Pycnog. (1844), has given a description of
what he calls the first and second stages of Pallene intermedia (= Pseudopallene circularis); but the
description itself, and still more the figures in Gaimard’s work of travel (1849) pl. 39, fig. 2a.a—d., of
which figures Kroyer, no doubt, has been thinking, show distinctly that we here have two phases
of the same larval stage, ie. of the second stage, of which Kroyer treats, and the figures given by
Kroyer of the animals, fig. 2, a. and c. are completely answering to my figures 8 and 12—13, only
that in the first of my figures I have also the byssus-thread, and in the last one also the eyes. The
omission of the eyes may, I think, be due to the bad preservation of the larva whereby the elements
of sight have been removed from their position on the oculiferous tubercle; at least I believe to have
found these elements strewn round in the trunk of the original piece of Kroyer which I have had
occasion for examining, as well as the fresh specimen drawn here. Otherwise I think it to be the
real or apparent want of genuine embryonal legs, and the contemporaneous development of the two
foremost pairs of ambulatory legs, by which these latter get a certain resemblance to the former limbs,
which has induced Kroyer not only to suppose this degree of the second larval stage to be the
first, but also, what is much worse, led him to the wrong supposition of the real embryonal legs
developing into the two foremost pairs of ambulatory legs. But this same mistake, on the other

hand, has freed Kroyer from the present common wrong interpretation of the imaginal fore limbs
4*

28 PYCNOGONIDA.

as direct continuations of the embryonal legs. For my part I must regard it as a decided fact
that in all Pycnogonida the embryonal legs are quite thrown off during the second
larval stage, and that they are in no way identical with the later imaginal fore
limbs, the palps and the ovigerous legs, which latter also, and of this there is no
doubt, arise, although on the same metameres, still in other parts of these meta-
meres. The two genera mentioned here, Pallene and Pseudopallene, also show that even if greater
or smaller rudiments of the embryonal legs are found in the first larval stage, these rudiments have
quite disappeared in the second stage, so that here no trace of limbs is found, from which a new
development might arise.

The second larval stage of Phoxichilidium shows, in accordance with the parasitical habits of
the animal, a quite particular development. I have myself only had the first stage for examination;
but as this larva has repeatedly been the object of thorough examinations, I may nevertheless, relying
on these examinations, give a short survey of the development of its second stage, founded on the
representation by G. Adlerz, Bidrag till Pantop. Morphol. 1888, especially referring to his figures
4—12 in the two accompanying plates. The second larval stage then begins with the disappearing
of both pairs of embryonal legs, so that only slight traces or remnants are left. After a couple of
moultings, during which the rudimentary remnants of the legs by and by quite disappear, the imagin-
al limbs are begun, in the common way and in the common order, without, however, breaking
through the outer, common, wrapping membrane, until all the traces of the embryonal legs have dis-
appeared. Adlerz now supposes the foremost pair of imaginal fore limbs (II) i.e. the palps, to be
begun, cp. his fig. 10, upon which follows the further development of this pair of limbs in fig. 11 and
fig. 4 (pl.I); but in the first place the genus Phoxichilidiwum as imago has upon the whole no palps

(only the ovigerous legs are found in the male), and next both pairs of fore limbs arise from the .

lower side of the animal in the way common in Arthropoda, by the growth of a little cellular mass,
while Adlerz makes the extremity II develop as the other limbs of the Pycnogonida, especially the
ambulatory legs, by a swelling of the sides of the blastoderm or the ectoderm. According to this I
cannot take the small tubercles (II) on the side of the trunk to be the future ovigerous legs. Neither
can I have any great confidence in the representation or interpretation by Adlerz of the ganglionic
string in Phoxichilidium, cp. his fig. 4, pl.1; at all events, it does not agree well with his figure of
the same string in Mymphon Stroemit, which latter figure I take to be correct. In my opinion the
ganglion ug which he interprets as «undre svelggangliet» (the nether pharyngeal ganglion), and from
which a nerve is seen to branch off to the extremity II (it ought to be extr. III, as the former extre-
mity is wanting in all Phoxichilidia), must be the ganglion from the first segment of the trunk plus
the coalesced ganglia from the mietameres of the embryonal legs, or, as it might also be called, the
nethermost pharyngeal ganglion. Accordingly I think that after the description of this larva by Adlerz
is neither here to be found any continuity between the second pair of embryonal legs and the ovige-
rous legs of the male.

Semper, Pycnog. und Larvenf. 1874, who, like Adlerz, takes it to be the second extremity
(2), ie. the palps, which grows to a little protuberance (beyond which, for the rest, it never passes)

seeks to remove the difficulties by identifying the first pair of ambulatory legs with the completely

J.

PYCNOGONIDA. 29

disappeared second pair of embryonal legs, which is then marked as 3 I in his figures, pl. 16 and 17,
fig. 3—12. If Semper had known the development of more Pycnogonid-larve, his explanation would
immediately have appeared impossible to himself.

Morgan, Contrib. Embryol. 1891, has found in Pallene empusa, p. 24 seq. the same development
as I have found in my two species of that genus. I dare not, however, say of the development of
the three foremost pairs of ambulatory legs that it is «simultaneously», even if the interval between
the second and third pair is only small, as has been already observed. Nor can I, as is seen by the
foregoing, agree with Morgan as to the fact that «this third pair (i.e. the rudimentary embryonal
legs) grow out again to form the ovigerous legs». Finally I do not find that Padlene with Pseudo-
pallene deviates so much from the ordinary Pycnogonid-development, that there is sufficient reason to
finish, as does Morgan, the description of its ontogeny in the following way: «The development of
Pallene has become so much abbreviated that there is only a trace of the true Pantopod-larva found
in its ontogeny», cp. the foregoing.

Dohrn, Bau u. Entwickl. Arthrop., 1870, p.144—51, gives a detailed description of Achelia
(Ammothea) levis, and in pl. VI, fig. 11—13 he draws three consecutive «stages» of the development
of this animal, of which three stages I refer his first (in the explanation of the plates called «mittleres
Stadium») and second stages to my second stage. In the corresponding figures, fig. rr and 12, the
embryonal legs are still seen fully developed, with the exception that the last pair in fig. 12 are some-
what smaller than the other embryonal legs; but judging by my examinations, I regard the smaller
size, cp. also my fig.24 on pl.I, as a consequence of the fact that only the empty sheaths are left,
and that besides the points or outermost joints of these sheaths, as in my figure, are retracted, partly
into the preceding joint; I cannot suppose a reduction or real diminution of: this pair of legs to have
taken place. — Also the larve given by Dohrn, Pantop. Golf. Neap. 1881, pl. XI, fig. 21 and 24, and
determined as Phoxichilus vulgaris, must be referred to our second larval stage; but the specific
determination, especially with regard to the last figure, seems to me to be very doubtful. The first
figure, fig. 21, represents a normal Pycnogonid-development, in which I only think it to be not very
probable that a Phoxichilus should have kept its chelifori so long, and not rather have lost them,
either by reduction or throwing off, while the nearly related Pycnogonum has wholly lost them before
the close of the stage, cp. my figure, pl. I, fig.4. The improbability that Phoxichilus should have
kept the chelifori so long, is of course greater with regard to the older larva, fig.24, Pycnogonum
having lost them on a little earlier stage. But I am still more unable to believe that the imaginal
fore limbs, of which only the hindmost pair are developed and kept only in the male, should commence
and begin a development which was soon to be stopped or reduced; for I think it a fact that admits
of no doubt, that the appendages, marked in fig. 24 with II and III, are not rudimentary, reduced

remnants of the embryonal legs, but on the contrary a beginning development of the imaginal

_ fore limbs.

The third larval stage begins, when the fourth pair of ambulatory legs, which
have until now been far behind in development, together with the interjacent caudal
segment, begin to grow and develop, until they obtain their permanent shape, the

legs resembling the three foregoing pairs. The imaginal fore limbs, palps, and ovi-

30 PYCNOGONIDA.

gerous legs, now appear, after the embryonal legs and sometimes the chelifori have
been thrown off, the byssus-gland reduced, and the byssus-threads disappeared.
Moultings also take place during the development of this larval stage, until the
animal as «<a young one» obtains its complete shape, and now only grows in size and
outer investment of thorns and bristles; not till now appear the genital pores, or
openings, and the gland-pores.

The point of the development of this stage which is of most interest, is the rise and growth
or development of the imaginal fore limbs. Of the two pairs of limbs the foremost one, the palps,
seem to develop a little earlier and somewhat faster than the hindmost one, the ovigerous legs, but
I have too few examinations to venture to regard it as a rule or law. Where one or both pairs are
wanting in the grown animal, probably neither of them appear at all.

I have drawn the third larval stage of Nymphon grossipes, pl\.1, fig. 26—29, N. robustum, pl. 1,
fig. 7, NV. spinosum, pl. Il, fig. 14, and Pseudopallene circularis, pl.1, fig. 15. Besides the general remarks
stated above, I must especially point out that the palps immediately at their appearance are
found in quite another place than the first pair of embryonal legs just disappeared,
that is to say, quite anteriorly behind the base of the proboscis, at a considerable distance from the
ovigerous legs, while both pairs of embryonal legs from their rise to their being thrown off are almost
in contact at their base, arising together from the hindmost part of the lower surface of the first
chief division, cp. fig.27 @ and 4 with fig.24 6 and c. — Furthermore the palps in the first species
are sure enough proportionally considerably longer than the ovigerous legs, but in the palps the seg-
mentation is at most only indicated, a fact intimating that no moulting has taken place after the
beginning of the limbs, and that these latter have only arisen during this phase of the third stage.
In the fourth species, Pseudop. circularis, of course only the ovigerous legs have arisen, but their .
development has not gone farther than to their being segmented inside the smooth epidermis, and
thus they have not reached the second phase. The small particular drawings that in pl.I, fig. 28 and
29 have been given of the first beginning of the palps and ovigerous legs, show the common type
of the beginning of legs in Arthropoda, and I think it impossible to interpret them as the reduction
of the small, but powerful, well developed embryonal legs. In the drawing of Pseudo. circularis 1
have given the greater part of the ganglionic system with the four large ganglia of the body, the
very small abdominal ganglion, and the large, foremost ganglion, i.e. the coalesced ganglia correspond-
ing to the embryonal legs, or the nethermost pharyngeal ganglion, ganglion suboesophageum. By
comparison with the same nethermost pharyngeal ganglion in the second larval stage, fig. 12, it is
seen, how the same pairs of processes and appendages have changed, the processes having become
rather smaller, while the appendages have become large, lengthened, tapering to a pair of nerve
threads which I have been able to follow some way in the direction of the ovigerous legs. In Pad.
acus n.sp., finally, in which the fourth pair of ambulatory legs are very long, and which is of an
appearance almost like the drawing I have given of XW. grossipfes, pl.1, fig. 26, the beginnings have |
not gone farther than to form a pair of semiglobular tubercles before the base of the first pair of
ambulatory legs.

As already mentioned, Dohrn, Bau u. Entwickl. Arthrop. 1870, pl. VI, fig. 11—13, has given

re

ete a i a ie

PYCNOGONIDA. 31

three «stages» of the development of the larva of Ammothea (Achelia), the last one belonging to our
third larval stage. On the place of the imaginal fore limbs, not the embryonal legs, are here seen
two pairs of short, stubby appendages which I, in accordance with Dohrn, consider as the beginning
of the palps and ovigerous legs, that is to say, not as embryonal legs that, having been
reduced, now again are growing and developing, but as the imaginal fore limbs that
have arisen anew, and are originating in the way common in Arthropoda. To me, at
all events, the theory of the new formation of these limbs is no «make-shift>, as Dohrn thinks?) it
has been to Semper to enable him to homologize the Pycnogonida and the Arachnida, but I have
arrived at my opinion by following the development; it has, however, for me also the value to
diminish the difference between the number of legs in the thorax of the Arachnida and the r yeaa

onida, which difference, according to what has been stated here, would only be as 6 to 5,

Systematism.

Before entering upon the systematic representation of the species of the Pycnogonida, I shail
have to say some words concerning the place of these animals in the system of the Arthropoda upon
the whole, a question I frequently have touched on in the preceding section. To give here a copious
representation of all the different opinions that have been set forth with regard to this question, would
only be of little use, even if it might afford some interest to see how these animals have been regarded,
now as Crustacea, now as Arachnida, and at last have been referred neither to one nor the other of
these two classes, but have been declared a particular, independent group, outside of all the four
classes of the Arthropoda (Kingsley, Classif. Arthrop.), nay, have even by some authors been regarded
as a particular, fifth class (Sars, Pycnogonidea), comp. also Ihle, Phylog. Pantop.?). I think that by
the treating of the question of the position of the Pycnogonida in the system too small regard, or,
most frequently, no regard at all has been paid to the developmental history. As important momenta
of resemblance with regard to the Arachnida, I think we may point out: 1) The proboscis of the
Pycnogonida, which is found in all real Arachnida, and, as in these, is only a process of the trunk
ep. p.19. 2) The development of the body into two chief divisions, a thorax and an ab-
domen, each with its particular limbs or beginnings of limbs.— By considering the limbs
of the Pycnogonida the authors have always, or almost always, started from the point that the typical

1) Dohrn, Pantop. Golf. Neap. 1881, p.240, says of the theory of Semper: «Dadurch aber ward er (0: Semper)
genothigt, fiir die dann spater bei den Mannchen, nach geraumer Latenz wircklich hervorsprossende Extremitit III (i.e. the
second pair of imaginal fore limbs, or the ovigerous legs) den Eiertrager, auf den Nothbehelf der «Neubildung» zu verfallen,
— womit dann eben die ganze, auf diese Auffassung begriindete Homologisirung der Pycnogoniden mit den Arachniden
Banquerott machte».

2) The here mentioned paper by Ihle seems to me upon the whole to be most of all a curiosity, a pregnant instance
of what may be the result of the loosest systematizing without the slightest personal examination. As a specimen I shall
cite the following passage: «Als die Ahnen der Pantopoden betrachte ich die Myriopoden, erstens weil die letzteren die
einzigen Tracheaten sind, welche abdominale Extremitaten besitzen, und zweitens, weil — wenn wir die Arachnoideen und
Crustaceen ausschliessen —, die Myriopoden die einzig iibrig bleibenden Tiere sind, von welchen wir die Pantopoden ableiten

kénnen, sodass wir fast notgedrungen die ersteren als die Vorfahren der letzteren betrachten miissen .... und von ersteren
(9: Myriopoden) haben sich selbstindig Pantopoden, Insekten und Arachnoideen abgetrennt» (lc. p. 606).

32 PYCNOGONIDA.

number of homologous limbs in the Arachnida is six pairs, but in the Pycnogonida seven pairs. But, as I
have already tried to show in the foregoing, the seven pairs of limbs in the latter animals are not all reciproc-
ally homologous, and the typical number of pairs is not seven, but nine. Of these nine pairs of limbs
especially the four last pairs, the ambulatory legs, are not at all homologous with the ambulatory legs of
the Arachnida, but in all likelihood with the four pairs of small processes that have been pointed out in
the abdomen of the Arachnid-embryo, cp. Balfour, Notes on the Development of the Avaneina, 1880, and
Locy, Observations on the Development of A gelena nevia, 1886. Both the mentioned authors represent four
pairs of distinct beginnings of limbs arising from the abdomen of an embryo of an Agelena, Balfour,
lc. pl XIX, fig. 5—8 pp. or pp. 1—pp. 4, of Ag. labyrinthica, and Locy, 1.c. pl. I—IV, fig. 7—11, 13—14,
20—21 pr. app. of an Ag. nmevia. These beginnings which may reach a rather considerable length,
are by Balfour called «provisional appendages», a name also adopted by Locy. On the other hand,
I know of no instance of the genitals or their excretory ducts in any Arthropod being found in the
thorax or the limbs of this part, as would be the result of the common interpretation of the ambu-
latory legs of the Pycnogonida. 3) Furthermore we find in the Pycnogonida an organ so decidedly
of the Arachnid-type as the chelifori, with which also join 4) the embryonal byssus-glands, a
homologon of the poison-glands of the Arachnida. The’ want of particular respiratory organs gives
no information with regard to systematism, but it may be said to point to an origin or development
from primitive, larve-like forms. 5) Finally the presence of «auxiliary claws» (i.e. real claws) is an
important feature in the Arachnida in contradistinction to the Crustacea.

Relying on the points given in the foregoing, I think myself justified in classing the Pycnog-
onida among the Arachnida, as a group which with regard to the outer appearance is very much
deviating, as it has also become very strange by a strong development of organs that in other Arach-
nida are only begun, or have been reduced, and upon the whole adopted to the life in the water, .
especially the sea.

When we next pass to the inner systematism of the Pycnogonida, or the consecutive order
of the species, we shall first have to consider that the species, as far as they are known, form a close
and united series of forms, so that there can be no question of dividing them into different groups,
corresponding to the division into orders in the animal world in general, or in the Arthropoda in
particular. Even if we should follow the common notion, and consider these animals as having their
place outside the acknowledged four classes of Arthropoda, they would not for that reason become a
fifth class of the same rank as the other classes, nor will it be necessary to divide them into a smaller
or greater number of orders, suborders, families, subfamilies, genera, subgenera, species, and subspecies.
Corresponding frames may of course easily be put up, and have partly been put up; but then when
the animals are to be classed according to such frames, these frames soon appear to be quite artificial,
as many species may be placed as well at one place as at the other. Therefore we also see, how the
same species is, by different authors, referred, now to one genus or family, now to another, or even
to different so-called orders. The genera and families, of course, are still less decidedly fixed, but
change their position in a way and to an extent, unknown or inconceivable inside the class of Insects.
With a common larval type and common larval development, as it has been shown in the section on

the larval development, the orders and families that have been put up, have in reality only been

PYCNOGONIDA. 33

based on the fact, whether the foremost limbs, as well the embryonal limbs as the imaginal limbs,
continue the typical development, or their development is checked on an earlier or later stage, whether
they go through a slighter or more marked retrograde development, or how long they are kept upon
the whole. How small a systematic importance these foremost limbs have, may be seen, among other
things, by the fact that a pair of these limbs may be kept in one sex, while it is thrown off in the
other, and thus the reason of the keeping seems only to be purely biological; moreover the keeping
or the throwing off takes place without producing or corresponding to any other difference in struc-
ture between the two sexes. T’o make such organs the base of the division into orders, seems to me
very unfortunate, and it is only for want of better characteristics that I have used these limbs as
family distinctions — in reality they are only of value as generic distinctions. Therefore I do not
think it necessary to enter upon a detailed valuation of the orders that have been put up.

Among the different systems those of Wilson, Syn. Pyecnog. New. Engl. 1878, and Hoek,
Report Pycnog., 1881, and Nouv. étud. Pycnog. 1881, seem to me to be the best. The system of
Wilson must be said to be well worked out, but on the other hand it is rather artificial, too much
stress being laid upon characteristics taken from the auxiliary claws and the number of joints in the
palps and the ovigerous legs. The system of Hoek in Report Pycnog. is merely a grouping of the
genera without any real arranging of these genera inside the families. In his system in Nouv. étud.
Pycnog. p. 106 the number of families has been reduced to four, and these four correspond to my
system, as well with regard to the appellations as, chiefly, to the characterization, and the genera
contained in each of them; it is however to be noted that the genus /adlenopfsis has by Hoek been
referred to Phoxichilide, but by me to Nymphonide. ‘The genealogical table given by Hoek with
its extremely problematic primitive form Archipycnogonum, 1 am not able to appreciate rightly.

The system I have used, is more particularly intended for the Pycnogonida brought home by

the Ingolf expedition with the object of its also being able to comprise the new species.

I. Fam. Nymphonide.

Corpus manifeste in segmenta partitum.

Rostrum cylindricum, inflexibile, libratum vel nutans.
Chelifori expleti, chela instructi.

Palpi vel expleti, vel imminuti, vel deficientes.

Pedes oviferi in utroque sexu.

The trunk distinctly segmented.

The proboscis cylindrical, inflexible, horizontal, or directed obliquely downward.
The chelifori well developed (with chela).

The palps well developed, or rudimentary, or wanting.

Ovigerous legs present in both sexes.

As it will appear from the family-diagnosis, this family: comprises the species belonging as
well to Nymphon as to Pallene, that is to say, the families Mymphonide and Pallenide of Sars. An

The Ingolf-Expedition. III. 1. 5

34 PYCNOGONIDA.

essential reason for me to incorporate the two families has been the fact that Padllenopsis which is
most closely related to the genus Padlene, shows, by the formation of its palps that it will not do to

lay too much stress upon the presence or absence of these organs.

I. Subfam. Nymphonini.

Palpi expleti, pluries partiti.

Palps well developed, with more joints.

1. Gen. Nymphon (Fabr. 1794).
Nymphon, Wilson, Syn. Pycnog. New-Engl., 1878.
Chzetonymphon, Sars, Pygnog. bor. arct., 1888, pro parte.
Boreonymphon, Sars, ibid.
The genus Mymphon with the limits which have been given to it here by Wilson, includes
a great number of species that might naturally be distributed to several groups, but the differences
seem to me to be too small to justify the division into more genera, or the separating of more or
fewer species of the genus Mymphon of Wilson. The genera Chetonymphon and Boreonymphon,
for inst, which have been separated by Sars, l.c. p.352 and 354, seem to me too little characteristic
to be taken as more than groups of species, and with regard to WV. macronyx which has been referred
to Chetonymphon, 1 think it even doubtful, if it might not more easily be placed among the species
that Sars still keeps as the genus Wymphon.
The species of the genus, brought home by the Ingolf, may be arranged as shown in the
following analytical table.

a. The trunk naked.
(The fingers of the chelz (i.e. both the immovable and the movable finger) dentate.
The auxiliary claws well developed).

b. The oculiferous tubercle pointed.
1. N. grossipes Fabr.

2. N. Sluiteri Hoek.
b. b. The oculiferous tubercle truncate.

ce. The first tarsal joint shorter than the second.
N. brevitarse Kr.
cc. The first tarsal joint as long, or longer than the second.

d. The two last joints of the palps short and thick. .
(The claws short, powerful.

The fingers of the chele short).
N. serratum G. O. Sars.

N. megalops G. O. Sars.

ns

6. N. Sarsii n. sp.
d. d. The two last joints of the palps long, thin.

e. The claws short, powerful.
7. N. Hoekii n. sp.

8 N. Stroemii Kr.

\

PYCNOGONIDA. 35

e.e. The claws long, thin.
f. The fingers of the chelz short.

g. N. longitarse Kr.

ff The fingers of the chelz long.
to. N. Groenlandicum n. sp.
11. N. elegans Hans.
12. N. leptocheles G. O. Sars.
13. N. macrum Wils.

a.a. The trunk hairy.
g. The fingers of the chelz dentate.
(The auxiliary claws well developed).

h. The hair-covering spread, fine.

14. N. macronyx G. O. Sars.
h. h. The hair-covering dense, coarse.

15. N. spinosum Goods.

16. N. tenellum G. O. Sars.
g. g. The fingers of the chelz simple, strongly arcuate.

(The auxiliary claws rudimentary).
17. N. robustum Bell.

1. Nymphon grossipes Fabr.

Pycnogonum grossipes O. Fabricius, Faun. Groenl. 1870, p. 229.

eer grossipes Kroyer, Kundsk. Pycnog., 1844, p. 108.
— — Idem, Gaimard, Voy. Scand. Lappon., 1849, pl. 36. Fig. 1, a-h.
— — Wilson, Syn. Pycnog. New-Engl., 1878, p. 20. Pl. VII. Fig. 1, a-q.
— — Hansen, Kara-Hay. Pycnog., 1886, p. 16. Tav. XVIII. Fig. 8, 8a.
— - Sars, Pycnogonidea, 1891, p.65. Pl. VI. Fig. 2, 2 a-.

Nymphon mixtum Kroyer, Kundsk. Pycnog., 1844, p. IIo.
— — Idem, Gaimard, Voy. Scand. Lapp., 1849, Pl. 35. Fig. 2, a-f
— — Hansen, Fortegn. dansk. Pycnog., 1884, p. 649.
— — Idem, Zool. Dan., 1885, p. 128. Tab. VIL. Fig. 19.
— — Sars, Pycnogonidea, 1891, p. 68. Pl. VI. Fig. 3, 3 a-i.

I cannot side with Sars in considering the NM. mixtuwm of Kroyer as a good species, but
must agree with Wilson in uniting NM. grossifes and N. mixtum; perhaps I may also be allowed to
point out that Hansen in his list of Danish Pycnogonida seems inclined to approve of such a union.

Occurrence. The Ingolf-stations 2, 31, 87, 95, 127 state it to be taken in the Davis Strait,
the Denmark Strait, as well midway between Greenland and Iceland as nearer to the latter island,
in the mouth of «<Bredebugt»; further also in the Greenland Sea, and finally as far south as the
boundary of the Norwegian Sea midway between the Farée Islands and Iceland. The depths were from
50—752 fathoms (Danish).

Further it is found at the Zoological Museum from many localities. When it has been called

by other names than that of NV. grossifes, the name in question has been added in a parenthesis.
s*

36 PYCNOGONIDA.

From the western coast of Greenland it is found from the following localities: Near Upernivik, 18
fath., stones with a few alge («Fylla», Holm); the port of Sukkertoppen, to fath., stones with
algze (idem); between the mouth of Kvanefjord and Frederikshaab, 16 fath., (idem); between the rocks
and islands outside of Frederikshaab, 1o—25 fath. (idem); the straits at Igaussak (south of Frederiks-
haab), to fath. (idem); from the Davis Strait: 67° 4’ Lat. N. 54° 28’ Long. W., 32 fath., stones without
algze (idem); 66° 32’ Lat. N. 35° 34’ Long. W., 100 fath. (idem); (mza¢eem) 66° 16’ Lat. N. 26° 8’ Long. W.
330 fath., bottom temperature — 1° (Wandel); 65°35’ Lat. N. 54° 50’ Long. W., 80 fath. («Fylla», Holm);
from the eastern coast of Greenland, in the Greenland Sea: 72° 26' Lat. N. 19° 35’ Long. W. 105 fath.
(Deichmann); 72° 53’ Lat. N. 20° 36’ Long. W., 96 fath. (idem); at Iceland, off Stykkesholm (H. Jonsson);
in the Norwegian Sea, 63° 15’ Lat. N. 9° 35’ Long. W. 270 fath. (Wandel); (s#zxtwm, the original specimen
of Kroyer) Trondhjem-Fjord, south of Laxen, 15 fath.; in the channel between the Farde Islands and
the Shetland Islands 61° 23’ Lat. N. 5°04’ Long. W. 225 fath. (Wandel).

Distribution. Here it is first to be pointed out that I have united M. grossipes and mixtum,
so that the general reference to Sars, Pycnogonidea, 1891, here applies to both the species of Sars.
After our conception of the species, WV. grossifes should be known as one of the most widely spread
Nymphon-species, from the Kara Sea, the Barents Sea, the seas round Greenland, and the eastern coast
of North America towards the north, to the North Sea, nay, even into the Sound, towards the south.

Accordingly the Ingolf-expedition has not increased the distributional area of the species.

2. Nymphon Sluiteri Hoek.

Nymphon Sluiteri Hoek, Pycnog. «Willem Barents», 1881, p. 18. Pl. II. Fig. 30-34.
— Hansen, Kara-Hav. Pycnog., 1886, p.12. Tab. XVIII. Fig. 5, 5 a-b.
— Sars, Pycnogonidea, 1891, p. 73. Pl. VII. Fig. 2, 2 a-g.

Hoek says of this species that its oculiferous tubercle is «non valde exaltata apice truncata»,
le. p.18, which on the following page is rendered by: it «is not very elevated and rounded at the
apex»; but as well Hansen who has examined some 40 specimens, as Sars who has examined <a
great many», and the present author have only seen specimens with very pointed oculiferous tubercles,
so that, no doubt, the single specimen of Hoek has, as is also observed by Hansen, been defective
with regard to the oculiferous tubercle; Hoek also says of it that «the state of preservation of this
specimen was not quite satisfactory», l.c. p. 19.

Occurrence. The Ingolf-stations are the following: 105, 116, 138, according to which it has
been taken in the Norwegian Sea, from the Farée Islands in the south in an almost straight line to
Jan Mayen in the north; the depths were 371—762 fath.

Distribution. The species had hitherto only been found as far north as the Kara Sea, the
Barents Sea, and midway between the Finmark and Beeren Eiland, at a depth of 20—60 fath., in a
single instance of 160 fath, Sars, Le p.75. By the Ingolf it has been taken considerably farther to
the south, until 63° 22’ Lat. N., and at somewhat greater depths, until 762 fath.

OF A
= A LiFoRWA

PYCNOGONIDA. 37

3. Nymphon brevitarse Kr.
Nymphon brevitarse Kroyer, Kundsk. Pycnog., 1844, p. 115.
ae — Idem, Gaimard, Voy. Scand. Lappon., 1849, Pl. 36. Fig. 4, a-f.
= — Sars, Pycnogonidea, 1891, p. 61. Pl. V. Fig. 3, 3 a-g.
Nymphon grossipes (Fabr.) Wilson, Syn. Pycnog. New-Engl., 1878, p. 491. p. p.

I cannot follow Wilson, when he not only incorporates the NV. mixtum of Kroyer, but also
the WV. brevitarse of the same author into the species NV. grossipes of O. Fabricius.

Occurrence. The Ingolf-stations are 95 and 96, in the middle of the Denmark Strait. The
depths were 752 and 735 fath. and the bottom temperatures 2°,1 and 1°,2.

Distribution. The species was formerly only known from Greenland (Kroyer), and one

specimen from the straits of Matotschkin Sharr, on a depth of only ro—15 fath.

4. Nymphon serratum G.O. Sars.

Nymphon serratum Sars, Crustac. Pyenog., 1880, p. 471.
— — Hoek, Pycnog. «Willem Barents», 1881, p. 16. Pl. I. Fig. 24—28, Pl. Il. Fig. 29.
— — Hansen, Kara-Hav. Pycnog., 1886, p.7. Tab. XVIII. Fig. 2, 2 a-c.
— — Sars, Pycnogonidea, 1891, p.g5. PL X. Fig. 2, 2 a-h.

Occurrence. The Ingolf-stations are 93, 94, and 127, the two first in the Denmark Strait,
towards the coast of Greenland, the last one in the Greenland Sea, not far from the northern coast
of Iceland. The depth was in the Denmark Strait 204 and 767 fath., in the Greenland Sea
only 44 fath.

Further it is found at the Zoological Museum from the Davis Strait: 65°35’ Lat. N. 54°50’
Long. W., 80 fath. («Fylla»>, Holm), and 66° 32’ Lat. N. 55° 34’ Long. W., 100 fath. (idem).

Distribution. Sars, Pycnogonidea, 1891, p.97, regards it as a genuine arctic species, from
the sea between Beeren Eiland and Spitzbergen (Sars), the Barents Sea (Hoek), the Kara Sea and the
Davis Strait (Hansen), to which the Ingolf thus adds the southmost parts of the Greenland Sea and

~ the Denmark Strait.

5. Nymphon megalops G. O. Sars.

Nymphon megalops Sars, Prodr. Crustac. Pycnog., 1877, p. 366. n° 7.
—_— - — Idem, Pycnogonidea, 1891, p.98. Pl. X. Fig. 3, 3 a-g.

Occurrence. The Ingolf-stations 93, 138, and 143 show it to be taken as well in the Den-
mark Strait as in the southern part of the Norwegian Sea, at the first station at a depth of 767 fath.,
while at the two last-named stations in the Norwegian Sea the depths were respectively 471 fath.
and 388 fath.

Previous to the Ingolf expedition it was found at the Zoological Museum from a high degree of
latitude in the Denmark Strait: 65° 39’ Lat. N. 28° 26’ Long. W,, 553 fath., the bottom stones and shells

38 PYCNOGONIDA.

(«Fylla»>, Ryder); near Iceland, one Danish mile east of Seydisfjord, 135 fath., the bottom black ooze
(Wandel), and in the Farée-Shetland Channel, 61° 23’ Lat. N. 5° 04’ Long. W., 255 fath., bottom tempe-
rature 0° (idem).

Distribution. Sars, Pycnogonidea, 1891, p. 100, regards this species as a genuine arctic
form, found to the south till off Storeggen, 63° 10’ Lat.N. The Ingolf carries it southward until 62° 58’,
and the collections of the Museum till 61° 23' Lat. N. that is to say, southeast of the Faréde Islands.

6. Nymphon Sarsii n. sp.
Tab. III. Fig. 1—6.

Junior (poris genitalibus nullis).

Corpus subrobustum.

Collum breve.

Tuber oculare sat altum, robustum, inerme; ocelli magni, rotundati, in lateribus contingentes, anteriores
posterioribus paulo majores.

Segmentum caudale breviusculum, paulum curvatum atque nutans.

Chelifori sat graciles, scapo longiusculo, quam chela multo longiore; chela breviuscula, palma longius-
cula quam pollice paulo longiore.

Palpi breves, articulis binis ultimis crassis, longitudine subzequalibus, conjunctis longitudinem articuli
tertii fere explentibus.

Pedes oviferi sat longi, ungue paucidentato.

Pedes gressorii breves, crassi, articulis tarsalibus subzequalibus, conjunctis tertiam partem longitudinis
articuli alterius tibialis explentibus, articulo altero tarsali serie aculeorum longorum in duabus .
partibus marginis interioris instructo. Unguis brevis, crassiusculus, unguiculis auxiliaribus sat
gracilibus, dimidiam longitudinem unguis fere explentibus.

Long. tota 9,6™™. Rostri 2,8™™. Corporis 5,3™. Segmenti caudalis 1,5™™.

The trunk rather robust.

The neck short.

The oculiferous tubercle rather high, robust, rounded, without teeth; the ocelli large, round, touching
each other at the sides, the foremost a little larger than the hindmost.

The caudal segment rather short, a little bent, and directed downward. |

The chelifori rather slender, the scape somewhat long, much longer than the chela; the chela rather
short, the palm somewhat lengthened, a little longer than the movable finger.

The palps short, the two last joints thick, of about equal length, both joints together about as long
as the third joint.

The ovigerous legs rather long, the claw with only few teeth.

The ambulatory legs short, thick, the tarsal joints about equally long, taken together as long as one
third of the second tibial joint; the second tarsal joint with a series of long thorns along the

*~

PYCNOGONIDA. 39

two thirds of the inner edge. The claw short, rather thick, with rather slender auxiliary claws
of about half the length of the claw itself.
Total length 9,6™™. The proboscis 2,8™™. The trunk 5,3™™. The caudal segment 1,5™™.

This species resembles very much the following species, V. Hoekiz, but is easily distinguished
from it by the shape of the chelifori and palps, and the much longer caudal segment. Only one single
specimen is known, which moreover is not quite full-grown.

Occurrence. The Ingolf-station 2; the locality the boundary between the Norwegian Sea
and the Atlantic, midway between the Farde Islands and Iceland, 63° 4’ Lat. N. 9° 22' Long. W.; the
depth was 262 fath., the bottom clay and gravel, and the bottom temperature 5°3.

7. Nymphon Hoekii n. sp.
Tab. Ill. Fig. 7—13.

Junior (poris genitalibus nullis).
Corpus sat robustum.

Collum breve.

Tuber oculare sat altum, robustum, obtusum, inerme; ocelli sat magni, rotundati, in lateribus contin-
gentes, anteriores posterioribus vix majores.

Segmentum caudale breve, crassiusculum, paulum sursum curvatum.

Chelifori crassiusculi, scapo brevi, quam chela breviore; chela longiuscula, palma breviuscula, quam
pollice breviore.

Palpi breviusculi, articulis binis ultimis sat gracilibus, longitudine subzequalibus, conjunctis articulo
tertio manifeste longioribus.

Pedes oviferi sat longi, ungue multidentato.

Pedes gressorii breves, crassiusculi, articulis tarsalibus longitudine subzequalibus, conjunctis dimidiam
longitudinem articuli alterius tibialis non explentibus, articulo altero tarsali absque aculeis in
margine interiore. Unguis brevis, crassiusculus, unguiculis auxiliaribus sat gracilibus, dimidiam
longitudinem unguis vix explentibus.

Long. tota 8™™. Rostri 2,8™™. Corporis 5,37". Segmenti caudalis r™™.

The trunk rather robust.

The neck short.

The oculiferous tubercle rather high, robust, rounded, without teeth; the ocelli rather large, round,
touching each other at the sides, the foremost hardly larger than the hindmost.

The caudal segment short, somewhat thick, bent a little upward.

The chelifori rather thick, the scape short, shorter than the chela; the chela rather long, Bie palm
somewhat short, shorter than the movable finger.

The palps somewhat short, the two last joints rather slender, of about equal length, both together
distinctly longer than the third joint.

40 PYCNOGONIDA.

The ovigerous legs rather long; the claw with many teeth.

The ambulatory legs short, rather thick; the tarsal joints of about equal length, together not so long
as half the second tibial joint; the second tarsal joint without thorns in the inner edge. The
claw short, somewhat thick, with rather slender auxiliary claws, scarcely half as long as the
claw itself.

Total length 8™™, The proboscis 2,8™". The trunk 5,3™".-The caudal segment. 1™™.

This species is very much like the preceding one, but belongs, by the structure of its palps,
to another specific group. Only a couple of not full-grown specimens have been taken.

Occurrence. The Ingolf-station 95, in the middle of the Denmark Strait, 65° 14 Lat. N.
30° 39' Long W.; depth 752 fath., bottom temperature 2°,1.

8. Nymphon Stroemii Kr.

Nymphon Stroemii Kroyer, Kundsk. Pycnog., 1844, p. III.
— — Idem, Gaimard, Voy. Scand. Lappon., 1849, Pl. 35. Fig. 3, a-f.
— — Wilson. Syn. Pycnog. New-Engl., 1878, p.17. Pl. VI. Fig. 1, a-h.
— — Hansen, Kara-Hav. Pycnog., 1886, p.9. Tab. XVIII. Fig. 3.
— — Sars, Pycnogonidea, 1891, p. 80. Pl. VIII. Fig. 2, 2 a-k. p. p.
Nymphon gracilipes Heller, Crust. Pyenog. Tunic. 1875, p. 40. Taf. IV. Fig. 15. Taf. V. Fig. 1-2.
_ — Sars, Pycnogonidea, 1891, p. 83. Pl. VIII Fig. 3, 3 a-g. p.p.

As Wilson and Hansen I also must acknowledge that I cannot keep distinct WV. Stroemiit
and WV. gracilipes; for even if it may frequently be easy enough decidedly to refer a specimen to one
or the other of the two forms, the decision is still oftener very difficult or quite impossible, or we
find an intermingling of the separating characteristics.

Occurrence. The Ingolf-stations are: 2, 3, 4, 29, 32, 35, 44, 87, and 106. The number of
stations shows to be sure that this species has been taken very frequently, but outside of the south-
most part of the Norwegian Sea, and a little way into the Atlantic, as also in the western part of
the Davis Strait, it has only been taken once by the Ingolf in the Denmark Strait, at the mouth of
Bredebugt on Iceland. The depths were from 68—545 fath.

From the collections of the Zoological Museum I may add the following localities: the Davis
Strait, 63° 56’ Lat. N. 52° 12’ Long. W., 130 fath. (Wandel); 65° 27' Lat. N. 54° 45’ Long. W. (idem); 65° 35’
Lat. N. 54° 50’ Long. W., 80 fath. («Fylla»1884); the Denmark Strait, 65° 39’ Lat. N. 28° 25’ Long. W., 553
fath. («Fylla» 1888); the Greenland Sea, 69° 25’ Lat. N. 20° 1’ Long. W. 167 fath. (Bay); the west coast of
Norway (the original specimen of Kroyer); the Skager Rack, close to the Norwegian coast, 275 fath.
(Joh. Petersen); the Skager Rack, the Skaw in $.S.E. 34 miles, 210 fath. (idem); the Cattegat (idem).

Distribution. Sars gives a different sphere of distribution for his two species, V. Stroemat
and WV. gracilifes, a more southern one for the former, lesser form, and a more northern one for the
latter, somewhat larger species. The limit as to the independence of the species that might be found

in this circumstance, loses to me much of its importance, when I find forms quite corresponding to

PYCNOGONIDA. 41

the WV. Stroemii of Sars so far north as 65° 34’, in the Davis Strait; on the other hand, however, I
must acknowledge that most of the specimens that I after Sars temporarily determined as NV. Stroemii,
are from more southern stations (2, 3, 4, 35, 44, 67), while those that I determined as XN. gracilipes,
are from more northern ones (29, 32, 106). It is, however, a well known fact that many animals, for
inst. among the Crustacea, in the higher latitudes by and by assume a somewhat different shape and
especially a more considerable size; I shall only remind of so well known animals as Gammarus
locusta and Amathilla Sabinet.

If NV. grossipes be taken in a so wide conception as here, its distribution will be very consider-
able. From the arctic seas around Franz-Joseph Land (Heller), the Barents Sea (Hoek), the Kara
Sea (Hansen), and off Grinnell Land (Miers) it stretches in the west down along the eastern coast
of North America (Wilson), and in the east along the Finmark (Sars) into the Norwegian Sea, and a
little into the Atlantic, as also through the North Sea along the eastern coast of England (Goodsir),
and to the east quite into the Skager Rack and the Cattegat.

9g. Nymphon longitarse Kr.
Nymphon longitarse Kroyer, Kundsk. Pycnog., 1844, p. 112.
— — Idem, Gaimard, Voy. Scand. Lappon., 1849, Pl. 36. Fig. 2 a-f.
— — Wilson, Syn. Pycnog. New-Engl., 1878, p. 19. Pl. VII. Fig. 2, a-h.
— — Sars, Pyenogonidea, 1891, p. 75. Pl. VII. Fig. 3, 3 a-h.

Occurrence. The Ingolf-station 29 gives it to be taken in the Davis Strait close to the
western coast of Greenland, at a depth of 68 fath.

Further it is found at the Zoological Museum from the following localities: Baffin’s Bay 72°
40' Lat. N. 57° 15’ Long. W., 118 fath. («Fylla», Holm); 69° 54’ Lat. N. 55° 34’ Long. W., 50 fath. (idem),
and from the Davis Strait, along the western coast of Greenland till Igaliko (K. J. V. Steenstrup), and
Frederikshaab (Lundbeck).

Distribution. Sars, lc. p. 78, states it as occurring at Greenland (that is the western coast,
Kroyer), the Barents Sea (Hoek), the eastern coast of North America (Wilson), and the eastern
coast of England (Hoek), as he also himself has it from the whole Norwegian coast and from the

Kara Sea.

to. Nymphon Groenlandicum un. sp.

Pl. III. Fig. 14—22.
Corpus sat gracile.

Collum breviusculum.

Tuber oculare altum, obtusum, angulis acutis; ocelli permagni, subovales, subsequales, tum in medio
tum in lateribus contingentes.

Segmentum caudale breviusculum, in obliquum erectum.

Chelifori sat longi, graciles, scapo quam chela longiore, chela longiuscula, palma quam pollice multo
breviore.

The Ingolf-Expedition. III. 1. ‘ 6

42 PYCNOGONIDA.

Palpi sat longi, articulis binis ultimis gracilibus, conjunctis articulo tertio manifeste longioribus, articulo
ultimo quam pzenultimo multo breviore.

Pedes oviferi sat longi, ungue multidentato.

Pedes gressorii breviusculi, sat graciles, articulis tarsalibus conjunctis dimidiam longitudinem articuli
alterius tibialis manifeste longioribus, articulo altero tarsali quam priore multo longiore, utroque
serie aculeorum gracilium sat longorum in margine interiore instructo. Unguis longiusculus,
crassiusculus, unguiculis auxiliaribus gracilibus, brevibus, non tertiam partem longitudinis unguis
explentibus.

Long. tota 7,5™™. Rostri 2,3™™. Corporis 4™™. Segmenti caudalis 1,2™™.

The trunk rather slender.

The neck somewhat short.

The oculiferous tubercle high, truncate, with sharp corners; the ocelli very large, almost oval, of
about the same size, touching each other in the middle and at the sides.

The caudal segment somewhat short, directed obliquely upward.

The chelifori rather long, slender, the scape longer than the chela; the chela rather long, the palm
much shorter than the movable finger.

The palps rather long, the two last joints slender, together distinctly longer than the third joint, the

last joint much shorter than the last but one.

The ovigerous legs rather long, the claw with many teeth. Organ of sense, see fig. 20a.

The ambulatory legs somewhat short, rather slender,. the tarsal joints together distinctly longer than
half the second tibial joint, the second tarsal joint much longer than the first one, both with a
series of slender, rather long thorns in the inner edge. The claw somewhat long and thick .
with slender, short auxiliary claws, not reaching to a third part of the length of the claw itself.

Total length 7,5™". The proboscis 2,37". The trunk 4™™. The caudal segment 1,2™™.

Occurrence. The Ingolf-station 27, the Davis Strait, 64° 54’ Lat. N. 55° 10’ Long. W., 393 fath.

soft, gray clay, numerous pebbles, mostly granite; bottom temperature 3°8. Numerous specimens.

11. Nymphon elegans Hans.

Nymphon elegans Hansen, Kara-Hay. Pycnog., 1886, p. 11. Tab. XVIII. Fig. 4, 4 a-d.
— — Sars, Pycnogonidea, 1891, p. 86. Pl. IX. Fig. 1, 1 a-g.

Occurrence. The Ingolf-stations 15, 116, 126, and 138 show it to be taken in the Denmark
Strait, the Greenland Sea, and the western part of the Norwegian Sea from Jan Mayen some way to
the south, at a depth from 293—471 fath.

From the collections of the Zoological Museum may be added: Baffin’s. Bay 72° 40’ Lat. N. 57° 15
Long. W., 118 fath., the bottom clay without algz («Fylla», Holm); the Denmark Strait, 63° 15’ Lat. N.
25° 20’ Long. W., 270 fath. (Wandel); and the Norwegian Sea, 61° 23’ Lat. N. 4° 21’ Long. W., 505 fath.,

ooze (idem).

PYCNOGONIDA. 43

Distribution. The species is rather widely spread; it was first known from the Kara Sea
(Hansen), but is found to the south far down in the Norwegian Sea, and to the west it has been

taken quite up in the Baffin’s Bay.

12. Nymphon leptocheles G. O. Sars.

Nymphon leptocheles Sars, Pycnog. bor. arct., 1888, p. 348.
— — Idem, Pycnogonidea, 1891, p. 78. Pl. VIII. Fig. 1, 1 a-1.

Occurrence. The Ingolf-stations are: 7, 36, and 138; accordingly it is taken in the southern
part of the Atiantic, towards Iceland, and in the Davis Strait; the depths from 362—600 fath.

Distribution. The species had hitherto only been taken by Sars, chiefly along the western
coast of Norway until Lofoden, and in the sea between the Finmark and Beeren Eiland, Pycnogonidea,
1891, p.80, so that the Ingolf shows it to be considerably wider spread as well to the south as

to the west.

13. Nymphon macrum Wils.

Nymphon macrum Wilson, Pycnog. New-Engl. Adjac. Wat., 1878, p. 487, Pl. IV. Fig. 21—23.
— “= Sars, Pyenogonidea, 1891, p. 89. Pl. IX. Fig. 2, 2 a-g.

Occurrence. The Ingolf-stations are: 25, 27, 32, 33, 35, 81, all in the Davis Strait and the
northernmost part of the Atlantic, S.W. of Iceland. The depths were most frequently between 318
and 582 fath.

Previously it was found at the Zoological Museum from the Denmark Strait, 66° 20’ Lat. N.,
25° 12’ Long. W., 96 fath. (Wandel).

Distribution. Sars thinks the species to be originally arctic, because, besides occurring
between the Finmark and Beeren Eiland, it has also been taken at the eastern coast of North America
(Wilson); with this statement agrees also its occurrence in the Denmark Strait and the Davis Strait,

from where it has passed a little towards the south, into the Atlantic.

14. Nymphon macronyx G. O. Sars.

Nymphon macronyx Sars, Predr. Crustac. Pycnog., 1877, p. 365. n° 3.
a Hansen, Kara-Hav. Pycnog., 1886, p. 13. Tab. XVIII. Fig. 6, 6 a-c.
Cheetonymphon macronyx Sars, Pycnogonidea, 1891, p. 111. Pl. XII. Fig. 2, 2 a-k.

Occurrence. The Ingolf-stations are: 2, 4, IOI, 103, 105, 116, 138, 139, 140, 141, all situated
inside the southern and western parts of the Norwegian Sea, from the Faréde Islands quite to Jan
Mayen. The depths were 262—702 fath. It was found in great numbers, most frequently together
with NV. robustum.

Distribution. The species is found widely spread, from the Kara Sea down along the coast
of Norway to the Faréde Islands, but hitherto it has not been taken farther west than the western

part of the Norwegian Sea.
6*

44 PYCNOGONIDA.

15. Nymphon spinosum Goods.

Nymphon spinosum Goodsir, Spec. Pycnog., 1842, p. 139. pl. 3. fig. 3.
— — Idem, Spec. Gen. Char. Arach. Crust. 1844, p. 3. pl. I. fig. 17—18.
Chztonymphon spinosum Sars, Pycnogonidea, 1891, p. 107. Pl. XI. Fig. 3, 3 a-i.
Nymphon hirtipes Bell, Account Crust. 1855, p. 403. Pl. XXXV. Fig. 3.
_ — Wilson, Syn. Pyenog. New-Engl., 1878, p.22. Pl. V. Fig.2. Pl. VI. Fig 2 a-k.
-- — Hansen, Kara-Hav. Pyenog., 1886, p. 5 (159).
Chzetonymphon hirtipes Sars, Pycnogonidea, 1891, p. 103. Pl. XI. Fig. 2, 2 a-k.

The species is somewhat variable, but I find no sufficient reason to divide the forms belonging
hither into two species, as has been done by Sars, even if I have to acknowledge that most of the
found and examined specimens tolerably well or decidedly can be said to belong either to the WV.
spinosum of Sars, or to his WN. hirtipes, as these species are diagnosticated and described in his last,
large, and excellent work. Perhaps I may also here be permitted to state my opinion that Sars may
be said generally to be too much inclined to form new and many species and genera inside the Ar-
thropoda, whether it be Crustacea or Pycnogonida, which for the rest have been studied and drawn
by him in so excellent a manner. That such a different view of the species and the genus cannot
be referred to a less successful representation in words or in figures, and that the dispute cannot be
decided by «original specimens», will already be shown by the circumstance, that our museum by the
liberality of Professor Sars is possessed of several such critical specimens, that have been determined
by him, and that nevertheless my uncertainty and doubt of the goodness of the species have not
been removed. :

Occurrence. The Ingolf-stations are: 4, 9, 15, 25, 27; 32) 35) 51; 53) 54; 78, 87, 93, 98, 127, 144. _
This great number of stations shows it to be a widely spread species, mostly, however, to the south,
in the southern part of the Norwegian Sea, and the northern part of the Atlantic, and into the Den-
mark Strait to 66° 18’ Lat. N.; also, however, in the Greenland Sea, a little north of Iceland, and in
the Davis Strait to 65° 57' Lat. N. 55° 30’ Long. W. The depths were mostly from ca. 300 to ca. 800
fath., in a few instances between ca. 70 and ca. 140 fath., and rarely the water was so low as 35
and 44 fath.

From the collections of the Zoological Museum the following stations may furthermore be
added: the Davis Strait, 66° 49' Lat. N. 66° 28’ Long. W., 285 fath. (Wandel); 66° 32’ Lat. N. 55° 34’ Long. W.
100 fath. («Fylla», Holm); 65° 27’ Lat. N. 54° 45’ Long. W., 670 fath. (Wandel); 64° 57’ Lat. N. 55° 14’ Long. W.,
426 fath. (idem); the Denmark Strait, 64° 42’ Lat.N. 27° 43’ Long. W., 426 fath. (idem); 65° 39’ Lat. N.
28° 25’ Long. W., 553 fath. («Fylla», Ryder); the Greenland Sea in Scoresby Sound (Deichmann); the
Gaaseland Bay in the Denmark Island, 5 fath. (Bay); Angmagsalik, 11 fath. (idem); 69° 25’ Lat. L. 20° 1’
Long. W., 167 fath. (idem); 71° 21’ Lat. N. 8° 25’ Long. W. 160 fath. (Deichmann); 72° 25' Lat. N. 19° 33/
Long. W. 140 fath. (idem); 72° 26' Lat. N. 19° 35’ Long. W., 105 fath. (idem); 72° 53’ Lat. N. 20° 36’ Long. W.,
96 fath. (idem). Besides we have it from the Farée-Shetland Channel 61° 23’ Lat. N. 5° 4' Long. W.,
255 fath. (Wandel), and from the Skager Rack, the «Tromlinger» to N. W. 3/,N. 38 miles, 300 fath.
(Joh. Petersen).

oS

PYCNOGONIDA. 45

Distribution. The species is circumpolar, and besides it follows as well the American as
the European shores far southward, thus being one of the most widely spread and most common

Pycnogonida on deep water.

16. Nymphon tenellum G. O. Sars.

Nymphon tenellum Sars, Pycnog. bor. arct., 1888, p. 353.
_ Idem, Pycnogonidea, 1891, p. 109. Pl. XII. Fig. 1, 1 a-h.

Occurrence. The Ingolf-stations are: 7, 28, and 44, showing it to be found in the northern-
most part of the Atlantic and in the south of the Davis Strait in depths from 420 to 600 fath.

Distribution. The species had hitherto only been found by Sars in the sea off the Fin-
mark, and consequently this author took it to be a genuine arctic form; the three stations given here,

carry the species much farther south and west, always on very deep water.

17. Nymphon robustum Bell.
PL III. Fig. 23—24.
Nymphon robustum Bell, Account Crust. 1855, p. 409. Pl. XXXV. Fig. 4.
Chzetonymphon robustum Sars, Pycnogonidea, 1891, p.115. Pl. XII. Fig. 3, 3 a-d.
Nymphon hians Heller, Crust. Pycnog. Tunic. 1875, p. 41. Tab. V. Fig. 3—5.

The species varies very much, especially as to size; thus a grown male has measured 23™",
and an unripe female 19,5™™, while on the other hand grown males of 11™™ are not rarely met. These
differences for a long time induced me to suppose two or more species to be hidden under the old 4.
robustum, and so I began to study the several small and large specimens in their mutual contrast,
and thought in the armature of the fourth and fifth joints of the ovigerous legs of the male to have
found a sure criterion. I had, however, soon to give up the thought of the systematic importance of
this armature; but nevertheless I have partly rendered it here in pl. III, fig.23 and 24, as it seemed
to me to give a good idea of the powerful development and the different shapes and positions as-
sumed by the bristles of the legs for the attaching of the eggs and young; it is, however, also to
be remembered that WV. vobustum is likely to be the Pycnogonid, on the male of which the young
are most firmly attached, and cling for the longest time.

Occurrence. The Ingolf-stations are: 3, 4, 15, 41, IOI, 103, 105, I15, 116, 126, 138, 139, 140, 141,
143. According to this series of stations it has most frequently been taken in the west and south
parts of the Norwegian Sea, and some way into the Atlantic; single specimens have been taken in
the Greenland Sea and the Denmark Strait. The depths were mostly between 300 and 800 fath., only
once below 100 fath. viz. 86 fath.

‘In the Zoological Museum it is found from the Greenland Sea: 70° 26' Lat. N. (Deichmann);
72° 26' Lat. N. 19° 35’ Long. W., 105 fath. (idem); 72° 53’ Lat. N. 20° 36’ Long. W., 96 fath. large stones
(idem); Scoresby Sound 3—25 fath. (idem); from the Davis Strait, 66° 16’ Lat. N. 25° 20’ Long. W., 327

46 PYCNOGONIDA.

fath. (Wandel). Further we have it also farther south than the Ingolf-stations, viz. in the Fardée-
Shetland Channel, 61° 23' Lat. N. 4° 21’ Long., 505 fath. (idem). |

Distribution. This species is widely spread, as well far to the north, from the arctic North
America (Bell), Discovery Bay (Miers), Franz-Joseph Land (Heller), and in the Kara Sea (Hansen), as
also so far to the southward as 60° Lat. N.

2. Gen. Paranymphon Caull.
Paranymphon Caullery, Pycnogonides, 1896.

Corpus glabrum.

Processus corporis perlongi.

Chelee resupinatee, subinermes.

Palpi septem-articulati.

Pedes oviferi octo-articulati, ungulati.

Pedes gressorii absque unguiculis auxiliaribus.

The trunk smooth.

The processes of the trunk very long.

The chela bent backwards, the teeth weak and few.
The palps seven-jointed.

The ovigerous legs eight-jointed, provided with claws.

The ambulatory legs without auxiliary claws.

Caullery, lc. p.361 has founded the genus on one single characteristic, viz. the number of
joints in the palps, which number, however, is wrongly given as 6 instead of 7. As moreover no
real diagnosis has been given either of the genus or the species, I have thought it necessary to give
such, but also to point out that, only one species of the genus being known, it will be difficult always

_ to determine, which characteristics are to be regarded as generic, and which as specific ones.

Paranymphon spinosum Caull.
PLIV. Fig. 20—28. .
Paranymphon spinosum Caullery, Pycnogonides, 1896, p. 361. Pl. 12. Fig. 1r—6.

Corpus subrobustum.

Processus corporis perlongi, admodum discreti, in cornua alta, acuta, erecta ad finem producti.
Rostrum breve, nutans.

Tuber oculare peraltum, gracile, attenuatum, recurvum, absque ocellis.

Segmentum caudale permagnum, altissimum, erectnm, paulum curvatum.

Palpi breves, articulis quaternis ultimis brevibus, longitudine sensim decresentibus.

PYCNOGONIDA. 47

Pedes oviferi breves; pars terminalis pedum lamellis paucis cultriformibus armata; unguis permagnus,
dentibus paucis armatus.

Pedes gressorii breviusculi, articulo altero tarsali quam priore vix breviore. Unguis tenuis, simplex,
dimidiam partem articuli alterius tarsalis superans.

Long. tota 2™™. Rostri 0,25™™. Corporis 1,75™™. Segmenti caudalis 1,2™™.

The trunk somewhat clumsy.

The side-processes of the trunk very long, much separated, with high, pointed, horn-shaped processes.

The proboscis short, directed obliquely downward.

The oculiferous tubercle very high, slender, bent backward, without ocelli.

The caudal segment very large, erect, a little curved.

The palps short, the four last joints short, by degrees decreasing in length.

The ovigerous legs short; the terminal part with few, knife-shaped leaves. The claw very large, with
few teeth.

The ambulatory legs rather short, the second tarsal joint scarcely shorter than the first. The claw
fine, without auxiliary claws, longer than half the length of the second tarsal joint.

Total length 2™. The proboscis 0,25™™. The trunk 1,75™™. The caudal segment 1,2™™.

The habitus figure of Caullery is so rough and so bad, his characters as well of the genus
as the species so poor, and besides, I think, partly useless or impossible, so that one is strongly
tempted to pay no regard to the species here made by him; as, however, on the other hand, his
species is so characteristical, and in-several essential characteristics agree with the form represented
here, I have thought the identity so probable that I have adopted his generic and specific name.
Already before I have stated as my opinion that it is incorrect to give the palps 6 joints in stead of
7; as impossible I shall briefly mention another character. In his description of the species Caullery,
1c. p. 362, mentions some clavate bristles which are said to be found on the chelifori and the other
limbs! His words run thus: «Les mandibules portent (comme les autres appendices) des soies formées
dun axe rigide légérement courbé, terminé en pointe et recouvert dans sa partie terminale d’un manchon
verdatre qui donne a ensemble une forme en massue», He moreover draws one of these bristles,
not only in pl. 12, fig. 3 and 4, but also separately, more enlarged, fig.6; but these formations are only
common bristles with a bit of mud on the end, that is to say, pure products of art.

Occurrence. ‘The Ingolf-stations are: 25 and 94. The former of these stations gives it as
taken in the Davis Strait, 63° 30’ Lat. N. 54° 25’ Long. W., 582 fath.; the bottom was soft mud with a
temperature of 3°3; about ten specimens were taken here; the latter station is in the Denmark Strait
towards the eastern coast of Greenland 64° 56’ Lat. N. 36° 19’ Long., 204 fath., sand, the bottom
temperature 4°1.

Distribution. This species was formerly only known from three specimens taken in three
places in the Bay of Biscay on depths between 950—1700". The bottom was in all three places

mud (vase), to which, of course, the mentioned and drawn wonderful bristles owed their knobs.

48 PYCNOGONIDA

2. Subfam. Pallenini.

Palpi deficientes vel imminuti.

The palps wanting or rudimentary.

1. Gen. Pallene (Johnst.).

Pallene Wilson; Syn. Pycnog. New-Engl., 1878.
Sars, Pycnogonidea, 1891.

1. Pallene acus n. sp.

PLIV. Fig. 8—13.
Corpus subgracile.

Collum breve.

Rostrum crassum.

Tuber oculare altum, acutissimum, erectum, paulum curvatum, absque ocellis.

Segmentum caudale magnum, in obliquum erectum.

Pedes oviferi longi; pars terminalis pedum laminis latis, ovalibus 10—12 instructa.

Pedes gressorii longi, articulo altero tarsali in margine interiore acie angusta, longa instructo. Unguis
permagnus, validus, quartas partes articuli alterius tarsalis fere explens, unguiculis auxiliaribus
gracilibus, tertiam partem longitudinis unguis fere referentibus.

Long. tota 3™™. Rostri 0,65™™. Corporis 2,2™™. Segmenti caudalis 0,5™™.

The trunk rather slender.

The neck short.

The proboscis thick.

The oculiferous tubercle high, very pointed, erect, a little curved, without ocelli.

The caudal segment large, obliquely erect.

The ovigerous legs long; the terminal part with 10 to 12 broad, oval leaves.

The ambulatory legs long, the inner edge of the second tarsal joint with a long, narrow cutting-blade.
The claw very large, powerful, about four fifths of the length of the second tarsal joint, with
slender auxiliary claws, of about one third of the length of the claw.

Total length 3™™. The proboscis 0,65™". The trunk 2,2™. The caudal segment 0,5™™.

The cutting edge or blade (acies) that in this species and the following one is mentioned as
proceeding from the inner margin of the second tarsal joint, corresponds to a similar formation on
the same tarsal joint in Phoxichilidium petiolatum, which is drawn by Hansen, Zoolog. Dan., 1885,
pl. VU, fig. 22 cc, and in the explanation of the figures, p.IX, called «a cutting edge on the lower
margin of this»; in the text, p.130, it is called «<a cutting ridge formed like the blade of a knife».

PYCNOGONIDA. 49

The same edge is later mentioned in the same Pycnogonid by Sars, Pycnogonidea, 1891, p. 26, as «an
undivided lamella», cp. pl. II, fig.2h. The edge is undivided, but in this species and the following
one it is supported by a series of thickenings or ridges, running parallel and somewhat obliquely
from the inner side outward, comp. my fig., pl. IV, fig.13, and with regard to the following species
fig. 18 and 19.

Occurrence. The Ingolf-station 24, in the Davis Strait, 63° 06' Lat. N. 56° 00’ Long. W., 1199
fath.; the bottom bluish-gray, soft mud, the temperature 2°4. About ten specimens were taken here.

2. Pallene hastata n. sp.

PLIV. Fig. 14—19.
Corpus subgracile.

Collum longum.

Rostrum crassum.

Tuber oculare altum, acutissimum, erectum, paulum curvatum, absque ocellis.

Segmentum caudale breve, crassiusculum, in obliquum erectum.

Pedes oviferi longi; pars terminalis pedum laminis latis, ovalibus 10—11 instructa, in articulo tertio
organum sensile (auditorium?) perspicuum; in margine articuli quarti exteriore sete pauce
curvatee (3?).

Pedes gressorii longi, articulo altero tarsali in margine interiore acie angusta, longa instructo. Unguis
magnus, validus, tres partes articuli alterius tarsalis fere explens, unguiculis auxiliaribus gracilibus,
quintam partem longitudinis unguis fere explentibus.

Long. tota 3,7™™. Rostri 0,84™™. Corporis 2,5™™. Segmenti caudalis 0,42™™.

The trunk somewhat slender.

The neck long.

The proboscis thick.

The oculiferous tubercle high, extremely pointed, erect, a little curved, without ocelli.

The caudal segment short, somewhat thick, obliquely erect. :

The ovigerous legs long, the terminal part with 10 to 11 broad, oval leaves; in the third joint is the
organ of sense (ear?) transparent; in the outer edge of the fourth joint some few, curved

bristies (3 ?).

The ambulatory legs long, the inner edge of the second tarsal joint with a long, narrow cutting blade.
The claw large, powerful, of about three fourths of the length of the second tarsal joint, with
slender auxiliary claws of about one fifth of the length of the claw.

Total length 3,77". The proboscis 0,84™™. The trunk 2,5". The caudal segment 0,42™".

With regard to the sensorium, fig. 17a, I must refer to the foregoing.

Occurrence. The Ingolf-station 36 gives the species as taken in the southern part of the
Davis Strait, 61° 50’ Lat. N. 56° 21’ Long. W., 1435 fath., the bottom gray mud, with a temperature of
1°5. About ten specimens were taken.

The Ingolf-Expedition. IIL 1.

50 PYCNOGONIDA.

2. Gen. Cordylochele G. O. Sars, 1888.
Cordylochele Sars, Pycnog. bor. arct., 1888.

1. Cordylochele malleolata G. O. Sars.

Pallene malleolata Sars, Crust. Pycnog., 1880, p. 460.
Cordylochele malleolata Sars, Pycnogonidea, 1891, p. 45. PL IV. Fig. 1, 1 a-k.

Occurrence. The Ingolf-stations are: 4, 9, 32, 126, that is to say the southern part of the
Norwegian Sea, the Greenland Sea, the Denmark Strait, and far up in the Davis Strait. The depths
were between 200 and 300 fath.

Distribution. According to Sars, Pycnogonidea, 1891, p. 48, it is a genuine arctic form,
from the Kara Sea, Spitzbergen, and Beeren Eiland. By the Ingolf it was taken somewhat farther

south and west.

2. Cordylochele longicollis G. O. Sars.

Cordylochele longicollis Sars, Pyenog. bor. arct., 1888, p. 344.
— _ Idem, Pycnogonidea, 1891, p. 49. PIL IV. Fig. 2, 2 a-g.

Occurrence. The Ingolf-stations 27 and 73 show it to be taken in the Davis Strait and
in the Atlantic S.W. of Iceland. The depths were between 400 and 600 fath.

Distribution. Hitherto the species was only known from the coasts of Norway and Lofoden.

3. Gen. Pseudopallene Wils., 1878.
Pseudopallene Wilson, Syn. Pycnog. New-Engl., 1878, p. 10.

Pseudopallene circularis Goods.

Pallene circularis Goodsir, New spec. Pycnog., 1842, p. 137. pl. 3. fig. 2.
Pseudopallene circularis Sars, Pycnogonidea, 1891, p. 38. Pl. III. Fig. 3, 3 a-h.
Pallene intermedia Kroyer, Kundsk. Pycnog., 1844, p. 119 (full-grown).

— -— Idem, Gaimard, Voy. Scand. Lappon., 1849, Pl. 37. Fig. 2, 2 a-l.
Pseudopallene intermedia Hansen, Kara-Hav. Pycnog., 1886, p. 21. Tab. XIX. Fig. 2, 2 a-l.
Pallene discoidea Kroyer, Kundsk. Pycnog., 1844, p. 120 (young).

-- o= Idem, Gaimard, Voy. Scand. Lappon., 1849, Pl. 37. Fig. 3, a-g.
Pseudopallene discoidea Wilson, Syn. Pycnog. New-Engl., 1878, p. 12. PL III. Fig. 3, a-b (young).
Pseudopallene hispida (Stimps.) Idem, Syn. Pycnog. New-Engl., 1878, p. 10. Pl. III. Fig. 1 a-e (full-grown).

Occurrence. The Ingolf-station 127, i.e. the Greenland Sea, North of Iceland, 66° 33' Lat. N.
20° 05' Long. W., depth 44 fath.

PYCNOGONIDA. 51

Besides the stations mentioned by Hansen, l.c, p.23, from the south-western coast of Nova
Zembla, the western coast of Greenland, the Finmark, and Kullen, it is found in the Zoological
Museum also from the Davis Strait 65° 35’ Lat. N. 54° 50’ Long. W., 80 fath. (idem); the belt of rocks
and islands outside Frederikshaab, 25 fath. (idem, and Lundbeck); in the Bredebugt (the Denmark
Strait) 9 fath. (the lieutenant Jensen); in the Ofjord (the Greenland Sea) 15 fath. («Diana»).

Distribution. The species is one of the most widely spread Pycnogonida, from the arctic
seas quite down into the Sound, and towards the west from the Davis Strait along the eastern coast
of America; it keeps, however, mostly nearer to the coast, and the depths are most frequently small,

rarely more than 100 fath.

3. Gen. Pallenopsis Wils., 1880.
Pallenopsis Wilson, Report Pycnog. «Blake», 1880.

Pallenopsis plumipes n. sp.

PL. IV. Fig. 1—7.
Corpus sat robustum, glabrum.

Collum vix ullum.

Rostrum longum, percrassum, obconicum, ante medium manifeste constrictum.

Tuber oculare parum altum, tumidum, apice obtuso, recurvo, tuberculis minimis scabroso; ocelli parvi
rotundi, maculis pigmentariis permagnis.

Segmentum caudale gracillimum, productum, subcylindricum, ad apicem vix clavatum, in obliquum |
erectum.

Chelifori sat longi, graciles, scapo manifeste bipartito; digiti longiusculi, graciles, sat hiantes, inermes.

Palpi breves, solidi, acuminati.

Pedes oviferi breves, absque ungue; pars terminalis pedum absque laminis.

Pedes gressorii longi, longitudinem totam quater explentes, sat graciles, articulo priore tibiali pro parte,
altero toto binis seriebus setarum longarum natatoriarum instructis. Unguis minus productus,
sat gracilis, unguiculis auxiliaribus brevibus, gracillimis.

Long. tota 29™™. Rostri 9™™. Corporis 13™™. Segmenti caudalis 7™™.

The trunk rather plump, smooth.

The neck scarcely conspicuous.

The proboscis long, very thick, obconical, before the middle distinctly constricted.

The oculiferous tubercle not high, swollen, the point rounded, bent backwards, roughened by very
small knobs; the ocelli very small, round, the coloured spots very large.

The caudal segment very slender, very long, almost cylindrical, slightly clavate towards the point,

obliquely erect.
7

52 PYCNOGONIDA.

The chelifori rather long, slender, the scape distinctly two-jointed, the fingers rather long, slender,
somewhat gaping, without teeth.

The palps short, unjointed, tapering.

The ovigerous legs short, without claw; the terminal point without dermal leaves.

The ambulatory legs long, four times the total length, rather slender, the first tibial joint partly, the
second one in the whole length provided with two series of long natatory bristles. The claw
not very long, rather slender, with short, very slender auxiliary claws.

Total length 29™™. The proboscis 9™™. The trunk 13™™. The caudal segment 7™™.

Occurrence. The Ingolf-station 47, in the north-eastern Atlantic, 61° 32’ Lat. N. 13° 40’ Long. W.
depth 950 fath. The bottom gray clay with Globigerina shells and a temperature of 3°23. One

single female.

For elucidating the genus Padlenopsis, and the species of Kroyer Pall. fluminensis that has
been much discussed, I shall here, relying on the original specimen of the museum, give some par-

ticulars, starting with a new diagnosis of the species.

Pallenopsis fluminensis Kr.
Pl. V. Fig. 1—6.

Phoxichilidium fluminense Kroyer, Kundsk. Pycnog., 1844, pp. 104 and 124. Tab. I. Fig. 1, a-f.
ee — Hoek, Report Pycnog. «Challenger», 1881, p. 81. Pl. XIV. Fig. 1-4.
Pallene fluminensis Semper, Pycnog. Larvenf., 1874, p. 282.
— — Bohm, Pycnog. Berl. 1879, p. 180. Tab. I. Fig. 4, 4 a-f.
Pallenopsis fluminensis Wilson, Report Pycnog. «Blake», 1882; p. 250.
_- a Schimkéwitsch, Pantop. «Vettor Pisani», 1890, p. 14 (339). Fig. 24-31.

Corpus sat robustum, glabrum.

Collum perbreve.

Rostrum breviusculum, crassiusculum, in medio vix constrictum.

Tuber oculare sat altum, erectum, subconicum, ad apicem paulum attenuatum; ocelli perparvi, rotundi.

Segmentum caudale crassiusculum, minus productum, in obliquum erectum.

Chelifori breviusculi, sat robusti, scapo subsolido, egerrime partito; digiti perbreves, crassi, vix hiantes.

Palpi perbreves, solidi, obtusi. .

Pedes oviferi breves, absque ungue.

Pedes gressorii breviusculi, crassiusculi; ductus glandarius in articulo quarto maris brevis. Unguis sat
brevis atque robustus, unguiculis auxiliariis sat robustis, dimidiam longitudinem unguis paulum
excedentibus.

Long. tota 7,1™. Rostri 1,7™™. Corporis 4,3™™. Segmenti caudalis 2™™,

PYCNOGONIDA. 53

The trunk rather clumsy, smooth.

The neck very short.

The proboscis very short and thick, scarcely constricted in the middle.

The oculiferous tubercle rather high, erect, almost conical, a little tapering to the top; the ocelli very
small, round.

The caudal segment somewhat thick, not very long, obliquely erect.

The chelifori somewhat short, rather clumsy, the transverse partition of the scape scarcely visible; the
fingers very short, scarcely gaping.

The palps especially short, unjointed, truncated.

The ovigerous legs short, without claws.

The ambulatory legs somewhat short and thick, the gland duct on the fourth tarsal joint of the male
short. The claw rather short and clumsy, with rather clumsy auxiliary claws of a little more
than half the length of the claw.

Total length 7,1™". The proboscis 1,7™™. The trunk 4,3™™. The caudal segment 2™™.

One single male taken in the port of Rio de Janeiro, and brought home by Kroyer; it is
still found in the museum.

Kroyer, l.c. pp. 104 and 124, established this species as a Phoxichilidiwm, and gave also draw-
ings of the animal, as well as some particulars; but Kroyer was no skilful drawer, and in this in-
stance he was especially unfortunate; and as, moreover, Kroyer, contrary to his common accuracy,
has made some essential errors by failing to see, it will be understood, that uncertainty might easily
arise as to the interpreting of this species of his. It will therefore be of some interest to get a
new description of the species, and it is only to be regretted that the original specimen has been
treated so badly by being used for representation. That notwithstanding the errors and representation
of Kroyer the divinations hitherto seem to have been correct, will not be of any importance so as
to prevent a future author in putting up (and, as it would seem, in rightly doing so) the species of
Kroyer as a type of a new genus.

Kroyer, as we have seen, referred the species to the Phoxichilidium of Milne-Edwards, of
which genus he, lc. p. 121, gave a copious description in Latin, which description was to comprise

all the species of the genus known to him. In this description the chelifori are mentioned in the

following manner: «Mandibule.... maximze sunt (dimidiam animalis longitudinem fere zquantes), ex
articulo composite basali, chelaque breviore» — accordingly only one joint in the scape. Of the
palps it is said: «Maxille prioris paris desunt — accordingly the palps are wanting. From the

specific description may be pointed out that the ovigerous legs, lc. p.124, are said to be tenjointed,
from which the inference may be drawn that the animal has been full-grown, and further it may be
noticed that the bristles on the ambulatory legs are not mentioned, from which fact we may securely
conclude that the specimen of Kroyer has had no specially conspicuous bristles, or, at all events,
that Kroyer has not observed this peculiarity which was otherwise well known to him, and which
he has often mentioned and described in the sea-Arthropoda examined by him. (I have in vain searched

for such feathery bristles, comp. Bohm Lec. p.182, PILI, fig.4 {). Finally Kroyer has not men-

54 PYCNOGONIDA.

tioned, much less drawn the gland ducts (ductus glandarii), really found in his original specimen.
With regard to the figures it has to be pointed out that neither in fig.1a nor in figrb of Kroyer
does the scape of the chelifori show any sign of articulation, and that only in the middle of the scape
in fig.te a slight swelling is found. Further it must also be noticed that, while in the text, lc p. 106,
Kroyer gives the longitudinal relation between the fourth, fith, and sixth joints of the ambulatory legs
as 27, 27, and 51, this ratio is in fig.1f as 27, 27, and 24.

According to what has been stated here, I think that Semper, who has nothing but the re-
presentation by Kroyer to rely on, has been very bold in referring Phoxichil. fuminense to the genus
Pallene, \.c. p. 282. Neither do I think that Bohm has been justified in referring some Pycnogonids,
although they have been taken at the coasts of South America, to the Phoxichil. fuuminense of Kroyer,
at the same time referring this species to Pallene Johnst. The species described and drawn under
this appellation by Bohm, may as well be a genuine Pallene Wils., with the scape of the chelifori
undivided, and no gland duct on the ambulatory legs of the male; and even if Bohm, contrary to
the description of Kroyer, might regard Phoxichil. jluminense as a Pallene, the ratio between the
joints of the ambulatory legs is so different from the statements of Kroyer (whether regarding his
text or his figures), and the presence or absence of feathery bristles is so important a feature, that
Bohm ought to. have hesitated very much in identifying the species). Hoek draws and describes a
Phoxichil. fluminense Kr. that no doubt belongs to the genus Pallemopsis Wils., and is nearly related
to fluminense, but the description is insufficient, and the figures, especially that of the oculiferous
tubercle, fig. 2, so unlike the real Pal/. fluminenszs, that very possibly it may be another species.

Wilson, lc. p.250, refers as well the species of Kroyer as that of Bohm to his new genus
Pallenopsis, without, as it seems, to be quite clear of the uncertainty, but nevertheless I suppose that
his genus also comprises Phox. fluminense, although this latter in the one rather essential point that
by Wilson is regarded as the chief point, that is to say, the construction of the scape of the chelifori,
deviates from the characteristics of the new genus. The description and figures of Schimkéwitsch
are, like those of Hoek, insufficient, and especially the highly developed bristles, fig. 28 and 29, might
indicate another species.

According to the preceding, as well Semper as Bohm and Wilson seem to have referred
the Phox. fluminense of Kroyer correctly to the genera known and acknowledged by them, although
none of them have seen the original specimen of Kroyer, and nothwithstanding the fact, that the
representation by Kroyer is not only incomplete, but even incorrect in several, and in some of the
most essential, points. On the contrary I think the species of Bohm to be different from that of
Kroyer, and likewise I think it very uncertain that Hoek and Schimkéwitsch have had the

species of Kroyer.

Il. Fam. Ascorhynchide.

Corpus plus vel minus manifeste in segmenta partitum.

Rostrum tumidum, plus vel minus flexibile.

Pao

PYCNOGONIDA. 55

Chelifori incompleti, chela plus vel minus imminuta.
Palpi expleti.

Pedes oviferi in utroque sexu.

The trunk more or less distinctly segmented.

The proboscis swollen, more or less movably articulated.

The chelifori defectively developed, the chela more or less rudimentary.
The palps well developed.

Ovigerous legs present in both sexes.

_. Gen. Ascorhynchus G. O. Sars.
Ascorhynchus Sars, Prodr. Crust. Pycnog., 1877.

Referring in all essentials to the generic diagnosis of Sars, such as he has given it in his
principal work on the Pycnogonids, Pycnogonidea, 1891, p.132, I must, however, on account of an
observation by the examination of these animals, wish to have it altered a little. By examining a
full-grown female I found that this specimen had long fingers with an equal development of both;
the whole chela, however, was somewhat shrivelled, and the fingers relatively much thinner, not only
than in other Pycnogonida, but also thinner than in earlier stages of the same species, so that the
whole chela gets a somewhat rudimentary appearance, cp. my figure, pl. V, fig.13. This observation

also influences the family-diagnosis.

Ascorhynchus tridens n. sp.
PL. V. Fig. 7—18.

Corpus sat gracile, marginibus posticis annulorum corporis ipsis in apicem productis.

Collum sat breve.

Rostrum crassum, manifeste restrictum. «

Tuber oculare magnum, apice in angulum producto, dentibus lateralibus acutis.

Segmentum caudale gracile, libratum.

Chelifori breves; digiti seepissime imminuti, interdum producti, graciles.

Palpi longiusculi. Organum sensile manifestum.

Pedes oviferi longiusculi, laminis partis terminalis pedum ad basin in dentes senos magnos incisis.

Pedes gressorii breviusculi, scabrosi, dense hirti, articulo priore tarsali quam altero ter breviore, arti-
culo altero minus dense pectinato, articulo quarto pedum trium parium posteriorum solummodo
nodulo armato.

Long. tota (rostro porrecto) ro™. Rostri 4™™. Corporis 5™. Segmenti caudalis 1,6™™.

56 PYCNOGONIDA.

The trunk rather slender, the posterior edge of the rings produced into a pointed tooth.

The neck rather short.

The proboscis thick, distinctly constricted.

The oculiferous tubercle large, the apex produced into an angle, the side-teeth sharp.

The caudal segment slender, perpendicularly erect.

The chelifori short; the fingers mostly rudimentary, sometimes long, slender.

The palps somewhat long. Sensory distinct.

The ovigerous legs somewhat long; the dermal leaves of the terminal part with 6 strong teeth at
the base.

The ambulatory legs somewhat short, rough, densely hairy, the first tarsal joint three times shorter
than the second one, the comb of the second joint less small-toothed, only the fourth joint of
the three hindmost pairs of legs with a tubercle.

Total length (with the proboscis produced) 1o™, ‘The proboscis 4™™. The trunk 5™. The caudal

segment 1,6™™.

This species is very much like Ascorhynchus abyssi of Sars «Pycnogonidea, 1891, p. 133, pl. XIV,
fig. 2, 2 a-t, and I was long doubtful whether I should set it up as a particular species. Among the
characters of the diagnosis I may especially point to the shape of the oculiferous tubercle, having
always found its dorsal side produced in the middle to an acute angle with sharp teeth on the sides.
The neck is also much shorter, the point of the rings of the trunk is drawn back quite to the
posterior edge, the caudal segment is horizontal, not directed downward, and the armament of the
inner edge of the second tarsal joint is much more spread than in Ascorhynchus abysst. I have also

pointed out that the sensory in the palps is distinctly discernible, and that only the three hindmost

pairs of ambulatory legs have the tubercle on the fourth joint, already represented by Sars; but it is

possible or probable that these two characters may be found also in Ascorhynchus abysst. Finally
the ratio of length between the joints of the palps is not a little different from that in the species
of Sars. The differing structure of the chela and its fingers is scarcely to be regarded as a specific
character.

Occurrence. The Ingolf-stations 112, 113 and 124 are in the western part of the Norwegian
Sea and in the southeastern part of the Greenland Sea. The two first places, on which it was taken
in considerable numbers, were on 67° 57' Lat. N. 6° 44' Long. W., and 69° 31’ Lat. N. 7°06’ Long. W., the
depths were 1267 and 1309 fath., and the bottom was on both places Biloculina clay with tempe-
ratures of + 1°r and +1°. On the third place, 67° 40’ Lat. N. 15° 40’ Long. W. the depth was only
495 fath., the bottom brownish gray, or blue mud or clay (not Biloculina clay) with short, cylindrical,

araneous foraminifera, and with a temperature of + 0,6°.

Ill. Fam. Colossendeide.

Corpus solidum.

Rostrum validum, inflexibile, libratum vel nutans.

\

PYCNOGONIDA. 57

Chelifori deficientes (in larvis interdum chelifori scapo bipartito prediti).
Palpi expleti.
Pedes oviferi in utroque sexu.

The trunk not divided into segments.

The proboscis colossal, inflexible, horizontal, or directed obliquely downward.
Chelifori wanting (in the larvae sometimes chelifori with two-jointed scape).
The palps well developed.

Ovigerous legs present in both sexes.

Gen. Colossendeis Jarz. 1870.

Colossendeis Jarzynsky, Prem. cat. Pycnog., 1870.

t Colossendeis proboscidea Sab.
Phoxichilus proboscideus Sabine, Mar. invert. anim., 1824, p. CCXXVI.
Colossendeis proboscidea Hoek, Pycnog. «Willem Barents», 1881, p. 22. Pl. Il. Fig. 41-42.
— == Hansen, Kara-Hav. Pycnog., 1886, p. 20.
= — Sars, Pycnogonidea, 1891, p. 138. Pl. XV. Fig. 1, 1 a-d.
Colossendeis borealis Jarzynsky, Preem. cat. Pycnog., 1870.
Anomorhynchus Smithii Miers, Coll. Crust. Pycnog., 1881, p. 50. Pl. VII. Fig. 6-8.

Occurrence. The Ingolf-stations 116, 124 and 139 are from the western side of the Nor-
wegian Sea up towards Jan Mayen and down towards the Farde Islands, as also in the southern
part of the Greenland Sea; the depths were 400o—7oo fath., and the bottom mud.

From the collections of the Zoological Museum may be added: the Davis Strait, 65° 27’ Lat. N.
54° 45’ Long. W., 67 fath., coral sand (Wandel), and the Norwegian Sea, off Lodmundarfjord, «Snurrevaad»
(a kind of fishing net used by Danish fishers for the fishing of plaice, by which a fishing ground is
searched all round) («Diana», Horring).

Distribution. The species is likely to be circumpolar, widely spread; it seems to have been

taken in the greatest number in the Kara Sea, reaching, however, down to 60° Lat. N.

2. Colossendeis clavata n. sp.

Pl. V. Fig. 19—20.
Corpus gracile.

Rostrum longum, crassum, bis inflatum.
Tuber oculare sat altum, ante preeceps, post declive; ocelli anteriores magni, pyriformes, posteriores
perparvi, ovales, cum margine posteriore ocellorum anteriorum emarginato contigui.

The Ingolf-Expedition. III. 1. 8

58 PYCNOGONIDA.

Segmentum caudale longum, clavatum.

Palpi breviusculi.

Pedes oviferi breves.

Pedes gressorii subgraciles, longi, articulo priore tarsali quam altero duplo longiore. Unguis parvus,
dimidiam longitudinem articuli alterius tarsalis vix excedens.

Long. tota 48™™. Rostri 24™™. Corporis 18,5™™. Segmenti caudalis 5™™.

The trunk slender.

The proboscis long, thick, swollen in two places.

The oculiferous tubercle rather high, anteriorly steep, posteriorly sloping; the foremost ocelli large,
pyriform, the hindmost ones very small, oval, lying close to the emarginate hinder edge of the
foremost eyes.

The caudal segment long, clavate.

The palps somewhat short.

The ovigerous legs short.

The ambulatory legs somewhat slender, long, the first tarsal joint twice the length of the second one.
The claw small, scarcely exceeding half the length of the second tarsal joint,

Total length 48™™. The proboscis 24™™. The trunk 18,5™™. The caudal segment 5™".

Occurrence. The Ingolf-station 64, that is the northern Atlantic south of Iceland, 62° 06’
Lat. N. 19° oo’ Long. W., 1041 fath. Bottom temperature 3°1. Only one single specimen, a full-

grown female.

3. Colossendeis colossea Wils.

Colossendeis colossea Wilson, Report Pycnog. «Blake», 1881, p. 244. Pl. I. Fig. 1. Pl. III. Fig. 5—7.
? Colossendeis gigas Hoek, Report Pycnog. «Challenger», 1881, p.61. Pl. VIII. Fig. 1—2. Pl. X. Fig. 1—5.
Nec! Colossendeis gigas (Hoek) Schimkéwitsch, Compte-rendu Pantop. «Albatross», 1893, p. 29.

I suppose the Colossendeis colossea of Wilson to be different from the Colossendeis gigas of
Hoek, and still more decidedly different from the species of the same name of Schimkéwitsch.

Occurrence. The Ingolf-stations are 11 and 18, the former being in the Denmark Strait,
64° 34’ Lat. N. 31° 12’ Long. W., 1300 fath.; the latter in the Atlantic, 61° 44’ Lat. N. 30° 29’ Long. W.,
1135 fath. Three specimens were taken, the largest of which of a length of 63™™.

Distribution. Wilson has this species from the eastern coast of North America, from
41° 33' Lat. N. to 38° 45’ Lat. N., and from 65° 47' 10” Long. W. to 73° 10' 30” Long. W. from depths
between 524—1186 fath. According to my conception of the species this species is only known from

the Ingolf, and the places stated by Wilson.

PYCNOGONIDA. 59

4. Colossendeis angusta G. O. Sars.

Colossendeis angusta Sars, Prodr. Crust. Pycnog., 1877, p. 368 n° 8.
— — Wilson, Report Pycnog. «Blake», 1881, p. 243. PLIIL. Fig.8 og 13.
— — Hoek, Pycnog. Faroe Chann. «Triton», 1884, p.5. Pl. 1. Fig. 8.
— — Hansen, Kara-Hav. Pycnog., 1886, p. 21.
— — Sars, Pycnogonidea, 1891, p. 140. Pl. XV. Fig. 2, 2 a-f.
Nec! Colossendeis gracilis Hoek, Report Pycnog. «Challenger», 1881, p.69. Pl. IX. Fig.6—8. Pl. X. Fig.6—7.
= — — Schimkéwitsch, Compte-rendu Pantop. «Albatross», 1893. p. 32.

I am decidedly of the opinion that the Col. gracilis of Hoek and the present species are
different, even if by the mutual ratio of the last joints of the palps and by the specially long
claws of the ambulatory legs they form a particular generic group. It is upon the whole only
in the imago, or a far advanced stage of the development that the last joint but two of the palps
assumes its peculiar shape, while in the very young larva the same joint, cp. fig. 22, does not deviate
as to shape and position, but only as to length from the rule.

The chelifori found by Hoek in a couple of specimens of Col. angusta and gracilis, and by
him mentioned as something quite strange or abnormal, I have found in upwards of a score of
grown young ones (of a length of 13—14™™) of Col. angusta, fig. 21, so that I should even be inclined
to suppose that the young one as a rule keeps these larval limbs, until they are thrown off at the
last moulting, cp. fig. 21. Also in a much younger larva (6™™ long) I have found chelifori of
about the length of the proboscis, and with the scape divided into two distinct joints as in the full-
grown larva. The fact of the scape being two-jointed seems to me to be of importance with regard
to the characterization and systematic position of the family, and therefore I have also pointed out
this feature in the family-diagnosis. Cp. also the essays by Hoek cited here.

Occurrence. The Ingolf-stations are 2, 3, 4, 64, 70, 103, 104, 105, 106, I10, I13, I17, 120, 125,
138, 140, 141. From the great number of stations it will be seen that this species not only without
comparison has been the Colossendeis most frequently found, but also that in this respect it is inferior
to no other Pycnogonid. It is especially in the southern part of the Norwegian Sea near the Farde
Islands, just at the boundary of the Atlantic that it has been found; it has, however, also been taken
farther north in the same seas towards Jan Mayen, and one single specimen has been taken some
way up in the Greenland Sea, stat. 125, 68°08’ Lat.N. 16°02’ Long.W. A few stations are also
found in the Atlantic south of Iceland, stat. 64, 62°06’ Lat. N. 19° 00’ Long. W. with a depth of
1041 fath. The depths were otherwise varying between 134 and 1309 fath., most frequently some
7—800 fath. |

Distribution. From the Kara Sea (Hansen) and N. W. of Beeren Eiland (Sars) it is
spread especially to the south in the Norwegian Sea and the Farée-Shetland Channel (Hoek), and
from there sparsely round the southern coast of Iceland to the eastern coast of North America
(Wilson).

<8

60 PYCNOGONIDA.

5. Colossendeis macerrima Wils.

Colossendeis macerrima Wilson, Report Pycnog. «Blake», 1881, p. 246.
PLI. Fig. 2. Pl. WI. Fig. q—12. Pl. V. Fig. 32.

Occurrence. The Ingolf-stations 1z and 88 are in the Denmark Strait, partly midway
between Greenland and Iceland, partly in the mouth of Bredebugt in the latter island. The depths
were 1300 and 76 fath. Only two specimens were taken of which one, from Bredebugt, was a little
young (without chelifori).

Distribution. The species had until then only been taken in one single specimen on
38° 18' 40" Lat. N. 73° 18' 10” Long. W. at a depth of 922 fath. (Wilson).

IV. Fam. Phoxichilide.

Corpus manifeste in segmenta partitum.

Rostrum cylindricum vel conicum, inflexibile, libratum vel nutans.
Chelifori vel robustiores, vel graciliores, vel deficientes.

Palpi deficientes.

Pedes oviferi in femina deficientes.

The trunk distinctly segmented.

The proboscis cylindrical or conical, inflexible, horizontal or directed obliquely downward.
The chelifori powerful, or slender, or wanting.

Palps wanting.

Ovigerous legs wanting in the female.

2. Subfam. Pycnogonini.

Chelifori deficientes.

Chelifori wanting.

Gen. Pyenogonum (Briinn. 1764).

Pycnogonum Wilson, Syn. Pycnog. New-Engl, 1878.

PYCNOGONIDA. 61

Pycnogonum crassirostre G. O. Sars.

Pycnogonum crassirostre Sars, Pycnog. bor. arct., 1888, p. 340.

— - Idem, Pycnogonidea, 1891, p. 12. Pl. I. Fig. 2, 2 a-h.

Occurrence. The Ingolf-Station 88 is in the Denmark Strait in the mouth of Bredebugt
in Iceland, at a depth of 76 fath., bottom temperature 6°9. One single male.

Distribution. Sars, Pycnogonidea, 1891, p.14, could for his three specimens give no nearer
determination than close to the coast of Norway, adding, however, from our museum a station in the
Denmark Strait, off Dyrafjord in Iceland (Ryder). I should be inclined to think that the species
keeps close to the coasts on not too deep water.

62 PYCNOGONIDA.

LIST OF LITERATURE.

Adlerz, G.: Bidrag till Pantopodernas Morfologi och Utvecklingshistoria.
Bih. t. K. Svenska Vet.-Akad. Handl. B. 13. Afd. IV. Nr. rz. Tafl. I—II. 1888.
Balfour, F.M.: Notes on the Development of the Araneina.
Quaterl. Journ. Microsc. Sc. New Ser. Vol. 20. p. 167—8g9. Pl. XIX—XXI._ 1880.
Bell, Th.: Account of the Crustacea.
Last of the arct. voy. und. the Comm. of Capt. Sir Edw. Belcher in search of Sir John Franklin
dur. the years 1852—53—54. II. 1855.
Briinniche, M.Th.: Entomologia sistens Insectorum Tabulas Systematicas cum Introductione et
Iconibus. Insektlere, indeholdende Insekternes systematiske Tavler samt Indledning og Fi- °
gurer. 1764.
Bohm, R.: Ueber die Pycnogoniden des K6nigl. Zoologischen Museums zu Berlin, insbesondere iiber
die von S. M.S. Gazelle mitgebrachten Arten.
Monatsber. k6n. preuss. Akad. d. Wiss. zu Berlin, aus d. Jahre 1879. p. 170—195. Taf. I—II. 1880.
Caullery, Maur.: Pycnogonides.
Résult. scient. d. 1. Campagne du «Caudan» dans le Golfe d. Gascogne.: Aoiit.-Sept. 1895. Fase. II.
p- 361—64. Pl. 12. 1806.
Cavanna, G.: Studi e ricerche sui Picnogonidi.
Publicaz. del r. istit. di super. prat. e di perfez. in Firenze. Sez. di scienze fis. e natur. p. 3—109. -
Tav.I—II. 1877.
Dohrn, A.: Untersuchungen iiber Bau und Entwicklung der Arthropoden.
Jenaische Zeitschr. f. Medic. u. Naturw. V. p.138—57. Tab. V—VI._ 1870.
— Die Pantopoden des Golfes von Neapel und der angrenzenden Meeres-Abschnitte.
Fauna u. Flora d. Golf. v. Neap. u. d. angr. Meer.-Absch. herausgeg. v. d. Zool. Stat. zu Neapel.
III. Monographie p. 1—252. Taf. I—XXII. 1781.
Fabricius, O.: Fauna Groenlandica. 1780.
Goodsir, H.: Description of some new species of Pycnogonidz.
Jamesons Edinb. Phil. Journ. XXXII. 1842.
— On the Specific and Generic Characters of the Araneiform Crustacea.
The Ann. and Mag. of Natur. Hist. Vol. XIV. p.1—4. PLI. 1844.
Grassi, B.: Intorno ad un nuovo Aracnide artrogastro (Koenenia mirabilis), che crediamo rappresen-
tante dun nuovo ordine (Microteliphonida). Estr. dal Natural. Sicil. Anno IV. p.1—14. 1885.
— I Progenitori dei Miriapodi e degli Insetti. Memorie V. Intorno ad un nuovo Aracnide artro-
gastro (Koenenia mirabilis) rappresentante di un nuovo ordine (Microtelyphonida).
Bull. Soc. Entom. Ital. Anno XVIII. p. 153—72. Tav. IX—X. 1886.
Hansen, H:J.: Fortegnelse over de hidtil i de danske Have fundne Pycnogonider eller Sospindler.
Naturh. Tidsskr. 3. R. 14. B. p.647—52. 1884.

PYCNOGONIDA. 6 3,

Hansen, H. J.: Zoologia Danica, Afbildninger af danske Dyr med populer Text. H.4. 1885.
— Kara-Havets Pycnogonider. ;
Dijmphna-Togtets zoologisk-botaniske Udbytte. p. 3—27. (157—81). Tab. XVHI—XIX. 1886.

Hansen, H.J.og Sorensen, Will: The Order Palpigradi Thor. (Koenenia mirabilis Grassi) and
its Relationship to the other Arachnida.
Entom. Tidskr. Arg. 18. H. 3—4. p. 223—40. Tafl. IV. 1897. 1898.

Heller, Cam.: Die Crustaceen, Pycnogoniden und Tunicaten des K. K. Oester. Ungar. Nordpol-
Expedition 1875.
Denkschr. d. kais. Akad. d. Wiss. in Wien. Math.-naturw. Cl. Bd. 35. 1878.
Hoek, P.P.C.: Ueber Pycnogoniden.
Niederl. Arch. f. Zool. 3. Bd. p. 1—20. Taf. XV—XVI. Separate Copy. 1877.
— The Pycnogonids, dredged during the Cruises of the «Willem Barents» in the years 1878 and 1879.
Niederl. Arch. f. Zool. Supplementb. 1. p. 1—18 (Separate Copy). Pl. I—II. 1881.
— Report on the Pycnogonida.
The Zool. of the Voy. of H. M.S. Challenger. Part. X. 1881.
— Nouvelles études sur les Pycnogonides.
Arch. d. Zool. expér. et génér. Vol. IX. p. 445—542. Pl XVIJI—XXX. 1881.

Thle, J.E.W.: Ueber die Phylogenie und systematische Stellung der Pantopoden.
Biolog. Centralbl. XVIII. B. Nr. 16. 1898.

Jarzynsky, Th.: Praemissus catalogus Pycnogonidarum inventarum in mari glaciali ad oras Lap-
ponize rossicee et in mari albo, anno 1869 et 70.
Ann, d.l. soc. d. Natur. d. St. Pétersbourg. 1870.

Kingsley, J:S.: The Classification of the Arthropods.
Amer. Natural. XXVIII. Febr. p. 118—35 and 220—35. 1894.

Fa, Sek

Korschelt, E. und Heider, K.: Lehrbuch der vergleichenden Entwicklungsgeschichte der wirbel-
losen Thiere. Specieller Theil. Erstes Heft. 1890.:

Kroyer, H.: Gronlands Amfipoder beskrevne. (Som Tilleeg: Beskrivelse af nogle andre gronlandske
Kreebsdyr, og Opteelling af Kreebsdyrklassens hidtil bekjendte gronlandske Arter, i Forbindelse
med nogle zoologisk-geografiske Bemzerkninger over de boreale Krustaceer).

K. D. Vid. Selsk. Nat. Math. Afhandl. VII. p. 229—326. Tab. I—IV. 1838.
— Om Pycnogonidernes Forvandlinger.
Naturh. Tidsskr. 1. R. 3. B. p. 299—306. PL III. 1840.
— Bidrag til Kundskab om Pycnogoniderne eller Sospindlerne.
Naturh. Tidsskr. 2. R. 1. B. p.9go—139. PLI. 1844.
— Gaimard, Voyages en Scandinavie, en Lapponie etc. Zoologie. Crustacées.
Pl. 35—39. 1849.

Latreille, P.A.: Cuvier, Le régne animal, éd. II. Tome IV. 1829.

Locy, Wm.: Observations on the Development of Agelena neevia.

Bull. Mus. Comp. Zo6l. Harv. Coll. Cambridge. Vol. XII. p.63—103. Pl.I—XII. 1885.

Meinert, Fr.: Fluernes Munddele. Trophi Dipterorum. 1881.
Miers, Edw.: On a small Collection of Crustacea and Pycnogonida from Franz-Joseph Land, collected
by B. Leigh Smith, Esq.
The Ann.and Mag. of Natur. Hist. Ser. 5. Vol. VIL. p.45—51. PI. VII. 1881.

64 PYCNOGONIDA.

Morgan, T.H.: A Contribution to the Embryology and Phylogeny of the Pycnogonids.
Stud. from the Biolog. Laborat. Baltimore. Vol. V. Nr. I. p.1—76. PLI—VIIL. 1891.
Sabine: Marine invertebrate animals.
A Suppl. to the Append. of Capt. Parry's Voyage in the years 1819—20. 1824.

Sars, G.O.: Prodromus descriptionis Crustaceorum et Pycnogonidarum, que in Expeditione Norve-
gica anno 1876 observavit.

Arch. f. Math. og Naturv. II. p. 337—271 (371). 1877.
Crustacea et Pycnogonida nova in itinere 2do et 3tio expeditionis Norvegicee anno 1877 & 78
collecta. (Prodromus descriptionis).
Arch. f. Math. og Naturv. IV. p. 427—76. 1880.
— Pycnogonidea borealia & arctica enumerat (Prodromus descriptionis).
Arch. f. Math. og Naturv. XII. p.339—56. 1888.
— Pycnogonidea.
' Den norske Nordhavs-Expedition 1876—78. XX. Zoologi. Pl. I—XV._ 1891.
Schimkéwitsch, W.: Sur les Pantopodes recueillis par M. le lieuteuant G. Chierchia pendant le
voyage de la corvette «Vettor Pisani» en 1882—1885.

Reale accad. dei Lincei (Anno CCLXXXVI 1889). Ser. 4. Mem. d. Cl. di se. fis. mat. e nat.
Vol. VI. 1890.

— Compte-rendu sur les Pantopodes.
Rep. dredg. oper. of the West-Coast of Central-Amerika to the Galapagos ete. Bull. Mus. Comp.
Zool. Harv. Coll. Vol. XXV. Nr. 2. p.27—48. Pl. I—II. 1893.
Semper, C.: Ueber Pycnogoniden und ihre in Hydroiden schmarotzenden, Larvenformen.
Arbeiten aus d. Zool. Zoot. Instit.in Wiirzburg. I. p. 264—86. Taf. 16—17. 1874.
Wilson, Edm.: A Synopsis of the Pycnogonida of New England.
Trans. Conn. Acad. of Arts and Seiences. V. Aug. 1878. p.1—26. PLI—VII._ 1878.
— The Pycnogonida of New England and Adjacent Waters.
Rep. Unit. Stat. Commiss. of Fish and Fisheries. Part. VI. for 1878, p. 463—506. PlI—VII. 1878.
— Report on the Pycnogonida («Blake»).

Rep. Results Dredg. Superv. A. Agassiz, along the East Coast of Unit. Stat. etc. Bull. Mus.
Comp. Zo6l. Harv. Coll. Vol. VIII. Nr. 12. p. 239—56. Pl. I—V. 1881.

Zenker: Untersuchungen itiber die Pycnogoniden.
Arch. f. Anat. u. Phys. u. wiss. Medic. Jahrg. 1852. p.379—91. Taf. X. 1852.

PYCNOGONIDA. : 65

Bigy 5:

Fig. 7:

Fig. Io:

EXPLANATION OF THE PLATES.

Tab. I.

Fig. 1—4. Pycnogonum littorale Strom.

: First beginning of the embryo, from below.

The proboscis and the three pairs of embryonal limbs are seen as low tubercles.

: The embryo, somewhat more advanced, from below.

The embryonal legs are seen as long appendages, all resembling each other, with the only

exception that the foremost pair show at the point an indistinct cleaving as the beginning
of the fingers of the chela or hand.

: Larva of the first stage, from below.
: Larva of the third stage, dorsal view.

The embryonal limbs have all been thrown off, but the eyes are distinctly seen on the fore-
most, somewhat constricted part of the first segment of the trunk, and the three foremost
pairs of the ambulatory legs have all their complete number of joints.

Fig. 5—6, Phowichilidium femoratum Rathke.

Larva of the first stage, from below.
The proboscis is not distinctly marked off, but seems to be a continuation of the trunk;
byssus-threads wanting.

: The same, dorsal view.

The outermost joints of the embryonal limbs have been cut off.

Fig. 7—9. Pseudopallene spinipes Fabr.

Larva of the second stage inside the egg, lateral view.
Very early stage of development. No trace of embryonal legs.
a. Chelifori; 4. foremost pair of ambulatory legs.

: The same stage, lateral view.

Somewhat more advanced; in this specimen the rudimentary embryonal legs are seen.
a. First pair of embryonal legs; 4. second pair of embryonal legs.

: Free larva of the second stage, lateral view.

Here (only in this specimen?) no trace of embryonal legs are seen. The byssus-threads are
now found.

Fig. 1o—15. Pseudopallene circularis Goods.

Free larva of the second stage, lateral view.
a. First pair of embryonal legs; 4. second pair of embryonal legs; c. the byssus-gland.

The Ingolf-Expedition. II. 1. 9

PYCNOGONIDA.

Fig.

Fig.

Fig.

¥7

19:

20:

aI:

22:

23:

24:

25:

26:

: The same, from below.

a. The common ganglionic mass.

: Larva of the second stage, from below.

Here and in the following three figures only a small part of the ambulatory legs has been given.

: The same, dorsal view.
: Larva of the second stage, from below.
: A young one, from below.

a.a. Newly begun ovigerous legs.

Fig. 16—17. Pallene brevirostris Johnst.

: Free larva of the first stage, lateral view.

a. First pair of embryonal legs; 4. second pair of embryonal legs; c. byssus-threads.

: The same, somewhat reduced, dorsal view.
‘a.a. The byssus-threads from both the chelifori.

Fig. 18—19. Pallene hastata n. sp.

: Free larva of the second stage, lateral view.

No trace of embryonal legs are seen here, such as in Pall. brevirostris, but the development
is here somewhat more advanced, which may perhaps account for the difference. .

a. The proboscis.

Free larva of the second stage, lateral view.

The larval stage is here more advanced, near its close.

a. The proboscis.

Fig. 20—29. Nymphon grossipes Fabr.

Larva of the second stage, lateral view.

The ambulatory legs begin to appear, and a byssus-thread is secreted.

Larva of the second stage, lateral view.

The stage considerably more advanced.

The fore part of the same, more enlarged.

a. Byssus-gland.

Larva of the second stage, dorsal view.

The two foremost pairs of ambulatory legs are fully articulated with well developed claws
and auxiliary claws, the second pair only want one joint.

a.a. The byssus-glands.

The same, from below.

The greater part of the two foremost pairs of ambulatory legs has been cut away. The
yolk-mass is seen to continue from the trunk into the ambulatory legs, bordered by the
future wall of the stomach.

a.a. The byssus-glands; 4. 4. first pair of embryonal legs; c.c. second pair of embryonal legs.
The fore part of the same, more enlarged.

a. The first embryonal leg; 4 the second embryonal leg; ¢. the proboscis.

Larva of the third stage, dorsal view.

The development of the fourth pair of ambulatory legs is already pretty well advanced.

PYCNOGONIDA. 67

Fig. 27:

— 28:
— 20:

Fig. 1:

The same, from below.

The embryonal legs have now been thrown off, and the development of the imaginal fore
limbs has begun.

a.a. The palps; 4.4. the ovigerous legs.

A palp (third larval stage) newly begun.

An ovigerous leg (third larval stage) newly begun.

‘bap; 16.

Fig. 1—7. Nymphon robustum Bell.

First beginning of the embryo, lateral view.
The embryonal legs are seen as distinct swellings.

: Larva of the second stage, lateral view.

The larva is still enclosed in its membranes (and egg-shell?), but the trunk is already seg-
mented, and the foremost pair of ambulatory legs are pretty long.
a. The chelifori; 4. the first embryonal leg enclosed by a dermal sheath; c. the second em-
bryonal leg; d. the proboscis; ¢. the first pair of ambulatory legs.

: The proboscis, somewhat more enlarged, lateral view.

Four cast-off sloughs of the proboscis are seen to be lying one within the other, with the
corresponding walls of the intestinal canal arranged in the same way.

Larva of the second stage, lateral view.

This phase is older than that of fig.2 it having got the byssus-threads; the second pair of
ambulatory legs are also long, and the first pair distinctly articulated; on the other hand
only the two foremost segments of the trunk have been constricted, and the two hindmost
pairs of ambulatory legs scarcely begun.

f. The second ambulatory leg. The other letters as in fig. 2.

: Free larva of the second stage, lateral view.

A still older phase than fig. 4; nevertheless the last pair of ambulatory legs have not yet
been fully developed, but the larva is free of the egg-shell and the membranes.

: The same, from below.

The letters as in the preceding figures.

: Larva of the third stage, dorsal view.

The embryonal legs and the byssus-threads are thrown off, but the newly begun imaginal
fore limbs have appeared. Of the ambulatory legs only one leg of the foremost pair has
been kept.

a.a. The chelifori; 4.4. the palps; c.c. the beginning of the ovigerous legs.

Fig. 8—12. Nymphon macronyx G. O. Sars.

Fig. 8: Larva of the first stage, dorsal view.

The embryonal legs and the proboscis are hidden by the trunk.
a.a. The chelifori; a.’ a’. the ducts of the byssus-glands.

: The same, from below.

a.a. The chelifori; @’.a’. the ducts of the byssus-glands; 4. 4. the first pair of embryonal legs;
c.c. the second pair of embryonal legs; @. the proboscis; ¢. common ganglionic mass for the
embryonal legs.

9*

68

PYCNOGONIDA.

Fig. 13:

Fig. 15:

Fig. 17:

Fig. 19:

: The same, lateral view.

a. The cheliforus; a’. duct of the byssus-gland; 4. the first embryonal leg; c. the second em-
bryonal leg; @. the proboscis; ¢. the byssus-gland.

: Larva of the second stage, lateral view.

J. The three foremost ambulatory legs. The other letters as in the preceding figure.

: Larva of the second stage, lateral view.

An older phase than fig. rr.
a. Cheliforus; 4. the first embryonal leg; c. the second embryonal leg; d@. the proboscis; ¢. the
first ambulatory leg; £ the second ambulatory leg.

Fig. 13—14. Nymphon spinosum Goods.

Larva of the second stage, lateral view.

The larva is in a very early phase of the second stage, still lying in the egg-shell, and
with the foremost pair of ambulatory legs only short and still unjointed.

a. Cheliforus; a’. duct of the byssus-gland; 4. the first embryonal leg; c. the second embryonal
leg; d. the first ambulatory leg; ¢. byssus-gland; £ egg-shell.

: Larva of the third stage, from below.

The embryonal legs and the byssus-threads have fallen off, but the articulation of the ima-
ginal fore limbs has begun. Of the fully developed ambulatory legs only one leg of the
second pair is kept.

a.a. The chelifori; 4.4. the palps; c.c. the ovigerous legs.

Fig. 15—16. Nymphon elegans Hans.

Free larva of the first stage, lateral view.
The beginning of the second stage is marked by the appearance of the byssus-threads.
The letters as in fig. 13.

: Larva of the second stage, lateral view.

a. Cheliforus; a’. duct of the byssus-gland; 4. the first embryonal leg; c. the second embryonal
leg; d. the proboscis; ¢. the first ambulatory leg; £ the second and third ambulatory leg;
g. byssus-gland.

Fig. 17—18. Nymphon Sluiteri Hoek.
Larva of the second stage, lateral view.

a. Cheliforus; 4. the first embryonal leg; c. the second embryonal leg; @. the proboscis; ¢. the
first ambulatory leg; “the second ambulatory leg; g. beginning of the third ambulatory leg.

: The same, from below.

Of the ambulatory legs only the basal end is kept.

a.a. The chelifori; 4.4. the first pair of embryonal legs; c.¢. the second pair of embryonal
legs; d. the proboscis; ¢. the ganglionic mass for the embryonal legs; f the ganglion of the
first segment of trunk; g. the whole ganglionic mass for the rest of the trunk.

Fig. 19g—21. Nymphon longitarse Kr.

Larva of the first stage, dorsal view.
a.a. The chelifori; a@’.a’. the ducts of the byssus-glands; 4. 4. the first pair of embryonal legs;
c.c. the second pair of embryonal legs; dd. the byssus-glands. ;

PYCNOGONIDA. 69

Fig. 20:

— 23:

— 24:

Fig. 25:

— 26:

— 27:

|
Pei ee

The same, from below.
d. The proboscis; ¢. ganglionic mass for the embryonal legs. The other letters as in the
preceding figure.

: The same, lateral view.

The letters as in fig. 19.

Fig. 22—24. Paranymphon spinipes Caull.')

: Larva of the first stage, dorsal view.

The letters as in fig. 20.

The same, from below.

The letters as in fig. 20.

The same, lateral view.

By a pressure of the covering glass the yolk-mass has been forced out into the first joint
of the right cheliforus, and has distended this joint; the claws of the embryonal legs have
also been curved by the same pressure.

Fig. 25—27. Zetes hispidus Kr.

Larva of the first stage, in the egg-shell, lateral view.

a. Cheliforus; 4. the first embryonal leg; c. the second embryonal leg; d@. the proboscis; e.
egg-shell.

Fore end of the same, more enlarged, lateral view.

a. Cheliforus; a’. duct of the byssus-gland; 4. first embryonal leg; c. second embryonal leg;
d. proboscis; e. egg-shell.

Larva of the first stage, dorsal view.

The letters as in the preceding figure.

Tab. II.
Fig. 1—6. Nymphon Sarsii n. sp.

: Full figure, dorsal view. 3 times enlarged.

The same, lateral view; all limbs removed. 6 times enlarged.
A cheliforus.

The outermost joints of the palps.

The outermost joints of the ovigerous legs.

The two joints of the foot with claw and auxiliary claws.

Fig. 7—13. Nymphon Hoekii n. sp.

: Full figure, dorsal view. 3 times enlarged.

: The same, lateral view; all limbs removed. 6 times enlarged.
: A cheliforus.

: The outermost joints of the palps.

: The outermost joints of the ovigerous legs.

: The claw of the ovigerous legs.

: The two joints of the foot with claw and auxiliary claws.

1) The specific name of sfznipes here in this plate is an error for spimosume.

PYCNOGONIDA.

70
Fig. 14—22. Nymphon Groenlandicum n.sp.

Fig. 14: Full figure, dorsal view. 3 times enlarged.

— 15: The same, lateral view; all limbs removed. 6 times enlarged.

— 16: Oculiferous tubercle, from behind.

— 17: A cheliforus.

— 18: The ends of the fingers of the chela.

— 19: The outermost joints of the palps.

— 20: An ovigerous leg. a. sensory (?).

— 21: A dermal leaf from the terminal part of the ovigerous leg.

— 22: The two joints of the foot with claw and auxiliary claws.

Fig. 23—24. Nymphon robustum Bell.
Fig. 23: The distal end of the fourth joint of the ovigerous legs.
— 24: The proximal end of the fifth joint of the ovigerous legs.
Tab. IV.
Fig. 1—7. Pallenopsis plumipes un. sp.
Fig. 1: Full figure, dorsal view. Natural size.
a.a. The rudimentary palps.
— 2: The same, lateral view; all limbs removed. Natural size.
a. Palp.

— 3: Fore end of the first segment of trunk with oculiferous tubercle and part of the chelifori.
Below the oculiferous tubercle with the two. foremost eyes the metamere of the chelifori is
seen; the first joints of the chelifori are truncate.

— 4: Outermost joint of the chelifori.

— 5: An ovigerous leg.

— 6: The outermost joint of an ovigerous leg.

— 7: The outermost joints of an ambulatory leg.

Fig. 8—13. Pallene acus n. sp.

Fig. 8: Full figure, dorsal view. 5 times enlarged.

— g: The same, lateral view; all limbs removed. 10 times enlarged.

— 10: The chela of a cheliforus.

— 11: The outermost joints of an ovigerous leg.

— 12: Three dermal leaves of the terminal part of an ovigerous leg.

— 13: The outermost joints of an ambulatory leg, with the edge on the last joint.

Fig. 14—19. Pallene hastata n. sp. ~’

Fig. 14: Full figure, dorsal view. 6 times enlarged.

— 15: The same, lateral view; all limbs removed. 12 times enlarged.

— 16: The chela of a cheliforus.

— 17: An ovigerous leg, with distinct sensory (?).

a. Sensory (?).
— 18: The outermost joints of an ambulatory leg, with the edge on the last joint.

: Part of the same edge, with a couple of the thorns of the leg. Much enlarged.

PYCNOGONIDA.

71

Fig. 1:

|
ee a ee

Fig. 20—28. Paranymphon spinosam Caull.
: Full figure, dorsal view. 6 times enlarged.

: The same, lateral view; all limbs removed. 12 times enlarged.
: A cheliforus with the chela bent backward.

: The movable finger of the chela.

: The outermost joints of a palp.

: An ovigerous leg

: The outermost joints of an ovigerous leg.

: An ambulatory leg.

: The outermost joints of an ambulatory leg. More enlarged.

Tab. V.
Fig. 1—6. Pallenopsis fluminensis Kr.

Full figure, dorsal view. 3 times enlarged.

On account of the position of the animal the gland ducts on the ambulatory legs are not

seen in this figure.

: The same, lateral view; all limbs removed. 6 times enlarged.

A cheliforus.
An ovigerous leg.

Part of the fourth joint of the first pair of ambulatory legs of the male, with gland duct.
The outermost joints of an ambulatory leg with claws and auxiliary claws.

Fig. 7—18. Ascorhynchus tridens n. sp.

Full figure, lateral view; all limbs removed. 6 times enlarged.

: The same, lateral view; all limbs removed. 8 times enlarged.

Oculiferous tubercle, from behind.
The outermost joints of a cheliforus (in a full-grown animal).

: A cheliforus of a very young animal.

: A cheliforus of a somewhat older animal.

: A cheliforus of a full-grown animal (abnormal).
: A palp with distinct sensory (?).

a. Sensory (?).

: An ovigerous leg.

: A dermal leaf from the terminal part of the ovigerous leg.
: The outermost joints of an ambulatory leg, in the male.

: The outermost joints of an ambulatory leg, in the female.

Fig. 19—20. Colossendeis clavata n. sp.

: Full figure, dorsal view. Two thirds of the natural size.
: The same, lateral view; all limbs removed. Twice the natural size.

Fig. 21—22. Colossendeis angusta G. O. Sars.

: A cheliforus of a very young animal.
: The outermost joints of a palp of a very young animal.

Stereo |

ERD ees
c ope et
> Rien

Tr. Meinert: Pyenogonida’ Tab. I.

Lngoll Kapedition MIL.

Lseudopallene spinipes: 7-9.

Fall. hastata: 181g.

LPhoxtchilidium ftemoratum: 5 " C6.

Lallene brevirestris: 16

‘Ly cnogonun littorale: i-
Preudopall. ctreularis: 10
Meinert del. Ses

Nymphow grossipes: 20-29.

—f7.

4.

25.

Sen

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ares.

Ingolf Kwepedition Il.

B 4:

Nymphon robustum: 1-7. Nymph: macronyo: 8-12.
Nymph. Slutteri: 17-18. Nymph: longttarse: 19-21.

Meinert del.

Nymph. spinosune: 13 14.
Laranymphorw sptripes: 22-24.

Ft. Meinert: Pyenogonida’ Tab. IT.

Nymph. elegans: 15-16.
Retes hispidus: 25-27.

Lévendal se.

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tr. Meinert: Lycnogonida Tb. HI.

ee ee SITET

Nymphorw Sarsti: 1-6. Nymph. Hochkii: 7-13. Nymph: CGroentandicum: 14-22.
Nymph: robustum: 23-24.

a |

Bloch « Meinert del. Lévendal se.

cl
PENG ce
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Fr. Meinert: Lycnogonida’ Tab. IV.

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28.

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Pallenopsis plumipes: 1-7. Fallene acus: 8-13. Fatllene hastata: 14-19.

Paranymphor sptnosum: 20-28.
* Bloch « Meinert det.

Lévendal se.

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Fr. Meinert: Pycnogonida’ Tab. V.

Ingolf Rapedition Il.

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Colossendeis claoata: 19-20.

£8.

Ascorhynchus tridens: 7

fallenopsis tluminensis Hr: 1-6.

DLévendal se.

Coloss. angusta jun: 21-22.

Bloch «Meinert del.

UNIVERSITY
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THE INGOLF-EXPEDITION

1895—1896,

THE LOCALITIES, DEPTHS, AND BOTTOMTEMPERATURES OF THE STATIONS.

Depth Depth Depth
yt "| Eat N. | Long. W. ao pean : sa "| Lat N. |Long. w. — pene — agente sT Sealine crt pong
fathoms fathoms fathoms
I 62° 30° 8° 21’ 132 yea oe 63° 06° | 56°00’ 1199 2°4 45 61° 32° 9° 43° 643 4°17
2 63° 04’ 9° 22’ 262 5°3 25 63° 30° | 54° 25’ 582 3°3 46 61° 32° | 11° 36’ 720 2°40
3 63° 35° | 10° 24’ 272 0°5 63° 51’ | 53° 03° 136 47 61° 32’ | 13° 40° 950 3°23
4 64° 07’ §7°.x2" 237 2°5 26 63° 57° | 52°41’ 34 0° 48 61° 32’ | 5° 11’ 1150 3°17
5 64° 40’ | 12°09’ 155 64° 37° | 54° 24’ 109 49 62°07’ | 15°07’ 1120 2°91
6 63° 43° | 14°34 go 7°0 27 64° 54 | 55° 10 393 3°8 50 62° 43 15° 07’ 1020 g713
7 63° 13° | 15°41 600 4°5 28 65° 14 | 55° 42° 420 | 305 51 64° 15° | 14° 22" 68 7°32
8 63° 56’ | 24° 40’ 136 6°0 29 65° 34’ | 54°31" 68 0°2 52 632 57.| ag% ar 420 7°87
9 64° 18’ | 27° 00 295 5°8 30 | 66°50° | 54° 28" 22 | 1°05 53. | 63° 15° | 15°07 795 3°08
10 64° 24" | 28° 50" 788 | 3°5 3r 66° 35° | 55°54’ 88 | 1% 54 | 63°08" | 15°40 691 3°9
Ir 64° 34’ | 31°12" | 1300 | 16 32 66° 35° | 56° 38" 318 | 3°9 55 63° 33° | 15°02" 316 5°9
12 64° 38’ | 32°37 | 1040 | 0°3 33 67° 57° | 55° 30 35 | 0° 56 | 64° 00° | 15° 09" 68 7°57
13 64° 47 | 34°33 622 3°0 34 65°17 | 54°17 55 57 63° 37° | 13°02" 350 3°4
14 64° 45° | 35°05 176 4°4 35 65° 16° | 55°05 362 | 3°6 58 64° 25° | 12° 09' 211 0°8
15 66° 18’ | 25° 59° 330 | —0°75. 36 61°50 | 56° 21’ 1435 ws 59 65° 00° 11° 16’ 310 | —o°r
16 65° 43° | 26° 58’ 250 6°r 37 60° 17° | 54° 05° 1715 1°4 60 65° 09! ta° 27" 124 0°9
17 62° 49° | 26° 55° 745 | 3°4 38 59° 12’ | §1°05' | 1870 1°3 61 65° 03' | 13° 06 55 0°4
18 61° 44’ | 30° 29° 1135 3°0 39 62° 00’ | 22° 38’ 865 2°9 62 63° 18’ | 19° 12’ 72 7°92
19 60° 29’ | 34°14 1566 2°4 40 62° 00° | 21° 36’ 845 kek 63 62° 40° | 19° 05’ 800 4°o
20 58° 20° | 40° 48’ 1695 1°5 41 61° 39° 17° 10 1245 2°0 64 62° 06’ 19° 00’ 1041 373
21 . 58° or | 44° 45 1330 2°4 42 61° 41’ 10° 17’ 625 0°4 65 61° 33° | 19° 00° 1089 3°0
22 58° 10° | 48° 25’ 1845 1°4 43 61° 42° 1o° rr’ 645 0°05 66 61° 33° 20° 43" 1128 3°3
23 60° 43° | 56° 00° Pinkin Ne 44 61° 42’ 9° 36 545 4°8 67 61° 30° | 22° 30’ 975 3°0

Depth Depth Depth
Sion rong W| Tat | [tam Son tat rong w|, |Pomam| Sion] tats, [tong etm
fathoms fathoms fathoms
68 62° 06’ 22°40: 843 3°4 92 64° 44’ 32° 57 976 1°4 118 68° 27’ 8° 20° 1060 | —1°o
69 62° 40° *s 17 } > 589 9 A 93 : 64° h , 35°74, 77 . p46 =! ae 67° 53, 10° 19° as IoIo | —1°o
70 | 63° og" || he og | 134 | 7° ] } 94° | 44°56 | 36% 9) | 204 |/ gory |i tho! | 67°26! 19 37°)| 885. | —1°0
71 63° 46° 22° 03" 46 65° 31’ | 30°45 213, 121 66° 59° | 13° 11’ 529 | —0°7
72 | 63°12" | 23°04" 197 6°7 95 65° 14 30° 39° Y 752 2°r 122 66° 42’ | 14° 44’ 115 198
73 62° 58 =| 23° 28 486 5°5 96 65° 24° | 29° 00 735 2°2 123 66° 52” 15°40 145 2°0
74 | 62°17 |.26° 36 fr 6956} 24°92 © 2197 A 45659284 27% 39) 4504 | > 5°S ifs d2g- =) O72 Ao, MS? Aor | 495 | —0°6
61° 57’ a5? 25! 761 98 65° 38° 26° 27’ 138 5°9 125 68° 08’ 16° 02’ 729 | —o°8
61° 28’ | 25° 06’ 829 99 66° 13’ | 25°53" 187 6°r 126 67° 19 | 15° 52° 293. | —o%§
75 61,°'28’ | | 26° 25° . 780 4°3 100 66° 23° 14° 02’ 59 0°4 127 66° 33 |. 20° 05° 44 1 596r
i 76 60° 50 | | 26° 50° 806 4°1 IOI 66° oat) 12°95" 537 —0%7 128 66° 50’ | 20° 02’ ra 0%
77 60° 10° | 26° 50’ 951 3°6 102 66° 23° | 10° 26’ 750 | —0°%9 129 66° 35° | 23° 47’ 117 6°5
78 60° 37’ | 27° 52’ 799 aes 103 66° 23’ |» 8% 52’ 579 | —0°6 130 63° 00’ | 20° 40" 338 6°55
79 60°52’ | 28° 58’ 653 4°4 104 66° 23° | 207° 25° 957. | —191 131 63° 00’ | 19° 09’ 698 4°7
80 | 61° 02" | 29° 32’ 935 4°o 105 | Gs? 34. ey gr" 762 | —o°8 132 | 63°00 | 1704 | 747 4°6
#183 61° 44’ | 27° 00" 485 6°r 106 65° 34° 8°54" ‘447 | —0°6 133 63% 14" | ‘rr? 24’ 230 p°2
» 82 61°55 | 27° 28’ 824 4° 65° 29° | 8° 40’ 466 134 62° 34’ | .10° 26’ "299 a°r
83 62°25" | 28° 30’ gi2 3°5 107 65° 33° | 10°28’ 492 | —0°3 135 62° 48’ | | 9°48’ 270 0°4
62° 36’ |'26° o1' 472 108 65° 30° | 12°00 97 Or 136 63° o1' 9° ar’ 256 4°8
62°36’ | 25° 30° 401 109 65° 29 | 13°25 38 1°5 137 63° 14 8°'31’ : 297 —o°6
84 62°58’ | 25° 24’ 633 4°8 110 66° 44’ | 11° 33" *98r | —o°8 138 63° 26 | + 7°56 | °' 471 | —0%
85 63°21 | | 25° a1’ 170 III 67° 14’ | 8°48’ 860 | —o°9 139 63° 36 7°30' | } 702 | —o0%6
86 | 65°.03'6 | 23° 47'6 76 112 67° 57’ 6% 44’ | $4267 | —T°r 140. | 63°20" 6° 57 "780 | —0%9
87 65° 02'3 | 23° 562 110 113 69° 31’ | 7°06’ | 14309 | —t1°0 141 63° 22 6° 58 679 | —0°%6
88 64°58 | 24° 25’ 76 6°9 114 70° 36° | 7°29" 773 | —1°0 142 63° 07’ 7° 05 ' 587 | —0%6
89 64° 45’ | 27° 20° 310 8°4 TI5 70° 50° 8° 20’ 86 o°r 143 62° 58’ 7° 09 388 | —0%4
go 64° 45° | 29° 06° 568 4°4 116 70° 05’ | ‘8° 26’ a7r | —oo4 144 62° 49 7 ata! 276 1°6
gi 64° 44’ | 31° 00° 1236 g8x 117 69° 13° 8° 23 1003 | —1°o

NAVHNIGOTH WGVLF HLT $LOOWVV 3 13XV

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