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VOL. XLV.—PART II,—(No. 18).

THE HYDROIDS OF THE SCOTTISH NATIONAL
ANTARCTIC EXPEDITION, |

BY

JAMES RITCHIE, M.A., B.Sc.

[Wir Tree Puarss. |

EDINBURGH:

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ZgANTHSON Ax
“(( OCT 12 1958
SS LIBRARY

XVIII.—The Hydroids of the Scottish National Antarctic Expedition. By James
Ritchie, M.A., B.Sc., Fullerton Scholar, University of Aberdeen. Communicated
by W. 8. Bruce, F.R.S.E. (With Three Plates.)

(MS, received May 1, 1906. Read June 21, 1906. Issued separately March 16, 1907.)

The collection of Hydroids hereafter described was made in the years 1902-4 by
the Scottish National Antarctic Expedition ship Scotia, during her cruises in Antarctic
and sub-Antaretic seas.

For the opportunity of examining the specimens I am indebted to Mr, W. 8. Brucu,
the energetic leader of the expedition ; and I also wish to thank Professor J. ARTHUR
THomson for much assistance and advice in the course of my work.

The collection, as here described, contains 41 specimens, of which 33 are referable
to 27 known species distributed among 15 genera, some of them being new varieties ;
while the remainder have required the establishment of 7 new species and 1 new
genus. Qne specimen remains specifically undetermined. Thus there are in all 18
different genera, represented by 35 different species.

Before dealing with the detailed systematic aspect of these forms, a few general
notes may be inserted :— ;

(1) The habitat of the forms shows considerable diversity. Sixteen of the speci-
mens were associated with Aleyonarians, being found along with, or growing upon,
those forwarded to Professor THomson for identification; eight occurred upon larger
Hydroids; while two were creeping upon seaweed fronds. Sponges formed the
foundation upon which several of the remaining colonies were erected.

(2) With the specimens were associated many types of life. Frequent
diatoms and foraminifera lay within the hydrothecee or upon the stems; various
sponges rested upon or surrounded some of the branches; and there were also
numerous climbing or encrusting polyzoa, a few cirripede galls, and occasional
pycnogonids.

(3) Of new forms described the most interesting is one of those rare types, apart
from the Plumularians, in which distinct nematophore structures have been found
(ALLMAN, 1883, p. 6; QuELCH, 1885, p. 4), and for it we have formed a new genus,
which we have named Brucella in honour of Mr Bruce. The beautiful, highly
specialised coppinia-gonosome of this type indicates close affinities with the family
Lafoéidee in which it has been placed.

TRANS. ROY. SOC. EDIN., VOL. XLV. PART II. (NO. 18). 73

520 MR JAMES RITCHIE

(4) Another new form, belonging to the genus Staurotheca, is also worthy of
mention as showing a development of the decussate arrangement of hydrothecse, which
necessitates a slight modification in the generic characters as originally described by
ALLMAN (1888, p. 75).

(5) The occurrence among the specimens of the coppinia-gonosome of Grammaria,
which has only within the last few months been described by Harriaus (1905,
p. 597), is of interest, since the peculiar structure of this gonosome aggregate
necessitates the transference of the genus from the neighbourhood of the Sertulariidee,
where it had been placed by ALLMAN in 1888, to close proximity with the far-removed
Lafoéidee.

(6) Throughout the genus Haleciwm, here represented by five species, the occurrence
of minute, translucent points round the rim of the hydrotheca has been noted (PI. II.
fig. 5). These points, whose use ALLMAN did not happen to observe, are small, dome-
shaped thickenings on the inside of the perisarc, placed in a ring just above the base
of the hydrotheca, and to these are attached short strands from a disc-like portion at
the base of the polyp, which is thus moored to the walls of its insignificant hydrotheca.
Such refringent puncta are not confined to the Haleciidee, for similar structures in the
same position—just above the floor of the hydrotheca—were observed in the hydro-
thecee of Obelia geniculata.

(7) The Scotza collection contributes also to our knowledge of the geographical
distribution of Hydroids. Thus to the already wide distribution, Arctic to Antarctic,
of such forms as Lafoéa gracilima (Spitsbergen, Norwegian coasts, British coasts,
Magellan Straits, ete.) or Obelia geniculata (Norwegian coasts, British coasts, French
coasts, Kerguelen, ete.), still another locality is added, while several new records have
been made of the occurrence of less common forms.

(8) As a remarkable case of associated distribution we may refer to Silicularia
hemspherica, a simple Campanularian form, which has been recorded from three
different localities, namely, Falkland Islands (ALLMAN, 1888), Navarin Island, Tierra
del Fuego (Harriaus, 1905), and Gough Island (Scotia), and in each case it was found
in close association with Obelia geniculata.

In classifying the specimens according to their geographical occurrence, the regions
mapped out by ORTMANN (1896) and made use of by Professor Harriaus (1904) have
been adopted. Taking these as our standard, we find that ten of our specimens fall into
the Antarctic Pelagic Region, all belonging to the Southern Subregion, while twenty-
nine, including all the new forms, have been found in the Antarctic Littoral Region.
The remaining two were obtained at St Helena.

Before dealing with the systematic aspect of the collection, I should like to
express my special indebtedness to Professor Harriaus’s ‘ Hydroiden der magal-
haensischen Region und chilenischen Kiiste” in the Zoologische Jahrbiicher (1905),
and to Professor Nurrine’s excellent monographs on the American Hydroids (1900
and 1904),

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 521

Arranging the Scotia specimens according to the localities in which they were
obtained, we get the following list :—

Antarctic PrLacic REaqion.

(a) Antarctic cireumpolar subregion.
Nil.

(6) Southern circumpolar subregion.

Burpwoop Bank, 54° 25’ 8., 57° 32’ W. 56fms. Ist December 1903.
* Hebella striata, Allm.
* Calycella syringa, Linn.
Lafoéa antarctica, Hart.

* 4, gracillima (Alder).
* Grammaria magellanica, Allm.
* Halecium beanii, Johns.
* Synthecium robustum, Nutt.
* Sertularella filiformis, var. reticulata, n. var.
uF 4 tenella, Alder.
a 5 tricuspidata, Alder.

Antarctic LirroraL REGION.
FaLKLaNnD IsLanps.
(a) Port Stanley. 8th January 1903.
* Campanularia ungulata, Hinks.
Fs tincta, Hinks.
Sertularella contorta, Kirch.
Plumularia magellanica, Hart.
(6) Cape Pembroke. January 1903 to January 1904.
Sertularella contorta, Kirch.
SoutH Orkney IsLanps.
(a) MacDougall Bay. November 1903.
Obelia longissima, Pall.
(6) Scotia Bay. 25th March and 6th December 1903.
Campanularia, sp.
Obelia longissima, Pall.
* Halecium interpolatum, n. sp.
* Staurotheca reticulata, n. sp.
* Sertularella rectitheca, n. sp.
Srarion 411, off Coat’s Land, 74° 1’S., 22° 0’ W. 12th March 1903.
FHebella striata, var. plana.
Haleeium robustum, Allm.
GoucH Istanp. 22nd April 1904.
Silicularia hemispherica, Allm.
Obelia geniculata, Linn.
* Brucella armata, nov. gen. et sp.
Haleciwm tenellwm, Hinks.
Sertularella gayt, Lamx.
CaprE Co.ony.
(a) Cape Town Docks. May 1904.
Plumularia echinulata, Lamk.
9p pinnata, Linn.

* Indicates a new record for the Geographical Region.

522, . MR JAMES RITCHIE

Cars CoLtony—cont.
(b) 8 miles N. of Dassen Island. 18th May 1904.
Sertularella filiformis, var, reticulata, n. var.
(c) Saldanha Bay. 21st May 1904.
* Podocoryne carnea, Sars.
* Halecium halecinum, Linn.
Thujaria pectinata, Allm.
Sertularella arborea, Kirch.
* Antennularia hartlault, n. sp.
* Antennopsis scotic, n. sp.
* Plumularia unilateralis, n. sp.
Aglaophenia dichotoma (Johus.).

Sv HeEena.

Halecium robustum, Allm.

ms tenellum, Hinks.

The systematic grouping of the species represented in the Scotia collection is
as follows :—

I. GYMNOBLASTEA.
Family PopocoryNnip&.

Podocoryne carnea, Sars, 1846.

I]. CALYPTOBLASTEA,
Family Hatecipa.

Halecium beanti, Johns., 1847. Halecium tenellwm, Hinks, 1861.
5 halecinum, Linn., 1758. eh interpolatum, n. sp.
sj robustum, Allm., 1888.

Family CaMPANULARIID&.

Campanularia angulata, Hinks, 1861. Silicularta hemispherica, Allm., 1888.
“ tincta, Hinks, 1861. Febella striata, Allm., 1888.
an sp. » striata, var. plana, n. var.
Obelia geniculata, Linn., 1758. Calycella syringa, Linn.

», longissima, Pall., 1766.

Family Larokipé.

Lafoéa antarctica, Hartlaub, 1905. Grammaria magellanica, Allm., 1888.
» gracillima (Alder, 1857). Brucella armata, n. gen. et sp.

Family SERTULARIIDA.

Sertularella arborea, Kirch., 1884. Sertularella tricuspidata (Alder, 1856).
a contorta, Kirch., 1884. 3 rectitheca, n. sp.
5 jiliformis, var. reticulata, n. var. Thujaria pectinata, Allm., 1888.
“ gayt, Lamx., 1821. Synthectum robustum, Nutt., 1904.

x tenella (Alder, 1857). Staurotheca reticulata, n. sp.

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 523

Family PLUMULARIID.

Aglaophenia dichotoma (Johns.). Plumularia unilateralis, n. sp.
Plumularia echinulata (Lamk., 1836). Antennularia hartlaubi, n. sp.
pA magellanica, Hart., 1905, Antennopsis scotiz, n. sp.

as pinnata, Linn.

I. GYMNOBLASTEA.
Family PopocoryNip&.
Podocoryne carnea, Sars, 1846.

Enerusting three Gasteropod shells from one locality there occur gymnoblastic
colonies which cannot be separated from the above species. The nutritive hydranths
bear from 8 to 15 tentacles, 12 being most common, while the gonophore-bearing
individuals possess only 5 or 6. All the hydranths are in a contracted state, some of
the larger measuring about 0°8 mm. in height. Short chitinous spines stud the
investing crust at irregular intervals.

The gonophores are borne in threes or fours beneath the tentacles. The medusoid
has & tentacles, 4 larger and 4 smaller.

Locality, etc-—On empty shells of Nassa crepidula from Saldanha Bay, Cape
Colony. Trawl. 19th May 1904.

Il. CALYPTOBLASTEA.
Family HaLeciip.
Haleciun beanir, Johnstone, 1847.

Two fragments occur, one 4, the other 7 cm. high. The characters of the
species are well shown in the specimens; the polysiphonic stems and branches which
distally become monosiphonic ; the pinnate arrangement of the branches; the extreme
delicacy of the ramuli, especially in the distal regions; the frequent tiers of hydrothecee
and the peculiar female slipper-shaped gonothecee, with their openings placed medianly
instead of at the extremity. In the present specimens, as in ALLMAN’s (1888), only
slipper-shaped gonothecee occur. We note, however, that while the hydrothecze are in
some cases set on a “‘ short basal offset from the distal end of each indernode ” (ALLMAN,
1888, p. 12), in the majority of cases the primary hydrotheca arises directly from and
lies almost against the distal end of the internode, as figured by Harriavus (1905, p. 606,
fig. B’, a and 6b). From within these primary basal hydrothece arise the tiers
which are so common in the species.

Locality, etc.—Fathoms, 56. Date, Ist December 1903. Burdwood Bank.

5924 MR JAMES RITCHIE

Halecium halecinum, Linn., 1758.

A thick clump of stout fascicled stems and branches from the entrance to Saldanha
Bay. The stems and branches are truncated at an almost uniform height, are of a dark
brown colour, and bear small, hydrotheca-bearing shoots of a pale brown, and evidently
of younger age. The general appearance suggests that some agency having damaged
the old-established branches, the colonies have made an effort to survive by sending out
many small, much-branched shoots from the older and unharmed portions of the stem.

The architecture is similar to that described by Hinks. The hydrothecee are
alternate, one towards the distal end of each internode. ‘They are generally sessile, as
described and figured by Bitiarp (1904, p. 161) for young branches, and frequently
they contain the base of a tier of one or two secondary cups. Rarely in place of such a
tier there arises a blind regenerative stolon, the true branches arising just below the
hydrothecee. Thus it comes about that a tier of hydrothecee frequently appears in the
angle between a branch and its offshoot. Small refringent points are present round the
edge of the hydrotheca as in the other species of the genus (vide p. 525).

Gonosome.—The gonangia, of which only male are present, occur in densely packed
rows. They agree with Hrnxs’s description and figure, being slenderly ovate and
narrowing proximally into a short stalk with about two rings.

Locality, ete.—Entrance to Saldanha Bay, Cape Colony, in 25 fathoms. Date,
21st May 1904.

Halecium robustum, Allman, 1888.

A fragment of a strongly fascicled, upright, much-branched colony 5 cm. in
height. The branches lie roughly in one plane and are often bent at sharp angles, the
older rising irregularly from the stem, while the younger are approximately alternate,
and arise from the side of the proximal segment of the hydrotheca. The internodes,
which are long, but whose length varies from 0°6 to 1°5 mm., are separated by
slanting nodes and bear at their distal ends alternate hydrothece 0°2 mm. in
diameter from margin to margin, adnate at one side to the internode, with an insignifi-
cant, non-everted limbus, and rarely with a tier of one or two secondary hydrothece.
The proximal ends of the internodes are marked by slight annulations. Around the
inside of the limbus are situated small, light-refracting prominences, to which, as in the
other members of the genus, are attached strands keeping in place a fleshy dise at the
base of the hydranth which cuts off the perisarcal cavity from the exterior. The
hydranths are large and have a great number of tentacles.

Gonosome.—Not present.

Localities, ete.—(a) Station 411, off Coat’s Land. Lat., 74° 1’S; long., 22° 0’ W.
Depth, 161 fathoms. Surface temperature, 28°°9. Date, 12th March 1904.
(b) St Helena.

The specimens differ from that figured by ALLMAN (1888) in that. the branches

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 525

frequently have at their bases at least one athecate internode connecting the stem
process with the hydrophore-bearing portions of the branch. The present specimens
are also frequently annulated, while AttMay’s figures indicate that the original was
smooth.

Halecium tenellum, Hinks, 1861. (PI. II. fig. 4.)

Several specimens of an extremely delicate and graceful hydroid colony, growing
in bunches on the exposed axis of an Alcyonarian, are referable to this species. As
Hryks's description appears to be rather vague, | give a detailed description of the
specimens. The colonies are short, generally about 15 mm. in length, with un-
fascicled stems and irregular branches, which arise from the distal ends of the inter-
nodes, and in some cases, at least, from the base of a hydrophore. The branches lie for
the most part in one plane.

The stem is thin, having near its base a diameter of a little over 0°1 mm., and,
like the branches, it is divided into long slender internodes whose length varies between
0-8 and 0:9 mm. The internodes are separated by slanting nodes, between which
the stem zigzags, and on each side of which are annular constrictions. The hydrothece,
which are alternate and lie in one plane, are borne on short processes at the distal
ends of the internodes. They are cylindrical, trumpet-shaped, with a large, beautifully
everted limbus, and are usually prolonged by several similar segments (from two to
five in number), at the bases of which, on a level with the margin of the next lower
limbus, arise well-marked annulations. The diameter of a limbus from margin to
margin is 0°15 mm.

The fleshy parts are in good condition, and the following points were observed :—
The hydranths are large and not wholly retractile, measuring, from mouth of hydrotheca
to summit of hypostome, when extended, 0°3 mm. Just above the neck there is
a well-defined bulge, and above this again a disc, from the margin of which arise the
tentacles, about sixteen in number, enclosing the conical hypostome. Across the in-
terior of the hydrotheca, at the level of the base of the everted limbus, stretches a
flattened fleshy disc supported by a perisarcal septum through which, by a small
aperture, the coenosare passes. The dise is moored in its place by numerous delicate
strands attached to the perisare at rather irregular intervals. At the points of attach-
ment there arise from the limbus small, dome-shaped prominences, which, refracting the
light, appear as minute, clear dots

the “refringent puncta” of the Challenger Report.
The prominences are rather irregularly arranged just above the level of the septum,
on which the coenosarcal disc lies, and vary in number from about sixteen to twenty on
each limbus.

Gonosome.—The gonangia are ovate, broad in the proximal region, obtusely pointed
in the distal. They are supported on short stalks which arise from the sides of the
hydrothecze, and always from the lowest segment in any hydrotheca-tier. They are
0:9 mm. in length by 0°45 mm. in maximum diameter.

926 MR JAMES RITCHIE

Localities, etc.—(a) Growing on the axis of an Aleyonarian (Thowarella), and dredged
off Gough Island, lat. 40° 20’ 8, long. 9° 56’ W., at a depth of 100 fathoms. Date,
22nd April 1904. (6) St Helena.

Halecium interpolatum, n. sp. (Pl. I. fig. 3; Pl. IT. fig. 3.)

A number of colonies, the largest about 4 cm. high, have been found in a shore-
pool. The colony is fascicled for the most part, but becomes monosiphonie distally. In
the older colonies the lower portion of the stem, which is less than 1 mm. in diameter,
is usually destitute of important branches, while the upper portion bears long flexuous
branches, often 15 mm. in length, which leave the stem at acute angles and in different
planes. This structure gives the colonies the appearance of a miniature tree. The
branches arise either singly from the basal segment of a hydrotheca or directly from
the hydrocaulus, in diverging pairs, one being at a slightly higher level than the other.

The stem and branches are divided into slender internodes of very different lengths,
varying from over 1 mm. to 0°4 mm., and marked at both ends by an annulation.
The hydrothecz are alternate, and are borne at the distal ends of the internodes, two
thecate internodes being almost invariably separated by one or more athecate inter-
nodes. Very frequently a short, annulated, hydrotheca-crowned branch arises from the
basal segment of a primary hydrotheca. The hydrothecze are usually simple, consisting
of a strongly annulated peduncle about 1 mm. long, surmounted by a well-everted
limbus measuring 0°2 mm. from margin to margin. Occasionally a second limbus
arises on a short stalk within the first. Around the limbus occurs the row of refringent
prominences found throughout the genus, and here, as in the other cases which have
been examined, they serve as attachment points for strands supporting a disc at the
base of the polyp.

(onosome.—Not present.

Locality, etc.—Off rocks in shore-pool. Temperature, 30°-32°. Scotia Bay, South
Orkneys. 6th December 1903.

One of the branches ended in peculiar, stolon-like outgrowths, as is shown in fig. 3,
Pl. I. The specimens, which have probably been cast by some storm into the shore-
pool in which they were found, are in poor condition, being almost wholly overgrown
by polyzoa. The specific name is intended to suggest the presence of the characteristic
athecate intermediate internodes.

Family CAMPANULARIID&.

Campanularria angulata, Hinks, 1861.

Several specimens about 1 em. high were found creeping on an alga. ‘The specimens
agree with Hinxs’s description :—slightly branched stems ringed above the origin of the
pedicels; strongly rmged pedicels, usually with nine rings, sometimes with only about

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 527

five, and tapering somewhat towards their distal ends; hydrothecse campanulate,
even-rimmed, usually on long pedicels. In the present specimens there are present
none of the tendril-like stolons mentioned by most writers, but this is not surprising,
since in most cases the distal end of the colony is awanting.

Gonosome.—Not present.

Locality, etc.—Port Stanley, Falkland Islands; 64 fathoms. 3rd February 1904.

Campanularia tincta, Hinks, 1861.

This species is represented from one locality, that from which Harriavus (1905) has
described his specimens. The Scotia specimens, while apparently belonging to this
species, show a considerable resemblance to C. cylindrica, Allm. (1876, p. 114), from
which they differ in their diminutive size and in the absence of ringing at the base of
the peduncle. The present specimens, which are from 1°5 to 2 mm. high, have a
corrugated peduncle averaging some 0°9 mm. in height and surmounted by a ball-like
segment which bears the hydrotheca. The hydrothece are about 0'7 mm. long by 0°3
mm. in diameter, almost cylindrical, and narrow sharply at the base. The margin is
divided into twelve blunt teeth and is frequently marked by a regeneration line. The
gonosome is awanting.

Locality, etc.—Creeping on weathered hydroid stems, Port Stanley, Falkland
Islands. 3rd February 1904.

Campanularia, sp. (PI. I. fig. 2.)

Lack of material forbids the assigning of a specific name to this form. Delicate
simple stems about 3 mm. high and 0°05 mm. in diameter arise at irregular
intervals from a creeping tubular stolon. ‘The hydrothecee are deep, campanulate, 0°8
mm. in length by 0°5 mm. in greatest diameter, with their cavity cut off from that of the
stem by a distinct partition. Their margin is divided into twelve or fourteen teeth, a
delicate line sometimes following the curves of the teeth just within the edge. The
hydrothecz, which are marked by delicate, longitudinal lines passing from the notches
between the teeth to the base, are borne upon peduncles about 3 mm. long with
several rings at the top. These rings seem to be fairly constant, two deep constrictions
giving rise to two ball-like divisions which are followed by an indistinctly ringed
portion of the peduncle, cut off from the remainder, which is smooth, by another deep
constriction.

Gonosome.—Not present.

Locality, ete.—Growing on Staurotheca reticuluta, Scotia Bay, South Orkneys.
Depth, 65 fathoms. Date, 25th March 1903.

The specimen approaches C. Hinksw (Alder, 1857), but the typical campanulate
form of the hydrothec, the blunt teeth, and the peculiar markings on the peduncle,
distinguish it from the parallel-sided hydrothece, the square-topped teeth, and the

TRANS. ROY. SOC. EDIN., VOL. XLV. PART II. (NO. 18). 74

928 MR JAMES RITCHIE

characteristic rmging of C, Hinksw, where the first annulation is included in the base of
the hydrotheca. From C, cylindrica, Allm., and C. tincta, Allm., it is also distinguished
by its campanulate form and its peduncle characters.

Obelia geniculata, Linnzeus, 1758.

Several specimens of this well-marked species were obtained growing on the fronds
of a large seaweed—Macrocystis pyrifera.

The hydrotheca-bearing shoots, which are generally simple and average only 12 mm.
in height, arise from a creeping stolon which ramifies over the surface of the seaweed
frond. The trophosome agrees with the description in Hinks’s British Hydroid
Zoophytes, but here the annulations on the peduncle are rather more variable—two or
three as well as a larger number being common. Within the hydrotheca, a short
distance from the base, a perisarcal ridge is well marked, supporting the flattened
basal portion of the polyp. Just above this bracket there occurs an irregular ring of
minute refringent spots—small prominences on the inner side of the hydrotheca wall—to
which the basal disc of the polyp is attached. These prominences resemble and serve
the same purpose as those found throughout the genus Haleciwm (vide p. 525). The
polyps are well preserved, and show well the large, trumpet-shaped proboscis.

Gronosome.—A bsent.

Locality, etc.—Growing on the fronds of Macrocystis pyrifera, Gough Island. Lat.,
40° 20’S.; long., 9° 56’ W. Date, 22nd April 1904.

Obelia longissima, Pallas, 1766.

A large number of weather-beaten colonies were found in the South Orkneys. The
specimens are about 8 cm. high and agree closely with Hinxs’s description and figures.
The hydrothecze are mostly awanting; those which remain are fragile and much
crushed, and probably as a consequence I was unable to detect the blunt teeth which
mark the rim. The pedicels, which taper towards the top, are usually altogether ringed,
but sometimes only in the proximal and distal regions, the median portion being smooth.
A pedicel was frequently noted springing from the axil between branch and branchlet,
as mentioned by Hinks (1868).

Subsequent specimens, residue from the seaweed collections, were in better
condition.

Gonosome.— Wanting.

Localities, etc.—(a) Macdougall Bay, South Orkneys. November 1903. (b) Off rocks
in shore-pool, Scotia Bay, South Orkneys. Temperature, 30° to 32°. Date, 6th December
1908.

The specimens from both localities appear to have been exposed to weathering for
some time. ‘Those from (b) especially show traces of rough usage, the branches being

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 529

broken off not far from their origin, while the greater number of the stems are covered

with polyzoon growths.

Silicularia henispherica = Hypanthea hemispherica, Allman, 1888.

The only representative of this genus in the Scotia collection occurs on the frond of
Macrocystis pyrifera, from Gough Island. The specimens bear out HarrLaus’s
opinion that the length of the peduncle, varying as it does to a considerable extent, is
not a safe specific character, for here various peduncles measure 6, 5, 4, 3, 1 mm.
In so simple a genus distinctive specific characters are not easily obtained, but the
following point to identity with S. hemispherica :—Hydrocaulus, creeping, branched,
bearing at varying distances pedunculate hydrothecee and gonangia which usually
alternate with one another. The peduncles are exceedingly variable in length, rather
less in diameter than the hydrocaulus, with a distal swelling, succeeded by a globular
seoment, and this in turn by the hydrotheca. The hydrotheca is conical, almost as
broad as long, about 0°7 mm. high by 0°5 mm. in greatest diameter, with a markedly
oblique margin.

The gonangia are 2 mm. long by 0°6 mm. in diameter, narrowing slightly towards
the opening, and considerably towards the base, where they are supported by a distinct
peduncle. They are never grouped on the hydrocaulus.

Locality, etc.—Creeping over the fronds of Macrocystis pyrifera, Gough Island.
Lat., 40° 20’ S.; long., 9° 56’ W. Date, 22nd April 1904.

Hebella striata, Allman, 1888. (PI. I. fig. 7.)

Several specimens of the beautiful species described by ALLMAN in the Challenger
Reports occur creeping on the stems and branches of various larger Hydroids. The
hydrothecee are large, almost 1 mm. in length by from 0°22 to 0°25 mm. in
diameter, cylindrical, borne on short, untwisted peduncles varying in length from 0°25
to 0-4 mm. In some the characteristic ringing exists only on the lower half of
the wall, part towards the margin being smooth. The hydranths are in all cases con-
tracted, and in this state oceupy only the lower half of the hydrotheca. They are in
good condition, and show in their contracted state a bulging body, separated from a
fleshy disc at the base of the hydrotheca by a marked constriction, and surmounted by
another constriction from above which arises a whorl of tentacles. Within the
tentacles there arises a conical hypostome.

Gonosome.—Not present.

Locality, etc.—Creeping on the stems and branches of Lafoéa gracillima, Grammaria
magellanica, Sertularella filiformis, Burdwood Bank. Lat., 54° 25’ S.; long., 57° 32’
W.; 56 fathoms. Ist December 1903.

530 MR JAMES RITCHIE

Hebella striata, var. plana, n. var. (Pl. I. Fig. 8.)

A colony creeping upon Haleciwm robustum, whose habit and general appearance
resemble those of H. striata. The hydrothecee, however, are rather larger, 1°3 to 1°4
mm. in length by 0°28 mm. in diameter, and show no hint of the annular thickenings of
perisare which form the characteristic striations. Marginal reduplications were noted
in some cases, while a solitary peduncle was marked by a thickened ring near its base.

Gonosome.—Not present.

Locality, etc.—Creeping on the stems and branches of Halecium robustum, from
Station 411. lLat.,74° 1’S.; long., 22° 0’ W. Depth, 161 fathoms. Surface tempera-
ture, 28°°9. 12th March 1904.

In none of the true H. striata colonies did there occur hydrothecee with more
than about a third of their surface smooth, the remainder of course being striated,
and even these were exceptional. Hence an entirely smooth hydrotheca seems worthy
of being considered a distinct variety.

Calycella syringa, Linneeus, 1758.

Arising from a tubular, creeping stolon are several minute, extremely delicate, almost
campanulate hydrothecze whose cavities are separated from those of their peduncles by
thin partitions. They are operculated, and are borne on peduncles of variable length
which are always marked by many strong annulations.

The absence of gonosomes and the unsatisfactory state of the hydranths render
accurate identification impossible, but the trophosome agrees with Hinks’s (1868)
description of C. syringa, except in that the “ horn-colour ” is lacking.

Measwrements.—Hydrotheca : length, including operculum, 0°2 mm. ; diameter, 0°1
mm. Pedunele: length, 0°2 mm.

Locality.—Burdwood Bank. Lat., 54° 25’ 8.; long., 57° 31’ W. 56 Fathoms.
1st December 1903.

Family Larokip2.
Lafoéa antarciica, Hartlaub, 1904.

The above species occurs on the stems and branches of Sertularella filifornus. It
agrees in all respects with the description given by Harriaus. The large number
of the regeneration rings on the hydrothecz is especially noticeable—six being not
unusual. The length of the hydrothecee, from where they leave the stem at right
angles, to the margin, averages 5 or 6 mm., while the diameter is about 1°25 mm.

Locality, etc.—Creeping on the branches of Sertularella filiformis, from Burdwood
Bank. Lat., 54° 25’S.; long., 57° 32’ W. Fathoms, 56. Date, 1st December 1903.

Previous Locality.—70° 23’ S.; 82° 47’ W.

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 531

Lafoéa gracillima (Alder, 1857).

Several specimens referable to this species occur growing on the horny axis of an
Aleyonarian. They agree in all but size with the specimens described by Bonnevir
(1899), the largest reaching a height of only 3 em., while the general size lies
between 2 and 3 em. The colonies are erect and branched, without any distinct
stem, the greater number of the branches lying in one plane and showing a tendency
to be more strongly developed on one side. Except towards the tip, where they are
monosiphonic, the branches are fascicled. The hydrothece are long narrow cylinders
05 mm. in length by 0°71 mm. in greatest diameter, sometimes with reduplication
rings round their margins. They arise irregularly from all sides of the hydrocaulus,
and are borne on loosely twisted peduncles bearing two turns of a spiral.

Gonosome.—Not observed.

Locality, etc.—Growing on the axis of an Aleyonarian (Gorgonid) in 56 fathoms.
Date, 1st December 1903. Burdwood Bank. Lat., 54° 25’ S.; long., 57° 32’ W.

Grammaria magellanica, Allman, 1888. (PI. I. figs. 4, 44.)

Three colonies varying in height from 6 cm. to 16 cm., and in breadth from 7 cm.
to 12 cm. The stem is fascicled and thick, reaching just above the base a diameter
of about 3 mm. and gradually tapering towards its summit. In two of the specimens
it divides about 1 cm. above the base into two or three equally developed, strong
branches, and these, together with the stem itself in the other specimen, bear along
their length usually alternate ramuli, which sometimes reach a length of 14 cm.
These primary ramuli bear secondary, and these again may bear tertiary, pinnee-bearing
branches. On all the branches, and on the main stem between the branches, there are
alternately-set pinnee usually between 10 mm. and 15 mm. in length, which become
greatly constricted at their point of origin. All the branches and pinnee lie in one
plane, and in the largest specimen anastomosis occasionally occurs between them. The
hydrothecee are placed in successive planes, in whorls of three, which alternate with
one another so that there are six longitudinal rows on the colony. They are cylindrical,
and have a circular opening with an even, non-everted margin.

Gonosome.—The gonangia are grouped together into irregular bunches which
surround portions of the stem and the bases of such branches as arise from these
portions. In the largest of the three colonies two bunches of clustered gonangia were
found, the larger 30 mm. long by 3 mm. in diameter, the smaller 20 mm. long by
about 2 mm. in diameter, while on another colony a still smaller cluster occurred.
These coppiniz are elongated clusters of compressed gonangia growing closely around
the stem for a considerable distance, and bristling with minute projecting tubes which are
without the irregular bendings figured by Harriavus (1905). Under the microscope the
cluster resolves itself into a large number of hexagonal cells, closely resembling honey-

532 MR JAMES RITCHIE

comb—the compressed gonangia—from among which spring many short, uncoiled tubes
0°4 to 0°5 mm. in length.

Locality.—Burdwood Bank. lLat., 54° 25’ 8.; long., 57° 32’ W. Depth, 56
fathoms. 1st December 1903.

As the species was named by ALiMaN from small fragments, and as subsequent
specimens collected by PaxEssLER in 1893 off Australia were also fragmental, | have
thought it necessary to give a rather full account of the structure of the colony to
supplement the original description. Since Harriavs figures only longitudinal and
transverse sections of the coppinia (HarTLauB, 1905, p. 597), representations of the
general appearance and magnified surface view have been here included.

Brucella, nov. gen.

We have named this genus after Mr Brucz, the leader of the expedition.

Generic Characters. Trophosome.—Stem and branches fascicled for the most
part, becoming monosiphonic distally; consisting of an axial tube predominantly
hydrotheca-bearing, surrounded by peripheral tubes which may occasionally bear
hydrothecee and nematophores. Hydrothece tubular, fastened by their bases to a
process of the hydrocaulus, their cavity being distinctly differentiated from that of the
peduncle. Hach hydrotheca is accompanied by a basal pair of nematophores.

Gonosome.—A coppinia, that is, a bunch of clustered gonangia surrounding the
hydrocaulus, from which a number of delicate tubes arise.

The genus shows aftinities with Perisyphonia, Allman (ALLMAN, 1888, p. 48) and
Zygophylax, Quelch (QUELCH, 1885, p. 4). From the former it can be distinguished
by its manner of fascicling, its arrangement of nematophores, and, perhaps not so
certainly, by the shape of the hydrothece. The chief points of difference are
summarised in the following table :—

Perisiphonia, Brucella.
Axial tube completely enveloped. Axial tube not completely enveloped.
No hydrothece on peripheral tubes. Scattered hydrothec on peripheral tubes,
Nematophores frequent and regular on peripheral Nematophores scattered and irregular on the peri-
tubes, pheral tubes.
Nematophores present or absent from axial Two nematophores at base of each hydrotheca on
tube. axial tube.
Hydrothece flask-shaped. Hydrothece tubular.

From Zygophylax, to which it is closely allied, it can readily be distinguished by
the distinct differentiation of the hydrotheca cavity from that of the peduncle, and by
the scattered nematophores on the peripheral tubes.

A portion of a specimen when softened in caustic potash and dissected, showed a
central, predominantly hydrotheca-bearing tube, surrounded by peripheral tubes, which
were sometimes simple, sometimes branched, and sometimes bearing scattered hydro-
theeee and nematophores. ‘The structure of the fasciculation seemed to resemble that

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 533

in Sertularella gayi as described by Nurrine, 1904, p. 6, although I found difficulty in
tracing the peripheral tubes to their origin. The peripheral tubes certainly never
become hydrotheca-bearing to the same extent as in Sertularella gayt.

The characters of the trophosome, and especially of the gonosome, appear to indicate
close relationship with the Lafoéidze, in which family the genus has accordingly been
placed.

Brucella armata, n. sp. (Pl. II. figs. 2a, 2B, 2c.)

Several specimens have been obtained of a colony for which the above new genus
has been formed. The colonies, which are erect and much branched, with both stem
and branches thickly fascicled, reach in some cases a height of 6 cm. by a
similar breadth. Owing to this great breadth, as compared with height, and to the
fact that the many branches lie in one plane, the colony assumes a somewhat flabellate
appearance. It is of a pale brown colour, becoming lighter towards the tips of the
branches. Except distally, where for a short distance they become monosiphonic, the
stem and branches are fascicled, consisting of an axial tube, predominantly hydrotheca-
bearing, surrounded by peripheral tubes which may bear occasional hydrothece and
scattered nematophores. The main branches, which may reach a length of 5 em., leave
the stem at irregular intervals, although frequently there is an approximation to
alternate arrangement, while those borne by the main branches are regularly pinnate
and alternate and are rarely branched. All the branches lie in one plane, and arise
from below a hydrotheca, which then lies in the axil of the branch. The cavity of the
axial tube is continuous; the tube is not divided into internodes, but bears
alternately at regular intervals small processes to which the hydrothecz are attached.
The hydrothece are biserial, alternate, tubular, with an entire margin which is not
parallel to the axis of the hydrocaulus. Their upper side is curved, while the lower is
almost straight, and their cavity is cut off from that of the rest of the colony by a
strong septal ridge at their junction with the hydrocaulus process. Above this occur
one or two delicate, membranaceous intrathecal septa apparently stretching across the
cavity of the hydrotheca, while near the edge there are usually two or three lines
indicating the presence of marginal reduplications. The length of the hydrothecse from
basal septum to margin is between 0°3 and 0°35 mm., while the greatest diameter is
from 0°13 to 0°15 mm. Towards the base they become constricted and rest upon a
short process of the hydrocaulus, from each side of which springs a nematophore.
The nematophores are small, only 01 mm. long by 0°04 mm. in diameter, and
resemble those found in some of the Hleutheroplean Plumularians, consisting of two
joints, the proximal, a narrow tube, the distal, a wider tube opening out slightly
towards the margin, round which there is frequently a reduplication line. This whole
two-joimted structure is sometimes loosely incased in an unjointed tube. Scattered
nematophores of similar structure occur frequently but irregularly on the peripheral
tubes, The form of the hydranth could not be distinguished.

534 MR JAMES RITCHIE

Gonosome.—On one specimen were found two clusters of gonangia, the larger
measuring 5 mm. in length by 3 mm. in diameter, the smaller 5 mm. by 2 mm. The
clusters or coppinie form elongated ovals surrounding the stem and the bases of
branches in the neighbourhood. They consist of numerous gonangia so closely packed
that the sides become compressed and the whole assumes a honeycomb-like structure
consisting of a dense mass of polygonal, usually hexagonal, cells, the majority of which
communicate with the exterior by an exceedingly short tube. Issuing from this
gonangial cluster are frequent tubes of various shapes; a few, especially at the ends,
are merely two-jointed tubes like cauline nematophores with their basal joint
elongated, while the majority consist of a longer tube 1 mm. in length bearing alternate
biserial nematophore-like bodies identical in structure with the nematophores on the
trophosome.

Locality, etc.—Growing on the axis of an Aleyonarian (Gorgonid), and dredged off
Gough Island, lat. 40° 20’8., long. 90° 56’ W., at a depth of 100 fathoms. Date,
22nd April 1904.

The colonies were growing on the horny axis of a Gorgonid Alcyonarian, and
appear to have been lying untenanted for some time, for not only has the coenosare
almost wholly disappeared, but foraminifera frequently occur within the hydrothece,
while barnacles and polyzoa, including a beautifully ringed, snake-like form, Anguinaria
spatulata—a rare British species—occur growing on the colony.

Family SERTULARIID.

Sertularella arborea, Kirchenpauer, 1884.

This species is represented by some colonies growing on lamellibranch shells, the
largest reaching « height of 8 cm. The specimens possess the characteristics described
by Hartriaus (1900) :—Compound stems and branches ; branches pinnate and alternate,
arising beneath a hydrotheca and divided by slanting nodes into very short, stout
unternodes, each of which bears a hydrotheca ; hydrothecee adnate for about two-thirds of
their length, with walls of unequal thickness and hints of imtracalycine teeth; margin
divided into four small, equal teeth. Gonotheca very long (about 3 mm.) and narrow,
often smooth, sometimes with faint signs of ringing, usually bearmg at the distal end
four minute teeth, and always arising from between the internode and the side of the
hydrotheca near the margin. The specimens show no variations which have not been
noted by Harriavs (1900).

Locality, etc. —Kntrance to Saldanha Bay, Cape Colony; 25 fathoms. Date, 21st
May 1904.

Sertularella contorta, Kirchenpauer, 1884.

Several specimens of this species have been obtained from two localities. They are
bushy colonies reaching to a height of slightly over 7 cm., almost destitute of branches

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 535

near the base, but. profusely branched distally. Except in the followmg unimportant
details, the specimens agree with those previously described. While the annulations
at the bases of the branches are well marked, the constrictions in the internodes are
neither so frequent nor so distinct as those of former specimens. The gonangia closely
resemble those described and figured by Nurrine (1904, p. 85). The annulations vary in
number, in some cases disappearing altogether in the proximal portion of the gonangium.
The teeth at the summit of the gonangium also vary in number; sometimes they seem
to be absent, as in KrRCHENPAUER’S specimen (1884), sometimes two are present, as
described by Nurrine, but in the present specimens three is also an occasional number.

Localities.—(a) Falkland Islands, Port Stanley. Date, 8th January 1903. (6)
Cape Pembroke ; shore. January 1903 to January 1904.

It is interesting to note that the present specimens were found in the same locality
as were those from which the original description of the species was made by KircHEN-
PAUER some twenty years ago.

Sertularella filiformis, var. reticulata, n. var.

Several colonies referable to this species have been found, usually growing on
polyzoon crusts, in two localities. Of the colonies, which are profusely branched and
loaded with gonangia, those from locality (a) reach a height of from 5 to 6 cm.
while those from (b) are considerably smaller. The hydrothecze are adnate to the stem
for 0°27 mm. and free for 0°15 mm., while at the opening their diameter is 0°15 mm.
They have three teeth, thus differing from ALLMAN’s (1888) description, where two broad
cusps are mentioned, and agreeing with Nurrine’s (1904) description of a portion of
ALLMAN’s specimen. The present specimens vary slightly from those described by
Norvine in habit and in gonangia. The majority of those from (a) and all the specimens
from (b) have closely interwoven and anastomosed branches, and thus present a matted,
net-like appearance.

Gonosome.—The gonangia arise from each side of and just below the hydrothecee.
They are top-shaped, 1°7 mm. long, with eight or nine large annular ridges, the widest
portion occurring about the second or third ridge from the distal end, where the
diameter, not including the ridge, is 0°7 mm. They are surmounted by a tube 0°45
to 0°5 mm. long, whose diameter gradually increases from base to margin, where it 1s
0°25 mm. wide.

Localities, etc.—(a) Burdwood Bank. Lat., 54° 25’ S.; long., 57° 32’ W.; 56
fathoms. Date, Ist December 1903. (b) Eight miles north of Dassen Island, Cape
Colony ; 35 fathoms. 18th May 1904.

Sertularella gayi, Lamouroux, 1821.

A strongly fascicled specimen 13 cm. high by 7 cm. broad is referable to this
species. The general habit of the colony, with rigid stem 2 mm. in diameter
TRANS. ROY. SOC. EDIN., VOL. XLV. PART II. (NO. 18). 75

936 MR JAMES RITCHIE

just above the base, and monosiphonic, roughly pinnate ramuli, is typical. The
hydrothecee are free distally for rather less than half their length, the free portion.
standing out from the stem almost at a right angle, and being marked on the upper
side by a few rather indistinct annular rugosities.

Fronosome.—Not present.

Locality, etc.—Depth, 100 fathoms. Off Gough Island. Lat., 40° 20’ S.; long.,
9° 56’ W. Date, 22nd April 1904.

Sertularella tenella (Alder, 1857).

Small specimens of this delicate colony some 7 mm. long have been found
growing on Synthecium robustum. They are quite typical in appearance, agreeing with
previous descriptions and figures.

The following are average measurements :—

Internodes.—Length from 0°55 to 0°8 mm.

Hydrothecee.—Length, 0°5 mm. ; widest diameter, 0°25 mm.; diameter at margin,
0°15 mm.

Gonosome.—Not present.

Locality, etc.—From off Burdwood Bank, lat. 54° 25’ 8., long. 57° 32’ W., at a depth
of 56 fathoms. Date, 1st December 1903.

Sertularella tricuspidata (Alder, 1856).

A slender, pinnately branched colony 7 cm. high. It lacks the profuse branching
and matted appearance of a typical specimen of S. tricuspidata, but in other respects it
agrees closely with the specific description.

Average Measurements.—Internodes: length, 0°75 mm. MHydrothece: height,
0°6 mm.; portion adnate, 0°35 mm.; portion free, 0°4 mm.; diameter at margin, 0°3 mm.

Gonosome.—Not present.

Locality, ete.—From off Burdwood Bank, lat. 54° 25’ S., long. 57° 32’ W., at a depth
of 56 fathoms. Date, 1st December 1903.

Sertularella rectitheca, n. sp. (PI. I. fig. 5.)

A small, delicate colony some 9 mm. high, growing on the stem of Stawrotheca
reticulata. ‘The stem is slender and unbranched, divided for some distance by slanting
nodes into short regular internodes 0°5 mm. long, and produced distally into a tubular
tendril-like process which was attached to a portion of the Staurotheca colony. The
internodes are much broadened half way up their length by a shoulder for the support of
the hydrothecze. These are alternate, cylindrical, about 0°5 mm. high by 0°15 mm. in
diameter, adnate up to the distal end of the internode in which they arise, then free for
the remaining third of their length. The hydrothece are straight, the free portion

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 537

being in the same line as the adnate, the whole axis lying practically parallel to the
‘stem. The margins of the hydrothecz are divided into three teeth, a small one on the
adcauline edge, and two large and equal ones on the margin remote from the stem.
The number of flaps in the operculum could not be counted.

Gronosome.—Not present.

Locality, etc.—Growing on Staurotheca reticulata, Scotia Bay, South Orkneys.
Depth, 65 fathoms. Date, 25th March 1903.

Thujaria pectinata, Allman, 1888.

A single specimen some 6 cm. high almost completely enveloped in a dense polyzoon
growth. The stem is unbranched and monosiphonic about | mm. across, and is divided
into equal internodes, each of which bears three pairs of opposite hydrothecee. A pair
of opposite pinnze arise from each internode, originating between the proximal and
median pairs of hydrothecee. On the pinne the nodes are quite distinct, being marked
by a constriction (in ALLMAN’s figure they are scarcely indicated), and the hydrothecze
are arranged as on the stem—three pairs to each internode. ‘The hydrothecee are so
closely approximated that the top of one touches the base of the next, but the “free
membranaceous extension of the wall” has in every case been destroyed, leaving a rather
rageed edge level with the general outline of the pinna. One of the pinne, instead of
being thecate to the tip, was produced into a long, tubular, tendril-like process.

Gonosome.—Not present.

Locality.—Dredged at the entrance of Saldanha Bay, Cape Colony, in 25 fathoms.
Date, 21st May 1904.

Synthecium robustum, Nutting, 1904. (PL. I. fig. 6.)

About half-a-dozen specimens of this species have been dredged from the locality
of Burdwood Bank. The average height is about 7 em., but two specimens are 11 cm.
high by 4 em. broad, almost twice the size of the specimen described by Nurrine.
The branches, which are regularly opposite, are simple in the majority of the
specimens, but in some they rarely bear opposite branchlets; and not only in these
branchlets, but even in the branches themselves, there is a distinct narrowing of the
perisare immediately above each pair of hydrothecee. The hydrothece have frequently
one or two annular striations—lines of reduplication—round their margins. Except in
these details the trophosome agrees with Nurrine’s description.

Gonosome.—The gonangia differ somewhat from the dried specimens originally
described. They are top-shaped, 2 mm. long by 1 mm. in diameter at the widest part.
Distally they are strongly annulated, proximally they are almost smooth, while they
are terminated by a low dome, the tubular neck of the original specimen being

unrepresented.

KS) |)! 5 MR JAMES RITCHIE

Locality, etc.—-Burdwood Bank. Jat., 54° 25’ 8.; long., 57° 32’ W. Depth, 56
fathoms. 1st December 1903.

The occurrence in these specimens of branches sometimes simple and sometimes
bearing pinnately arranged branchlets, appears to indicate that this character, upon
which Harriaus founded his S. chilense (1905, p. 671), is rather a variation than a
character of specific value.

Staurotheca, Allman, 1888 (modified).

Generic Character. Trophosome.—Hydrocaulus fascicled or unfascicled, bearing
hydrothecze in longitudinal rows and arranged in a series of transverse planes, each
plane containing two or three hydrothece which exactly alternate with those im the
planes above and below them.

Gonosome.—Gonangia simple capsules springing from the hydrocaulus and destitute
of marsupium.

This genus, as described by ALLMAN, must be slightly modified to include the
specimen described below. The alternate arrangement of the successive series of
hydrothecee remains constant, but the generic characters must be widened to include
not only opposite hydrothecee, but also hydrothecee arranged in whorls of three.

Staurotheca reticulata, n. sp. (PI. I. figs. 1, 1a, 1B.)

A portion of a branched hydroid colony 8 cm. in length by 4 cm. in breadth.
The stem, which is 0°5 mm. in diameter, is unfascicled, and from it arise, at fairly
regular intervals of 5 mm., alternate flexuous branches of the same thickness as the
stem, which zigzags between their bases. Smaller branches arise from these main
branches and anastomose so frequently, sometimes by means of short, tendril-like
processes, that free ends are absent except towards the margin of the colony. In some
cases the free ends develop hydrorhizal tubes. All the branches lie in one plane, and
this, together with the flabellate form of the colony and the prevalent anastomosis, gives
the whole a remarkable net-like appearance, the regularity of the meshwork, at least
near the stem, being increased by the fact that the main branches on each side of the
stem lie roughly parallel. The internodes are irregular, generally containing about
three pairs of hydrothece in the older branches, while in the younger there is usually
a hint of a node between each pair.

The hydrothecee are placed in longitudinal rows along the stem and branches. In
the majority of the branches there are four rows, the hydrothece being arranged in
opposite pairs, which are placed alternately at right angles with one another. Sometimes
there are six rows—the hydrothecze in this case being placed in a succession of trans-
verse planes, each plane containing three equidistant hydrothecee, which exactly alternate
with those in the planes immediately above and below them. The hydrothece them-
selves are cylindrical and deep, with a circular orifice and a smooth margin marked

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION, 539

sometimes by one or two lines of growth. They are 0°5 mm. in height, and for 0°4 mm,
of this distance they are adnate, the free portion curving outwards from the stem.

Gonosome.—The gonangia are ovoid, 0°7 to 0°8 mm. long, and 0°45 mm. in diameter
at the widest part, narrowing proximally and terminated distally by a circular orifice
at the end of a short bulging prominence. They lie closely apposed to the stem for
the greater part of their length, but can easily be detached, and arise on each side of,
and just below, a hydrotheca. Thus although one or two gonangia most commonly
occur at one level, the full complement at a plane containing a pair of hydrothece is
four, two to each hydrothece.

The colony is of a horn brown colour.

Locality, etc.—Obtained from a gripper on a sounding wire from Scotia Bay, South
Orkneys. Depth, 65 fathoms. Date, 25th March 1903.

Family PLUMULARIIDé.
Aglaophenia dichotoma (Johns.), Kirchenpauer, 1872. (PI. III. figs. 2, 2a, 2B, 2c.)

A large number of branched, fan-shaped colonies, 10 cm. high by about 7 em.
broad, with monosiphonic stems. The following details supplement KiRcHENPAUER'S
rather meagre description :—The branching, which is characteristic, is strictly dich-
otomous. The stem and branches are divided into short regular internodes 0°3 mm.
long, and from a nematophore-bearing process on each of these a hydroclade arises.
The hydroclades, which are alternate and closely approximated, are borne on the front of
the stem and leave it at an angle of about 45°. They also are divided into short regular
internodes 0°3 mm. in length, each with two strong septal ridges extending almost around
their walls, one opposite and in line with the intrathecal septum, the other at the
level of the bases of the supracalycine nematophores. The hydrothecx, which are closely
approximated and obconical, are tilted forward from the stem, the distal portion appar-
ently being free. Their margin, which is not expanded or flaring, is divided into
nine teeth, the anterior three being slightly larger and sharper, the middle one bent a
little backwards. The intrathecal ridge is strong and oblique, in the same line as the
corresponding internodal ridge, and reaching to the opposite wall of the hydrotheca.
The supracalycine nematophores are not quite tubular. They are large and bulging, but
do not reach to the margin of the hydrotheca, while the mesial nematophore, which is
extremely narrow near the base but becomes wider distally, just reaches the level of the
margin, the distal third of its length being free. The process arising from the stem
and branch internodes, upon which the hydroclades are borne, bears about five
nematophores similar in structure to those on the hydrotheca. The arrangement also
is similar, one being median and proximal, while two are lateral and near the distal
end of the process, but there are in addition a lateral and a basal pair.

Gonosome.—The corbula is oval, flattened laterally, 2 mm. long by 1 mm. in

540 MR JAMES RITCHIE

greatest diameter. It has five pairs of adnate costee, each bearing from ten to twelve not
quite tubular denticles along its length and an apparently. unpaired, partly free, costa at
the proximal end. On the corbula peduncle there is one hydrotheca.

Locality, etc.—The colonies were growing on a sponge, and were dredged at the
entrance to Saldanha Bay, Cape Colony, in 25 fathoms of water. Date, 21st May 1904.

Plumularia echinulata, Lamark, 1836.

Several colonies, the largest 3 cm. in height, were found growing on sponges in the
same locality as P. pinnata. The specimens differ somewhat from the type described
by Hinks (1868) but seem to form a connecting link between P. echinulata, type
and P. echinulata, var. pinnatirdes of BrtuarD (1904, p. 191 et seq.). The following
points indicate a close relationship to the latter:—Stem internodes in the proximal
portions of the colony sometimes bearing two hydroclades, while in the distal internodes,
and more generally throughout the colony, only one hydroclade per internode is the
rule ; intermediate internodes in the hydroclades absent in the specimens examined ;
supracalycine sarcostyle unprotected by a nematotheca, as described by Hinks;
hydrothecee deep; gonangia borne on stem. On the other hand, the fact that the
margin of the hydrotheca does not reach the level of the succeeding node, and the
presence of well-marked and frequent spines on the gonangia, indicate affinities with
BILuarp’s type.

The state of the material prevented observations on the condition of the axillary
nematophores from being made.

Locality, etc. — Growing on sponges, coaling jetty, Cape Town Docks. May
1904.

Plumularia magellanica, Hartlaub, 1905. (Pl. II. fig. 1, 14.)

The specimens collected by Mr Bruce differ somewhat in the structure of their
hydroclades from the specimens of this peculiar species described by Harriaus, but
the difference is not of specific value. As in Harriaus’s case, material is scarce.

The most complete colony is 15 mm. in height, and consists of a stem 0°15 mm. in
diameter, divided by straight nodes into irregular internodes, each of which bears near
its middle a single hydroclade. The hydroclades arise alternately from the stem nodes
and are comparatively short — about 1 mm. They are set upon a small process of
the stem, from which the first thecate internode is separated by a narrow, somewhat
ring-like, athecate internode with slanting nodes. The thecate internodes are narrow at
the base, and gradually widen distally until they finally seem to end in a rather shallow
cup with expanded walls. From below this cup, and free from it, there arises in the
distal portions of the colony a single short process, which bears again an expanding
thecate internode from beneath whose hydrotheca another free process is given off, and
so on, until each hydroclade bears from two to four or even five hydrothece. The

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 541

marked angle at which each thecate internode lies with regard to the one preceding it,
gives these simple distal hydroclades a helicoid-eyme-like appearance. In the proximal
hydroclades—and here our specimens differ from Harriaus’s—two processes arise below
and at the opposite sides of the first hydrotheca, each of which bears a thecate internode,
so that after the first hydrotheca the hydroclade possesses two diverging branches each
similar to the simple distal hydroclades. Since the double hydroclades arise laterally
and not dorsally, as HarrLavs describes, from their internode, it follows that their
origins lie in a plane at right angles to the plane of the primary stem processes. The
hydrothece are shallow, with delicate, slightly expanded walls, and smooth margins. They
appear to terminate the internode which bears them, are fixed only by their bases to
their internode, and their walls are free. A single delicate, shovel-like nematophore lies
in the centre of the internode beneath each hydroclade.

Gonosome.—Not observed.

The structure of the whole colony is extremely delicate. In some cases the
hydrothecal and internodal walls collapsed in process of mounting for microscopic
examination.

Locality, ete—Growing on a sponge, Port Stanley, Falkland Islands. 3rd February
1904.

Previous Localities.—South of Tierro del Fuego and Island Pictou, Tierro del
Fuego Archipelago.

Plumularia pinnata, Linneeus, 1758.

A number of colonies, the largest only about 4 cm. high, oceur on sponges and on
lamellibranch shells. The colonies agree with Hinxs’s description. The following
variations were noted in the specimens :—-Generally the number of hydroclades per
internode is two, but on a number of the distal internodes only one hydroclade occurs.
The presence of a basal athecate internode at the origin of each hydroclade, as described
by Britarp (1904, p. 204), was noted, but between the thecate internodes no inter-
mediate athecate internodes were observed.

Gonosome.—While the proximal, and therefore the older, gonangia assumed the
spinous form figured by Hinks (1868, PI. 65), the distal, younger gonangia were some-
what cup-like, with a truncated appearance, due to the inversion of the topmost portion
of the gonangium, which, at first inverted, apparently becomes everted in the later
stages of growth.

Locality, etc.—Growing on sponges and on lamellibranch shells, coaling jetty,
Cape Town Docks. May 1904.

Plumularia wnilateralis, n. sp. (Pl. I. ialersy ly IA, la, IC.)

The specimens for which this species has been formed are small, averaging only
2 cm. in height, with simple recurved stems divided by slanting nodes into regular
internodes, in general 0°4 mm. in length, but rather longer towards the base. From the

542 MR JAMES RITCHIE

middle of each internode there arises a single hydroclade. In no case has more than
one hydroclade per internode been seen. The hydroclades, which are set on short
processes of the stem internodes, lie alternately in two planes, these planes being
so set forward that the hydroclades appear to arise from only one side of the
stem. They leave the stem at acute angles (30° to 45°), and are divided into
equal internodes 0°25 mm. long, each of which bears a hydrotheca—one small triangular
athecate internode separating the first thecate internode from the stem process In
some cases secondary hydroclades are developed from the side of a hydroclade inter-
node at the level of the base of the hydrotheca. No internodal septee are present,
but the internode bulges proximally to form a support for the hydrotheca. The
hydrothece are cup-shaped, moderately deep, even-rimmed, and for a short distance
distally they are free from the internode. They are closely approximated, the margin
of a hydrotheca being on a level with the succeeding node. Nematophores are absent
from the stem, from the stem processes, and from the athecate internodes at the origin
of the hydroclades, but one small, shovel-shaped nematotheca occurs in the median
portion of the internode just below each hydrotheca, while in the angle between the
hydroclade and the free rim of the hydrotheca is a median, unprotected sarcopore.

Gonosome.—Gonothece about 1 mm. in length occur in parallel rows along the
stem, apparently arising on the inner side of the hydroclade-bearing processes. They
are ovate, with somewhat flat tops, and are very shortly stalked. The gonothece are
seldom smooth, the walls being generally strengthened by seven regular longitudinal
ridges, which terminate distally in one or two more or less pronounced spines.

Locality, etc.—Growing on a sponge from the entrance to Saldanha Bay, Cape
Colony ; 25 fathoms. Date, 21st May 1904.

Antennularia hartlaubr, n. sp. (PL HL fig. 4, 44, 48.)

Colonies growing on a sponge in thick bunches, with thick fascicled stems which,
about | cm. from the base, break up irregularly into smaller, still fascicled branches,
these finally breaking up into long simple twigs. The latter are divided by straight nodes
into regular internodes 0°5 mm. long, each of which bears three equally distant hydro-
clades so arranged that those on one internode exactly alternate with those on the
internodes above and below, a hexastichous arrangement thus being produced. The
hydroclades are borne on stout processes of the branch internodes 0°15 mm. long, and
are divided into unequal internodes which are alternately long and thecate and short
and athecate—two athecate internodes separating the first thecate internode from the
supporting process. Sometimes, however, two athecate imternodes are developed
between a hydrotheca-bearing pair. Hach internode is marked by two strong internal
septa, one proximal, the other distal; but in the longer internodes two more are
sometimes developed, one opposite the base of the hydrotheca, the other a little lower.
The hydrothece are shallow, even-rimmed, resting on a broad ledge of the internode

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 543

and free for a short distance distally. The nematophores, of the usual trumpet-shaped
type, have an internal septum which gives them a two-jointed appearance and are
arranged as follows :—Three on each thecate internode, two lateral and distal, and reaching
a considerable distance above the level of the hydrotheca margin, the other median and
proximal and arising just above a slight bulge in the internode; one on each athecate
internode, except where two such internodes are developed in succession, when the
proximal one is unprotected ; on the branches there are two lateral nematophores on
the hydroclade-bearing process and one in the angle between this and the branch, but
in the next highest internode.

Gonosome.—Not observed.

Locality, etc.— Entrance to Saldanha Bay,Cape Colony,in 25 fathoms. 21st May 1904.

The present specimens approach in general structure A. decussata, Kirch. (1876, p. 55),
A. johnston, Kirch. (1876, p. 55), and A. wregulares, Quelch (1885, p. 8), for in the first
and last of these the hydroclades, although generally two in number per internode, may
vary from two to three or even four. In our specimens the hexastichous arrangement
appears to be constant, and the species is distinguished from those mentioned above in
having exceedingly strongly developed internodal septa.

We have named the above form after Professor CL. Hartiaus of Heligoland, author
of the report on the Belgian Antarctic Expedition hydroids, to whom we are indebted for
occasional assistance.

Antennopsis scoti#, n. sp. (PI. LI. figs. 8, 3a.)

Two much weather-beaten colonies of a pale brownish colour, growing on a sponge
fragment and reaching a height of 9 em. and 4 em. respectively. Both the colonies are
badly weathered ; the smaller is overgrown for half its length by the sponge, while the
remaining portion is destitute of hydroclades. Here and there at irregular intervals a
branch springs from the main stem, but without any definite arrangement. Of the larger
specimen about 5 cm. are free from the encircling sponge, and on this almost bare surface
a few hydroclades occur. The stem and branches are strongly fascicled, about 2 mm. in
diameter, but the coenosarc shows no signs of caniculation (NuTTING, 1900, pp. 68 and
72). The hydroclades arise irregularly from all sides of the stem, springing from
the outer tubes of the fascicle. Proximally they have from three to six athecate
internodes separated by straight nodes, the distal of these, and sometimes that
beneath it, being greatly elongated and bearing a number of nematophores varying from
two per joint to five on a single long internode. Above this athecate portion the
hydroclade is divided by alternate slanting and straight nodes into fairly regular
internodes, every alternate one of which bears a hydrotheca. The hydrothece are
stoutly campanulate and large, 0°22 mm. in length by 0°22 to 0°25 mm. in greatest
diameter, with entire rim and oblique opening, adnate up to the distal end of their own
internode, and afterwards free—the free portion lying over against the intermediate
internode, the rim reaching the level of the proximal end of the next hydrotheca-

TRANS. ROY. SOC. EDIN., VOL. XLV. PART IT. (NO. 18). 76

544 MR JAMES RITCHIE

bearing internode. They are thus closely approximated. The nematophores have a
widely expanded, trumpet-shaped mouth, and besides those already mentioned, there
are three on each hydrotheca-bearing internode, one median and proximal, standing
on a slight angle of the internodal perisare, two lateral, each borne on a process which
rests against the side of the hydrotheca. Only one nematophore occurs on each
intermediate internode,

Gonosome.—Not observed.

Locality, etc.—Dredged at the entrance of Saldanha Bay, Cape Colony, in 25 fathoms.
Date, 21st May 1904.

The general architecture approaches that of Antennopsis fascicularis (ALLMAN,
1883, p. 24), but there are differences in the proximity of the hydrothecee and in the
number and distribution of the nematophores.

We have named this species after the Scotea—the ship of the Scottish National
Antarctic Expedition.

LIST OF LITERATURE CITED.

Auper, 1856. Annals and Magazine of Natural History.
,, 1857. “A Catalogue of the Zoophytes of Northumberland and Durham,” in Zrans. Tyneside
Naturalists’ Field Club.
Autman, 1876. Ann. and Mag. of Nat. Hist., 4th ser., vol, xvi.
. 1883. ‘‘Report on the Plumularians of the Challenger Expedition,” Se. Reports, Zool., vol. vii.
3 1888. “Report on the Hydroids of the Challenger Expedition,” Part II., Se. Reports, Zool.,
vol, xxiii.
BitnarD, 1904. ‘Contributions a l’étude des hydroides,” in Annales des Sc. Nat., vol. xx.
Bownevig, 1899. he Hydroida of the Norwegian North-Atlantic Expedition 1876-78. Christiania, 1899.
Harrnaus, 1900. “Revision der Sertularella-Arten,” in Abh. naturw. Ver. Hamburg, vol. xvi.
5 1904. ‘‘Hydroiden,” in Résultats du voyage du S.Y. ‘‘ Belgica” en 1897-99.
a 1905. “Die Hydroiden der magalhaensischen Region und chilenischen Kiiste,” in Fauna
Chilensis—Supplement VI. to the Zoologische Jahrbiicher.
Hinks, 1861. ‘A Catalogue of the Zoophytes of Devon and Cornwall,” in Ann. and May. of Nat. Hist.,
vol. x1.
» 1868. A History of the British Hydroid Zoophytes.
Jounstong, 1847. A Hist. of the Brit. Zoophytes, 2nd ed.
Krrcnenpauer, 1872. ‘‘ Ueber die Hydroidenfamilie Plumularide,” Part I. Aglaophenia.
- 1876. Jbid., Part II. Plumularia u. Nemertesia, in Abh. naturw. Ver. Hamburg, vol. vi.
a 1884. ‘Nordische Arten und Gattungen von Sertulariden,” ¢béd., vol. viii.
Lamark, 1836. Hist. Nat. des animaux sans vertebres, 2nd ed. Histoire des Polypes, Paris.
Lamouroux, 1821. Exposition méthodique des genres de Vordre des polypiers, Paris.
Linnaus, 1758. Systema Nature, ed. 10.
Nurtine, 1900. ‘American Hydroids,” Part I. Plumularide, in Spec. Bulletin Smithsonian Institute.
5 1904. Jbed., Part II. Sertularide, cbed.
OrrMANN, 1896. Grundziige der marinen Thiergeographie, Jena.
Patras, 1766. Elenchus Zoophytorum, Hague.
QuetoH, 1885. Annals and Mag. of Nat. Hist., ser. v. vol. xvi.
Sars, 1846. Fauna Littoralis Norvegix, vol. i.

ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION, 545

eo bt bo bo be
5 o 5

mem H OO
Sees

iP

ome

EXPLANATION

Staurotheca reticulata, n. sp.

” 0

” 32
Campanularia, sp.
Halecium interpolatum, n. sp.
Grammaria magellanica, Allm.

” ”

Sertularella rectitheca, n. sp.
Synthectum robustum, Nutt.
Hebella striata, Allm.

ss var. plana, n. var.

Plumularia unilateralis, n, sp.

Halecium interpolutum, n. sp.
Halecium tenellum, Hinks.

Plumularia magellanica, Hart.

” oh)

Aglaophenia dichotoma (Johns.),

Antennopsis scotizx, n. sp.
” bP}
Antennularia hartlaubi, n. sp.
” bP)

” ”

OF PLATES.

Pratt I,

Nat. size.

Portion of stem and branch showing hexastichous and decussate
arrangements of hydrothece.

Portion of branch with gonangia.

Nat. size.
Nat. size, showing gonosome cluster.
Surface of gonosome cluster.

Gonangium.
Hydrotheca not completely ringed.

Puate II.

Nat. size, growing upon a sponge fragment.

Stem with hydroclades.

Gonangia.

Portion of hydroclade with hydrothece.

Nat. size, showing coppinia cluster.

Surface of coppinia cluster.

Portions of a fascicled and an unfascicled branch, with a creeping
polyzoon—Anguinaria spatulata.

Hydrothece.

Branch, with hydrothece, ending in stolons,

Showing attachment of hydranth within hydrotheca.

Prats III.

Origin of a double hydroclade.

Nat. size.

Corbula.

Hydrothece.

Portion of stem, showing origin of hydroclades.

Nat. size, partially encircled by a sponge.

Hydroclade with hydrothece.

Nat. size.

Hydroclade with hydrothece.

Stem showing hexastichous arrangement of hydroclades.

Trans. Roy. Soc. Edin® Vol. XLV.

IRimGEnD: “SCOMN Ishiwiouye,—— Pinaara, I

Nor : » Lith Edin
Jas Ritchie .del M‘Farlanc & Erskine Lith Edin’

Trans. Roy. Soc. Edin™ Vol. XLV.

RITCHIE: SCOTIA HYDROIDS.— PLATE II.

Jas. Ritchie, del. 5
a itchie, de Marlene & Erskine Lith. Edin?

Teams. Rowe SOG, Iohinn Vol. XLV.

RimcEeuae SGowwN lehvpyrOmpDs—— Iwai Jun,

Jas. Ritchie, del. Mifarlane &Erskine, Lith Edin?

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