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MEMOIRS

OF THE

MUSEUM OF COMPARATIVE ZOOLOGY

HARVARD COLLEGE.

VOL. XXXIX.

_ bea
Ab.l-

CAMBRIDGE, MASS,., U. S. A.
Printed for the Auseum.

1908-1920.

CONTENTS.

. 1— REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE

TROPICAL PACIFIC, IN CHARGE OF ALEXANDER AGASSIZ, BY THE U.S.
FISH COMMISSION STEAMER “ALBATROSS,” FROM AUGUST, 1899, TO
MARCH 1900, COMMANDER JEFFERSON F. MOSER, U. 8S. N. COMMAND-
ING. XI. ECHINI. THE GENUS COLOBOCENTROTUS. By ALEXANDER
Acassiz. 49 plates. November, 1908

. 2— REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE

TROPICAL PACIFIC, IN CHARGE OF ALEXANDER AGASSIZ, BY THE U.S.
FISH COMMISSION STEAMER “ALBATROSS,” FROM AUGUST, 1899, TO
MARCH, 1900, COMMANDER JEFFERSON F. MOSER, U.S. N., COMMAND-
ING. XV. ECHINI. ECHINONEUS AND MICROPETALON. By A. M.
WESTERGREN. 31 plates. August, 1911

. 3.— REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE

EASTERN TROPICAL PACIFIC, IN CHARGE OF ALEXANDER AGASSIZ,
BY THE U.S. FISH COMMISSION STEAMER “ALBATROSS,” FROM OCTO-
BER, 1904, TO MARCH, 1905, LIEUT. COMMANDER L. M. GARRETT, U.S. N.,
COMMANDING. XXXII. ASTEROIDEA. By Huserr Lyman Cuark. 6
plates. February, 1920

. 4— REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE
TROPICAL PACIFIC, IN CHARGE OF ALEXANDER AGASSIZ, BY THE U.S. ~

FISH COMMISSION STEAMER “ALBATROSS,” FROM AUGUST, 1899, TO
MARCH, 1900, COMMANDER JEFFERSON F. MOSER, U.S. N., COMMAND-
ING. XXII.

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE

EASTERN TROPICAL PACIFIC, IN CHARGE OF ALEXANDER AGASSIZ,
BY THE U.S. FISH COMMISSION STEAMER “ALBATROSS,” FROM OCTO-
BER, 1904, TO MARCH, 1905, LIEUT. COMMANDER L. M. GARRETT, U.S.N.,
COMMANDING. XXXIII. HOLOTHURIOIDEA. By Husert Lyman Crarx.
4 plates. September, 1920

69

115

~~

Hlemorrs of the Museum of Comparative Zoologn
AT HARVARD COLLEGE.

iWon. XGXeXhxX.” Nos dt:

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE
TROPICAL PACIFIC, IN CHARGE OF ALEXANDER AGASSIZ, BY THE
U. S. FISH COMMISSION STEAMER ‘“ ALBATROSS,” FROM AUGUST,

1899, TO MARCH, 1900, COMMANDER JEFFERSON F. MOSER, U.S. N.,
COMMANDING.

xT,
ECHINI.

THE GENUS COLOBOCENTROTUS.

By ALEXANDER AGASSIZ.

WITH FORTY-NINE PLATES.

[Published by Permission of Gzorce M. Bowers, U. S. Commissioner of Fish and Fisheries.]

CAMBRIDGE, U.S. A.:

Printed for the Museum,

NovemBer, 1908.

.

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7

CONTENTS.

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE
TROPICAL PACIFIC, in charge of ALexanpER AGassiz, by the U. S. Fish Com-
mission Steamer ‘‘ Albatross,” from August, 1899, to March, 1900, Commander
JEFFERSON F. Moser, U. 8. N., Commanding. XI. Ecntnr: Tur Genus Coxogo-
cenTRoTUS. By ALEXANDER AGassiz. With viii., 33 pp. and 49 Plates.

TABLE OF CONTENTS.

PacE PaGE
NOUR Spans «: Soyo" Sago! tow pial Podophora atrata Agass.; Plates 2,
Colobocentrotus eine 1 figs. 1-3; 3°, figs. 5-8; 16, figs.
Colobocentrotus Mertensii Br. 1 9-14 ; 17-28, 31, figs. 6-8. . . . 14
Colobocentrotus Stimpsoni A. Ag. . 1 Podophora pedifera Agass.; Plates 1,
IRodophora; Agasssaa en Tn een 2 3°, figs. 7-4; 4-16, figs. 1-8; 31,
Podophora atrata Agass. . 2 the ih a Boe s if)
Podophora pedifera Agass. . 2 | The Lanterns and Auricles of Giese
Colobocentrotus and Podophora 3 trotus and Podophora; Plates 13-15,
Colobocentrotus Mertensii Br. ; Plates 26-28,44 ..... So
2, figs. 8-13 ; 3%, figs. 9-11; 30, 32, The Spicules of the Podivelne Plates
figs. 5-8 ; 35, 36, 39, figs. 3, 4; G4) Ge cg ec 26
44, 45, figs. 6-10 . hee . 7 | The Pedicellarie; Plates 37-6; 17-19;
Colobocentrotus Stimpsoni A. cae. ; FAS) Gil) 27
Plates 2, figs. 4-7 ; 29, 32, figs. 1-4 ; The Spheridia, Plates 31, 32, a Gystas
33, 34, 37, 38, 39, figs. 4-5 ; 40-45, canths, Plates 1=3). . .-.-.. . 30

figs: 1-05. away eee ee eee

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NOTE.

———

A small number of sea-urchins were collected during the Tropical Pacific
Expedition of the “ Albatross” (1899-1900), so that only a few genera and
species characteristic of the Pacific will be described in succession whenever
sufficient new and interesting or important material has been obtained.

The genus Colobocentrotus of Brandt remarkable for its peculiar primary
radioles forms the subject of the first part of the Tropical Pacific Echini.
This will be followed by a paper on the allied genus Heterocentrotus.

I have to thank Mr. Richard Rathburn of the Smithsonian for having sent
me for study the types of Colobocentrotus collected at the Bonin Islands, by
Dr. Wm. Stimpson, the naturalist of the North Pacific Exploring Expedition
under command of Captains Ringgold and Rodgers.

I am greatly indebted to Mr. Magnus Westergren for the interest he has
taken in the preparation of the Plates illustrating this Memoir. His accuracy
in drawing, his knowledge of the structure of sea-urchins obtained during his
long training in the preparation of plates on Echinoderms, is shown on every
plate due to his facile pencil.

In addition to the material of Colobocentrotus collected by the “ Alba-
tross ” during the Tropical Pacific Expedition I have availed myself of mate-
rial collected by the “ Albatross” at the Hawaiian Islands and in other parts
of the Pacific and in the Indian Ocean, found in the collections of the Museum
of Comparative Zoblogy.

ALEXANDER AGASSIZ.
Newrort, R. 1, August 29, 1908.

TROPICAL PACIFIC ECHINI.
THE GENUS COLOBOCENTROTUS.

CoLoBocENTROTUS Brandt (A. Ag. emend.).

Colobocentrotus Brandt, 1835, Prod. p. 66.
Colobocentrotus A. Ag. Rey. Echini, p. 423 (partim).

This genus is now limited to such species as Colobocentrotus Mertensii
Brandt and Colob. Stimpsoni A. Ag., the better known species, C. atratus and
C. pedifer, having been separated from it and united in the genus Podophora
Agass.

The following are the species of Colobocentrotus and of Podophora
described in this memoir:

Colobocentrotus Mertensii Brandt.

Colobocentrotus Mertensii Brandt, 1835, Prod., p, 66.

Colobocentrotus Mertensii A. Ag. (partim) Rev. Echini, 1872, p. 103, Pl. III‘, figs. 4, 5,
p. 426. Bonin Islands.

Colobocentrotus Leskei A. Ag. 1863. Proc. Phila. Acad. p. 354 is a slip of the pen for
Colobocentrotus Mertensii Brandt.

Colobocentrotus quadriseriatus Trosch.,noted by Troschel as occurring in Australia, is, I
should say from his description, Colob. Mertensii Brandt.

This species was collected by Dr. Wm. Stimpson at Port Lloyd, Bonin
Islands, North Pacific Exploring Expedition, under Captains Ringgold and
Rodgers. It is figured in the Revision of the Echini, Plate III’, figs. 4, 5.

Stimpson says it is found “in surf-washed rocks.”

Colobocentrotus Stimpsoni A. Ag.

Is the large grayish pink species collected by Dr. Stimpson at the Bonin
Islands, North Pacific Exploring Expedition, and described later on.
The species of Colobocentrotus have thus far only been collected at the

Bonin Islands and, according to Troschel, in Australia.
1

bo

TROPICAL PACIFIC ECHINI.

PoporHora Agass.
Podophora Agass. 1840, Cat. Syst. Ectyp., p. 19.

In 1840 Agassiz was not aware of the existence of Brandt’s Prodromus
where the genus Colobocentrotus was established.

Podophora atrata Agass.

Echinus atratus Lin. 1758, Syst. Nat. ed. X., p. 655.

Echinometra atrata Blainv., 1834, Actinol., p. 225, Pl. 20, figs. 1, 1a.

Podophora atrata Agass. 1840, Cat. Syst. Ectyp., p. 19.

Colobocentrotus atratus A. Ag. (partim), 1872, Rev. Echini, p. 102, Pl. I1I%, fig. 3.
Colobocentrotus atratus Mobius, 1908, Aesthetik d. Thierwelt, fig. 5, p. 20.

Lovén in his Echin. of Lin. says that the type of Linnzeus was collected at
Mauritius, or rather that the original of the figure in the French edition of
Klein to which Linneus refers in his twelfth edition came from Mauritius.
Leske’s figure, to which Blainville and others refer as the typical atratus, has
the longer marginal spines rounded at the tip. Blainville further states that it
is “d’un blanc violet presque noir,” which agrees with the coloring of the spe-
cimens from the Hawaiian Islands and Mauritius in the Museum collections.

Hawaiian Islands, M. C. Z. collections.

Hilo, Hawaii, Smithsonian (Albatross coll.).

Mauritius, Seychelles, Zanzibar, M. C. Z. collections. This species has also
been noted as occurring at Java and the Moluccas. '

Mobius has given an excellent figure of Podophora atrata from Mauritius,
the dark violet species with long spines rounded at the tip. Hchinometra
(uoyi Blainy. is only the young of P. atrata. Colob. Leskei Br. is probably
P. atrata.

Podophora pedifera Agass.

Echinus pedifer Blainv. 1825, Dict. Sc. Nat. O., Vol. 37, p. 97. Mers Australes.
Podophora pedifera Agass., 1846, C. Rais. Ann. Se. Nat. VI, p. 370.
Podophora atrata A, Ag. (partim), 1872, Rev. Ech. p. 102, Pl. III‘, fig. 3, p. 424.

The excellent description of Blainville, with his statement “couleur géné-
rale d’un vert bleuatre, les mammelons verts, les épines livides,” leaves no
doubt of its identity with the greenish-olive specimens collected at Fakarava

1 See Rey. Echini, 1872, p. 103.

THE GENUS COLOBOCENTROTUS. 3

by the “Albatross” Tropical Pacific Expedition 1899-1900, on the seaface of
the reef exposed to the full force of the surf.

A specimen from Chili is figured in the Revision of the Echini (PI. III‘,
fig. 3). There are also specimens of this species in the Museum collections
labelled Valparaiso ?, Callao, Chili, and Peru.

COLOBOCENTROTUS AND PoDoPHoRA.

The genus Colobocentrotus was established by Brandt in 1835; he also in-
eluded in it Podophora atrata Agass., for which Agassiz in 1840 established the
genus Podophora. With the material at my disposal I have come to the con-
clusion that the original Colobocentrotus of Brandt may be dismembered into
two genera, — the one (Podophora Agass.) to include P. atrata and P. pedifera
(Pls. 7; 20); the other (Colobocentrotus Brandt) limited to Colob. Mertensu
and Colob. Stimpsoni, the former of which was the first species for which
Brandt originally established the genus (Plates 33; 34; 37; 38; and 35; 36).

The species of Colobocentrotus (Plates 33, fig. 3 ; 34, fig. 3; 35, fig. 3; 36,
fiz. 3) are much flatter than those of Podophora. They are at once distin-
guished by the elongated coronal plates which carry a larger number of
primary tubercles uniform in size (arranged in two horizontal rows) in
both the ambulacral and interambulacral zones than in the species of
Podophora. There are as many as twelve vertical rows of interambulacral
tubercles immediately above the ambitus in Colob. Stimpsoni in a specimen
of 65 mm. in diameter; in a specimen of Podophora pedifera of 55 mm.
there are eight, and in a specimen of Podophora atrata of 45 mm. there are
only six vertical rows at the ambitus.

The outline of the test of the species of Colobocentrotus is elliptical or
circular, while it is pentagonal in Podophora. The general shape of the test
of the species of Colobocentrotus and Podophora seems to be fairly constant.
An outline of the ambitus of each of the four species (see figs. a-d p. 5), with
their measurement and number of pores in the ambulacral plates on the
abactinal side, is given for comparison.

Podophora pedifera Agass.
Length, denuded, 55 mm.
Width, denuded, 30 mm.
Height, denuded, 30 mm.
Pairs of pores in each ambulacral plate 11, 12, near the ambitus on the
abactinal side.

4 TROPICAL PACIFIC ECHINI.

Podophora atrata Agass.

Length, denuded, 45 mm.
Width, denuded, 38 mm.
Height, denuded, 18 mm.
Pairs of pores in each ambulacral plate 9, 10, near the ambitus on the
abactinal side.

Colobocentrotus Stimpsoni A. Ag.

Length, denuded, 64 mm.
Width, denuded, 53 mm.
Height, denuded, 24 mm.
Pairs of pores in each ambulacral plate 7, 8, near the ambitus on the
abactinal side.

Colobocentrotus Mertensii Brandt.

Length, denuded, 54 mm.
Width, denuded, 48 mm.
Height, denuded, 22 mm.
Pairs of pores in each ambulacral plate 7, 8, near the ambitus on the

abactinal side.

The outline at the ambitus of Podophora pedifera (Fig. a; Pl. 13, fig. 1)
and of Podophora atrata (Fig. b; Pl. 25, fig. 5) is pentagonal in both; the
actinal side of Podophora pedifera is strongly arched, while that of Podophora
atrata is nearly flat. The ambitus of Colob. Stimpsoni is ellipsoidal (fig. d), in
Colob. Mertensii it is almost circular (fig. c). This dissimilarity can scarcely
be due to age, as the difference in length of the two specimens is only 10 mm.
The number of tubercles in Colob. Mertensii is less than in Colob. Stimpson.
In Mertensii those in the interambulacrum at the ambitus, on the actinal
side, are somewhat larger; hence that side is more concave.

Photography is often misleading when reproducing specimens of natural
size, some parts are apt to be somewhat out of focus. The profiles in Plates
8, fig. 3; 20, fig. 6; 34, fig. 3; and 36, fig. 3, do not fully correspond to the
diagrams (figs. a-d) which are correct.

A comparison of the odd anterior ambulacrum of the two species of Podo-
phora (Pl. 46, figs. 1, 5), and of Colobocentrotus Stimpsoni (Pl. 46, fig. 9)
brings out strikingly their specific differences. In a specimen of Podophora
pedifera Agass. of 55 mm. in diameter the ambitus crosses the fifth and sixth

THE GENUS COLOBOCENTROTUS. 5

plate, and the greatest width of the poriferous field is at the second and third
plate from the actinostome, leaving a comparatively narrow interambulacral field
(Pl. 12, fig. 1). From the ambitus to the abactinal system the large tubercles

Fic. a. P. pedifera. Fic. b. P. atrata.

occupy the whole of the ambulacral plate, leaving room only for a thin line of
small miliaries. The abactinal tubercles alone have a circular scrobicular
area; from the fourth plate from the apex it becomes irregular in outline,

s

Fic. c. Colob. Mertensii. Fic. d. Colob. Stimpsoni.

and the pairs of pores are sometimes pushed in two arcs, or forced out towards
the outer edge of the ambulacral plate. At the ambitus and on the actinal
side the primary tubercles form two short rows on each side of the primary rows
and then extend towards the actinostome as a single row of small secondaries

6 TROPICAL PACIFIC ECHINI.

with a few miliaries on each side of the median line separating the two porif-
erous fields. The difference in appearance of the pores of the actinal edge of
the poriferous field of the region at the ambitus and those of the abactinal side
of the ambulacral system is shown on PI. 46, figs. 2, 3, 4.

The odd anterior ambulacrum of a specimen of Podophora atrata meas-
uring 46 mm. in diameter is at once distinguished from that of Podophora
pedifera by the more regular outline of the vertical rows of primary tuber-
cles. Both the mammary boss and scrobicular area are circular in outline
(Pl. 46, fig. 5); they occupy a smaller are of the ambulacral plates, having a
larger space free from miliaries along the median line of the ambulacral zone.
There are here and there a few small secondary tubercles in the inner angles
of the ambulacral plates.

The vertical rows of primary tubercles extend as small tubercles to the
edge of the actinal system, and numerous minute secondaries and miliaries are
intercalated between the pairs of pores of the poriferous field. This is compar-
atively narrower than that of Podophora pedifera, leaving a much broader
actinal interambulacral zone to sepatate the poriferous fields of adjoining
ambulacra (Pl. 24, fig. 7) than in Podophora pedifera. The change in the
pairs of pores as we pass from the actinal edge to the ambitus and to one
of the abactinal pairs of pores are seen in PI. 46, figs. 6, 7, 8.

In a specimen of Colobocentrotus Stimpsoni measuring 65 mm. in longest
diameter the primary tubercles above the ambitus are of nearly the same
size with a circular mammary boss and scrobicular area (PI. 46, fig. 9), those
at the ambitus being slightly larger and those on the actinal side of the ambi-
tus decidedly larger. In these the mammary boss and the scrobicular area are
somewhat elliptical. The abactinal primary tubercles form above the ambitus
four slightly undulating vertical rows with small miliaries on both sides of
the median line and miliaries between the outer and inner vertical rows.
Below the ambitus there are four irregularly placed large primary tubercles
with a somewhat smaller one, and below that two vertical rows of small, dis-
tant secondaries on each side of the median line extending to the actinal
system, with numerous miliaries and minute secondaries filling the spaces
between the pairs of pores of the poriferous field.

On the abactinal side of the test there are usually three large tubercles on
each plate; near the abactinal system they are reduced to two or to one with
a small secondary. The poriferous arcs occupy the outer part of the
ambulacral plates. There are eight pairs of pores arranged in a very open

e

THE GENUS COLOBOCENTROTUS. ‘i

horse-shoe shape and at the ambitus they are beginning to be crowded out of
place to form the actinal poriferous field. PI. 46, fig. 10 is a pair of pores from
the poriferous field, fig. 11 a pair of pores at the ambitus, and fig. 12 one of
the pores of the twelfth ambulacral plate, counting from the actinal system.

CoLosocentrotus Brandt (A. Ag. emend.)
Colobocentrotus Mertensii, Brandt.

Pls. 2, figs. 8-13 ; 3°, figs. 9-11; 30; 32, figs. 5-8; 35; 36; 39,
figs. 3-4 ; 44; 46, figs. 6-10.

Colobocentrotus Mertensii differs from Colob. Stimpsoni in having a more
circular outline (Pl. 36, figs. 1, 2) and being less depressed (Pl. 36, fig. 3).
It has a proportionally larger actinal system (Pl. 36, fig. 1). The actinal
surface is more sunken than that of Colob. Stimpson. The ambital edge
both of the ambulacral and interambulacral zones carries much larger prim-
ary tubercles (Pl. 36, figs. 1, 3) than those of Colob. Stimpsoni. The actinal
lips are broad; the actinal plates of the interambulacral areas are narrower
than those of Colob. Stimpson’. The actinal interambulacral zone carries four
irregular, vertical rows of most distinct small secondaries larger than in the
corresponding zones of Colob. Stimpsont.

The poriferous fields are broad, slightly sunken ; the median line of the small
distant ambulacral primaries consists of two vertical rows also larger than
those of Colob. Stimpson. The poriferous field is studded with minute miliaries
and small secondaries.

The arrangement of the miliaries on the buccal plates and of the cluster of
narrow crescent-shaped plates of the actinal system (Pl. 36, fig. 1), does not
differ materially from that of Colob. Stimpsoni (Pl. 38, fig. 1). The five pairs
of poriferous buccal plates are somewhat larger in Colob. Stimpsoni than in
Colob. Mertensii. At the ambitus there are two rows of eight large primary
interambulacral tubercles. These rapidly taper to four rows of small tubercles
towards the actinal system; on the abactinal side the primary interambu-
lacral tubercles diminish gradually to the second or third plate from the am-
bitus and then remain of nearly uniform size, diminishing most gradually
towards the abactinal system. At the fourth plate from the apex there are
but six primary tubercles to each interambulacral plate, arranged in two hori-
zontal rows; while nearer the ambitus there are eight or ten similarly arranged.
The intertubercular space is filled with miliaries (Pl. 36, figs. 2, 3).

8 TROPICAL PACIFIC ECHINI.

In the ambulacral zone there are four vertical rows of large primary
tubercles at the ambitus. These gradually diminish in size towards the abac-
tinal system. On each ambulacral plate there are three primary tubercles,
two, one above the other, along the median ambulacral line, the other on the .
distal side of the plate, surrounded by the poriferous arc. This consists of
seven pairs of pores, while there are eight in Colob. Stimpsoni. The intertu-
bercular space is filled with miliaries.

The abactinal system is more raised than in Colob. Stimpsoni, and it is
covered by a coarser tuberculation of small secondaries (Pl. 36, fig. 2). The
anal system is deeply sunken; the genital pores are slightly larger than those
of Colob. Stimpson. There are from ten to twelve closely packed tubercles
on the genital plates, and three on the ocular plates. The madreporic body
occupies the two sides of the distal part of the right anterior genital; the
proximal part adjoining the anal system carries a few small secondaries and
miliaries.

Colobocentrotus Mertensti, when covered with spines (Pl. 35) is of a
darker ash color than Colob. Stimpsoni. The actinal spines of the former,
corresponding to the longer small primary tubercles of that region, are longer
and larger (Pl. 35, fig. 1) than those of Colob. Stimpsoni (Pl. 33, fig. 1), and
the large, flat, truncated radioles are more numerous at the ambitus than in
Colob. Stimpsoni.

In Colob. Mertensii, the primary radioles of the abactinal side of the test
are larger than those of Colob. Stimpsoni (compare PI. 35, figs. 2, 3 with Pl. 33,
fig. 22) and are also more distant, giving a freer circulation of water round
the spines to the miliaries and pedicellarie of the intertubercular areas. The
small radioles covering the abactinal system (Pl. 35, fig. 2) are more pointed
than those of the abactinal system of Colob. Stimpsoni (Pl. 33, fig. 2).

The order of appearance of the vertical rows of primary tubercles of Codd.
Mertensii is shown on Pl. 39, figs. 1, 2, which represent the arrangement of
the radioles (fig. 2) in the right posterior ambulacrum, with the right poste- -
rior interambulacrum and a part of the right anterior ambulacrum. Fig. 2
shows the arrangement of the radioles of the odd posterior interambulacrum,
with the bivium and half of the right posterior ambulacrum.

THE GENUS COLOBOCENTROTUS. 9

Colobocentrotus Stimpsoni A. Ag.

Pls, 2, figs. 4-7 ; 29; 32, figs. 1-4; 33; 34; 37-89, figs. 4-5 ;
40-45, figs. 1-65.

A specimen of Colob. Stimpsoni, measuring 65 mm. when denuded, shows
its elliptical outline (Pls. 34, figs. 1, 2; 38, figs. 1,2). The abactinal system
is slightly raised; the anal system sunken; the poriferous zone is somewhat
sunken, and the genital pores are deeply sunken. The mamelon of the abac-
tinal primary tubercles is glossy, and the general appearance of this species,
when seen from above, is that it is covered with a most uniform tuberculation
diminishing but slightly in size towards the apical system. Immediately at
the ambitus and on both sides of it are placed the horizontal rows of the
largest primary tubercles (Pls. 34, figs. 1, 3; 38, figs. 1,3). A profile view
(Pls. 34, fig. 3; 38, fig. 3) shows the nearly flat actinal side and low, subconi-
eal arched test, A view from the actinal side (Pls. 34, fig. 1; 38, fig. 1)
shows that the actinal surface of the test is flat, the ambital edge being
slightly raised. The poriferous fields are wide, extend to the ambitus, and
are separated by the comparatively narrow interambulacral zone. The two
median vertical rows of small ambulacral tubercles extend to the actinostome.
Two still smaller additional rows of secondary tubercles run across the porif-
erous field about half way between the median line and the outer edge of the
poriferous zone.

Seen from the interior of the test the interambulacral plates show a well
marked groove in the middle of the suture of adjoining plates which is not
shown in the drawings owing to the absence of shading, and the poriferous
zone is raised well above the general level of the remaining part of the
ambulacral plates (Pl. 42, fig. 2).

Owing to the flatness of the test of Colob. Stimpsoni and the sharp angle
made by the ambitus between the abactinal and actinal sides the coronal
plates at the ambitus are greatly compressed and the plates very narrow
(see Pl. 42, fig. 2), this is also seen in the compression of one of the ambulacral
ambital plates (Pl. 42, fig. 7) in which the sutures between the demi-plates
carrying the pairs of pores are practically obliterated. Compare this with an
abactinal plate, the tenth from the actinal system (PI. 42, figs. 5, 6), in which
(fig. 7) the sutures of the demi-plates of the eight pairs of pores are sharply
defined.

In a view of the abactinal part of the ambulacral system, seen from the

10 TROPICAL PACIFIC ECHINI.

interior of the test (Pl. 42, fig. 8, and Pl. 43, fig. 3), it is easy to see the struc-
ture of the upper ambulacral plates. Each plate is made up of a narrow plate
reaching from the median line to the outer edge of the plate and of a
larger plate into which run from the outer edge half way to the median line
seven demi-plates carrying seven pairs of pores. In the tenth plate from the
actinostome in which the eight pairs of pores are only slightly crowded to one
side (Pl. 42, fig. 5), we see the arrangement of the three large primary
tubercles and the intertubercular space occupied by the miliaries and small
secondaries. A view from the inside of the left posterior ambulacrum shows
the sutures indicating the composite structure of the ambulacral plate
(Pl. 42, fig. 6). In the narrow upper plate the pores marked with a small x
correspond to the upper pair of pores of Pl. 42, fig. 5, also marked with an x
and on the same figure we can trace the suture of the demi-plates of the seven
other pairs of pores forming the poriferous arc which extend half way from
the outer edge towards the median ambulacral sutures.

In an exterior view from the actinal side of the poriferous field of the odd
anterior ambulacrum (Pls. 34, fig. 1; 38, fig. 7; 42, fig. 3) it is impossible
to detect either the sutures of the primary plates or of the demi-plates ; but in
a view from the interior (Pl. 42, fig. 4) the peculiar shape assumed by the
primary actinal ambulacral plates and demi-plates, owing to the crowding and
compressing of the poriferous plates is shown in Plate 42, fig. 4. The
pores marked with x in fig. 4 in the two ambulacral plates correspond to the
pairs of pores similarly marked on Pl. 42, fig. 3. The poriferous field is
marked by the number of miliaries and small secondary tubercles interspersed
between the pairs of pores. (Pl. 42, fig. 3.)

The outline of one of the pairs of poriferous buccal plates of Colob. Stimp-
soni is shown on Pl. 42, fig. 2. They each carry a few miliaries and a num-
ber of small secondaries. The plates are originally elliptical; they abut in
older specimens.

Owing to the thickness of the test the passage for the tubes leading to
the pedicels slants very considerably and distant pairs as seen from the inte-
rior on figs. 4, 6, Pl. 42, are thus brought closely together on the exterior side
of the test figs. 3, 5, Pl. 42.

In figs. 3, 4, 5, 6, of Pl. 42, the two minute crosses indicate the position
of the pairs of pores on the inner and outer faces of the test; figs. 3, 4 on the
actinal part of the poriferous field of the odd anterior ambulacrum and figs.
5, 6 of a pair of pores of the abactinal part of the odd anterior ambulacrum of

THE GENUS COLOBOCENTROTUS. 11

Colobocentrotus Stimpson. These figures show how the distant openings for
the pedicels slant across the thickness of the test to come together and form
the pairs of pores.

On Pl. 41, fig. 1, is given a figure of the left anterior interambulacrum of a
specimen of Colob. Stimpsoni measuring with its spines 88 mm. in diameter
with 14 and 15 coronal plates. At the ambitus on the abactinal side there
are 12 rows of primary tubercles which form disconnected vertical rows ; at the
tenth plate there are but five rows and at the third plate from the apex
only three. The tubercles diminish but slightly in size from the ambitus
towards the abactinal system and the intertubercular space is well filled with
miliaries. Below the ambitus on the actinal side are found the largest of
the primary tubercles forming two horizontal lines, the lower one of which is
the largest, extending across the fifth and sixth plates from the actinal sys-
tem. These tubercles carry the large flattened radioles truncated at the tip
which form the ring of larger radioles round the base of the abactinal part of
the test.

Between the row of large tubercles and the actinal system the interambu-
lacral plates on each side of the poriferous field become much narrower
(Pls. 41, fig. 1; 38, fig. 2; 34, fig. 1). There are only four indistinct verti-
cal rows of small primary tubercles. The rest of the plates is filled with
still smaller primary tubercles and patches of miliaries irregularly arranged.

The actinal lips are short but well marked. The lower part of fig. 1, Pl. 41,
shows the distortion which takes place in the outline of the large primary
tubercles below the ambitus owing to the great compression due to the forma-
tion of: the sharp angle of the test at the ambitus. Fig. 3, Pl. 41, shows one
of the most distorted of the primary tubercles on the fifth plate from the
actinostome, the mammary boss, and the scrobicular area being pushed out of
shape. Fig. 4 shows the same tubercle in profile. Fig. 2, Pl. 41, shows the
more regular primary tubercles of the abactinal part of the test in which
the boss and the scrobicular area are but slightly distorted, the boss and
area being usually circular, Pl. 41, fig. 5. The grouping of the miliaries does
not seem to follow any rule. PI. 41, fig. 6, shows those of one of the plates
near the actinostome of the right posterior ambulacrum.

In a specimen measuring 88 mm. in diameter, including the spines, it is pos-
sible to trace the twelve vertical rows of the primary radioles of the interam-
bulacral areas. In Pl. 39, fig. 3, the dotted lines show the twelve rows of the
right posterior interambulacrum and the four vertical rows of the right poste-

12 TROPICAL PACIFIC ECHINI.

rior ambulacrum. On fig. 4 of the same plate are shown the corresponding
vertical rows of the right anterior ambulacrum and interambulacrum. In
both the interambulacra two of the vertical rows along the median line are
included by the inner and outer rows and do not extend either to the abactinal
or the ambital region.

The abactinal system when denuded shows that the genital plates are
covered with closely packed primary tubercles only slightly smaller than those
of the rest of the abactinal surface of the test above the ambitus. (Pls. 34,
fig. 2; 38, fig. 2; 43, fig. 2.) There are in addition a few miliaries and small
secondaries irregularly scattered between the larger tubercles.

The madreporic genital is much larger than the other genitals ; the madre-
porite occupies the greater of the two sides of the plate. The proximal part
carries two primary tubercles and from four to five smaller ones as well as
a few miliaries. The genital openings are large, slightly sunken ; the lateral
posterior genitals are smaller than the odd posterior genital and the left ante-
rior ones. (PI. 43, fig. 2.)

The genital plates are heptagonal. The left anterior genital carries no less
than sixteen primaries with a few miliaries and a couple of smaller primaries.
(Pl. 41, fig. 7.) The other genitals carry from twelve to fourteen primaries
with a few miliaries and secondaries.

The ocular plates are pentagonal, they carry three primary tubercles with
two or three small miliaries, the ocular pores are very small. The posterior
oculars approach the anal system nearer than the anterior pair or the odd
ocular. (Pl. 43, figs. 2, 3.)

The anal system is irregularly circular and covered with three to four con-
centric rows of irregularly shaped pointed and elliptical plates. (Pl. 43, figs.
2, 3.)

In a specimen of Colob. Mertensii measuring 88 mm., when seen from
above the primary radioles covering the abactinal system are seen to be some-
what smaller than those of the rest of the test (Pls. 33, fig. 2; 37, fig. 2; 43,
fig. 1), with the exception of a few larger triangular and elliptical ones which
bridge over the anal system (Pls. 40, figs. 30-32; 43, fig. 1).

On Plates 33 and 37 are given views of a specimen of Colob. Mertensii,
measuring 88 mm. in diameter. The ambital fringe of large truncated flat-
tened primary spines carried by the larger tubercles on the actinal side of
the ambitus and at the ambitus resemble slightly those of Podophora atrata ;
they are comparatively shorter and narrower (Pls. 33, figs. 1, 2; 37, figs. 1, 2)

THE GENUS COLOBOCENTROTUS. 1g:
than those of that species (Pls. 33, figs. 1-3; 37, figs. 1-3). The primaries of
the abactinal side of the test are much smaller than those of Podophora
and are loosely packed upon the test, leaving considerable open space round
each tubercle. This open space is specially marked on the line separating the
ambulacral from the interambulacral zones (Pls. 33, figs. 2, 3; 37, figs. 2, 3).
The general color of the radioles is of a grayish pink color with a slight
tinge of green on the upper surface of the larger primary ambital radioles.

Seen in profile and from the abactinal side the primary radioles which are
irregularly circular at the tip are seen to diminish very gradually in size above
the ambitus as they reach towards the apical system (Pls. 33, figs. 2, 3; 37,
figs. 2, 3). The large abactinal radioles immediately above the ambitus are
arranged more closely than those more distant from it (Pls. 33, fig. 3; 37,
fig. 3).

Seen from the actinal side (Pls. 33, fig. 1; 37, fig. 1), the actinal membrane
is nearly bare, carrying but few small clusters of miliary spines on the pairs
of poriferous plates and a few minute spines irregularly scattered over it.
(Pls. 33, fig. 1; 37, fig. 1). The actinal side of the test below the ambitus is
covered with slender somewhat club-shaped spines varying but slightly in
shape or size between the actinal system and the actinal side of the ambitus.
The poriferous fields are separated by wide interambulacral zones (Pls. 33,
fig. 1; 37, fig. 1).

The spines of the actinal system close to the teeth are short, club-shaped,
slightly flattened (Pl. 40, fig. 1); those from the buccal membrane are some-
what longer (PI. 40, fig. 2). Half way between the actinal system and the
ambitus the radioles are much stouter and only slightly club-shaped (PI. 40,
figs. 3, 4), as are the smaller spines found on the smaller secondary granules
or larger miliaries (Pl. 40, fig. 5); these spines are all delicately striated with
an ill-defined milled ring.

Below the ambitus we pass suddenly to much larger flattened, angular
radioles, rounded at the tip, with a large base for the muscular attachment
(Pl. 40, figs. 6-8). These spines form a part of the principal subambital
fringe of radioles, the primary radioles of which are figured on Pl. 40,
figs. 9-11; these radioles resemble those of P. pedifera, but are comparatively
shorter and narrower; they are flat on the lower surface, somewhat spathi-
form on the upper surface, and greatly flattened towards the tip of the
radiole, as is shown by a profile view (Pl. 40, figs. 9, 11).

We now come to the larger spines of the abactinal pavement immediately

14 TROPICAL PACIFIC ECHINI.

above the ambitus; they are highly asymmetric, fan-shaped, and polygonal
(Pl. 40, figs. 12-14) ; somewhat more abactinally from the ambitus the polyg-
onal radioles are smaller (Pl. 40, figs. 15-17) ; midway between the ambitus and
the abactinal system the primary radioles of the odd ambulacrum are slightly
smaller than those nearer the ambitus (compare Pl. 40, figs. 18-20, to Pl. 40,
figs. 21-23); nearer the abactinal system the radioles have become still
smaller (Pl. 40, figs. 24, 25; and Pl. 40, figs. 26, 27). Pl. 40, fig. 28, is
one of the miliary spines from the upper extremity of the right posterior
interambulacrum, hidden by the larger primary radioles. Figures of
some of the primary radioles of the anal system are given on Ph 40, figs,
29-32.

Seen from the interior, there is a small triangular plate between the actinal
plates of the odd posterior interambulacrum (PI. 43, fig. 7) and of the right
anterior interambulacrum, which may be the remnant of the primordial plates
of these interambulacra.

Popornora Agass.
Podophora atrata Agass.
Pls. 2, figs. 1-3; 5%, figs. 5-8; 16, figs. 9-14; 17-28; 31, figs. 5-8.

A fine specimen of Podophora atrata, measuring 97 mm. including the
spines, is figured on Pl. 21%. It was collected, with others, by the Hon.
Nicolas Pike, at Mauritius. When seen from above, it is of a dark violet,
almost black; seen from the actinal side the marginal spines are of a light
violet color towards the tip, passing to a very light shade of the same color.
The smaller flattened and elongated actinal spines, as well as the miliary spines
of the buccal plates, are of the latter shade; the actinal membrane is chocolate
brown. The larger marginal spines are of a somewhat lighter color on the
upper side, with a tinge of green; the upper surface is also coarsely and
irregularly granular and pitted. On the lower side they are smooth or only
slightly pitted near the tip.

A very interesting specimen of Podophora atrata from Mauritius is figured
on Plate 21%, figs. 1-3. It is marked for the abnormal development of a number
of the ambital radioles. Instead of being merely cylindrical as is the case in
the large majority of the specimens examined they are club-shaped and pro-
portionally larger than the ambital radioles usually are. Their shape reminds
one somewhat of the club-shaped spines of Cidaris Blumenbachit.

THE GENUS COLOBOCENTROTUS. 15

The actinal system of Podophora atrata is pentagonal (Pls. 20, fig. 2;
21, fig. 1). The lips of the gill cuts are short, sharply marked; the proportion
of the actinostome to the test is as 23 to 38. There are five pairs of small
rectangular poriferous plates. The buccal membrane is only covered by a few
round or elliptical plates irregularly scattered and with five clusters of narrow
crescent-shaped plates placed distally next to the pairs of poriferous plates.

In a smaller specimen (PI. 25, fig. 2) the poriferous buccal plates form a
nearly closed ring, the elongated buccal plates are less closely packed than in
older specimens, and the isolated circular plates are more distant.

The changes which take place in the interambulacral zones during the
growth of the test are shown on Pl. 24, figs. 1-4, giving the left anterior
interambulacrum of specimens measuring 8, 14, 26, and 45 mm. in diameter.
In fig. 1, the same as PI. 25, figs. 1-5, there are six and seven interambulacral
plates, each carrying a large or small primary tubercle, with a number of
miliaries or small secondaries along the median line and the outer edge of
the plates.

On Pl. 24, fig. 2, a specimen measuring 14 mm. in diameter, there are
eight and nine interambulacral plates, and a second vertical row of primary
tubercles is forming along the median line of the fourth and fifth plates, as
well as another vertical row of small secondaries on the outer edges of the
third, fourth, fifth, sixth, and the second, third, fourth, fifth plates counting
from the actinostome.

On Pl. 24, fig. 1, these two outer vertical and median rows can be detected
by the greater size of the small secondary on each side of the two primary
rows in the position of the new vertical rows well developed in fig. 2. In
the next stage of the same interambulacrum figured, a specimen measuring
26 mm. in diameter (Pl. 24, fig. 3) with eleven and eleven plates, the four
vertical rows of primary tubercles are well developed. The first rows, so
prominent in figs. 1, 2, are still readily distinguished from the two inner
and the two outer rows by the greater size of the primary tubercles, which
extend from the second to the seventh plate, while the two inner rows extend
the one from the fourth to the eighth plate, the other from the fifth to the
eighth plate.

In the specimen, figured on Pl. 24, fig. 2, the miliaries are proportion-
ally much more numerous than in the younger specimen (PI. 24, fig. 1); they
are quite crowded in the next stage (PI. 24, fig. 3), and in the older specimen,
45 mm. in diameter, they are somewhat more openly arranged (PI. 24, fig. 4).

16 TROPICAL PACIFIC ECHINI.

In this specimen there are twelve and twelve plates; the outer vertical rows
extend from the second to the ninth and perhaps to the tenth plate, the inner
median rows from the fourth to the ninth plate. There still exists a marked
difference in the size of the primaries of the first vertical rows near and at the
ambitus compared to the primary tubercles of the other rows, which, with the
exception of the upper tubercles, are nearly of the same size. It will be
noticed that the outline of the scrobicular areas and of the mammary boss
varies greatly; they are circular, angular, or elliptical according to their posi-
tion in the plate and the amount of space available (see Pl. 24, figs. 5,
7, 8). These changes are due to the great pressure brought about, especially
at the ambitus, by the sudden change of direction in the plates passing from
the abactinal side to the ambitus and to the actinal surface. It will be seen
that in the large specimen (PI. 24, fig. 4) there are on the actinal side four
vertical rows of small secondary tubercles separating the adjoining interam-
bulacral rows (Pl. 24, fig. 4).

The order of appearance of the tubercles of the vertical rows can be
equally well traced in specimens covered with radioles. On Pl. 2, fig. 1, is
seen a young specimen 14 mm. in diameter with the spines having but
two vertical rows of large primary tubercles, as in Pl. 24, fig. 1, andPl. 25,
figs. 3, 4. Pl. 25, fig. 1, shows the pavement of radioles of the five ambula-
cral and interambulacral zones, each with two rows of primary radioles and
the pavement covering the abactinal system. This is shown more in de-
tail on Pl. 22, fig. 1. In fig. 2 of the same plate, in a somewhat larger
individual, we can see the first trace of the spines of the inner vertical row
of tubercles. This is somewhat more advanced in the next largest speci-
men figured, Pl. 22, fig. 3. Ina specimen of 26 mm. the small radioles of
two of the plates of the outer rows can be distinguished; those of the imner
median rows are well seen. In the next stage these radioles have all become
larger and more prominent (Pl. 22, fig. 4). In the following stages, from
specimens measuring 31 mm. to 77 mm. in diameter, the mode of appearance
of the radioles becomes more and more apparent and the vertical lines of
primary tubercles more distinct (Pl. 22, figs. 5-10). In Pl. 22, figs. 5-7, the
distinctness of the outer vertical zones and of the inner median zones becomes
clearer with increasing size, and in the specimens of PI. 22, figs. 8-10, of 67 to
77 mm. in diameter, the dotted lines on the radioles show the course of the
primary vertical row with the dotted lines marking the position of the lateral
and median vertical lines.

THE GENUS COLOBOCENTROTUS. 17

The denuded test of Pl. 24, fig. 4, corresponds nearly to that of Pl. 22, fig.
10, covered with spines; that of Pl. 22, fig. 6, to a stage intermediate between
Pl. 24, figs. 2 and 3.

In a small specimen of Podophora atrata the actinal plates of the odd inter-
ambulacral zone did not show any trace of the primordial plate (Pl. 26, fig. 77).

The passage of the regular poriferous ares into the laterally expanded porif-
erous field on the actinal side of a specimen 45 mm. in diameter is shown on
Pl. 25, fig. 10, where the upper plate is on the abactinal surface and the lower
plate on the actinal side of the test, the former having an are of nine porifer-
ous plates, the other of eleven pairs of pores arranged diagonally across the
outer part of the plate, which is considerably larger than the plate above it
(Pl. 25, fig. 70). The lower poriferous pair is pushed towards the median
ambulacral line.

In a younger specimen of 8 mm. in diameter (PI. 25, fig. 7), taking the same
plates of the odd ambulacral zone partly on the actinal side and partly above
the ambitus, we find on the abactinal side the same arc of nine poriferous plates
arranged round the base of the primary ambulacral tubercle, and on the
actinal side thirteen pairs of pores arranged diagonally across the outer side
of the more elongated actinal ambulacral plates preceding it.

The arrangement of the arcs of poriferous plates on the abactinal side of
the test is seen on Pls. 20, figs. 4, 6; 21, figs. 2, 3; 2, figs. 3, 4, 5, and the
subsequently developed actinal poriferous field on Pls. 20, fig. 2; 21, fig. 1;
25, figs. 2, 6, 9. There are many miliaries in the poriferous field (Pl. 25,
fig. 9) in marked contrast to their absence in P. pedifera.

A figure of P. atrata from the actinal side showing the arrangement of the
poriferous field has been given by Lovén, (Btudes Pl. XVIII, fig. 158).

The arrangement of the abactinal part of the ambulacral system of Podo-
phora atrata is somewhat different from that of P. pedifera. The youngest
plate is at once followed by a plate cut in two by an upper poriferous plate
extending across the ambulacral plate and followed by nine poriferous demi-
plates; these extend from the edge of the interambulacral zone half way to the
median ambulacral line (see Pl. 26, figs. 15, 16).

In an interior view of the abactinal part of the test (PI. 25, fig. 5) the ar-
rangement and number of the ambulacral plates are clearly drawn and the
succession of the large and small ambulacral plates well indicated. In a part
of the odd anterior ambulacrum of a larger specimen, 45 mm. in diameter,

we can follow close to the ambitus the beginning of the widening of the
2

1 TROPICAL PACIFIC ECHINI.

ambulacral plates and the flattening of the smaller intercalated plate (Pl. 26,
fig. 14). In Podophora atrata there are larger miliaries than in P. pedifera
along the median ambulacral line (PI. 21, fig. 3).

In P. atrata the pavement of radioles covering the abactinal system is made

(oa)

up of more irregularly shaped radioles than in. P. pedifera (Pl. 26, figs. 2, 4).
Both the genital and ocular plates are more elongate than those of P. pedi-
fera, and the genital plates carry from two to four small secondaries with a
few small miliaries irregularly scattered. The ocular plates, as in P. pedifera,
also carry one small secondary tubercle, with five to ten small miliaries (PI.
26, fig. 3). In all the species both of Colobocentrotus and Podophora the
ocular plates of the bivium are nearer the anal system than those of the
trivium. The right anterior genital plate is nearly covered by the madrepo-
rite, and carries a few small secondaries along the median line with two or
three clusters of miliaries.

In a smaller specimen (PI. 25, fig. 3) there are few miliaries on the abac-
tinal system (PI. 26, fig. 7), with three to four secondary tubercles of uniform
size on the genitals, and few miliaries. Seen from the interior (Pl. 25, fig. 5)
the sutures of the abactinal system are well shown. The madreporite is a
narrow band extending across the anterior extremity of the right anterior
genital (Pls. 26, fig. 1; 25, fig. 3).

The genital pores are proportionally smaller in P. atrata (Pl. 26, fig. 3)
than in P. pedifera, and are placed as in that species at the very tip of the
genital plates. In the young specimen (PI. 26, fig. 7) there is as yet no trace
of genital pores, but the ocular pores are well developed.

Pl. 26, fig. 5 shows the anal system of a specimen measuring 8 mm. in
diameter (Pl. 26, fig. 2), with eight plates covering the whole anal system.
In a somewhat larger specimen the number of plates has increased, and they
are not as regularly arranged. In a still larger specimen there are two rows
of plates, the outer one being composed of large triangular ones (PI. 26, fig. 7),
and in a specimen of 45 mm. in diameter (Pl. 26, fig. 8) we have a magnified
view of the anal plates of Pl. 26, fig. 3.

The principal types of radioles of Podophora atrata are represented on Pl. 23.

Fig. 1 is a small spine from the actinal membrane near the teeth.

Figs. 2-5 are from the odd ambulacrum and the left anterior interambula-
crum near the actinal system.

Figs. 6-8 are views of a slightly flattened primary radiole from the left
posterior interambulacrum from the actinal side of the ambitus.

THE GENUS COLOBOCENTROTUS. 19

Figs. 9-11 are drawings of the characteristic stout elliptical radioles of
P. atrata, rounded or slightly pointed at the extremity, taken from the
ambitus where they form a ring at the base of the pavement of polygonal
radioles extending from the abactinal side of the ambitus to the apex. The
ambital radioles are from 15 to 20 mm. in length, and of a dark violet color,
almost black on the upper side; on the actinal side the color of the spines
is yellowish or light brown. These large radioles are finely striated, of a
dark violet, with a well-marked milled ring. Blainville writes “d’un violet
fongé presque noir.”

Figs. 12-14 are views of short triangular radioles from the ambitus which
form a part of the abactinal polygonal pavement of the test; they are taken
from the left posterior interambulacrum.

Figs. 15-17, views of a somewhat mushroom-shaped hexagonal or polygonal
radiole taken from the abactinal side of the ambitus, from the right posterior
ambulacrum.

Figs. 18-20 and figs. 21-23 are polygonal radioles taken from the right
anterior interambulacrum from the abactinal side of the ambitus; and figs.
24, 25 is a similar radiole taken from the right posterior interambulacrum.

Figs. 26-28, drawings of a low mushroom-shaped asymmetrical polygonal
radiole taken from half way between the ambitus and the abactinal system.

Figs. 29-31 is an irregularly hexagonal radiole taken from the genital
plates; fig. 32 is a radiole taken from the madreporic genital; and fig. 33
represents a miliary spine hidden by the large pavement of abactinal primary
radioles.

It will be seen on examining the figures of radioles given on Piate 23 that,
with the exception of the spines of the actinal side and of the miliary spines,
all the radioles are asymmetrical.

The striking difference between the radioles of Podophora pedifera and
those of Podophora atrata is well shown on comparing Pl. 11, figs. 11-13;
14-16; 17, 18; 20-21; 22-24; 25-27; 28-30; 31-33 with Plate 23, figs. 7-8; 9-
11; 12-14; 15-17; 18-20; 21-23; 26-28; 29-31. The most marked differences
are in those of the ambital radioles (compare PI. 11, figs. 17-13 with Pl. 23,
figs. 9-11).

Podophora pedifera Agass.
Plates 1; 3°, figs. 1-4; 4-16, figs. 1-8; 31, figs. 1-4.

This species was figured in the Revision of the Echini (PI. IIT, fig. 3),
under the name of Colobocentrotus atratus, and noted as having been collected

20 TROPICAL PACIFIC ECHINI.

at Callao. A number of specimens were collected by the “ Albatross” at
Fakarava on the sea-face of the reef, during the Tropical Pacific Expedition,
1899-1900. An alcoholic specimen in the Museum collection is labelled
Valparaiso? It would seem, therefore, that Podophora pedifera is character-
istic of the Eastern Pacific, extending from Peru and Chili as far as the
Western Paumotus, while the typical Podophora atrata, figured by Blainville,
extends from the Hawaiian Islands to Mauritius, the Seychelles, and Zanzibar.

Seen from above the color of the test is olive green, darkest near the
abactinal system, the pavement of radioles near the ambitus becoming lighter
in color with a purplish tint; the large marginal spines are greenish with an
occasional tinge of purple. Seen from the actinal side the color of the margi-
nal and flattened elongated actinal spines is of a dirty yellow color, the large
marginal radioles being of a light brownish pink at the tip. The actinal
membrane is dark brown.

Podophora pedifera and Podophora atrata are readily distinguished. The
row of primary, flat, truncated radioles which forms a close ring round the
test at the ambitus in P. pedifera (Pls. 7, figs. 1-3 ; 9, figs. 4-6) is in striking
contrast to the corresponding ring of radioles in P. atrata, which consists
of flattened elliptical radioles rounded at the tip and well separated one from
the other (Pl. 20, figs. 1, 3, 5). A comparison of the corresponding figures
of Plates 7, 9, and Plates 20, 21°, 21°, shows this contrast at once. The
abactinal radioles of P. pedifera above the ambitus form a close pavement of
irregularly shaped low radioles closely fitting together, of a prevailing hexagonal
outline, while the corresponding pavement of the low radioles of P. atrata
consists of radioles of a rather rhomboidal or pentagonal outline and less
frequently hexagonal (compare Pls. 20, figs. 3,5; 21, figs. 4-6 with Pls. 7,
figs. 2, 3; 9, figs. 5, 6). The outline of the test is higher, more arched in
P. pedifera (Pls. 7, fig. 3; 8, fig. 3; 9, figs. 3, 6) than in P. atrata, which is
flatter and slightly conical (Pls. 20, figs. 5, 6; 21, figs. 3,6). P. atrata is very
much flatter on the actinal side (Pls. 20, figs. 1, 2, 6; 21, figs. 1, 3, 4) than
P. pedifera in which the actinostome is somewhat sunken (Pls. 8, figs. 1, 3; 9,
figs. 1,3,4). The ambulacral poriferous zone is also proportionally much wider
in P. pedifera (Pls. 8, fig. 1; 9, fig. 1) than in P. atrata (Pls. 20, fig. 2; 21,
fig. 1) where the median rows of tubercles of the ambulacral zone extend far
towards the actinostome (Pls. 20, fig. 2; 21, fig. 2), while in P. pedifera the
corresponding ambulacral tubercles extend but little beyond the ambitus
(Pls. 8, fig. 2; 9, fig. 2). The actinal interambulacral zone is also much broader

THE GENUS COLOBOCENTROTUS. 21

in P. atrata (Pls. 20, fig 2; 21, fig. 2), while it is quite narrow in P. pedifera
(Pls. 8, fig. 1; 9, fig. 2). In the latter there are two rows of small primary
tubercles, while there are four in the former.

Figures 4 of Plates 9 and 21 show how large an area of the actinal surface is
occupied by the closely packed ambulacral suckers, and we can judge of the great
power exerted by these numerous suckers in keeping hold of the rock to which
they are attached even when exposed to the full action of the surf on the outer
beach of a coral reef. The sea has practically no hold on the pavement of
radioles which covers the abactinal side of the test, and thus with the ambu-
lacral suckers a cup is formed which it is difficult to detach from the rocks.

The large and small primary tubercles of P. pedifera are comparatively
larger than those of P. atrata ; the former occupy nearly the whole of the inter-
ambulacral and ambulacral plates leaving but little space for the smaller
secondaries and miliaries, while in P. atrata the tubercles leave quite a part of
the plate bare which carries a few miliaries and small secondary tubercles, and
is covered by an indistinct granulation. In both these species the tubercles
are most prominent, very glossy as if they were rounded beads made of wax
(Pls. 8, 20, figs. 4, 6).

The tubercles diminish somewhat in size from the ambitus towards the
abactinal system (Pls. 8, fig. 3; 9, fig. 3; 20, fig. 6; 21, fig. 3) which is covered
by small secondary tubercles, with the exception of the anal system; but even
that is completely hidden by the pavement of secondary radioles on the geni-
tal plates which lap over the anal system and conceal it (Pls. 7, fig. 2; 20,
fig. 3, and Pls. 9, fig. 5; 21, fig. 5). The genitals carry a few miliaries,
In both these species the anal system is covered with two or three irregularly
concentric rows of small triangular plates (Pls. 9, fig. 2; 21, fig. 2). Accord-
ing to the size of the specimens there are in P. pedifera from six to eight large
tubercles at the ambitus in the interambulacral areas forming six to eight
vertical rows, of which only two extend to the actinal system. There are
but two vertical rows of primary tubercles in the ambulacral zones (Pl. 9,
fig. 3), with a few small miliaries along the median line. Towards the ab-
actinal system a few small secondary tubercles occupy a part of the outer
edges of the interambulacral plates. On the actinal side towards the actino-
stome the primary tubercles of the ambitus are soon replaced by small
secondaries both in the ambulacral and interambulacral areas (Pls. 8, figs.
fers wus aiske 1,08. 20, hig: 2. 21s fic. 7).

A comparison of the left anterior interambulacrum of a denuded specimen

22 TROPICAL PACIFIC ECHINI.

of Podophora pedifera measuring 55 mm. in diameter (PI. 12, fig. 7) with the
same interambulacrum of Podophora atrata of a somewhat smaller specimen
(Pl. 24, fig. 4) will show at once the great difference there is in the tuberculation
of the two species of the genus Podophora. Their development results in the
one case (P. pedifera) in a specimen of twelve and thirteen plates to four
vertical rows, and in the other (P. atrata) to three vertical rows on each inter-
ambulacral plate in a specimen of twelve and twelve interambulacral plates.
The narrowness of the actinal part of the interambulacral zone is very marked
as contrasted to P. atrata (Pl. 12, fig. 1),as well as the extension of the lip of
the gill slits to the fourth plate from the actinostome separating the two outer
vertical zones from the inner ones. The difference in outline of the scrobic-
ular areas and the mammary boss of this species (Pl. 12, figs. 2-6) is as marked
as in P. atrata. There are fewer miliaries than in P. atrata, owing to the
comparatively larger size of the primary tubercles which leave less space
between the scrobicular areas of the primary tubercles for their development.

I have given figures on Plate 10 showing the order of development of the
primary tubercles of some large specimens of P. pedifera measuring from 76
to 87 mm. in diameter (PI. 10, figs. 1-6). We can trace in all the figures the
radioles belonging to the two outer vertical rows, those of the primary row,
and those adjacent to the median line. As will be seen on examining the
figures, the position of the radioles shows the greatest regularity in the growth
of the eight vertical rows of the interambulacral system of P. pedifera just as
they did in the growth of the six vertical rows of the interambulacral zone of
P. atrata. Seen from the interior of the test the plates of the right anterior
interambulacra adjoining the actinal system show what seems to be the ir-
regular remnant of the primordial plate (Pl. 14, fig. 8). Such a plate does
not exist in the odd posterior interambulacrum (Pl. 14, fig. 9).

In a section of P. pedifera (Pl. 13, fig. 1) the outline of the test at the
ambitus is seen to be pentagonal, the point of the pentagon running across
the median line of the odd posterior interambulacrum. The pentagon of the
actinal system runs in the opposite direction. The gradual narrowing up of
the interambulacral plates at the ambitus is shown from the same figure, as
well as the tufts of miliary spines rising at the base of flattened primary spines
in both the ambulacral and interambulacral areas.

The abactinal part of the ambulacral system consists of simple pairs of
pores, the secondary plates of which extend about two thirds across the pri-
mary plates (Pl. 13, fig. 8). The second plate has eight pairs of pores, the upper

THE GENUS COLOBOCENTROTUS. 23

plate only six; the ambulacral plates are much cut up, there being seven plates
and demi-plates in the length of two plates.

The poriferous arcs extend down toa little above the ambitus (Pls. 8,
figs. 2, 3; 9, figs. 2, 3), where the regular arrangement of the pores begins
to be disturbed and they become crowded laterally, see Pls. 8, fig. 1; 9,
figs. 2, 3. Below the ambitus on the actinal side the pairs of pores are thrown
aside laterally and greatly crowded (Pl. 13, figs. 3, 4), as is shown in Pl. 13,
fig. 3, on the actinal side, and Pl. 13, fig. 4, from the interior of the same
plates. There are but few miliaries in the poriferous field (Pl. 13, fig. 3). The
passage of the regular arcs into the broad poriferous field is well shown for
P. atrata on Pl. 25, figs. 6-10. The apical system and the arrangement of
the pores of the abactinal part of the ambulacral system of a large speci-
men measuring 82 mm. is seen on PI. 14, fig. 4. In the second plate from the
apex the upper demi-plate is followed by a row of seven poriferous plates which
extend across the plate towards the median line, and beyond the projection
of the large plate and its last pair of pores. When we come to the fifth
ambulacral plate, counting from the actinal system, there are eleven pairs of
pores arranged in a huge arc round the base of the primary tubercle. The
upper pair is pushed out laterally well toward the median line (PI. 13, fig. 6).
The corresponding ambulacral plates seen from the interior (Pl. 13, fig. 7) are
seen to be made up of a large plate and a narrow, elongated, and smaller plate,
the large plate having nine intercalated poriferous demi-plates extending about
two thirds across it from the side of the interambulacrum; the small plate
having two intercalated poriferous plates. The inner line of sutures of the
intercalated poriferous plates forms a slightly zigzag-shaped vertical line
more or less parallel to the median ambulacral line.

In P. pedifera the actinal system is proportionally larger (Pls. 8,
fig. 1; 9, fig. 2) than in P. atrata. The ratio of the actinostome to the test
is as 28 to 46. The pairs of poriferous actinal plates are elliptical and larger
than in P. atrata; they are more distant from the teeth and are fairly covered
with secondaries and miliaries. The buccal membrane is nearly covered with a
belt of crescent-shaped plates somewhat more closely packed distally from
the five pairs of poriferous plates (Pl. 13, fig. 2). Between the teeth and
the buccal poriferous plates there is a ring of small elliptical plates (Pls. 7,
fig. 1; 8, fig. 1; 9, figs. 1, 4; 13, fig. 2).

The thin folds of the actinal cuts extend almost to the ambitus, enclos-
ing in a sort of furrow the two rows of small secondary interambulacral

24 TROPICAL PACIFIC ECHINI.

tubercles which extend to the actinostome (Pls. 8, fig. 1; 9, fig. 1; 12,
fig. 1).

In the abactinal system of P. pedifera the genital plates (Pl. 14,
fig. 3) carry from two to three large secondary tubercles with one to three
very small secondaries or miliaries in the angles of the plates adjoining the
anal system. The genital plates are irregularly heptagonal, the anterior plates
elongate, the posterior broader than long. The ocular plates are pentagonal
with a broad base curved towards the ambulacral system. They carry one
large secondary tubercle, sometimes also a couple of miliaries, and have a
well-marked ocular pore.

The madreporic genital is elongate, carries three large secondary tubercles,
one in the centre of the plate, the others near the anal system, with five to
six small secondaries. The madreporite occupies the greater part of the geni-
tal. Seen from above, covered with radioles, the abactinal system (PI. 14,
fig. 1) forms a close pavement of irregular pentagonal plates which completely
hide the anal system.

The genital pores are large. They occupy the distal points of the genital
plates. They are well seen on Pl. 14, fig. 4, an interior view of the abactinal
system. This figure also shows the simple arrangement of the abactinal
pairs of pores above the few intercalated demi-plates. The anal system is cir-
cular, covered with three to four rows of small, irregular, elliptical plates.

There is a great contrast between the genital plates of P. pedifera (Pl. 14,
fig. 3) with its three large secondary tubercles closely wedged together, and the
genital plates of P. atrata with its four distant, large secondary tubercles
(Pls. 25, fig. 8; 26, figs. 1, 3).

On Plate 11 has been figured a series of spines of a specimen measuring
82 mm. in diameter selected to represent the great difference and varia-
tion among the primary radioles of the ambital and abactinal part of the test
as well as of the spines of the actinal region and of the miliary spines
hidden by the pavement of primary radioles of the abactinal system (Pls. 11,
fig. 1; 46-48). Figure 1 also shows the great development of the power-
ful muscular system which holds the radioles in place upon their corresponding
primary tubercles. Figures 2-10 of Plate 11 show the shape of the radioles of
the plates of the buccal membrane of the actinal system and of the first plates
of the odd anterior ambulacrum and anterior interambulacrum. These radioles
are all finely striated, somewhat club-shaped, slightly flattened towards the tip,
with an indistinct milled ring and a deep socket at the base of the radioles.

THE GENUS COLOBOCENTROTUS. 25

The ambulacral radioles near the ambitus (Pl. 11, figs. 9, 10), are the first
to show a marked flattening and to approach in outline the large,
flattened, spatula-shaped radioles of the ambital region (PI. 11, figs. 17-13,
14-16). The principal and most characteristic row of primary radioles
(Pl. 11, figs. 11-13) is at the ambitus and it is the one which with the pave-
ment of abactinal primary radioles gives to Colobocentrotus and Podophora
their striking characteristics. These ambital radioles vary in length from
15 to 18 mm; they are olive-green in color.

It is interesting to follow the gradual changes which take place in the
ambital radioles (Pl. 11, figs 17-13) as they are succeeded by the more
abactinal radioles (Pl. 11, figs. 144-16) and gradually form more pavement-
like, hexagonal, somewhat shorter radioles (Pl. 11, figs. 17, 18), to be followed
by still shorter radioles (Pl. 11, figs. 19-21), and then the irregular, short,
mushroom-shaped polygonal or hexagonal radioles (Pl. 11, figs. 22-24; 25-27;
28-30; 31-33), on the thirteenth plate counting from the actinostome. A
series of small, mushroom-shaped radioles has also been selected from the
ocular and genital plates. They continue the abactinal pavement over the
abactinal system (PI. 11, figs. 34-36; 37-39; 40, 41; 42, 43; 44, 45). The color
of the primary radioles is olive green. It will be observed that with the
exception of the radioles of the actinal side and of the miliary spines all
the radioles are asymmetrical.

THE LANTERNS AND AURICLES OF COLOBOCENTROTUS AND PODOPHORA.

Plates 13, figs. 1-4; 14, figs. 5-7; 15; 26, figs. 9-13; 27; 28;
42, figs. 1-4; 43, figs. 4, 5; 44.

The differences in the various parts of the lanterns of Podophora pedifera
and P. atrata are very marked; they are seen in the shape of the compass
(Pls. 15, figs. 13 a b ; 27, figs. 14 a b; 28, figs. 11 a 5), in the proportions of the
corrugations of the sides of the pyramid (Pls. 15, figs. 4, 5, 8, 9 a 6; 27,
figs. 4, 5, 7, 8b; 28, figs. 4, 5, 7 b, 8b); they are much coarser and less
numerous in young specimens (see Pl. 27, figs. 4, 5, 7, 8). The foramen of
the pyramids is longer in P. pedifera than in P. atrata (Pls. 15, figs. 2, 3;
27, 2, 3; 28, figs. 2, 3). The foramen formed by the apophyses and their
hooklike appendages (PI. 15, figs. 3, 4) is much larger than in young specimens
of P. atrata (Pl. 27, figs. 3, 4), where it is rectangular; there are no hooks to
the apophyses (Pl. 27, figs. 7, 8 a) while they are well developed in older speci-

26 TROPICAL PACIFIC ECHINI.

mens (Pl. 28, figs. 3, 4,7 a, 8 a) but do not compare in length with those of
P. pedifera (Pl. 15, figs. 8, 4, 7 a, 9a). The compass is distinctly jointed
in P. pedifera and in the young of P. atrata (Pls. 15, fig. 13; 27, fig. 14); in
the old of atrata there is no trace of any suture. The differences in the braces
are very slight.

In Colobocentrotus Stimpsoni, the pyramids are broader at the summit (PI.
44, figs. 3, 4) than the pyramids of the other species; the corrugations are
coarser (PI. 44, figs. 4, 5, 8 a, 9); the apophysal foramen is wider than that of
P. pedifera, and the hooks are intermediate in length between those of P. pe-
difera and P. atrata. |The compass is jointed (Pl. 44, figs. 12 a, 3).

The auricles of a small specimen of P. atrata, 8 mm. in diameter, are not
united (Pl. 26, figs. 9, 10); they touch in a specimen of 14 mm. (Pl. 26,
fig. 12) and are connected in a specimen of 45 mm. (Pl. 26, fig. 13). Ina
large specimen of P. pedifera 82 mm. in diameter they are closely connected
(Pl. 14, figs. 5, 6); the same is the case in a specimen of Colobocentrotus
Stimpsoni of 88 mm. in diameter (Pl. 43, figs. 4, 5).

The pores close to the actinal system show how the ambulacral plates grad-
ually increase in number and become resorbed as they move into the base of
the auricles both from the actinal and the abactinal sides (see Pls. 14, figs. 5,
6; 26, figs. 12, 13; 43, figs. 4,5; compare also Pl. 26, fig. 9 with Pl. 26, figs. 12,
13). The youngest poriferous plates are still seen on Pl. 14, fig. 6, and Pl. 43,
fig. 4; somewhat older plates are shown on Pl. 14, fig. 7, which have been
resorbed by the auricle (Pls. 14, fig. 5; 26, fig. 13); the upper part of the
auricle in fig. 7, Pl. 14, is cut off.

THE SPICULES OF THE PEDICELS OF COLOBOCENTROTUS AND PODOPHORA.
Pls. 16; 45.

A large number of pedicels of Colobocentrotus and Podophora have been
examined (Pls. 16, 45). They all agreed in having a disk made up of four
basal plates; the periphery of the plates is angularly lobed. The number of
lobes varies from seven to thirteen. In Colobocentrotus Stimpsoni (PI. 45,
figs. 1, 2) the plates have from twelve to thirteen lobes, while in the other
species of the genus, Colob. Mertensii, the basal disks have usually not more
than seven to nine lobes. See the figures of the disk of an actinal pedicel
of P. pedifera (Pl. 16, figs. 1-7), of P. atrata (Pl. 16, figs. 9-11, 13) and of
Colob. Mertensii (Pl. 45, fig. 7). At the base of the basal disk on the lower

THE GENUS COLOBOCENTROTUS. 27

side is found a set of three or four layers of yoke-shaped spicules (Pls. 16, fig.
6; 45, fig. 8). In P. pedifera the yoke-shaped spicules are nearly straight
(Pl. 16, fig. 8), with a row of small perforations on the under side of the
spicule. In P. atrata the yoke-shaped spicule is well arched (PI. 16, fig. 12)
with but few larger perforations.

These perforations frequently pass into more or less prominent teeth (PI.
45, figs. 4, 6). The yoke-shaped spicules of Colob. Stimpsoni (Pl. 45, figs.
3-6) and Mertensii (Pl. 45, figs. 8,9) have fewer perforations than those of
P. pedifera, but more than those of P. atrata. The position of the layers
of the yoke-shaped spicules with reference to the basal disks is well seen in
Pl. 16, figs. 6, 9, 10, and Pl. 45, fig. 8. Fig. 14, Pl. 16, and fig. 10, Pl. 45,
show the atrophied tip of an abactinal pedicel. No spicules were found in
the tubes of the pedicels.

The changes due to growth in the appearance of the basal disk are shown
in figs. 11 and 13, Pl. 16; the former is the basal plate of the pedicel of a de-
nuded specimen of P. atrata measuring 8 mm. in diameter, the other of a
pedicel from a specimen measuring 45 mm. with spines.

The basal disks of the other species were taken from specimens varying
between 70 and 88 mm. in diameter including the spines; P. pedifera, 82 mm. ;
Colob. Mertensii, 70 mm.; Colob. Stimpsoni, 88 mm.

THE PEDICELLARLEZ OF COLOBOCENTROTUS AND PODOPHORA.
Plates 3°; 4-6; 17-19; 29; 30.

The four kinds of pedicellariz of Podophora pedifera are figured on
Pl. 3%, figs. 7-4. The rods vary but little in length, but the length of the
necks differs greatly. In the tridentate pedicellariz (Pl. 3*, fig. 1) the neck
is nearly twice as long as the rod; in the ophicephalous pedicellarie (Pl. 3°,
fig. 2) it is but slightly longer than the rod.

The heads of the triphyllous and globiferous pedicellariz are small (Pl. 3°,
figs. 3, 4), that of the triphyllous pedicellariz being scarcely wider than the
neck; this is about twice the length of the rod (PI. 3, fig. 3), while the neck
of the globiferous pedicellarize is reduced to a minimum, the valves seeming
to rest upon the head of the rod (PI. 3°, fig. 4).

The heads of the tridentate pedicellarie of Podophora atrata seem
to be somewhat more elongated and pointed (Pl. 3%, fig. 5) than those of
P. pedifera, and have a much shorter neck. The ophicephalous pedicellarize

28 TROPICAL PACIFIC ECHINI.

(Pl. 3°, fig. 6) have a comparatively smaller head and longer neck. The
triphyllous pedicellarie (Pl. 3%, fig. 7) are slightly larger, and the globiferous
pedicellarie (Pl. 3°, fig. 8) larger than those of P. pedifera.

The tridentate pedicellarie of Colobocentrotus Mertensii (Pl. 3°, fig. 9)
are closely allied to those of P. atrata, as are also the ophicephalous
ones (Pl. 3%, fig. 12). The triphyllous pedicellariz (Pl. 37, fig. 10) have a
proportionally shorter neck and larger head than in the two species named
above.

In the genus Podophora we find four kinds of pedicellarie: the ophi-
cephalous, tridentate, triphyllous, and globiferous. On Pls. 4-6 I have given
figures of the valves of the four kinds taken from different parts of tests of P.
pedifera. Their position is noted in the description of the Plates. The
figures will give a far better idea of the characteristics of the pedicellariz than
any description I can give. Taking the figures of the valves of ophicephalous
pedicellarie of P. pedifera (Pls. 4, figs. 1-6; 11-17; 6) one cannot
fail to be struck with the asymmetry of the valves, the great variation in
the size and arrangement of the foramina, in that of the hinges, of the serra-
tions of the edges, to say nothing of the great variation in the size of the
ophicephalous pedicellariz which vary from .33 mm. to .61 mm. in length ; we
note such extremes in the shape and the ornamentation of the ophicephalous
pedicellarie of P. pedifera as those of Pl. 6 figs. 1, 2, 4, 9, 10, 12, 14, 16, 17,
taken from four individuals.

The valves of the globiferous pedicellarie of the same species (Pls. 4,
figs. 18-22; 5, figs. 10-13) taken from three specimens show equally great dif-
ferences in shape, size, and ornamentation; they vary from .21 mm. to .37 mm.
in length, and even of the triphyllous pedicellarix figured (Pl. 4, figs. 7-9) no
two of the valves are alike.

We finally come to the tridentate pedicellarie of P. pedifera (Pls. 4,
figs. 7-10; 5, figs. 1-6) varying in length from .86 mm. to .99 mm.
The figures are from pedicellarie taken from five specimens, and they
speak for themselves. No two are alike, either in shape, size, outline, or
ornamentation.

The tridentate pedicellarie of P. atrata, figured on Pls. 18, figs.
1-6, 13-16; 19, figs. 1-13, were taken from three specimens. The valves vary
in length from .41 mm. to .90 mm. The blade of P. atrata is much more
elongate than the blade of P. pedifera. The variation in the serration of the
edge of the blade is very marked (compare Pl. 18, figs. 6, 15, 16 with the same

THE GENUS COLOBOCENTROTUS. 29

edge of Pl. 19, figs. 1, 2, 3, 10, 11). In one case the serration is limited to a
few large teeth, in the other the edge is serrated for the whole length of the
blade. The size and arrangement of the foramina of the valve both of the
basal part and of the blade also varies greatly. In many of the valves
the base passes very gradually into the blade (Pl. 19, figs. 7-10), in others the
junction is sharply marked (PI. 18, figs. 4, 5), and in others the outline of the
base is quite irregular (Pl. 18, figs. 1-3). It would be difficult to say which
of these pedicellariz are typical of P. atrata ; as in P. pedifera the valves of
the triphyllous pedicellarize (Pls. 18, figs. 10-12; 19, figs. 14-16) vary greatly
in outline and in ornamentation. The valves figured were taken from two
specimens; they vary in length from .1]1 mm. to .16 mm.

Compared with the globiferous pedicellarie of P. pedifera, though they
vary greatly (Pls. 4, figs. 18-22 ; 5, figs. 10-13), those of P. atrata (PI. 18, figs.
17, 18) do not show any important differences.

One of the ophicephalous pedicellariz of P. atrata is figured on PI. 18, figs.
7-9. The edge of the valves is more finely serrated than in the majority of
the ophicephalous pedicellarie of P. pedifera, but some of them are fully as
finely serrated as those of P. atrata.

Owing to the great variation in the valves, neither the ophicephalous pedi-
cellariz of Colob. Stimpsoni (Pl. 29, figs. 1-6, 10-13, 16), varying in length
from .36 mm. to .51 mm., nor those of Colob. Mertensii (Pl. 30, figs. 1, 2, 9,
12-15), varying in length from .27 to .48 mm. show any character by
which it would be possible to distinguish these two species, or to dis-
tinguish them in turn from P. pedifera or P. atrata. It is quite possible
to select ophicephalous pedicellarie of P. pedifera and Colob. Stimpsoni
which are very similar, and which it would be difficult to distinguish
(see Pl. 6, fig. 10 and Pl. 29, fig. 13). The valves of the triphyllous
pedicellarize of Colob. Stimpsoni (Pl. 29, figs. 14-15) appear to be somewhat
more slender than those of Colob. Mertensii (Pl. 30, figs. 10-11, 16), and the
foramina of the valves of the triphyllous pedicellarie of these two species are
perhaps, on the whole, smaller than those of P. pedifera and P. atrata.

The tridentate pedicellarize of Colob. Stimpsoni (PI. 29, figs. 7-9) and those
of Colob. Mertensii (Pl. 30, figs. 3-8) resemble more the general pattern of
those of P. pedifera, but in this case also the difference in the ornamentation
of the valves, in the proportions of the base to the blade makes it im-
possible to designate any one figure as a typical tridentate valve of either
species.

30 TROPICAL PACIFIC ECHINI.

The valves of the tridentate pedicellarizxe of Colob. Stimpsoni vary in length
from .78 mm. to .88 mm.; those of Colob. Mertensii from .41 to .81 mm.

Tue CYSTACANTHS AND SPHZRIDIA OF COLOBOCENTROTUS AND PopDOPHORA.
Pls. 1-3; 31; 32.

A comparison of the spheridia of the species of Colobocentrotus and Podo-
phora shows at once how variable they are and how misleading their charac-
ters seem as guides to the affinities of the species of the genus. From a first
glance at the figures of Pls. 31 and 32, we would arrange on one side the more
or less cylindrical spheeridia of P. pedifera (Pl. 31, figs. 1-4), and the three
other species with globular sphzeridia on the other. Yet no one would attempt
to say that P. atrata is more closely allied to Colob. Stimpsoni and Colob.
Mertensti than to P. pedifera, as would be legitimate from the spheridia
alone. ;

P]. 13, fig. 5, shows a line of spheridia on the actinal part of the righ
ambulacral zone. The great variation which exists in the spheridia of P.
atrata is well seen on comparing the figures of spheeridia taken from different
parts of the same individual (measuring 82 mm. in diameter, including the
spines), viz., the left sphzerid of Pl. 31, fig. 1, the left of fig. 2, the middle of
fig. 3, and the right of fig. 4, taken respectively from the right posterior am-
bulacrum, the odd anterior ambulacrum, the left anterior ambulacrum, and the
left posterior ambulacrum. They vary in length from .19 mm. to .34 mm.,
and in outline are cylindrical, elliptical, or club-shaped.

In P. atrata the variation in shape is not as marked (Pl. 31, figs. 5-8),
yet there are- such extremes in shape as the right spherid of Pl. 31,
fig. 6, and the right spherid of Pl. 31, fig. 7, the one measuring .20 mm.,
the other .25 mm. in length; both were taken from the same specimen of
65 mm. in diameter including the spines; the one from the odd anterior ambu-
lacrum, the other from the left posterior ambulacrum.

One might think, on examining the figures of Plate 32, that the spheridia
of Colob. Stimpsoni and Colob. Mertensii differed but little if the comparison is
made between such spheeridia as Pl. 32, figs. 1, 4, and Pl. 32, fig. 7, and the
central figure of fig. 5. When we come to compare such extremes of Colod.
Stimpsoni as Pl. 32, fig. 1, with the extremes of Colob. Mertensii (Pl. 32, fig. 6),
the differences are most striking; while a comparison of the left figure of
Pl. 32, fig. 7 (Colob. Mertensii) with the left figure of Pl. 32, fig. 3 (Colod.

THE GENUS COLOBOCENTROTUS. 31

Stimpsoni) would show that they are specifically identical; again such
spheridia of Colob. Stimpsoni (Pl. 32, fig. 4, right-hand figure) and the third
figure of Pl. 32, fig. 6 (Colob. Mertensii) should leave no doubt of their specific
difference.

The spheridia of Colob. Stimpson’ were taken from the left posterior and
the left anterior ambulacra of a specimen measuring 88 mm. in diameter, and
those of Colob. Mertensii from the odd anterior and the left anterior ambula-
crum of a specimen measuring 77 mm. in diameter including the spines, the
spheridia varying in length from .23 to .27 mm.

The great variation in the shape of the spheridia and of the pedicellarie,
depending in great measure on the position they occupy, does not seem to
make these organs important factors in the ultimate classification of Echini,
as has been maintained by some recent writers. At any rate, in the genera
Colobocentrotus and Podophora we have no basis, from the data obtained by
the examination of the pedicellaria, upon which to build the identification of
the species of this genus. We are led to the belief that while their examina-
tion is certainly most interesting and instructive as far as the general groups
of Echini are concerned, the application of the special details they furnish
can only bring about endless confusion when applied to the classification of
the genera and species of Echini, not only to the exclusion of other characters,
but also when given an inordinate importance in connection with other structural
features of the group.

While examining some specimens of P. pedifera Mr. M. Westergren
observed in the median line of the actinal part of one of the ambulacra pecu-
liar organs, a group of which has been figured on PI. 1, fig. 7. They might
at first sight be taken for clusters of poison glands of some globiferous pedi-
cellarie. These organs are small, the sacs with the spine rarely measuring
more than one millimeter in length. Five or six are found on the actinal side
of each ambulacrum (Pl. 1, fig. 1). They consist in P. pedifera of three spheri-
cal sacs surrounded by an envelope (PI. 1, figs. 3, 4). Each sac has a pore
which in the smaller organs has a more or less pentagonal shape. The larger
sacs seem when expanded to have forced out one or more transparent blad-
ders (Pl. 1, figs. 2-4). I could not detect any spicules or other calcareous de-
posits in any of these diminutive organs which we may call cystacanths.
Only one of the sacs is attached to the extremity of a minute spine, greatly
resembling the rods of pedicellariz.

On PI. 1 are given a number of figures showing the cystacanths of P. pedifera

32 TROPICAL PACIFIC ECHINI.

from different sides. They are drawn from a dried specimen, the sacs having
been treated with alcohol and glycerine. The cystacanths of P. atrata differ
greatly from those of P. pedifera. The sacs are more closely compressed,
forming a club at the top of the rod (Pl. 2, figs. 1-3). The bladders contained '
in the sacs are much thicker than those of P. pedifera. The sacs are also
irregularly dotted with black spots. The cystacanths of P. atrata are found
on the abactinal extremity of the ambulacrum, close to the ocular plates, and
are absent from the actinal side. Pl. 1, figs. 7, 2 are drawn from an alcoholic
specimen.

In Colob. Stimpsoni the cystacanths are comparatively larger (Pl. 2,
figs. 4-7), but coming from a dried specimen they have lost their globular
shape and the existence of pores could not be traced. The sacs seem tougher
than those of P. pedifera. In one of the figures (Pl. 2, fig. 5) a few spicules
could be detected.

The cystacanths of Colob. Mertensii (Pl. 2, figs. 8-12) are elongate, re-
sembling more those of Colob. Stimpsoni. They showed no pores. The spines
of the cystacanths (figs. 11, 12) resemble those of tridentate pedicellarie (Pl.
2, fig. 13) but they expand somewhat more at the tip.

In Chetodiadema pallidum A. Ag. and Clark, eystacanths (Pl. 3) are found
only around the abactinal system, mainly upon the interambulacral plates.
They apparently vary far more in shape than in the species of Colobocentrotus
and Podophora. The cystacanths of Pl. 3, figs. 5, 6, 7,8 are somewhat club
shaped like those of P. atrata. They show well developed pores (PI. 3, figs. 2,
3,5, 7, 11). Others (Pl. 3, fig. 1) look more like the wrinkled sacs of the
cystacanths of Colob. Stimpsoni. Others again consist only of a single
elongated sac (Pl. 3, figs. 2, 9). Transparent bladders like those seen in
P. pedifera are seen on Pl. 3, figs. 1, 2, 11. It will be interesting to see if
cystacanths are found in other echini and to obtain, if possible, some clue
to the function of these problematical organs which suggest affinities both
to the poison glands of globiferous pedicellariz and to the sac-carrying spines
of Echinothuriae.

On Pl. 12, figs. 8-10 of the Ingolf Ex. Echini, Dr. Mortensen gives sections
of an organ which remind one of cystacanths, but he calls them globiferous
pedicellariz, though they seem to be without valves or other calcareous deposits.
He gives no further explanation of their structure in describing the glob-
iferous pedicellaria of Haplos. pellucidum.

Cystacanths vary greatly in number in different specimens, and their occur-

THE GENUS COLOBOCENTROTUS. oo

rence is not limited to the ambulacra near the spheridia, nor are they limited
tothe ambulacra. They are found both in the ambulacral and interambulacral
areas and on the actinal as well as the abactinal sides.

I can only offer suggestions as to the nature of the cystacanths. I have no
observations of any value regarding their function. They may be modified sac-
bearing spines such as are found among the Echinothurize or modified pedi-
cellari# in which the glands have developed into the glands of the cystacanths
at the expense of the valves.

EXPLANATION OF THE PLATES.

paecabs tog? ass
er Leek: Dojolereb 2
mis 1 etait tin Syrta tee ; ar
eleyo 8h) to Ti susie So ofain eii2 3 Sates sy
« 15,0 to tgnoaseyo to elflort &

_ sisty tu07i ange % a
Biite eideconte:o + iteem edb96 who 0° wor aie.
wa? 56 “4 nae ott m
Gd -exte otitis er woe «t wisall axial ft
faissinenses bobcat Vile writ 6A; Tih

vias
7

cigs of? duodtiw

1-11. Cystacanths from a specimen g2 mm. in diameter, including the spines.

1.
2.

3.
4.
5
6.
7.
8.
9
10.

ib
12.

PuaTE 1.

1-12. Podophora pedifera Agass.

Left posterior ambulacrum, actinal side, showing a group of cystacanths.
Expanded cystacanth, 0.92 mm.
Side view, of another specimen, 0.92 mm.

Seen from above; specimen of 0.90 mm.

. Less developed with only three cysts, 0.66 mm.

Another stage with three cysts, 0.60 mm.
Showing the mode of attachment of the cysts to the spine, 0.71 mm.
Profile of eystacanth of 0.54 mm.

. Same, front view.

Side view of one of the smallest eystacanths with three cysts, 0.41 mm.
The same, rear view:

Pedicellaria, to show its comparative size to the eystacanths.

All the figures equally magnified, measurements indicate the natural size
without the spine-

of the sacs

"ALBATROSS TROPICALPAGIFIG Ex 1899-1900. COLOBOCENTROTUS PLATE 1.

SRS Es icad 1S

2a

3

Fai

iis

%

oy,

Aiea

AM.Westergren del B Meisel lith,

qado anige.

ite Vax eee te Er hat tem

oaks geodtiw
eT tae

aw ;
en
7 -

.

PLATE 2.

1-3. Podophora atrata Agass.

1-3. Cystacanths from the abactinal side of a specimen 65 mm. in diameter, including

th
1

e spines.

. From the left posterior ambulacrum, near the ocular plate, front view, 0.37 mm.

2. In the same ambulacrum, but less expanded, 0.39 mm.

3

. Profile, from the same ambulacrum, 0.29 mm.

4-7. Colobocentrotus Stimpsoni A. Ag.

4-7. Cystacanths from a specimen of 88 mm. diameter with spines.

4.

Shows the attachment of the spine to the third lobe, 0.94 mm. from the left anterior
ambulacrun, actinal side.

5. Front view of a cystacanth 0.60 mm. from the right anterior ambulacrum.

on

Same view of a cystacanth 0.58 mm. from the left posterior ambulacrum.
Profile of a cystacanth 0.70 mm. near the ambitus, from the right posterior ambula-

crum.
8-13. Colobocentrotus Mertensii Brandt.

8-13. Cystacanths from a specimen 70 mm. in diameter including spines.

wi

Contracted, with spine, 1.15 mm. close to the ambitus, from the odd anterior ambula-
erum.,

Rear view, 0.44 mm. from the left anterior ambulacrum.

Seen from beneath, 0.59 mm. near the ambitus, from the left anterior ambulacrum.

. Spine of a cystacanth.

Upper end of same, somewhat more magnified.

Spine of a pedicellaria.

All the figures are equally magnified; measurements indicate the natural size of the sacs

thout spine.

COLOBOGENTROTUS PLATE 2.

ALBATROSS TROPICALPACIFIc Ex 1899-1900.

©

Sear EPS
WOR FS S|

B Meisel ith

AM Westergren del

sainiteay: esa asaato Sit
j dni tilt to offie Ldgade Adds? ‘ud iesraeyO .Thek

.

sae Ld ee¢0 eldtol budsorstes Babwomnée & la woty dard, <f
seterb odt Su moist picts are DBL peve oigaia

yy

ofino Ietledstias to diren vit] OA) parworle &

o4 ¢ ‘- ,

7 TG. el Gait) -
or e3.0 hive tataddios ulsiv iiaenaier?

a Puate 3. Reeds 8 eutwhil: , mh
aor oe. peasy isis a -

our HT cl Sit 6) giidt ni fa £ j , 2
ex Sonrer 6 Rota D aj iD-% i 2

zi oe an ama et) saute ayuooY OI

: ava iO yeeon oasek aitin OL 3.0 of xaihuih
eset teva if daooze. bonin, Bo Wiigipd ote! ge iT

19
“pore Noisagsn .SOCT A
at

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Aosanrails ni aera Ustalyaye i te thonie silt baves

PLATES.

1-1l. Chaetodiadema pallidum A. Ag. and Cl.
1-11. Cystacanths, from the abactinal side of the amubulacral and interambulacral plates
round the summit of a specimen 55 mm. in diameter.
1. Front view of a somewhat contracted double cyst, 1 mm.
2. Single cyst, 1.30 mm. magnification of the drawing reduced one half.
3. Expanded, showing the pavement of epithelial cells and the two pores, 0.73 mm.
4. Shows a line of glands, 0.61 mm.
5. Cystacanth with epithelial cells, 0.66 mm.
6. Profile, showing a string of glands, 0.60 mm.
7. Front view with pores, 0.53 mm,
8. Cystacanths similar in form to fig. 7, 0.56 mm.
9. Profile of a cystacanth, 0.73 mm.
10. Younger stage, 0.55 mm.
11. Similar to fig. 10 with large pores, 0.36 mm.
The figures are equally magnified except 2; measurements give the natural size of the
cyst with its spine.
‘* Albatross” Ex. 1902. Station 4104.

"ALBATROSS TROPICALPAGIFIG EX. 1899-1900. COLOBOGENTROTUS PLATE 3.

4 A.M. Westergren del. B Meisel lith.

~~?

i

bol). caliiamn Hs sik tirsy A fratn inane ary
ee” wes 5 “¥ , wie

| * ena te athe weber
tit utglieoihig gtoladoapitgd 4a

: ST ESS a cy fe ober, syoibydsicT

Bastorttesedoiv2 Te
AE Top PUT cata Hei hens & ord +

Sain TS ea boathag edsptahin? a

a ee ae FE arin leaihag nol gclirin® at

a 2 Poneralt wed Jt
Bemus f aia Miva lai, wl lt 2G. dda anes mul odenibsni

“fain 22 2 chat todthen aundidelp 8

was

skrun Ct dbreltwot lang sucladdeoiagd On °

PLATE 3a.

1-4. Podophora pedifera Agass.
From a specimen 74 mm. in diameter, including the spines.
Tridentate pedicellaria. 3.9 mm.
Ophicephalous pedicellaria. 2.9 mm.
Triphyllous pedicellaria. 2.2 mm.

a CS ie

Globiferous pedicellaria. 1.4 mm.

6-8. Podophora atrata Agass.

From a specimen 68 mm. in diameter, including the spines.

5. Tridentate pedicellaria, 2.1 mm.
6. Ophicephalous pedicellaria, 1.5 mm.
7. Triphyllous pedicellaria. 1.2 mm.
8. Globiferous pedicellaria. 1.4 mm.

9-11. Colobocentrotus Mertensii Brandt.

From a specimen 72 mm, in diameter, including the spines.

9. Tridentate pedicellaria. 2.7 mm.
10. Ophicephalous pedicellaria, 1.9 mm.
11. Triphyllous pedicellaria, 2.7 mm.
All the figures are of relative sizes and under the same enlargement; the measurements
indicate the greatest length of the pedicellariz in the positions in which they are drawn.

Gel

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AM Westereren

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PLATE 4.

1-22. Podophora pedifera Agass.

1-22. Valves of Pedicellariz.

~

11.

Valve of an Ophicephalous pedicellaria, in profile, from the buccal membrane near the
teeth.

Valve of an Ophicephalous pedicellaria, another view of the same (fig. 1).
Valve of an Ophicephalous pedicellaria, interior of a valve of the same.
Valve of an Ophicephalous pedicellaria, similar to 3; exterior view.
Valve of an Ophicephalous pedicellaria, interior view of same.

Valve of an Ophicephalous pedicellaria, profile of same.

Valve of an Tridentate pedicellaria, from the right anterior ambulacrum, not far from
the actinal system.

Valve of a Tridentate pedicellaria, the same as 7; external view.
Valve of a Tridentate pedicellaria, the same as 7; internal view.
Valve of a Tridentate pedicellaria, the same as 7; profile of the articulation.

Valve of an Ophicephalous pedicellaria, from the left anterior ambulacrum, nearer the
ambitus than to the actinal system.

12, 13,14. Details of the same pedicellaria as 11; articulations of each valve.
15. Valve of an Ophicephalous pedicellaria, from the left posterior interambulacrum, mid-

16.
17.
18.

way between the actinal system and the ambitus.
Serration from same as 15.
Stalk and head of an Ophicephalous pedicellaria.

Valve of a Globiferous pedicellaria, from the apical part of the left anterior ambu-
lacrum.

Detail of an articulation seen from the exterior, the same as 18.
Interior the same as 18.

. Exterior the same as 18.
. View of the stalk and head of a globiferous pedicellaria.

The figures are about equally enlarged with the exception of 1-6, which are somewhat
larger.

Outer reef, Fakarava, Paumotus, “ Albatross ” Ex., 1899-1900.

LATE 4

COLOBOCENTROTUS PI

TROPICAL PAGIFIG Ex 1899-1900.

"ALBATROSS

B Meisel Jith.

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PuatTe 5.

1-13. Podophora pedifera Agass.
1-13. Valves of Pedicellariw, seen from the exterior.

1. A valve of a Tridentate pedicellaria, 0.86 mm. from the left anterior ambulacrum, near
the actinal system of a specimen 73 mm. in diameter.

2. A valve of a Tridentate pedicellaria, 0.91 mm. from the left anterior ambulacrum, close
to the actinal system of a specimen 75 inm. in diameter.

3. A valve of a Tridentate pedicellaria, 0.94 mm. from the left posterior interambulacrum,
close to the actinal system, from the same specimen as 2.

4. A valve of a Tridentate pedicellaria, 0.98 mm. from the right anterior interambulacrum,
near the actinal system of a specimen 77 mm. in diameter.

5. A valve of a Tridentate pedicellaria, 0.99 mm. from the left anterior ambulacrum, close
to the actinal system of a specimen 80 mm. in diameter.

6. A valve of a Tridentate pedicellaria, 0.94 mm. from the right anterior ambulacrum
midway between the actinal system and the ambitus, from a specimen 82 mm.in
diameter.

7. A valve of a Triphyllous pedicellaria, 0.13 mm. from the right posterior ambulacrum,
at the ambitus, from a specimen 68 mm. in diameter.

8. A valve of a Triphyllous pedicellaria, 0.14 mm. from the odd anterior ambulacrum,
near the actinal system of the same specimen as 7.

9. A valve of a Triphyllous pedicellaria, 0.13 mm. from the left posterior ambulacrum,
midway between the actinal system and the ambitus of the same specimen as T.

10. A valve of a Globiferous pedicellaria, 0.22 mm. from the odd anterior ambulacrum, near
the apical system, from a specimen 72 mm. in diameter.

11. A valve of a Globiferous pedicellaria, 0.37 mm. from the right posterior ambulacrum
near the actinal system of the same specimen as 10.

12. A valve of a Globiferous pedicellaria, 0.22 mm. from the odd anterior ambulacrum,
nearer the ambitus than the abactinal system, from a specimen 74 mm. in diameter.

13. A valve of a Globiferous pedicellaria, 0.21 mm. from the odd anterior ambulacrum, mid-
way between the ambitus and the abactinal system, from a specimen 83 mm. in
diameter.

The measurements of the diameter of the specimens include the spines. The dimensions
given of the pedicellarie are natural size. The corresponding valve was selected for each
figure.

Outer reef, Fakarava, Paumotus, “ Albatross” Ex., 1899-1900.

th

‘ALBATROSS’ TROPICAL PAcIFIC Ex 1899-1900,

COLOBOcENTROTUS PLATE

wae

B Meisel lith

i an ah oe

- iy
2 att
svadgebot 1-5
suldqO tn eavley 26 eweiy torss2R That
Bite SF aii t doe old Seliiop be marte.0 serine : t
mesiit ©} + om waiiie(be Jum 220. evigy oS

SP tigre Gn Gun 26.0 evigg a io

wip od most watt 2E0 svher BE 2
Sah ot sais Bd mes
i? tanst. pre 0 over A 8).
lidme edt bas nineys
wie) am Gb.0-ovipy A 3
jt gh. aediioags amas
uae: aut We arlev AT
; fue Sp eremaiosge &
ion MOF REO aviex & a
ce damiigwepecditse ould
Pate 6. et ti FO eviny A. A
ojid ane ie tye gistete

¢ anos stem: 62.0 sale? as
smoittih wi ~eta: éT

ioe

(2 gtomt ater GM) ving hE
dito yemdi@nte 334 dak
0 do ees) ane 14,0: ovisy A RE
AP eectustinage 6aina
hh » ad m0 sta T6.0 ovloy A. &
198g foes aco TTtemiogges |
notion apa, usier 23.0 ovley Akt
> eretserniG twtr SB
Bes ch agg ocala atid test cisia 3a arly a
Bassa! saga e Ea) idurg od bis ategee >
teog, bbe oat oust ites BRO ovley A Bt
~ as epanivare

ed sort? inet 88.0 ovinw A FE.
BL 2e nesiisece

ad’ tw elnapisienscne alt =

jist BI hui bi &2e22

ia-tia cownyl alt .oxwgit stone

ih AT oe Sod wearer 916

A
a Eis

srt (tsar sHnG

is

1
1
2.
3
4

1,

PLaTE 6.

1-17. Podophora pedifera Agass.

-17. Exterior views of valves of Ophicephalous pedicellarie.

. A valve 0.35 mm. adjoining the teeth, from a specimen 73 mm. in diameter.

A valve 0.44 mm. adjoining the teeth, from a specimen 75 mm. in diameter.

. A valve 0.36 mm. adjoining the teeth, from a specimen 82 mm. in diameter.

. A valve 0.53 mm. from the right posterior ambulacrum, near the ambitus, of a speci-
men 68 mm. in diameter.

A valve 0.59 mm. from the right anterior ambulacrum, midway between the actinal
system and the ambitus of the same specimen as 4.

A valve 0.55 mm. from the left anterior ambulacrum, near the actinal system of the
same specimen as 4.

A valve 0.57 mm. from the right posterior interambulacrum, near the actinal system of
a specimen 72 mm. in diameter.

A valve 0.59 mm. from the left anterior interambulacrum, near the actinal system of
the same specimen as 7.

A valve 0.57 mm. from the right anterior ambulacrum, midway between the actinal
system and the ambitus of a specimen 73 mm. in diameter.

A valve 0.48 mm. from the right anterior ambulacrum, at the ambitus of a specimen
75 mm. in diameter.

. A valve 0.59 mm. from the odd anterior ambulacrum, midway between the actinal system

and the ambitus, of the same specimen as 10.

A valve 0.61 mm. from the odd posterior interambulacrum, near the ambitus, of the
same specimen as 10.

A valve 0.57 mm. from the odd posterior interambulacrum, near the actinal system of
a specimen 77 mm. in diameter.

A valve 0.54 mm. from the left anterior interambulacrum, at the ambitus of a specimen
82 mm. in diameter.

A valve 0.56 mm. from the right posterior ambulacrum, midway between the-actinal
system and the ambitus of a specimen 85 mm. in diameter.

A valve 0.48 mm. from the odd posterior interambulacrum at the ambitus of the same
specimen as 15.

. A valve 0.38 mm. from the left posterior interambulacrum at the ambitus of the same

specimen as 15.

The measurements of the diameter of the test include the spines, with the exception of
2, 4, 5, 6, 14, and 15, which are denuded. The corresponding valve was selected for

each figure. The figures are about equally magnified with the exception of 1-3, which
are somewhat larger. The dimensions given of the valves of the pedicellariz are natural
size.

Outer reef, Fakarava, Paumotus, “ Albatross” Ex., 1899-1900.

"ALBATROSS TROPICALPACIFIGEX 1899-1900.

AM Westergren del *

P ATATt
kag A pele serkreises © 2

_

Lorreitinn soigae b
nm _ ‘
O8 Texiyi to tug sneqir of3 Qo gubire:

- A oF
OOOTBOS Lx " eeoviadik

PLATE 7.

1-3. Podophora pedifera Agass.
1. Seen from the actinal side.
2. The same specimen seen from the abactinal side.
3. The same specimen seen in profile, facing the odd anterior ambulacrum.
The odd anterior ambulacrum occupies the center of the upper part of figures 1 and 2.
All figures are natural size.
Outer reef, Fakarava, Paumotus, “ Albatross” Ex., 1899-1900.

PLaTE 8.
1-3. Podophora pedifera Agass.
Denuded test, seen from the actinal side.

. The same specimen seen from the abactinal side.

The same specimen seen in profile, facing the odd anterior ambulacrum.
All figures are natural size.
The odd anterior ambulacrum occupies the center of the upper part ofefigs. 1, 2.
Outer reef, Fakarava, Paumotus, “ Albatross ” Ex., 1899-1900.

nae ‘ellican a
hie tnutidonds as fos) emake edt (&
‘Gye hbo ous sutond colftoag al bias wa es

SACU CO ROR rs

PLATE 9.
1-6. Podophora pedifera Agass.

Denuded test, seen from the actinal side, measuring 55 mm. in diameter.

The same, from the abactinal side.

The same in profile, facing the odd anterior ambulacrum.

Actinal side of a specimen measuring 82 mm. in diameter, including the spines.

The same specimen seen from the abactinal side.

The same specimen seen facing the odd posterior interambulacrum.
The odd anterior ambulacrum occupies the center of the upper part of figures 1, 2, 4, 5.
Outer reef, Fakarava Paumotus, ‘‘ Albatross” Ex., 1899-1900.

GENTROTUS PLATE 9.

9)
U

COLOB

“ALBATROSS” TROPICGALPAGIFIGEX. 1899-1900

B Meisel lith

AM Westergren del

un Bled ototier (emis silt is Ist
J gist “eeintalth 0 ehtonueT svete

a.

PoP wb

PLATE 10.
1-6. Podophora pedifera Agass.

Odd posterior interambulacrum, and left posterior with part of right posterior ambula-
crum, showing the grouping of the spines of a specimen measuring 75 mm. in diam-
eter, including the spines.

The same portion of the test as in 1 of a specimen, 76 mm. in diameter.

The same portion of the test as in 1 of a specimen 77 mm. in diameter.

The same portion of the test as in 1 of a specimen 80 mm. in diameter.

The same portion of the test as in 1 of a specimen 82 mm. in diameter.

The same portion of the test as in 1 of a specimen 87 mm. in diameter.

The dotted lines unite the primary radioles belonging to the same vertical row.
Outer reef, Fakarava, Paumotus, “ Albatross” Ex., 1899-1900.

=
2
a
9
a
S)
B
LS}
a
3
3
[a
[SI

“ALBATROSS”

doug
a uy
ens) |

¢ Suet ©

it: 4 ee

PuateE 11.

1-48. Podophora pedifera Agass.

1-48, Spines, from a specimen 82 mm. in diameter.

ils

PRPAAMAP wp

e
o

33.

. Spine, top view
. Spine, profile

. Spine, top view

. Spine, upper surface

Spines seen in profile, taken from the left posterior ambulacrum towards the apical
system.
Spine, from a poriferous plate of the buecal membrane.

. Spine, from the first plate at the actinal system of the odd anterior ambulacrum.

Spine, from the second plate, of the left anterior interambulacrum.
Spine, from the third plate, of the left anterior interambulacrum.
Spine, from the third plate, in the odd anterior ambulacrum.

. The profile of the same spine as 6.

. Spine, from the fourth plate of the left anterior ambulacrum.
. Spine, ( upper surface

. Spine, {

11.
. Spine, upper surface > from the fifth plate of the odd anterior ambulacrum.
. Spine, profile these larger radioles vary in length from 15 18 mm.
. Spine, lower surface

5. Spine, upper surface + from the sixth plate of the odd anterior ambulacrum,
. Spine, profile

. Spine, lower surface
. Spine, upper surface

i from the fourth plate of the odd anterior ambulacrum.
lower surface

Spine, lower surface ) at the ambitus.

; from the seventh plate of the odd anterior ambulacrum.

. Spine, profile
. Spine, lower surface

from the tenth plate of the left anterior interambulacrum.

Spine, lower surface
. Spine, upper surface > from the eighth plate of the odd anterior ambulacrum.

. Spine, lower surface
. Spine, top view

from the eleventh plate of the left anterior interambulacrum.

. Spine, profile

. Spine, lower _

from the twelfth plate of the odd anterior ambulacrum.

. Spine, profile
. Spine, lower surface

from the thirteenth plate of the odd anterior ambulacrum.
Spine, profile

The plates from which the spine is taken are counted from the actinal system.

34.

Spine, lower surface

36. Spine, profile

35. Spine, upper or from the ocular and genital plates.

37. Spine, lower surface
38. Spine, upper surface } from the ocular and genital plates.
39. Spine, profile
40. Spine, lower surface ;
Al tie, Garena: ; from the ocular and genital plates.
42. Spine, side view .
“Sie Sess i from the ocular and genital plates.
44, Spine, lower surface
45. Spine, top view
46. Spine,
47. Spine, > spines, hidden by the big radioles, as seen in fig. 1.
48. Spine,

The figures are about equally magnified except 2, 3, 5, 8, and 46, which are enlargements
of adjoining figures in outline. The largest radioles at the ambitus measure 15-18 mm.

i from the ocular and genital plates.

in length.
Outer reef, Fakarava, Paumotus, “ Albatross ” Ex., 1899-1900.

COLOBOCENT

a

‘ALBATROSS TROPICAL PACIFIC Ex. 1899-1900.

iith Ansty Wemer& Winter, Frankturt3M

=|

G

: h
= Waa) whit Vie psdega d igs

-tatigee ec dy on Sa
of eR bbow al bred id Ste
of? 10s? Vadiaa ler Fp quory £ evude)
a wens Aseads ect otelq wows

isl 2 tsders} ivecesient enjaiinbe ie mats Bray A at)
Reeeitten y= Sebo cet 9 ciel sale ese esr tT
wea. aboot Mendes A“ janbbinsy paves dest qt)

a

or

PLATE 12.
1-6. Podophora pedifera Agass.

Left anterior interambulacrum.
The ninth and tenth interabulacral plates from the actinal system.
A tubercle, at the ambitus, from the seventh plate from the actinal system of the left
posterior interambulacrum.
The same tubercle, seen in profile.
Shows a group of miliaries, from the left anterior interambulacrum, abactinal side,
eleventh plate from the actinal system.
A genital plate and adjoining madreporite from the left anterior interambulacrum.
All the figures are taken from a denuded specimen, measuring 55 mm. in diameter.
Outer reef, Fakarava, Paumotus, “ Albatross ” Ex., 1899-1900.

1899-1900

TROPIGAL PaciFic Fx

“ALBATROSS”

bes =
hk On

y 0}; —< o38 <

4 ( > OVO} x

oA . JS a A 7

oS, 0 a 6 bean :
0 O65 <
OBO se Ca e

4Q), S999 ET | OO CN
Reins oe RIS TE a8
\ei >) ‘3 <
SG ) }
‘ g\ SS

ro~
A

} Meisel lith

A.M Westergren del

.
= i} oa
LJ
= we ~ ty :
. os
* oF
t . F -
A uv = = bd
/ } my ae =
; ~~ 0) Eee ap | ;

. . ee
ie

fn .
; | _
=
“7

X
if :
ae
-
"a
' “

€f ares]

- j i .
eb gis EF9N5 3

oJ GN

PuateE 13.

1-8. Podophora pedifera Agass.
Interior view of the actinal side, with the lantern in place, odd ambulacrum at the top.

A pair of poriferous plates of the buccal membrane, facing the odd anterior ambula-
erum.

Exterior view of the odd anterior ambulacrum, at edge of the actinal system.
The same as 3, seen from the interior.
Right posterior ambulacrum, close to the actinal system, showing the spheridia.

Fifth plate from the abactinal system of the odd anterior ambulacrum, abactinal side,
exterior view, showing the arrangement of the pores.

Same as 6, interior view.

Ocular and abactinal ambulacral plates of the left posterior ambulacrum, seen from
the interior.

The figures are from same individual: 82 mm. in diameter, including the spines.
Outer reef, Fakarava, Paumotus, “ Albatross ” Ex., 1899-1900.

i not
ree Ue qerlasgeits miles (eaeig

rat Rest 5 ss) hy Gi Mais ,

; Puate 14. —
i ehatwit go lite Va ‘i Shed ail

| tacsateaksl a1 coos «

War tiyis wid lw atadtses ladies 4) aninteite etale
=> ba = ; - 3
| onhy leibomiag ©
- r;

7 initrdGled lieder vi

wie eddy bi mm OS HUT een logleeibot parse wil)
-

‘
Lan

ae

‘ mol
1/0. a2 ¥ha

+4 oy tet

; aias

t 4a > ‘
iS : ;

Pate 14.

1-9. Podophora pedifera Agass.

_

. Abactinal system covered with spines, of a specimen measuring 81 mm. in diameter.

2. Abactinal system of another specimen, 82 mm. in diameter, denuded of its large
spines.

ow

. Exterior view of the abactinal system, denuded, showing the madreporite, genital pores
and anal system.

The same as 3, seen from the interior.
. Auricles of the left anterior ambulacrum, seen looking towards the actinostome.
Auricles of left anterior ambulacrum, seen from the interior of the test.

Aon PP

. Odd anterior ambulacrum adjoining the actinal system, seen from the interior, the -
auricles having been removed.
8, Interior view of the interradial plates adjoining the actinal system of the right anterior
interambulacrum, showing the primordial plate.
9. The same as 8, of the odd posterior interambulacrum.
Figures 2 to 9 are drawn from the same individual, measuring 82 mm, in diameter,
including the spines.
Outer reef, Fakarava, Paumotus, “ Albatross” Ex., 1899-1900.

COLOBOGENTROTUS PLATE 14

x. 1899-1900

af

IFIc E

TROPIGAL PAGI

LXL| Adlsole
”
2

i

(O)
“©

B Meisel lith

AM Westerpren del

RT De

UL O03 IO 820s 297 no Hota hrren Bis 5 Sense ae
Pri) 2S S08 JAS aging te to bteghecing a
eee
es ey
sesae i WEES (9 fe Dust een AA

rh (Sie Sih ice of Sloun' havco:td qa fe
) oy 1 Sek ee sl tess oe enol ell At
miso; wt cue Ot paris Prowl rib 2 Yamadend)-%)
i entoi 2S «sie sea rhqu se Hott Hasbya ber iid
AIO PAGEL nk cecvtady Ast eet ow rote abs sabe

.
5
—
” .
. = =
5 =
. - a
Om
os y
; Jj
i)
.
‘

Gal Geetrabe do CIs he

PuateE 15.

1-13. Podophora pedifera Agass.

Lantern seen from above.

The same as 1, seen in profile.

One of the pyramids seen from the exterior.

The same as 3, seen from the interior.

The same, seen in profile.

The same, seen from above.

a. Epiphysis of pyramid, seen from the interior, b. pyramid, in profile, seen from the
interior.

Detail of the corrugation on the edge of the inside wall of a pyramid.

a. Epiphysis of pyramid, seen from the exterior, b. pyramid in profile, seen from the
interior.

Upper end of a pyramid, exterior view showing a foramen.

a. Grooved tooth, b. dorsal view, ¢c. seen in profile.

The brace, a. seen from above, b. same in profile, c. from below, d. endwise.

Compass, a. seen from above, b. the same in profile.

All the figures from a specimen measuring 82 mm. in diameter, including the spines.

Outer reef, Fakarava, Paumotus, “ Albatross ” Ex., 1899-1900.

IZ

&

——

=
=
=
—_
—
=S>
—
——
=——
=

A.M. Westergren del

BIT CoG aS) tre

PuaTe 16.

1-8. Podophora pedifera Agass.
The disk of an actinal pedicel, seen from above.
The same, seen from below.
Profile of the same.
Disk of an actinal pedicel, oblique view.
The disk of an actinal pedicel.
Central space of the disk of a pedicel, seen from below with yoke-shaped spicules.
Basal part of one of the lamin.
Spicule.

9-14. Podophora atrata Agass.
An actinal pedicel, seen from below the disk.
Actinal pedicel seen in profile,

. Basal part of one of the lamina of the disk, from a specimen of 8 mm. in diameter.
. Yoke-shaped spicule from the same specimen as 11.

Basal part of one of the laminz of the disk.

. The tip of a dorsal pedicel.

The figures 1 to 8 are from a specimen of 82 mm. in diameter including the spines. With
the exception of 11, 12, the others are drawn from a specimen measuring 74 mm. in diam-
eter, including the spines.

Podophora pedifera from the outside reef, Fakarava, Paumotus, ‘‘ Albatross” Ex.,
1899-1900.

P. atrata from the Hawaiian Ids., A. Garrett Coll.

-
5
.:
)
7
,

——

AM Wesiergren del

1900

B. Meisel lith

1-19. Valves of pedicellarie.

if

|

18.

19.

. A valve 0.22 mm

. A valve 0.32 mm

Puate 17.

1-19. Podophora atrata Agass.

A valve 0.23 mm.) Ophicephalous pedicellaria, from the buccal membrane close to
the teeth. ‘
A valve 0.19 mm. | Ophicephalous pedicellaria, from the buccal membrane close to the
teeth, interior view.
. | Ophicephalous pedicellaria, from the buccal membrane close to the
teeth, exterior view, profile.
A valve 0.22 mm. | Ophicephalous pedicellaria, from the buccal membrane close to the
teeth, detail of articulation, exterior view.
A valve 0.23 mm. | Ophicephalous pedicellaria, from the buccal membrane close to the
teeth, detail of articulation, exterior view.
Valves from the same pedicellaria.
A valve 0.40 mm.) Ophicephalous pedicellaria, from the buccal membrane close to the
teeth, interior view.

A yalve 0.32 mm. | Ophicephalous pedicellaria, from the buccal membrane close to the
teeth, interior view.
A valve 0.40 mm.) Ophicephalous pedicellaria, from the buccal membrane close to the

teeth, exterior view, magnified base of fig. 6.

Ophicephalous pedicellaria, from the buccal membrane close to the

A valve 0.36 mm.
teeth, exterior view, magnified base of fig. T.

Ophicephalous pedicellaria, from the buccal membrane close to the
teeth, exterior view, magnified base of fig. 7.

- Avalve0.47mm. Tridentate pedicellaria, from the actinal side of the left anterior

ambulacrum.

- Avalve0.44mm. Tridentate pedicellaria, interior view from the right anterior am-

bulacrum.

. Avalve 0.47 mm.) Tridentate pedicellaria, exterior view, profile, from the right ante-

rior ambulaerum.

. A valve 0.47 mm. { Tridentate pedicellaria, interior view, profile, from the right ante-

rior ambulacrum.
From the same pedicellaria.

. A-valve 0.26 mm. | Ophicephalous pedicellaria, near the ambitus from the actinal side

of the right posterior interambulacrum.
A valve 0.26mm. | Ophicephalous pedicellaria, serration of edge, same pedicellari1
as 15.

- Avalve 0.24mm. Ophicephalous pedicellaria, interior view from the abactinal side of

the right posterior interambulacrum.

A valve 0.11 mm.) Globiferous pedicellaria, exterior view from the abactinal side of
the left posterior ambulacrum.

A valve 0.11 mm. } Globiferous pedicellaria, profile, same pedicellaria as 18.

Figures 1-5 are the same pedicellaria, from a specimen 8 mm. in diameter; 6-10, from
a specimen 74 mm. in diameter; and 11-19 from a specimen 8 mm. in diameter, including
the spines.

The measurements give the natural size. The enlargement of the figures is about the
same, excepting 6, 7, and 8, 9, 10, which are somewhat larger.

Hawaiian Ids., A. Garrett, Coll.

COLOBOGENTROTUS PLATE 12

ALBATROSS” TROPICAL PAGIFIG EX 1899-1900.

Gwe = eS ee ey sn
SESS 5 STS CSE

Ores

votes

AM. Westerpren del

ae

Mise tcrvseilih 34

Bees ayer

Eee ee fret cb
}

oro 0) pyley a

le
. . 7%
.
pies:
jif “4
ee -)
; le
b 4 jeg!
as Se hd
m4 ;
i ist
UF Les Gaplesit

lbaption

dials seh:

Lic PRBA jh prenaniel

Yn

mere

rhotle

1
4

q

Vata

of

aitellaotbeg to savicV -21-%
3.0 svlay AT

iy tiers:

Jar t

PuatTeE 18.

1-18. Podophora atrata Agass.

1-18. Valves of pedicellarie.

its

bo

17.

18.

A valve 0.67 mm.

A valve 0.65 mm.

A valve 0.63 mm.

A valve 0.85 mm.

A valve 0.88 mm.

A valve 0.87 mm.

A valve 0.57 mm.

A valve 0.50 mm.
A valve 0.48 mm.

. A valve 0.15 mm.

. A valve 0.15 mm.
. A valve 0.16 mm.

A valve 0.49 mm.
A valve 0.47 mm.

A valve 0.48 mm.
A valve 0.39 mm.

A valve 0.24 mm.

A valve 0.21 mm.

cluding the spines.

Tridentate pedicellaria, from the buccal membrane close to the
teeth, exterior view.

Tridentate pedicellaria, from the buccal membrane close to the
teeth, exterior view.

Tridentate pedicellaria, from the buccal membrane close to the
teeth, interior view

Tridentate pedicellaria, from the left anterior ambulacrum, not
far from actinal system, exterior view.

Tridentate pedicellaria, from the left anterior ambulacrum, in-
terior view.

Tridentate pedicellaria, from the left anterior ambulacrunm, in-
terior view profile.

midway between the actinal system and the ambitus, interior
view.
Ophicephalous pedicellaria, same pedicellaria as 7, interior view.
Ophicephalous pedicellaria, same pedicellaria as 7, interior view.
Triphyllous pedicellaria, from the odd anterior ambulacrum
among the spheridia, exterior view.

a pedicellaria from the right anterior ambulacrum 1,
Triphyllous pedicellaria, same pedicellaria as 10, interior view.
Triphyllous pedicellaria, same pedicellaria as 10, exterior view,
profile.

Tridentate pedicellaria, from the actinal side of the left anterior
interambulacrum, near the ambitus, exterior view.

Tridentate pedicellaria, same as 13, interior view.

Tridentate pedicellaria, same as 13, exterior view, profile.
Tridentate pedicellaria, from the right anterior ambulacrum, mid-
way between the ambitus and the abactinal system, interior
view.

Globiferous pedicellaria from the odd anterior ambulacrum near
the ocular plate, interior view.

Globiferous pedicellaria, same as 17, exterior view, profile.

The valves are taken from the same specimen, measuring 74 mm. in diameter, in-

The measurement of the figures gives the natural size ; the enlargement of the valves of

each pedicellaria is the same, but the enlargement of the different pedicellarie is not
identical.
Hawaiian Ids., A. Garrett Coll.

“ALBATROSS” TROPICALPAGIFIGEX 1899-1900.

COLOBOCENTROTUS PLATE 18.

A.M. Westergren del B Meisel lith

-

en arast 2

gf z ae oF Ulf

, on on r - -

Cirallacibog Bisimosbirt wie 66.9 evlav A ot
Sarasa soinetang dc

if eotasbixT a Ts af)

miners vest @rirde
70

mnisaic Warts

ating oii! b gait sat
z nelbthoy secon nage 30 4 pvie
airatne by oui wert, cin aids

‘weIeing ftol oA oy AaosbaT dma a2.0 eves A
7 6 =e ears eran.
edit reds 7 ttm 220 eriay 2

af? cert? -errictre f oe
bbo ead ciott jeutidms oc

baa urseys farting oft weoated awh

S aa odiee tirios feds us
idgis cult coi ,coteys Legitok af) x200 ,niseifvil we Geinsiit «mm F0eviss A oe”
-esgiga tl? gah cli gustenrsib at nat 78 semiooqe 4 30 sunadindine torreinog

ct BBD avice A S

Mist edd croxt .oos es Janitse 90) 30

¢ lentes edd nabywied yawhe

2 ee GO688 ,LiNt

eye
=

: sidaghe en) tage Yetnins odd 42 ye
»

Hier ad

- edt bo agai eal bgynict yank ial ah Bitliseibes otciashi

=e

Pgs saras uneionliliee Govintng st6l edd
wg obi deoitea “edt: ‘Be (eitcliooibor gtnta

; Pea eames avsoelsdes
ae Aitallocih ery od ati

ane tome altng eee gig? som Bitesiar A 3E

pa etd,

z wreck nits SLA 2 es
ie
tint} #44asae2) £ rete =
ee Se Se ae be gee eles heer hie T fae

PuateE 19.

1-16. Podophora atrata Agass.
1-16. Valves of pedicellariz.
1. A valve 0.53 mm. Tridentate pedicellaria, exterior view, near the actinal system,
from the right posterior ambulacrum of a specimen 18 mm. in diameter, including
the spines.
A valve 0.55 mm. Tridentate pedicellaria, near the actinal system, from the left pos-
terior ambulacrum, same specimen as 1.
3. Avalve 0.71 mm. Tridentate pedicellaria, midway between the actinal system and
the ambitus, from the right anterior ambulacrum of a specimen 35 mm. in diameter,
including the spines.
4. A valve 0.66 mm. Tridentate pedicellaria, midway between the actinal system and
the ambitus, from the odd anterior ambulacrum, same specimen as 3.
5. A valve 0.84 mm. Tridentate pedicellaria, at the ambitus, from the left anterior
ambulacrum, same as 3.
6. Avalve 0.83 mm. Tridentate pedicellaria, midway between the actinal system and
the ambitus, from the odd posterior interambulacrum, same as 3.
7. Avalve 0.81 mm. Tridentate pedicellaria, near the actinal system, from the right
posterior ambulacrum of a specimen 67 mm. in diameter, including the spines.
8. A valve 0.85 mm. Tridentate pedicellaria, near the actinal system, from the left
anterior ambulacrum, same specimen as 7.
9. A valve 0.90 mm. Tridentate pedicellaria, midway between the actinal system and
the ambitus, from the left posterior ambulacrum, same as 7.
10. A valve 0.82 mm. Tridentate pedicellaria, at the ambitus, from the right posterior
ambulacrum, same as 7.

. A valve 0.47 mm. Tridentate pedicellaria, midway between the ambitus and the
abactinal system, from the left anterior ambulacrum, same as 7.

. A valve 0.74 mm. Tridentate pedicellaria, on the actinal side of the ambitus, from
the right posterior ambulacrum, same as 7.

. Ayvalve 0.41 mm. Tridentate pedicellaria, near the ocular plate, from the left anterior
ambulacrum, same as 7.

. A valve 0.14 mm. Triphyllous pedicellaria, near the actinal system, from the left
anterior ambulacrum, same as 7.

. Avalve 0.12 mm. Triphyllons pedicellaria, from the abactinal side of the ambitus,
from the right posterior ambulacrum, same as 7.

. A valve 0.11 mm. Triphyllous pedicellaria, near the apical system, from the left
anterior ambulacrum, same as 7.

The same valve in each pedicellaria is figured. The enlargement of the figures is about

the same. All the figures present an exterior view.

Hawaiian Ids., A. Garrett Coll.

AMM

esterpren del

"ALBATROSS TROPICALPAGIFIG Ex 1899-1900

B Meisel lith

&
ag sR ato & Bet - 7

| ¥ ¥ bi ie

ead Te belpasin shies ts

fecidon ‘M07 sta98
nite pa mee ; Daw one ai?
whit Inatinada ads sont mee ‘aise Si!)
o. a hie laationdh ade sant} sane
alt 20 inet olitony Bi Hs

74

a. Bi hystishy “inde eT

,

sig 00 00 dasrnpelad as: wormene fhe oiT

PLATE 20.

1-6. Podophora atrata Agass.
Seen from actinal side.
The same as 1 seen from actinal side denuded of its spines.
The same seen from the abactinal side.
Seen from the abactinal side, denuded of its spines.
Seen in profile facing the odd posterior interambulacrum.
The same denuded, facing the odd anterior ambulacrum.

The odd anterior ambulacrum occupies the center of the upper part of figs. 1, 2, 3,
and 4.

All figures are natural size.
Hawaiian Ids., A. Garrett Coll.

=<

i

3
i

:

ive
‘&
‘+

L-
> 2
re

tm a hy &
Pate 21. Me meee “ae

; 1 bisaresy bibs at
120 wt os esqunne at

—
=f ?

Om wo be op

PuaTE 21.
1-6. Podophora atrata Agass.

Denuded test, seen from the actinal side.

The same seen from the abactinal side.

Seen in profile facing the odd anterior ambulacrum.

Seen from the actinal side. -

The same seen from the abactinal side.

Profile of the same, facing the odd posterior interambulacrum.

All figures are natural size.
The odd anterior ambulacrum occupies the center of the upper part of figures 1, 2, 4, 5.
Hawaiian Ids., A. Garrett coll.

‘ALBATROSS’ TROPICAL PAGIFIC.EX. 1899-1900. GOLOBOCENT

v
fo)
3

AM Westergren del

IN be

w

PLATE 21a.

1-8. Podophora atrata Agass.
Specimen with club-shaped primary radioles, seen from the actinal side.
The same as fig. 1, seen from the abactinal side. ~
The same seen in profile facing the odd posterior interambulacrum.
The odd anterior ambulacrum is at the top of figures 1 and 2.
This specimen measures 92 mm., and was collected at Mauritius.

ENTROTU

ni

LOBOC

Go

bie fenitos sf! not aaa das'T: ne

ibislost incs FY soiuessnt soqusege idk
7 sail

©
al
- * i: s 7
= _
4 =
a _-
o 7 it
| et sd ;
= =“ — O
> ao
-"

iglenisosds ods taut cosa omap ed 2
taf bho sit ying! vitor si comes oT .f

PLaTE 21b.

1-3. Podophora atrata Agass.
Test seen from the actinal side.
The same seen from the abactinal side.

oh pe

The same in profile facing the odd interambulacrum.

This specimen measures 97 mm. including the spines, collected at Mauritius by Nicolas
Pike.

a * staigs fat pb hiieeee ue
a 2 i aeewy BHleat codsieih ii oe BE Romkooye emery
. ; Ba AE NE gob ntra; erates td tan bb ceetiowiss 5 ecu’ |S
= priboleei tateueeih tf oer Sf aniiascn mois -&
sad qusbpioad PONS NI wen BO wnnerie 4 eT
7 aaalye a8) yatholocs Tega Pteettihs Of cra 18 eninge o mort

i
=
i
4
=
Mcuiith UF corn 2h aontinde e ol ®
ui
*

HW geibuloci : eaten #7 Gia BE tominaye ¢ cent *
: ae Se er
P ian ot saitviont aici oD TD simertitesige a sede |
, an

_ yp abe yatta, MORIS ni dees LE gatcivny # eo: #
* atige als wit guitoioet (ateaihib Hi mile TS Moston: ¢ am mind OT

Ps = shee mt wining ods : Five rah ot Io Atwong Yo suben od? wads wig aT
ue aes bhp nat incr ce weitere; Hal ot yeisi che Ateulo

Sotsatwny &6yhs add 40 Med ued fen gibi.
NWO Untisasy gesie ads $o willaitts a) niiijy tail besioh eaiy

63 stare A »@bl osdorelt

4

a4

PLaTE 22.

1-10. Podophora atrata Agass.
From a specimen 12 mm. in diameter, including the spines.
From a specimen 14 mm. in diameter, including the spines.
From a specimen 18 mm. in diameter, including the spines.
From a specimen 26 mm. in diameter, including the spines.
From a specimen 31 mm. in diameter, including the spines.
From a specimen 35 mm. in diameter, including the spines.
From a specimen 46 mm. in diameter, including the spines.
From a specimen 67 mm. in diameter, including the spines.
From a specimen 74 mm. in diameter, including the spines.

Godt ails

ND oe

o %

From a specimen 77 mm. in diameter, including the spines.

The figures show the order of growth of the spines ; the same view is given for each spe-
cimen, showing the left posterior ambulacrum, the odd posterior interambulacrum in the
center, and one half of the right posterior ambulacrum.

The dotted lines join the radioles of the same vertical row.

Hawaiian Ids., A. Garrett Coll.

=
S

COLOBOCENTROTUS PLATE 22.

“ALBATROSS” TROPICAL PaciFic Ex 1899-1900.

B Meisel lith,

AM Westerpren del

a)

ih Sly Ge al
\ w 27 i» Ta)
050 Geet Alle TEAS ia

if Penton ,
' ie hie “ai

Ne | P 2 a Oni

i

aaa reall
p a ha a tral = 5s ee
: «= Kiet Pe
eee ei pure VIVAS Live
; eee ‘Aig ¥
it ee pelea "
- ars: :
» eo Coy oh Me ena ”

nak

PLATE 23.

1-83. Podophora atrata Agass.

1-33 Spines.

ils
2.
3.

2.
10.
ile

Spine, from the actinal system near the teeth.

Spine, near the actinal system, from the odd anterior ambulacrum.

Spine,» lower surface, near the actinal system, from the left anterior interambu-
lacrum.

Spine, } upper surface, near the actinal system, from the left anterior interambu-
lacrum.

Spine,J profile, near the actinal system, from the left anterior interambulacrum.

Spine,» upper surface, from the actinal side of the ambitus, from the left posterior
interambulacrum.

Spine, | lower surface, from the actinal side of the ambitus, from the left posterior
interambulacrum.

Spine, | profile, from the actinal side of the ambitus, from the left posterior inter-
ambulacrum.

Spine, |} upper surface, at the ambitus, from the richt anterior ambulacrum.

Spine, > lower surface, at the ambitus, from the right anterior ambulacrum.

Spine, } profile, at the ambitus, from the right anterior ambulacrum.

These larger radioles vary in length from 15-20 mm.

12.

13.

14.

15.

16.

17.

18.

iS:

20.

21.

22.

23.

Spine, ) upper surface, at the ambitus, from the left posterior interambulacrum.

Spine, ¢ lower surface, at the ambitus, from the left posterior interambulacrum.

Spine, ) profile, at the ambitus, from the left posterior interambulacrum.

Spine, ) lower surface, from the abactinal side, near the ambitus, from the right pos-
terior ambulacrum.

Spine, | top view, from the abactinal side, near the ambitus, from the right posterior

ambulacrum.

Spine, | profile, from the abactinal side, near the ambitus, from the right posterior
ambulacrum.

Spine, ) upper surface, from the abactinal side, near the ambitus, from the right ante-
rior interambulacrum.

Spine, | lower surface, from the abactinal side, near the ambitus, from the right ante-
rior interambulacrum.

Spine, | profile, from the abactinal side, near the ambitus, from the right anterior

interambulacrum.

Spine,) lower surface, from the abactinal side, near the ambitus, from the right ante-
rior interambulacrum.

Spine, | top view, from the abactinal side, near the ambitus, from the right anterior
interambulacrum.

Spine, | profile, from the abactinal side, near the ambitus, from the right anterior
interambulacrum.

24. Spine, side view, from the abactinal side, near the ambitus, from the right posterior
interambulacrum.
25. Spine, | profile, from the abactinal side, near the ambitus, from the right posterior
interambulacrum.
26. Spine, ) lower side, midway between the ambitus and the abactinal side, from the
right posterior interambulacrum.
27. Spine, | profile, midway between the ambitus and the abactinal side, from the right
posterior interambulacrum.
28. Spine, | top view, midway between the ambitus and the abactinal side, from the right
posterior interambulacrum.
29. Spine, ) lower surface, from the genital plates.
30. Spine, > profile, from the genital plates.
31, Spine, } top view, from the genital plates.
32. Spine, side view, from the madreporic plate.
33, Spine, from the abactinal side of the right posterior interambulacrum. These spines
are hidden under the big primary radioles (see Pl. 11, fig. 7).
The enlargement of the figures is about the same. The shaded figs. 7, 2, and 33 are
drawn on a larger scale. ;
Hawaiian Ids., A. Garrett Coll.

"ALBATROSS TROPICAL PACIFIC Ex. 1899-1900. COLOBOCENTROTUS, PLATE 23.

i 6 8

AMWestergren del Lith Ansty WemeraWinter Franke? M

)
:
7 q
> ps
ot Sf
mepineih ot eg Beran #30 aturris ndash suisadue tient Sa” ae ,
Se Poet? LBTUe suite ol Ee
Be atest seucelindoi sie aake ot oS
P hile 5 i Pa 7 " ;
B Mio) cesiwseiusigeorsiin ease ot 7
bis-Je Slonind eutmiy Be
CH ynoeLou Tas Boban :
Slits nislinios sane okt D oar
=

hadeieieis: vent bor ee BAe Tf 7 ; s

Morice 216) wilt ai miseye a—

asisointh acon & - : 7

20 Bastkie ised. ure ior edd Ae *
Rese) oi iitct Set sndas

GD Stared sA-shl esiiswat

“I

PLATE 24.

1-8. Podophora atrata Agass-

_ Left anterior interambulacrum of a denuded specimen measuring 8 mm. in diameter.

The same interambulacrum from a denuded specimen 44 mm. in diameter.

The same interambulacrum from a denuded specimen 26 mm. in diameter.

. The same interambulacrum from a denuded specimen 45 mm. in diameter.

A primary tubercle at the ambitus, on the fifth plate from the actinal system, the de-
nuded test measuring 45 mm. in diameter.

The same, tubercle in profile.

_ The genital and last interambulacral plates, the seventh and eighth from the actinal

system in the left anterior interambulacrum, of a denuded specimen, measuring
8 mm. in diameter.
The ninth and tenth plates of the left anterior interambulacrum, of a denuded test
measuring 45 mm. in diameter.
Hawaiian Ids., A. Garrett Coll.

COLOBOGENTROTUS PLATE 24

"ALBATROSS TROPICALPAGIFIG EX. 1899-1900.

=)

teoedS

08
=

oo.

“0
09, %

B Meisel lith

A.M. Westespren del

BAYH Teitidisc

siiie Dye

Ve

Puate 25.

(2 (nation sngys tevar OT |

cide poiesgan bey a

2 Shahar lapee tt) 0
OU) Hees eink ST tl

> deed aie Who yt

i ade ah Walyspretil 6

Bindsat 4 sorreseciy Atat Ab

‘ouliemdal uri Jo Hatt 2

tre Seprresi6 Bhs GAD Le

rt

te pur sireddid neil

1 aura LS ite reel Git OE

<Opaidira

cog) newest ere 2 of ia,
i) Darth) CA eb E arcing

» Aw. .
¢ 5 aoe)
* wie"s .
mae ap
a a
a” ae =
- SO
ne ee

PLATE 25.
1-10. Podophora atrata Agass.

Seen from abactinal side, with spines, measuring 14 mm. in diameter.
The same, denuded, seen from the actinal side, measuring 8 mm. in diameter.

The same seen from the abactinal side.

Profile of the same, facing the bivium and the odd posterior interambulacrum.
Interior view of the test of the same showing the abactinal system.

Left posterior ambulacral plates adjoining the actinal system.

IP oR wp

Odd anterior ambulacrum at the ambitus.

Part of the abactinal system, the left anterior interambulacral and genital plates.

The odd anterior ambulacral plates adjoining the actinal system, of a denuded speci-
men measuring 45 mm. in diameter.

10. The same ambulacrum, partly on the actinal, and partly on the abactinal side of the

SD feo

ambitus.
Figures 1 to 8 are drawn from the same denuded specimen, measuring 8 mm. in diameter.
Hawaiian Ids., A. Garrett Coll.

COLOBOCGENTROTUS PLATE 25.

“ALBATROSS” TROPICGALPAGIFIC EX. 1899-1900.

B Meisel lith

A.M. Westergren del.

A cw

OS araaT

7 tig. iithw bino-ro9 an megs foriiooih

i om z iLUARLIODEE fo matey? dood

ui byngr Lt Agnes en ty riMtegs Jonk a

B wi stout OF vationga iat exsdeyé lok J

Bi mare cc arauriocgh e30 matiye Tend .

y wwinettin ddgit 612 Je elateam ont D :

=

: | aerial ui sti se coanionys : -
i gerosaoc ‘tye oil waaay yk af ce robsaieg ftel edo exloniua ed? OL
»* “t+ Va 2 .
: : 7 7 g @ ee uemissge
A a tees ad
st Wary selsstal wusoriidataretel qoismacg Bho odd to troy learto?. tf
ae ok

atemeib al
porisTai Sid mo2? sede, pmgponliudace toivatis hie odi to ecitisgA <1

os ; seieaerh oi sco bY nowt
seoteanaily ni sled Sb pains 0 Hate} £E ce adiialodms omeeedt 21
ee Basia att anon wea 1898, mscades gelatin bho sult Io deel 4 :

56 TU Kise ng oe a aletigi a Be bar ziluso sili to wor winizl A!

7 SY atoms Zib a i 2g 2 genie ye & -
a © gaobaadstt 0: } gor? ese 4 wit abt 7

chat Of fase Gi TI pid
. dig). some DA. tstinweli

NAT whe

sO 9

10.

te

16.

PLATE 26.

1-16. Podophora atrata Agass.

Abactinal system, denuded of spines, of a specimen measuring 8 mm. in diameter.

The same, measuring with spines 14 mm. in diameter.

Abactinal system of a specimen measuring with spines 74 mm. in diameter, and
denuded 45 mm.

Abactinal system, covered with spines, of a specimen measuring 77 mm. in diameter.

Anal system of a specimen 8 mm. in diameter.

Anal system of a specimen 14 mm. in diameter.

Anal system of a specimen 26 mm. in diameter.

Anal system of a specimen 45 mm. in diameter.

The auricles of the right anterior ambulacrum, seen from the interior of the test of a
specimen 8 mm. in diameter.

The auricles of the left posterior ambulacrum, looking towards the actinostome, same
specimen as 9.

Actinal part of the odd posterior interambulacrum, interior view of a specimen 8 mm.
in diameter.

Auricles of the odd anterior ambulacrum, seen from the interior of the test of a speci-
men 14 mm. in diameter. :

The same ambulacrum as 12 from a specimen 45 mm. in diameter.

Part of the odd anterior ambulacrum, seen from the interior.

Exterior view of the ocular and ambulacral plates of the left posterior ambulacrum of
a specimen 8 mm. in diameter.

The same seen from the interior.

Figures 1, 5, 9-11, 15 and 16, are drawn from the same individual.
Hawaiian Ids., A. Garrett Coll.

PLATE 26

LOBOCENTROTUS

Co

f
Vv.

TROPICAL PAGIFIG Ex. 1899-1909

ALBATROSS”

9

: pe Sop oo

SD)
=

LG

B. Meise} Jith

Pas
‘
my
eT ee

¥

* 4
ares 8

arods arort 7908 TTT a
eitord ai £598 Pa 28 ona aT mM
Sls mort ross shi: vig att fo a8: &
Ores Hi} ccovk pese Re orgs al ae
Le Oi Oxg avi 998 suse oT 8
= F008 prod “9st oes ORE a
wrotistsi edt most sittorg nt biter oh

mPa? wort biasrg 16 keydgied ae
tons att tie ite :
[ 03 to waiy igeioh xf - faoet ao S700h (By i
. ogtslas 6 OE I Pia fe f ik
- -djoot io Steg aeqqge Gat
BGM WES wf avods igout pose oon SAT cay
mee sili .d jovads on 1592 SEsiEeD Ae AD
Re bebwish 0 sort “ost ete. aeuph eds Fk
Ho a297769 A fehl neuen

17

i

Co) ol EN SAS yD eae

PLATE 27.
1-14. Podophora atrata Agass.

Lantern seen from above.

The same as 1, seen in profile.

One of the pyramids, seen from the exterior.

The same as 3, seen from the interior.

The same seen in profile.

The same seen from above.

Pyramid, in profile, from the interior.

a. Epiphysis of pyramid, from the outside, b. top of a pyramid, in profile.
A tooth still in its socket.

a. Groove of tooth; b. dorsal view of tooth, c. seen in profile.

Part of 10 c. enlarged.

Upper part of tooth.

. a. The brace, seen from above, b. seen in profile, c. from below, d. endwise.
a. Compass seen from above, b. the same in profile.

All the figures are taken from a denuded specimen measuring 8 mm. in diameter.
Hawaiian Ids., A. Garrett Coll.

"ALBATROSS” TROPICALPAGIFIG Ex. 1899-1900. COLOBOGENTROTUS PLATE 2Z

AM etpetr dal
AM Westergren del B Meisel lith

“70h isso iit eas Sede canes we r
elRorq ni mage porns eit 33
- evods: tor} stobe bore@
Phare 28, SIT 37804 bon YH to alsydgigll uk F.

aan rf

of w07? olitong HE move b 7187
; 7 *

sHoTt go58 hiawsiygiay iu if Horsizs oft sont ae to aieysgigd yi 8

to # H ao U
HHS +0 4t te, I
i wy wh tf

SDULGb B PROT Mwah ays eoieyh wet

Mod dew) A abt nals welt

PLATE 28.
1-11. Podophora atrata Agass.

Lantern, seen from above.

The same as 1, seen in profile.

One of the pyramids, seen from the exterior.

The same seen from the interior.

The same seen in profile.

Same seen from above.

a. Epiphysis of pyramid seen from the inside, b. pyramid seen in profile from the

NRarwnde

interior.

a. Epiphysis of pyramid from the exterior, b. upper end of a pyramid seen from the
exterior.
9. a. Groove of tooth, b. dorsal view of tooth, c. seen in profile.

10. a. The brace, seen from above, b. seen in profile, c. from below, d. endwise.

11. a. Compass seen from above, b. the same in profile.

%

The figures are drawn from a denuded specimen 45 mm. in diameter.
Hawaiian Ids., A. Garrett Coll.

COLOBOGENTROTUS PLATE 28.

“ALBATROSS” TROPICALPAGIFIC Ex. 1899-1900.

©

|

Wim

B Meise! lith

AM Westergren del

PuLaTE 29.

1-17. Colobocentrotus Stimpsoni A. Ag.

1-17. Valves of pedicellarie.

wo

13.

14.

15.

16.

17.

A valve 0.41 mm. of an Ophicephalous pedicellaria, exterior view, near the teeth.

A valve 0.36 mm, ) Ophicephalous pedicellaria, interior view, near the teeth.

A valve 0.48 mm. $Ophicephalous pedicellaria, exterior view, nearer the actinal system
than the ambitus, from the odd anterior ambulacrum.

A valve 0.50 mm. Ophicephalous pedicellaria profile, interior view, nearer the actinal
system than the ambitus, from the right anterior ambulacrum.

A valve 0.51 mm. Ophicephalous pedicellaria, interior view.

A valve 0.51 mm. Ophicephalous pedicellaria, midway between the actinal system
and the ambitus, from the left anterior ambulacrum.

A valve 0.88 mm.) Tridentate pedicellaria, exterior view, not far from the actinal
system, from the left posterior ambulacrum.

A valve 0.78 mm. | Tridentate pedicellaria, interior view.

A valve 0.86 mm.) Tridentate pedicellaria, profile, exterior view.

A valve 0.47mm. Ophicephalous pedicellaria, showing the articulation near the am-
bitus, from the left anterior interambulacrum.

. Avalve 0.47mm. Ophicephalous pedicellaria, interior view, nearer the ambitus than

the actinal system, from the right anterior interambulacrum.

. A valve 0.47 mm. Ophicephalous pedicellaria, interior view near the ambitus, from

the right anterior interambulacrum.

A valve 0.36 mm. Ophicephalous pedicellaria, exterior view midway between the
ambitus and the abactinal system, from the right anterior inter-
ambulacrum.

A valve 0.17 mm. Triphyllous pedicellaria, midway between the actinal system and
the ambitus, from the left anterior interambulacrum.

A valve 0.16 mm. Triphyllous pedicellaria, from the same, interior view of a single
valve.

A valve 0.34 mm. Ophicephalous pedicellaria, interior view not far from the ocular
plate, from the left posterior ambulacrum.

A valve 0.9mm. Triphyllous pedicellaria, exterior view close to the ocular plate,
of the right posterior ambulacrum.

The enlargement of the pedicellariew of the actinal system is somewhat greater than that

of figs. 7-9 which are drawn on a smaller scale.

All the figures are from a specimen 88 mm. in diameter including the spines. Collected
by Dr. Wm. Stimpson at the Bonin Ids.

PROPI

BATROSS”

aE

‘A

Ss

Bdcay

CCS,

i
astsitr <b ) | Sriag, A~ -

. :
“— A ~~ -
V9.0 tele TA” he ‘

220.0 svicy KS :

ROMgome ge edt

S22 eB nied

Pate 30.

1-16. Colobocentrotus Mertensii Brandt.

1-16. Valves of pedicellariz.

1. A valve 0.38 mm. ) Ophicephalous pedicellaria, interior view near the teeth.

2. A valve 0.35 mm.) Ophicephalous pedicellaria, exterior view, near the teeth.

3. A valve 0.81 mm. ) Tridentate pedicellaria, exterior view, close to the actinal system
from the odd anterior ambulacrum.

4. A valve 0.78 mm. { Tridentate pedicellaria, interior view of the same pedicellaria as 3.

5. A valve 0.77 mm.) Tridentate pedicellaria, profile, interior view of the same as 3.

6. A valve 0.54 mm. ) Tridentate pedicellaria, exterior view, midway between the ambitus
and the actinal system, from the left posterior ambulacrum.

7. A valve 0.41 mm. { Tridentate pedicellaria, interior view, from the left posterior am-
bulacrum.

8. A valve 0.47 mm. Tridentate pedicellaria, close to the ambitus, from the right an-
terior ambulacrum.

9. A valve 0.48 mm. Ophicephalous pedicellaria, exterior view, close to the ambitus,
from the right anterior ambulacrum.

10, A valve 0.12 mm. ) Triphyllous pedicellaria, exterior view, midway between the actinal
system and the ambitus, from the left anterior ambulacrum.

11. A valve 0.14 mm. J Triphyllous pedicellaria, profile, same pedicellaria as 10.

12. A valve 0.46 mm. ) Ophicephalous pedicellaria, interior view close to the ambitus,
from the right anterior interambulacrum.

13. A valve 0.44 mm. { Ophicephalous pedicellaria, exterior view of same pedicellaria as
12.

14. A valve 0.31 mm. ) Ophicephalous pedicellaria, interior view midway between the am-
bitus and the abactinal system, from the left posterior interam-
bulacrum.

15. A valve 0.27 mm. | Ophicephalous pedicellaria, exterior view of the same pedicellaria
as 14.

16. Avalve 0.9mm. ‘Triphyllous pedicellaria, exterior view, close to the ocular plate,

from the right anterior ambulacrum,

From a specimen measuring 70 mm. in diameter, with spines.

Bonin Ids., N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

"ALBATROSS TROPICAL PACIFIG

°
oO

200
00

00,0006,

(e}
7 OO}
30%

AM Westergren del,

aa d
BAB do pere! ou) Ne ea it tt no £
| east B80 af steet

en ee &

“ira totredas Sia] oilt arow

PSD comes sada isi } ou loduts soins og oe is SH? owt sibivedgs ome &
4 a sar snegl fascowe scit = an Banister tho sds cull 9
meas oS) ! iyi; " 5 40 i ¥ han ont mi biredge a.
b vas LO Bk aoliutcog tol ont moxt 8

ae oe A ee eur ase et euro Meee ;
. _ CEE ee OR ee 2 igang theses

a tts. paid Junoda ci S Bld lo Jucmoyrains ent T

PuaTE 31.
1-4. Podophora pedifera Agass.

1-8. Spheridia.

1. Spheridia, the first measures 0.27 mm. in length, all from the right posterior ambu-
lacrum.

2. From the odd anterior ambulacrum, the longest measures 0.34 mm., the length of its
mate is 0.29 mm.

3. The first figure measures 0.28 mm., the second 0.19 mm., from the left anterior ambu-
lacrum.

4. From the left posterior ambulacrum, the first figure measures 0.26 mm.

6-8. Podophora atrata Agass.

5. Three spheridia from the right posterior ambulacrum, the middle one measures 0.26
mm.
6. From the odd anterior ambulacrum, the second figure measures 0.25 mm.
7. Spheridia from the left anterior ambulacrum, the third figure measures 0.26 mm.
8. From the left posterior ambulacrum, the second figure measures 0.29 mm.
The spheridia of 1-4 are from the same specimen, measuring 85 mm. in diameter, in-
cluding the spines, and those of 5-8 are from an individual measuring 77 mm.
The enlargement of the figures is about the same.

COLOBOGENTROTUS PLATE 31.

ALBATROSS” TROPICAL PACIFIG EX 1899-1900.

.

B Meisel ith

AM, Westergren del.

SE eragu

eA LA soegmaiys BHO OMe. 32

;

aL Estseeect brane ade hts tic

ostsnline wiroteoq adel
pareaet SEI Sits ctovan!
paagtel az sar 720 caren: linget ines. tT £

Pat Thu ady (asali 4 Faseut? Fi ig

” 4 5
TH QO Ut? at se 2HGS SB

ref bags.

B2rscunicd - 4-4

ein ia ISshog dlfix eld arin) Abiwraicebandy &
m j pags ni
eeeesit o5t cit Téstediah Bomaton Feo po seg ae

- Ate th, wiro Ghrupd 445

and yoniave!cdas Wires ‘ef 60) o7t GSihimedys JF
a . +HPsast
‘Loe del.6A2 fexrmacdiodare 4 Heed Zid adi word 36
Redo qS suitor 443 oxent win dt 40 diliznetie of
petwieron: levbiviiet as mort Bl 20 veod) bas seniga
ae ot? inode ¢i seuryd ols 26 Sovmmyreles oT
Move aie tN AO xB 2A DM , cht olaoek

wis IGitas bho edt ny 72s

at

PLaTE 32.
1-4. Colobocentrotus Stimpsoni A. Ag.
1-8. Spheridia.
1. Spheridia, the second measures 0.25 mm. in length; all the spheridia are from the
right posterior ambulacrum.
2. From the odd anterior ambulacrum, the first measures 0.26 mm. in length.
The second figure measures 0.27 mm. in length; from the left anterior ambulacrum. ~

4. From the left posterior ambulacrum, the first figure measures 0.22 mm. in length, the
second 0.27 mm.

~

5-8. Colobocentrotus Mertensii Brandt.

5. Three spheridia from the right posterior ambulacrum, the last one measuring 0.26 mm.
in length.
6. From the odd anterior ambulacrum, the first figure measures 0.27 mm. in length and
the fourth one 0.23 mm.
7. Spheridia from the left anterior ambulacrum, the second figure measures 0.25 mm. in
length.
8. From the left posterior ambulacrum, the first figure measures 0.28 mm. in length.
The sphzridia of 1-4 are from the same specimen, 88 mm. in diameter, including the
spines and those of 5-8 from an individual measuring 70 mm,
The enlargement of the figures is about the same.
Bonin Ids., N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

“ALBATROSS” TROPICAL

:
£

PAciFIc Ex 1899-1900.

“

COLOBOGENTROTUS PLATE 32

BINOEdS ad? 1023 ooR

SB UCEIOSHE Binks oft
(Uims woissnr bho say .
foutian ee gong IFA
Heel ered) eet inet

fants oft quit nase t
=
“‘feroclidans toretam |
BIsirg Lo treq TOY Ooh

eT? WT OY)

iy

PLATE 33.
1-3. Colobocentrotus Stimpsoni A. Ag.

1. Seen from the actinal side.

2. Seen from the abactinal side.

3. The same specimen, seen in profile, facing the odd anterior ambulacrum.

, The odd anterior ambulacrum occupies the center of the upper part of figures 1, 2.
All figures are natural size.
Bonin Ids., Captains Ringgold and Rodgers, N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

a4 ;
are 8a

et

\ ates

ov) we eee

hie Leaiton »d9 incr} want 1.

BabMA sion ol cone somtowre amas alt

fhe galt

weaigs ail to bebenets ;
TE
ane ade soetny
MD snags a ST 2d oT el

PLaTE 34.
1-8. Colobocentrotus Stimpsoni A. Ag.

1. Seen from the actinal side; denuded of its spines.
2. The same seen from the abactinal side.
3. The same specimen, seen in profile, facing the odd anterior ambulacrum.
All figures are natural size.
Bonin Ids., Captains Ringgold and Rodgers, N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

PLATE 35.
1-3. Colobocentrotus Mertensii Brandt.

1, Seen from the actinal side.

2. Seen from the abactinal side.

3. The same specimen, seen in profile, facing the odd anterior ambulacrum.
All figures are natural size.
The odd anterior ambulacrum occupies the center of the upper part of figs. 1, 2.
Bonin Ids., Captains Ringgold and Rodgers, N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

8-5
hee
7

obia Leniion odt moi nest .t

; bis fantiomdia adi inost noon corm dT Sf

Ce tm etd WB aie oo L
smpsoalisd

; ota evry ITA

fit consi VP tt th at AEM | abl ciao

a

PuatTE 36.
1-3. Colobocentrotus Mertensii Brandt.

1. Seen from the actinal side.
2. The same seen from the abactinal side. -
3. The same specimen, seen in profile, facing the bivium and odd posterior interam-
bulacrum.
All figures are natural size.
Bonin Ids., Captains Ringgold and Rodgers, N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

4p

rie ii

pinata ete viii ellb seat onal il
‘Bia Lnucisabe wil! iw abeg doses IT
sien IMAE is ca ceaeetio £

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J 28 eT AMA pe Meet sot abil niwot

~ Sins
7 we >
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2 ~
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re Da 2
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=
ae ee
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?

PLATE 37.

1-8. Colobocentrotus Stimpsoni A. Ag.

1. Seen from the actinal side, measuring 88 mm. in diameter including the spines.
2. The same seen from the abactinal side.
3. Profile of the same facing the odd anterior ambulacrum.
All figures are natural size.
Bonin Ids., Captains Ringgold and Rodgers, N. P. Ex. Ex., Dr. Wm. Stimpson Coll,

GOLOBOGENTROTUS PLATE 37

1899-1900.

IFIG 2X

.

TROPICAL PA

.

ROSS

er

Pe

B Meisel lith

A.M Westergren de)

ale ee

aac

* aL aAG petra git.

‘ ha jaa yi Hibelg 4

eta eight IDK,
bt anata

es

PLATE 38.

1-38. Colobocentrotus Simpson) A. Ag

its spines, measuring 65 mm. in diameter.

2. The same seen from the abactinal side.
3. Profile of the same, facing the odd anterior anibslasrait
All Beuree are WEEE size.

COLOBOGENTROTUS PLATE 38.

ALBATROSS TROPICAL PAGIFIG EX: 1899-1900.

v

B Meise! lith.

mn. del

AM West

PuaTE 39.
1-2. Colobocentrotus Mertensii Brandt.

1. Showing the right posterior ambulacrum, with the right posterior interambulacrum,
and a part of the right anterior ambulacrum.

2. Showing the odd posterior interambulacrum with the bivium, and half of the right
posterior ambulacrum.

3-4. Colobocentrotus Stimpsoni A. Ag.

3. The right posterior interambulacrum, with the right posterior ambulacrum and a part
of the right anterior ambulacrum.

4. The right anterior interambulacrum, with the right anterior ambulacrum and a part of
the odd anterior ambulacrum.

1-2 are from a specimen of 70 mm. in diameter, and 3-4 from a specimen measuring
88 mm. in diameter, including the spines. The dotted lines join the radioles of the same
vertical row.

Bonin Ids., N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

COLOBOCENTROTUS PLATE 39.

"ALBATROSS TROPICAL PAGIFIGEX 1899-1900.

B.Meisel lith

AM. Westergren del

*

.
1
$F aki wesbey

Puate 40

ae 1-82. Colobocentrotus Stimpsoni A. Ag.
1-32. Spines.
1. Spine, from the buecal membrane close to the teeth.
2. Spine, from the actinal system.
-} Spine, lower side, midway between the actinal system and the ambitus.
4.) Spine, profile of same as 3. :
5. Spine, lower side, from the actinal side of the ambitus, from the left anterior

ambulacrum.

2

Spine, upper side.
Spine, lower side, from the actinal side near the ambitus, from the left anterior

~~

ambulacrum.

abe profile.

9.) Spine, upper side.

10. | Spine, lower side, at the ambitus, from the right posterior ambulacrum. These larger .
radioles vary in length from 12 to 15 mm.

11.) Spine, profile.

12.) Spine, upper side.

13. | Spine, lower side, from the abactinal side, near the ambitus, from the left anterior
ambulacrum. :

14.) Spine, profile. |

15.) Spine, upper side.

16. | Spine, lower side, from the abactinal side near the ambitus, from the left posterior
interambulacrum.

17.) Spine, profile. age

18.) Spine, top view. é

19. | Spine, lower side, midway between the ambitus and the abactinal system, from the v7
odd anterior ambulacrum.

20.) Spine, profile.

21.) Spine, top view.

22. | Spine, lower side, from the abactinal side towards the ambitus, from the left posterior
ambulacrum.

23.) Spine, profile. >

24.

25. ) Spine, lower side from the upper extremity of the left anterior ambulacrum.

} Spine, upper side, from the upper extremity of the left anterior ambulacrum.

) Spine, top view, from the upper extremity of the right posterior interambulacrum.

27.) Spine, lower side from the upper extremity of the right posterior interambulacrum.

28. Miliary spine, near the upper extremity of the right posterior interambulacrum, —
hidden by the primary radioles.

29. Miliary spine, lower side, from the anal system.

30. Miliary spine, lower side, from the anal system.

31. ) Miliary spine, upper side, from the anal system.

32. ) Miliary spine, profile, from the anal system.

The figures are from the same specimen, measuring 88 mm. in diameter.

All the figures are about equally enlarged, except the shaded figures 1, 2, 5, 28, which
are considerably enlarged, as is shown by the adjoining outlines.

Bonin Ids., Dr. Wm. Stimpson Coll.

‘ALBATROSS TROPICAL PACIFIC EX. 1899-1900. COLOBOCENTROTUS, PLATE 40.

AMWestergren del :

lith Ansty Wemer&Winter Franaiurt?M

PLATE 41.
1-7. Colobocentrotus Stimpsoni A. Ag.

1. The left anterior interambulacrum.
2. The ninth and tenth plates from the actinal system of the left anterior interambu-
lacrum. B

3. Showing the large tubercle of the fifth plate from the actinal system at the ambitus of
the left posterior interambulacrum.

The same, seen in profile. ‘

One of the primary interambulacral tubercles on the abactinal side.

Grouping of the miliaries on the actinal side of the right posterior interambulacrum.

Genital plate and pore of the left anterior interambulacrum.

All the figures are from the same specimen, measuring 88 mm. in diameter, including the

ue tn

spines.
Bonin Ids., Captains Ringgold and Rodgers, N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

1899-1900.

x

IFIG E>

GAL PAG

TROP

—> arn ea?
ALBATROSS

f

> AM Westergren del

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PuaTE 42, ; =

1-8. Colobocentrotus Stimpsoni A. Ag.

1. Interior view of the actinal side.

2. One of the pairs of perforated plates of the buccal membrane, facing the odd anterior
ambulacrum.

3. Exterior view of the odd anterior ambulacral plates adjoining the actinal system.

4. The same seen from the interior of the test.

5. The tenth plate from the actinal system of the odd anterior ambulacrum.

6. The same seen from the interior.

7. Interior view of a plate of the right posterior ambulacrum at the ambitus.

8. The ocular plate and the abactinal extremity of the left posterior ambulacrum, seen

from the interior.

In figures 3, 4, and 5, 6, a small cross shows the slanting perforation of the pore through
the test.

From a specimen measuring 88 mm. in diameter including the spines.

Bonin Ids., Captains Ringgold and Rodgers, N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

“ALBATROSS TROPIGAL PaciFic Ex. 1899-1900 GOLOBOGENTROTUS PLATE 42.

AM Westergren del

B Meisel rk

: PLATE 43.
1-7. Colobocentrotus Stimpsoni A. Ag.

The abactinal system, before being denuded of its spines.

The abactinal system of the same, denuded.

The same, seen from the interior of the test.

The auricles of the right posterior ambulacrum, seen from the interior of the test.

ar

The auricles as seen looking towards the actinostome through the auricular opening of
the left posterior ambulacrum.
6. Plates of the right anterior interambulacrum adjoining the actinal system, seen from
the interior of the test.
7. Plates of the odd posterior interambulacrum bordering on the actinal system.
Figs. 6, 7, seem to show the remnant of the ambulacral primordial plates.
From a specimen measuring 88 mm. in diameter including the spines.
Bonin Ids., Captains Ringgold and Rodgers, N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

"ALBATROSS TROPICAL PACIFICEX 1899-1900.

COLOBOCENTROTUS PLATE 43.

AM Westergren de]

B Meisel lith

wel &

eT iE § Dd

ees

+
5
,
a
- ay '&
‘
i

- 2 *

ou,

SOR CCES Slee Sol rth Ware) Ros

a a
NO

PLATE 44.
1-12. Colobocentrotus Stimpsoni A. Ag.

Lantern seen from above.

The same as 1, seen in profile.

One of the pyramids, seen from the exterior.

The same as 3, seen from the interior.

The same, seen in profile.

The same, seen from above.

a. Epiphysis of pyramid, from the interior, b. pyramid, in profile, from the interior.
a. Epiphysis of pyramid, from the exterior, b. pyramid, in profile, from the exterior.
Edge of the corrugated surface of pyramid somewhat more enlarged.

a. Groove of tooth, b. tooth seen in profile.

a. The brace, seen from above, b. seen in profile, c. from below, d. endwise.

a. Compass seen in profile, b. seen from above.

All the figures from a denuded specimen 65 mm. in diameter.

Bonin Ids., Captains Ringgold and Rodgers, N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

COLOBOGENTROTUS PLATE 44.

1

TFic Ex. 1899-1900

Pacr
EAGIF

TROPICAL

B Meisel lith

AM Westereren del

na

* Sealy batted are nr AE vs Mi? |
pet ah aller as hehe. sn r
> pre ate ha par bagt) Lacieish +, eden

: r seta ieny te Ti owd iA 2 2 3
piings | Spade Ort? ae 2 Ri sat . at = ; 2 = .

a ; _

> he te es, ¥ a : ae
a . Tal > i : ( . - =
-. a plstins 236 tedin 268% Be a ; —Ns a

= omer led, ¥20 ety Lag: > : rade Pe See se
Eis gordo a 8 Parmnap ary toh, a ates ~~ &
3 Rt See alle eo xi pe 3: :

sh ret 7 psist sions ty 5 = Feil (ik
Se SER i ot ea Se
7 wsherlawees deiisivibos as as See ele

a
a ba <<
, ee sali) “3 ae get : ie: a =
f ~ N — :
=. 7 an Oo r
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= "= - ae
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, = a 2
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a. as
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pats r
“j A . ‘ Ly
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oes a
= : =
me * ap @
ve ee > A” See
[We A 2S
ne ~~ £ ;
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7 ae —, if A
i
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6 _~
. a 2
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- .

PuLaTE 45.
1-5. Colobocentrotus Stimpsoni A. Ag.

The disk of an actinal pedicel.

The basal part of one of its lamine.
Part of a typical spicule.

A deformed spicule.

Sur eh

Fragment of a deformed spicule.

6-10. Colobocentrotus Mertensii Brandt.

Fragment of a spicule.

1

Basal part of a lamina.
Shows the quadratic arrangement of the spicules.

se

Typically formed spicule.
10. Top of a pedicel, taken from the abactinal side and hidden by the large radioles.
Figures 1-5 are from a specimen, 88 mm. in diameter including the spines and those
of 6-10 from an individual, measuring 70 mm. in diameter.
Bonin Ids., Captains Ringgold and Rodgers, N. P. Ex. Ex., Dr. Wm. Stimpson Coll.

1899-1900 COLOBOCENTROTUS PLATE 45.

S)
NI

OnE ah ot CA as, pst etaba

“ledourtinly wl ae
- en

* aa

i

10.
GF

PLATE 46.
144. Podophora pedifera Agass.

The odd anterior ambulacrum of a denuded specimen 55 mm. in diameter,
Pore near the actinal system, from the same specimen.
Pore at the ambitus.
One of the pores of the ninth plate from the actinal system.
5-8. Podophora atrata Agass.
The odd anterior ambulacrum of a denuded specimen 46 mm. in diameter.
Pore near the actinal system, corresponding to the pore of fig. 5.
Pore at the ambitus.
One of the pores of the eighth plate from the actinal system.

9-12. Colobocentrotus Stimpsoni A. Ag.
The odd anterior ambulacrum, of a denuded specimen 65 mm. in diameter.
Pore near the actinal system corresponding to the pore of fig. 5.

Pore at the ambitus.
One of the pores of the eleventh plate from the actinal system.

GOLOBOCENTROTUS PLATE 46.

1899-1900

TROPICAL PACIFIC Ex.

"ALBATROSS

B Meisel ith

AM Westereren del

-
‘ *
'
.
— _
‘

WMemoirs of the Museum of Comparative Zodlogy
AT HARVARD COLLEGE.

Vout. XXXIX. No. 2.

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE
TROPICAL PACIFIC, IN CHARGE OF ALEXANDER AGASSIZ, BY THE
U. S. FISH COMMISSION STEAMER “ALBATROSS,” FROM AUGUST, 1899,

to MARCH, 1900, COMMANDER JEFFERSON F. MOSER, U. S. N., COM-
MANDING.

XV.
ECHINI.

ECHINONEUS AND MICROPETALON.

By A. M. WESTERGREN.

WITH THIRTY-ONE PLATES.

(Published by permission of Georce M. Bowers, U. S. Commissioner of Fish and Fisheries. ]

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

Aveust, 1911.

CONTENTS.

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE TROPI-
CAL PACIFIC, in charge of ALEXANDER AGassiz, by the U. S. Fish Commission Steamer
**Albatross,” from August, 1899, to March, 1900, Commander Jerrerson F. Moser,
U.S. N., Commanding. XV. Ecuint: Ecutnonitus anp Micropetaton. By A. M.
WESTERGREN. With 34 pp. and 31 Plates.

TABLE OF CONTENTS.

INTRODUCTORY NOTE

ECHINONEUS CYCLOSTOMUS Lesxke
THE OUTLINE OF THE AMBITUS. Plates 4, 5
DEVELOPMENT OF THE CORONAL PLATES. Plates 6, 7, 13
ORAL AND ANAL SYSTEMS. Plate 15
THE ABACTINAL SYSTEM. Plate 14
THE SPHAERIDIA. Plates 16, 17
ARRANGEMENT OF THE TUBERCLES AND SCROBICULAR CIRCLES. Bia 24, 25

THE PEDICELLARIAE. Plates 18-23; Plate 26, figs. 16-19, 30, 31; Plate 27, oe 12, pee 23, 24,

35, 36, 43, 44
THE SPICULES OF THE TUBE-FEET. " Plate 28, “Ass = 4.
THE PERIPODIA. Plate 28, figs. 15-24 :
THE spINEs. Plate 26, figs. 1-15, 20-29; Plate 27, Fes, 1- il, 14-29, 25-34, 37- 42
THE LANTERN AND AURICLES. Plate 11, figs. 1, 2, 7, 8; Plate 12 . . :
THE ALIMENTARY CANAL. Plates 8-10; Plate 11, figs. 8, 9

MICROPETALON PURPUREUM A. Aaassiz ano H. L. Cuarx. Plates 29-31 .
LIST OF SPECIMENS

SYNONYMICAL LIST

PLATES.

41

At
46
47
49
50
51

53
57
58
59
60
61

63
65
66

TROPICAL PACIFIC ECHINI.

ECHINONEUS AND MICROPETALON.

INTRODUCTORY NOTE.

Av the time of his death Mr. Agassiz had in view the publication of a Report
on the genus Echinonéus, the illustrations for which I had worked upon, first
in 1903 and later in 1908, until their completion in August, 1910.

The material in the collections in the Museum of Comparative Zodlogy
at my disposal for study and for the preparation of the illustrations was excellent
there being no less than two hundred and forty-four specimens of which one
hundred and sixty were alcoholic, and the remainder dry bare tests. They range
in size from a length of about three millimetres up to nearly forty. They come
from different localities in the West Indies, the Pacific and East Indian regions.

Besides the above Dr. Richard Rathbun of the U. 8. National Museum
had the kindness to send for comparison two perfect adult specimens in alcohol,
collected during U. 8. Eclipse Expedition of 1889 to West Africa, which though
labeled Ascension Is.,? were probably obtained at Barbados.

As a result of the examination of this material, Mr. Agassiz had reached the
conclusion that it represents a single species, for which cyclostomus Leske (1778),
seems to be the earliest available name. Linne’s name ovalis (1753) would
have been preferable but unfortunately was used prior to 1758.

From Mr. Agassiz’s paper ‘“‘On the existence of teeth and of a lantern in
the genus Echinonéus Van Phels” (Amer. Journ. Sci., November, 1909, ser. 4,
28, p. 490-492, pl. 2) I quote:—

“This is perhaps one of the most interesting recent discoveries in the
domain of echinology, considering the relationship hitherto recognized of Echino-
néus to the Atelostomata. The presence of teeth would transfer them to the
vicinity of such types of the exocycla Gnathostomata as Holectypus, Discoidea,
Pygaster (Echinoconide) and more remotely to the Conoclypide. * * *

“Young specimens of Echinonéus * * * and but slightly larger than those

42 TROPICAL PACIFIC ECHINI.

in which teeth were observed, have no teeth or lantern * * * and nothing is
left of them * * * so that in the older and adult stages of Echinonéus its
relationship to the Spatangoids is in no way modified. * * +

“Tt is interesting to note that this dentate stage of Echinonéus should
connect the embryonic Spatangoids with the early stages of Clypeastroids and
of the Echinoconide, while the toothed Pygastroides of Lovén connects it with
some of the Echinoconide; both Echinonéus and Pygastroides are West Indian
genera.

“The presence or absence of auricles, teeth and pyramids forms the basis
of Zittel’s classification of the irregular Echini into Gnathostomata and Atelo-
stomata. The position of the anal system on the actinal surface close to the
actinostome is a very modern feature: its gradual passage from an anal system
enclosed within the calycinal system as in Pygaster, where it is outside of the
abactinal system, can be traced towards the ambitus to the ambitus and finally
to an actinal position.

“In some of the Holectypide the jaws are greatly reduced in size and
solidity and their importance much lessened, and in others the Jaws have entirely
disappeared, the perignathic girdle having become rudimentary. In the Echino-
metrade the auricular girdle is most highly developed. In the Holectypide
we find primitive irregular Echini as well as types which have persisted to the
present day. In the Discoidea and Galerites the ambulacral processes and
teeth are absent; in the auricular girdle the processes become low. In the Cly-
peastroids there are neither braces nor compass, the jaws move horizontally,
and finally in the Atelostomata the girdle and jaws are completely absent. We
may imagine the process of resorption of the lantern of Echinonéus to have gone
through some such succession.”

The specimens upon which Mr. Agassiz based the above remarks were
collected by Dr. H. L. Clark who has kindly supplied the following notes:—

~ Echinonéus occurs at Port Antonio, Jamaica, only in the sand-flat within
the reef on the north and west sides of Litchfield Point. Search in similar
habitats in the vicinity of Port Antonio, both in 1897 and in 1909, failed to
reveal a single specimen.

“On this sand-flat, which is more or less covered by a feeble growth of
short eel-grass, are numerous fragments of coral-rock, ranging from a few inches
to two or three feet in diameter. These fragments are more or less imbedded
in the sand and it is under them that Echinonéus occurs, commonly in company

with Brissus unicolor Klein. As a rule, both these species are completely buried

ECHINONEUS CYCLOSTOMUS. 43

in the sand and are found only by sifting the sand. A flour scoop proved the
best implement for digging up the sand, and then passing it through a set of
sieves, the lowest having a very fine mesh. By the use of such sieves some small
specimens were obtained which it would have been practically impossible to
have obtained in any other way. In rare instances, specimens were found
clinging to the rock overturned, but as they were clinging by the abactinal tube-
feet, it is evident they were only accidentally pulled up with the rock. Careful
examination of the sand around the rock-fragments (not beneath them) and
in areas not under rocks always failed to reveal Echinonéus or Brissus. It seems
as though rock-fragment were the essential factor in determining the exact
habitat. This may however be true in very shallow water only, for the Litch-
field sand-flat is covered at high tide by only 1-3 feet’ of water and at low tide
much of it is bare.

‘As in many regular Echini, the tube-feet of Echinonéus are used to hold
sand-grains and particles of dirt close against the test, thus more or less con-
cealing the animal.

“‘For this reason specimens only a few millimeters long are very hard to see,
the large flat grains of sand (derived apparently from calcareous Algae) afford-
ing an admirable means of concealment. When placed in a glass dish of sea-
water, without any sand, Echinonéus stretches the abactinal tube-feet out
far beyond the spines as though hunting for something, but after a short time,
they are retracted below the spines. If sand is present the animal soon covers
itself. In or on a sufficient amount of sand, the movement of the animal is
very evident. Both spines and tube-feet appear to be used in locomotion.

“The color of Echinonéus is whitish with a more or less marked reddish
tint. One small specimen was found the whole abactinal surface of which was
deep red. The tube-feet are clear, translucent red (more rose than scarlet,
yet not a rose-red), in marked contrast to the test and spines, so that the ambula-
cra stand out sharply. The color seems to be very easily affected by reagents,
becoming much darker than normal in alcohol, or glycerine. Formalin turns
the red shades to yellowish green ultimately becoming greenish yellow. A
strong salt solution (NaCl in fresh-water) kept the colors fairly well for a short
time (2448 hours) but specimens so treated afterwards became dingy brownish.
Mixtures of aleohol and formalin and of alcohol, formalin and glycerine were
of no avail, whether made up with fresh- or sea-water. The specimens which
are now nearest natural color are certain young ones treated only with pure
alcohol or pure glycerine.

+t TROPICAL PACIFIC ECHINI.

“Tn size, Echinonéus rarely exceeds an inch in length. The specimens
taken range from 4 to 27 mm. Most of them are between 8 and 18. The form
of the test is very variable, the proportions of width to length, height to width,
ete. showing much diversity. (In 1897, a bare test was found 42 mm. long.)

“Tt is quite possible that large specimens occur in deeper water, outside the
reef, but this is simply a conjecture.

“The absence of specimens less than 4 mm. long is greatly to be regretted,
but it seems almost certain that such young ones must occupy a different habi-
tat from the adults. Since it is probable that there is a free swimming larval
stage, it is quite possible that the absence of specimens under 3 mm. in length
from the sand where the adults occur may be explained as follows:— after the
metamorphosis, or at least at the conclusion of the free-swimming stage, the
young Echinonéus settles on the calcareous Algae, eel-grass, or other vegetation
surrounding undisturbed fragments of coral rock on the sand-flat, and only
slowly moves downward to and into the sand beneath the rock. By the time

the sand is reached, the Echinonéus is 2 or 3 mm. in length.”

Echinoneus cyclostomus Leske.

THE OUTLINE OF THE AMBITUS.
Plates 4, 5.

With material limited to a few specimens the specific characters seem easily
distinguished, but with an abundance of specimens the supposed differences are
at least doubtful. Pls. 4 and 5, give a far better idea of the characteristics
of the test than any description.

The figure of a fossil E. michaleti given by Cotteau and of de Loriol’s E.
abnormalis from Mauritius, are exactly identical in outline with the one shown
(Pl. 5, fig. 4) from Mauritius, and also with that collected in 1868 by Count
Pourtalés at Caryfort Reef, Florida (PI. 5, fig. 17) all of which have an almost
circular ambitus; the anal system in the smallest Florida specimen being much
longer than in the other.

In comparing two specimens of nearly equal length from the same locality,
Lord Lowe Island, N.S. Wales (PI. 5, figs. 1, 2), it will be seen that the ambitus
of the smallest, fig. 1, is between an ovoid and a pentagon in shape, and that the
anal system is elongated, while in the other, fig. 2, the ambitus is unevenly
pointed at the anterior end with a longer distance between the anterior ambula-

crum on the left side and the anal system is short.

ECHINONEUS CYCLOSTOMUS. 45

The ambitus in a specimen from Mauritius, Pl. 5, fig. 4, is circular, while
in two adult specimens, also collected at Mauritius in 1873, only one of which
is figured, Pl. 5, fig. 3, it is more ovoid in shape with a broad blunt posterior
end; and the well-defined tubercles, the raised and rounded ambulacra, show
little similarity to any of the other figures on Pls. 4 and 5.

Diversity in the shape of the ambitus is also shown on PI. 4, figs. 7, 20, and
Pl. 5, figs. 7-10; all the specimens figured are from the Pacific and by the same
collector. On PI. 4, fig. 7, the ambitus is an ellipsoid and the mouth and anus
are small; the outline of the test is compressed to an ellipsoid with a posterior
pointed end, and the anal system is elongated, nearly reaching the ambitus,
(Pl. 4, fig. 20). The same irregularity of the ambitus is shown (PI. 5, figs. 7-10),
and the actinostome and anal system varies in form and size out of proportion
to the length of the tests. These specimens were water-worn, the tubercles being
partly destroyed.

A specimen from Makemo Island, Paumotu Islands, Exped. ‘‘ Albatross”
1899-1900, presents an actinostome and anal system toward the right side of the
test; in other specimens the odd anterior‘ambulacrum also frequently inclines
toward either the right or the left side.

The larger of two specimens from Bourbon (Pl. 4, figs. 3, 11), recalls the
specimen from Lord Howe Island (PI. 5, fig. 2), and the smaller one is identical
with that from Makemo Island. Three tests from the Gilbert Islands (Pl. 4,
figs. 12, 15, 18), of nearly the same size, are unlike in shape but are in every way
similar to the young specimen from Mujeres Island, Yucatan (PI. 4, fig. 19).

Comparison of two specimens of about the same size from Cuba, one (PI. 4,
- fig. 23), ellipsoid, and one (Pl. 5, fig. 17), with long ellipsoid ambitus nearly
one third longer than its breadth, shows little or no conformity to two individuals
(Pl. 5, figs. 15, 16), from Port Antonio, Jamaica, the larger of which is ovoid
in outline, the smaller ellipsoid with slightly projecting ambulacra, and large
actinostome. Of three young specimens also from Port Antonio, the two small- _
est (Pl. 5, figs. 12, 13), are ovoid in outline, while the third (PI. 5, fig. 14) is
ellipsoid with a slight deviation in character towards a young specimen of the
same size from Mauritius (PI. 5, fig. 5).

Profile views of the tests strengthen the opinion that variation in shape is
not wholly due to disparity of age or locality. In two adult specimens of the
same length, one from Barbados (PI. 2, fig. 3), the other from the Pacific (PI. 3,
fig. 5), the shape of the profiles are exactly alike, with equally curved actinal
and abactinal outlines. A third specimen (PI. 4, fig. 9), from Makemo Island

46 TROPICAL PACIFIC ECHINI.

has the actinal surface on the anterior end rounded outwards, with the abactinal
side in the apical region depressed. It is not unusual in large specimens to find
the same features as are shown in a specimen from Gilbert Islands (PI. 4, fig. 13),
with its actinal side perceptibly arched, or as in specimens from the Pacific
(Pl. 4, fig. 21), and Cuba, (PI. 4, fig. 24), with straight tests and narrow posterior
ends. The test seen from the anterior end facing the odd anterior ambulacrum
(Pl. 4, figs. 5, 10, 14, 17, 22), varies in outline from ovoid to spherical and fre-

quently, as in Pl. 4, fig. 10, one side is higher than the other.

DEVELOPMENT OF THE CORONAL PLATES.
Plates 6, 7, 13.

The arrangement of the primordial ambulacral plates in each ambulacrum
is the same as in the spatangoids, and follows the formula given in Lovén’s
Etudes; usually the sueceeding two pairs or so are simple plates after which
they are in groups of three of which the upper is the largest. This plate is
somewhat broader at the median ambulacral suture; the second one, a demiplate,
is wedged in between the first and third, the latter being quite low. In the adult
these plates, (Pl. 13, fig. 5), on the abactinal side are very low and about four
times as broad as they are high. Each plate, except the largest one, has a
double perforated pore, in the edge of the actinostome (PI. 13, fig. 3); the larg-
est plate has three perforations, the one towards the oral plastron being open.

In the young from Port Antonio, with the test 5.90 mm. in length, the
shape of the actinostome is nearly circular; there is a primordial plate in each
interambulacrum (PI. 6, fig. 1); and the same condition obtains in a specimen
from Makemo Island (Pl. 13, fig. 1), the test of which measures 4.40 mm. in
length.

In the adult the shape becomes a triangle with its horizontal side limiting
the bivium, and the vertical side running between the right anterior inter-
ambulacrum and the right posterior ambulacrum; its anterior and left poste-
rior corners usurp a part, or the whole, of the primordial plates in the right
anterior and the left posterior interambulacra, cf. Pl. 7, a specimen from
Mauritius, with test 37 mm. in length and also my earlier sketches in Lovén’s
Etudes (Pl. 9, figs, 82, 83). An adult specimen, 27 mm. in length, from
Makemo Island shows (PI. 13, fig. 2) the way this reabsorption varies; all the

primordial plates are still in place and but little diminished in height.

ECHINONEUS CYCLOSTOMUS. 47

So far as I know the labium in the spatangoids undergoes little or no change
in form, while in Echinonéus, even from a single locality, there is much variety;
for instance in two young specimens from Port Antonio, 4.19 mm. (PI. 6, fig. 2),
and 5.90 mm. in length (PI. 6, fig. 1), the labium is almost three cornered and
shut out from the anal system by the first pair of interambulacral plates; while
in one, 6 mm. long (PI. 6, fig. 3), the broad base of the labium borders on the
edge of the anal system just as in a specimen, 4.40 mm. in length, from Makemo
Island (Pl. 13, fig. 7). In two adult tests of practically the same size, 22, 25
mm. in length, from Port Antonio (Pl. 6, figs. 5, 6), the labium of the former
(fig. 5) is T-shaped with its smaller end on the anal system, while in the latter
(fig. 6), only asmall strip in the edge of the actinostome remains, the same as in
a specimen of about the same size, 27 mm. in length, from Makemo Island (PI. 6,
fig. 8).

The actinal interambulacral plates are nearly as high as broad. At the
ambitus where the test is ellipsoid they are higher than when it is ovoid, and
continue thus on the abactinal side.

The peculiar way in which the plates overlap in the median interambulacral
suture is not fully shown in Pl. 13, fig. 4. The apparent continuation of the
ambulacra on to the interambulacral plates (Pl. 13, fig. 5), may be simply

impressions due to the attachments of soft parts.

ORAL AND ANAL SYSTEMS.
Plate 15.

Among the specimens collected at Port Antonio, the smallest measures 3.70
mm. in length; the oral plastron is devoid of plates, its actinostome, measuring
1.18 mm. in diameter, and is nearly circular, becoming triangular by growth
as described in the development of the coronal plates. When-further developed
and adult the oral plastron is covered with solid, glossy plates without tubercles,
imperfect polygons or rectangles in form. They are laid in irregular curves
(Pl. 15, figs. 2, 3, 4, 6), and could serve as an orbicular shutter; their function
is possibly the same as that of the teeth.

Upon comparing the shape of the anal system in a number of specimens
from the West Indian and Pacific regions I find an indefinite irregularity in the
outline; as for instance two tests from Lord Howe Island and of same size (Pl. 15,
figs. 3, 4), in the first (fig. 3), the opening is large and irregularly ovoid, while

in the other (fig. 4), it is noticeably shorter, with its angular base or aboral end

48 TROPICAL PACIFIC ECHINI.

towards the ambitus. In an adult specimen, with a test 27 mm. in length,
from Makemo Island (fig. 2), the anal system is elongated, ellipsoid, with pointed
adoral and aboral ends; and in two other specimens (figs. 5, 6), 27 mm. long,
from Mauritius, the opening in fig. 5 is broader with the aboral end pointed,
while in fig. 6 it is more symmetrically ellipsoid. Two young specimens from
Port Antonio, tests 6 mm. and 10 mm. in length, show the same diversity;
one (fig. 8), is smaller and an ellipsoid; the other (fig. 9), with its aboral end
running into a sharp point, has little or no similarity to a specimen from Florida
(fig. 11), which also differs from an adult individual from Barbados (fig. 12);
in the latter the opening of the anal system recalls that of the specimen from
Mauritius (fig. 5). In a specimen 29 mm. long from Bourbon (fig. 7), the out-
line with its broad rounded aboral end, has no similarity to any of the other
figures given on Pl. 15. This change in outline and size of the anal system,
which is probably caused by the amount of resorption in the first six or seven
pairs of interambulacral plates, makes the anal system valueless as a specific
character.

The order in which the plates are arranged on the buccal and anal plastrons
in other families of the spatangoids has hitherto been regarded as irregular and
of slight consequence. The figures given on Pl. 15 of the anal plastron show
a remarkable regularity in the grouping of the plates; about seven to nine of.
which are laid on the plastron adjoining the interambulacral plates with the
largest ones in the adoral end slightly raised. The aboral end has three or
more large plates with the addition of a number of small ones surrounding the
anal outlet. In the specimens from the Pacific the largest plates on the plastron
towards the adoral end, are separated at the median line either by a large plate,
or a double row of rhomboidal ones, while in the West Indian specimens these
plates are replaced by a number of long slender calcareous strips, which make
the surface flexible. This is the only differential point I find between the
Pacific and West Indian specimens, and it accords with Mr. Agassiz’s statement,
Revision, p. 334-335.

ECHINONEUS CYCLOSTOMUS. 49

THe ABACTINAL SYSTEM.
Plate 14.

At first it was intended to limit this report to a few plates, and a more
careful examination of the abactinal system was left for the future.

In a young specimen from Makemo, 4.40 mm. in length, interior view (PI.
14, fig. 2), none of the genital plates have received their pore, excepting a few
madreporic perforations on the madreporite. Of the two posterior genital plates
the one towards the right posterior interambulacrum is slightly larger than its
mate; both are about as high as broad and in contact with the ocular plates in
the bivium; of the two anterior ones the madreporic is the larger. Seen from
the exterior (fig. 7), the apex is slightly raised, carries a few miliaries and a
small number of the glassy tubercles.

Another specimen 4.19 mm. in length, from Port Antonio (Pl. 14, fig. 3),
differs from the previous one only in the left anterior genital being slender, and
the right posterior genital having pushed itself between the ocular plates of the
bivium, which in fig. 2 are in apposition.

Of two specimens, one 12.5 mm. long from Port Antonio (Pl. 14, fig. 4),
the other 27 mm. in length (PI. 14, fig. 7) from Makemo, the genital plates corre-
spond exactly to each other in form and size; the anterior plate being longer
than the posterior which is the reverse of what is shown in figs. 2 and 3; here the
two large plates are posterior, with the larger one in the right posterior inter-
ambulacrum, while in figs. 4 and 5 these are in the left posterior interambula-
crum. The system of the four genital plates are arranged in a square and are
in contact; their form and that of the pentagonal shaped ocular plates are very
similar to the figure of Hemiaster expergitus in Lovén’s Etudes (PI. 11, fig. 93),
and of Periaster tenuis in Agassiz’s Panamic deep sea Echini (p. 210). In two
specimens (PI. 14, figs. 5, 6), from the Pacific, measuring 26, 27 mm. in length,
one (fig. 5) has very small genital pores, about one third the size of the other
(fig. 6); this may be due to sex; the glassy tubercles are larger, darker, and
more numerous in fig. 5 than in fig. 6. This variation is found in alcoholic as

well as in dry specimens.

50 TROPICAL PACIFIC ECHINI.

THe SPHAERIDIA.
Plates 16, 17.

Thirty-three figures of the sphaeridia from tests of intermediate sizes
varying from 10 to 34 mm. in length, and from various localities in the West
Indian and Pacific regions, are given on Pls. 16 and 17. No two are exactly
alike, neither do they show any specific characteristics; but some of them corre-
spond in form to those of Maretia or Brissopsis, ¢f. Lovén’s Etudes, Pl. 1.

An examination of the sphaeridia in Echinonéus shows their height to be
greater in proportion to the size of the test in the smaller specimens than in those
full grown. The largest sphaeridium of a young specimen, from Makemo Island,
10 mm. long, is 0.10 mm. in height; in another from Fakarava Island, 12 mm.
in length, it is 0.13 mm., and a third from Barbados, with the test 26 mm. in
length, has the highest 0.20 mm., while an adult specimen from Lord Howe Island
34 mm. in length or three times as long as the youngest from Makemo Island,
has its sphaeridia only 0.16 mm. in height.

Among the material at the Museum I found only three sphaeridia to each
ambulacrum, although Lovén’s Etudes (Pl. 9, fig. 79), gives four. There are
searcely two alike from the same ambulacrum; some have an uneven papillate
surface, but commonly they are almost smooth. The row of sphaeridia (PI. 16,
figs. 1-4), taken from odd anterior, right anterior, left anterior, and left pos-
terior ambulacra respectively of a specimen from Fakarava Island, 12 mm. in
length, vary in form with no indications of specific characters. Of six sphaeridia
(Pl. 16, figs. 5-8), from two specimens from Lord Howe Island, 30 and 34 mm.
in length, two (fig. 5) from the odd anterior ambulacrum are 0.16 mm. high, one
of them being spherical with a wavy outline, the other smooth and pointed at
the top; one from the left anterior ambulacrum (fig. 6) is depressed with flattened
top; another from the left posterior ambulacrum (fig. 7), has a spherical outline,
slightly truncated at the upper end. Two others (fig. 8), from the right anterior
ambulacrum of a specimen measuring 30 mm. are 0.18 mm. high; one is unevenly
cylindrical in outline, the other ovoid. This irregularity of form (Pl. 16, figs.
13, 14), can be traced even in the young test measuring 10 mm. in length.

In ten figures from the different ambulacra (Pl. 17, figs. 1-6), of two speci-
mens, from Barbados, measuring 26 and 30 mm. in length, the height of the
sphaeridia varies from 0.17 mm. to 0.20 mm. This variation which exists
between the sphaeridia is further accentuated as shown in fig. 1 where the sphae-
ridium from the right posterior ambulacrum is ovoid with two points at the top,
its companion being ellipsoid with a sharp upper end. There is still another form,

ECHINONEUS CYCLOSTOMUS. 51

that of a one-sided sphaeridium (fig. 3) from the odd anterior ambulacrum which
contrasts with the circular chipped outline (fig. 4) and its ovoid mate, from the
left anterior ambulacrum. Dissimilarity is also observable (fig. 6), where the
first sphaeridium is ovoid and the other club-shaped; both came from the
right anterior ambulacrum of a specimen 26 mm. long.

It is noticeable that the five figures on Pl. 17, figs. 7-9, are not exactly like
those on Pl. 16, figs. 1-4, although the specimens came from the same place,
Fakarava Island. It should, however, be observed that they were taken from

two specimens, one 12 mm. the other 23 mm. in length.

ARRANGEMENT OF THE TUBERCLES AND SCROBICULAR CIRCLES.
Plates 24, 25.

De Loriol mentions the tubercles and scrobicular circles as specific charac-

ters.' In perfect specimens, on the actinal side near the actinostome in the

interambulacral area, the primary tubercles may be for the most part without
a scrobicular area, but surrounded by large glassy tubercles. In other speci-
mens of the same size, from the same locality, the boss is deeply set on the test,
and the serobicular circles are transformed to open angular cells, with a small
number of miliaries and a few minute glassy tubercles on their edges. (Pl. 25,
fig. 9.)

The primary tubercles on the actinal side are nearly uniform in size and
arranged in horizontal rows. <A few of the plates nearest the actinostome have a
single line, after this each plate has two; in the region of the ambitus, and for
some distance above, the tubercles run diagonally as well as horizontally, and
they vary in number according to age. They are smallest in the odd posterior
interambulacrum.

The seventh plate from the actinostome, including the primordial, in the
left anterior interambulacrum of eight specimens from Port Antonio, measuring
from 4.19 mm. to 17 mm. in length (with an interval of about two millimetres
between each) is shown on PI. 25, figs. 7-8. In the smallest specimen, 4.19 mm.
in length (fig. 1), this plate is on the abactinal side, and has, besides a few milia-
ries, only two of the primary tubercles, one being towards the upper corner
near the median line. In the next smallest, 6 mm. long, this seventh plate (fig. 2)

is on the actinal side, and has its third tubercle near the upper outer corner; all

1 Two specimens from Mauritius, 36 and 37 mm. in length, resemble de Loriol’s E. abnormalis,
but the mamelon is without a perforation.

52 TROPICAL PACIFIC ECHINI.

three are grouped in a triangle with the base upwards. These three first pri-
maries are recognizable in fig. 3 (8 mm.), and fig. 4 (10 mm.), the latter having
an increase of two primaries in the lower part, one being towards the outer
side, the other near the median line. In fig. 5 (12 mm.), the seventh plate is
not quite normal, but it shows the same regularity. When a length of about
15 mm. (fig. 6) is reached, the upper row has four primaries, one of the new comers
being near the outer margin, the other, which is the smallest near the median
suture. In a test of 17 mm. (fig. 7), and an adult of 26 mm. (fig. 8), there
is no increase of the primaries, but they are arranged as previously described.
The miliaries vary in number. The glassy tubercles are minute, few, and fre-
quently absent.

While there are only four of the primary tubercles in the upper row in these
specimens, Pl. 25, figs. 1-8; when the test is broadly ovoid with a length of
35 mm. or so, they have gradually increased to eight or more.

A comparison of the primary tubercles on the ambulacrum in specimens
of various sizes and different localities shows a regular order in their appearance.
The odd anterior ambulacrum was selected for illustration, and in the extensive
material examined from Port Antonio, there was no deviation so long as the
specimens were normal. The smallest specimen, 6 mm. in length (PI. 24, fig. 7),
has two rows of primary tubercles, one on each side of the ambulacrum adjacent
to the ambulacral pores. The first primary of the next line, the third, has its
seat in front of the fourth tubercle from the actinal system as shown, Pl. 24,
fig. 1-7. This third row in fig. 2, test 8 mm. long, curves towards the left side
of the ambulacrum, to make room for the fourth which commences on the
right side near the second tubercle of the third row, as seen in fig. 3, a test of
9.5 mm., and fig. 4, test 11 mm. long. A fifth row has its first tubercle above
or close to the third primary of the fourth line, as in two specimens, 16 and 18
mm. long, figs. 5 and 6. The latter specimen (18 mm.) has the sixth or last
row to the right of the fifth, beginning at the right of the first tubercle in the
fifth row. Some of the central rows extend only to the actinal and abactinal
region of the ambitus. The odd anterior ambulacrum of a test 27 mm. long,
from the Pacific (fig. 7), shows exactly the same number of rows and order of
grouping in the primary tubercles as is seen in those from Jamaica.

The glassy tubercles are mostly ovoid, with their lower half in the test,
flattened at the top with corrugated sloping sides, armed with small sharp points
(Pl. 25, figs. 11, 12). They are either colorless, or of a blackish tint, until freed

from the test when they become transparent.

ECHINONEUS CYCLOSTOMUS. 53

THe PEDICELLARIAE.
Plates 18-23; Plate 26, figs. 16-19, 30, 31; Plate 27, figs. 12, 13, 23, 24, 35, 36, 43, 44.

How great the variation of shape can be in pedicellariae of the same kind,
taken from the same specimen, but from different parts of the test, is shown in
the illustrations (Pls. 18-23) which are few when compared with the material
available. To distinguish which valve of the three in any one pedicellaria is
meant, since they are not of equal height, or the same form of loop, I have used
in addition to Mortensen’s comprehensive terminology, the letters A, B, C; A,
denoting the highest, C, the lowest, and B the intermediate valve.

The tridentate pedicellariae are few in number, and found only on the
actinal side of the test, near or a short distance from the oral and anal systems.
Of three valves from the same pedicellaria (Pl. 18, figs. 1-6), from a specimen
34 mm. long, from Lord Howe Island, no two of them have outlines exactly
alike. The blade in valve A (fig. 2), at the upper part is ellipsoidal, and does
not correspond to valve B (fig. 3), where it is circular; while in valve C (fig. 5),
it is slightly pointed. We find the same irregularity in the base, which either
slopes, or has a sharp prolongation on the right or left side close to the neck.
A valve of another pedicellaria (Pl. 18, figs. 70, 11), has no indication of the
articular loop, and the blade is possibly broken. Presumably it is a young
tridentate pedicellaria.

For uniformity one of the series valve B, was chosen for comparison. Three
such valves (Pl. 18, figs. 7, 9), from a specimen 15 mm. long from Makemo
Island, were taken respectively from near the actinostome in the odd posterior
interambulacrum, from the odd anterior ambulacrum, and from the right ante-
rior interambulacrum. The obvious difference in the form of the blades, which
vary from a triangular point to a round top, in the variation in number of lateral
teeth from 11 to 15 in each blade, and in the shape of the neck and bases, is most
striking. They are very unlike those on PI. 20, figs. 8, 10-13, also from Makemo
Island specimens. I find no specific identity between two valves (PI. 20,
figs. 8 and /0), from the same specimen, 10 mm. long; one valve from the aboral
end of the anal system, the other from midway between the actinostome and the
ambitus, in the right posterior interambulacrum. In one of these the blade and
base are of nearly the same height, while in the other the outline of the base is
rounded, the long neck abruptly narrowed, and the blade short with indications
of lateral teeth. In valve C (fig. 11), from another specimen 11 mm. long,

these lateral teeth are very conspicuous. The same striking difference is observ-

o4 TROPICAL PACIFIC ECHINI.

able in a valve B (fig. 12), and a valve C (fig. 13), from a specimen 18 mm.
long; in the former the blade and base are of about the same size, while in the -
latter the base is diminished in size and deltoid in shape.

When selecting valves for illustration from a number of specimens from
Fakarava Island, ‘‘ Albatross”? Exped. 1899-1900, I decided, after some hesita-
tion, upon figures to show the greatest extremes in form; thus Pl. 19, fig. 5,
valve B, with a triangular base, has a remarkably long neck and minute blade
without serrations, and this has little similarity to a valve A (Pl. 19, fig. 2),
with serrations and large lateral teeth, or to a valve B (fig. 3), with its large
ovoid blade, comparatively short neck, and rounded outline of the base, which
in valve C (fig. 4), is irregular. In connection with these it is interesting to
note that in a specimen from Barbados, 26 mm. long, I find some of the triden-
tate valves (PI. 19, fig. 7), showing the character of those from Fakarava Island
(Pl. 19, figs. 1-4). The only dissimilarity is in the outline of the base, which
in the specimen from Barbados, is armed close to the neck on both sides with
large prolonged points.

Between three specimens 11, 12, and 13 mm. long, and one 19 mm., all from
Fakarava Island, I should not expect to find great dissimilarity, but valves
A, B, C, from the same pedicellaria in the smallest specimen, have broad rounded
blades with large lateral teeth and stout symmetrical bases, which including
the articular loop, are as long as the blade. Their form has no similarity to a
valve B (PI. 20, fig. 5), from midway between the actinostome and the ambitus
in the right anterior interambulacrum, or to another valve B (PI. 20, fig. 6),
from near the actinostome in the right anterior interambulacrum, which has a
long deltoid base, and short triangular blade; neither is it like another valve B,
(Pl. 20, fig. 7), from the adoral end of the anal system. Even fig. 9, a valve B,
with its well-marked lateral teeth differs from the others.

The material from Port Antonio shows still further diversity as seen in a
comparison of nine valves of the series B, one of them (PI. 23, fig. 12) from the
odd posterior interambulacrum, actinal side, near the ambitus, with its broad
neck which gradually unites to the blade, contrasts with one (fig. 73) from the
aboral end of the anal system, in which the blade is nearly circular. Both
valves are of equal height, and from the same individual, measuring 25 mm.
in length. I find another case of a valve (fig. 14) from the adoral end of the
anal system of a specimen 26 mm. long, where the remarkably large base is
almost square, the blade broad and short, and ending in a sharp point; this is
quite unlike a valve (fig. 15), from the left posterior interambulacrum near the

ECHINONEUS CYCLOSTOMUS. 55
actinostome from a spetimen 28 mm. long, which has the edge of its long neck
bent inward like a collar, and which in turn contrasts to figs. 9-17, Pl. 23. The
first one from a specimen measuring 11 mm. in length, and the two latter from
one 20 mm. long. In a young specimen of 4 mm., the valve B (fig. 1), from the |
anal system, and (fig. 2), from the right posterior ambulacrum, near the actino-
stome, already have a difference in their shape.

It should be noted that tridentate pedicellariae (figs. 17—26) were owing to
insufficient space on the preceding plates placed on Pl. 22. The specimens were
from the Paumotu Islands, South Pacific, and from the West Indies, and the
figures readily show their diversity in shape.

The ophicephalous pedicellariae are the most numerous, especially on the
abactinal side, and they vary the least in form. Three valves, same pedi-
cellaria (Pl. 21, figs. 3, 4, 6), from the left posterior interambulacrum, of the
actinal side of the ambitus, from a specimen 34 mm. long, from Lord Howe
Island can be regarded as typical; but a large number deviate as will be seen
in valve C (fig. 7), and valve A (fig. 8), from the actinal side of the ambitus in
the right posterior interambulacrum, and especially in valve A, with its long
slender neck and articular loop pointed at the lower end. Of course a difference
in shape is to be expected between pedicellariae from the abactinal side of the
test, or near and on the apex, and those from the actinal side. This is shown
in two valves, B (fig. 9), and C (fig. 10), of the same pedicellaria, from near
the apical system of a 30 mm. specimen when compared with the figures referred
to above. In valve B which is practically of the same height as that shown in
fig. 4, the blade with a broad apophysis passes into the base almost without any
neck; the articular loop is stout and sharp pointed at its lower end; the articular
teeth are wide, and the articulation surface slopes to the left where the loop is
thickest; this is reversed in the other (fig. 4), where it slopes to the right; this
reversal is a common occurrence. Two valves, B and GC, in height 0.16 mm.,
from the apical system, of a specimen 11 mm. long, from Fakarava Island
(PI. 21, figs. 17, 12), do not present any great deviation from two others, B and C,
0.21 mm. in height from the actinal side of a specimen 15 mm. long, from
Makemo Island, (figs. 13, 14).

Of three valves, the same pedicellaria from the right posterior ambulacrum,
near the anal system, from a specimen 30 mm. long, from Barbados (Pl. 21,
figs. 15, 17), the blade has lost its discoidal form, and passes into the base almost
without any neck. The loop is that of an ophicephalous pedicellaria, but the
base and blade are exactly those of a tridentate form, and this may be noted

even in valves (figs. 18—20), from the abactinal side up to the apical system.

56 TROPICAL PACIFIC ECHINI.

One might regard this as a specific character for the West Indian species,
but it is not characteristic of those from Jamaica. Two valves, A and B (PI. 23,
figs. 3, 4), from the odd posterior interambulacrum, near the anal system, in a
young specimen 4 mm. long, from Port Antonio, resemble those of a typical
ophicephalous pedicellaria. :

The globiferous pedicellariae were found only near the ambitus, and on the
abactinal system in the two specimens from Lord Howe Island, and in a small
specimen from Fakarava Island; besides these there were some near the summit
in the two individuals from Barbados, and in the specimens from Jamaica.
These pedicellariae (Pl. 22, figs. 1-16, Pl. 23, figs. 5-8), are essentially alike in
the different specimens, although they vary more or less in outline.

In three valves of the same pedicellaria, from the left anterior ambulacrum,
on the actinal side toward the ambitus, the pointed blade is nearly as long
as the base (Pl. 22, figs. 3-6), with twelve strong lateral teeth on each blade,
except C, which has only eleven. In other valves examined, the number of the
lateral teeth in A and B, vary from nine in the smallest to thirteen in the
largest, valve C generally having one less. From the right posterior interam-
bulacrum, at the ambitus, in valves A and C (figs. 8, 9), height 0.26 mm.,
the blades are round at their upper ends, and about one third the length of
the base, while in two other valves B and C, 0.34 mm. in height (figs. 10, 11),
from towards the apical system, the blades are longer, and the bases broader
at the articulation surface. Another (fig: 12), valve B, height 0.32 mm. from
near one of the genital plates, has assumed the form of those on the actinal
side. All these pedicellariae came from the same specimen, 34 mm. long, from
Lord Howe Island, N. 8. Wales.

When the distance between the localities, and the difference in length of
the two specimens (one 34 mm. from N. 8. Wales; the other 19 mm. long, from
Fakarava Island) is considered, it is singular that the pedicellariae do not appar-
ently show any real differences (see figs. 13, 14, two valves, A and B, from the
right posterior interambulacrum of the latter). Attention should be called to
the slenderness of the valves (Pl. 22, figs. 15, 16), in a specimen 30 mm. long,
from Barbados, when compared with a valve of a 4 mm. specimen from Jamaica,
(Pl. 23, fig. 5); in the latter it is nearly triangular, with a minute blade and
rounded base. This difference might be considered important if another valve
(Pl. 23, fig. 6), from the same part of the ambitus and from the same Jamaican
specimen was not shaped like those from Lord Howe Island and if it was not

also unlike two valves (figs. 7, 8), in a specimen 5 mm. long, from Jamaica.

ECHINONEUS CYCLOSTOMUS. 57

The articular loop in valve A is short, straight, and generally has two
foramina; in valve B, the loop is prolonged either at the right or left side (Pl. 22,
figs. 4, 14), with a single foramen, while in valve C, the articulation surface slopes
downward, and the loop is rudimentary.

The triphyllous pedicellariae were found only in the Jamaican specimens
(Pl. 23, figs. 16, 17), and mostly in the ambulacra near the actinostome. Even
in the adult specimens they are very small, 0.04 mm. in height; the bilobed blade
constitutes the largest part of the valve.

A comparison of the height of the pedicellariae to the length of the test
from which they were taken, shows that in young specimens they are propor-
tionally larger than in the adult. Where a tridentate pedicellaria is 0.13 mm.
in height on a 4 mm. specimen, it is only 0.51 mm. from a test 34 mm. long.

The stalk of the pedicellariae differ in form on different parts of the test.
One stalk (Pl. 26, fig. 31), of an ophicephalous pedicellaria, near the actino-
stome, from a specimen 18 mm. long from Makemo Islands, with its long rod,
ending in a head, is similar in form to one of the same order from the actino-
stome of an adult specimen (PI. 27, fig. 36), from Jamaica. In a specimen 34
mm., from Lord Howe Island, on the abactinal side towards the apex (PI. 26,
fig. 19), the stalk is thicker, and without a head, corresponding to one (PI. 27,
fig. 13), on the abactinal side of a specimen 23 mm. long, from Fakarava Island.

The stalks of the globiferous pedicellariae have peculiar processes, similar
to those of some spatangoids, as figured by Mortensen ‘‘Ingolf’’ Exped. Ech.,
pt. 2, pl. 17, 18). Otherwise they show little diversity, though one (PI. 26,
fig. 17) from near the apical system of a Pacific specimen, 34 mm. long, is more
solid than some others. The latter are shown on Pl. 27, one (fig. 24) from the
abactinal surface of a specimen from Barbados, 30 mm. long, and another (fig. 44)

from a Jamaican specimen only 4 mm, long.

THE SPICULES OF THE TUBE-FEET.
Plate 28, figs. 1-14.

No special difference was found in the tube-feet (Pl. 28, figs. 1-14), though
a large number of specimens from the Pacific and also the West Indies were
studied. They all agree in having a disk composed of three plates, but the
number may vary, as Lovén has shown (Pourtalesia, Pl. 11, fig. 117). In
some the periphery of the plates is lobed (PI. 28, figs. 5, 6, 13), but usually it
has an irregular ragged outline, as seen in Pl. 28, figs. 8, 9, 12, 14; figs. 8 and 9

DS TROPICAL PACIFIC ECHINI.

are from West Indian specimens, figs. 72 and 74 from specimens taken in the
Pacific.

At the smaller inner end, the plate (PI. 28, figs. 5, 6, 12) is prolonged slightly
beyond the adjoining surface in some of the Makemo and Jamaican specimens.
This is quite different from what is seen in a Barbados specimen, where the pro-
jection can easily be recognized, though placed in a reéntrant curve (Pl. 28,
figs. 8, 9). In another specimen from Fakarava Island the inner end of the
plate (PI. 28, fig. 14) is almost straight.

Close to the base of the disk on the lower side there is a set of two or more
layers of yoke-shaped spicules (Pl. 28, figs. 2, 3, 7); these are nearly straight with
a few small perforations on the inner side of the spicule. The tube-feet on the
actinal, and on the greater part of abactinal side, seem to be without any other
spicules, but in some of the tube-feet near the ocular plates a number of slender
rods (fig. 10) were found; the disk plates were only rudimentary.

The changes in the appearance of the disk may be due as much to their
position on the test as to growth, as may be seen in three Jamaican specimens.
In a specimen 25 mm. long the tube-feet of the actinal side, near the mouth
(fig. 5) with disks 0.22 mm. across, are very different from those near the apical
system (fig. 6) with disks only 0.14 mm. wide. But-in much younger specimens,
the first formed tube-feet (fig. 4) which are found close to the mouth, are similar
to the newly formed ones near the ocular plate. Apparently the difference
between figs. 17, 12, from the actinal side of the test, and fig. 73, from near the

ocular plate, in the specimen from Makemo, is due to difference in age.

THe PERIPODIA.
Plate 28, figs. 15-24.

A comparison of the peripodia in a number of specimens, both young and
adult, from various localities, does not reveal any reliable specific character,
as the shape of the peripodium changes in form, size, and position on the different
plates.

Of four peripodia (Pl. 28, figs. 15-18), from a specimen 34 mm. long, from
Lord Howe Island, the first one at the edge of the actinostome (fig. 15), is singly
perforated, and placed vertically on the plate. The fifth from the actinostome,
(fig. 16), with its great horizontal perforations, is the largest; the smallest is
attached to the ambitus, and is placed diagonally on the outer part of the plate.

These and one of the youngest peripodia near the ocular plate, with its oval

ECHINONEUS CYCLOSTOMUS. 59

form and large perforations illustrate the variation that obtains in the same
specimen.

The open rectangular shape of the first pore in the edge of the actinostome,
in a specimen 37 mm. long, from Mauritius, while not of common occurrence, is
far from exceptional in specimens from other localities.

Any peripodium would have sufficed to show the variation in shape, but for
uniformity the fifth one (PI. 28, figs. 16, 20, 22-24), in the odd anterior ambula-
crum of five adult specimens from the Indian, Pacific, and West Indian regions
was selected.

THE SPINES.
Plate 26, figs. 1-15, 20-29; Plate 27, figs. 1-11, 14-22, 25-34, 37-42.

There are only two kinds of spines; one on the primary tubercles, the other
on the miliaries (Pl. 26, figs. 1-15, 20-29; Pl. 27, figs. 1-11, 14-22, 25-34, 37-42).
Those of the primaries are without serrations, some of them on the actinal side,

especially those near the oral and anal systems in adult specimens, reach a length
of three millimetres or so. The radioles on the abactinal side become stouter
with either a blunt or pointed end, and gradually diminish in length until in the
apical system they measure less than half a millimetre, and on the madreporic
plate not quite one fourth of one.

I have been unable to find any difference between the radioles of specimens
from the Pacific or the West Indian regions, excepting a slight individual
variation. The base on the longer spines agrees in being higher at one side and
thus giving the milled ring a sloping line when seen in profile. The sections
of these spines given on Pls. 26, 27, show either about nine or twelve rods in each;
exceptionally one or more of these rods (as seen in Pl. 26, figs. 2, 3; Pl. 27,
figs. 8, 9, 30, 38, 40), is serrated near the base, or for the whole length. The
various forms in the outline of the sectional figures are due to the shape of the
rods, which in some spines are semicylindrical, while in others they are much
more prominent and deeply separated from each other.

Radioles of the same length, and from the same plate may differ noticeably
from each other according as to whether they have a pointed or a rounded tip.
This is shown by two spines (PI. 26, figs. 6, 7) from the ambitus, left anterior inter-
ambulacrum, of a Pacific specimen, 34 mm. long. A similar difference is also
easily seen by comparing two spines from a Barbados specimen, 30 mm. long;
one (PI. 27, fig. 18) from the ambitus, right anterior interambulacrum; the other
(Pl. 27, fig. 17) from the odd posterior interambulacrum near the anal system.

60 TROPICAL PACIFIC ECHINI.

The spines of the miliaries are serrated, smaller in size and of even diameter
up to the distal end where they thicken, and each rod ends in a sharp point.
Those found on or close to the actinostome are nearly one millimetre in length,
and diminish until in the apical system they are very minute. There are some
even on the anal system. ‘The only other form seen was in a Fakarava Island
specimen (Pl. 27, figs. 1, 2), where near the actinostome a few of them are lance-
olate. The serrations on these spines from near the actinostome, frequently stop
short of the distal end in specimens from the Barbados (PI. 27, fig. 15) and Jamaica
(Pl. 27, fig. 25).

THE LANTERN AND AURICLES.
Plate 11, figs. 1, 2, 7, 8; Plate 12.

Of the various specimens brought from Port Antonio, Jamaica, a small
number were nearly, or but a little over, five millimetres in length; only four,
provided with a masticatory apparatus, were under this measurement. Consid-
ering that they had been a few days in alcohol, when the preparations were made,
they showed the various parts, including the pigmented sack that holds the
lantern (PI. 11, figs. 7, 2), very well. The lower end of this sack is probably
joined to the buccal membrane by a small neck; it contains a few caleareous
particles close to the teeth (Pl. 11, fig. 4). In just what manner this sack passes
the pentagonal muscular band of the summit of the lantern, and whether it is
connected with the oesophagus which goes through its centre where the com-
passes meet, could not be ascertained, as the diameter of the lantern was only
1.24 mm. and too fragile for dissection. The calcareous parts of the whole
apparatus are fairly solid, and not quite so delicate as the valves of the pedi-
cellariae. To each of the primordial interambulacral plates are attached a pair
of strong muscles (PI. 11, fig. 2), each with two branches at the upper end, one
of which is fastened to the compass, the other apparently to the brace. The
lower end of each half pyramid is also connected by two muscles to the rudimen-
tary auricle, and its ambulacral plate. After being denuded of their spines, the
smallest specimens having a lantern, were only 3.70 mm. in length (Pl. 11,
fig. 1), and the largest 4.25; in the latter (PI. 11, fig. 8), the volume of the dental
apparatus filled about one sixth of the space inside the test. The next available
size was 5.16 mm. in length (Pl. 11, fig. 9), and lacked not only the masticatory
apparatus, but the auricles also (Pl. 11, fig. 10)... It seems very unlikely that

* The statement (Amer. journ. sci., 1909, ser. 4, 28, p. 490) that the small auricles are present is
erroneous.

ECHINONEUS CYCLOSTOMUS. 61

it was shed, or liberated spontaneously. A resorption similar to that which
occurs in some parts of the test, appears more probable. In what manner the
oesophagus follows this change, and from a tiny tube inserted at the centre of
the pyramids, becomes funnel-shaped at its lower end and fastened to, or near
the pentagonal nerve and water-vascular canal, which remains permanent
on the buccal membrane, is a matter of conjecture.

The auricles are disconnected, minute and flattened to the ambulacral
plate (Pl. 11, figs. 5, 6). The largest part of their surface is covered by a mus-
cular attachment. Their resorption is probably contemporary with the dental
parts.

The pyramids (PI. 12, figs. 4-8), have deep foramina, a little over one third
of the height, are slightly concave on the inside, and somewhat keeled on the
outside parallel to the tooth. The adjacent edges are thin, and the corrugations
absent. The outline, narrow at the summit, and the lower tapering end, differ
considerably from the figure of Discoidea, given by Hawkins (Geol. Mag.,
new ser. Decade V. April, 1909, 6, p. 148-152, pl.6). The compass (Pl. 12,
figs. 11, a. b), is distinctly articulated, and when seen in profile curves at the
outer end.

The scapula-shaped epiphyses without being united to the pyramid (PI. 12,
figs. 1, 12 a. b), follow the brace horizontally, and are held in place by connecting
tissue; this could have been seen (PI. 1, fig. 7), if its minuteness had not pre-
vented removal of the membrane, which would have displaced the parts. The
braces do not show any special peculiarity in form.

Seen in profile the strong tooth (PI. 12, figs. 9 a. b. ¢), is distinetly curved

with a high keel on the inner face and a shallow groove on the outer.

THe ALIMENTARY CANAL.
Plates 8-10, Plate 11, figs. 8, 9.

Although the Jamaican specimens were in very good condition for examina-
tion, having been in alcohol only a few days, still several important points of
anatomical detail remain for future study on living specimens, and the figures
given are limited to the alimentary canal, and the associated reproductive organs.
The oesophagus rises vertically from the buccal membrane in a thin transparent
funnel-shaped tissue, which tapers quickly into a tiny tube (PI. 10, fig. 5), and
extends nearly half the height of the test, where close to the insertion of the
actinal intestinal appendage it enters the actinal loops of the alimentary canal

62 TROPICAL PACIFIC ECHINI.

(Pl. 10, figs. 1, 2, 4, 5), at a sharp angle. In the young, the oesophagus nearly
reaches the madreporic plate, with the axial organ on its right side (PI. 10,
fig. 3, Pl. 11, figs. 8, 9). It is held in place with the flat almond-shaped actinal
intestinal appendage by a mesentery which is fastened to the abactinal part of
the left anterior interambulacrum, close to the odd anterior ambulacrum; this
mesentery divides the upper anterior cavity of the test into two open chambers
(Pl. 10, fig. 4). The free vertical edge of this mesentery is slightly folded near
the genital ducts, broadening as it comes to the buccal membrane where it is
apparently connected with the nerve-ring by what may be the lower part of the
axial organ (PI. 10, fig. 5). A nerve ascends along the free edge of the mesentery
and shortly before reaching the apex, connects with the axial organ.

In young specimens, test without spines, 5 mm. long (PI. 9, figs. 4, 5, 6), the
general shape of the alimentary canal is nearly like that of the adult. The actinal
loop is broad where the oesophagus and actinal intestinal appendage are inserted
(Pl. 8, figs. 3-5, Pl. 9, figs. 7, 2), and continues so until in its curve backward
and to the right, it passes the right posterior ambulacrum. There it gradually
narrows, until it reaches the anterior margin of the right anterior interambulacrum
where it curves abruptly upward and becomes the abactinal loop, following the
ambitus on the right side of the test. When it reaches the odd posterior inter-
ambulacrum, it broadens and has a reéntering curve for passing the rectum
(Pl. 8, figs. 3-5), in front of the median line; its outer edge being closer to the
test, than that of the actinal loop. In the left anterior interambulacrum, the
abactinal loop suddenly tapers (Pl. 8, figs. 4, 5, Pl. 9, fig. 2), passes upward
close under the reproductive organs, and becomes tubular. It is held by mesen-
teries to the abactinal median line of the odd posterior interambulacrum clear
to its end at the anal plastron. Posterior to the oesophagus from the buccal
membrane (PI. 10, fig. 5), there rises a narrow mesentery which soon turns a
half spiral, with its broadest surface attached to the inner edge of the left half
of the actinal loop, and to the actinal intestinal appendage; while the narrow
part is fastened to the inner edge of the right half of the actinal loop (PI. 8,
fig. 3, Pl. 9, fig. 1), as far as the odd anterior ambulacrum. Another mesentery
is attached in a similar way to the abactinal loop of the alimentary canal (PI. 10,
fig. 4), but is connected with some of the plates of the apical system.

Close to the left anterior inner side of the actinal loop, on the mesentery
is a brownish pigmented band (PI. 8, fig. 3; Pl. 9, fig. 7), leading from the inser-
tion of the oesophagus, and extending posteriorly. This is probably the acces-

sory intestine.

MICROPETALON PURPUREUM. 63

The tissue of the intestines is generally highly pigmented and smooth,
but sometimes contracted with peculiar regularity into surface folds, as seen
in Pl. 10, fig. 9. The rectum (PI. 10, fig. 70), in all the specimens examined was
contracted lengthwise in long irregular creases.

Satisfactory figures of the nervous and water-vascular systems (Pl. 10,
fig. 7), were not obtained, though the ampullae appear to be bilobed, twice as
long as wide, and pigmented (PI. 10, fig. 8).

The reproductive organs (PI. 8, fig. 2; Pl. 10, figs. 7, 2), are lacking in the

posterior interambulacrum, but show no special peculiarity in their structure.

Micropetalon purpureum A. Acassiz and H. L. Ciark.

Plates 29-31.

Unfortunately there is only a single specimen of this species which, although
17 mm. in length may not be fully adult. The general aspect and some of the
details are those of Echinonéus. The broad ovoid ambitus, large triangular
oral, and oblique anal apertures, recall the specimen of Echinonéus, 16 mm.
long, from Florida (PI. 5, fig. 17).

On comparison with a young Echinonéus, 4.40 mm. long, (Pl. 3, figs. 1, 2,
Pl. 13, fig. 7, Pl. 14, figs. 7, 2, Pl. 15, fig. 7), from Makemo Island, I find the test
frail in both, the ambulacra flattened, and the breadth of the interambulacra
at the ambitus in the bivium broader than in the trivium. In Micropetalon
the adoral end of the anal opening inclines towards the left posterior ambula-
crum, but this may be an individual peculiarity. The size and grouping of
the plates on the anal plastron are precisely similar to the same in the young
Echinonéus, but being further advanced in age, the anal system has acquired
on each side, two additional interradial plates. The oral membrane in each is
overlaid with minute caleareous plates, radiating towards the centre. Of the
genital plates, three are of about the same size, while the left anterior is smaller.
In Micropetalon the genital pores are present, which is not the case in the young
Echinonéus. The ocular plates in the bivium are in contact in Micropetalon
exactly as in the Echinonéus from Makemo.

The primary tubercles are comparatively few in number, and well separated,
being grouped, beginning at about the fourth plate from the actinal system, in
two horizontal rows on each plate, or diagonally over the test; each of the last
four or more of the abactinal interambulacral plates has only one of these tubercles.

Like the young Echinonéus (Pl. 24, figs. 1, 2), Micropetalon has only three
series of primary tubercles in the odd anterior ambulacrum. The first tubercle

64 TROPICAL PACIFIC ECHINI.

of the inner series in Echinonéus usually appears first just in front of the fourth
tubercle (from the edge of the actinal system) of the outer row; but in Micro-
petalon it is in front of the second. The mamelon is without perforation, the
boss slightly raised, and the scrobicular circle indistinct. Of glassy tubercles
there are only a few, mostly near the abactinal system.

Upon comparing the arrangement of the coronal plates in a specimen of
Echinonéus, 5.90 mm. long, from Jamiaca (PI. 6, fig. 1), with that of Micropeta-
lon (Pl. 30), I find a notable agreement; and considering the difference in size,
it is remarkable that there are nearly the same number of plates in the radii of
both.

There were probably three sphaeridia in each ambulacrum, in Micropetalon;
those seen were pear-shaped. Of the pedicellariae I found only the ophicepha-
lous, and these show little diversity in form and reveal no special characters.
As in Echinonéus, a few spines near the actinal system have serrations which
do not continue fully up to the distal end, and the longer spines also vary in
having nine or more rods.

One of the notable points is the form of the spicules in the actinal tube-feet;
there are four disk plates in each, with yoke-shaped spicules at their inner mar-
gins, while the outer edge of the disk generally has a ring of slender spicules
slightly bent at both ends. At the ambitus and on the abactinal side near the
ocular plates the basal disk has diminished in diameter to about 0.11 mm. with
the four disk plates still less developed.

What may especially separate Micropetalon from Echinonéus, is the small
low boss of the primary tubercles, that leaves greater intermediary space; while
the absence of the thick glossy plates on the oral membrane and the flush
poriferous zone with the minute ambulacral pores at the ambitus’ suggest the
retention of juvenile characters. The largest pores are in the primordial ambula-
cral plates, and one or two of the succeeding plates, and are vertically placed;
the smallest are arranged diagonally at the ambitus, with a different form of
peripodium and of pore opening, which are, however, different from those on the
abactinal side towards the ocular plate where the pores are nearly horizontal.
The resemblance to Echinonéus and the difference from the adult of that genus
which the ambulacral pores of Micropetalon show, are well brought out in the
figures (compare PI. 28, figs. 15-18, Pl. 29, figs. 9-12).

One specimen of this species was taken during the 1902 cruise of the “‘ Alba-
tross” at Station 3847. Off Lae-o Ka Laan Light, Molokai, Hawaiian Islands,
N. 64° 30’, W. 23’. 23-24 fms. bottom of sand and stones.

These were overlooked when the specimen was first studied (Bulletin M. C. Z., 1907, 60, p. 251).

ECHINONEUS, MICROPETALON.

65

LIST OF SPECIMENS.’

Echinonéus cyclostomus LEsKE.

Number of | Length of test in milli-

Condition Data
specimens | metres |
4 | largest nearly 30 Dry Hawaiian Islands
8 13) 15; 16, 1982052252620 (ee Pacific ?, 1863. J. G. Anthony
4 | 13, 14, 15, 18 fe Kingsmills Islands, Gilbert Islands. A. Garrett
1 | 20 |) Kingsmills Islands
3 | largest about 40 sf Society Islands
7 | 4.40, 10, 12, 14, 15, 18,27 | Aleoholie | Makemo, Paumotu Islands, Oct. 21. ‘Alba-
tross” Exped. 1899-1900. U. S. Nat. Mus.
| (5), Mus. Comp. Zodl. (2)
5 | 11, 12, 13, 19, 23 | Fakarava Island, Paumotu Islands. Oct. 12,
1899. “ Albatross’? Exped. 1899-1900, U. 8.
} | Nat. Mus. (3) Mus. Comp. Zodl. (2)
4 | 6, 13, 14, 16 Dry | Easter Island, Chile. Dec. 1904, “Albatross”
| Exped. 1904-05. U.S. Nat. Mus. (3), Mus.
| Comp. Zoél. (1)
1 | 20 ss Australia
2 30, 34 lige ss Lord Howe Island, New South Wales (Littoral)
2 27.5, 28 | Aleoholie | Mauritius, Oct. 13, 1873. Nicholas Pike
2 36, 37 | Dry Mauritius
9 | 5, 8, 9, 11, 15, 26, 28, 29,31) Mauritius. Mrs. Luckock
7 Nile Ay ese Bourbon
1 i ot | Mujeres Island, Yucatan. W. Stimpson
1 16 | Aleoholie | Florida, Carysfort Reef. 1868, L. F. de Pourtalés
2 |20 Dry West Indies
2 | 17, 20 “ Cuba, 1859
1 } 11 Alcoholic | Havana, “Blake,” 1877-78
1 | 26 Dry | Jamaica, Hitchcock
144 | 3.70-28 | Aleoholie | Port Antonio, Jamaica. March, 1909, H. L.
| Clark. Mus. Comp. Zool., U. S. Nat. Mus.
29 «| 6-20 Dry | Port Antonio, Jamaica. March, 1909, H. L. Clark
2 |10,15 « Hayti
4 12, 14, 16, 18 s Antilles, 1859
1 14 fs St. Thomas
7 26, 30 | Aleoholic | Barbados (?) U. S. Eclipse Exp. to West Africa
| 1989. U.S. Nat. Mus.
Micropetalon purpureum A. AGcassiz and H. L. Cuark.
1 117 Dry Off Lae-o Ka Laan Light, Molokai, Hawaiian Is-

lands. ‘“‘Albatross’” Exped. 1902. U.S. Nat.

Mus.

‘ All the specimens are in the collections of the Museum of Comparative Zoélogy and the U. S.

National Museum.

66 TROPICAL PACIFIC ECHINI.

SYNONYMICAL LIST.

Ecurnonius Van Phelsum.
1774. Van Phelsum, Brief Zeelglen, p. 32.
E. cycLtostomus Leske.
1778. Leske, Addit. Klein, p. 109, pl. 37, fig. 4, 5.
1790. Gmelin, Syst. Nat., 1, pt. 6, p. 3183 (Echinus).
1816. Lamarck, Anim. sans Vert., 3, p. 18.
1819. Blainville, Dict. Sci. Nat., 14, p. 196.
1825. Gray, Thomson’s Ann. Phil., 10, p. 429 (Hchinanaus).
1834. Blainville, Actinologie, p. 212, pl. 16, fig. 5.
1835. Agassiz, Mém. Soc. Sci. Nat. Neuchatel, 1, p. 187.
1842. Desor, Agassiz’s Monog. Echin. Galérites, p. 43, pl. 6, fig. 13-15.
1847. Agassiz, Ann. Sci. Nat., ser. 3, 7, p. 143.

1855. Gray, Catal. Rec. Echin. Brit. Mus., p. 32.
1857. Desor, Synop. Echin. Fossiles, p. 197, pl. 27, fig. 1-3.
1862. Dujardin et Hupé, Echin., p. 545.

1872-73. A. Agassiz, Rev. Echini, p. 117, 550.

1874. Lovén, K. Svenska Veten. Akad. Handl., 11, no. 7, pl. 9, fig. 79-82.

1883. Loriol. Mém. Soe. Phys. Genéve, 28, no. 8, p. 38, pl. 5, f. 3-6.

1894. Anderson, Journ. Asiatic Soc. Bengal, 63, p. 194.

1895. Sluiter, Konin, Zoél. Genoot. Amsterdam, Bijdr. Dierkunde, afley.
1708) pies

1897. Egozcue y Cia, Bol. Com. Mapa Geol. Espafia, 22, p. 48, pl. 15,
fig. 5-9.

1899. Anderson, Rept. Marine Surv. India, 1898-99, p. 16.

1907. Mortensen, Danish Ingolf-Exped., 4, pt. 2, p. 184, 193.

1911. Westergren, Ante, p. 44.

E. ovalis Linné.

1753. Linné, Mus. Tessin, p. 114 (Echinus).

1758. Seba, Locup. Rerum Nat. Thes., 3, pl. 10, fig. 7, pl. 15, fig. 30, 33,
34. (Hchinus.)

1771. Knorr, Delic., pl. D. I., fig. 11 (Echinus).

E. minor Leske.

1778. Leske, Addit. Klein, p. 110, pl. 49, fig. 8, 9.

1834. Blainville, Actinologie, p. 212.

1842. Desor, Agassiz’s Monog. Echin. Galérites, p. 45, pl. 6, fig. 16.

ECHINONEUS CYCLOSTOMUS 67

1847. Agassiz, Ann. Sci. Nat., ser. 3, 7, p. 143.
1855. Gray, Catal. Rec. Echin. Brit. Mus., p. 32.
1862. Dujardin et Hupé, Echin., p. 545.
1866. Martens, Archiv f. Naturg., 32, bd. 1, p. 169.
E. semilunaris Gmelin.
1790. Gmelin, Syst. Nat., 1, pt. 6, p. 3184 (Hchinus).
1816. Lamarck, Anim. sans Vert., 3, p. 19.
1819. Blainville, Dict. Sci. Nat., 14, p. 196.
1835. Agassiz, Mém. Soe. Sci. Nat. Neuchatel, 1, p. 187.
1836. Milne Edwards, Cuvier’s Régne Anim., 10, p. 27, pl. 14, fig. 1
(Echinus).
1837. Des Moulins, Etudes, p. 340.
1864. Lutken, Bidrag Echin., p. 56.
1869. A. Agassiz, Bull. Mus. Comp. Zodl., 1, p. 267.
1872. A.-Agassiz, Rev. Echini, p. 118, 333.
1874. Lovén, K. Svenska Veten. Akad. Handl., 11, no. 7, pl. 9, fig. 83.
1881. Bell, Ann. Mag. Nat. Hist., ser. 5, 8, p. 437.
1883. Lovén, K. Svenska Veten. Akad. Handl., 19, no. 7, pl. 11, fig. 116,
117, pl. 12) fig. 132:
1893. Field, Univ. Cire. Johns Hopkins Univ., 11, p. 84.
1895. Sluiter, Konin, Zoél. Genoot. Amsterdam, Bijdr. Dierkunde, aflev.
17-18, p. 73.
1898. Clark, Univ. Cire. John Hopkins Univ. 18, p. 5.
1898. Clark, Ann. N. Y. Acad. Sci., 11, p. 412.
- 1899. Clark, Ann. N. Y. Acad. Sei., 12, p. 132.
1900. Lambert, Bull. Soc. Yonne, 53, p. 49.
1901. Clark, Proc. Bost. Soe. Nat. Hist., 29, p. 344.
1901. Verrill, Trans. Conn. Acad. Sci., 11, p. 37.
1907. Mortensen, Danish Ingolf-Exped., 4, pt. 2, p. 185, 186, 193.
1909. A. Agassiz, Amer. Journ. Sci., ser. 4, 28, p. 490, pl. 2.
E. gibbosus Lamarck.
1816. Lamarck, Anim. sans Vert., 3, p. 19.
1819. Blainville, Dict. Sci. Nat., 14, p. 196.
1835. Agassiz, Mém. Soe. Sci. Nat. Neuchatel, 1, p. 187.
1837. Des Moulins, Etude, p. 340.
1842. Desor, Agassiz’s Monog. Echin. Galérites, p. 46, pl. 6, fig. 4-6.
1855. Gray, Catal. Rec. Echin. Brit. Mus., p. 32.

68 TROPICAL PACIFIC ECHINI.

E. echinonea, Des Moulins.
1837. Des Moulins, Etudes, p. 246. (Galérites.)
E. serialis Desor.
1842. Desor, Agassiz’s Monog. Echin. Galérites, p. 48, pl. 6, fig. 10-12.
1847. Agassiz, Ann. Sci. Nat., ser. 3, 7, p. 143.
1855. Gray, Catal. Rec. Echin. Brit. Mus., p. 33.

1862. Dujardin et Hupé, Echin., p. 545.

=|

E. elegans Desor.
1842. Desor, Agassiz’s Monog. Echin. Galérites, p. 47, pl. 6, fig. 7-9.
1863. A. Agassiz, Bull. Mus. Comp. Zoél., 1, p. 25.
E. conformis Desor.
1842. Desor, Agassiz’s Monog. Echin. Galérites, p. 48, pl. 6, fig. 17-21.
1860. Brown, Klass. und Ord. Thier-reichs, 2, pl. 42, fig. 2.

7

#. cruciatus Agassiz.

1842. Agassiz, Monog. Echin. Galérites, p. 46, pl. 6, fig. 1-3.
1855. Gray, Catal. Ree. Echin. Brit. Mus., p. 33.

E. crassus Agassiz.

1847. Agassiz, Ann. Sci. Nat., ser. 3, 7, p. 143.

1855. Gray, Catal. Ree. Echin. Brit. Mus., p. 33.

1862. Dujardin et Hupé, Echin., p. 546.

1863. Michelin, Maillard’s Notes Réunion, 2, annexe A, p. 5, pl. 16, fig. 1.
E. ventricosus Agassiz.

1847. Agassiz, Ann. Sei. Nat., ser. 3, 7, p. 144.

1855. Gray, Catal. Ree. Echin. Brit. Mus., p. 33.

1862. Dujardin et Hupé, Echin., p. 546.
E. abnormalis Loriol.

1883. Loriol, Mém. Soe. Phys. Genéve, 28, no. 8, p. 41, pl. 5, fig. 2.
Micropetaton A. Agassiz and H. L. Clark.

1907. A. Agassiz and H. L. Clark, Bull. Mus. Comp. Zodl., 50, p. 251.
M. PURPUREUM A. Agassiz and H. L. Clark.

1907. A. Agassiz and H. L. Clark, Bull. Mus. Comp. Zoél. 50, p. 251.

1911. Westergren, Ante, p. 63.

EXPLANATION OF THE PLATES.

+

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PLATE 1.

1-2. Echinonéus cyclostomus Lrske.
1.— Seen from the abactinal side. Natural colors. 30
2.— Same in profile, showing the left anterior int era m

Port Antonio, Jamaica. H. L. Clark.
Twice natural size.

“ALBATROSS TROPICAL PACIFIC Ex. 1899-1900. EGHINONEUS PLATE 1.

AM Wesuergren del. B Meisel lit,

“

PLATE 2.

1-7. Echinonéus cyclostomus Leske.

1.— Actinal side of alcoholic specimen, measuring 30 mm. long. Barbados (?).

2.— The same from the abactinal side.

3.— The same in profile, facing the left anterior and the left posterior interrad.

4.— Abactinal side of alcoholic specimen, measuring 10 mm. long. Makemo Island, Paumotu Islands.
5.— The same from the actinal side.

6.— The same in profile facing the left anterior and the left posterior interrad.

7.— Actinal side of alcoholic specimen, measuring 6 mm. long. Makemo Island.

“ALBATROSS TROPIGAL PAGIFIG Ex. 1899-1900. EGHINONEUS. PLATE 2.

A.M. Westeremn del B. Meisel lith
Meisel ith

PLATE 3. -

1-5. Echinonéus cyclostomus Li

1.— Actinal side of alcoholic specimen measuring 4.40 mm.

2.— The same from the abactinal side. 7
3.— Actinal side of dry specimen measuring 27 mm
4.— The same from the abactinal side.

GHINONEUS PLATE 3.

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ALBATROSS’ TROPIGAL PAGIFIG Ex. 1899-1900.

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PLATE 4.

1-25. Echinonéus cyclostomus LEsKE.

Outlines of test.

1.— Actinal side of specimen measuring 37 mm. long. Mauritius.
2.— Actinal side of specimen measuring 30 mm. long. Mauritius.
3.— Actinal side of specimen measuring 29 mm. long. Bourbon.
4.— The same in profile facing the left anterior and the left posterior interrad.
5.— End view of same, presenting odd anterior ambulacrum.
6.— Actinal side of specimen measuring 27 mm. long. Pacifie (2).
7.— Actinal side of specimen measuring 19 mm. long. Pacifie (?).
8.— Actinal side of specimen measuring 27 mm. long. Makemo Island. Paumotu Islands.
9.— The same in profile.
10.— End view of same.
11.— Actinal side of specimen measuring 17 mm. long. Bourbon.
12.— Actinal side of specimen measuring 18 mm. long. Kingsmills Island.
13.— The same in profile.
14.— End view of same. i
15.— Actinal side of specimen measuring 13 mm. long. Gilbert Islands.
16.— The same in profile.
17.— End view of same.
18.— Actinal side of specimen measuring 14 mm. long. Gilbert Islands.
19.— Actinal side of specimen measuring 7 mm. long. Mujeres Island, Yucatan.
-20.— Actinal side of specimen, measuring 19 mm. long. Pacific (2).
21.— The same in profile.
22.— End view of same.
23.— Actinal side of specimen measuring 17 mm. long. Cuba.
24.— The same in profile.
25.— Actinal side of specimen measuring 5.5 mm. long. Mauritius.

All the profile views show the left anterior and the left posterior interrad.

The end views show odd anterior ambulacrum.

The enlargement is about once natural size.

Figures 8-10, are from alcoholic specimens; the other figures are from dry specimens.

ALBATROSS’ TROPIGAL PACIFIG Ex. 1899-1900,

PR 2

AM Westereren del.

EGHINONEUS PLATE 4.

B Meisel lith.

PLATE 4.

1-25. Echinonéus cyclostomus LEsKE.

Outlines of test.

1.— Actinal side of specimen measuring 37 mm. long. Mauritius.
2.— Actinal side of specimen measuring 30 mm. long. Mauritius.
3.— Actinal side of specimen measuring 29 mm. long. Bourbon.
4.— The same in profile facing the left anterior and the left posterior interrad.
5.— End view of same, presenting odd anterior ambulacrum.
6.— Actinal side of specimen measuring 27 mm. long. Pacific (?).
7.— Actinal side of specimen measuring 19 mm. long. Pacific (?).
8.— Actinal side of specimen measuring 27 mm. long. Makemo Island. Paumotu Islands.
9.— The same in profile.
10.— End view of same.
11.— Actinal side of specimen measuring 17 mm. long. Bourbon.
12.— Actinal side of specimen measuring 18 mm. long. Kingsmills Island.
13.— The same in profile.
14.— End view of same.
15.— Actinal side of specimen measuring 13 mm. long. Gilbert Islands.
16.— The same in profile.
17.— End view of same.
18.— Actinal side of specimen measuring 14 mm. long. Gilbert Islands.
19.— Actinal side of specimen measuring 7 mm. long. Mujeres Island, Yucatan.
.20.— Actinal side of specimen, measuring 19 mm. long. Pacific (?).
21.— The same in profile.
22.— End view of same.
23.— Actinal side of specimen measuring 17 mm. long. Cuba.
24.— The same in profile.
25,— Aetinal side of specimen measuring 5.5 mm. long. Mauritius.

All the profile views show the left anterior and the left posterior interrad.

The end views show odd anterior ambulacrum.

The enlargement is about once natural size.

Figures 8-10, are from alcoholic specimens; the other figures are from dry specimens.

ALBATROSS’ TROPIGAL PAGIFIG EX. 1899-1900. EGHINONEUS PLATE 4:
: 8 16 15

‘)

AM Westersten del. B.Meisel lth.

-

PLATE 5.

PLATE 6.

1-17. Echinonéus cyclostomus LEsKE.

1-10, 12-17. Actinal side of test. 11. Abactinal side of test.

1.— Specimen, including spines, measuring 30 mm. long. Lord Howe Island.
2.— Specimen measuring 34 mm. long. Lord Howe Island.

3.— Specimen measuring 27.5 mm. long. Mauritius.

4.— Specimen measuring 30 mm. long. Mauritius.

5.— Specimen measuring 9 mm. long. Mauritius.

6.— Specimen measuring 27 mm. long. Makemo Island, Paumotu Islands.
7.— Specimen measuring 19 mm. long. Pacifie (?).

8.— Specimen measuring 20mm. long. Pacifie (?).

9.— Specimen measuring 23 mm. long. Pacifie (?).
10.— Specimen measuring 27 mm. long. Pacifie (?).
11.— Abactinal side of a specimen measuring 20 mm. long. Cuba.
12.— Specimen measuring 6 mm. long. Port Antonio, Jamaica.

13.— Specimen measuring 9 mm. long. Jamaica.

14.— Specimen measuring 10 mm. Jong. Jamaica.

15.— Specimen measuring 16 mm. long. Jamaica.

16.— Specimen measuring 22 mm. long. Jamaica.

17.— Specimen measuring 16 mm. long. Florida.

All the figures are enlarged once the natural size.
Figures 1, 2, 4, 5, 7-11 are from dry specimens; the other figures are from alcoholic specimens.

10

PLATE 6. ‘S

1-8. Echinonéus cycloarees LESKE.

1.— Development of the coronal plates, seen from interior of an alcoholic specimen
measuring 5.90 mm. long. Jamaica.

2.— Bivium and odd posterior interambulacrum, seen from interior of a specimen measurin|
long. Jamaica. -

3.— The same, from a specimen measuring 6 mm. long. Jamaica. :

4.— The same from a specimen measuring 14mm. long. Jamaica. ~

5.— The same from a specimen measuring 22 mm. long. Jamaica.

6.— The same from a specimen measuring 25 mm. long. Jamaica.

7.— Bivium and odd posterior interambulacrum, seen from interior of :
long. Makemo Island, Paumotu Islands. :

8.— The same from a specimen measuring 27 mm. =

larger scale.

EGHINONEUS PLATE 6.

B Meisel lith.

PLATES. {

Echinonéus cyclostomus LESKE.

Arrangement of the coronal plates, seen from inside of a dry specimen
Mauritius.

B.Meisel lith.

EGHINONEUS PLATE 7.

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“ALBATROSS TROPIGAL PAGIFIG Ex. 1899-1900.~

PLATE 8.

1-5. Echinonéus cyclostomus LEske.

1.— Intestine in place, seen from below. Specimen measuring 26 mm. long. =

2.— Reproductive organs and alimentary canal, seen from above, free of its test, which meas u
long. :

3.— Alimentary canal, from actinal side. Pr

4.— Abactinal loop of the alimentary canal. Reproductive organs removed.

5.— Alimentary canal, actinal side. Intestinal appendage and part of actinal loop turn
curve of abactinal loop to the anal system.

The same specimen was used for figures 2-5.
Port Antonio, Jamaica, H. L. Clark.

EGHINONEUS PLATE 8.

“ALBATROSS TROPICAL PAGIFIG Ex. 1899-1900.

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PLATE 9.

1-6. Echinonéus cyclostomus LEsKE.

1.— Anterior part of actinal loop of the alimentary canal with mesentery, showing the actinal intestinal
appendage, oesophagus, madreporic tube, and termination of the genital ducts. Test with
spines measuring 23 mm. long.

2.— The same as above, seen from abactinal side.

3.— Intestinal appendage with intestine cut, exposing insertion of its neck. Same specimen as Figures
1-2.

4.— Intestine in place, seen from below. Test without spines measuring 5 mm. long.

5.— The same seen from below free from the test.

6.— The same seen from above.

go. generative organ.

ia. actinal intestinal appendage.
m. tniadreporic tube.
oes. oesophagus.

Port Antonio, Jamaica, H. L. Clark.

EGHINONEUS PLATE 9

“ALBATROSS TROPIGAL PACIFIG Ex. 1899-1900.

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AM Westeréren del

PLATE 10.

1-10. Echinonéus cyclostomus LEskKe.

1.— Alimentary canal, madreporic tube, and reproductive organs, seen from right side, with both
sides of test removed. Specimen with spines measured 22 mm. long.
2.— The same seen from left side.
3.— Actinal part of intestine, actinal intestinal appendage, oesophagus, and madreporic tube removed
from test, which without spines measured 4.19 mm. long.
4.— Longitudinal section of anterior end of test, showing appendage of alimentary canal, oesophagus,
and madreporic tube, held in place by mesenteries. Test with spines measured 22 mm. long.
5.— Profile of oesophagus, madreporie tube, and genital ducts, showing folding of edge of mesentery.
Specimen with spines measured 21 mm. long.
6.— Axial organ with mesentery laid back, showing nerve along outside edge. Same individual as
Figure 5. :
7.— Oral system with surrounding coronal plates, seen from interior, with pentagonal and radial
nerves, and water-vascular canals, showing oesophagus fastened to inner margin of pentagon.
Dissected to show mouth in centre of buccal membrane. Test without spines measured 21 mm.
long. 7
8.— Nerve with radial canal, and two ampullae, from odd anterior ambulacrum, actinal side, midway
actinal system, and ambitus. Test without spines measuring 21 mm. long.
9.— Mesentery and outside edge of intestine, showing surface folds. Test without spines measuring
21 mm. long.
10.— Outside edge of abactinal alimentary canal with mesentery. Test with spines measuring 22 mm.
long.

Port Antonio, Jamaica, H. L. Clark.

“ALBATROSS TROPIGAL PAGIFIG Ex. 1899-1900. GHINONEUS PLATE 10.

A.M Westersren del B.Meis

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PLATE 11.

1-10. Echinonéus cyclostomus LESKE.

1.— Transverse section, showing actinal floor and lantern in position. Test without spines measuring

3.70 mm. long.
2.— Lantern in natural position, from same specimen as Figure 1, showing oesophagus, compasses,
Diameter of actinostome 1.35 mm. and of lantern 1.24 mm. long.

and various muscles.
Test without spines

3.— Oral and part of anal system, showing gills, tentacles, and sphaeridia.
measuring 4.19 mm. long.

4.— First spicules round the teeth on the buccal membrane, seen from interior. Same specimen as
Figures 1, 2, and 3.

5 — Interior view of actinal system with the rudimentary auricles.
Specimen without spines measuring 4.19 mm. long.

6.— Odd anterior ambulacrum, interior view with auricles, enlargement of same specimen as Figure 5.

7.— Centre of oral system expanded, showing tips of teeth. Test without spines measuring 4.10 mm.

Diameter of actinostome 1.26 mm.

long.
8.— Profile longitudinal section exposing lantern, madreporic tube, and right side of alimentary canal.

Test without spines measuring 4.25 mm. long.
9.— Profile longitudinal section, lantern resorbed, with view of oesophagus and right side of ali-

mentary canal. Test without spines measuring 5.16 mm. long.
10.— Actinostome interior view, auricles resorbed, length of mouth aperture 1.18 mm, Same specimen

as Figure 9.

Port Antonio, Jamaica, H. L. Clark,

“CHINONEUS PLATE Il.

=
&£

ALBATROSS TROPIGAL PAGIFIG Ex. 1899-1900

AM Westerren del

PLATE 12.

1-12. Echinonéus cyclostomus Leske.

1.— Lantern seen from above, measuring 1.30 mm. in diameter.
2.— The same seen from below.
3.— The same in profile, height 0.75 mm.
4.— Pyramid and tooth, seen from exterior, length 0.85 mm.
5.— The same seen from interior.
6.— Half of same pyramid, without tooth, seen from exterior.
7.— The same seen from interior. =
8.— Pyramid with tooth, same as Figure 4, seen from above.
9.— Grooved tooth, b. seen in profile, c. dorsal view, length 0.62 mm.
-10.— The brace; a. seen from above with epiphysis on one side, b. the same from belo
0.44 mm. j
11.— Compass; a. seen from above, b. the same in profile, length 0.62 mm. long.
12.— Epiphysis; a. exterior view, b. interior view, length 0.44 mm.

All the figures are from a specimen without spines measuring 4.19 mm.
Port Antonio, Jamaica, H. L. Clark,

“ALBATROSS TROPIGAL PAGIFIG Ex. 1899-1900. EGHINONEUS PLATE 12.

AM. r
Westersten del B. Meisel lith

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PLATE 13.

1-6. Echinonéus cyclostomus Leske. t

1.— Interior view of actinal side, from alcoholic specimen, measuring 4.40 mm. long. Makem
Paumotu_ Islands. ; : 7
2.— Actinal side seen from interior. Test measuring 27 mm. long. Makemo Island.
3.— Odd anterior ambulacrum with part of the right and left anterior interradial plates, :
actinal system, seen from interior. , ¥ ;
4.— Interior view of median interambulacral suture in right posterier interambulac:
stome, showing overlapping of plates.
5.— Odd anterior ambulacrum, near ambitus, actinal side, seen from interior.
6.— Ocular and abactinal ambulacral plates of odd anterior ambulacrum, interior v

Figures 3-6 from a dry specimen, measuring 37 mm. long. Mauritius.
The enlargement is identical in Figures 3, 5, 6.

“ALBATROSS [ROPIGAL PACIFIG EX. 1899-1900. EGHINONEUS PLATE 13.

2

evar ,
A.M Westersren de]
s B. Meisel lith

. PLATE 14. .

1-7. Echinonéus cyclostomus LEeskE.

Abactinal system. < ah, .

1.— Exterior view. Alcoholic specimen denuded of its spines measuring 440 mm.
Island, Paumotu Islands. r :
2.— The same, interior view. R _.
3.— Interior view. Alcoholic specimen, test without spines measuring 4.19 mm. long.
Jamaica. i. e :
4.— Interior view. Alcoholic specimen measuring 12.5 mm. long. Jamaica. —
5.— Exterior view. Dry specimen, without spines measuring 26 mm. long. Pacif
6.— Exterior view. Dry specimen, without spines measuring 27 mm. long. -
7.— Interior view. Alcoholic specimen measuring 27 mm. long. Makemo I

The enlargement of Figures 5-7, is the same, the others are not identical.

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PLATE 15.

1-12. Echinonéus cyclostomus LeEsker.

Oral and anal systems.

1.— Alcoholic specimen from Makemo Island, Paumotu Islands, measuring 4.40 mm. long.
2.— Alcoholic specimen from Makemo Island, measuring 27 mm. long.
3.— Dry specimen from Lord Howe Island, measuring 30 mm. long.
4.— Dry specimen from Lord Howe Island, measuring 34 mm. long.
5.— Dry specimen from Mauritius, measuring 27 mm. long.
6.— Alcoholic specimen from Mauritius, measuring 27.5 mm. long.
7.— Anal system of dry specimen from Bourbon, measuring 29 mm. long.
8.— Oral and anal system of alcoholic specimen from Port Antonio, Jamaica, measuring 6 mim. long. —
9.— Anal system of alcoholic specimen from Jamaica, measuring 10 mm. long.
10.— Oral and anal system of alcoholic specimen from Jamaica, measuring 24 mm. long.
11.— Anal system of alcoholic specimen from Florida, measuring 16 mm. long.
12.— Anal system of alcoholic specimen from Barbados (?) 26 mm. long.

In all the figures the distance between the two apertures, is in natural proportion.
Figure 1 is larger proportionately. Figures 8, 9. are of the same magnification. The
magnified equally excepting figures 3-4 which are slightly larger. f=

THIS.

{INONEUS P.

Giny
EGON

1899-1900.

G EX.

1
it

1

BATROSS TROPIGAL PAG

L

B. Meisel lith

PLATE 16.

1-14. Echinonéus cyclostomus LEskKE.

Sphaeridia.

1-4— Aleoholic specimen, test measuring 12 mm. long, from Fakarava Island, Paumotu Islands.
1.— From right anterior ambulacrum, height 0.13 mm.
2.— From odd anterior ambulacrum, height 0.13 mm.
3.— From left anterior ambulacrum, height 0.12 mm.
4— From left posterior ambulacrum, height 0.13 mm.

5-7.— Dry specimen, test measuring 34 mm., 8, test measuring 30 mm. long, from Lord Howe Island.
5.— Both from odd anterior ambulacrum, height 0.16 mm. .
6.— From left anterior ambulacrum, height 0.10 mm.
7.— From left posterior ambulacrum, height 0.16 mm.
8.— Both from right anterior ambulacrum, height 0.18 mm.

9-14.— Aleoholie specimen, test measuring 1S mm., 13-14, test measuring 10 mm. long, from Makemo
Island, Paumotu Islands.

9.— From right posterior ambulacrum, height 0.13 mm.
10.— From right anterior ambulacrum, height 0.14 mm.
11.— From odd anterior ambulacrum, height 0.15 mm.
12.— Both from left posterior ambulacrum, height 0.13 mm., 0.14 mm.
13.— Both from right posterior ambulacrum, height 0.10 mm.
14.— From left anterior ambulacrum, height 0.9 mm.

.

All equally magnified.

“ALBATROSS” TROPICAL PACIFIG Ex. 1899-1900. — EGHINONEUS PLATE 16.

PLATE 17.

1-9. Echinonéus cyclostomus LEsKE.

Sphaeridia.
1-6.— Alcoholic specimen, test measuring 30 mm., 6, test measuring 26 mm. long. Barbados (?).

1.— Both from right posterior ambulacrum, height 0.22 mm., 0.20 mm.
2.— From right anterior ambulacrum, height 0.19 mm.

3.— Both from odd anterior ambulacrum, height 0.20 mm., 0.19 mm.
4.— Both from left anterior ambulacrum, height 0.17 mm., 0.19 mm.
5.— From left posterior ambulacrum, height 0.19 mm.

6.— Both from right anterior ambulacrum, height 0.20 mm.

7-9.— Aleoholic specimen measuring 23 mm. long. Fakarava Island, Paumotu Islands.

7.— Both from right posterior ambulacrum, height 0.13 mm., 0.12 mm.
8.— From odd anterior ambulacrum, height 0.14 mm.
9.— Both from left posterior ambulacrum, height 0.14 mm., 0.12 mm.

Figures 1-6 the magnification is slightly reduced, the others the same as those of Plate 16.

“ALBATROSS” TROPIGAL PAGIFIG Ex. 1899-1900. EGHINONEUS PLATE I?,

A.M Westeréren del l
AM MWesteréren del. B.Meisel lith

PLATE 18.

1-11. Echinonéus cyclostomus LESsKE.

Valves of tridentate pedicellariae.

1.— Stalk and head, 0.95 mm. long. )

2.— Valve A, 0.51 mm. interior view. }

3.— Valve B, 0.50 mm. interior view. |

4.— Valve B, 0.50 mm. interior view, profile. |

5.— Valve C, 0.47 mm. interior view.

6.— Valve C, 0.47 mm. exterior view. J
1-6.— Are from right anterior interambulacrum, midway between the actinal system and the

ambitus. Dry specimen, with spines measuring 34 mm. long. Lord Howe Island.

Of a single pedicellaria.

7.— Valve B, 0.47 mm. interior view, near the actinostome in odd posterior interambulacrum.

8.— Valve B, 0.47 mm. exterior view near the actinostome in odd anterior ambulacrum.

9.— Valve B, 0.45 mm. exterior view midway between actinal system and the ambitus, in right anterior
interambulacrum.

7-9.— Alcoholic specimen with spines measuring 15 mm. long. Makemo Island, Paumotu Islands.
10.— Valve C, 0.22 mm. exterior view.
11.— Valve C, 0.22 mm. interior view towards ambitus, actinal side, in left posterior interambulacrum.
Test measuring 34 mm. long. Lord Howe Island.

The measurement refers to height of valves natural size.
All of the same enlargement with exception of Figure 1, which is on a smaller scale.

oe

‘ EGHINONEUS PLATE 18.

“KY BATROSS TROPIGAL PAGIFIG Ex. 1899-1900.

B Meisel lith

=

:
MPL Terns
PLATE 19.

PLATE 19.

1-7. Echinonéus cyclostomus LrEske.

Valves of tridentate pedicellariae.

1.— Stalk and head, valve B in the centre. Height of head 0.63 mm.
2.— Valve A, 0.63 mm. interior view, profile.

3.— Valve B, 0.62 mm. interior view. Of a single pedicellaria.
4.— Valve C, 0.61 mm. exterior view. ¢
1-4 are taken from right posterior interambulacrum, near the actinostome. Alcoholic specimen, i

measuring 19 mm. long. Fakarava Island, Paumotu Islands.

5.— Valve B, 0.67 mm. interior view.

6.— Valve C, fragment, exterior view, both from odd posterior interambulacrum, towards aboral end
of anal system. Alcoholic specimen, measuring 23 mm. long. Fakarava Island.

7.— Valve B, 0.54 mm. interior view, from adoral end of anal system. Alcoholic specimen with spines,
measuring 26 mm. long. Barbados (?).

Magnification precisely as on Plate 18.

EGHINONEUS PLATE 19

bop 3

S15).

ae See
SS

AM Westereren del.

PLATE 20.

1-13. Echinonéus cyclostomus LrEske.

Valves of tridentate pedicellariae.

1.— Stalk and head, 0.65 mm. from aboral end of anal system. Specimen measuring 12 mm. long.
2.— Valve A, 0.30 mm. interior view.
3.— Valve B, 0.29 mm. exterior view.
4.— Valve C, 0.26 mm. interior view profile, from aboral end of anal system.
Test measuring 11 mm. long.
5.— Valve B, 0.32 mm. exterior view, midway between actinostome and ambitus, in right anterior
interambulacrum. Test measuring 13 mm. long.
6.— Valve B, 0.44 mm. exterior view, near actinostome, in right anterior interambulacrum. Test
measuring 13 mm. long.
7.— Valve B, 0.40 mm. exterior view, adoral end of anal system. Test measuring 13 mm. long.
8.— Valve B, 0.33 mm. exterior view, aboral end of anal system. Test measuring 10 mm. long.
9.— Valve B, 0.38 mm. exterior view, midway between actinostome and ambitus, in odd anterior
ambulacrum. Test measuring 12 mm. long.
10.— Valve B, 0.35 mm. exterior view, midway between actinostome and ambitus, in right posterior
interambulacrum. Test measuring 10 mm. long.
11.— Valve C, 0.34 mm. exterior view, near actinostome, in left anterior interambulacrum. Test
measuring 11 mm. long. >
12.— Valve B, 0.39 mm. exterior view, aboral end of anal system. Test measuring 18 mm. long.
13.— Valve C, 0.32 mm. exterior view, adoral end of anal system. Test measuring 18 mm. long.

Figures 1-7, and 9 are from specimens from Fakarava Island, Paumotu Islands, Figures 8, 10-13
are from specimens from Makemo Island, Paumotu Islands.

All the specimens were alcoholic.

Magnification as on Plate 19,

Of asingle pedicellaria.

“AT BATROSS’ TROPICAL PAGIFIG EX. 1899 -1900.

B.Meisel lith

AM Westeréren del

PLATE 21.

1-20. Echinonéus cyclostomus LEskKE.

Valves of ophicephalous pedicellariae.

1.— Stalk and head, 0.63 mm. long, from left posterior interambulacrum, actinal side of ambitus.

2.— Pedicellaria, 0.26 mm. valve C in centre, from right posterior interambulacrum.

3.— Valve A, 0.25 mm. exterior view.

4,— Valve B, 0.23 mm. interior view.

5.— Valve B, 0.23 mm. interior view profile. Of a single pedicellaria.

6.— Valve C, 0.22 mm. exterior view, from left posterior interambulacrum,
actinal side of ambitus.

7.— Valve C, 0.25 mm. exterior view.

8.— Valve A, 0.28 mm. exterior view, from right posterior interambulacrum, | same pedicellaria.
actinal side of ambitus.

Figures 1-8. Dry specimen with spines measuring 34 mm. long. Lord Howe Island.

9.— Valve B, 0.21 mm. interior view.

10.— Valve C, 0.20 mm. exterior view, from left posterior interambulacrum
towards apical system. Test with spines measuring 30 mm. long.
Lord Howe Island.

11.— Valve B, 0.16 mm. interior view.

12.— Valve C, 0.15 mm. interior view, from left anterior interambulacrum,
apicalsystem. Alcoholic specimen measuring 11mm.long. Fakarava
Island, Paumotu Islands.

13.— Valve B, 0.21 mm. interior view, from left anterior interambulacrum, midway between actino-
stome and ambitus. Alcoholic specimen, with spines measuring 15 mm.long. Makemo Island,
Paumotu Islands.

14.— Valve C, 0.19 mm. exterior view, from right anterior interambulacrum, actinal side of ambitus.
Test measuring 15 mm. long. Makemo Island.

15.— Valve A, 0.32 mm. interior view. }

16.— Valve B, 0.31 mm. interior view.

17.— Valve C, 0.28 mm. exterior view, from right posterior ambulacrum, to- } Of a single pedicellaria.
wards margin of anal plastron. Alcoholic specimen, with spines
measuring 30 mm. long. Barbados (?)

18.— Valve B, 0.24 mm. interior view from right posterior interambulacrum near apical system. Test
measuring 30 mm. long. Barbados (?)

19.— Valve C, 0.22 mm. exterior view, from left posterior interambulacrum. Alcoholic specimen
measuring 26 mm. long. Barbados (?)

20.— Valve C, 0.19 mm. exterior view, from left posterior interambulacrum, near apical system. Test
measuring 26 mm. long. Barbados (?)

Same pedicellaria.

| Same pedicellaria.

The enlargement of Figures 2 to 20 is the same, but is on a slightly larger scale than those of Plates
18-20.

“ALBATROSS TROPICAL PAGIFIG Ex. 1899-1900. EGHINONEUS PLATE él.

AMY fy }
A.M Wesiteeren.del. B Meisel lith.

PLATE 22.

1-26. Echinonéus cyclostomus LEsKE.

1-16. Valves of globiferous pedicellariae.

1.— Stalk and head, 0.74 mm. long, from left anterior ambulacrum, one third way between actinal
system and ambitus.
2.— Pedicellaria, 0.36 mm. valve C in centre, from right posterior interambulacrum, midway between
actinal system and ambitus.
3.— Valve A, 0.38 mm. interior view. ]
4.— Valve B, 0.37 mm. interior view. |
5.— Valve B, 0.37 mm. interior view, profile. } Of a single pedicellaria, same as Figure 1.
6.— Valve C, 0.36 mm. interior view. |
7.— Valve C, 0.36 mm. exterior view. J
8.— Valve A, 0.26 mm. exterior view.
9.— Valve C, 0.26 mm. interior view, from right posterior interambulacrum, | same pedicellaria.
ambitus.
10.— Valve B, 0.34 mm. interior view.
11.— Valve C, 0.32 mm. exterior view, from right posterior interambulacrum, Vise pedicellaria.
toward apical system. J
12.— Valve B, 0.32 mm. interior view, from right posterior interambulacrum, near genital plate.
1-12. Dry specimen with spines 34 mm. long. Lord Howe Island.

13.— Valve A, 0.28 mm. interior view, profile. |

14.— Valve B, 0.27 mm. interior view, from right posterior interambulacrum. Baine pedivellnne
Alcoholic specimen measuring 19 mm. long. Fakarava Island, .
Paumotu Islands.

15.— Valve B, 0.31 mm. interior view.

16.— Valve C, 0.30 mm. interior view, from right posterior interambulacrum, USamie peritcelireeel
near apical system. Alcoholic specimen, with spines measuring 30 | i
mm. long. Barbados (?). J

17-26. Valves of tridentate pedicellariae.

17.— Head and stalk, 0.51 mm. from left anterior interambulacrum, one third way between actinostome
and ambitus. Dry specimen, with spines measuring 30 mm. long. Lord Howe Island.

18.— Valve B, 0.17 mm. interior view.

19.— Valve B, 0.17 mm. interior view, profile.

20.— Valve C?, 0.17 mm. interior view.

21.— Valve C?, 0.17 mm. exterior view from anal system, near the inter-
ambulacrum. Dry specimen, with Spines measuring 34 mm. long.
Lord Howe Island.

22.— Valve B, 0.15 mm. interior view, from anal system. Alcoholic specimen, measuring 10 mm. long.
Makemo Island, Paumotu Islands.

23.— Valve A, 0.17 mm. interior view, from adoral end of anal system. Alcoholic specimen, measuring
18 mm. long. Makemo Island.

24.— Valve C, 0.31 mm. exterior view, from adoral end of anal system.

25.— Valve C, 0.23 mm. exterior view, from aboral end of anal system.

26.— Valve A, 0.31 mm. interior view, from aboral end of anal system.

f Same valve. Same specimen as Figure 17.

Same valve.

24-26. Alcoholic specimen, with spines measuring 26 mm. long. Barbados (?).

The enlargement of Figures 2 to 16 is the sameas Plate 18. Figures 18 to 26 are on a slightly larger,
but not identical scale; Figures 1-17 are smaller.

~

‘of
4)
0
G
c

B Meisel ith.

PLATE 23.

1-17. Echinonéus cyclostomus LESKE.

Valves of pedicellariae.

1.— Valve B, 0.12 mm. interior view. Tridentate pedicellaria, from anal system. Test with spines

measuring 4 mm. long.

2— Valve B, 0.13 mm. interior view. Tridentate pedicellaria, from right posterior ambulacrum, near

actinostome. Test with spines measuring 4 mm. long.

) Ophicephalous pedicellaria, from odd posterior interambula-
crum, near margin of anal system. Test with spines
measuring 4 mm. long.

5.— Valve B, 0.19 mm. interior view. Globiferous pedicellaria, from left posterior interambulacrum,

at ambitus. Test with spines measuring 4 mm. long.

— Valve B, 0.20 mm. interior view. Globiferous pedicellaria, from right anterior interambulacrum,

at ambitus. Test with spines measuring 5 mm. long.

7—Valve A. 0.22 cterior wiew | Globiferous pedicellaria, from right anterior interambula-

7. alve A, 0.22 mm. exterior view. a Set i : ;

nasa U Oe nnn tenioe ea | enti midway between actinostome and ambitus. Test

with spines measuring 5 mm. long.

9.— Valve B, 0.28 mm. interior view. Tridentate pedicellaria, from aboral end of anal system. Test

measuring 11 mm. Jong.

10.— Valve B, 0.37 mm. interior view. Tridentate pedicellaria, from aboral end of anal system. Test

measuring 20 mm. long.

11.— Valve B, 0.43 mm. interior view. Tridentate pedicellaria, from right anterior interambulacrum,

near actinostome. Test measuring 20 mm. long. 7

12.— Valve B, 0.47 mm. interior view. Tridentate pedicellaria, from odd posterior interambulacrum,

near ambitus, actinal side. Test with spines measuring 25 mm. long.

13.— Valve B, 0.47 mm. interior view. Tridentate pedicellaria, from aboral end of anal system. Test

with spines measuring 25 mm. long.

14.— Valve B, 0.49 mm. interior view. Tridentate pedicellaria, from adoral end of anal system. Test

with spines measuring 26 mm. long.

15.— Valve B, 0.43 mm. interior view. Tridentate pedicellaria, from left posterior interambulacrum,

near actinostome. Test measuring 28 mm. long.

16.— Stalk and head of a triphyllous pedicellaria, 0.29 mm. long, from right anterior interambulacrum,

near actinostome. Test measuring 11 mm. long.

17.— Valve of triphyllous pedicellaria, 0.04 mm. exterior view, from left anterior interambulacrum,

hear actinostome. Test measuring 11 mm. long.

3.— Valve A, 0.14 mm. exterior view-
4.— Valve B, 0.13 mm. interior view.

for)

Port Antonio, Jamaica. 1909.
Each order of pedicellaria is magnified almost identically except Figures 1 and 2, which are on a
larger scale.

NONEUS PLATE 23.

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AM Westeréren del

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PLATE 24.

1-7. Echinonéus cyclostomus Lesxkr.

Odd anterior ambulacrum.

1.— From test 6 mm. long,

2.— From test 8 mm. long,

3.— From test 9.5 mm. long, 7 ;
4.— From test 11 mm. long, Bort Snionio, Jamnateee
5.— From test 16 mm. long,

6.— From test 18 mm. long,

7.— From test 27 mm. long, Pacific (?).

Increase of the primary tubercles is indicated by numbers and letters.
Figures 6-7 are reduced in magnification, the others in relative size.

\

Bete

GHINONEUS PLAT

LG

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0, 09 ° 2) }) Dy Y (

“ALBATROSS TROPIC.

AM Westereren del.

PLATE 26.

1-12. Echinonéus cyclostomus Lreske.

1-S.— Order in which number of primary tubercles increase on the seventh plate from actinostome,

including the primordial; from left anterior interambulacrum, bordering on odd anterior ambulacrum,
is as follows.

1.— Seventh plate from mouth from a specimen 4.19 mm. long
2.— Seventh plate from mouth from a specimen 6 mm. long.
3.— Seventh plate from mouth from a specimen 8 mm. long.

4.— Seventh plate from mouth from a specimen 10 mm. long.
5.— Seventh plate from mouth from a specimen 12 mm. long.
6.— Seventh plate from mouth from a specimen 15 mm. long.
7.— Seventh plate from mouth from a specimen 17 mm. long.
8.— Seventh plate from mouth from a specimen 26 mm. long.

1-8.— From alcoholic specimens. Port Antonio, Jamaica. ~~

9.— Part of test showing primary and glassy tubercles, from left anterior interambulacrum, fourth
plate from actinostome. Diameter of boss 0.35 mm. ;

10.— Same as previous, from right anterior interambulacrum, midway between ambitus and genital
plate. Diameter of boss 0.29 mm.

11.— Half profile of a glassy tubercle, diameter 0.37 mm.

12.— Same in profile, and section of test.

9-12.— From an alcoholic specimen measuring 27 mm. long. Makemo Island, Paumotu Islands.
Figures 1-8, same enlargement.

E 25.

HINONEUS PLAT

ib

1899-1900.

Dx
ox

TROPICAL PAGIFIG

ALBATROSS:

TAT

iy

PLATE 26.

1-31. Echinonéus cyclostomus LESKE.

Spines.

1.— Spine, 3.10 mm. long,
2.— Spine, 1.51 mm. long, §
— Spine, 1.51 mm. long, detail of Figure 2, edge showing serration.
4.— Spine, 2.30 mm. long, from right posterior interambulacrum, midway between actinostome and

ambitus.

5.— Spine, 2.30 mm. long, detail of Figure 4, top view, larger magnification.
oa cea oe ae ee from left anterior interambulacrum at ambitus.

8.— Spine, _ long, from odd posterior interambulacrum, near anal system.

9.— Spine, _ long, detail of Figure 8, top view, larger magnification.

10.— Spine, 0.60 mm. long, from left anterior interambulacrum at ambitus.

11.— Spine, 0.60 mm. long, same as Figure 10, larger magnification, showing serrations.

12.— Spine, 2.18 mm. long, base and section of a spine.

13.— Spine, 2.18 mm. long, top view of Figure 12.

14.— Spine, 1 mm. long, from anal system.

15.— Spine, 1 mm. long, same as Figure 14, larger magnification, showing serrations.

16.— Stalk, 0.34 mm. long, of a globiferous pedicellaria, from right anterior interambulacrum, near

apical system.
17.— Stalk, 0.34 mm. long, same as Figure 16, larger magnification.
18.— Stalk, 0.44 mm. long, of an ophicephalous pedicellaria, from right anterior interambulacrum,
midway between ambitus and apical system.

19.— Stalk, 0.44 mm. long, same as Figure 18, larger magification. .

from left anterior interambulacrum, near actinostome.

w

1-19.— Lord Howe Island from a dry specimen, with spines measuring 34 mm. long.
Except for details the enlargement is the same. ‘i

20.— Spine, 1.32 mm. long, from right posterior ambulacrum, near actinostome.

21.— Spine, 1.32 mm. long, same as Figure 20, larger magnification.

22.— Spine, 1.90 mm. long, from left posterior ambulacrum, near anal system.

23.— Spine, 1.90 mm. long, same as Figure 22, section of base through milled collar.

24.— Spine, 0.50 mm. long, from right anterior interambulacrum, midway between actinostome and
ambitus.

25.— Spine, 0.50 mm. long, same as Figure 24, larger magnification.

26.— Spine, 0.44 mm. long, detail of an end, from right anterior interambulacrum near actinostome.

27.— Spine, 1 mm. long, from right anterior interambulacrum at ambitus. ;

28.— Spine, 0.72 mm. long, from right anterior interambulacrum, near apical system.

29.— Spine, 0.35 mm. long, from left anterior interambulacrum, near apical system.

30.— Stalk, 0.63 mm. long, of an ophicephalous pedicellaria, from right anterior interambulacrum, near
actinostome.

31.— Stalk, 0.63 mm. long, same as Figure 30, larger magnification. -

Figures 20-31, Makemo Island, Paumotu Islands, are from an alcoholic specimen, with spines
measuring 18 mm. long.

Enlarged slightly more than those from Lord Howe Island.

EGHINONEUS PLATE 26.

“ ALBATROSS’ TROPIGAL PACIFIG Ex. 1899-1900.

NAY OF AY 64 BE bic wr wCeN A OY A RT eT Be

Ui PAS Fak Ba ei On eared Hal WA Ol HLANEd CD, A
— ——

B Meisel lith

AM Westereren del.

PLATE 27. :

1-44. Echinonéus cyclostomus Lrsker.

Spines.

1.— Spine, 1.50 mm. long, from left anterior interamhulacrum, near actinostome.

2.— Spine, 1.50 mm. long, outline of serration of Figure 1.

3.— Spine 1.65 mm. long, from odd posterior interambulacrum, near actinostome.

4.— Spine, 2.6 mm. long, from right anterior interambulacrum, midway between actinostome and
ambitus.

5.— Spine, 1.22 mm. long, from right anterior interambulacrum, at ambitus.

6.— Spine, 0.82 mm. long, from left anterior interambulacrum, actinal side.

7.— Spine, 0.82 mm. long, detail of Figure 6, top view, larger magnification.

8.— Spine, 0.65 mm. long, from near apical system.

9.— Spine, 0.38 mm. long, from apical system.

10.— Spine, 0.22 mm. long, from the madreporic plate.

11.— Spine, 0.22 mm. long, same as Figure 10, larger magnification.

12.— Stalk, 0.34 mm. long, of an ophicephalous pedicellaria, from left posterior interambulacrum.

13.— Stalk, 0.34 mm. long, same as Figure 12, larger magnification.

14.— Spine, 1.20 mm. long, from right anterior interambulacrum, towards actinostome.

Figures 1-14. Fakarava Island, Paumotu Islands.

Figures 1-8, 12-13, are from an alcoholic specimen with spines measuring 23 mm. long. Figures 9,
10, 11, and 14 from an alcoholic specimen with spines measuring 11 mm. long. The enlargement is
same as those on Plate 26 from Makemo Island.

15.— Spine, 1.95 mm. long, from right posterior ambulacrum, near actinostome.
16.— Spine, 2.80 mm. long, from odd posterior interambulacrum, near anal system.
17.— Spine, 2.92 mm. long, from odd posterior interambulacrum, near anal system.
18.— Spine, 1.64 mm. long, from right anterior interambulacrum, at ambitus.
19.— Spine, 1.54 mm. long, from anal system.
20.— Spine, 1 mm. long, from apex.

* 21.— Spine, 0.42 mm. long, from madreporic plate. :
22.— Spine, 0.42 mm. long, same as Figure 21, larger magnification.
23.— Stalk, 0.52 mm. long, of a globiferous pedicellaria, from right anterior interambulacrum, abactinal

side.

24.— Stalk, 0.52 mm. long, same as Figure 23, larger magnification.

Figures 15-24, Barbados, (?) are from an aleoholie specimen, with spines measuring 30 mm. long.
Enlargement identical with those from Lord Howe Island.

Spine, 1.63 mm. long, from right posterior interambulacrum, near actinostome.

20-—
26.— Spine, 2.26 mm. long, from odd posterior interambulacrum, near anal system.
27.— Spine, 1.46 mm. long |

eee gana lone | from right anterior interambulacrum, at ambitus.

29.— Spine, 1.6 mm. long |

30.— Spine, 0.86 mm. long §

31.— Spine, 0.38 mm. long, from madreporie plate.

32.— Spine, 0.38 mm. long, same as Figure 31, larger magnification.

33.— Spine, 1 mm. long, from odd anterior ambulacrum, actinal side.

34.— Spine, 1 mm. long, top of Figure 33, larger magnification.

35.— Stalk, 1.4 mm. long, of an ophicephalous pedicellaria, from left anterior interambulacrum, actinal
side.

36.— Stalk, 1.4 mm. long, same as Figure 35, larger magnification.

37.— Spine, 0.56 mm. long, from right anterior interambulacrum, at edge of actinostome.

38.— Spine, 0.78 mm. long, from odd posterior interambulacrum, near anal system.

from right anterior interambulacrum, near apical system.

39.— Spine, 0.77 mm. long, from right anterior interambulacrum, at ambitus.
40.— Spine, 0.54 mm. long, from apex.

41.— Spine, 0.21 mm. long, from madreporic plate.
42.— Spine, 0.21 mm. long, same as Figure 41, larger magnification.
43.— Stalk, 0.32 mm. long, of a globiferous pedicillaria, from right anterior interambulacrum
44.— Stalk, 0.32 mm. long, same as Figure 43, larger magnification.

Figures 25-44, Port Antonio, Jamaica. Figures 25-36, are from an alcoholic specim
measuring 25 mm. long. Enlargement identical with those of Lord Howe Island.
alcoholic specimen measuring 4 mm. long, magnified on larger scale.

The position of sections prepared are indicated by dotted line.

EGHINONEUS PLATE 27.

PERE TA I

G Ex. 1899-1900.

FI

I

“ALBATROSS TROPIGAL PAG!

B.Meisel lith

AM Westersren del.

a

a

PLATE 28.

1-24. Echinonéus cyclostomus LESKE.

1— Actinal tube-foot 0.65 mm. long, seen in profile, from near actinostome in odd anterior ambulacrum.
2 — Actinal tube-foot, seen from above the disk, from right anterior ambulacrum.

3.— Profile of an actinal tube-foot, from odd anterior ambulacrum.

4.— Disk plates 0.7 mm. in diameter, seen from above, near actinostome, in odd anterior ambulacrum.
5.— One of the disk plates, whole disk 0.22 mm. in diameter, from right anterior ambulacrum, actinal

side.
6.— Disk plates 0.14 mm. in diameter, seen from above, from odd anterior ambulacrum, towards

apical system.

Figures 1-3, 5 and 6, are from a test with spines measuring 25 mm. long. Figure 4 from a test
with spines measuring 7 mm. long. Port Antonio, Jamaica.

7.— One of the disk plates, seen from below with yoke-shaped spicules, whole disk 0.22 mm. in diameter,
from odd anterior ambulacrum actinal side, test with spines measuring 30 mm. long.
Barbados (?).

8.— One of the disk plates, from tube-foot near actinostome, left anterior ambulacrum, test with spines
measuring 30 mm. long. Barbados (?).

9.— One of the disk plates from tube-foot near actinostome, left anterior ambulacrum, test with spines
measuring 26 mm. long. Barbados (?).

10.— Abactinal tube-foot 0.22 mm. long, seen in profile, from near ocular plate, odd anterior ambulacrum,
test with spines measuring 12 mm. long. Makemo Island, Paumotu Islands.

11.— Disk plates 0.15 mm. in diameter, seen from above, actinal side, odd anterior ambulacrum, test
with spines measuring 12 mm. long. Makemo Island. =

12.— One of the disk plates, whole disk 0.20 mm. in diameter, from odd anterior ambulacrum, actinal
side, test with spines measuring 18 mm. long. Makemo Island.

13.— Disk plates 0.10 mm. in diameter, seen from above, near the ocular plate, in odd anterior ambula-
crum, test with spines measuring 12 mm. long. Makemo Island.

14.— One of the disk plates, whole disk 0.19 mm. in diameter, from odd anterior ambulacrum, actinal
side, test with spines measuring 23 mm. long. Fakarava Island, Paumotu Islands.

15.— Peripodium at the edge of actinostome. :

16.— Fifth peripodium from actinostome.

17.— Peripodium at the ambitus.

18.— Peripodium near ocular plate.

Figures 15-18, odd anterior ambulacrum, test with spines measuring 34mm. long. Lord Howe Island.

19.— First and second peripodia at the edge of actinostome, odd anterior ambulacrum, test with spines,
measuring 37 mm. long. Mauritius.

20.— Fifth peripodium from actinostome, same specimen as Figure 19.

21.— Peripodium at the edge of actinostome, odd anterior ambulacrum, test without spines measuring
27 mm. long. Pacifie (?).

22.— Fifth peripodium from actinostome, same specimen as Figure 21.

23.— Fifth peripodium from actinostome, odd anterior ambulacrum, test with spines measuring 27 mm.
long. Makemo Island.

24.— Fifth peripodium from actinostome, odd anterior ambulacrum, test with spines measuring 26 mm.
long. Jamaica.

The enlargement of all the figures is not identical.

“ALBATROSS’ TROPIGAL PAGIFIG Ex. 1899-1900.

A.M Westereren del.

EGHINONEUS PLATE 28.

B Meisel lith

PLATE 29.

1-14. Micropetalon purpureum A. Aacassiz and H. L. Crark.

1.— Actinal side of a dry specimen, 17 mm. long including spines, from the Hawaiian Islands.
2.— The same from the abactinal side.

3.— The same in profile, facing left anterior interambulacrum and left posterior interambulacrum.
4.— Exterior view of abactinal system, denuded, showing the madreporite and genital pores.

5.— The same as Figure 4, from the interior.

6.— Odd anterior ambulacrum, showing pores and arrangement of primary tubercles and milliaries.
7.— Seventh plate from the edge of actinostome, in left anterior interambulacrum.

8.— Plate from posterior interambulacrum, abactinal side near the apex.

9.— Peripodium, at the edge of actinostome in odd anterior ambulacrum.

10.— Fifth peripodia from the actinostome.

11.— One of the peripodia in the ambitus.

12.— Peripodium near the ocular plate.

13.— Sphaeridium, first from edge of actinostome, in odd anterior ambulacrum.

14.— Second sphaeridia, from same ambulacrum as preceding.

“ALBATBOSS' TROPICAL PACIFIC Ex. 1899-1900. EGHINONEUS. PLATE 29!

AM Westergren del. B Meisel lith

PLATE 30.

Micropetalon purpureum A. A

Arrangement of the coronal plates, seen from inside o
Hawaiian Islands. a

“ALBATROSS” TROPICAL PACIFIC EX. 1899-1900.

EGHINONEUS PLATE30.

BiMeisel Jith.

A.M Westereren del.

PLATE 31.

1-17. Micropetalon purpureum A. AGassiz and H. L. Cuarx.

1.— Interior view of the actinal side.

2.— Anal system, seen from the outside.

3.— Stalk and head of an ophicephalous pedicellaria, measuring 1.13 mm. long, from the abactinal
side, at the ambitus, from the right posterior interambulacrum.

4.— Ophicephalous pedicellariae, 0.27 mm., valve B in centre, from right anterior interambulacrum
from the abactinal side.

5.— Valve A, 0.28 mm. exterior view.

6.— Valve B, 0.26 mm. exterior view. | Of a single ophicephalous pedicellaria, from the abactinal side

7.— Valve C, 0.25 mm. interior view. / at the ambitus, from right anterior interambulacrum.

8.— Valve C, 0.25 mm. exterior view, from the right anterior interambulacrum, from the abactinal side.

9.— Spine, 1.92 mm. long, from right anterior interambulacrum, near the edge of the actinostome.

10.— Spine, 1.44 mm. long, from right anterior interambulacrum towards the summit.

11.— Spine, 0.95 mm. long, from odd anterior ambulacrum, at the edge of actinostome.

12.— Spine, 0.65 mm. long, from right posterior interambulacrum, near the summit.

13.— Spine, 0.81 mm. long, detail of an end, from right anterior interambulacrum, from the abactinal

side.
14.— Disk plate, 0.21 mm. in diameter, seen from above, from odd anterior ambulacrum, from the
actinal side. :
15.— Actinal tube-foot, 0.50 mm. long, seen in profile, from the edge of actinostome, in odd anterior
ambulacrum.

16.— Abactinal tube-foot, diameter of the disk 0.11 mm. from the apex. —
17.— Spicules from the tube.

The magnification is identical in figures of the same order.

IS_PLATE 31.

BUS

GHINONE

FE

Mo

wa 3
w 5
=, DV Ny ie
rd ay \
= rr ee &
ioe] ss
4 2

Memoirs of the Museum of Comparative Zodlogy
AT HARVARD COLLEGE.

Wot NoxeneX NOs:

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

U.S. N., COMMANDING.

XXXII.

ASTEROIDEA.

By HUBERT LYMAN CLARK.

WITH SIX PLATES.

[Published by Permission of H. M. Samra, U. S. Commissioner of Fish and Fisheries].

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

Ferpruary, 1920.

CONTENTS.

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE TROPI-
CAL PACIFIC, in charge of Alexander Agassiz, by the U. S. Fish Commission Steamer
“Albatross,”’ from October, 1904 to March, 1905, Lieut. Commander L. M. Garrett,
U.S. N., Commanding. XXXII. Astrrormea. By Husperr Lyman CuarK. With
46 pp. and 6 Plates,

TABLE OF CONTENTS.

INTRODUCTION
SYSTEMATIC ACCOUNT

PORCELLANASTERIDAE
EREMICASTER PACIFICUS (LUDWIG)
TENEBRARIUS FISHER
vicinus (Lupwia). Plate 2° fig. ue 8
CreNnopiscUs CRISPATUS (RETZIUS)
THORACASTER MAGNUS Lupwic. Plate 1, fir its 2
SryRACASTER MONACANTHUs Lupwi«. Plate 2, fig. 1, 2
PAUCISPINUS Lupwia. Plate 2, fig. 3, 4
ALBATROSSIA NuDA (Lupwic). Plate 2, fig. 5,6 .

ASTROPECTINIDAE
DyTASTER DEMONSTRANS LupWIG .

BENTHOPECTINIDAE
PECTINASTER AGASsIz0 (LUDWIG)

GONIASTERIDAE
PSEUDARCHASTER PECTINIFER LUDWIG . :
LIToNOTASTER TUMIDUS H. L. CuarK. Plate 3, fee 3-6

OREASTERIDAE
NIDORELLIA ARMATA GRAY

LINCKIIDAE
LINCKIA GUILDINGH GRAY
PHARIA PYRAMIDATA GRAY

ECHINASTERIDAE
_ HENRICIA GRACILIS (LUDWIG)

PTERASTERIDAE
HYMENASTER (LIST OF SPECIFIC SEE)
(Iiey TO SPECIES) :
CREMNODEsS H. L. Cuark. Plate 4, fig. 1
TRIAS H. L. CuarK. Plate 3, fig. 1, 2

ZOROASTERIDAE
(Key To scene)
ZOROASTER (LIST OF SPECIFIC NAMES)
MAMMASTER PERRIER .
CNEMIDASTER SLADEN .
(Ky TO sPEctrEs)
PROGNASTER PERRIER .
PHOLIDASTER SLADEN
(Key TO SPECTES)
MyxopirMA FISHER
(Key TO SPECTES)
ByYTHIOLOPHUS FISHER .
JZoRoASTER WyviILLe THOMSON
(Key TO SPECIES) : ‘ é ‘
PERARMATUS H. L. CuarK. Pilate 4, fig. 2
MAGNIFIcUs LuDWwIG . 5 ;

PAGE

75

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76
77
78
78
79
80
81

82

82

82
83

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86
86

86

87
87
89
91
93

94
96
94
97
7
98
98
98
99
99
99
99
100
100
102
104

74 CONTENTS.

ASTERITDAE
HELIASTER CUMINGI GRAY .
MULTIRADIATUS GRAY . :
SryLasTERIAs PASCHAE H. L. Crark. Plate 4, aon 3

BRISINGIDAE . - woke 6
BRISINGELLA MONACANTHA H. L. Cure Plate 5, fig. 3, 4. Bm P

FREYELLIDEA BREVISPINA H. L. Cuark. Plate 5, fig. 1,2 . a “
ocrorapraTa H. L. CuarK. Plate 6, fig. 1, 2 F ‘
ottcopracsata H. L. CuarKk. Plate 6, fig. 3, 4 : :
TUBERCULATA (SLADEN) . z 5 3 é

EASTERN TROPICAL PACIFIC ASTEROIDEA.

INTRODUCTION.

THE collections of sea-stars made by the ALBATROss on her Tropical Pacific
expeditions were not large, but as they contained much valuable material from
deep water they were entrusted to Prof. Hubert Ludwig, by whom the report
on the Panamic collection of 1891 was prepared. The collection made in 1899-
1900 contained but forty-two specimens of thirteen species, of which ten were
well-known littoral forms while three were deep-sea species, new to science;
these thirteen species are included in the Memoir on the Panamic starfishes
which was published in 1905 (Mem. M. C. Z., 32). The collection made in
1904-05 was much larger and Ludwig never completed his work on it. In 1907
(Zool. Anz., 31, p. 312-319) he published a preliminary description of five new
species and a new variety of Porcellanasteridae, but his study of the other
families was unfinished at the time of his death in 1913. Later the collection
was sent to Cambridge together with his notes, some of which were apparently
in form for publication. It was at first thought that these notes would be of
service in the preparation of the present report, but it soon became evident that
the correlation between the notes and the collection was too imperfect to permit
this. There are notes on species, including descriptions of new forms, which
are not in the collection as returned to Cambridge and there are many species
in the collection not mentioned in the notes. Under the circumstances there-
fore, I have decided to base this report exclusively on the collection as returned
to Cambridge.

The collection at present consists of 235 specimens of twenty-eight species
and one variety, but 148 of the specimens represent three species and four
additional species total fifty specimens. Three fourths of the species therefore
are represented on an average by fewer than two specimens each. Of the twenty-
eight species, six are littoral and twenty-two are deep-water forms. Of the
littoral species, five are common and long-known species, while one is of ex-
ceptional interest, being a new asteriid from Easter Island. Of the deep-water
species, eight are as yet undescribed forms while five others were new to science
when the collection was sent to Ludwig; these (as already stated) have been

76 PORCELLANASTERIDAE.

named and described by him. Of the other nine species, all but one were taken
by the ArBaTrross Expedition of 1891.

Half of the deep-water species described as new belong to the Brisingidae,
while a fifth member of the family, in this collection, was hitherto known only
from the Atlantic Ocean. These facts illustrate well how characteristic of the
deep-water fauna the Brisingidae are and how little that fauna is as yet known.
It is worthy of note that of the more than a dozen species of Brisingidae now
known from the Pacific, not one is in the present collection.

With the increasing knowledge of the deep-sea fauna, several genera of
sea-stars have been enlarged by numerous species until it is by no means easy
to determine the various forms assigned to them. I have therefore attempted
the revision of Hymenaster and Zoroaster. As the latter genus includes the
bulk of the Zoroasteridae, the revision is extended to include the other genera
and species thereof. Artificial keys to the species which seem entitled to recogni-
tion are included. Complete lists of the species proposed up to the present
time, in these genera, with the necessary bibliographical references, are also
given.

SYSTEMATIC ACCOUNT.

PORCELLANASTERIDAE.
Eremicaster pacificus.

Porcellanaster pacificus Lupwie, 1905. Mem. M. C. Z., 32, p. 89.
Eremicaster pacificus Fisaer, 1907. Zool. Anz., 32, p. 14.

These specimens, in which R = 15 and 22 mm., are not peculiar in any
way, but agree well with the original material from the Panamic region. I
fully agree with Fisher, in dissent from Ludwig, that the number of cribriform
organs is a more important, and also a more available, generic character than the
presence or absence of the segmental papillae. The bathymetrical range is
considerably increased by the present record and the geographical range is
extended to the south about 300 miles.

Station 4647. Eastern Tropical Pacific, 4° 33’ S., 87° 42’ 30” W., 2,005 fms. Bott. temp. 35.5°. Lt. gy.
and br. glob. oz.

Station 4649. Eastern Tropical Pacific, 5° 17’ S., 85° 19’ 30” W., 2,235 fms. Bott. temp. 35.4°. Fne.
stky. gy. m.

Two specimens.

Eremicaster tenebrarius.

Porcellanaster (Eremicaster) tenebrarius Fisaer, 1905 (10 June). Bull. U. S. Bur. Fish., 24, p. 293.
Porcellanaster waltharii Lupwie, 1905 (July). Mem. M. C. Z., 32, p. 92.
Eremicaster tenebrarius Lupwie, 1907. Zool. Anz., 31, p. 318.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 77

This species has been so well-described and figured by Fisher (1911. Bull.
76 U.S. N. M., p. 24-29), and its variations so fully discussed, that nothing of
importance can be added. There seems to be no doubt of the identity of wal-
tharti and tenebrarius. The present series is of interest only because the largest
(R. = 45 mm.) is somewhat larger than Fisher’s specimens and because of the
range extension. The bathymetrical range is extended nearly 600 fathoms
while the geographical range is extended southward almost 800 miles.

Station 4647. Eastern Tropical Pacific, 4° 33’S., 87° 42’ 30” W., 2,005fms. Bott. temp. 35.5°. Lt. gy.
and br. glob. oz.

Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 35’ 36” W., 2,370 fms. Bott. temp. 35.3°. Fne.
gn. m., mang. nod.

Station 4666. Eastern Tropical Pacific, 11° 55’ 30” S., 84° 20’ 18” W., 2,600 fms. Bott. temp. 34.9°.
Lt. gy. oz.

Station 4672. Peru: southwest of Palominos Light House, 88 miles, 2,845 fms. Bott. temp. 35.2°.
Fne. dk. br. infus. m.

Station 4717. Eastern Tropical Pacific, 5° 11’ S., 98° 56’ W., 2,153 fms. Bott. temp. 35.2°. Rd. ¢.,
glob. oz.

Twenty-four specimens.

Eremicaster vicinus.
Plate 2, fig. 7, 8.

Porcellanaster vicinus Lupwie, 1907. Zool. Anz., 31, p. 318.
Eremicaster vicinus FisHer, 1907. Zool. Anz., 32, p. 14.

Although Ludwig’s description is very brief, it gives all the essential char-
acters of this species and a detailed account now seems quite superfluous. There
is a good series of specimens, ranging from 19 to 32 mm. in diameter and showing
little diversity in structure, save in the armature of the superomarginal plates;
in three specimens (one from 4670 and the only two individuals from 4672),
there are no spines on the superomarginals and these are the ones Ludwig has
called ‘“‘var. inermis.”’ One specimen has the terminal third of a ray curiously
doubled; seen from above, the abnormal width and the two terminal plates,
coalesced along their inner margins, are striking; on the lower surface there are
two distinct ambulacral furrows, each with six or seven pairs of tube-feet.

Fisher (1911. Bull. 76 U.S. N.M., p. 30) says that “vicinus is insecurely
separated from pacificus” but I do not think he would feel so if he had compared
specimens. Besides the absence of actinal interradial spinelets, vicinus has two
characteristics which easily separate it from pacificus. One of these is found
in the adambulacral spines, which are very small (short and slender) and are
placed close together at the adoral end of the plate, while the other and more
conspicuous is in the spinulation of the oral plates, which have only one, or

78 PORCELLANASTERIDAE.

sometimes two minute conical spinelets near the center of the margin, instead
of 2-5 large, flat spines occupying practically the entire margin. While the
abactinal surface of vicinus is thus indistinguishable, by any constant character,
from that of pacificus, the oral surface is separable at a glance.

Station 4670. Peru: west of Palominos Light House, 105 miles, 3,209fms. Bott. temp. 35.4°. Fne.

dk. br. m.
Station 4672. Peru: southwest of Palominos Light House, 88 miles, 2,845 fms. Bott. temp. 35.2°.

Fne. dk. br. infus. m.
Forty-six specimens.
Ctenodiscus crispatus.

Asterias crispata Retztus, 1805. Diss. Ast., p. 17.
Ctenodiscus crispatus Di@BEN AND Koren, 1846. K. Vet. Akad. Handl. f. 1844, p. 256.

So fully has this well-known species been discussed by earlier writers and
particularly by Fisher (1911, Bull. 76 U. 8. N. M., p. 31-37), it would be quite
superfluous to give space to its diversities here. The series at hand is a large
one but from only a single station, and the specimens range in diameter from 15 to

70 mm.

Station 4631. Panama: off Mariato Point, 72 miles, 774 fms. Bott. temp. 38°. Gn. s.

Thoracaster magnus.

Plate 1, fig. 1, 2.
Lupwie, 1907. Zool. Anz. 31, p. 313.

This truly superb species has been sufficiently described by Ludwig, who
has also pointed out some of the characteristic differences between it and the
genotype, which was taken by the CHALLENGER in the Atlantic in 2,400 fms.
Since Ludwig described magnus, Koehler has published an account of a third
species of the genus, alberti, taken by the Investicaror in the Indian Ocean in
1,504 fms. But alberti is obviously different in many particulars from either
of the other species, so that the genus contains three very well-marked forms.

The cribriform organs of magnus tend to merge together to a very marked
degree, and apparently this is a matter of age. For in a specimen with R =
23 mm., these organs are quite distinct and although the three middle pairs
are very broad, much wider than the interspaces which separate them, they do
not merge at all; the outer pair are so narrow and inconspicuous, one would
scarcely consider them cribriform organs. On the other hand in a specimen
with R = 73 mm., all fourteen of the organs are more or less merged together;
those near the interradius are merged for practically their full height, being

EASTERN TROPICAL PACIFIC ASTEROIDEA. 79

separated by only an insignificant bare elevation on the upper edge of the supero-
marginal plate, and by a similar low knob about twice as large on the lower
edge of the inferomarginals; distally these knobs become gradually longer and
more conspicuous, though not noticeably higher, and finally, between the sixth
and seventh organs on each side, they permit the merging of the organs only
along the line between the upper and lower marginal plates. In large specimens,
the low elevations on the inferomarginals bear scattered, small spinelets of
diverse sizes.

In another particular, magnus differs markedly from the other two species
of the genus, and that is in the series of abactinal plates which extends to the
tip of the arm or nearly so. In a specimen with R = 23 mm. this series is .60
mm. wide clear to the terminal plate; the plates composing it are of irregular
size and form and show no definite arrangement; they are largest distally (but
not close to the terminal plate where they are very small) and some of them may
be fully .60 mm. across; the larger plates and even the smaller distal ones bear
no spinelets but have a smooth, slightly convex surface. In a large specimen,
with R = 73 mm., the plates do not reach the extreme tip of the arm, but are
shut off from the terminal plate by the meeting of three pairs of superomarginals;
the plates are more angular and flatter than in the smaller specimen and their
surface is somewhat coarsely shagreened; there is a very abrupt transition
from the small spinelet-bearing plates of the disk to the bare median series of
the arm; this occurs about 35 mm. from the arm-tip.

The disk and cribriform organs are yellow-brown in the preserved speci-
‘mens, with all the marginal plates, bare plates of arms and whole lower surface
more or less nearly white. In size the range is from R = 23 to R = 98 mm.

Station 4647. Eastern Tropical Pacific, 4° 33’ S., 87° 42’ 30’”” W., 2,005 fms. Bott. temp. 35.5°. Lt.
gy. and br. glob. oz.

Station 4649. Eastern Tropical Pacific, 5° 17’ S., 85° 19’ 30” W., 2,285 fms. Bott. temp. 35.4°. Fne.
stky. gy. m.

Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 36’ W., 2,370 fms. Bott. temp. 35.3°. Fne. gn.
m., mang. nod.

Station 4717. Eastern Tropical Pacific, 5° 11’ S., 98° 56’ W., 2,153 fms. Bott. temp. 35.2°. Rd. «¢.,
glob. oz.

Nine specimens.
Styracaster monacanthus.
Plate 2, fig. 1, 2.
Lupwie, 1907. Zool. Anz., 31, p. 315:

While the original description of this unique specimen is adequate, Ludwig
does not discuss its relationship to other members of the genus, although he

80 PORCELLANASTERIDAE.

himself describes four new species in his relatively brief paper. But the omis-
sion is not serious for the present species is notably distinct and might well be
made the type of a new genus. It resembles S. chuni and S. paucispinus in
the large disk and short arms; the general facies is thus very different from that
of the typical members of Styracaster. But the absence of paxillae and the
presence of only five narrow eribriform organs distinguishes monacanthus at
once from its two nearest allies and these differences are accentuated by the
very low and wide interradial marginal plates and the presence of only a single
spine on the supramarginal series of plates of each arm. The low, rounded
scale-like spines on the margin of the oral plates are an added feature worthy
of note. The disk is light gray and the arms and marginal plates are nearly
white, in slight contrast.

Station 4701. Eastern Tropical Pacific, 19° 11’ 30” S., 102° 24’ W., 2,265 fms. Bott. temp. 35.5°.
Dk. br. choc. c., mang. nod.

One specimen.

Styracaster paucispinus.
Plate 2, fig. 3, 4.

Lupwie, 1907. Zool. Anz., 31, p. 315.

Ludwig’s description of this species is somewhat more ample than that of
monacanthus but as in the case of that species, he does not discuss its relation-
ships. It agrees with S. armatus, spinosus, and edwardsi in the possession of
only three cribriform organs in each interbrachial arc; in the great breadth of
these, paucispinus is nearest to armatus. But it differs very markedly from all
these species, in its very short arms, R equalling 2.5r or less, whereas in the three
other species, R = 3r or more. Associated with this shortness of arms is a
reduction in the number of superomarginal spines which are never more than
three to an arm and may be one only; Ludwig says ‘‘two or three” but I fail to
find more than two in any case; the longest ones are scarcely 2 mm. high and
are quite thick at the base. The “winzigen, granuloiden stachelchen” on the
ventrolateral plates are so minute as to hardly warrant the name, and in one
specimen appear to be quite wanting. The adambulacral plates have a marked
depression or shallow furrow on the ventral surface; this runs from the inner
adoral corner of the plate, where it is deepest, to the outer aboral corner, where
it flattens out entirely.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 81

There is little color left in these specimens, which are nearly white, only
the disk and the cribriform organs being more or less brownish.

Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 35’ 36” W., 2,370 fms. Bott. temp. 35.3°. Fne.
gn. m., mang. nod.

Two specimens.

Albatrossia nuda.
Plate 2, fig. 5, 6.
Albatrossaster nudus Lupwic, 1907. Zool. Anz., 31, p. 318.

The very small starfish upon which this species is based is unquestionably
congeneric with the two somewhat larger specimens upon which A. semimargin-
alis was founded by Ludwig, but the reduction of the inferomarginal plates
has not gone so far, and since the disk is almost completely bare of spines, it is
probably best to consider the present specimen representative of a different
species. But Ludwig’s proposed change of the generic name from Albatrossia
to Albatrossaster is quite unjustifiable for Albatrossia is a different word from
Albatrossa with which Ludwig feared it might be confused. The confusion
does not seem probable, but in any case, the International Commission on
Nomenclature fully settled the matter in their Opinion 25 (July, 1910), dealing
with the identical case of Damesella vs. Damesiella. Albatrossaster must
therefore be considered as a synonym of Albatrossia.

The holotype of A. nuda is very well-preserved, save for the breakage or
loss of the large spines on the terminal plate. R = 7 mm. andr = 4.5. The
terminal plate is 1 mm. long and 2 mm. broad, with a deeply concave proximal
margin; it carries three spinelets, nearly or quite a millimeter long, one at the
middle of the upper margin and one at each of the lower distal corners. The
cribriform organ is more than a millimeter wide and the anal tube is nearly a
millimeter long. The adambulacral armature consists of two flat, wide, pointed
spinelets, subequal or the distal one larger. Two similar spinelets occur on the
free lateral margins of the much swollen and conspicuous oral plates; at the
inner end of these plates, situated on the suture between them is a single, large,
oral spine. Ventrolateral plates, like disk, smooth and without spinelets.
Color of disk pale dull reddish; marginal plates nearly white; lower surface
tinged with dull reddish.

Station 4647. Eastern Tropical Pacific, 4° 33’S., 87° 42’ 30” W., 2,005fms. Bott. temp. 35.5°. Lt. gy.
and br. glob. oz.

One specimen.

82 BENTHOPECTINIDAE.

ASTROPECTINIDAE.
Dytaster demonstrans.

Lupwie, 1905. Mem. M. C. Z., 32, p. 41.

There is a good series of this species, both young (R = 10-25 mm.) and
adults (R up to 110 mm.) but Ludwig’s very full account, with its numerous
figures, leaves no occasion for extended notice. While I agree with Fisher that
demonstrans is probably identical with gzlberti, I have not seen specimens of the
latter and therefore leave the point for future settlement. The following sta-
tions extend the range of demonstrans some 500 miles southward, and bathy-
metrically 150 fms.

Station 4647. Eastern Tropical Pacific, 4° 33’ S., 87° 42’ 30” W., 2,005 fms. Bott. temp.35.5°. Lt. gy.

and br. glob. oz.
Station 4649. Eastern Tropical Pacific, 5° 17’S., 85° 19’ 30” W., 2,235fms. Bott. temp. 35.4°. Fne.

stky. gy. m.
Station 4656. Eastern Tropical Pacific, 6° 54’ 36’ S., 83° 34’ 18” W., 2,222 fms. Bott. temp. 35.2°.

Fne. gn. m., mang. nod.
Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 35’ 36” W., 2,370 fms. Bott. temp. 35.3°. Fne.

gn. m., mang. nod.

Eighteen specimens.

BENTHOPECTINIDAE.
Pectinaster agassizii.

Cheiraster agassizii Lupwic, 1905. Mem. M. C. Z., 32, p. 1.
Pectinaster agassizii Lupwie, 1910. Sitz. K. Preuss. Akad. Wiss., 23, p. 449.

These specimens are in rather poor condition and none have the arms
unbroken but R ranges from about 40 to 80 mm. Some specimens have a few
small pedicellariae on the abactinal surface close to the superomarginal plates
at the base of the rays but there are no intermarginal pedicellariae. These
specimens, while still agassizii, show some approach to Fisher’s subspecies P. a.
evoplus from farther north. The exact locality where they were taken is not
certain, but it was probably at

Station 4631. Panama: off Mariato Point, 72 miles, 774 fms. Bott. temp. 38°. Gn. s.

Eleven specimens.

GONIASTERIDAE.
Pseudarchaster pectinifer.

Lupwie, 1905. Mem. M. C. Z., 32, p. 106.

These specimens, with R = 60 and 80 mm. respectively, are somewhat
intermediate between that originally described by Ludwig and the one discussed

EASTERN TROPICAL PACIFIC ASTEROIDEA. 83

by me in 1913 (Bull. Amer. Mus. Nat. Hist., 32, p. 192). The number of adam-
bulacrals in proportion to ten inferomarginals is either nine or ten, while the
number of adambulacral spines is from six to eight, and there are from five to
eight spines on the ventral surface of the plate. On the other hand the project-
ing angle of the adambulacrals is not near the aboral end of the plate, but in
the larger specimen is about at the middle and in the smaller is distinctly adoral.
Probably these details of the adambulacral plates show considerable diversity
in the species.

The armature of thé superomarginal plates in the present specimens some-
what resembles that of P. dissonus for from four to eight of the granules on the
outer (lower) end of the superomarginals in the interbrachial are are more or less
elongated into flattened, bluntly pointed spinelets. But these spinelets do not
seem to be encased in ‘‘membranous sheaths” nor are they as long as in typical
dissonus.

Station 4654. Peru: off Aguja Point, 24 miles, 1,036fms. Bott. temp. 37.3°. Dk. br. m.

Two specimens.

Litonotaster tumidus,! sp. nov.

Plate 3, fig. 3-6.

R = 28 mm.; r= 14mm.; R=2r. Disk pentagonal, the arms arising
quite abruptly from the angles. Br.= 6 mm. at base and nearly 2 mm. just
before tip. In some specimens, the body is not noticeably pentagonal, the inter-
brachial ares being very well-rounded. Thus in a specimen with R = 27 mm.,
r = 11.5 mm. and br., at the level of the interbrachial arcs, 11 mm., the form
is quite evenly stellate. In all cases however, the disk is more or less swollen;
in the holotype, the vertical diameter at center of disk is 11 mm. while at the
margin the thickness is only 3.5 mm.

Abactinal surface covered by numerous circular or rounded-polygonal,
thin plates, .5-1 mm. in diameter, not very firmly united together and hence
forming a flexible covering. In each interradius but one, is a circular plate,
evidently larger than its neighbors, about 1.3 mm. across; in the fifth interradius
is the madreporite, a somewhat tumid, rounded-triangular plate, 1.5 mm.
across, adjoined on each of its three sides by a plate about 1 mm. wide and .75
mm. high. Excepting the madreporite, these interradial plates are discernible
only in dry specimens. In each radius, at the base of the arm, is a group of

1tumidus = swollen, in reference to the flexible, puffed upper surface of disk.

84 GONIASTERIDAE.

4-12 plates, noticeably larger than the others, and among these are the only
papulae to be found, but even these are small and inconspicuous. All the
abactinal plates are surrounded by a series of small rounded granules; on the
disk, the surface of each plate also carries several (3-15) similar granules; these
may be crowded but are usually rather well-spaced. On the arms, the granules
on the surface of the plates become few and disappear, so that at the tips of the
arms, the plates entirely lack them, only the marginal series being present there.

Marginal plates 15 on each side of each ray, or 16 in the inferomarginal
series; the plates in the two series are of about equal size or the inferomarginals
are somewhat larger than the superomarginals in the interbrachial are and
somewhat smaller at the very tip of the ray. Distally each plate is surrounded
by a marginal series of small granules, like those of the abactinal plates, while
the surface of the plate is bare, but as one passes towards the interradius, granules
appear on the surface and in the interbrachial are pretty well cover the plates;
those on the inferomarginals are larger than those on the upper series and are
quite angular and more or less pointed. Terminal plate slightly tumid, smooth,
transversely oval, not conspicuous.

Actinolateral plates squarish or polygonal not arranged in very definite
series, except one row adjacent to the adambulacrals; the plates of this row are
the largest and proximally are more than a millimeter square. They extend
out two thirds the length of the arm, beyond which the adambulacrals abut
directly on the inferomarginals. All the actinolateral plates are moderately
well-covered with spaced, pointed spinelets, considerably larger than the granules
of the abactinal surface. Adambulacral plates squarish, proximally about
equal to the adjoining actinolaterals but becoming larger (relatively only, of
course) at middle of arm. Each plate bears a marginal series of five or usually
four subequal, slightly tapered blunt spines, about a millimeter long; im-
mediately external to this marginal series, the surface of the plate is bare, but
along the outer margin are 4-8 pointed granules or low spinelets similar to those
of the actinolateral plates, but perhaps a little larger; these are arranged in
one or often two distinct series. Oral plates large but not very tumid; each
carries a marginal series of 10-12 spines similar to those of the adambulacral
plates, except that the one at the tip of plate (proximally) is noticeably stouter
than the others; on the surface of the plate are 10-14 low spinelets like those of
the actinolateral plates but a little larger.

Pedicellariae are exceedingly rare but on each specimen critically examined,
one was found; this was composed of two wide, blunt, erect valves, slightly

EASTERN TROPICAL PACIFIC ASTEROIDEA. 85

wider at tip than basally; it occurred on the surface of an adambulacral plate
near the middle of the arm. In the smallest specimen, half a dozen of these
pedicellariae were found on the actinolateral plates.
Color, in alcohol, light yellow-brown, which dries out to a dingy whitish.
Station 4656. Eastern Tropical Pacific, 6° 54’ 36” S., 83° 34’ 18” W., 2,222 fms. Bott. temp. 35.2°.
Fne. gn. m., mang. nod.

Station 4672. Peru; southwest of Palominos Light House, 88 miles, 2,845 fms. Bott. temp. 35.2°.
Fne. dk. br. infus. m.

Twelve specimens.

The holotype is from Station 4672.

The discovery of a second species of Litonotaster is one of the interesting
results of the work of the ALBaTRoss in the Tropical Pacific, for the genus was
hitherto known from only the deep waters of the West Indies, Koehler having
shown (1909. Investigator Ast., p. 73) that Aleock’s (1893. Ann. Mag. Nat.
Hist., (6), 11, p. 90) identification of an Indian starfish as identical with the
West Indian form was quite erroneous. The genus seems to be a very well-
marked one and the present species shows its distinctive characters perfectly.
But the differences between tumidus and intermedius, the genotype, are obvious,
particularly in the three following points: — in tumidus the abactinal plates
of the ray extend clear to the terminal plate while in intermedius this is not’ the
case, the distal superomarginals meeting in the radial line; in tumidus, the
abactinal plates of the distal part of the ray are more uniformly bare than in
intermedius; and finally, there are only four or five adambulacral spines in
tumidus as against seven or eight in intermedius.

The present species does not show a great deal of individual diversity except
in the body-form, already referred to, which is due to the amount of flattening
of the interbrachial are. The only growth-change noted is the greater granula-
tion of the abactinal plates in the adult. In the smallest specimens (R = 19
mm.) most of the disk-plates and those on the proximal part of the arms, as
well as the distal plates on the arms, lack granules on the surface, only the
marginal series being present. The madreporite is relatively, as well as actually,
very much smaller in the small specimens than in the larger.

86 ECHINASTERIDAE.

OREASTERIDAE.
Nidorellia armata.

Pentaceros (Nidorellia) armatus Gray, 1840. Ann. Mag. Nat. Hist., 6, p. 277.
Nidorellia armata Verrt1, 1867. Trans. Conn. Acad., 1, p. 280.

A single specimen with R = 85 mm. was brought back from Chatham
Island, Galapagos.

LINCKIIDAE.
Linckia guildingii.
Gray, 1840. Ann. Mag. Nat. Hist., 6, p. 285.
A small “‘comet-form”’ Linckia, with the main arm 25 mm. long, and the

four small arms 8-10 mm., taken at Papeete, Tahiti, seems to be the young of
this species.

Pharia pyramidata.

Ophidiaster (Pharia) pyramidatus Gray, 1840. Ann. Mag. Nat. Hist., 6, p. 284.
Pharia pyramidata SLADEN, 1889. Challenger Ast., p. 784.

There are three specimens of this common Panamie species from Perico
Island, Panama. They are remarkable for the short, stumpy appearance of
the arms, which are only about four times as long as thick. R = 90-95 mm.;
br. = 23 mm. Closer examination shows that not a single arm has a normal
tip but in every case the distal part is missing. Although the injury has healed
in each case there is no true regeneration started on any arm. It would be
interesting to know whether some fish is a persistent browser on this sea-star at
Perico Island.

ECHINASTERIDAE.

Henricia gracilis.

Cribrella gracilis Lupwia, 1905. Mem. M. C. Z., 32, p. 204.
Henricia gracilis Fisner, 1911. Bull. 76 U.S. N. M., p. 270.

Two very small Henricias(R = 10mm.) are as near to this species as to
any and are best regarded as young specimens thereof, particularly since one
of the original examples of gracilis was taken near the Galapagos Islands in
384 fms.

Station 4642. Galapagos Islands: Hood Island, 4 miles southeast of Ripple Point, 300 fms. Bott.
temp. 48.6°. Brk. sh., glob.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 87

PTERASTERIDAE.

Although there are only two specimens of this family in the collection,
their identification has necessitated a critical revision of the genus Hymenaster
and it has seemed worth while to publish this revision. The first reference to
the group in literature occurs in Wyville Thomson’s The Depths of the Sea,
published in 1873, but it was really the work of the CHALLENGER, in the same
and three subsequent years, which revealed what a wide-spread and character-
istic deep-sea genus Hymenaster is. Since that day numerous additional spe-
cies have been taken, until the number which have been named now reaches a
total of forty-four. The following list gives these species in their chronological
order with the necessary bibliographical references and the locality and depth
at which they were first taken.

List of the specific names used with Hymenaster.

pellucidus WyviLtE THomson, 1873. Depths of the Sea, p. 120. Faerée Channel, 580 fms.

nobilis WxvILLE THomsen, 1876. Journ. Linn. Soe. Zool., 13, p. 73. 1,099 miles southwest of Australia,
1,800 fms.

membranaceus WYVILLE THOMSON, 1877. The Atlantic, 1, p. 108.1 Off Portugal, 1,125 fms.

formosus SLADEN, 1882. Journ. Linn. Soc. Zool., 16, p. 213. 1,099 miles southwest of Australia, 1,800
fms.

pergamentaceus SLADEN, 1882. Ibid., p. 215. East of Buenos Ayres, 2,650 fms.

sacculatus SLADEN, 1882. Ibid., p.217. 1,099 miles southwest of Australia, 1,800 fms.

echinulatus SLADEN, 1882. Ibid., p. 218. Mid-South Pacific, 2,335 fms.

carnosus SLADEN, 1882. Ibid., p. 220. Off Chili, 1,500 fms.

glaucus SLADEN, 1882. Ibid., p. 221. Southwest of Suruga Gulf, Japan, 565 fms.

vicarius SLADEN, 1882. Ibid., p. 223. Between Juan Fernandez and Valparaiso, 1,375 fms.

infernalis SLADEN, 1882. Ibid., p. 224. Mid-North Pacific, 2,900 fms.

caelatus SLADEN, 1882. Jbid., p. 225. 1,099 miles southwest of Australia, 1,800 fms.

crucifer SLADEN, 1882. Ibid., p. 227. 1,099 miles southwest of Australia, 1,800 fms.

anomalus SLADEN, 1882. Ibid., p. 228. North of Tristan da Cunha, 1,425 fms.

latebrosus SLADEN, 1882. JIbid., p. 230. Southwest of Australia, 1,950 fms.

porosissimus SLADEN, 1882. Ibid., p. 231. Between Juan Fernandez and Valparaiso, 1,375 fms.

graniferus SLADEN, 1882. Ibid., p. 238. Between Marion and Crozet Islands, 1,375 fms.

geometricus SLADEN, 1882. Ibid., p. 234. Mid-South Pacific, 2,335 fms.

pullatus SLADEN, 1882. Ibid., p. 235. Southwest of Admiralty Islands, 1,070 fms.

coccinatus SLADEN, 1882. Ibid., p. 238. Between Marion and Crozet Islands, 1,375 fms.

praecoquis SLADEN, 1882. Ibid., p. 240.2 Near Crozet Islands, 1,375-1,600 fms.

modestus VERRILL, 1885. Amer. Journ. Sei. ser. 3, 29, p. 151.°. Off southern New England, 1,098-1,451

fms.

1 Jt is perhaps debatable whether there is an adequate description in connection with this first use
of the name, but as the points mentioned would probably distinguish the species from the only other
Hymenasters known at the time, it may be just as well to let the name continue to rest on Wyville
Thomson’s authority.

2 These eighteen species described by Sladen, as well as the three named by Wyville Thomson, are
fully illustrated in Sladen’s Challenger Asteroidea, issued in 1889.

3 It is doubtful whether this description is adequate. A much better one appeared in 1894, Proc.
U.S. N. M., 17, p. 277.

88 PTERASTERIDAE.

giganieus SLADEN, 1891. Proc. Roy. Irish Acad., ser. 3, 1, p. 696. Southwest of Ireland, 750 fms.
giboryi Perrier, 1894. Travailleur et Talisman Stell., p. 189. Between Azores and Europe, 2,218 fms.
rer PERRIER, 1894. Ibid., p. 1861 Eastern North Atlantic, 623-1,248 fms.

regalis VERRILL, 1895. Amer. Journ. Sci. ser. 3, 49, p. 203. Off southern New England, 1,374 fms.
regalis var. agassizii VERRILL, 1899. Trans. Conn. Acad., 10, p. 221. Off southern New England,

1,242 fms.
perspicuus Lupwic, 1903. Belgica Seesterne, p. 30. Antarctic Ocean, southwest of Alexander the

First Land, 222-250 fms. ;
quadrispinosus FisHER, 1905. Bull. U. S. Bur. Fish., 24, p. 315. Off San Diego, Cal., 1,059 fms.
platyacanthus Lupwic, 1905. Mem. M. C. Z., 32, p. 191. Panamic region, 1,359-1,572 fms.
purpureus Lupwic, 1905. Ibid. p. 194. Between Cocos Island, and Panama, 1,470 fms.
violaceus Lupwic, 1905. JIbid., p. 196. Southeast from Acapulco, Mexico, 1,877 fms.
gracilis Lupwie, 1905. Ibid., p.198. Panamic region, 1,321-1,771 fms.
pentagonalis FisHer, 1906. Hawaiian Starfishes, p. 1099. Hawaiian Islands, 289-334 fms.
roseus KOEHLER, 1907. Bull. Inst. Ocean., no. 99, p. 21. Eastern North Atlantic, 1,009-1,148 fms.
campanulatus Korner, 1908. Trans. Roy. Soc. Edinburgh, 46, p. 550. Weddell Sea, 1,410 fms.
densus KoEHurr, 1908. Ibid., p. 554. Weddell Sea, 2,620 fms.
edax Koruter, 1908. Ibid., p. 552. East of South Orkney Islands, 1,775 fms.
fucatus Korn.er, 1908. Ibid., p. 553.2 Weddell Sea, 1,410 fms.
alcocki Korner, 1909. Investigator Deep Sea Ast., p. 110. East side, Bay of Bengal, 643 fms.
koehleri Fisner, 1910. Ann. Mag. Nat. Hist., ser. 8, 5, p. 170. Bering Sea, 1,771 fms.
perissonotus FisHEr, 1910. - Ibid., p. 170. Off San Diego, California, 984 fms.
barischi FisHer, 1916. Proc. Biol. Soc. Washington, 29, p. 29. Sulu Sea, 1,105 fms.
rhodopeplus FisHER, 1916. Jbid., p. 29. Gulf of Tomini, Celebes, 834 fms.

The form which Verrill described as a variety (agassizit) of regalis seems
undoubtedly a valid species as it differs from regalis in several fundamental
points.

The characters which seem of the most importance in distinguishing the
species of Hymenaster are the armature of the oral plates and of the adambula-
cral plates. In most species the number of adambulacral spines, of oral spines,
and of suboral spines is remarkably constant. In a few cases, we find three
adambulacral spines where the typical number is two, or four where three is
usual, and if the number of oral spines is three, there may occasionally be four,
while if the number is usually four or five it may run up to seven. The number
and form of the suborals is less liable to diversity, but owing to slight shifts of
position or some diversity in size, it is often difficult to decide whether the spine
nearest the inner end of the oral plate is a suboral or the innermost oral. Careful
consideration of its relation to the other orals will generally determine the
point however. Thus in carnosus, Sladen says there are two suborals but
admits that the inner is perhaps an oral; his figure shows that it is best consid-
ered the innermost oral. In quadrispinosus Fisher, it is possible, as that author

___ + These two species of Perrier were named and the names were published in 1885 but with no descrip-
tion or figures; the names therefore must date from 1894.
* These four species of Koehler were mentioned and named in 1907, Zool. Anz., 32, p. 144, but as

the diagnoses are wanting or wholly inadequate, the names must date from the full report. The Hymen-
aster scotiae of the 1909 Zoological Record is a slip of the pen for Hyphalaster scotiae.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 89

says, that the innermost oral should be considered a suboral but I have not the
material to determine the point. In using the following key to the species of
Hymenaster, these possible variations in number of adambulacral, oral, and
suboral spines must be kept in mind and when there is any doubt both alterna-
tives should be followed out. The key includes not only all the species listed
above, but also the two new forms described below, each of which has some
very distinctive characters. Of course the accumulation of more material will
bring out defects in the present key, but it will serve as a beginning for a satis-
factory brief expression of the taxonomy of the genus. It will be noticed that
some of the characters which were considered of primary importance by Sladen,
such as the reticulation of the supradorsal membrane, and the body-form, are
here either ignored entirely or relegated to a very subordinate position. This
has been done because these characters vary so much with the condition of the
specimen, as to be of doubtful value. Most Hymenasters are secured only by
dredging or trawling in very deep water and they reach the surface in a more
or less contracted, contorted, and often damaged condition. It is therefore
often impossible to determine what the form and appearance in life were. Since
the caleareous parts are less likely to be altered by capture and preservation,
I have sought to use these as far as possible in distinguishing the species. Proba-
bly this leads to a more artificial arrangement than if all the characters could be
considered but under existing conditions any arrangement of the species of so
little-known a genus must be more or less non-phylogenetic.

Key to the species of Hymenaster.

A. Adambulacral armature of one spine.
B. Suboral spine single.
(Ce Oil Fakes", scodaceoberosaecudocooop hus soccucoduuccuR. aruoe EOS Umenons cremnodes.
CC. Oral spines 3 or 4.
D. Spiracula not in definite circumscribed areas, except for regular transverse bands on inter-
brachial membrane; oral spines nearly as long as jaws...............+.+.-.- nobilis.
DD. Spiracula in definite circumscribed areas but transverse bands on interbrachial membrane
replaced by small, detached, scattered areas; oral spines about half as long as jaw or

MOBS). Whtarcyal cy snenecrctart te eel ertens A Rd OCC COTO OR Oe aC OO nec Aap So. rra eto koehleri.
BB. Suboral spines 2 on each plate.
GENO pie ook vodd obuorcc tc: cob coaeduu ev cone. coOcoUad SUSnepednuanl cour formosus.

CC. Oral spines 3 or 4.
D.! Actinolateral membrane thin with very long actinolateral spines; spiracula very small

in widely, scatteredsexOups| Os OO err) ar-scltaleletletelale = lale- eles! «le al aari+ olnle pergamentaceus.
DD. Actinolateral membrane thick with short or moderately long actinolateral spines buried
in it; spiracula moderately large in irregular groups of usually more than 10.
ISL. geiflayergsll Kees) PYOEMEO Se Gon gob nao cp odd oS ODOR DOU ROR OOD ODO OOWOTDDE rhodopeplus.
HE. Suboral spines thick, stout, sacculate.-..........5...- essen ere eee reer violaceus,
AA. Adambulacral armature of more than one spine,

90 PTERASTERIDAE.

B.. No true suboral spines though the innermost of the 3 orals might be so considered......... trias.

BB.! Suboral spines present.
C2 No small marginal spines on oral plates.
D2. 3 large, subequal spines on each oral plate (all suborals or 2 suborals + loral)....... edazx.
DD. 2 large spines on each oral plate (both suborals or 1 suboral + 1 oral).
Et. Valves of osculum with 5 or 6 spines; paxillae with 5-8 spinelets; color yellowish white.
campanulatus.
EE. Valves of osculum with 10 spines; paxillae with 4 spinelets; color dark or at least dusky.
purpureus.
CC2 Marginal spines (orals), smaller than suborals, present on oral plates.
D.* Suboral spine single.
E2 Adambulacral spines 2; membranes fleshy; spiracula very small and grouped; orals 4-6.

F. Suboral spine like a segmental papilla.............-...-.----- -+---- pentagonalis.
FF. Suboral spine not like a segmental papilla.............-..---.---+------- carnosus.
EE2 Adambulacral spines more than 2.
F.! Rays attenuate, R = about 2r; adambulacral spines 3........-....... geometricus.
FF.) Rays not at all attenuate.
G. Orals 3, stout; third or fourth actinolateral spine longest............ coccinatus.

GG. Orals 4 or 5, slender.
H. Fifth or sixth actinolateral spine longest; adambulacral spines 3 or 4, not in a

continuous) series... 0.6 55d Fasck cee Been eee ee eee modestus.
HH. Seventh to eleventh actinolateral spines longest; adambulacral spines 4 or 5 in a
CONLIMUOUS SELICS!. ..<.c.c occ es leis ein ee Sree te teee een net One quadrispinosus.

DD.* More than one suboral to a plate.
E.° Suboral spines 2 on each plate.
F2 Only 2 adambulacral spines (3 on some plates, in perissonotus).
G2 Only 2 orals... 2.0... eect eee esndece 2 22] eee eee ene eee giboryi.
GG. 3 or more orals.
H.: Paxillar spinelets few, rarely more than 5, often 3.
I. Orals 3.
J. Actinolateral spines rather short, robust, eighth or ninth longest. . . echinulatus.
JJ. Actinolateral spines very long, twentieth to twenty-second longest.

giganteus.
II. Orals 4~7.
J. Of actinolateral spines, fifth to twelfth longest.
K. More or less pentagonal; paxillar spinelets 4 or 5; orals4......... TOseus.
KK. More or less stellate; paxillar spinelets usually 3; orals5........ agassizii.
JJ.1 Of actinolateral spines, twelfth to twenty-first longest.
K.! Of actinolateral spines, twentieth or twenty-first longest...... sacculatus.

KK. Of actinolateral spines, eighteenth or earlier longest.
L. Paxillar areas of rays conspicuously elevated; actinolateral spines short,

StOUE 20. a,c cans sos OS ans ole os eo ae Eee ae eee glaucus
LL. Paxillar areas not conspicuously elevated; actinolateral spines long,
slender.
M. Paxillar spinelets 3 or 4; on some plates, 3 adambulacral spines.
perissonotus.
MM. Paxillar spinelets 4-6; only 2 adambulacral spines........ vicarius.
HH. Paxillar spinelets many, 5-12.

I! Paxillar spinelets 5-7............ 30s bbl te ee Oe pellucidus.

II! Paxillar spinelets 8-12.
J? Form pentagonal... 2.225% 34.2.0 02%. 02-2 eee a eee perspicuus.
JJ? Formistellate. .2cios% 6 00 sj. 5 «ieiec sot ee eee infernalis.

FF? More than 2 adambulacral spines, except on individual plates or near tip of ray.
G2 Color deep purple, with fibrous bands in supradorsal membrane and tips of tube-
feet, white; adambulacral spines 3, short, thick subequal............- pullatus.
GG Not as above.
H? Orals 2; paxillar spinelets 5-7; adambulcral spinelets 3-5; fifth actinolateral
spine longest .\./..<.<:.) ace cee «os foe con cies See eee praecoquis.

* Sladen’s figure shows 4 oral spines but in his description he distinctly says there are only two.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 91

HH Orals 3-5.
I. Paxillar spinelets 4-7; valves of osculum with 15 spines; actino-
lateral spines 18, with eighth or ninth longest; adambulacral
spines usually 3, the innermost smallest, but sometimes 4, the 2
INNET AMA EN Goer tere ctacta iielstereie aise aes lee eee Raa T Cases Se aereate gracilis.
Il.2 Not as above.
J. Adambulacral spines 3.
K Orals only 3.
L.1 Valves of osculum duplicated by a smaller external series...... alcockt.
LL. Valves of osculum not duplicated.
M.! Paxillar spinelets 4 or 5.
N. Paxillar crowns forming raised areas and sharply defining the rays.

caelatus.

NN. Paxillar crowns not forming raised areas and not defining rays
Cleary Asie obverse: ois eis evs oe ae, faye 0) a1 ore Si imp areteye aces latebrosus.

MM.! Only 1 well-developed paxillar spinelet...................- regalis.

KK. Orals more than 3.
L.2 Suborals short and wide (or thick).
M.* Adambulacral spines very unequal; supradorsal membrane with

numerousuminute pranules’ = coc ss-. 5-5 siete scissile graniferus.
MM. Adambulacral spines subequal; supradorsal membrane without
pranules 73325. Osc jee i ie tier ts patie ne cmeatas membranaceus

LL. Suborals more or less elongate and tapering.
M.* Adambulacral spines very unequal; rays conspicuously defined

MM.* Adambulacral spines subequal.
N.1 Tenth to seventeenth actinolateral spine longest.
O. Inner (proximal) pair of suborals the longest.
P. Orals 4 subequal; outer suboral stouter than inner, shorter

butimot: greatly, soe a2 ee sete = foe iri- cic mmeis ers bartschi.
PP. Orals 5, the two inner ones much larger; outer suboral much
smaller in every way than inner............ porosissimus.
OO. Outer (distal) pair of suborals much the longest....... crucifer.
NN. Sixth actinolateral spine longest; suborals subequal..... . fucatus.
JJ.?- Adambulacral spines 4.
14s Paxillan spimeletsia—os OFals! 4: seas ce cin bayer ste sees = le platyacanthus.
KK 2 Paxillarspmecletsyo—Gs, OFAIs or reser etoteciets eels Sadat som ees densus.
EE:*' Suboral. spines'3 onyeschi plate: 5. 22.22% 2s asOee oc spctse secs ee week anomalus.

Hymenaster cremnodes,' sp. nov.

Plate 4, fig. 1.

Rays 5. R= 27 mm.; r= 24 mm.; R= 1.125 r. In its present con-
tracted bell-shape, the specimen is nearly 27 mm. high and about 18 mm. in
diameter at the mouth of the bell. Paxillae in three series along each ray with
an additional partial row along each side of base of ray. Paxillar spinelets
5 or 6 rather long, longer than stalk of paxilla; each spinelet has a thickened
cap of skin over its tip, these caps forming conspicuous little blunt cones all over
the dorsal surface. Spiracula numerous, rather large, irregularly scattered.
Osculum large, about 10 mm. across; each valve with about a dozen spines,

1 kpnuvadns = steep, in reference to the remarkable form of the jaws.

92 PTERASTERIDAE.

which are clothed, distally at least, with thick opaque skin; the middle spies
are about twice as long as the most lateral. In each interradius is a notch about
a millimeter deep, on each side of which the interbrachial membrane forms a
slightly convex lobe well-supported by the actinolateral spmes whose distal
ends are covered with thick opaque skin. The triangular interbrachial area is
about 10 mm. deep (along the interradius) and in its present contracted condi-
tion about 6-8 mm. wide along the free margin. Actinolateral spines about
fifteen, of which the third or fourth seems to be the longest; the thick skin in
which the spines are somewhat imbedded and the shape and condition of the
specimen prevent exact determination of these pomts. Adambulacral armature
consists of a single, acicular spine, about 3 mm. long and not at all sacculate.
Aperture papillae nearly sessile, rounded triangular, not as wide as high and
scarcely one third the length of the adambulacral spine. Oral plates fused to
form a jaw whose length, breadth, and height (distally) are about equal; the
slope from the distal end of the keel to the inner tip of the jaw is exceptionally
steep; the breadth of the whole jaw, distally is probably considerably more
than the height but this is hard to determine; on the outer distal corner of each
oral plate are two slender oral spines 1.5—2 mm. long and just below the middle
of the surface of each plate is a suboral spine about 3 mm. long and very similar
to the adambulacral spines; none of these spines is at all sacculate. Color of
supradorsal membrane dull bluish except where it is thickened over the tips of
spinelets and spines; in such places it is yellowish white; oral surface nearly
black except the interbrachial membrane between the tips of the rays which is
contrastingly yellowish white.

Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 35’ 36” W., 2,370 fms. Bott. temp. 35.3°. Fne,
gn. m., mang. nod.

One specimen.

It is difficult to determine how much of the extraordinary bell-shape of
this curious Hymenaster is due to contraction caused by its capture and preserva-
tion. The bell is much deeper and narrower than in Koehler’s campanulatus
and the rays do not project noticeably beyond its margin. If this were the
normal form of the animal in life, the tube-feet on the proximal half of the rays
would be useless; indeed progression would have to be by swimming freely in
the water. It is very probable that the form of the preserved specimen is quite
unnatural and is due to extreme contraction of the interbrachial areas especially
along their margins. The armature of the adambulacral and oral plates is very
distinctive and the coloration is also peculiar, the heavy pigmentation of the

EASTERN TROPICAL PACIFIC ASTEROIDEA. 93

oral surface being quite unusual. The very high and steep jaws are no less
remarkable, so that entirely apart from the peculiar shape the species will be
easily recognized when next it is taken.

Hymenaster trias,! sp. nov.

Plate 3, fig. 1, 2.

Rays 5. R=40 mm.; r= 28 mm.; R= 1.43 r. Body highly arched,
the vertical diameter at center being about 20 mm. but this may be due in part
to marginal contraction. Form distinctly stellate, the interbrachial arcs being
rather deep and angular. Rays quite acuminate, the free narrow tip, about
8 mm. long, being turned up against the aboral surface of the ray. Paxillae
covering the whole dorsal surface, the interbrachial areas, as seen from above,
practically wanting. Paxillar spinelets five to eight usually six, longer than
stalk, very slender and projecting through the thin supradorsal membrane for
nearly or quite half their length. Spiracula fairly numerous, quite large, irregu-
larly scattered. Osculum large, about 10 mm. across; each valve with twelve
to fourteen spines of which the outermost are shortest but are about three fourths
or at least two thirds as long as the middle ones. Actinolateral spines few and
widely spaced; there are about sixteen of which the fifth is longest. The mem-
brane in which they lie is thin and transparent. Adambulacral armature con-
sists of two well-spaced, subequal, slender, brittle spines, 4-5 mm. long; the tip
is blunt and the spines are not at all sacculate. Aperture papilla distinctly
stalked, the blade about as wide as high, except that the upper margin has more
or less of a membranous extension, which is, however, never very great. Oral
plates united to form a very wide jaw, the width being considerably more than
twice the length; the median keel is quite conspicuous but slopes gradually to
the inner tip which is wide and rounded; each plate carries three oral spines, of
which the innermost is as long as the jaw, or longer, and stands a trifle back
from the margin and the outermost is about two thirds as long and stands on
the margin near the outer proximal corner of the plate; the middle spine is
intermediate in size and position. There is no suboral spine. None of the
spines are sacculate. Color, both above and below,:pale yellowish.

Station 4672. Peru: southwest of Palominos Light House, 88 miles, 2,845 fms. Bott. temp. 35.2°.
Fne. dk. br. infus. m.

One specimen.

1 rp.as = three, in reference to the armature of the oral plates.

94 ZOROASTERIDAE.

The absence of any suboral spines distinguishes this species from any
hitherto described. The three oral spines are so perfectly graduated in size
and position, it would be quite unnatural to call the innermost a suboral, even
though its position is not strictly marginal. Other notable features of this form
are the greatly projecting pavxillar spinelets, the few, slender, and widely spaced
actinolateral spines, and the very long and slender adambulacral spines.

ZOROASTERIDAE.!

The systematic position of this small but well-marked family has been
the source of no little difference of opinion, but few will now question the posi-
tion assigned it by Verrill and by Fisher in the Forcipulosa near the Asteriidae.
More than thirty species have been assigned to Zoroaster but the remaining
genera are either monotypic or contain only two or three species. As I have
had occasion to study critically the forms referred to Zoroaster, I give here a
list of such species, followed by artificial keys to the genera which it seems
desirable to recognize, and to the species which they contain, when not mono-

typic.
List of the specific names used with Zoroaster.

fulgens Wyvitte Tomson, 1873. Depths of the Sea, p. 154. Northwest of the Hebrides, 767 fms.2

sigsbeei * Perrrer, 1880. Comp. Rend., 91, p. 436. Off St. Kitts, B. W. I., 120-231 fms.

ackleyi Perrier, 1880. Ibid.

diomedeae VERRILL, 1884. Amer. Journ. Sci., ser. 3, 28, p. 217. Off southern New England, 1,000-1,600
fms.

longicauda Perrier, 1885. Ann. Sci. Nat., ser. 6,19, no. 8, p.19. Eastern North Atlantic, 1,637-2,325
fms.

tenuis SLADEN, 1889. Challenger Ast., p. 421. North of New Guinea, 1,070 fms.

alfredi Aucock, 1893. Ann. Mag. Nat. Hist., ser. 6, 1, p. 102. Bay of Bengal, 1,300-1,380 fms.

barathri Aucock, 1893. Ibid., p. 103. Bay of Bengal, 1,520 fms.

planus Aucock, 1893. Ibid., p. 104. Laccadive Sea, 1,200 fms.

angulatus Aucock, 1893. Ibid., p. 105. Gulf of Manaar, 597 fms. Laccadive Sea, 705 fms.

carinatus AucocK, 1893. Ibid., p. 107. Andaman Sea, 130-250 fms.

gilesii Aucock, 1893. Ibid., p. 108. Andaman Sea, 400-500 fms.

squameus Aucock, 1893. Ibid.,p.109. Laceadive Sea, 1,043 fms.

zea Aucock, 1893. Ibid.,p.110. Gulf of Manaar, 597fms. Laccadive Sea, 1,200 fms.

trispinosus KOEHLER, 1895. Rev. Biol. Nord France, 7, no. 12, p.6. Bay of Biscay, 360 fms.

ophiurus Fisner, 1905. Bull. U. 8. Bur. Fish., 24, p. 315. Off San Diego, Cala., 1,059 fms.

‘Since this report was prepared, Fisher has published two important papers bearing on the mor-
phology and taxonomy of this family: 1919, Ann. Mag. Nat. Hist., ser. 9, 3, p. 387-393; 1919, Bull. 100
U.S. N. M., p. 470-487. As our results have been reached quite independently and are almost invari-
ably in accord, I have let this account of the Zoroasteridae stand with very few changes.

* An unfortunate typographical error on p. 152 gives this locality as ““2°.11’ W. long.” On p. 144
however, it is correctly given as “9° 11’ W.”

* The name is spelled “Sigsbeci” in the original publication but this is, of course, a typographical error.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 95

sacculatus FisHer, 1905. Ibid., p.316. Monterey Bay, Cala.,916fms. See Myxoderma.

evermanni FisHerR, 1905. Ibid., p. 317. Between San Diego and’San Clemente Island, Cala., 500-507
fms.

magnificus Lupwic, 1905. Mem. M. C. Z., 32, p. 159. Gulf of Panama, 1,671 fms.

nudus Lupwia, 1905. Tbid., p. 164. Gulf of California, 998 fms.

hirsutus Lupwia, 1905. Ibid., p. 172. South of Acapulco, Mexico, 1,878 fms.

longispinus Lupwtie, 1905. Ibid., p. 180. Eastern Tropical Pacific, 780—1,320 fms.

spinulosus FisHeR, 1906. Bull. U.S. Fish Comm., 1903, p. 1102. Hawaiian Islands, 328-557 fms.

bispinosus KoEBLER, 1909. Princesse-Alice Ech., p. 316. No locality given.

adami Korner, 1909. Investigator Deep Sea Ast., p. 108. Bay of Bengal, 569 fms.

platyacanthus H. L. CuarK, 1913. Bull. Amer. Mus. Nat. Hist., 32, p. 199. Off west coast of Lower
California, 284 fms.

ophiactis Fisher, 1916. Proc. Biol. Soc. Wash., 29, p.29. Gulf of Tomini, Celebes, 834 fms.

maicroporus FisHer, 1916. Ibid., p. 30. Southwest of Amblan Island, Moluccas, 700 fms.

carinatus philippinensis FisHEeR, 1916. Ibid., p. 30. Sibuko Bay, Borneo, 415 fms.

macracantha H. L. CuarK, 1916. Endeavour Ech., p. 68. Great Australian Bight, 250-450 fms.

actinocles FisHer, 1919. Ann. Mag. Nat. Hist., ser. 9, 3, p. 390. Aleutian Islands, 1,217 fms.

evermanni mordax FisHer, 1919. Ibid., p. 390. Off Washington, 477 fms.

Of the above species, tenuis and longispinus are based on very young speci-
mens, in which the real specific characters are as yet undeveloped. It is useless
to attempt to compare them with the adults of other species and they are there-
fore omitted from the keys. Until adults are collected, accompanied by young
and intermediate stages, these two names are of little service. Ludwig (1905.
Mem. M. C. Z., 32, p. 177) has described another young Zoroaster but he re-
frained from giving it a name. Koehler’s record (1908. Scotia Ech., p. 566) of
tenuis from 1,742 fms. in the extreme South Atlantic Ocean merely shows that
the genus ranges that far south. It is highly improbable that his specimen is
conspecific with Sladen’s type of tenuis. Of course, bispinosus is only a slip
of the pen for trispinosus.

The remaining twenty-nine species include several groups which seem to be
worthy of rank as distinct genera. First of these is Mammaster, proposed by
Perrier in 1894 (Travailleur and Talisman Stell., p. 125) with Z. sigsbeei as the
type. There is little doubt that the genus is very nearly related to Cnemidaster
as that group now stands, thanks to Fisher’s investigations (1919. Bull. 100 U.S.
N. M., p. 480-484). But I do not think it will ever be necessary “to merge
the two genera” as Fisher suggests. For there is a rather striking character,
hitherto apparently overlooked, which distinguishes Mammaster at once from
any of the known species of Cnemidaster. This is given below in the key to
genera and while it may not be of great morphological importance, it affects
very evidently the general appearance of the disk. The ALBarross collections
in the Philippines have revealed so well the growth-stages of Cnemidaster that
we can now delimit that group of East Indian and Pacific species very well.

96 ZOROASTERIDAE.

While Mammaster remains monotypic, the following species are to be referred
to Cnemidaster: — wyvillei, squameus, zea, nudus.

At the same time that he proposed Mammaster, Perrier also seems to pro-
pose a new genus, Prognaster, with Z. longicauda as the type. He had however,
three years earlier (1891. Mem. Soc. Zool. France, 4, p. 259) given the same
name and diagnosis to a genus with a new species, grimaldi, as the type. This
earlier publication of the name is only referred to casually and ambiguously in
the later paper, the user of the Travailleur and Talisman Report being thus
completely and quite needlessly misled. The discovery of the many long-
armed Zoroasters of the Indian Ocean has made the proposed genus as repre-
sented by longicaudus quite untenable and I am not able to find any satisfactory
basis for separating that species from the more typical species of Zoroaster.
But if Perrier is correct in his statement regarding grimaldi that the adambula-
cral plates are all alike, the genus Prognaster may well be retained for so unique
a zoroasterid.

In 1905, Fisher (Bull. U. 8. Bur. Fish., 24, p. 316) proposed a subgenus
Myxoderma for two new Zoroasters, sacculatus and evermanni, designating
sacculatus as the type. This group, to which platyacanthus H. L. Clark also
belongs, is well-characterized and Fisher has recently (1919. Ann. Mag. Nat.
Hist., ser. 9, 3, p. 387) given it full generic rank. But evermanni proves to be
a true Zoroaster. Another genus described by Fisher (1916. Proc. Biol. Soe.
Washington, 29, p. 31) is Bythiolophus, based on material collected by the
Aupatross in Buton Strait, Celebes. This seems to be quite distinct from
anything hitherto known in the family. Finally mention must be made of
Sladen’s (1889. Challenger Ast. p.426) genus Pholidaster, recently rediscovered
by the ALBATROSS.

There are then seven apparently valid genera of Zoroasteridae.

Key to the genera of Zoroasteridae.

A. Primary plates and usually additional disk-plates conspicuously large, convex (often swollen),
and more or less bare.

B. First carinal plate, just distal to primary radial, conspicuously enlarged, larger than the adjoin-
ing second marginals which are very much larger than the first ones; adradials wanting; three
series of actinolaterals with beginnings of a fourth in large specimens........ Mammaster.

BB. First carinal scarcely or not at all larger than the first marginals which are evidently larger than
the second; adradials present; four or five series of actinolateral plates...... Cnemidaster.
AA. Disk-plates not conspicuously convex or swollen, or if so, closely covered with spinules.
B Adambulacral'plates‘all alike: < 2o..5.02h..0. sesso ee once Prognaster.
BB.‘ Every other adambulacral plate with a conspicuous ridge projecting into furrow and carrying
long spines.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 97

C. Carinal plates of ray smooth and bare surrounded by series of skin-covered squamules.
Pholidaster.
CC. Carinal plates not surrounded by series of skin-covered squamules.
D. A conspicuous buttress (a specialized superambulacral plate) connects first two ambulacral
plates with body-wall; superambulacral plates present.

E. Adradial plates present; superomarginals not overlapping carinals......... ./ Myxoderma.

EE. Adradial plates wanting; superomarginals strongly overlapping and dominating the

GALINAIS; «2.5.12 ce eee eC ers Moen ee ee Ae Ree Serie a ale ais ote Bythiolophus.

DD. Superambulacral plates wanting, and hence no buttresses between ambulacral plates and

Dod yewallll «., <5): <.cceautern seta Seen rete auctor enya ern afez Bier omegevevekove cer sycawe haa ake Smit tee Zoroaster.
Mammaster.

PERRIER, 1894. Travailleur et Talisman Stell., p. 125.
Type-species: Zoroaster sigsbeet PERRIER, 1880. Comp. Rend. 91, p. 436.

This genus is still monotypic, for the allied East Indian species all differ in
the character of the marginal plates at the base of the arms. Aleock (1893. Ann.
Mag. Nat. Hist., ser. 6, 11, p. 111) considers three of his eight Zoroasters con-
generic with szgsbeei, but he failed to note this particular feature which seems
of no little importance. Fisher makes no reference to it and hence it does not
seem to have attracted his attention. His work has shown that Alcock’s three
species are Cnemidasters but he is not sure that Mammaster can be maintained
as distinct from that genus. Mammaster is evidently not common as I have
found no published records of its occurrence other than those in the BLAKE
Report — one station near St. Christopher in 208 fms. and one in the Gulf of
Mexico is 321 fms.; seven specimens altogether. The largest of the BLAKE
specimens had R about 75 mm. Perrier selected a much smaller specimen
(R = 49 mm.) for his description and does not refer to the large one.

CNEMIDASTER.

SLapEN, 1889. Challenger Ast., p. 423.
Type-species: C. wyvillii SuapEN, 1889. Loc cit. Monotypic when established.

The collections made by the ALBaTrRoss in the Far East have enabled Fisher
to revolutionize our knowledge of this genus, which was based on a single very
immature specimen. Fisher had seven specimens at his disposal and has been
able to make clear some of the growth-changes. These bring out the impor-
tant fact that the Zoroasters described under the names nudus, sywameus, and zea
are all congeneric with wyvillii. Indeed the four species are so closely related,
it is exceedingly difficult to separate them properly. The following key is the
result of studying cotypes of nudus and squameus, and the descriptions and

98 ZOROASTERIDAE.

figures of zea and wyvillii published by Alcock, Sladen, and Fisher. But as I
have not seen a specimen of either of these last two forms, which Fisher intimates
may be identical, I consider the number of valid species in Cnemidaster still

uncertain. I think nudus is undoubtedly distinct from the East Indian forms

but the three latter are certainly very closely allied.

Key to the species of Cnemidaster.

Spinelets of actinal surface with thin sacculation scarcely noticeable when dry, not covering the plates

very closely.

Distal earinals, and often marginals, with a central spine about as long as plate........... wyvilliz.

Distal carinals and marginals unarmed, but often with one or more minute spinelets or elongated

PT AMUES 85 <a ecw everce ove cre eel aha e 2s wee ee ss ch sree oxen PSI foge eke Re nudus.

Spinelets of actinal surface flat, more or less squamiform, with heavy sacculation, closely covering the
plates.

Intermarginal papulae present; adambulacral ridge (on each alternate plate) with three stout spine-

lets) 29. cece it Ste eine oho oe bw cowie d oo cee eM Se ae Oe eee eee squameus.

Intermarginal papulae wanting; adambulacral ridge “bearing a row of three sabre-shaped spines

and deep within the furrow.a slender'spinelet?? =. <. ome = eielete rele etter ieneteeeee zea.

Prognaster.

Perrier, 1891. Mem. Soc. Zool. France, 4, p. 259.
Type-species: P. grimaldii Perrier, 1891. Loc. cit.

Perrier, in his later, fuller account (1896. Hirondelle Stell., p. 22), says
very emphatically that so far as he could see the adambulacral plates all extend
equally into the furrow. This is so unusual a character for an adult zoroasterid
that one can but suspect that Perrier has failed to examine the adambulacral
margin with sufficient care. If he is correct, the genus is easily recognizable.
The only known species was taken by the Prince of Monaco, near the Azores,
in 1,568 fms.

Pholidaster.

SuapEN, 1889. Challenger Ast., p. 426.
Type-species: P. squamatus SLADEN, 1889. Loc cit.

Although Sladen published a short notice of this genus in 1885, he mentioned
no species and hence the name must date from 1889. He never designated a
type but Fisher (1919. Bull. 100 U. S. N. M., p. 484) has done so. The two
known species were taken in the East Indian region: — squamatus in the Philip-
pines in 100 fms. and distinctus in the Banda Sea in 140 fms. The ALBATROSS
took squamatus at five stations in the Philippines in 108-218 fms. These are
all remarkably slight depths for a member of this family.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 99

. Key to the species of Pholidaster.

Superomarginals and most of the disk-plates concealed by flat, skin-covered seales.......... squamatus.
Superomarginals and primary disk-scales largely bare.................2200..-2000000-- distinctus.
Myxoderma.

Fisuer, 1905. Bull. U.S. Bur. Fish., 24, p. 316, as a subgenus of Zoroaster.
Type-species: M. sacculatus FisHer, 1905. Loc. cit.

This small group of sea-stars occurring off the coast of the western United
States and Lower California in 284-916 fms. is well-cirecumscribed and Fisher
has wisely (1919. Ann. Mag. Nat. Hist., ser. 9, 3, p. 392) raised it to full generic
rank. In the same paper he has described a subspecies of each of the two com-
ponent species but I doubt whether sufficient material has yet been secured to
warrant recognition of subspecies. In any case, however, he has set forth so
well the characters of these supposed subspecies in his key, that we need not dis-
cuss them here. There are certainly two valid species.

Key to the species of Myxoderma.

Spines and spinelets more or less conspicuously sacculate; big pedicellariae in ambulacral furrow or on
adambulacral spines; papulae in adults 3-5 in an area on base of rays abactinally. . . . sacculatum.
Spines and spinelets little or not at all sacculate; no big pedicellariae in furrow or on adambulacral spines;
papulae 1 or 2 in an area on base of rays abactinally.......................... platyacanthum.

Bythiolophus.

Fisuer, 1916. Proc. Biol. Soc. Wash., 29, p. 31, 1919. Bull. 100 U.S. N. M., p. 484, pl. 135, fig. 1—Ic,
139, fig. 1, 2.
Type-species: B. acanthinus Fisher, 1916. Loc. cit.

This monotypic genus is based on a single sea-star taken by the ALBATROSS
in Buton Strait, Celebes, in 559 fms. It is unquestionably a well-marked and
noteworthy type. In the diagnosis as published in 1919, the presence of sub-
ambulacral plates is mentioned; Dr. Fisher assures me this is a slip for super-
ambulacral. In the key to genera of Zoroasteridae (1919, p. 471) Bythiolophus
is said to have no adradial plates and in the figures 1 and le, pl. 135, as well as
in the explanation of the plate, the series of plates adjoining the carinals on
each side is called the superomarginal. But in the diagnosis of the genus (p. 484)
and in the diagnosis and description of the species (p. 485) this series is consid-
ered as adradial and the prominence of the adradial plates is emphasized. Dr.
Fisher writes me that the key was prepared much later than the text and is

100 ZOROASTERIDAE.

correct. There are no adradials. ‘‘The prominent plates immediately adjacent
to the carinals and overlapping them are almost certainly the superomarginals.

_.There are therefore on each side of the carinals 2 series of marginals and
5 actinolateral series. ‘The superomarginals are alternately larger and smaller.”

Zoroaster.

Wrvitte THomson, 1873. Depths of the Sea, p. 154.
Type-species: Z. fulgens WyVILLE THOMSON, 1873. Loc. cit.

Even as here restricted, this genus contains twenty-two species, and two
subspecies. It is no easy matter to separate them from each other, for the
specific characters are not numerous and several are very ill-defined, so that
even when species look as unlike as fulgens and longicaudus it is not easy to
express their differences briefly with reliable accuracy. So little is known of
growth-changes in the genus, it is quite likely the key given below will prove of
little use with young specimens. The condition of the adradial series of plates
furnishes the most important divisional character as it usually shows relatively
little growth-change, and yet in ackleyi at least, it is well-marked in specimens
with R = 50 mm. and quite concealed when R = 100 mm. The character and
degree of armature of the carinal and superomarginal plates furnish good but
less reliable features, and the tuberculation and spinulation of the actinolateral
plates are of some service. But the relative length of arm increases more or
less considerably with age and consequently body-form and proportions are not
reliable, while the armature of the adambulacral and oral plates shows relatively
little diversity in the genus. Nevertheless specific lines can be drawn with more
or less accuracy and the following key will help to differentiate the species. It
includes the new species described below, as well as the subspecies named by
Fisher.

Key to the species of Zoroaster.

A. Adradial series of plates well-developed at least on basal half of ray.
B. Superomarginals, some or all, armed with a central spine.
C. Most skeletal plates, except some or all adradials, with a stout central spine.
D. Abactinal plates nearly or quite without spinelets..................-.------ perarmatus.
DD. Abactinal plates well-covered with spinelets.
E. No large pedicellaria regularly on second spine of projecting adamibelaeca plates.
evermannt.
EE. A huge pedicellaria on second spine of each projecting adambulacral plate.
evermanni mordaz.
CC. Most skeletal plates without a central spine.
D.* Carinal plates wider than long; superomarginal spines irregularly developed, often wanting
on most of the plates.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 101

E. Armature of actinolateral plates with a central, slender spine longer than its fellows.
F. Fourth actinolateral series of plates present; superomarginal spines not much more

slender than carinal spines; spinelets scarcely fleshy...........-..---.-- fulgens+
FF. Fourth actinolateral series rudimentary; superomarginal spines decidedly more slender
than those on carinals; spinelets fleshier..............------.-++.--- actinocles

EE.! Armature of actinolateral plates with a trio of subequal spines longer than the others.
trispinosus.
DD. Carinal plates as long as wide or longer; superomarginal spines usually well-developed and
often forming, conspicuous SereS....-- 02-22-2225. - eee eee e een e ene diomedeae.

BB. Superomarginal plates unarmed.
C.1 Carinal plates unarmed.
D2 Covering of skeletal plates a close capillary spinulation.
E2 Intraambulacral ridge (of alternate adambulacrals) with two spines, the outer with a
huge pedicel arteyyat ilps easiest a ae dadote rere te teteae eal barathri.
EE2 Intraambulacral ridge with three or four spines and no huge pedicellaria... .ackleyi Juv.
DD Covering of skeletal plates made up of fine granules, little elongated; intraambulacral
ridge with one spine and no huge pedicellaria..........--..--.++-eeee eee eeee adami.
CC. Carinal plates armed with a more or less conspicuous central spine.
D.* Actinolateral plates with a conspicuous central spine-bearing tubercle.
E.2 Each adambulacral plate with two bunches of pedicellariae high up in furrow. . . .alfredi.
EE.* No such bunches of pedicellariae.
F. Rays strongly carinate; innermost adambulacral spine with a terminal tuft of about .
Pen pedicel arise steerer eset rie caterer aiseke eters oe ake! el sirieis in) neo eresefo rots ophiactis.
FF. Rays not strongly carinate; innermost adambulacral spine with four to eight pedicel-
lariae near tip.
G. Disk-plates unarmed; rays very long, slightly swollen at base and then tapering
steadily to a slender tip RA = 18-20 Tae ee es cae eee magnificus.
GG. Primary plates of disk armed with a central spine.
H. Disk and arm-bases more or less depressed; non-projecting adambulacral plates

VAAN TIN, (nee) steno a RGoonopanSrqselous+ dee odbocEaberocdoe planus.
HH. Disk and arm-bases not depressed; non-projecting adambulacral plates with
least Spite isn Sooroeboopesegdcoe sade oe oma Soneoebaneree hirsutus.

DD.* No conspicuous tubercle near center of actinolateral plates though one tubercle may be
somewhat larger than others. g
E4 R =16-18r; arms slender and tapering; no huge pedicellariae on adambulacral plates.

longicaudus.
EE! R = 10-15r; arms stouter and less tapering; huge pedicellariae present on adambulacral
iUM Mae Samm como aod ocde cod ocdac soos ets aecoescopMe oe onuosonass spinulosus.

AA. Adradial series of plates more or less reduced or wanting, their place often occupied by a con-
spicuous groove (sulcus) on each side of carinal series of plates.

B. Disk large, low, very distinctly delimited from rays by a ring of massive, semiglobular plates;

primary plates all massive and semiglobular; all plates covered with capillary spinelets with a

ity Gina Gomes mnienyieses| 45 codeneoons een ocoongoeges Sooner coooneesscae gilesit.
BB.! Disk not as above.
C2 Superomarginal plates conspicuously armed with a central spine............ macracanthus.

CC2 Superomarginal plates practically unarmed.
D.A Adambulacral plates with two transverse series of actinal spinelets.
E.5 Carinal plates armed, deeply notched on both sides...............-....-- angulatus.
BE >) Carmal plates unarmed. Sqm anish rect esate eleseietain clits) ie he stale microporus.

1 The figures given by Sladen (Challenger Ast., pl. 66) purporting to be fulgens are almost certainly
diomedeae, for Sladen called all the western Atlantic specimens fulgens; his description too seems to have
been made from the American form. This unfortunate state of affairs is misleading and may be why
Koehler considered his Bay of Biscay specimen a new species (trispinosus) instead of referring them to
fulgens. The differences between trispinosus and Sladen’s fulgens are evident, but comparison of Koeh-
ler’s descriptions and figures with a true fulgens leads one to suspect they are identical.

2 As Fisher’s description is brief and comparative, I am not sure that my summary of the distin-
guishing features will prove reliable.

102 ZOROASTERIDAE.

DD.‘ Adambulacral plates with only one transverse series of actinal spines. ;
E.® Abactinal surface with coarse spinulation and numerous big pedicellariae. .. .ophiurus.
EE. Abactinal surface with fine spinulation and few inconspicuous pedicellariae.
F2 Carinal plates at base of arm quadrilateral much wider than long; superomarginals
similar but smaller... -: 2... 02 --2 esses oe see eli eine rere ackleyi adult.
FF2 Carinal plates about as long as wide with lateral margins more or less deeply notched;
superomarginals irregularly diamond-shaped with rounded angles, not much wider

than long. :
G2 Adambulacral furrows with few pedicellariae.........-.------++++++5 carinatus.
GG. Adambulacral furrows with many pedicellariae.......... carinatus philippinensis.

Zoroaster perarmatus,’ sp. nov.

Plate 4, fig. 2.

R = 98 or 125 mm.; r= 13 or 18 mm.; R=7-7.5r. Disk moderately
large, not elevated above nor distinctly set off from rays. Primary plates
distinguishable but not conspicuous and not at all swollen. Rays rather stout,
the height at base equalling or exceeding the width, which is about .15-.17 of the
length; rays tapering to a blunt tip, more slender in the larger specimen than in
the smaller. Carinals moderate, wider than long, lateral margins narrowed
by large papular areas. Adradial plates moderately well-developed, at least on
basal part of arm, much longer than wide and nearly quadrilateral. Supero-
marginals similar to carinals but only about half as large. Inferomarginals
similar but somewhat smaller and relatively longer. Actinolaterals in four
series (on basal part of arm), nearly square and closely joined, the papular pores
being very small. There is no indication of imbrication among either the
marginal or actinolateral plates. Madreporite 2-3 mm. across, rather prominent,
close to disk-margin, surrounded by five or six spinelets.

The great majority of the skeletal plates are more or less elevated at or
near the middle into a conspicuous spine-bearing tubercle; the spine on the disk-
plates, carinals, marginals, and adradials being stout and erect, .75-2 mm.
high and .30—.90 mm. thick at base; on the actinolaterals the spine is often
wanting but when present reaches a length of 5 mm. and a thickness of 1 mm.
at base; in the smaller specimen, the spines are all erect, standing out at right
angles to the plate-surface, but in the larger specimen, the actinolateral spines
are all more or less appressed to the sides of the ray. On the disk-plates, carinals,
adradials, and marginals, there are no secondary or miliary spines whatever,
but there are numerous big pedicellariae, 1-2 mm. long. Actinolateral plates
well-covered with rather stout spinelets, about ten to a plate; in alcohol, these
spinelets are conspicuously sacculate but when dry the saccule disappears and

‘ perarmalus = thoroughly armed; in reference to the extreme development of primary spines.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 103

they appear slender and pointed. Pedicellariae also occur on the actinolateral
plates but they are not so large as abactinally. Im alcoholic material, the
rather thick abactinal skin is everywhere elevated into little soft knobs as
many as ten or twelve occurring on a single disk-plate; these completely dis-
appear when the material is dried. Papulae abundant all over dorsal surface,
clear to arm-tips; usually there is only one to an area but on disk and arm-bases
three or four may be found in one area; below the inferomarginals, papulae
are very few and small and none occur below the second series of actinolateral
plates.

Adambulacral plates rather longer than usual in Zoroaster; in the alternate
small plates, length nearly equals breadth. Each small plate has on its
actinal surface in two series, three to five spinelets, the largest being on the
furrow-margin; are all more or less sacculate in alcoholic material; the largest
spinelet is frequently replaced by a large pedicellaria and this is particularly
so in the larger specimen. Each projecting adambulacral plate has on its
actinal surface in two transverse series, four or five spinelets similar to those
on the smaller plates, and in addition, there are three much stouter spines on
the intraambulacral ridge; of these the innermost is smallest and carries at its
tip a huge pedicellaria and two or three small ones; the second spine is thick
and blunt, about 2-2.5 mm. long by .50—.60 mm. thick at base; the outermost
spine is similar but larger, 3-3.5 mm. long, .60-.80 mm. thick. Of other pedi-
cellariae on the adambulacral plates or spines, there are very few or none. Oral
plates short and small; each carries three or four spines, of which the innermost
is shortest, stands on the outer proximal corner of plate and carries at its tip a
huge pedicellaria and one or two smaller ones; the second spine is more slender
and stands nearer the radial line; back of it stands the third and stoutest spine;
back of the latter is the fourth spine when it is present, but it may be wanting
or it may be replaced by a huge pedicellaria. Pedicellariae of varied size may
occur on the sides and at the inner end of the oral plates and in the larger speci-
men they are quite abundant.

Color in alcohol yellow-brown, but this fades out on drying into a dirty
whitish, with papular areas darker and papulae almost black.

Station 4653. West of Peru about 17 miles, 5° 37’S., 81° 24’ W., 536 fms. Bott. temp. 41.3°. Dk. br.
gy. shore m.

Two specimens.

The general appearance of these two specimens is at first glance quite
unlike but when they are carefully compared they are found to be remarkably

104 ASTERIIDAE.

similar. The difference in appearance is due to the more erect position of the
spines in the smaller specimen and to the greater abundance of pedicellariae
in the larger. The latter also has much more tapering arms.

The species is one of the best characterized in the genus for the development
of primary spines on so many abactinal plates, accompanied as it is by the total
absence of small spines, gives a very easily recognized facies. There is little
doubt that perarmatus is more closely allied to fulgens and diomedeae than is

any other one of the eastern Pacific Zoroasters.

Zoroaster magnificus.

Lupwic, 1905. Mem. M. C. Z., 32, p. 159.

There is a fine large Zoroaster in the present collection, R = 270 mm.,
r = 15 mm., which has been labeled by Ludwig as Z. magnificus. It answers
well to the description except in one particular; the spinelets covering the body
are thick and blunt and even when dry are not in the least “‘sabelf6rmig” as
they are described in magnificus. If this difference is anything more than of
degree, it might be of considerable importance but as I have no available speci-
men of magnificus for comparison, I attribute it to individual diversity merely.

Station 4647. Eastern Tropical Pacific, 4° 33’S., 87° 42’ 30” W., 2,005fms. Bott. temp. 35.5°. Lt. gy.
and br. glob. oz.

ASTERIIDAE.

Heliaster cumingii.
Asterias (Heliaster) cumingii Gray, 1840. Ann. Mag. Nat. Hist., 6, p. 180.
Heliaster cumingii DuJARDIN AND Hup®, 1862. Hist. Nat. Zodph. Ech., p. 343.
These two specimens, measuring about 200 mm. across, were taken in
January, 1905, at Chatham Island, Galapagos, a locality from which the species
has long been known. One has thirty-six and the other thirty-eight rays.

Heliaster multiradiatus.

Asterias (Heliaster) multiradiata Gray, 1840. Ann. Mag. Nat. Hist., 6, p. 180.
Heliaster multiradiatus Dusarpin and Hup#, 1862. Hist. Nat. Zoéph. Ech., p. 343.

There are two specimens of this species, taken with the preceding. One
has R = 65-70 mm. and the other has R = 75-80 mm. Each has twenty-six
rays, nearly the maximum number for the species.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 105

.

Stylasterias paschae,! sp. nov.

Plate 4, fig. 3.

Rays nine. R = 100 mm.; r= 10mm.; R=10r. Br. = about 10 mm.
Disk small, flat, covered with a rather heavy skeleton, the plates of which are
much more closely united around the margin than near the center. Rays taper-
ing but little, quite flat, with wide ambulacral grooves. Abactinal skeleton of
ray made up of a carinal series of plates, a dorsolateral series on each side and
the superomarginal series. Actinal skeleton composed only of large, infero-
marginals and adambulacrals; there are no actinolateral plates present. Carinal
plates longer than wide, abruptly wider distally than proximally; the narrow
proximal end overlaps the wide distal end of the next proximal plate; every other
plate is swollen near center or towards proximal end to support a large spine-
bearing tubercle. Dorsolateral plates somewhat smaller than carinals, but
like them in that every other one bears a spine-carrying tubercle; these plates
seem to be placed obliquely, the outer end, which overlaps the upper side of a
superomarginal, being more distal than the inner end. Superomarginal plates
roughly cruciform with rounded ends, much wider than long; the lowest end
overlaps the upper side of an inferomarginal; every other plate has a large
spine-bearing tubercle while each of the alternate plates carries a single large
pedicellaria. It seems probable that in life the spine-bearing carinals and
superomarginals are about opposite each other, while the spine-bearing dorso-
lateral plates alternate with them. This arrangement is not evident however, in
the present, dry specimen. Each of the dorsal spine-bearing plates, both on disk
and on arms, carries a stout bluntly pointed spine, 2-3 mm. long and .50-.70
mm. thick at base. Hach spine is surrounded at or near its base by a wreath of
minute pedicellariae. Besides these forcipulate pedicellariae and the large
forficulate ones on alternate superomarginals, forficulate pedicellariae of diverse
sizes, but none either very large or very small, are scattered irregularly about
all over the dorsal surface. Papular areas rather large, those near the base of
each arm with six or even more papulae. Madreporite small, surrounded by
six large spines, placed near disk-margin.

Inferomarginal plates smaller than superomarginals; each plate bears an
oblique ridge the lower end of which is more distal than the upper; on this ridge
is a series of three spines (sometimes only two) of which the uppermost is a trifle
the longest and least chisel-shaped at tip, while the lowest is a trifle the shortest

1 Pascha = Easter; obviously in reference to the type-locality.

106 BRISINGIDAE.

and most chisel-shaped; the middle spine is a trifle the widest and heaviest;
besides the spines, many inferomarginal plates carry a huge forficiform pedicel-
laria, 1.5 mm. long and 1 mm. wide at base; the uppermost inferomarginal spine
often carries a cluster of forcipiform pedicellariae on its upper side near the
middle or more distally.

Adambulacral plates short and crowded; each carries a pair of subequal,
flattened, narrow, chisel-shaped spines about 2.5 mm. long; many plates carry
also a huge forficiform pedicellaria, 1.5 mm. long by 1 mm. wide, placed on the
- inner distal angle of the plate and hence more or less within the ambulacral
furrow; there are also a few very small forficiform pedicellariae scattered along
the sides of the furrow. Oral plates small, each with two large spines; one at
inner end of plate is about 3 mm. long and over a millimeter wide at its flattened
base; the other is on the surface of the plate near its outer end and is distinctly
longer and narrower. 'Tube-feet distinctly quadriserial, rather slender, not very
crowded.

Color, light brownish yellow (dried) with the spines and pedicellariae nearly
white.

Easter Island; shore. December 21, 1904.

One specimen.

This is one of the most interesting starfishes brought home by the ALBa-
TROSS, not only because of the distinctive combination of characters which it
shows, but because of its locality. It is noteworthy indeed to find on the shores
of so isolated an island a well-marked member of a genus whose nearest species
is thousands of miles away. Yet there is no doubt that this Easter Island star-
fish is a typical Stylasterias, save for the large number of rays; the other mem-
bers of the genus all belong to the northern hemisphere, only one occurring as far
south as the equator. The number of rays, the presence of three inferomarginal
spines and the character and distribution of the pedicellariae serve to distinguish
paschae from any other Stylasterias. Verrill suggested the group only as a sub-
genus of Orthasterias but it seems to be well-circumscribed and is a convenient
group to use, once the disintegration of Asterias is permitted to set in.

BRISINGIDAE.

Fisher’s (1917. Ann. Mag. Nat. Hist., ser. 8, 20, p. 418-431) recent thorough-
going revision of this family, in which he recognizes fifteen genera, makes it
possible as never before to appreciate the diversity it shows. It also reveals

EASTERN TROPICAL PACIFIC ASTEROIDEA. 107

how many notable forms are recent discoveries, and emphasizes the fact that we
are as yet far from realizing the entire content of the family. This idea is still
further emphasized by the present collection, for while there are only eight disks
and some scattered arms from but five stations, no fewer than five species are
represented and four of these are new to science.' The one previously described
species moreover has hitherto been known only from the eastern tropical Atlantic,
where it was taken by the CHALLENGER! Three of the five species were taken
at a single station. These facts all go to show how very incomplete our knowl-
edge of this remarkable deep-sea family still is. Of very few species has sufficient
material been secured to permit real knowledge of the specific characters, and
there is not a single form of which the growth-changes and the limits of indi-
vidual diversity are known. Under such circumstances the addition of new
species based on single and more or less fragmentary specimens is not very
desirable, but on the other hand material so rare and so difficult to secure must
not be ignored. The following notes may be of service in elucidating generic
and specific limits within the family.

Brisingella monacantha,? sp. nov.
Plate 5, fig. 3, 4.

Disk and number of rays unknown. Rays about 200 mm. long, 4 mm.
wide at base, 5.5 mm. wide at middle of genital area and 2.75 mm. wide one
hundred millimeters from base. Genital area begins 10 mm. from proximal
end of ray and extends about 25 mm.; it is covered by delicate naked gray skin
and is crossed by eleven or twelve calcareous ridges (“‘primary costae”’ of Fisher) ;
there are three or four additional costae distal to the swollen area and indications
of four or five more proximal to it; there are two incomplete or secondary costae
on each ray; otherwise there is no calcareous material on dorsal side of rays.
Adambulacral plates about 2 mm. long on proximal half of ray, somewhat
shorter distally; width at proximal end about half length, distinctly less at
middle and slightly more at distal end where there is a marked projection or
peak on the inner corner; at the base of this peak on the actinal surface of plate
but close to the adambulacral margin is a distinet spine-bearing tubercle; on
proximal part of arm, there is a fairly close approximation between costae and

1 Tt is interesting to note that all of the specimens were taken in water more than 2,200 fms. deep
and at a temperature lower than 36° F.

2 monacanthus = having a single thorn or spine, in reference to the armature of the adambulacral
plates.

108 BRISINGIDAE.

adambulacral plates. Inferomarginal plates very small and difficult to detect;
apparently only every alternate plate carries a spine but proximally this alter-
nation is not perfect as there two successive plates may be spine-bearing.
Adambulacral armature consisting of a single spine; on no plate is there any
indication of a furrow-spine or of a point to which it might have been attached.
Both inferomarginal and adambulacral spines are for the most part missing or
when present are broken, but to judge from the fragments distally the infero-
marginals were the larger and both series were encased is thick skin. Infero-
marginal tubercles are placed directly above adambulacral tubercles but only
adjoining every other adambulacral plate. Tube-feet of moderate size arranged
in pairs opposite the distal half of the adambulacral plates; pores about one
millimeter in diameter. Genital glands moderately developed, one on each
side of swollen area.

Station 4651. Peru: west of Aguja Point, 111 miles, 2,222fms. Bott. temp. 35.4°. Fne. stky. gy. m.
Two rays.

Comparison of these rays with Fisher’s figures and description of Brisinga
fragilis (1906. Bull. U. 8. Fish Comm., p. 1115, plate 46, fig. 1, plate 48,
fig. 3, 3a—c), the genotype of Brisingella, has left no doubt in my mind that they
too represent a species of this genus, and one which is apparently unique in its
adambulacral armature. As the uniform absence of a furrow-spine at either
end of the adambulacral plate and the equally uniform occurrence of only a
single actinal spine on the same plates and that aboral, make the recognition
of the species easy, it seems proper to give it a name.

Freyellidea brevispina,! sp. nov.
Plate 5, fig. 1, 2.

Rays 11. Disk 12 mm. across. R = 165 mm. or more. R = about 14d.
Disk circular with nearly vertical sides between the rays, densely beset with
spinelets, .50-.75 mm. long; these spinelets are slender, slightly thickened at
tip where they terminate in two, three, or four short points; occasionally the tip
is blunt; the plates bearing these spinelets are difficult to make out but appar-
ently there is only one spinelet to a plate; pedicellariae of diverse but small size
occur not rarely among the spinelets. Madreporite small but elevated and
prominent on the margin of disk. Rays slender, only a little over 2 mm. wide

\ brevispinus = having short spines, in reference to the unusual oral spines.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 109

at base and with a maximum width, about 12 mm. from base, of only 4 mm.;
genital area very short only about one tenth of ray-length, covered closely by
plates, spinelets, and pedicellariae like those of disk but notably smaller; be-
yond genital area, minute pedicellariae continue for a few joints only on the
dorsal surface; along sides of ray however, they continue more or less abundantly,
and distally they again invade the dorsal surface, so that the tips of the rays
are apparently enclosed in skin densely covered with these very minute pedi-
cellariae.

Adambulacral plates long and narrow, about 2 mm. by .75, so little concave
on the furrow-side that they are almost cylindrical; there is a moderately de-
veloped peak at the inner, distal corner; their armature consists of two spinelets,
one of these is placed on the inner peak of the plate and extends diagonally across
the furrow, while the other is near the center of the plate, or a little distal to it,
on the actinal surface; the furrow-spine is short and thick, not much longer
than width of furrow, and bears a number (5-8) of small pedicellariae; the
actinal spine is very slender, only about 3 mm. long at base of arm but becoming
5 mm. long on distal part of ray; it is very acicular but is clothed in loose skin,
densely covered with very minute pedicellariae and unless this skin is damaged,
the slenderness of the spine is not apparent. Above every other actinal spine
is an inferomarginal spine which at base of arm is only 4 mm. long but reaches
a maximum length of at least 7 mm. distally; the actinal spines overlaid by the
inferomarginals are always noticeably smaller than those which are unaccom-
panied, but the latter are not so large as the inferomarginals; like the actinal
spines, the inferomarginals are clothed in thick, pedicellaria-covered skin.
Tube-feet moderate, in pairs opposite distal part of adambulacrals; pores
about 1 mm. across. Oral plates short, moderately high at distal end with a
keel along midradial line; each plate carries near distal end a long, slender skin
covered spine, about 5 mm. long, distinctly thickened at tip; at distal outer
corner a small, pedicellariae-bearing spinelet like that of the adambulacral plates;
and at inner end, two, or rarely three, short, more or less curved, flattened,
wide spinelets, much wider at tip than at base; some are so wide at tip as to
be almost fan-shaped; inner is much smaller than outer; the latter may be over
a millimeter long and nearly a millimeter wide at tip; these inner oral spines

are not skin-covered and carry no pedicellariae. Color, in aleohol, nearly white.

Station 4740. Eastern Tropical Pacific, 9° 2’ S., 123° 20’ W., 2,422 fms. Bott. temp. 34.2°. Dk. gy.
glob. and rad. oz.

One specimen.

110 BRISINGIDAE.

Examination of the rays shows that there is no evidence of a syzygy at the
base: all of them are still attached to the disk, though broken at,a greater or
less distance from it. The arrangement of marginal, adambulacral, and oral
plates about the mouth seems to be like that of Freyellidea microplaz, the geno-
type. There is a single genital gland on each side of the swollen area at base of
ray. The combination of characters which serves to separate this species from
all those previously known lies in the very long, slender arms, the unusually
short inferomarginal and adambulacral ‘spines, and the extraordinary oral

spinelets.

Freyellidea octoradiata,' sp. nov.

Plate 6, fig. 1, 2.

Rays 8. Disk 16 mm. across. Rays about 185 mm. long or perhaps more
(the tips are missing). R = about 12d. Disk high and slightly tumid, closely
covered with thick overlapping plates, a millimeter across, more or less; in each
interradius, the large interradial plate is conspicuous, occupying the whole side
of the disk in those areas; interradial plates smooth and bare, but all other disk-
plates with several (usually three or four) small, slender spines and rarely one
or two pedicellariae; the latter are nearly always on plates near arm-bases;
spinelets about .50 mm. long, with blunt and often slightly swollen tips. Rays
rather stout, about 5.5 mm. wide at base and 3 mm. wide near middle; genital
area about 35 mm. long and 8 mm. wide, where widest. Basal fourth of ray
more or less covered with spiniferous plates, similar to those of the disk but larger
and carrying more spinelets and pedicellariae; as far out as the genital area
extends, these plates are close together and cover the region completely but
beyond that point they become more and more separated, fewer in number
and smaller in size, until they finally disappear as very minute fragments carry-
ing a single pedicellaria; on the genital area the plates are, as a rule, much wider
than long, and the largest exceed 2 mm. in breadth; near tip, pedicellariae-
covered skin clothes dorsal and lateral parts of ray.

Adambulacral plates rather short and stout, nearly cylindrical; thickness
more than half length; inner, aboral peak present but slender; armature as
usual in the genus; a short spinelet on the peak, extending across furrow and
carrying small pedicellariae; and a large actinal spinelet, the tubercle of which
occupies a large part of distal half of plate; near base of arm, these actinal spine-
lets are very stout with enormously widened flat, dentate tips, as in F. insignis

‘ octoradiatus = having eight rays, in reference to the unusually small number of arms.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 111

but heavier than in that species; beyond genital area, they rapidly assume an
ordinary blunt tip; where longest they are about 5 mm. long and decrease in
length and stoutness distally. Inferomarginal spines at first rather small, not
equalling the actinal adambulacral spines, but distally they gradually come to
exceed them; as usual there are two actinal spines to one inferomarginal, the
latter overlying one of the former. Both actinal and inferomarginal spines are
more or less completely encased in pedicellariae-covered skin. Tube-feet very
large, the pore occupying nearly the whole area bordered by the adambulacral
plate. Oral plates small, with no midradial keel; at distal outer corner is a
small spinelet similar in position and appearance to the adambulacral furrow-
spine, while on the adoral margin are two similar but longer spines which widely
diverge from each other; at the center of the actinal surface of the plate is a long
spine, like the adambulacral actinal spines, with a conspicuously flat dentate
tip; all the oral spines carry numerous pedicellariae. Color, in alcohol, light
buff.

Station 4649. Eastern Tropical Pacific, 5° 17’ S., 85° 19’ 30” W., 2,235fms. Bott. temp. 35.4°. Fne.
stky. gy. m.

Station 4740. Eastern Tropical Pacific, 9° 2’ S., 123° 20’ W., 2,422 fms. Bott. temp. 34.2°. Dk. gy.
glob. and rad. oz. ,

Station 4742. Eastern Tropical Pacific, 0° 3’ 29’ N., 117° 15’ 48” W., 2,320 fms. Bott. temp. 34.3°.
Fne. It. gy. glob. oz.

Three specimens.

Two of these specimens are of nearly equal size but the one from St. 4740 is
-very much younger. The disk is only 7 mm. across; two of the arms are broken
near the disk, the others near their tips or beyond the genital area, which is little
enlarged. None of the adambulacral actinal spines show very much expanded
tips but they are relatively short and in view of the number of rays, I consider
this specimen octoradiata.

The small number of rays, apparently quite constant, the large feet, the
short, thick adambulacral plates, and the relatively short actinal and inferomar-
ginal spines combine to give this species a very characteristic facies. The disk
too is relatively small and the rather stout arms are longer than usual. The
generic characters are well shown, as there is no syzygy at the base of the arm,
the genital tufts are single on each side of the arm and the interradial angle is
as in microplax except for the very much larger interradial plate.

112 BRISINGIDAE.

Freyellidea oligobrachia,' sp. nov.

Plate 6, fig. 3, 4.

Rays 6. Disk 10 mm. across. Rays all broken but certainly more than
90 mm. long and probably in excess of 100. Disk moderately high but flat,
covered with relatively large, thick, irregular plates which more or less overlap;
the largest are about .75 mm. in diameter and carry as many as fifteen spinelets;
spinelets very small with one, two, or three glassy terminal points; around anus
the spinelets are noticeably coarser; there are a few small pedicellariae scattered
among the spinelets. Rays rather stout, about 4 mm. wide at base, and 3 mm.
near middle; genital area not sharply defined, about 20 mm. long and only
4.5 mm. wide, where widest; its covering is very similar to that of the disk,
except that spinelets are fewer and pedicellariae much more numerous; beyond
genital area, the plates disappear quite rapidly.

Adambulacral plates long and slender, the distal end curved inward slightly,
its inner corner prolonged into a long slender peak; armature, of a single spine
about 3 mm. long, which is located on aboral end of plate on actinal surface, and
is normally covered with thick skin, densely clothed with pedicellariae; at base
of ray these spines have flat, expanded, dentate tips but these rapidly give way
to simple points and distally the spines are very acicular; there is no furrow-
spine and no pedicellariae in the furrow. Inferomarginal spines small, acicular,
completely skin covered like the actinal spines, which they seldom equal in
length and never exceed; basally they occur at irregular intervals of 2-4 adam-
bulacral plates but distally they are more regular and seem to accompany every
other actinal spine. Tube-feet rather small, lying against the distal curved end
of adambulacrals. Oral plates small, squarish, little swollen; on actinal surface
at distal end is a long, clavate spine covered with skin and numerous pedicel-
lariae; at adoral outer corner of plate are two or three slender spinelets lying
horizontally and each carrying a few pedicellariae. There is no spinelet at distal
outer corner of plate but there are a few pedicellariae in the furrow at that point.
Color, in alcohol, nearly white.

Station 4656. Eastern Tropical Pacific, 6° 54’ 36” S., 83° 34’ 18” W., 2,222 fms. Bott. temp. 35.2°.
Fne. gn. m., mang. nod.

Station 4742. Eastern Tropical Pacific, 0° 3’ 24” N., 117° 15’ 48” W., 2,320 fms. Bott. temp. 34.3°.
Fne. It. gy. glob. oz.

Three specimens.

* 6Alyos = few + Spaxlw» = arm, in reference to the number of rays, the minimum for the genus.

EASTERN TROPICAL PACIFIC ASTEROIDEA. 113

The specimen described is the largest and is from St. 4742. The one from
St. 4656 is smaller, with disk only 6 mm. across; in all particulars however, it
agrees with the holotype. The third specimen is from St. 4742 and measures
only 4 mm. across the disk; it is surprisingly like the holotype and offers no
features worthy of special comment. The generic characters are well shown
by the holotype, in which the base of each ray contains a well-developed genital
tuft on each side. The junction of the oral plates with the interradial is very
clear in the specimen from St. 4656. The rays of all the specimens are still
attached to the disk, though several are broken off near the base. The presence
of six rays and the absence of a furrow-spine ally this species with the following,
but the general facies is quite different. They evidently form a very distinct

section of the genus.

Freyellidea tuberculata.

Freyella tuberculata SutapEN, 1889. Challenger Ast., p. 638.
Freyellidea tuberculata FisHpr, 1917. Ann. Mag. Nat. Hist., ser. 8, 20, p. 429.

The specimen at hand is of just the same size as the one described by Sladen,
having the disk 12 mm. across and the rays 240 mm. long. It answers to the
description in practically every particular and I have sought in vain for some
character by which the Pacific form might be separated from the Atlantic.
There is then in the discovery of this species in the Pacific by the ALBATROSS
further evidence in support of the view that the true deep-sea fauna is essentially
cosmopolitan.

Station 4742. Eastern Tropical Pacific, 0° 3’ 24” N., 117° 15’ 48” W., 2,320 fms. Bott. temp. 34.3°.
Fne. It. gy. glob. oz.

One specimen and three additional arms.

ae. eee SS
ve a y

EXPLANATION OF THE PLATES.

-

PLATE 1.
- Thoracaster magnus Ludwig. Cotype from Station é
1. Upper surface.
2. Lower surface.
©

.

> =

~~ es. =
a

PLATE 2.

Styracaster monacanthus Ludwig. Holotype from Station 4701. .

Upper surface.
Lower surface.

Styracaster paucispinus Ludwig. Cotype from Station 4658.

Upper surface.
Lower surface.

Albatrossia nuda (Ludwig). Holotype from Station 4647.

i

ae?

©

1.

PLATE 3.

a. >

Hymenaster trias H. L. Clark. Holotype from Station 4672.
Upper surface. ’ .
Lower surface.

.

Litonotaster tumidus H. L. Clark. Paratypes from Station
Upper surface of a long-rayed specimen.
Lower surface of same.

Upper surface of a short-rayed specimen.
Lower surface of same.

PLATE 4.

Hymenaster cremnodesH.L. Clark, Holotype from Station 4658,
1. Seenfromtheside. X 2.

Zoroaster perarmatus H.L.Clark. Holotype from Station 4653.
2. Uppersurface. Nat. size.

Stylasterias paschae H. L. Clark. Holotype from Easter Island.

3. Uppersurface. Nat. size.

cA - th col

wy

nm

i)

PLATE 65.

Freyellidea brevispina H. L. Clark. Holotype from Station

1. Upper surface.
2. Lower surface.

Brisingella monacantha H. L. Clark. Part of ray of paratype fror

3. Lower surface.
4. Side view,

i

$3
&:

C.
4
A
~
:

sd

fo
al

vig
a
oa
-
- a

PLATE 6.

Freyellidea octoradiata H. L. Clark. Holotype from Stati
1. Upper surface.
2. Lower surface.

Freyellidea oligobrachia H. L, Clark. Paratype from Station
3. Upper surface.
4. Lower surface, : x

i/

Memoirs of the Museum of Comparative Zodlogy
AT HARVARD COLLEGE.

Vor. XOGXTX. No. 4:

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION
TROPICAL PACIFIC, IN CHARGE OF ALEXANDER AGASSIZ,

U.

COMMANDING.
XXII.

TO THE
BY THE

S. FISH COMMISSION STEAMER “ ALBATROSS,’ FROM AUGUST,
1899, TO MARCH, 1900, COMMANDER JEFFERSON F. MOSER, U. S. N.,

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

MANDING.
XXXIII.

HOLOTHURIOIDEA.

By HUBERT LYMAN CLARK.

WITH FOUR PLATES.

{Published by Permission of H. M. Smith, U. S. Commissioner of Fish and Fisheries].

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

SEPTEMBER, 1920.

CONTENZES.

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE
TROPICAL PACIFIC, in charge of Alexander Agassiz, by the U. S. Fish Commission
Steamer “Albatross,” from August, 1899, to March, 1900, Commander JEFFERSON F.
Moser, U. S. N., Commanding. XXII.

REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE
EASTERN TROPICAL PACIFIC, in charge of Alexander Agassiz, by the U. S. Fish
Commission Steamer “ Albatross,”’ from October, 1904, to March, 1905, Lieut. Com-
mander L. M. Garrett, U. S. N., Commanding. XXXIII. HototHuriomeEa. By
Hupert Lyman Ciark. With 40 pp. and 4 Plates.

TABLE OF CONTENTS.

Pace
INTRODUCTION : ; : F 5 , é : ; A F : : i ee
SYSTEMATIC ACCOUNT
SYNAPTIDAE
SyNAPTA MACULATA (CHAMiIsso & EYSENHARDT) 5 é 3 ‘ ; , 5 5 124
PROTANKYA ABYSSICOLA THEEL . A F é : : 3 R : 5 ; Al Ze
Curripora Aponocrita H. L. CuarK. Plate 4, fig. 1, 2 . 3 z 3 : : a el 25)
RIGIDA SEMPER . ‘ , z 5 ‘ 3 ‘ F . : =) 9125
Myriorrocuus BATHysBIUS H. L. Cue Plate 4, fig. 3 : A ; ‘ : 126
GIGANTEUs H. L. CuarK. Plate 4, fig. 4 4 : : : : 5 te 7/
MOLPADIIDAE
Motpapia BATHYBIA H. L. CuarK. Plate 3, fig. 2. Plate 4, aS nO 4 Fs .. 29
HOLOTHURIOIDES Cuvier. Plate 3, fig. 1 ‘ : - é F = 1b!)
CERAPLECTANA TRACHYDERMA H. L. Ciark 5 ; 6 : 5 ; 6 é 7 130
CUCUMARIIDAE
CUCUMARIA ABYSSORUM THSEL. Plate 2, fig. 5 ;: 3 ‘ d : 3 , a lol
PSEUDOCUCUMIS AFRICANA (SEMPER) . ; ‘: 3 P | F . : : = Teil
EcHINOCUCUMIS BITENTACULATA (LUDWIG) . 3 5 F : A : : : 52 Alpyl
PELAGOTHURIIDAE
PELAGOTHURIA NATATRIX LUDWIG 3 s : 5 3 S A ‘ 3 A 5 ley
ELPIDIIDAE
PARELPIDIA ANAMESA H. L. Cuark. Plate 3, fig. 3. . 7 5 c ; : az
ScoTOPLANES MURRAYI (THEEL). Plate 3, fig. 6 5 5 ; : ‘i : F else
PERIAMMA TETRAMERUM H. L. Cruarx. Plate 2, fig. 4 . 5 j : : : A ale%!
PENIAGONE BISprcuLaTA H. L. CiarK 5 : = F : 5 5 . : — LB
INTERMEDIA LupwIG ‘ F A 5 : 4 A ‘ : ; » 135
sETOSA LuDWIG : 5 : j ‘ : : 3 : : d = 36
VITREA THEEL . 5 ‘i : . 5 ; 5 ‘ 6 Z : 36
DEIMATIDAE
ONEIROPHANTA MUTABILIS THEEL : 5 5 : a , 4 : : -. 136
ScoropEIMA PARVISPICULATUM H. L. Gasca Plate 4, fig. 7, 8 Z z : : a URY
SETIGERUM LUDWIG 5 5 : 5 i ; ‘ ; 3 ‘ - 138
LAETMOPHASMA FECUNDUM LuDWIG . : ; F 3 4 ‘ ‘ : , - 138
CapHEIRA suLcaTA Lupwia A 3 : ; . 5 ; : : : : BES
PSYCHROPOTIDAE
EvupHRonipes pyscrira H. L. Cuarx. Plate 2, fig. 3 . : ! Z 5 : . 139
veRRUCOSA Lupwic. Plate 1, fig. 2 . F : 5 4 5 < . 140
PsyYCHROPOTES RARIPES Lupwia. Plate 1, fig. 1 i A ‘ ‘ ; : : eet 40
BENTHODYTES GLUTINOSA R. PerRRiER. Plate 2, fig. 1 : : 4 ‘ - ’ a 141
ReEGULARIS H. L. CuarK. Plate 2, fig. 2 . i . 5 i 5 ~~ 4
SANGUINOLENTA THEEL : f : 5 : A : 2 F 3 ES
HOLOTHURIIDAE
MesoTHuriA MEGAPoDA H. L. CuarKk. Plate 4, fig. 9, 10 4 ; ‘ ‘ a “e143
MULTIPES (LupwIG) : . : 3 : : > 243
MULTIPORA H. L. Crark. Plate 4, fig. bie 13 . 3 : p ‘ . 144
SYNALLACTES AENIGMA Lupwia. Plate 3, fig. 4 : 5 ‘ A 4 ; . 144

TRIPLAX H. L. Cuark. Plate 4, fig. 1417 : ; ‘ : : . 145

Pus es
120 CONTENTS. =
PSEUDOSTICHOPUS MOLLIS THEEL 5 a hs

SricHopus CHLORONOTUS BRANDT 5 C 2 é : 2 :
VARIEGATUS SEMPER . : : : . 2 E é 5 . : &
HoLOTHURIA ARENICOLA SEMPER 5 : : 2 2 5 “ 3 Fe i fe
ATRA JAEGER... : é 5 : 5 a og 3 3 5
CINERASCENS (BRANDT) . a ; a = Es : = 3 - mei 4s
nUeiGnas SEMPER. os <0 =. eo
miTaAns LupWIGc. : : 5 é : : é : a
IMPATIENS (FORSKAL) . : 5 2 5 : 3 5 F
LANGUENS SELENKA 5 2 : F 5 i : : ig aes 1
LEUCOSPILOTA (BRANDT) os ete
LUBRICA SELENKA . z a 5 é : ee ea 3 3a Pars
MARENZELLERI LupwiG . 5 3 5 : 2) z fi F
MONOCARIA LESSON 5 A : ® 5 rane . eS eaeatea
PARDALIS SELENKA .—- 5 5 Sac doa Z A : 2 eet
scamea JAEGER WS ke se
ACTINOPYGA LECANORA (JAEGER) Ps s : 2 : i 9, ee
-waunrmans (Quoy & Ganians) . =. 2
PARVULA (SELENKA) : : : ‘ Z : : ae et e 1

Summary oF EcHINODERMS COLLECTED BY THE EXPEDITIONS oF 1891, 1899-1900, AND 1904-
EXPLANATION OF THE PLATES ‘s

nia

TROPICAL PACIFIC HOLOTHURIOIDEA.

INTRODUCTION

Tue number of holothurians collected by the ALBATROssS on her Tropical
Pacific expeditions was not large and hence a single report is preferable. Those
taken in 1899-1900 were originally sent to Professor Mitsukuri at Tokyo and
he had made numerous notes, prepared many slides, and identified many of the
species before his failing health put an end to his work. Later the collection
was received at Cambridge. The collections of 1904-1905 were sent to Pro-
fessor Ludwig at Bonn but his death occurred before he had made any iden-
tifications and the material was forwarded to Cambridge in the spring of 1914.

The earlier collection is a small one, consisting of only fifty-nine specimens,
representing sixteen species, and eleven are common, wide-spread Indo-Pacific
littoral forms. Of the remaining five, two appear to be species hitherto un-
known.

Expedition 1899-1900 — List of Species — (New Species indicated by an *).

Synapta maculata. Holothuria atra.
Pseudocucumis africana. Holothuria difficilis.
Pelagothuria natatrix. Holothuria impatiens.
*Peniagone bispiculata. Holothuria leucospilota.
Peniagone vitrea. Holothuria monocaria.
Euphronides verrucosa. Holothuria pardalis.
*Mesothuria multipora. Holothuria scabra.
Stichopus chloronotus. Actinopyga mauritiana.

The collection of 1904-1905 is a much larger and more interesting one, con-
taining 218 specimens of forty-three species, of which eleven are described as
new and only a dozen are well-known littoral forms. There are also half a
dozen additional specimens, which owing to their condition are quite unidenti-
fiable; they seem to represent three species of Elpidiidae; one is probably refer-
able to Euphronides while the others are apparently Psychropotes.

122 INTRODUCTION.

Expedition 1904-1905 — List of Species — (New Species indicated by an *).

Protankyra abyssicola.
*Chiridota aponocrita.
Chiridota rigida.
*Myriotrochus bathybius.
*Myriotrochus giganteus.
*Molpadia bathybia.
Molpadia holothurioides.
Ceraplectana trachyderma.
Cucumaria abyssorum.

Echinocucumis bitentaculata.

Pelagothuria natatrix.
*Parelpidia anamesa.
Scotoplanes murrayi.
*Periamma tetramerum.
Peniagone intermedia.
Peniagone setosa.
Oneirophanta mutabilis.
*Scotodeima parvispiculatum.
Scotodeima setigerum.
Laetmophasma fecundum.
Capheira suleata

Euphronides verrucosa.
Psychropotes raripes.
Benthodytes glutinosa.

*Benthodytes regularis.
Benthodytes sanguinolenta.

*Mesothuria megapoda.
Mesothuria multipes.
Synallactes aenigma.

*S ynallactes triplax.
Pseudostichopus mollis.
Stichopus variegatus.
Holothuria arenicola.
Holothuria atra.
Holothuria cinerascens.
Holothuria imitans.
Holothuria impatiens.
Holothuria languens.
Holothuria lubrica.
Holothuria marenzelleri.
Actinopyga lecanora
Actinopyga parvula.

*Euphronides dyscrita.

The 1904-1905 collection was always considered by Mr. Agassiz an excep-
tionally important one, an opinion based in part on the remarkably interesting
trawl-hauls at several stations. Thus at station 4647, nine species were obtained,
representing eight different genera, and two of the species are very notable new
forms. At station 4649, five species of five genera were taken, one of the species
being new. At 4651, seven species of seven genera, were secured and at 4656,
five species of five genera. At 4658, eight species of seven genera, with two
new species, were taken, and again at 4672, eight species of eight genera, with
two new species, were brought in. It is not surprising therefore that Mr.
Agassiz looked upon the collection as of great value. That it is not of more
unusual importance, is owing to the facts that even the new forms nearly all
belong to genera previously known from the eastern Pacific, while the ALBA-
TROSS 1891 expedition secured a large proportion of the species occurring in the
deep waters of the region.

The new species described in the present report belong to the four families
Synaptidae, Molpadiidae, Elpidiidae, and Holothuriidae, but the three new
members of this last family are all members of the subfamily Synallactinae. The
identification of deep-water holothurians, especially synallactids and elpidiids,
is rendered difficult by the bad condition in which they reach the surface. It
seems to be very exceptional for them to be taken in uninjured condition. More-

TROPICAL PACIFIC HOLOTHURIOIDEA. 123

over the amount of their muscular contraction, and the particular form assumed,
are subject to extraordinary diversity, as a result of which two very different
specimens may prove to have the same essential structure and the same calea-
reous particles. In many cases the specimens are so distended with fine mud, it
is hopeless to make anything out of the internal structure, and not infrequently
the outer surface of the body-wall is so largely rubbed away, no pedicels are left
and it is difficult to find any calcareous particles. In view of these conditions,
calcareous particles prove exceptionally useful and faith in their genetic signifi-
cance and taxonomic importance is greatly strengthened. It is very doubtful
whether holothurians with essentially different spicules should be placed in
the same genus and it is almost universally true that essential similarity in
spicules indicates close relationship. At present our classification contains
some very large and unnatural groups treated as genera (Cucumaria, Thyone,
and Holothuria for example) which can probably be broken up into a number
of small, natural genera by a proper valuation of their calcareous particles.

Of the new species described, all except the Benthodytes and the Euphron-
ides, are particularly characterized by their spicules. The new Benthodytes
is easily recognized, when well preserved by the body-form and arrangement of
pedicels, and the Euphronides by the size and position of the dorsal appendage,
but whether badly damaged or contracted specimens could be correctly identi-
fied is very doubtful. Of all the new forms, the two remarkable species of Myrio-
trochus are unquestionably the most interesting, as the genus has hitherto been
considered characteristic of the subarctic zone. It is very perplexing to find
the two closely allied species at one and the same station and nowhere else,
for they are unquestionably quite distinct. The new Chiridota is interesting
because it shows a well-marked spicule-character, unusual in this homogeneous
genus. The same is true of the new Molpadia, since that is a genus in which
the calcareous tables often lack any real distinctiveness.

The collections add little to our knowledge of the geographical distribution
of holothurians, except in the notable extension of the range of Myriotrochus,
to which reference has already been made. But it is of some interest to find
Chiridota rigida as far southeast as Easter Island, Benthodytes glutinosa in the
eastern Pacific and Ceraplectana trachyderma so far to the southward of the
type-locality, the only place whence it was hitherto known.

The colored figures (Plates 1-3) were prepared by Mr. Agassiz and Mr.
Westergren during the voyage of 1904-1905, but unfortunately the specimens
from which they were made were not preserved separately or otherwise ade-

124 SYNAPTIDAE.

quately indicated, and hence in only a few cases has it been possible to deter-
mine from what specimen the colored figure was drawn. Each of the drawings,
however, has the date and the number of the station at which the specimen was
taken and it has therefore been possible in most cases by a process of elimina-
tion to find the probable originals. But doubts remain, and in two instances
there seem to be no originals preserved. One of these figures having little that
is distinctive is accordingly omitted from the published plates but the other
is of such an unusual color (Plate 3, fig. 5), its publication seems desirable,

especially since there is little doubt as to the genus.

SYSTEMATIC ACCOUNT.

SYNAPTIDAE.
Synapta maculata.

Holothuria maculata Cuamaisso & Eysennarpt, 1821. De anim. Kotzebue obs., p. 352.
Synapta maculata JAcER, 1833. De Holothuriis, p. 15.

This species was met with by the ALBaTRoss twice on her earlier voyage.
At Papeete, September 28, 1899, a good example of the typical form was secured
and at Makemo, in the Paumotus, October 21 of the same year, two hand-
somely marked specimens of the variety agassizi (S. agassizw Selenka) were
taken. These specimens are very conspicuously striped, five nearly white
bands alternating with five more or less mottled brown ones of about the same
width. Sufficient knowledge of this variety in life, and of the species as well,
is as yet lacking, so that the true relation between them is unknown.

Protankyra abyssicola.

Synapta abyssicola THéEL, 1886. CHALLENGER Hol., pt. 2, p. 14.
Protankyra abyssicola OsTERGREN, 1898. Ofv. K. Vet. Akad. Forh., 55, no. 2, p. 117.

At two stations, this species was met with in 1904. Many of the specimens
are of such size as to show that the species reaches a length of 150 mm. or more
in life, with a corresponding diameter of at least 10 mm. In most of the speci-
mens, the color is yellowish without red pigment but one is somewhat reddish.
All have the full-sized anchors with distinct teeth on the arms, so that these
specimens are certainly not P. pacifica. The appearance of the anchors, the
developmental stages of which have perfectly smooth arms, leads one to question
whether pacifica is really a valid form.

Station 4651. West of Peru, 5° 41’ 42” S., 82° 59’ 42” W., 2,222 fms. Bott. temp. 35.4°. Stky. fne.
gy. s., trace of shore-mud.

TROPICAL PACIFIC HOLOTHURIOIDEA. 125

Station 4666. Eastern Tropical Pacific, 11° 55’ 30’’ S., 84° 20’ 18” W., 2,600 fms. Bott. temp. 34.9°.
Lt. gy. oz.

Sixteen specimens.

Chiridota aponocrita,' sp. nov.
Plate 4, fig. 1, 2.

Length in life, apparently about 75 mm.; the two fragments of the holo-
type measure in their preserved condition, 20 X 5 mm. and 15 X 4 mm. but
these seem to constitute only about half the animal. Color (preserved), creamy
white. The anterior piece bears twelve tentacles, each with seven digits on a
side; tentacles 2-3 mm. long; terminal digits a full millimeter. Calcareous
ring narrow, with no conspicuous projections on either margin; tentacle-bases
relatively large, nearly concealing calcareous ring.

Calecareous particles numerous and characteristic. In tentacles, rods few,
40-60 » long (Plate 4, fig. 1) very slightly branched at one or both ends, very
little curved. Wheel-papillae numerous in all interambulacra anteriorly but
few and scattered in ventral interambulacra at middle of body and perhaps
posteriorly too; the absence of an indubitable posterior end prevents a positive
decision. Wheels numerous in each papilla, and of diverse sizes, ranging from
55 to 110 » in diameter. Body-wall everywhere, even in skin overlying wheel-
papillae, crowded with minute curved rods or doughnut-shaped particles (Plate 4,
fig. 2) only 12-20 u long. No calcareous particles in longitudinal muscles.

Panama: Perico Island.

Three fragmentary specimens.

This Chiridota, although superficially not unlike several of the smaller
members of the genus, is easily distinguished by the uniform coat of miliary
particles in the outer layer of the body-wall. These are so numerous and small
and have such a characteristic form, that aponocrita is one of the most easily
recognized members of the genus. It is apparently a littoral species and no
doubt occurs elsewhere at Panama, than at Perico Island.

Chiridota rigida.
Semper, 1868. Holothurien, p. 18.
There are two headless specimens in the 1904-1905 collection, measuring
25-30 mm. long by 4-5 mm. in diameter, which seem to be this species, though
of course they are not certainly identifiable. They are of special interest because

1 @rovos = without trouble + xplros = picked out, in reference to the ease with which it may be

distinguished from allied forms.

126 SYNAPTIDAE.

they were taken on the shores of Easter Island, December 20, 1904. The wheels
Croke 45-65 » in diameter and the curved rods, which are very sparsely
scattered and not very variable, are but 27-36 u in length. The small species
of Chiridota need a careful revision based on the size, character, and distribution
of the calcareous particles and when this is made the Easter Island form may be
entitled to rank as a separate species, as the wheels seem to be much smaller

than in typical rigida.

Myriotrochus bathybius,' sp. nov.
Plate 4, fig. 3.

Length of preserved specimen, 33 mm.; diameter, 8 mm. Oral disk, 8 mm.
across, with scattered yellow-brown papillae, most numerous near mouth, each
about one fourth of a millimeter high. Tentacles twelve, each with three minute
digitations on each side. Color, gray; outside of circle of tentacles there are
seven dark spots lying between tentacle-bases. Calcareous ring stout, with
distinct projecting points on the anterior margin of both radial and interradial
pieces; the posterior margins are, on the contrary, almost straight. Stone-canal
single, short, compact, free. Polian vessel, single, long. Genital glands well
developed on each side.

Caleareous particles consist of wheels alone, no deposits of any kind being
found in the tentacles or oral disk. Wheels (Plate 4, fig. 3) very few and widely
scattered; it may be that their scarcity is due to the abrasion of the epidermis
during the long and rough journey to the surface in the trawl. Of the four seen,
one had twelve, two had thirteen and one had fourteen spokes. Only two of
these wheels were sufficiently uninjured to make the count of the teeth on the
inner margin accurate; in a wheel with twelve spokes there were thirty-seven
teeth and in one with thirteen spokes there were thirty-eight teeth. Evidently
then the wheels in this species have typically thirteen spokes with the teeth
three times as numerous. The most important feature of the wheels, however,
is the hub which, as will be seen from the figure, is relatively large and has a
circle of small oval perforations around the center. A few developmental stages
of the wheels were found which explain this curious arrangement. As is the case
with all wheels in the Synaptidae, the first beginning is a minute circular disk.
Projections soon arise all around the margin and these lengthen into the spokes,
which ultimately expand bilaterally at the tip, these expansions fusing with each
other and forming the rim of the wheel. In the present species when the length

* BabiBios = deep-living, in reference to the great depth at which it occurs.

TROPICAL PACIFIC HOLOTHURIOIDEA. 127

of the spokes is somewhat greater than the diameter of the original hub, a swelling
appears near the middle of each spoke and as these swellings widen they come
in contact and fuse with each other, leaving the circle of small oval holes, which
apparently never fill up. The number of these holes thus corresponds to the
number of spokes. The three wheels which were sufficiently complete to permit
measurement were 240, 300 and 340 u» in diameter, with marginal teeth about.

Station 4647. Hastern Tropical Pacific, 4° 33’ S., 87° 42’ 30’ W., 2,005 fms. Bott. temp. 35.5°. Lt. gy.

and br. glob. oz.

One specimen.

Although the superficial resemblance of this specimen is very close to that
of the smaller of the two specimens of M. giganteus, the wheels are so different,
it is impossible to consider it simply an aberrant example of the same species.

The question of the relationships of bathybius is discussed under giganteus.

Mpyriotrochus giganteus,! sp. nov.
Plate 4, fig. 4.

Length 53 mm.; diameter 20 mm.; oral disk 12 mm. across. Form dis-
tinctly like Molpadia but for the lack of any caudal appendage. Smaller speci-
men, very much contracted and deformed, 35 mm. long, 9 mm. in diameter
anteriorly but only 4 mm. at middle and posteriorly, and with oral disk 7 mm.
across. Tentacles twelve, with 5-7 short but distinct digits on each side.
Color, of smaller specimen gray; of holotype, light brown on a gray foundation,
with area around anus and another area just back of and including tentacles
on dorsal side, deep purple. Calcareous ring stout, with the radial pieces having
rounded posterior, and broad blunt anterior, projections, and the interradial
pieces similar except that the anterior projection is pointed. No stone-canal
was found. Polian vessel single, small. Genital glands well developed on each
side.

Caleareous particles are wheels alone, no deposits of any kind being found
in the tentacles or oral disk. Wheels (Plate 4, fig. 4) fairly numerous but widely
scattered; somewhat more numerous dorsally near the two ends of the animal
than elsewhere, apparently, but this may be result of greater abrasion near middle
of body. Of twenty-seven wheels observed sufficiently perfect to permit count-
ing spokes, two had ten, nine had eleven, eight had twelve, seven had thirteen,
and one had fourteen spokes, an average of not quite twelve spokes per wheel.

1 yeyavréwos = like a giant, in reference to the exceptionally large size for a Myriotrochus.

128 SYNAPTIDAE.

Only twenty-three wheels were suitable for counting the marginal teeth and in
ae iene great diversity, the number ranging from twenty-one to thirty;
the average number per wheel is a trifle more than twenty-four, or just about
twice the number of spokes; the largest relative number is twenty-seven teeth
for ten spokes and the smallest is twenty-two teeth for thirteen spokes. Hub
of wheel small and solid, its diameter .20-.25 of wheel diameter. Wheels range
from 190 to 315 » across with the marginal teeth 30-50 u long.

Station 4647. Eastern Tropical Pacific, 4° 33’ S., 87° 42’ 30” W., 2,005fms. Bott. temp. 35.5°. Lt. gy.
and br. glob. oz.

Two specimens.

The oceurrence of two species of Myriotrochus south of the equator and
at a depth of over two thousand fathoms is one of the most extraordinary 206-
logical discoveries made by the ALBATROsS during her 1904-1905 cruise. The
genus has not hitherto been known south of Norway, Newfoundland, Alaska,
and northern Japan, nor at a depth of more than a few hundred fathoms. The
species taken at station 4647 are very different in general appearance from any
of the known forms, but giganteus is much like the common subarctic species
rinkii in the character of its wheels. The wheels of giganteus average a trifle
larger than in rinkii but the difference is insignificant. The spokes, however,
are noticeably fewer (10-14, average almost twelve, as against 12-22, average
seventeen) and much wider, while the hubs are larger (.20—.25 wheel-diameter
as against about .16). The marginal teeth are relatively more numerous in
giganteus, where they average almost exactly double the number of spokes.
The wheels in bathybius are conspicuously different from those of any other
member of the genus. Both the tropical species seem to be much larger and
stouter than rinkii, the largest of the previously known species, although there
is not great difference in length, since Ostergren reports specimens of rinkit
up to 70 mm. long in life. The superficial resemblance of giganteus in form and
color to a Molpadia is very striking and only the examination of the calcareous
particles proves how misleading the resemblance is.

It was hard to convince myself that the holotype of bathybius was not
merely an aberrant individual of giganteus, but the wheels are too markedly and
consistently different to support such an idea. Moreover the differences in the
digitation of the tentacles and in the calcareous ring cannot be ignored and no
other conclusion seems possible than that these two closely-allied species live
together on the ooze in the great depths of the eastern Pacific. It is an
environment peculiarly suited to holothurians, as is well shown by the fact that
nine different species were taken in the single haul of the trawl at station 4647.

TROPICAL PACIFIC HOLOTHURIOIDEA. 129

MOo.LPabDrpDaek.
Molpadia bathybia,! sp. nov.
Plate 3, fig. 2; Plate 4, fig. 5, 6.

Length 50 mm., of which about 5 mm. is caudal appendage; diameter
about 17 mm. Tentacles contracted out of sight and whole oral disk more or
less shrunken. Body-wall, very thin. Color, gray. No phosphatic deposits.
Caleareous particles, tables only but these very abundant though not crowded.
Tables not perfectly symmetrical but not notably asymmetrical, and the disks
never have projecting rods, nor do they tend to narrow down in the posterior
end into supporting rods; disks (Plate 4, fig. 5) 200-300 » across with three
primary holes, three secondary holes, often nearly as big, and not uncommonly
additional marginal holes, so that there may be twenty or even more perfora-
tions; spire (Plate 4, fig. 6) made up at base of three rods which quickly fuse
into a smooth straight rod with blunt tip, 200-250 u high.

Station 4670. Peru: west of Palominos Light House, 105 miles. 3,209fms. Bott. temp. 35.4°. Fne.

dk. br. m.
Station 4672. Peru: southwest of Palominos Light House, 88 miles. 2,845 fms. Bott. temp. 35.2°.

Fne. dk. br. infus. m.

Two specimens.

The holotype is from station 4672. The other specimen (Plate 3, fig. 2) is
slightly smaller but has the same proportions, with the tentacles somewhat less
contracted and apparently fifteen in number. There are no phosphatic bodies
and the calcareous particles are as in the holotype. This species is nearly allied
to M. arctica but the tables are markedly different. In the absence of phos-
phatic bodies and supporting rods and the total lack of anchors and plates,
bathybia is easily distinguished from all the species hitherto known from the
eastern tropical Pacific.

Molpadia holothurioides.
Plate 3, fig. 1.

Cuvier, 1817. Reg. Anim., 4, p. 24.
Molpadia musculus Risso, 1826. Hist. Nat. Europe, 5, p. 293.

In Apodous Holothurians (Washington, 19087), I accepted holothurioides
as the type of the genus Molpadia but did not accept it as a valid specific name
within the genus, placing it instead as a questionable synonym under M. mus-

' Ba6bBvos = deep-living, in reference to the unusual depth of its habitat.
? Although dated 1907, this book was not issued until January, 1908.

130 MOLPADIIDAE.

culus. Such a course now seems illogical and the acceptance of Cuvier’s specific
name is the most satisfactory solution of the difficulty. There is little doubt
that Cuvier and Risso were dealing with the same species and since Ludwig
has clearly shown what the species is, described as musculus by Risso, that
species ought to bear Cuvi jer’s name.

The species has a wide distribution and probably the name in its present
sense really covers several valid species, but the specimens in the present col-
lection throw no light on the matter. They range from 30 to 115 mm. in length.
The smallest have very insignificant caudal appendages, relatively few phos-
phatic bodies, and many anchors; several are evidently Ankyroderma spinosum
Ludwig. The largest specimens are quite red from the crowded phosphatic
deposits, and their caudal appendages are relatively long.

The two colored figures given, obviously do not represent a single species.
There is little reason to doubt that Plate 3, fig. 1 represents an adult holothu-
rioides, though the color is more roseate than would be expected and the absence
of a caudal appendage is notable. But Plate 3, fig. 5, while almost certainly
a Molpadia can hardly be holothurioides. The figure is published in order to
record the occurrence in the Eastern Pacific of a holothurian, having this most
unusual green color. The drawing is based on a specimen recorded from sta-
tion 4630, but there is no molpadiid in the collection now from that station;
at 4631, however, M. holothurioides was taken.

Station 4631. Panama: off Mariato Point, 72 miles. 774 fms. Bott. temp. 38°. Gn. s.
Station 4651. Peru: west of Aguja Point, 111 miles. 2,222 fms. Bott. temp. 35.4°. Fne. stky. gy. m.

Station 4672. Peru: southwest of Palominos Light House, 88 miles. 2,845 fms. Bott. temp. 35.2°.
Fne. dk. br. infus. m.

Twenty specimens.

Ceraplectana trachyderma.
H. L. Crarx, 1908. Apod. Hol., p. 39.

The rediscovery, off the coast of Peru, in very deep water, of this remark-
able holothurian hitherto known only from the type-locality in the vicinity of
the Aleutian Islands, is one of the interesting results of the 1904-1905 expedi-
tion. The specimens are in very good condition, except that one has all but one
of the curious horny tentacles missing; apparently they have been torn off.
The larger specimen is 52 mm. long and 17 mm. in diameter, with a caudal
appendage about 9 mm. in length. The smaller specimen is about four fifths
as large. The color is gray finely speckled with brownish red, but the oral disk

TROPICAL PACIFIC HOLOTHURIOIDEA. 131

is nearly white with the tentacles bright brown in sharp contrast. In no impor-
tant particular do these specimens differ from those originally described.

Station 4672. Peru: southwest of Palominos Light House, 88 miles. 2,845 fms. Bott. temp. 35.2°.
Fne. dk. br. infus. m.

Two specimens.

CUCUMARIIDAE.

Cucumaria abyssorum.
Plate 2, fig. 5.
THEEL, 1886. CHALLENGER Hol., pt. 2, p. 66.

The specimens range from 50 to 75 mm. in length and call for little comment.
Examination of the body-wall seems to indicate that the calcareous particles
decrease in number with age. At any rate, the largest specimens lack spicules
more or less completely.

Station 4647. Eastern Tropical Pacific, 4° 33’ S., 87° 42’ 30’ W., 2,005 fms. Bott. temp. 35.5°. Lt. gy.
and br. glob. oz.

Station 4649. Eastern Tropical Pacific, 5° 17’S., 85° 19’ 30” W., 2,235 fms. Bott. temp. 35.4°. Fne.
stky. gn. m.

Station 4651. Peru: west of Aguja Point, 111 miles. 2,222fms. Bott. temp. 35.4°. Fne. stky. gy. m.

Station 4656. Eastern Tropical Pacific, 6° 54’ 36” S., 83° 34’ 18” W., 2,222 fms. Bott. temp. 35.2°.
Fne. gn. m., mang. nod.

Thirteen specimens.

Pseudocucumis africana.

Cucumaria africana SEMPER, 1868. Holothurien, p. 53.
Pseudocucumis africana Lupwic, 1888. Zool. Jahrb. Syst., 3, p. 815.

On February 8, 1900, six specimens of this very well-marked species were
taken at Kusaie in the Caroline Islands, on a reef. This seems to be the most
easterly record for the species, which is now known from Japan on the north
to Torres Strait on the south and from Portuguese Hast Africa eastward to
Kusaie.

Echinocucumis bitentaculata.

Sphaerothuria bitentaculata Lupwia, 1893. Bull. M. C. Z., 24, p. 112.

It is difficult to believe that there is any generic distinction between Echino-
cucumis typica Sars and Ludwig’s Sphaerothuria bitentaculata. In the con-
tracted condition in which they are ordinarily taken, it is very difficult, if not
impossible, to determine the number and relative sizes of the tentacles, and it
is doubtful whether the supposed differences are real and constant. R. Perrier
considers Ludwig’s genus a synonym of E. Perrier’s Ypsilothuria and of this

132 ELPIDIIDAE.

there can be little doubt, but I believe Perrier’s genus synonymous with Sars’s.
Whether there is more than one species in the genus is not yet satisfactorily
determined for the diversity of form even in specimens from the same spot is
very great, and it is yet to be shown how much of this is natural and how much
is artificial, i. e. the result of contraction during preservation. The specimen
in the present collection is 13 mm. long and 10 mm. high; the anal tube is 2-3
mm. long but the oral end is strongly contracted and no tentacles are visible.

Station 4631. Panama: off Mariato Point, 72 miles. 774 fms. Bott. temp. 38°. Gn. s.

One specimen.

PELAGOTHURIIDAE.

Pelagothuria natatrix.
Lupwie, 1893. Bull. M. C. Z., 24, p. 111. ’

This remarkable pelagic holothurian must be quite common in the eastern
tropical Pacific for it is well represented in both of the ALBaTRoss collections.
But all of the specimens are in poor condition and offer nothing additional to
Ludwig’s very full description. They are all of about the same size, appar-
ently adult. The following list of stations is interesting as throwing much
light on the distribution.

Station 16.1. Eastern Tropical Pacific (660 miles northeast of the Marquesas), 2° 38’ N., 137° 22’ W.
2,440 fms.

Station 17. Eastern Tropical Pacific, 0° 50’ N., 137° 54’ W., 2,463 fms.

Station 4641. Galapagos: Hood Island, 12 miles southeast of Ripple Point, 633 fms.

Station 4645. Galapagos: south of Chatham Island, 1,955 fms.

Station 4646. Eastern Tropical Pacific, 4° 1’ 36” S., 89° 16’ 18’ W., 2,058 fms.

Station 4715. Galapagos: southwest of Hood Island; tow at 300 fms.

Station 4716. Galapagos: 55 miles southwest of Hood Island; surface tow.

Station 4717. Eastern Tropical Pacific, 5° 10’ S., 98° 56’ W.; tow at 300 fms.

Station 4721. Eastern Tropical Pacific, 8° 7’ 30’ S., 104° 10’ 30” W.; tow at 300 fms. and up to surface.
Station 4742. Eastern Tropical Pacific, 0° 3’ 24” N., 117° 15’ 48” W.; tow at 300 fms.

Thirty-three specimens.

ELPIDIIDAE.
Parelpidia anamesa,? sp. nov.
Plate 3, fig. 3.
Length 85 mm.; diameter, 15mm. Color, light yellow-brown. Body-wall
very thin and soft. Tentacles ten. The specimen is in such poor condition
and so filled with mud, none of the details of the internal organization could

* Bottom temperature and character of bottom omitted, since the species is pelagic.

* évaueoos = intermediate, in reference to the fact that the species seems to connect Parelpidia
and Peniagone.

TROPICAL PACIFIC HOLOTHURIOIDEA. 133

be made out; not even a calcareous ring was detected. Posterior end of body,
flattened. Pedicels present around posterior end, but their number, size, and
relative positions could not be determined. Calcareous particles character-
istic; in skin of dorsal surface are quadriradiate spicules, each of the four, only
very slightly thorny branches curved inward rather strongly, while from their
common center arises an outwardly directed nearly smooth spine; the curved
rods are 350-550 u long and the projecting spine 300-400 u; in the ventral
skin, the spicules are smaller with less curved rods and two to four low, rough,
projecting spines or knobs, much as in Peniagone intermedia.

Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 35’ 36” W., 2,370 fms. Bott. temp. 35.3°. Fne.

gn. m., mang. nod.

One specimen.

It is by no means sure that this species is properly referred to Parelpidia
rather than to Peniagone but the elongated form and the apparent absence of
any dorsal appendage seem to justify the position given. The spicules of the
dorsal surface are the really characteristic feature and will serve to distinguish
even more badly preserved specimens than the holotype (Plate 3, fig. 3). Judg-
ing from the colored drawing, made from life, there are only three pedicels on
each side of the body and these are widely separated. There seem to be none
around the flattened posterior end.

Scotoplanes murrayi.
Plate 3, fig. 6.

Elpidia murrayi THEEL, 1879. Bih. K. Sven. Vet. Akad. Handl., 5, no. 19, p. 16.
Scoloplanes murrayi THEEL, 1881. CHALLENGER, Hol., pt. 1, p. 34.

The ALBATROSS specimens are all much larger than the holotype of murrayi,
ranging from 55 to 85 mm., but there seems no good reason for considering them
specifically distinct. The calcareous particles are actually larger than in
Théel’s specimen but relatively they are about the same. The rods are 1-1.25
mm. long and correspondingly stout; they are abundant; the C-shaped bodies
are also very plentiful and relatively large. The skin is very thin and owing
to the abundance of the spicules is quite brittle. The left-hand papilla in one
specimen (Station 4672) is double. In the same specimen, there are only five
papillae in one lateral series, though there are siz in the other. This specimen
is further remarkable for having contained a parasitic worm, apparently an Ich-
thyonema.

134 ELPIDIIDAE.

Station 4651. Peru: west of Aguja Point, 111 miles. 2,222 fms. Bott. temp. 35.4°. Fne. stky. gy. m.
Station 4672. Peru: southwest of Palominos Light House, 88 miles. 2,845 fms. Bott. temp. 35.2

Fne. dk. br. infus. m.
Four specimens.

Periamma tetramerum,! sp. nov.

Plate 2, fig. 4.

Length, 50 mm.; diameter, 15 mm. Body-wall very thin and delicate.
Color, pale yellowish brown and grayish; the gray areas appear to be where the
brown is rubbed off. Tentacles ten. Pedicels, eight on each side, the most
anterior largest (2 mm. long or more), situated anterior to middle of body;
the posterior four smallest and more or less united together. About 12 mm.
back of anterior end is a transverse crest, 8-9 mm. wide and 4 mm. high, more
or less lobed, but not markedly so; this crest is apparently made up by the
fusion of two pairs of processes, 7. e. four projecting papillae, and back of it,
there is on each side a similar papilla 1.5 mm. high. General appearance much
like a small Scotoplanes robusta. Internal anatomy completely indeterminable
owing to the whole interior being densely packed with mud.

Caleareous particles very characteristic. In deeper layer of skin are
numerous C-shaped (sometimes S-shaped) bodies, 100 1 long. External to these
is a layer of very diversified thorny spicules, generally tetramerous; each forms
a more or less perfect cross with two opposite arms shorter than the other two;
rarely the spicules are trimerous or pentamerous; each arm of a spicule is usu-
ally about 100» long but often they are less. Here and there among these
crosses are much stouter, thorny rods, 200-300 » long; these often have a
short branch, at a right angle, on one side, near the middle. Fe

Station 4670. Peru: west of Palominos Light House, 105 miles; 3,209 fms. Bott. temp. 35.4°. Fne.
dk. br. m. ;

Six specimens.

These specimens seem to have suffered considerable damage in the ascent
of the trawl, for in the largest ones the outer spicule layer is nearly all rubbed
off leaving only the C-shaped particles. The dorsal crest is more or less dam-
aged but its form and size are fairly recognizable. The number, size, and
arrangement of the pedicels is also distinguishable in most of the specimens.
The spicules are very characteristic and there will be no difficulty in recogniz-

ing examples of the species where enough of the epidermis is intact to permit
the existence of the crosses to be determined.

; , Lae : See
rerpauepos = having four parts, in reference to the characteristic spicules.

TROPICAL PACIFIC HOLOTHURIOIDEA. 135

Peniagone bispiculata,! sp. nov.

Length about 45 mm.; width, back of middle, about 30 mm. Body oval,
narrower in front, very flat in the preserved specimens but probably less so in
life. Tentacles ten, relatively large. Oral surface with 10-12 very large pedi-
cels surrounding it, beginning near mouth on each side; even in their con-
tracted condition these pedicels are several millimeters long and 2 mm. thick
at base. Dorsal crest thin, rather low, rounded, about 10 mm. wide by 5 mm.
high, placed close to anterior end of body. On right side, 12 mm. back of
crest, is a papilla 6 mm. long by 2 mm. thick, pressed down flat against body;
no corresponding papilla can be detected on the left side but it may have been
broken off, and as the whole body-surface is very much wrinkled and folded,
its point of attachment is no longer to be found. Color, gray (holotype) or
pinkish (paratypes).

Caleareous particles not very distinctive except by size; they resemble
those of P. intermedia but are more slender and have more pointed tips to the
four inwardly curved arms; these arms are 100-120 u long; here and there among
these small and very numerous spicules are scattered abruptly larger ones with
arms 150-170 u long.

Station 17. Eastern Tropical Pacific, 0° 50’ N., 137° 54’ W., 2,463 fms. Bott. temp.? Lt. yel.-gy.
glob. oz.

Three specimens.

While this new Peniagone resembles vitrea and intermedia in certain par-
ticulars, the arrangement of the large pedicels and the form of the body are very
different from what is found in either of those species. The size of the spicules
and particularly the existence of two very different sizes are also distinctive
points. It is at least worthy of note that while the holotype is fairly well pre-
served the paratypes are in very bad condition, each of them being split open
down the back for the entire length. The appearance suggests that with the
release from the bottom-pressure these specimens exploded leaving only the
empty skin, which had proved weakest along the middorsal line.

Peniagone intermedia.
Lupwia, 1893. Bull. M. C. Z., 24, p. 109.

The specimens referred to this species are in such poor condition, that
their identification is far from certain. They are supposed to belong to inter-

1 bispiculata = having two kinds of spicules, in reference to the two distinct sizes in the calcareous
particles.

136 DEIMATIDAE.

media because of a fairly close similarity in calcareous particles but whether
the dorsal appendage and the pedicels are also similar, it is out of the question
to determine. They certainly add nothing to our knowledge of the species.

Station 4647. Eastern Tropical Pacific, 4° 33’ S., 87° 42’ 30” W., 2,005 fms. Bott. temp. 35.5°. Lt. gy.

and br. glob. oz.
Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 35’ 36’ W., 2,370 fms. Bott. temp. 35.3°.

Fne. gn. m., mang. nod.
Station 4672. Peru: southwest of Palominos Light House, 88 miles. 2,845 fms. Bott. temp. 35.2°.

Fne. dk. br. infns. m.

Ten specimens.
Peniagone setosa.

Peniagone vitrea var. setosa Lupwic, 1893. Bull. M. C. Z. 24, p. 109.

Comparison of the present specimen with a cotype of Ludwig’s variety
has satisfied me that the two are identical and that both are perfectly distinct
from vitrea Théel. I therefore raise the variety to full specific rank. It is
easily recognized by the abundance and large size of, the spicules, the curved
arms of which are 300-530 y in length, with the outwardly directed spines, 300-
470 uw. The ALBATROSS specimen is lighter and less gray than the cotype and
the crest is much less evident. The length is rather more than 50 mm.

Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 35’ 36” W., 2,370 fms. Bott. temp. 35.3°. Fne.
gn. m., mang. nod.

One specimen.
Peniagone vitrea.

Tweet, 1881. CHALLENGER Hol., pt. 1, p. 50.

Although the specimen at hand is badly rubbed and lacks its tentacles, and
although the integument is not at all glassy or “hard, brittle and rough,” I
feel little doubt about the identity, for the shape of the body, the arrangement
of the pedicels and the calcareous particles agree well with Théel’s description.
The color is yellowish white and the body-wall is quite opaque. The body
posterior to crest is 50 mm. long, anterior to crest is 30 mm. and its width is
25 mm. The crest is 25 mm. high and while its margin is irregular there are
no definite four projections visible. There is a note with the specimen indicating
that the color in life was “‘ pink.”

Station 17. Eastern Tropical Pacific, 0° 50’ N., 137° 54’ W., 2,463 fms. Bott. temp.? Lt. yel.-gy.
glob. oz.

DEIMATIDAR.

Oneirophanta mutabilis.
Tuéet, 1879. Bih. K. Sven. Vet. Akad. Handl., 6, no. 19, p. 6.

The present series confirms Théel’s statements concerning the diversity
shown by this species. I doubt very much the validity of the species which

TROPICAL PACIFIC HOLOTHURIOIDEA. 137

have been proposed in Oneirophanta during the period since the CHALLENGER
Report was published. They seem to me to come well within the range of
diversity shown by mutabilis. If all are valid, the specimen in the present col-
lection from Station 4732 may well be made the type of a new species. It
is about 80 mm. long and the pedicels and processes are so few and small they
might easily be overlooked; the body-wall is like thin glass and the body is
full of fine light-colored sand. The other specimens range from 45 to 200 mm.
in length and are for the most part glassy and nearly white but one of the larg-
est specimens is quite brown. The extent of digitation shown by the tentacles
and the number of midventral pedicels are characters of very great diversity.
The number and size of the lateral pedicels also show a great range as Théel
pointed out; in one specimen 150 mm. long, the pedicels are 20 mm. long by
6 mm. in diameter while the marginal papillae are 45 mm. long and 8 mm.
thick at the base. The calcareous plates are very characteristic and while
they show considerable diversity, the specific features are not obscured.
Station 4647. Eastern Tropical Pacific, 4° 33’S., 87° 42’ 30” W., 2,005 fms. Bott. temp. 35.5°. Lt. gy.
and br. glob. oz.
Station 4649. Eastern Tropical Pacific, 5° 17’ S., 85° 19’ 30” W., 2,235 fms. Bott. temp. 35.4°. Fne.
stky. gr. m.
Station 4651. West of Peru, 5° 41’ 42’ S., 82° 59’ 42”” W., 2,222 fms. Bott. temp. 35.4°. Stky. fne.
gy. s., trace of shore-mud.
Station 4656. Eastern Tropical Pacific, 6° 54’ 36” S., 83° 34’ 18’”” W., 2,222 fms. Bott. temp. 35.2°.
Fne. gn. m., mang. nod.
Station 4658. Eastern Tropical Pacific, 8° 30’S., 85° 36’ W., 2,370 fms. Bott. temp. 35.3°. Fne. gn.m.,
mang. nod.

Station 4732. Eastern Tropical Pacific, 16° 32’ 30’ S., 119° 59’ W., 2,012 fms. Bott. temp. 34.8°.
’ Lt. gy. glob. oz.

Sixteen specimens.

Scotodeima parvispiculatum,! sp. nov.

Plate 4, fig. 7, 8.

Length, 60 mm.; breadth, 12 mm. Color, dirty white. Body very flat,
in bad condition, more or less eviscerated. Tentacles wanting. Dorsally there
are six rows of conical papillae, of which two series are along each margin; all
the papillae look rubbed but they probably never had very long tips. Arrange-
ment of pedicels on ventral surface not distinguishable but there were probably
none in midventral ambulacrum at least anteriorly. Marginal papillae smaller
and forming a marginal fringe anteriorly. Mouth ventral. Anus dorsal.

Caleareous particles remarkably small and quite characteristic. They

1 parvispiculatus = provided with little spicules, in reference to the small size of the caleareous
particles.

138 DEIMATIDAE.

usually have 4 rays or arms (Plate 4, fig. 7) but often there are 5 or more (Plate 4,

fig. 8); the arms are flat, perforated with several holes at their enlarged tips,

and occasionally have little spines on the sides. The whole spicule is rarely

200 « long, while somewhat similar spicules in S. protectum are about 700 u long.

Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 36’ W., 2,370 fms. Bott. temp. 35.3°. Fne. gn.
m., mang. nod.

One specimen.

This species is readily distinguished from other known species of the genus
by the very small and characteristic spicules. It is unfortunate that the con-
dition of the specimen does not permit a better knowledge of its external features
and internal anatomy.

Scotodeima setigerum.

Lupwia, 1893. Bull. M. C. Z., 24, p. 109.

Although these specimens are in fairly good condition, they contribute
nothing of importance to Ludwig’s full account (1894, Mem. M. C. Z., 17, p.
74-79). They range in length from 55 to 88 mm.

Station 4647. Eastern Tropical Pacific, 4° 33’ S., 87° 42’ 30” W., 2,005 fms. Bott. temp. 35.5°. Lt. gy.
and br. glob. oz.

Station 4649. Eastern Tropical Pacific, 5° 17’ S., 85° 19’ 30’ W., 2,235 fms. Bott. temp. 35.4°. Fne.
stky. gr. m.

Seventeen specimens.

Laetmophasma fecundum.
Lupwie, 1893. Bull. M.C. Z., 24, p. 109.

The specimen, about 50 mm. long, is in such wretched condition that there
is little certainty about the identification. But there is no doubt that some
at least, of the now more or less decalcified, deposits were wheels like those

of L. fecundum and there is nothing improbable about the specimen represent-
ing that species.

Station 4653. West of Peru, about 17 miles, 5° 47’S., 81° 24’ W., 536 fms. Bott. temp. 41.3°. Dk. br.
gy. shore m.

One specimen.

Capheira sulcata.
Lupwie, 1893. Bull. M. C. Z., 24, p. 109.

The representatives of this species are in very bad condition indeed but
the calcareous particles agree well with Ludwig’s description and figures (1894,

TROPICAL PACIFIC HOLOTHURIOIDEA. 139

Mem. M. C. Z. 17, p. 100, plate 6, fig. 1-5). In one specimen it is possible

to find the tentacles and there seem to be only sixteen.

Station 4647. Eastern Tropical Pacific, 4° 33’ S., 87° 42’ 30” W., 2,005 fms. Bott. temp. 35.5°. Lt. gy.
and br. glob. oz.

Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 35’ 36” W., 2,370 fms. Bott. temp. 35.3°. Fne.
gn. m., mang. nod.

Two specimens.

PSYCHROPOTIDAE.

Euphronides dyscrita,! sp. nov.

Plate 2, fig. 3.

Length, 75 mm.; width, 17 mm. or more. Dorsal appendage, 18 mm.
long, 10 mm. wide at base, 5 mm. wide at tip; situated only 8 mm. from pos-
terior end of body; somewhat flattened and with tip rounded. Mouth and
anus, ventral. Tentacles apparently 18, but the number is hard to make out.
Color, yellow-brown above; deep purple below; tentacles, very deep purple.
There is a well-marked and frequently lobed margin but it is in too poor condi-
tion to permit its exact character to be determined.

Caleareous particles strongly arcuate 4-armed bodies with thorns but no
conspicuous spines either at center or elsewhere; arms 125 u long or longer
and occasionally twice that, but the large ones are very slender. Though
very abundant dorsally, the spicules are not crowded there; if present ventrally
they are more scattered and are concealed by the heavy pigmentation.

Station 4672. Peru: southwest of Palominos Light House, 88 miles. 2,845 fms. Bott. temp. 35.2°.
Fne. dk. br. infus. m.

Two specimens.

The holotype is in poor condition but the paratype is much worse and gives
no assistance as to the generic and specific characters. It is light gray above
with a brownish tinge but most of the external layer of skin is rubbed off. It
shows the well-marked, lobed margin but lacks the dorsal appendage or at best,
possesses but a fragment. The species looks like a short-tailed Psychropotes
but the appendage is so short and the calcareous particles are so strongly arcuate,
it seems better placed in Euphronides. The position of the dorsal appendage,
and the calcareous particles serve to distinguish it from any other member of
the genus.

1 6écxpiros= hard to determine, in reference to the doubtful generic position.

140 PSYCHROPOTIDAE.

Euphronides verrucosa.
Plate 1, fig. 2.
Lupwie, 1893. Bull. M. C. Z. 24, p. 107.

The representative, from station 4742, of this fine species is in fairly good
condition and is a very large one, nearly 200 mm. long by 50 mm. wide. The
colors in life are shown on Plate 1, but in the preserved specimen, the lower sur-
face is very dark purple while the upper side is light, dull rose-purple. There
are only sixteen tentacles. The characteristic calcareous spicules of the dor-
sal side are very conspicuous.

The specimen from station 17 is labeled by Mitsukuri “Euphronides bifur-
cata K. & V.” and is accompanied by the following note :—

“Specimen very much contracted and distorted. 16 tentacles. A little behind the posterior, and
one-third of the total length on the dorsal surface, 1 pair of not very long nor very large appendages,
1.lcm.long. 2 more pairs of much smaller appendages in front. At the dorso-ventral border, irregular
lobed brim. Body not very flat. Posterior part dorsal high. Ventral surface sole-like, flat. A row
of paired pedicels on the median ventral ambulacrum. On the dorsal, a number of warts, each sup-
ported by one four-branched spicule, from which the central needle projects.”

I have examined the specimen with great care but fail to find any dorsal
appendages nor can I distinguish the specimen in any adequate way from that
from station 4742 which I have referred to verrucosa. Whether Mitsukuri
made a mistake, or whether the mistake is mine, or whether bifurcata K. & V.
is identical with verrucosa Ludwig, more material alone can determine.
eee Eastern Tropical Pacific, 0° 50’ N., 137° 54’ W., 2,463 fms. Bott. temp.? Lt. yel.-gy.

glob. oz.

Station 4742. Eastern Tropical Pacific, 0’ 3’ 24” N., 117° 15’ 48” W., 2,320 fms. Bott. temp. 34.3°.
Fne. It. gy. glob. oz.

Two specimens.

Psychropotes raripes.
Plate 1, fig. 1.

Lupwic, 1893. Bull. M. C. Z., 24, p. 107.

The two representatives of this species are very big adults and are much
the largest deep-water holothurians in the collection. The specimen from
4658 is in remarkably perfect condition; the body is 170 mm. long, with the
tail 110 mm. in addition; the maximum width for the body, as well as for the
tail, which has convex lateral margins, is 45 mm. The tail is very flat and
distinctly notched at tip. The general color is gray above becoming purple
below, with the lower surface of the tail reddish ; tentacles purple. The
specimen from 4721 (Plate 1, fig. 1) is not in as fine condition but is still

TROPICAL PACIFIC HOLOTHURIOIDEA. 141

larger; the body, 220 mm., the tail 180 mm., and the width 50 mm. Mr.
Agassiz states that in life this specimen was 55 cm. long. The tip of the tail
is less distinctly notched than in the other specimen. The color is violet much
faded dorsally, where it is almost gray; the tentacles are brown.

Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 36’ W., 2,370 fms. Bott. temp. 35.3°. Fne. gn.
m., mang. nod.

Station 4721. Eastern Tropical Pacific, 8° 7’ 30’ S., 104° 10’ 30” W., 2,084 fms. Bott. temp.? Lt. br.
glob. oz.

Two specimens.

Benthodytes glutinosa.
Plate 2, fig. 1.

R. Perrier, 1896. Compt. Rend., 123, p. 903.

This species, originally described from the Atlantic, has since been recorded
from the Indian Ocean by Koehler and Vaney. The present specimen appears
to agree with these latter in the entire absence of spicules. Otherwise the agree-
ment with Perrier’s later, fuller description and figures (1902, TRAVAILLEUR et
TALISMAN Hol., p. 462; plate 13, fig. 5 and plate 20, fig. 31) is very close. The
differences between glutinosa and typica do not seem to be very weighty and it
is probable that the two are identical.

Station 4647. Eastern Tropical Pacific, 4° 33’ S., 87° 42’ 30” W., 2,005 fms. Bott. temp. 35.5°. Lt. gy.
and br. glob. oz.

One specimen.

Benthodytes regularis,' sp. nov.
Plate 2, fig. 2.

Length, 105 mm.; thickness about 15 mm., but when both margins are
spread flat, the width is 22 mm. Seen from below the appearance is much
like Théel’s figure of B. sanguinolenta var. marginata (1886, CHALLENGER
Hol., plate 25, fig. 2) but the upper surface is very different from that of mar-
ginata. On each dorsal ambulacrum is a series of fourteen or fifteen papillae
in a single row; these begin 25 mm. back of anterior end of body, are of nearly
uniform size and quite evenly spaced; each is about 2-2.5 mm. high by 1.5 mm.
in basal diameter; the form is bluntly conical. Mouth ventral but anus
dorsal. Anterior end quite flattened. Midventral line of pedicels distinct but
they are small and fully retracted; they are wanting on the anterior region for
a distance-of 20 mm. or more. Tentacles not permitting an accurate count,

1 regularis = according to rule, in reference to the regular arrangement of the dorsal papillae.

142 PSYCHROPOTIDAE.

“

probably fifteen but perhaps only twelve. Color, dull purplish gray; tentacles,
margin (at least orally) and midventral series of pedicels, deep purple.
Caleareous particles apparently wanting ventrally but scatteringly present

dorsally; they have the form of crosses with nearly equal, slender, thorny arms;
each cross is about 125» across but here and there were fragments of larger
crosses at least 250 » across. The outer layer of skin is badly rubbed off and -
as the crosses are in this layer, it is probable the fragmentary condition of the
larger crosses is due to rough treatment in the trawl. Perhaps the absence of

spicules ventrally is due to the same cause.

Station 4649. Eastern Tropical Pacific, 5° 17’ S., 85° 19’ 30” W., 2,235 fms. Bott. temp. 35.4°. Fne.
stky. gr. m.

One specimen.

This species appears to be well characterized by the regular arrangement
of the conspicuous dorsal papillae but the species of Benthodytes are most per-
plexing, particularly as they usually lack spicules or possess only such as are
not very distinctive. Specific limits within the genus, as at present drawn,
must be considered purely tentative.

Benthodytes sanguinolenta.
TuéeL, 1881. CHALLENGER Hol., pt. 1, p. 104.

This species is a convenient catch-all for specimens which are more or less
elongated, have no calcareous particles, and lack any other distinctive feature.
Whether more than a single species has been, or is here, listed under the name,
it is impossible to say, owing to the almost uniformly bad condition of the
material. The specimens from the following stations are from 50-80 mm.
long and hence probably young, excepting one in fairly good condition, which is
140 mm. long by 15 mm. thick. The specimen from 4740 appears to have
only thirteen tentacles.

Station 4651. Peru: west of Aguja Point, 111 miles. 2,222fms. Bott. temp. 35.4°. Fne. stky. gy. m.

Station 4658. Eastern Tropical Pacific, 8° 30’ S., 85° 36’ W., 2,370fms. Bott. temp. 35.3°. Fne. gn. m.
mang. nod.

Station 4672. Peru: southwest of Palominos Light House, 88 miles. 2,845 fms. Bott. temp. 35.2°.
Fne. dk. br. infus. m.

Station 4732. Eastern Tropical Pacific, 16° 32’ 30’ S., 119° 59’ W., 2,012 fms. Bott. temp. 34.8°.
Lt. gy. glob. oz.

Station 4740. Eastern Tropical Pacific, 9° 2’ S., 123° 20’ W., 2,422 fms. Bott. temp. 34.2°. Dk. gy.
glob. and rad. oz.

Eleven specimens.

TROPICAL PACIFIC HOLOTHURIOIDEA. 143

HOLOTHURUDAE.

Mesothuria megapoda,' sp. nov.
Plate 4, fig. 9, 10.

Length about 40 mm. Color, pinkish white. Eviscerated and in bad
condition so even the generic position is not certain, but the calcareous tables
show such similarity to those of M. murrayi and M. multipes that there is little
doubt the specimen represents a species of Mesothuria. Body rather uniformly
covered with large pedicels, 2-3 mm. long and .50-.75 mm. in diameter; there
is no arrangement in series or bands, nor are any of the pedicels conspicuously
larger than the others. There are no supporting rods in the pedicels but there
are well-developed terminal plates.

Calcareous particles consist of very numerous tables (Plate 4, fig. 9) with
spires 100-135 » high; the three rods making up the spire are enlarged, curved
outwards and rough at the tip. The disks (Plate 4, fig. 10) are 150-200 u across
and are perforated with seven nearly equal holes, one at center with six around
it; while they are not all exactly alike, they exhibit little diversity.

Station 4742. Eastern Tropical Pacific, 0° 3’ 24’”’ N., 117° 15’ 48” W., 2,320 fms. Bott. temp. 34.3°.
Fne. It. gy. glob. oz.

One specimen.

Although the specimen is in such poor condition its specific characters
are well marked. It is distinguished at once from M. multipes by the larger
pedicels, the presence of a well-developed terminal plate and the larger, lower
tables. In multipes, the disks of the tables are only 75-100 u across, while
the spires are much more than that. From M. murrayi, megapoda may be
readily distinguished by the uniform and large size of the pedicels and by the
_ difference in the tables. In murrayi, the disks are only 70-120 u» across but
have more numerous perforations.

Mesothuria multipes.

Mesites multipes Lupwic, 1893. Bull. M. C. Z., 24, p. 106.
Mesothuria multipes Lupwic, 1894. Mem. M. C. Z., 17, p. 31.

The specimen at hand has eviscerated so nothing can be said of its internal
anatomy. Otherwise it agrees well with Ludwig’s description except that the
tentacles are very dark colored, deep purplish. It is 60 mm. long.

1 ueyaro60s= having large feet, in reference to the unusually large pedicels.

144 HOLOTHURIIDAE.

Station 4656. Eastern Tropical Pacific, 6° 54” 36’ S., 83° 34’ 18’” W., 2,222 fms. Bott. temp. 35.2°.

Fne. gn. m., mang. nod.
One specimen.
Mesothuria multipora,! sp. nov.

Plate 4, fig. 11-13.

Length, 140 mm.; diameter, about 50 mm. Color, gray. Internal
anatomical details not definable as the specimen has eviscerated. Pedicels
scattered all over body, but most sparsely dorsally; dorsal pedicels about
1 mm. long by .25 mm. in diameter; the pedicels are much more numerous and
twice as large along the sides. Skin in close, horizontal, nearly black folds
along each side, forming a fairly distinct border between dorsal and ventral
surfaces.

Caleareous particles present in the form of tables (Plate 4, fig. 11) alone.
These are all of the same type and show diversity chiefly in the number of per-
forations in the disk; spire with one cross-beam, about 75 high and 50x
across the top (Plate 4, fig. 13) which bears about sixteen teeth; disk (Plate 4,
fig. 12) squarish, 200 » across, with a somewhat square central hole and thirty

to fifty more or less circular perforations of small size.
Station 74. Tahiti: 4.8 miles N.,82° W. from Point Venus, 772 (?) fms. Bottomtemp.? Fne. vol.s. (?).

One specimen.

This specimen was labeled by Professor Mitsukuri “ Mesothuria intesti-
nalis Asc. Rathke (Hol. Verrillii Théel).” I have compared it with both
intestinalis from Norway and cotypes of verrilli from the West Indies, and the
difference in the tables is striking and apparently constant. I am satisfied
that verrilli is a perfectly: valid species and that the present Tahitian form is
entirely distinct from either the European or the West Indian species.

Synallactes aenigma.
Plate 3, fig. 4.

Lupwic, 1893. Bull. M.C. Z., 24, p. 106 (nomen nudum). 1894, Mem. M.C. Z., 17, p. 26.

This seems to be one of the characteristic species of the Eastern Tropical
Pacific and the present series throws no little light on its structure and varia-
bility. Instead of merely eviscerating, this species seems to have also the unusual
habit of actually throwing off the skin. Either as a result of rough treatment
in the trawl or because of the decreased pressure at the surface, or perhaps for
both reasons, the skin, which is quite thick and tough splits down the middorsal

* multtporus = having many pores, in reference to the disk of the calcareous tables.

TROPICAL PACIFIC HOLOTHURIOIDEA. 145

line and becomes entirely detached from the body-muscles, which are con-
tracted into a firm cylindrical mass, evisceration having previously occurred.
The skin around the mouth and the tentacles remain on the muscular mass.

The specimens at hand range from twenty-eight to nearly 100 mm. in length
and show great diversity in the size, number and conspicuousness of the pedi-
cels and papillae. The pedicels in the midventral radius may be so few and
small, that they would readily escape notice but they may be fairly conspicu-
ous. In one specimen there is scarcely a trace of dorsal papillae and even
the marginal ones are indistinct, while in a slightly smaller specimen (Plate 3,
fig. 4) from the same station, practically the whole dorsal surface is occupied
by a double series of large conical papillae in each ambulacrum and a marginal
series on each side.

In the larger of two specimens from station 4651, the calcareous ring is
well developed and resembles that of S. alexandri as described by Ludwig, while
in the smaller one, I fail to find any calcareous ring at all, the condition which
Ludwig found in his specimens of aenigma. Even the calcareous tables show
some diversity; in a specimen from 4656, the tables are rather slender and have
a smooth spire while in another from the same station, the tables are stouter
and have rough spires.

Probably many of the differences shown by preserved specimens, in form,
size, and appearance of pedicels and papillae are artificial, but there can be
little doubt that the species does show more or less diversity in nearly all its
characters. There are also changes due to age which cannot be ignored. Young
specimens have remarkably slender tables; the basal arms are very slender and
the spire, about twice the basal diameter, is very long, slender, and thorny.
Apparently with age, the spires become stouter and smoother as well as shorter,
and the basal arms are noticeably thicker.

Station 4649. Eastern Tropical Pacific, 5° 17’ S., 85° 19’ 30” W., 2,235 fms. Bott. temp. 35.4°. Fne.
stky. gr. m.

Station 4651. Peru: west of Aguja Point, 111 miles. 2,222fms. Bott. temp. 35.4°. Stky. fne. gy.s.,
trace of shore-mud.

Station 4656. Eastern Tropical Pacific, 6° 54’ 36” S., 83° 34’ 18” W., 2,222 fms. Bott. temp. 35.2°.
Fne. gn. m., mang. nod.

Eight specimens.

Synallactes triplax,! sp. nov.
Plate 4, fig. 14-17.
Length, 60 mm.; diameter, less than 20 mm. Color, pale gray, nearly
white. General appearance much as in S. aenigma but pedicels larger and

1 +pirdat = triple, in reference to the triradiate calcareous tables.

146 HOLOTHURIIDAE.

more conspicuous on ventral surface; there are two well-marked series in each
of the three ventral ambulacra. In each of the dorsal ambulacra is a double
row of conical papillae. Tentacles twenty, rather small. Calcareous ring very
well developed; interradial pieces wider than high with a conspicuous anterior
point; radial pieces much larger with a strongly concave posterior margin
and two conspicuous, truncate anterior projections. No ampullae on the
tentacles. Respiratory trees well developed. Genital glands in two tufts,
one on each side of the dorsal mesentery. Anus terminal and not sunken in
a vertical furrow.

Caleareous particles, crowded tables with simple spires (Plate 4, fig. 14)
of three rods united by three cross-bars but with the points free, straight and
parallel; disks triradiate, in the typical condition (Plate 4, fig. 15) with three
large oval perforations and a second series of three somewhat smaller holes
alternating with them; usually, however, a third, often a fourth and not rarely
a fifth series of perforations is present (fig. 16); diameter of disk 150-500 u,
but usually 250-400; height of spire equals disk-diameter or somewhat less.
In many of the larger tables, the primary perforations are never closed in dis-
tally, so the disk remains a triradiate plate (Plate 4, fig. 17), with the outer end
of each bar dichotomously branched and the final expansion perforated with
1-4 holes.

Station 4642. Galapagos Islands: Hood Island, 4 miles southeast of Ripple Point. 300 fms. Bott.
temp. 48.6°. Brk. sh., glob.

One specimen.

This species is notable for the relatively shallow water in which it lives and
the high bottom temperature of its habitat. It is closely related to several of
the recently described Japanese species of Synallactes, particularly to discoidalis
Mitsukuri. It differs from this form, however, in having fewer papillae and
pedicels; four rows of papillae instead of six, and only two series of midventral
pedicels instead of four to six. The tables are larger than in discoidalis, in
which species the disk is only about 175 u across, and the spire is quite different,
as the three rods composing it are more or less fused in the Japanese species.

Pseudostichopus mollis.
THEEL, 1886. CHALLENGER Hol., pt. 2, p. 169.

These specimens are 20-125 mm. in length and show the usual diversity
of this species in the condition of the body-wall and its surface. Some are firm,

TROPICAL PACIFIC HOLOTHURIOIDEA. 147

almost hard with a perfectly smooth surface, showing no pedicels or adherent

particles; others are less firm and show numerous pedicels and more or less

adherent foreign material; still others are soft and flaccid, often with so much

adherent material as to obscure the pedicels. All agree, however, in the absence

of calcareous particles in the skin and in the presence of the vertical groove for

the anus. The species of Pseudostichopus are perplexing but I see no good

reason why these specimens should not all be referred to mollis. The differences

between them are almost certainly artificial, except such as are due to age.

Station 4641. Galapagos Islands: Hood Island, 12 miles southeast of Ripple Point. 633 fms. — Bott.
temp. 39.5°. Lt. gy. glob. oz.

Station 4647. Eastern Tropical Pacific, 4° 33’ S., 87° 42’ 30” W., 2,005 fms. Bott. temp. 35.5°. Lt. gy.
and br. glob. oz.

Station 4656. Eastern Tropical Pacific, 6° 54’ 36” S., 83° 34’ 18’ W., 2,222 fms. Bott. temp. 35.2°.
Fne. gn. m., mang. nod.

Station 4672. Peru: southwest of Palominos Light House, 88 miles. 2,845 fms. Bott. temp. 35.2°.
Fne. dk. br. infus. m.

Twelve specimens.
Stichopus chloronotus.
Branpt, 1835. Prod. descr. Anim., p. 250.

A single specimen of this wide-spread Indopacific species was taken at Uola
Caroline Islands, February 15, 1900.

r

Stichopus variegatus.

Semper, 1868. Holothurien, p. 73.

It is a matter of no little interest that this well-known Indopacific species
was found at Easter Island, December 21, 1904. The known range is thus
extended many hundred miles to the southeastward. The specimen is a large
one but strongly contracted.

Holothuria arenicola.

Spmper, 1868. Holothurien, p. 81.

A single specimen about 80 mm. long was taken at Perico Island, Panama,
October 26, 1904. The species was previously known from the Galapagos and
its occurrence at Panama is therefore not surprising, but it is quite possible
that comparison of good series from the East Indies, the Galapagos, and Panama
will show specific differences not at present suspected. Fisher (1907, Proc.
U. S. Nat. Mus., 32, p. 664) has pointed out that the name maculata Brandt
which has long priority over arenicola, is invalidated by Holothuria maculata

148 HOLOTHURIIDAE.

Chamisso and Eysenhardt, 1821. The fact needs emphasis, as Ludwig’s very
careful and important revision of Brandt’s species has so generally validated
Brandt’s names.

Holothuria atra.
Jarcer, 1833. De Holothuriis, p. 22.

This very abundant species is represented in both the collections. It was
taken at Rangiroa, Paumotu Islands, September 21, 1899 and at Manga Reva,
Paumotu Islands, February 3, 1905. The latter would seem to be the farthest
to the southeast that the species is known to range.

Three specimens.

Holothuria cinerascens.

Stichopus (Gymnochirola) cinerascens BRANDT, 1835. Prod. descr. Anim., p. 251.
Holothuria cinerascens LAMPERT, 1885. Die Seewalzen, p. 82.

A single specimen of this species, long known under Selenka’s familiar
name pulchella, was taken on the coral reef at Manga Reva, February 3, 1905.
The record extends the known range far to the southeast.

Holothuria difficilis.
Semper, 1868. Holothurien, p. 92.

Fifteen small specimens which seems to be this species were taken at
Makemo, Paumotu Islands, October 20, 1899. The resemblance in the general
appearance and in the calcareous particles with those of H. captiva, H. frequen-
tiamensis, and Actinopyga parvula are very striking, and suggest that the four
names represent a single species. Examination of good series of specimens
from numerous localities will be necessary to get the matter cleared up.

Holothuria imitans.

one

Lupwia, 1875. Arb. Zool. Zoot. Inst. Wurzburg, 2, p. 109.

There is a deep brown holothurian, 110 mm. long by 30 mm. in diameter,
in the 1904-1905 collection labeled “‘114.’’ I am unable to find any interpre-
tation of this label for on November 4, if the figures are a date, the ALBATROSS
was dredging in more than 1,700 fms. between Panama and the Galapagos,
and the specimen is obviously a littoral form. The calcareous particles are
tables alone, save for supporting rods in the numerous pedicels which cover
the whole body. The tables are very different from those of languens and while
they also differ from Ludwig’s figure of the tables of imitans, they are so much

TROPICAL PACIFIC HOLOTHURIOIDEA. 149

nearer the latter, I refer the specimen to that species, though not without some
doubt. The tables have an annular disk with eight distinct spines, and a dis-
tinctly smaller top with twelve to twenty teeth; the rods composing the spire
diverge basally, not converging as in languens.

Holothuria impatiens.

Fistularia impatiens ForsKA&u, 1775. Desc. Anim., p. 121.
Holothuria impatiens GMELIN, 1788. Syst. Nat. Linn. ed. 13, p. 3,142.

This is another of the common wide-spread Indopacifie species occurring
in both collections. It was taken in the Paumotu Islands at Fakarava, October
12, 1899, and again at Makemo, October 20. On February 3, 1905, a specimen
was found at Manga Reva, Paumotus, notable for its color, seal-brown with the
papillae cream-color. The specimens are all much contracted. Four specimens.

Holothuria languens.

SELENKA, 1867. Zeits. f. w. Zool., 17, p. 335.

This well-known Panamiec species is represented in the 1904-1905 collec-
tion by three specimens, 15~40 mm. long, all much contracted and in poor
condition. Two are from Taboguilla Island, Panama, October 31, 1904, and
the third was collected at Perico Island, Panama, October 26, 1904.

Holothuria leucospilota.

Stichopus (Gymnochirota) leucospilota BRANDT, 1835. Prod. deser. Anim., p. 251.
Holothuria leucospilota LAMPERT, 1885. Die Seewalzen, p. 71.

This species, so long known under Selenka’s familiar name, vagabunda,
must unquestionably bear Brandt’s much earlier name, though both Lampert
and Théel refused to recognize such a change. Four specimens were taken
during the voyage of 1899-1900, the localities being :—

Rangiroa, Paumotus, September 21, 1899.

Maketea, Paumotus, October 6, 1899.

Fakarava, Paumotus, October 2, 1899.
Ponape, Caroline Islands, February 12, 1900.

Holothuria lubrica.
SELENKA, 1867. Zeits. f. w. Zool., 17, p. 329.
This well-known Panamic species is represented in the 1904-1905 collec-
tion by five specimens. There is some diversity of color but the general shade
is brown, darkest dorsally; in one specimen, blackish spots on the dorsal side

150 HOLOTHURIIDAE.

are fairly distinct. “As a rule the distinction between the dorsal and ventral
surfaces is very marked but this is not always the case. The specimens were
taken at Taboquilla and Perico Islands, Panama, in October, 1904.

Holothuria marenzelleri.
Lupwic, 1883. Ber. d. oberh. Ges. f. Naturk., 22, p. 167.
\ single specimen was taken at Chatham Island, in the Galapagos, in Janu-
ary 1905. It measures 100 mm. in length by 35-40 mm, in diameter. The
species has been recorded previously from the Galapagos Islands, although

it was originally described from the East Indies.

Holothuria monocaria.
Lesson, 1830. Cent. Zool., p. 225.

The specimens which I refer (though not without hesitation) to this com-
mon species are quite young, one about 40 mm., the other only 11 mm. long.
The larger is nearly white and is possibly from Tahiti but nothing is certain
as to the locality beyond the fact that the specimen was collected by the 1899-
1900 expedition. There are very few buttons in the skin and the tables show
considerable diversity of form. The smaller specimen is also nearly white.
It was taken October 12, 1899, at Fakarava, Paumotu Islands. The tables
are well formed but diversified with eight to thirteen marginal holes in the disk.
There are apparently no buttons in the skin. If these specimens really are
monocaria it would seem to be probable that tables arise some time before
buttons and that the buttons only gradually become so numerous as to form
the layer present in adults. But of course, only a series of indubitable growth-
stages can determine whether this is the case.

Holothuria pardalis.

SELENKA, 1867. Zeits. f. w. Zool., 17, p. 336.
A single specimen taken October 20, 1899 at Makemo, Paumotu Islands,

seems to belong to this species but the condition is poor and the calcareous
particles are so corroded that it is impossible to be sure of the identification.

Holothuria scabra.

JAEGER, 1833. De Holothuriis, p. 23.

A single specimen of moderate size was taken at Guam, Ladrone Islands,
February 27, 1900.

TROPICAL PACIFIC HOLOTHURIOIDEA. 151

Actinopyga lecanora.

Miilleria lecanora JAEGER, 1833. De Holothuriis, p. 18.
Actinopyga lecanora BRronn, 1860. Thierreich, 3, p. 403.

A specimen of this wide-spread Indopacific species was taken February 3,
1905, at Manga Reva, Paumotu Islands, on the coral reef, thus extending the
known range far to the southeastward. The specimen is now very strongly

contracted but the specific characters are distinguishable without difficulty.

Actinopyga mauritiana.

Miillleria mauritiana Quoy ET GaImMaARD, 1833. AsTRoLABE Zooph., p. 138.
Actinopyga mauritiana FisHEeR, 1907. Proc. U.S. Nat. Mus., 32, p. 648.

It is rather remarkable that while the 1899-1900 expedition brought home
six specimens of this well-known species from at least four islands in the Society
and Paumotu groups, the species was apparently not met with by the later
expedition, although the latter took the preceding species at Manga Reva.
The specimens are chiefly large adults but the one from Fakarava is only 20
mm. long and one from Papeete is less than half grown. The latter is notable
for being colored like lecanora, the area around the anus being abruptly and con-
spicuously lighter than the ground-color of the body. The smallest specimen
is of unusual interest because there are few grains in the ventral skin and the
rods there are larger than those of the dorsal surface. If the identification of
this specimen is correct, the characteristic ventral grains do not appear until
the animal is more than 20 mm. long. No doubt the growth-stages of this Acti-
nopyga would afford a very interesting study. The specimens in the present
collection were taken at :—

Rangiroa, Paumotus, September 23, 1899.
Papeete, Tahiti, Society Islands, September 28, 1899.
Makatea, Paumotus, October 6, 1899.
Fakarava, Paumotus, October 12, 1899.
Actinopyga parvula.

Milleria parvula SELENKA, 1867. Zeits. f. w. Zool., 17, p. 314.
Actinopyga parvula Fisuer, 1907. Proc. U.S. Nat. Mus., 32, p. 645.

There are sixteen small specimens 15-35 mm. long, collected at Easter
Island, December 20, 1904, which seem to belong to this remarkably wide-spread
species. The color ranges from brown to almost black dorsally, but is gener-
ally lighter ventrally. Some specimens show distinct blotches of darker color
on the back. All the specimens have anal teeth but all five teeth are not equally
developed in every case. This little holothurian is certainly a puzzle. It

152 OPHIURANS.

occurs in the West Indian region where Holothuria captiva, from which it can
scarcely be distinguished except by the anal teeth, is common. It occurs in
the mienasts region with Holothuria dificilis from which again the anal teeth
are its one distinguishing character. On the other hand, it is utterly unlike
any other Actinopyga save for the presence of the anal teeth. Pearsons is
divest certainly right in removing it from Actinopyga but he throws no light
on the problem of its relation to the species of Holothuria mentioned. Pos-
sibly the presence of anal teeth is, in this case, not even a valid specific character
but it is hard to believe this is the case. At any rate, the occurrence of this
perplexing form, originally described from Florida, on the shores of Easter

Island is a matter of unusual interest.

Summary of the Echinoderms collected by the Agassiz-Albatross Tropical Pacific
Expeditions of 1891, 1899-1900 and 1904-1905.

As the present report is the last of those dealing with the Echinoderms
collected by Mr. Agassiz on his Tropical Pacific Expeditions, it is fitting that
the chief additions to our knowledge of the taxonomy of the Echinodermata
should be summarized.

The Crrvorps proved to be the least abundant of the five classes and only
nine species were taken. Of these two were unidentifiable but six of the
others were new. There is no record of the number of specimens. The most
notable of the crinoids are the two stalked forms Bathycrinus equatorialis A. H.
Clark and Calamocrinus diomedae A. Agassiz. The latter, one of the most
notable stalked crinoids as yet taken, was made the subject of a detailed mono-
graph (Agassiz, 1892, Mem. M. C. Z. 17, no. 2).

The AstERorps were fairly numerous but there were few species of ex-
traordinary interest. In all more than 1,300 specimens were brought home,
representing ninety species, of which sixty-nine were new. Of new genera,
five were established. The most notable forms are probably the two species
of the new genus Albatrossia, the numerous species of Hymenaster, and Zoro-
aster, and the Brisingidae.

The OpHIURANS were numerous both in specimens and species but unfor-
tunately there is no complete record of the number of specimens. There were
at least ninety-seven species taken, and of these sixty were new. One new
genus was described based on this material. The most noteworthy brittle-stars
are Gymnophiura mollis, Sigsbeia lineata, and Ophioderma pentacantha.

TROPICAL PACIFIC HOLOTHURIOIDEA. 153

The Ecuini were represented by forty species, a very large number in pro-
portion to the total number of species known. There is no means of determin-
ing how many specimens were taken as there are no available records on this
point. Ten of the species brought home are common littoral species of wide
range but of the other thirty, no fewer than twenty-nine were new when taken
and all but one of these is from deep water. Undoubtedly the most remarkable
sea-urchin discovered is Pilematechinus rathbuni, but Centrocidaris doederleini,
Dialithocidaris gemmifera, Plexechinus cinctus, and Phryssocystis aculeata are
also of exceptional interest, each being the type of a new genus.

The HoLoTHuRiaNns were the most generally met with of any of the classes
of echinoderms and the records show that 953 were in the collections brought
home. These represented seventy-nine different species many of which are com-
mon littoral forms of wide range but forty-three were described as new. Of
course the most remarkable is the extraordinary Pelagothuria natatriz, sole
representative of a pelagic family and the only echinoderm known to be truly
pelagic in adult life. Other noteworthy holothurians, knowledge of which we
owe to these explorations of the ALBaTROss, are two abyssal species of Myrio-
trochus, the huge Psychropotes raripes, Laetmophasma fecundum, Capheira sulcata,
and Echinocucumis bitentaculata.

Summing up for the five classes, we find that the ALBaTrRoss, on her three
Tropical Pacific expeditions, collected several thousand echinoderms, repre-
senting 315 species, of which 207, or more than two thirds, were new. The
increase in our knowledge of the morphology and distribution, both geographi-
cal and bathymetrical, of the group, which we owe to these expeditions, cannot
be summarized in this rough and ready way, but one cannot turn the pages
of the following reports, wherein they are treated, without realizing how great
it is.

Iist of the Reports based wholly or in part on the Echinoderms collected by the
Atpatross Tropical Pacific Expeditions in 1891, 1899-1900, and in
1904-19065

CRINOIDS.
A. Agassiz, 1892. Mem. M. C. Z., 17, no. 2, p. 1-95, pl. 1-32.
C. Hartlaub, 1895. Bull. M. C. Z., 27, p. 127-152, pl. 1-4.
A. H. Clark, 1908. Bull. M. C. Z., 51, p. 231-248, pl. 1, 2.
ASTEROIDS.
H. Ludwig, 1905. Mem. M. C. Z., 32, 304 pp., pl. 1-36.

154 HOLOTHURIANS.
H. Ludwig, 1907. Zool. anz., 31, p. 312-319.
H. L. Clark, 1920. Mem. M. C. Z., 39, p. 69-114, pl. 1-6. °

OPHIURANS.
C. F. Liitken and T. Mortensen, 1899.

pl. 1-28.
H. L. Clark, 1917. Bull. M.C. Z., 61, p. 427-453, pl. 1-5.

Mem. M. C. Z., 23, p. 93-207,

EcuHINI.

A. Agassiz, 1898. Bull. M. C. Z., 32, p. 69-86, 14 pls.

A. Agassiz, 1904. Mem. M.C. Z., 31, 253 pp., 112 pls.

A. Agassiz and H. L. Clark, 1907-1909. Mem. M. C. Z., 34,210 pp., pl. 1-89.

A. Agassiz, 1908. Mem. M. C. Z., 39, p. 1-34, 49 pls.

A. M. Westergren, 1911. Mem. M. C. Z., 39, p. 35-68, pl. 1-38.

H. L. Clark, 1912. Mem. M. C. Z., 34, p. 205-883, pl. 90-121.

H. L. Clark, 1914-1917. Mem. M. C. Z., 46, p. 1-283, pl. 122-161.
HOLOTHURIANS. ;

H. Ludwig, 1893. Zool. anz., 16, p. 177-186. Bull. M. C. Z., 24, p. 103-

114.
H. Ludwig, 1894. Mem. M.C. Z. 17, no. 3, p. 1-188, pl. 1-19.
H. L. Clark, 1920. Mem. M.C. Z., 39, p. 115-154, pl. 1-4.

EXPLANATION OF THE PLATES.

ba
a 4
SI =
PLATE 1. :
1. Psychropotes raripes Ludwig. =
Large adult from Station 4721, seen from the side. About one half natural size.

2. Euphronides verrucosa Ludwig.
Large adult from Station 4742, seen from above.

About two thirds natural size.

‘
.
=
.
£
< 2
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+ =
.
.

4A. Agassiz and AM Westergren del.

Ex1899-1900, 1904-05

o> - = A : i

PLATE 2.
1. Benthodytes glutinosa R. Perrier.
Adult from Station 4647, seen from below.

2. Benthodytes regularis H. L. Clark.
Holotype from Station 4649, seen from above.

3. Euphronides dyscrita H. L. Clark.
Adult, probably the holotype, from Station 4672, seen from above.

4. Periamma tetramerum H. L. Clark. -
Adult from Station 4670, seen from below.

5. Cucumaria abyssorum Théel.
Adult from Station 4649, seen from the side, the ventral surface to the left.

All figures supposed to be natural size.

EZ

7

HOLOTHURIOIDEA PLAT

Ex.1899-1900, 1904-05.

ROPICAIL PACIFIC

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yf re iy Re “ua é ~ =

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A Agassiz and AM Wesiereren del.

PLATE 3.

Molpadia holothurioides Cuvier? |)
Adult from Station 4672, seen from the side. The absence of a caudal appendage is perhaps due
to an accident. : - ;

Molpadia bathybia H. L. Clark. Sa
Paratype from Station 4670, seen from below. : 7

Parelpidia anamesa H. L. Clark. 2
Holotype from Station 4658, seen from below.

Synallactes aenigma Ludwig. : ia
Adult from Station 4649; the discarded and contracted skin seen from above. |

si > a,
Molpadia sp. ae

Drawn from a specimen, no longer extant, taken at Station 4630. _ t

Scotoplanes murrayi (Théel). is
Adult from Station 4651, seen from above. ; Es

All figures supposed to be natural size.

THURIOID

Tarrant
TLOLO

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PNININTS

7

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siz and A.M Westersren del

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1,2)

11-13.

14-17.

PLATE 4.

Chiridota aponocrita H. L. Clark.
1. Supporting-rods of tentacles. X 450.
2. Miliary granules. X 450.

Myriotrochus bathybius H. L. Clark.
Calcareous wheel. X 95.

Mpyriotrochus giganteus H. L. Clark.
Caleareous wheel. X 95.

Molpadia bathybia H. L. Clark.
Disks of tables. XX 95. ~
Spire of a table, from the side. X 95.

Scotodeima parvispiculatum H. L. Clark.
Caleareous particles. x 140.

Mesothuria megapoda H. L. Clark.
9. Table, seen from the side. > 95.
10. Disk of table. x 95.

Mesothuria multipora H. L. Clark.

11. Table, seen from the side. X 95.

12. Disk of table. xX 95.

13. Spire of table, seen from above. X 95.

Synallactes triplax H. L. Clark.

14. Typical table seen from the side. 95.

15. Disk of typical triradiate table. X< 95.
16. Disk of larger table. > 95.
17. Disk of an “unclosed” table. »X 95.

H.L. Oo

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