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CTENOPHORES

OF THE

ATLANTIC COAST OF NORTH AMERICA

BY
ALFRED GOLDSBOROUGH MAYER

Director of the Department of Marine Biology,
Carnegie Institution of Washington

WASHINGTON, D. C.
PUBLISHED BY THE CARNEGIE INSTITUTION OF WASHINGTON
1gi2 ae
(
Fs e

A2b32*\
CARNEGIE INSTITUTION OF WASHINGTON

PusxicaTion No. 162

Uupies of this Book
were first issued

MAR? 1912

PRESS OF J. B. LIPPINCOTT COMPANY
PHILADELPHIA, PA.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA.

By ALFRED GOLDSBOROUGH MAYER.

This research was begun in 1892 at the suggestion of Prof. Alexander
Agassiz, while I was a student in his excellently equipped marine labora-
tory at Newport, Rhode Island. Until 1900 Professor Agassiz did all
in his power to encourage these studies, and I now publish the final
results in the hope that by so doing I may present them as a tribute of
respect and gratitude to the memory of Alexander Agassiz to whose
generous aid and unselfish interest so many young men have owed their
impetus toward research in science.

It is a pleasure to express my appreciation of the kindness of the
Honorable Mr. A. W. Piccott, Minister of Marine and Fisheries of New-
foundland, who cordially extended toward me every personal and official
courtesy while I was engaged in the study of the ctenophores of the
Newfoundland coast in September, 1910.

During the past seven years at the Tortugas Laboratory of the Car-
negie Institution of Washington it has been my custom to go out upon
the ocean during periods of tropical calm, when the surface is unrippled,
and to dip up the Ctenophores in glass vessels and transfer them to the
laboratory for study. All but three of the species of Ctenophore described
from American North Atlantic waters have come under my observation,
and descriptions of these three, Lesueuria hyboptera, Ocyropsis maculata,
and Tyalfiella tristoma are introduced in order to present an account of
all ctenophore known from the Atlantic coast of North America. The
species herein described are as follows:

; Spzcrzs, * . Gmocrapuicat RANGE,
Mertensia ovum... ccc ccc cee ceeeeee Arctic to southern coast of New England.
* Pleurobrachia pileus..... 0.0... e ee North of Cape Cod in summer, driven south-
ward in winter.
5 brunnea sp. nov...... Coast of New Jersey.
Hormiphora plumosa.........0..-. Mediterranean and tropical Atlantic.
Tinerfe lactea sp. NOV......+...0.0. Tortugas, Florida
beehleri sp. nov............ Tortugas, Florida.
+ Lesueuria hyboptera (problematical). Coast of Massachusetts north of Cape Cod.
, Bolinopsis infundibulum. .......... Arctic to Cape Cod.
UU ED eta ee Wisi ace GOR eek Tropics, West Indies, Florida, Mediterranean.
' Mnemiopsis leidyi................. Vineyard Sound to South Carolina.
MCCYAGYL. 0... eee ee Tropics to South Carolina.
Ardent.......005- ....Chesapeake Bay to northern Florida,
Leucothea ochracea sp. nov...... -,,. Tortugas, Florida.
Ocyropsis crystallind...........6.. '. Tropical Atlantic.
MACUALA... eee eee Tropical Atlantic and Pacific.
Eurhamphea vexilligera........644. Mediterranean and tropical Atlantic.
A COSLUM VENETIS. Coco ccc cece ne ne Atlantic, Pacific, and Mediterranean,
Folia parallela....... 006s cece eee Mediterranean to tropical Atlantic.
Bero€ ovata... .. ccc cc cece Mediterranean, tropical and temperate Pacific.
and Atlantic.
Beroe CUCUMIS....0 0. vce Arctic Ocean to Cape Cod,
Tjalfiella tristoma......... 0.00 eee West Coast of Greenland.

2 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

It will be seen that there are 21 ctenophores known from the Atlantic
coast of North America. Of these, 6 are cold-water forms and do not
commonly range southward of New Jersey along our coast, although
Arctic forms are sometimes driven, by winter storms, as far south as
Cape Hatteras; 3 are intermediate and are found between the south-
ern shore of Cape Cod and northern Florida; 12 are tropical species,
some of which drift northward in summer to the region of Vineyard
Sound. Thus, along this whole stretch of coast, extending from the
Arctic regions to the tropics, we find only 21 species, while Chun records
20 from the Mediterranean.

In no part of the North American coast are ctenophores as plen-
tiful or as numerous in species as in the Bay of Naples, where 17
kinds were found by Chun. In contrast to this, the Tortugas region,
which is richer in number of species than any other part of the North
American coast, has but 12 kinds of ctenophores. In the tropics, how-
ever, one does not often see the great swarms of one or a few species which
are so commonly met with in the cold or Arctic waters. At Newport,
Rhode Island, the surface of the sea is sometimes covered for thousands
of square yards with great submerged rafts of Mnemiopsis leidyi, the
individuals touching one the other, and the same phenomenon occurs
with Pleurobrachia pileus or Bolinopsis infundibulum off the coast of
northern Maine. At Tortugas, Florida, on the contrary, dense swarms
of ctenophores are not seen, although more than twice as many species
are found in this tropical region than off the coast of Maine.

Of the 21 forms described in this paper, 4 are new to science and 7
have not hitherto been recorded with certainty from the American coast;
6 are Mediterranean species which extend across the tropical Atlantic
to the American coast. It is also of interest to see that 3 species, Pleu-
robrachia brunnea, Mnemiopsis leidyi, and M. gardeni are animals of the
temperate regions, never having been taken in Arctic or in tropical waters.

A list of all of the then-known species of ctenophores with an account
of their geographical ranges is given by Moser, 1909, in Ctenophoren der
deutsch. Stidpolar-Expedition, Bd. 11, Zool. 3, p. 123. This important
paper also gives a very complete list of references to literature upon
ctenophores.

It is unfortunate that the old and time-honored generic names Bo-
lina, Eucharis, Ocyroé, and Vexillum have been preoccupied and can not be
retained for Ctenophore, and the names Bolinopsis, Leucothea, Ocyropsis,
and Folia are suggested to replace them. Much asI regret the change,
if the rules demand it we should make it at once.

As is well known, the Ctenophore are biradially symmetrical animals
with a slit-like mouth at one pole, and at the opposite end of the body
an apical sense-organ consisting of a mass of lithocysts said to be com-
posed of phosphate of lime, and inclosed in a capsule the walls of which
are probably formed of fused cilia, the mass of lithocysts being sup-
ported upon 4 flat triangular plates composed of fused cilia. On both
sides of the apical sense-organ there is a long, narrow, elevated ridge of
epithelial cells which are probably sensory and constitute the pole-plate.

The mouth, which is at the opposite end of the body, is a long narrow
slit and leads into a laterally compressed chamber, the wide axis of which

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 3

is in the plane of the pole-plate, while its narrow axis is in the plane of
the tentacles when these are present. This buccal chamber is commonly
called the “stomach,” but its walls are of ectoderm and bear cilia, which
are especially well developed in the Beroide, where they occur in linear,
longitudinal areas extending from the lips inward. This chamber is
certainly a food receptacle, and we will call it the stomodzeum.

The stomodzum leads into the entodermal part of the gastric cav-
ity, a laterally compressed chamber called the funnel or infundibulum.
The wide axis of the funnel is perpendicular to that of the stomodeum
and it lies in the plane of the two tentacles to the basal-bulb of each
of which it sends a canal. It also sends a canal upward to the sense-organ,
and this axial vessel, which is called the funnel-tube, opens by a pair of
excretory pores on two diagonally opposite sides of the pole-plate. Inthe
Beroide there are two lateral funnel-tubes, one to each excretory pore.

Tr
1.

Fic. 1.—Diagram illustrating characters of central part of gastro-vascular
system of ctenophores.

Fic. 2.—Diagram showing character of canal-circuits in Lobate. Tentacles,
tentacular canals, ciliary combs, and auricles are omitted.

In addition to the two tentacular vessels and the axial funnel-tube,
the funnel gives rise to four interradial vessels, which arise typically at
an angle of 45° with the stomodzal and funnel axes. In the Cydippida,
however, the four interradial vessels do not arise directly from the funnel,
but the funnel-chamber gives rise to a pair of side tubes called the per-
radial vessels, pr, figs. 4 and 5, pages 11 and 12, from the sides of which
the four interradial canalsarise. In any event the four interradial canals
soon bifurcate and each of their eight adradial branches leads to a row of

4 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

ciliary combs beneath and along the line of which there extends a meri-
dional longitudinal vessel.

Two other vessels, the paragastric canals, arise from the funnel-
cavity in the tentacular plane and extend downward close to and along
the middle of the broad sides of the stomodzum.

As this canal-system is complex I have sought to make its arrange-
ment clear by presenting a diagram in figure 1, which should be con-
sidered seriously only in so far as it is diagrammatic, and should be
compared with figs. 4 and 5, which illustrate the conditions seen in
Pleurobrachia pileus. This diagram attempts to show a perspective view
of the gastro-vascular cavity. The mouth, m, leads into the laterally
flattened, slit-like cavity of the stomodeum, st; this in turn leads into
the laterally flattened infundibulum or funnel, 7, the flat side of which is
90° apart from the flat side of the stomodeum. The axial funnel-tube, 71,
leads upward from the funnel to open to the outside through the excre-
tory pores, ex. The long, narrow ridge of the pole-plate, p, lies in the same
plane as the stomodeum and 9o° apart from the axis through the funnel
and tentacles. The funnel, /, gives rise to two tentacular canals, t, two
paragastric canals, g, and four interradial canals,7. The four interradial
canals bifurcate and give rise to eight adradial branches, ad, which lead
to the meridional canals, which are not shown in this figure, but which
extend along under the combs of cilia.

In the Cydippide the eight meridional canals and the two paragas-
tric vessels end blindly near the oral end of the body, but in the higher
ctenophores of the orders Ganeshidz, Lobate, Cestide, and Beroide their
oral ends fuse in various ways, forming more or less complete circuits.
Stages in the development of these fusions are shown in fig. 39, plate 6,
and figs. 16 and 18, plate 5, and the completed circuits are clearly shown
in fig. 56, plate 10, which illustrates the condition in Ocyropsis wherein
there are neither tentacles nor tentacular canals to complicate the figure.

Figure 2 is a diagram intended to make clear the plan of these fusions
between the meridional and paragastric canals in the Lobate. For the
sake of clarity I have left out the auricles, which are four ribbon-like
expansions of the body on the tentacular sides of the mouth, and around
the narrow edge of each of which the meridional, subtentacular vessels
extend. The tentacles and tentacular canals are also omitted in this
diagram. Vessels on the opposite side of the animal are dotted. The
diagram shows how the two paragastric canals, g, fork at their oral ends
and form a ring-canal surrounding the mouth,m, and the four meridional
subtentacular canals fuse with this ring-canal. The four meridional sub-
ventral canals, msv, which extend along the outer sides of the oral lobes
fuse in pairs to form two loop circuits in the lobes, one loop in each lobe.
This diagram applies only to the Lobate.

In the Cestidz, on the other hand, the oral forks of the paragastric
canal of each side of the body unite with the two subtentacular and
subventral meridional vessels of that side only. Thusin this order there
is no ring-canal around the mouth. This statement applies also to the
young of the Beroide, although later the meridional vessels of both sides
become connected by anastomosing side branches which appear quite

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 5

late in ontogeny and grow outward from the sides of the 8 meridional
canals and may anastomose, thus producing a network connecting all 8
of the canals, and forming a complex circum-oral canal-system. This
remarkable similarity in respect to their canal-systems, together with
their marked compression in the funnel-axis, may, I think, be taken as
an indication that the Beroide and Cestide are related and derived
from a common stock. The condition exhibited by the fusion of the
paragastric and meridional systems of canals in the young Beroide
and in mature Cestide is shown in fig. 3, the lettering being similar in
purport to that of fig. 2.

II.

III.

!
y!
1!
1
ty
im
I
ul
tl

a=

msyv

Fic. 3.—Diagram showing character of canal system in mature Cestidz
and young Beroide. Inthe Beroide the meridional and oral canals
finally give off side branches which may anastomose, and form circum-
oral connectives, but these branches are not shown in the figure.

We may classify the Ctenophore in six orders as follows:

. Cyp1ppip#: Body spherical or cylindrical, or widest in the tentacular diameter.

Two long tentacles with or without side branches. The tentacles arise
from pit-like depressions in the sides of the body, which constitute sheaths
into which the tentacles may be withdrawn. The meridional and para-
gastric vessels do not fuse, but end blindly. No oral lobes, and no auricles.

GANESHID#: Moser, 1907, Zool. Anzeiger, Bd. 31, p. 788; also, 1908, Revue
Suisse de Zool., tome 16, p. 12.

Body compressed in the tentacular axis. The oral forks of the 2 paragastric
canals form a complete (?) ring-canal around the mouth, and the 8 merid-
ional canals join this ring-canal. The interradial and tentacular canals
arise directly from the funnel. A tentacle-sheath is present. There are
no oral lobes and no auricles. The only known form is Ganesha elegans
Moser, from the Malay Archipelago.

This remarkable order ie ce to be intermediate in its general character
between the Cydippide and Lobate, but the fusion between the merid-
ional canals and the oral forks of the paragastric vessels recalls the condi-
tion seen in Cestidz and Beroide. The Cestidz, however, lack a circum-
oral ring-canal, such as appears to exist in Ganesha.

Losat#: With 2 oral lobes in the stomodzal axis and 4 ribbon-like projec-
tions (auricles), 2 from each tentacular side of the body above the mouth.
Body compressed in the funnel (tentacular) axis. The 4 subtentacular
meridional canals fuse with the ring-canal which the oral forks of the 2
paragastric canals form around the mouth. The 4 subventral meridional
canals fuse in pairs to form loops through the oral lobes, each canal
being connected with its fellow of the opposite side of the same oral

6 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

lobe. There are numerous, simple tentacles which extend along the
wide sides of the mouth, and in the middle of each line there is usually
a principal tentacle, which is commonly feathered and arises from a large
projecting basal-bulb without a sheath. In Ocyropsis, however, there are
neither tentacles nor tentacular canals. The subventral rows of combs are
longer than the subtentacular. The larve pee through a stage in which
they resemble the Cydippide, from which the Lobate are evidently
descended. In the larva the tentacular axis is wider than the stomodzal
axis, as in Cydippide, whereas the reverse is the case in the adult Lobate.

IV. Cest1p&@: The lateral compression seen in the Lobate is greatly accentuated
in this order, so that the body is flat and ribbon-like, the long side being
in the stomodzal axis and the compression being in the funnel-axis.
There is no ring-canal around the mouth, but the subventral and sub-
tentacular vessels unite with the oral forks of the paragastric canals
and the canal-systems of the two sides are separated, uniting only at the
funnel. There is a row of tentacles along the oral forks of the paragastric
vessels. The 2 median tentacles are the largest and are set within basal
sheaths. The Cestide are closely related to Lobatez, and their larve pass.
through a cydippe-stage as do the larvee of the Lobate.

V. Breroip#: Lateral compression as in the Lobate and Cestide, the compression
of the funnel-axis being generally more marked than in the Lobate, but not
so pronounced as in the Cestide. Canal-system as in the Cestide, with the
added feature that the meridional canals and the oral forks of the para-
gastric canals give off side branches which may anastomose and form
a network connecting some or all of the vessels, in some species forming
acircumoral canal-system. The axial funnel-canal is absent and is replaced
by two side branches which extend upward from the funnel to the excretory
pores. There are no tentacles even in the larva, which in other respects.
resembles the Cydippide. The stomodeum is very wide in the sagittal
plane and constitutes a great sac, so that the funnel is very short.

VI. PLatycTenipa: Creeping or sessile, degenerate ctenophores, with the oral-
aboral axis much shortened, so that the oral and aboral sides of the
animal are flat and expanded. With 2 tentacles, which in some forms.
may be withdrawn within sheaths. The apical sense-organ may be present,
but in some forms the combs of cilia are absent. There are 3 genera,
Tjalfiella Mortensen, Coeloplana Kowalevsky and Ctenoplana Korotneff.
The species occur in the Red Sea, Malay Region, Japan, and Greenland,
and the most recent descriptions are by Willey, 1897, Quarterly Journal
Microscop. Sci., vol. 39, p. 323; Abbott, 1902, Annot. Zool. Japonensis, vol.
4, Pp. 103; and Mortensen, 1910, Vid. Meddel. Foren. Kobenhavn, p. 249.

In the extreme tenuity of their bodily substance and their diaphan-
ous delicacy of coloration, the ctenophores stand apart from other marine
animals. Their presence in the water is commonly denoted only by the
brilliant flash of rainbow colors which play along the lines of their cil-
iary combs as they move languidly beneath the unrippled surface of
the sea. Yet these creatures are no more wonderful in their complex
organization than in their remarkable adjustment to their habitat, for
so delicate are most of them that a current such as that of an oar suffices
to tear them into misshapen shreds—a fate which they escape in time of
storm by sinking far into the depths. This fact accounts for the extreme
rarity of many of these forms, for the ocean’s surface must have remained
flat as a mirror for many hours before they can be lured upward from the
calm of their deep retreat. Yet tender as they are to the touch, passing
jelly-like between the fingers of the hand that attempts to seize them,.
their food consists largely of young fishes which they engulf in great
numbers, seizing their prey by means of their peculiar ‘‘Greifzellen” (see
Chun, 1880, Ctenophoren des Golfes von Neapel, p. 225, Taf. 18). Thus
in the cold northern waters where ctenophores occur in vast swarms,

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 7

they constitute a serious menace to the cod fisheries by devouring the
pelagic eggs and young fish.

The elucidation of the minute anatomy of ctenophores has been one
of the greatest triumphs of modern histology, and one with which one
associates the names of Fol, Chun, R. Hertwig, Samassa, Grabe, and
Bethe.

Samassa was unable to demonstrate the existence of a nervous sys-
tem in Ctenophores, but Bethe, 1895 (Biol. Centralblatt, Bd. 15, p. 140),
placed living Cydippe in a solution of 1 in 4,000 of methylen blue in sea-
water, and upon sectioning the Cydippe he claims to have found a sub-
epithelial network of nervous nature. This consists of large, ganglionic
cells scattered at fairly regular intervals. Each of these cells gives rise
to 3 or 4 protoplasmic processes which fuse with like processes from other
ganglia, thus appearing to form a nervous network without separate
neurons; a condition so extraordinary that confirmatory studies must
be made before we can accept it as proven.

The experiments of Parker upon Mnemiopsis lend support to the
conclusion that nervous elements may extend outward from the apical
sense-organ along under the combs of cilia, or at any rate the normal
rhythm of the ciliary combs is controlled by the nervous or muscular
elements. I now find that in ctenophores when the muscles contract
the cilia cease to beat, being inhibited by the stretching of the ciliated
epithelium. A solution of 0.4 molecular MgCl, which inhibits mus-
cular movement and produces relaxation, causes an incessant and very
active movement of the cilia, but codrdinated movements of the rows
of combs are usually destroyed, each comb beating independently of
its neighbors and at an exceedingly rapid rate, uncontrolled by the
nervous system. In M. mccradyi, however, coérdination is retained.

From the physiological side there is evidence, but no proof, to sup-
port the view that there is in ctenophores a nervous system compara-
ble to that seen in higher metazoa. The results of such physiological
researches are stated in this paper under Nmemiopsis and Beroé.
Recently Bauer, 1910, Zeitschrift fiir Allgemeine Physiol., Jena, Bd. 10,
p. 231; concludes that the combs of ctenophores are under the control
of anervous system. He states that the nervous system can produce an
acceleration or a retardation of the movements of the combs. Weak
mechanical stimuli such as touching the mouth-region cause a stopping
of the combs, while strong stimuli cause an acceleration. The sensory
pole is without significance for this reflex. A summation of weak
stimuli produces finally the effect of a single strong stimulus, and thus
ctenophores show the well-known ‘‘treppe”’ effect which has been
observed in higher forms.

8 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

Order CYDIPPIDZ Gegenbaur, 1856.

Cydippide, GEGENBAUR, 1856, Archiv fir Naturgesch., Jahrg. 22, p. 196.—CHUN,
1880, Ctenophoren des Golfes von Neapel, pp. 30, 273, 275-—MosER, 1903,
Ctenophoren der Siboga-Expedition, p. 4.— VANHOFFEN, 1906, Nordisches
Plankton, Ctenophoren, XI, p. 2.

Pleurobrachiide, Ghigi, 1909, Ctenofori, Firenze, vol. 2, fasc, 1, p. 7-

CHARACTERS OF THE CYDIPPIDA,

Ctenophore with 2 tentacles in the funnel diameter which arise
from sheath-like clefts in the sides of the body. The body is usually
laterally compressed, the tentacular diameter being the wider, although
it may be spherical or cylindrical. There are neither oral lobes nor
auricles, The meridional and paragastric canals end blindly. The
tentacles may be simple or with side branches. The axis of the tentacle
is mesodermal as in other ctenophores.

Genus MERTENSIA Lesson, 1836.
Mertensia, Lesson, 1836, Annals des Sci. Nat., sér. x, tome 5, p. 253; 1843, Hist.
Zooph. Acal., p. 100.—Mo6rcu, 1857, Nat. Bid. til en Beskriv. af Grénland,
Bi 97.—Acassiz, A., 1865, North Amer. Acal., p. 26.—CHuN, 1898, Ergeb. der
lankton-Expedition, Ctenophoren, p. 10.—VANHOFFEN, 1906, Nordisches
Plankton, 11, Ctenophoren, p. 2.—MosEr, 1909, Ctenophoren der deutsch.
Stidpolar-Exped., Bd. 11, Zool. 3, p. 123.

GENERIC CHARACTERS.

Cydippide in which the body is laterally compressed, the tentacular
axis being wider than the axis through the plane of the stomodeum. The
4 subtentacular rows of cilia are longer than the 4 subventral rows and
arise at a higher level, and are farther removed from the apical sense-
organ than the latter. There are no wing-like protuberances upon the
sensory pole-plate.

The type species is Meriensia ovum of the Arctic Ocean. It was
first described by Fabricius, 1780, as Beroé ovum.

Mertensia ovum Lesson. (Fig. 1, plate 1.)

Beroé ovum, FaBricius, 1780, Fauna Grénlandica, p. 362, No. 355.

Cydippe ovum, C. cucullus, EscHscHoutz, 1829, Syst. der Acal., p. 25.

Beroé pileus, ScORESBY, 1820, Arct. Reg., 2, plate 16, fig. 4.

Mertensia ovum, Lesson, 1836, Annales des Sci. Nat., sér. 2, tome 5, p. 254.

Cydippe (Mertensia) ovum, M6rcH, 1857, Beskriv. af Grénland, p. 97.

Mertensia scoresbyi, Lesson, 1843, Hist. Zooph. Acal., p. 100.

Cydippe cucumis, Lesson, 1843, Hist. Zooph. Acal., p. 105.

Mertensia cucullus, Acassiz, L., 1860, Cont. Nat. Hist. U. S., vol. 3, p. 293.

Mertensia ovum, Acassiz, A., 1865, North Amer. Acalephe, p. 26, figs. 29 to 37;
1874, Mem. American Acad., vol. 10, No. 3, p. 375, figs. 1, 2. —VANHOFFEN,
1895, Bibliotheca Zoologica, Heft 20, Lig. 1, p. 21.—CHUN, 1898, Cteno-
phoren der Plankton-Expedition, p. 1o—R6MER, 1903, Fauna Arctica, Cteno-
Satin Bd. 3, p. 72 (full list of literature) —VANHOFFEN, 1906, Nordisches

lankton, x1, Ctenophoren, p. 2, figs. 1 to 3.—BicGELow, 1909, Proc. U.S. Nat.

Mus., Washington, vol. 37, p. 316.

M. ovum is larger than Pleurobrachia pileus, becoming 55 mm. long.
Body egg-shaped in outline, the mouth being at the pointed pole and the
apical sense-organ at the broad end. The body is strongly compressed
in the plane perpendicular to the tentacular radii, and thus the creature
superficially resembles a much-flattened Pleurobrachia. The apical
sense-organ contains a mass of small concretions and is surrounded bya

Fic.
Fic.

Fic.
Fic.

Leal

dS

Pw

PLATE 1.

. Mertensia ovum, immature. Agassiz Laboratory, Newport,
Rhode Island, September 7, 1895.

. Pleurobrachia brunnea sp. nov., mature. In the ocean 5 miles
off Barnegat Bay, New Jersey, October 16, 1904.

. Pleurobrachia brunnea. Side view of apical sense-organ.

. Pleurobrachia brunnea. View of one of the side branches of
the tentacles.

Drawn from life, by the author.

CTENOPHORES OF THE ATLANTIG COAST OF NORTH AMERICA PLaTE |.

ft
‘ lava °9
ee =. Oe
@ A
é cane ees
tN
7 i

Zp
Aig a
Ke

NEY

B.Meisel lith. Boston.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 9

smooth-edged polar plate, there being no wing-like protuberances, such
as are seen in Beroé. The 4 subtentacular rows of cilia are longer than
the 4 subventral rows and extend fully four-fifths the distance from the
apical plate to the oral end of the animal. The tentacles are long and
contractile and give rise to numerous short, simple, lateral branches.
The tentacles, rows of cilia, and pole-plate are light pink in color, while
the genital products are of a decided shade of the same color; the male
products being more brilliant than the female.

When very young the body is almost spherical, the oral end, how-
ever, being bluntly pointed. The rows of cilia are more fully developed
than in the young Pleurobrachia of the same age, while the tentacles
are relatively smaller and less developed and acquire their lateral branches
later. In the young Mertensia, also, there are prominent orange pigment
cells along the rows of cilia, and these are not found in Pleurobrachia.

This species is found in the Arctic Ocean. It extends southward in
winter to the New Jersey coast, becoming rarer towards the south. Young
individuals are occasionally found during the summer months in Newport
Harbor, Rhode Island, but the adults have never been taken south of Mas-
sachusetts Bay. It is sometimes seen in great numbers in the harbor of
Eastport, Maine,in September, but its true home is off the Labrador coast.
Chun, 1898, reports that large numbers of this ctenophore were observed
by the Plankton Expedition in the Labrador stream, and says that it is
identical with the Beroé octoptera described by Mertens, 1833 (Mém. Acad.
Nat. Sci. St. Pétersbourg, sér. 6, tome 2, p. 528), from Behring Sea.

Bigelow finds that Mertensia ovum from the coast of Labrador feeds
upon the sculpin.

Genus PLEUROBRACHIA Fleming, 1822.

Pleurobrachia, FLEMING, 1822, Philos. of Zool., vol. 2, Pee also, Hist. British
Animals, 1828, p. 504.—Acassiz, L., 1849, Mem. erican Acad., vol. 4, p.
314; also 1860, Cont. Nat. Hist. U.S., vol. 3, p. 203.—Acassiz, A., 1865, North
Amer. Acalephe, p. 29.—CHUN, 1880, Cucoprerd des Golfes von Neapel,
p. 281.—CHUN, 18098, pena Sea der Plankton-Expedition, p. 15.—VAN-
HOFFEN, 1906, Nordisches Plankton, Ctenophoren, p. 3.—MosER, 1903,
Ctenophoren der Siboga-Expedition, pp. 5, 30; 1909, Ctenophoren der deutsche
Stidpolar-Exped., Bd. 11, Zool. 3, ee Iq.

Cydippe, EscuscHoTz, 1829, Syst. der Acal., p. 29.—Lsson, 1843, Hist. Zooph.
Acal., p. 104.

GENERIC CHARACTERS.

Cydippide with an egg-shaped body with but little lateral compres-
sion, the tentacular diameter being only slightly wider than the sagittal.
In this respect Pleurobrachia differs markedly from Mertensia, wherein
the sagittal diameter is much narrower than the tentacular. The ten-
tacle bulbs are placed within deep clefts, midway between the sides of
the stomach and the general surface of the body. The 2 long, lateral
tentacles give rise to numerous, simple, filamentous side branches. The
8 meridional canals extend under and along the 8 rows of cilia and end
blindly, not forming a closed system of tubes.

The type species is Pleurobrachia pileus of the colder waters of the
Atlantic, being abundant off the northern coast of Europe and America.

Moser, 1903, gives a description of all of the so-called species,
and in 1909 she presents a very complete list of references to literature
and an account of the geographical range of all species.

10 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

Pleurobrachia pileus Vanhoffen.

Beroé pileus, FaBrictus, 1780, Fauna Gronlandica, p. 361, Nr. 354.

Beroé globigereux, CUVIER, 1817, Régne Animal, tome 4, p. 59.

ee pileus, GOULD, 1841, Report Invert. Mass., p. 349.—Morcu, O., 1857,

eskriv. af Grénland, p. 97.

Pleurobrachia rhododactyla, Acassiz, L., 1849, Mem. American Acad., vol. 4, part
10, p. 314, plates 1 to 5; ibid., 1860, Cont. Nat. Hist. U.S., vol. 3, pp. 203,
294; plate 2a.—Stimpson, W., 1853, Marine Invert. Grand Manan, p. 11.—
Acassiz, A., 1865, North Amer. Acal., p. 30, figs. 38 to 51; Ibid., 1874, Mem.
American Acad., vol. 10, No. 3, pp. 372 to 374, plate 3, figs. 25, 25’; plate 4,
figs. 1 to 45; plate 5, figs. 1 to 32.—FEWKES, 1884, Mem. Museum Comp.
Zool. at Harvard.College, vol. 9, No. 3, plate 9, figs. 8 to 9, 14 to 37.

Pleurobrachia rhododactyla and P. pileus, VANHOFFEN, E., 1895, Bibliotheca Zoo-
logica, Heft 20, Lfg. 1, pp. 15, 17, 21.—CURRERI, 1900, Boll. Soc. Ital. Zool.,
Roma, Anno 9g, p. 192.

Pleurobrachia pileus, Cuun, C., 1898, Ergeb. der Plankton-Expedition, Ctenophoren,
p. 15.—GRaBE, 1901, Zeit. fiir wissen. Zool., Bd. 69, p. 486, Taf. 36, 37 (develop:
ment of sexual organs).—R6MER, 1903, Fauna Arctica, Ctenophoren, Bd 3,
p. 75 (full list of literature) —MosEr, 1903, Ctenophoren der Sinedatenedt
tion, p. 5 (list of literature); also, 1908, Zool. Anzeiger, Bd. 33, p. 756.—
PARKER, 1905, Journal Experimental Zool., vol. 2, p. 409 (movements of
swimming plates, see Mnemiopsis)—BRrownkE, 1905, Bron. Royal Soc. Edin-
burgh, vol. 25, p. 784.—MosEr, 1909, Ctenophoren der deutsche Stidpolar-
Exped., Bd. 11, p. 141.—Ghigi, 1909, Ctenofori, Roy. Instituto Studi upe-
riori, Firenze, vol. 2, fasc 1, p. 9.—Evans and Ashworth, 1909, Proc. Roy.
Physical Soc., Edinburgh, vol. 17, p. 308. :

Pleurobrachia bachei, Acassiz, L., 1860, Cont. Nat. Hist. U. S., vol. 3. p. 294.—
Acassiz, A., 1865, North American Acal., p. 34.—ToRREY, 1904, Univ.
California Publications, Zool., vol. , p. 46, plate 1, fig. 3.

The body is egg-shaped, or almost spherical, and about 17 to 20
mm. in length and 14 to. 18 mm. wide in the tentacular axis. Evans and
Ashworth, 1909, record a specimen 30 mm. in length from Burntisland
Harbor, Scotland, in December. It is only slightly compressed later-
ally in the plane transverse to the tentacular diameter, so that the
lateral diameters are to each other as about 10 to 12.5, the tentacular
axis being the wider. The apical sense-capsule is situated upon the
surface and is not sunken within a niche. It incloses a small, spherical
mass of concretions and is not surrounded by protuberances, the
outer surface of the apical pole-plate being smooth. The eight rows
of ciliated plates are about equal in length each to each and extend
from points quite near the apical sense-organ, about three-quarters the
distance down the sides of the body. Each subtentacular row contains
about 38 combs of cilia, and each subventral row 35. The 2 tentacles
arise from 2 deep clefts in the sides of the body which serve as sheaths
into which the entire contractile portion of the tentacles may be with-
drawn. The tentacle-bulbs are widely separated from the sides of the
paragastric canals. When they are fully expanded the tentacles may be
15 to 20 times as long as the body and have a linear row of numerous sim-
ple, lateral filaments which give them a delicate, feathery appearence.
They are highly contractile and extremely sensitive and are constantly
changing their appearance as the animal moves through the water, at
times being drawn up into knotted, string-like masses, and at other
times being stretched far out in graceful, sweeping curves with their
lateral filaments giving them the appearance of the most exquisite one-
sided feathers. The mouth is a long, narrow slit, its wide axis being
perpendicular to the plane passing through the tentacles. The stomo-

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

Vs

"SS

‘e

Gira

7

a
V7,

>
@

Fic. 4.—Pleurobrachia pileus, from life by the author.

Halifax, Nova Scotia, September 27, rgro.
A, side view; B, looking down on oral pole. ad,adradial canals; ex,excretory pores;
f, funnel or infundibulum; ft, axial funnel tube; g, paragastric canals; 7, inter-
radial canals; m, mouth; #, pole-plate; pr, perradial canals; sto, stomodeum;

i, tentacular canals; ten, tentacles; ts, tentacle-sheaths. One tentacle is shown
in partial contraction, the other extended.

11

12 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

dzum also is wide and flat and is between one-half and one-third as long
as the long axis of the ctenophore. The funnel-cavity, or mid-region of
the central entodermal part of the gastric system, sends out 2 wide
paragastric branches, and also 2 canals to the bases of the tentacles, and
it also gives rise to 4 interradial side branches, each one of which
bifurcates, thus giving a canal to each of the 8 rows of ciliated plates.
The gelatinous substance is transparent and glassy, while the tentacles
and stomodeum are milky, or dull orange yellow or brownish orange.

Fic. 5.—Pleurobrachia pileus; view looking down upon apical sense-organ
at aboral pole of the animal.

Lettering as in fig. 4. e, ova in meridional canals under ciliary combs; s, sensory
tracts from apical sense-organ to rows of combs; to, opening of tentacle-sheath.

The development has been studied by A. Agassiz, 1865, 1874. In
common with that of other ctenophore, it is a simple metamorphosis.
When young the tentacular diameter is about twice as great as the sagit-
tal and the body is thus compressed laterally as in Mertensia. The combs
of cilia make their appearance as 4 double rows of simple, hair-like lashes;

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 13

later these rows separate, forming 8 rows, 45° apart. The tentacles
make their appearance very early in development, indeed almost as
early as the combs of cilia. At first the tentacles are mere knob-like
protuberances, but they rapidly elongate into simple, slender threads,
and later the lateral branches make their appearance. These lateral
branches begin to develop near the proximal end of the tentacle. At
first the tentacle bulb arises from the outer surface of the side of the
body, but later it becomes overgrown, so that finally it comes to lie at
the bottom of a deep sheath-like cleft. The body of the young Pleuro-
brachia becomes pear-shaped and elongated, the polar axis being about
1.5 times as long as the tentacular axis. Later these axes come to be
almost equal, each to each, and the body is nearly spherical. The pro-
cess of development of the central part of the gastro-vascular system
is similar to that in Mnemiopsis. The young Pleurobrachia remains
within the egg envelope until it has become pear-shaped and has 2 long,
simple tentacles. While within the egg it swims about and rotates upon
its axis, very much as does the adult animal in the water. When float-
ing passively in calm water the adult ctenophore remains with its mouth
upward. When it swims it progresses with the mouth forward.

This species is an inhabitant of the Arctic, and according to Moser,
1908, 1909, also of the Antarctic and Pacific oceans. It extends south-
ward in Europe into the North Sea, and in America along the coast of
New England as far as Cape Cod, although winter storms drive it far
southward along our coast. It is recorded from the Bermudas, but
here I think the young of Bolinopsis vitrea has been mistaken for
Pleurobrachta. Early in April it is found on the southern coast of New
England (Newport Harbor), but as the water becomes warmer with the
advance of spring it disappears and is not seen through the summer
months. In the cold waters of the coast of Nova Scotia, or Maine, it
frequently forms vast swarms during the summer, and at times these
ctenophore almost touch one another over wide areas. In common with
other ctenophore it approaches the surface most readily on calm days
and a moderate ripple is usually sufficient to cause it to sink. This
species appears, however, to be not so sensitive to disturbance of the
water as are the larger forms, such as Muemiopsis and Bolinopsis. On
the Pacific coast of North America this ctenophore has commonly been
called Pleurobrachia bachet. According to Moser it is found off New
Zealand and in the South Seas, but she studied only preserved material,
an almost hopeless task with ctenophores. I have never seen it at
Tortugas, Florida.

Curreri, 1900, records it from Messina, Mediterranean, stating that
he found it there in great numbers in April, 1897; it seems possible,
however, that he may have seen the young of Bolinopsis, which closely
resembles the adult of Pleurobrachia.

In the so-called genus Cydippe, which is probably identical with
Pleurobrachia, Bethe, 1895 (Biol. Centralblatt, Bd. 15, p. 140), believes
that he has demonstrated by means of methylen blue that there is a sub-
epithelial nerve-plexus, the ganglion cells being multipolar, each with
3 0r 4 protoplasmic processes

9

14 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

Grabe, 1901, finds that in Pleurobrachia pileus the anlagen of the
sexual cells are found, not only in the 8 meridional canals, but also in the
paragastric and tentacular vessels. The sex-cells are apparently of ecto-
dermal origin, as R. Hertwig, 1880, found them to be in other ctenophores.

L. Agassiz, 1849, gives beautiful figures of P. pileus.

Pleurobrachia brunnea sp. nov. (Figs. 2 to 4, plate 1.)

This species may be at once distinguished from the more northerly
Pleurobrachia pileus by its more oblong, egg-shaped body, and especially
by the opaque yellow-brown color of the stomodzeum and the terminal
knobs of its tentacles.

The body is egg-shaped with but little lateral compression and is
1zmm.long. The 8 ciliated tracts are of equal lengths and extend over
the middle two-thirds of the sides of the body. The 8 meridional canals
extend downward a considerable distance beyond the combs of cilia
and end blindly without anastomosing. The 2 tentacles arise from deep
clefts which open to the exterior at the middle of the aboral half of the
sides of the body. Each tentacle gives rise to about 32 simple side
branches, which often coil into helices and are highly contractile. The
main shaft of each tentacle terminates in a large, knob-shaped end. A
row of deep purple pigment spots extends half-way down each tentacle
shaft on the abaxial side, and the side branches of the proximal halves
of the tentacles are also dotted over with these purple spots. The ten-
tacles differ markedly from those of Pleurobrachia pileus in their fewer
side branches and in the fact that they end each in a large knob.

This species was found by the author in large swarms off the coast
of New Jersey, from Sandy Hook to Barnegat Bay, on October 16, 1904.
It is separated from Hormiphora plumosa by the greater length of its
meridional vessels, which extend a considerable distance beyond the oral
ends of the rows of combs instead of ending with the combs, as in H.
plumosa, The bases of the tentacles are not closely applied to the sides
of the paragastric vessels as in Hormiphora, but are widely separated.
Moreover, in H. plumosa the lower (oral) ends of the tentacle-sheaths
are slightly below the ends of the meridional canals, whereas in P. brunnea
the meridional canals extend below the ends of the tentacle-sheaths.

P. brunnea bears a closer resemblance to Hormiphora spatulata Chun,
from the Canary Islands and the Straits of Gibraltar, but its ciliated
combs begin at a greater distance from the apex than in H. spatulata,
and the tentacles of P. brunnea terminate in knob-like ends instead of
tapering to points. H. spatulata is described by Chun, 1898, Ctenophoren
der Plankton Expedition, p. 18, Taf. 2, 3.

Genus HORMIPHORA L. Agassiz, 1860.

Cydippe, GEGENBAUR, 1856, Archiv fiir Naturgesch., Jahrg. 22, p. 200.—Sars, M.,

1856, Middelh. Litt. Fauna, p. 71.—PANcERI, 1872, Atti Acad. Napoli, vol.
, Pp. 2.

Howe phon, Acassiz, L., 1860, Cont. Nat. Hist. U. S., vol. 3, p. 196.—CHUN,.
1880, Ctenophoren des Golfes von Neapel, p. 280; also, 1898, Ctenophoren
der Plankton-Expedition, p. 16.—MoseEr, 190%, Ctenophoren der Siboga-
Expedition, pp. 9, 31; 1908, Abhandl. Akad. Mtinchen, Supplement Band 1,
Abhandl. 4, p. 10; 1909, Ctenophoren der deutsche Siidpolar-Expedition,

Bd. 11, Zool. 3, p. 148.

Fic.

Fic.

Fic.
Fic.

PLATE 2.

5. Hormiphora plumosa. Specimen from Tortugas, Florida,
May 20, 1906.

6. Surface view of apical pole-plate showing lithocyst. ex,
excretory pores; #, sensory tracts from sense-organs to
tows of combs; ts, openings of tentacle sheaths.

7. Side view of apical sense-organ.

8. View of tentacle. 8a. Enlarged view of appendages on base
of tentacle.

Drawn from life, by the author.

PLATE 2.

GTENOPHORES OF THE ATLANTIG CCAST OF NORTH AMERICA

B.Meisel lith. Boston

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 15

GENERIC CHARACTERS.

Body oval or egg-shaped, sagittal diameter almost as great as the
tentacular axis. The animal resembles Pleurobrachia except that the
tentacles usually bear two or more kinds of side branches instead of
simple filaments. Also in Hormiphora the tentacle bases arise from the
bottom of deep clefts close to the sides of the paragastric vessels while
in Pleurobrachia the clefts are not so deep and the tentacle bases are
situated at points about half-way between the sides of the paragastric
vessels and the outer surface of the body.

The type species is Hormiphora plumosa of the Mediterranean.

This genus is so closely allied to Pleurobrachia that I consider its
separation to have been unfortunate and future discoveries of forms will,
I believe, reveal intergrades and oblige us to unite the two genera under
the older name Pleurobrachia.

Moser, 1903, gives a diagnosis of all of the species of Hormiphora
known at that time, and in 1909 she gives a list of species with their
geographical ranges.

Hormiphora plumosa L. Agassiz. (Figs. 5 to 8a, plate 2.)
Cydippe hormiphora, GEGENBAUR, 1856, Archiv ftir Naturgesch., p. 200, Taf. 8

g. Io.

Cydippe plumosa, Sars, M., 1856, Middelhavets Litt. Fauna, p. 71.

Hormiphora plumosa, Acassiz, L., 1860, Cont. Nat. Hist. U. S., vol. 3, p. 196.—
Cuun, 1880, Fauna and Flora des Golfes von Neapel, Monographie 1, pp. 64,
281, Taf. 1, Fign. 5, 6; Taf. 2, Fign. 2, 3; Taf. 3, Fign. 8, 9 —MaveEr, 1900,
Bull. Mus. Comp. Zool. at Harvard College, vol. 37, p. 82.—MosER, 10903,
Ctenophoren der Siboga-Expedition, p. 10.—Samassa, 1892, Archiv Mikro-
skop. Anatomie, Bd. 40, pp. 173, 223 (histology).—Ghigi, 1909, Ctenofori,
Firenzi, vol. 2, p. 14.

Cydippe densa, SPAGNOLINI, 1870, Cat. Ber. Golfo. d. Napoli, Bull. d. Nat. e Med.
Napoli, p. 61.

This Mediterranean species is occasionally found near the surface
upon calm days in summer at the Tortugas, Florida, and thus it is ap-
parently distributed from the Mediterranean across the tropical Atlantic.

The body is about 15 to 20 mm. long, oval, with bluntly rounded
aboral pole and more or less narrowed oral pole, giving an egg-shaped
outline. The shape of the body changes, however, with the states of
contraction of the animal and may vary considerably in ratio of width
to length. There is practically no lateral compression, the cross-section
of the body being very nearly circular. The apical sense-organ is simple
and not appreciably sunken beneath the surface, and the apical pole-
plate bears no protuberances. There are 2 excretory pores. The 8
meridional rows of ciliated combs are all equal each to each in length.
They begin at a considerable distance below the apical sense-organ and
extend to the lower third of the body. The 8 meridional vessels do not
extend far below the lower ends of the rows of combs. There are
about 25 to 4o combs in each row. Of the chymiferous vessels, the
2 perradial are extremely short, the 4 interradial quite long, and the 8
adradial about as long as the interradial. The funnel-tube is well devel-
oped and tapers so as to be narrowest near the apical sense-organ. The
stomodeum and 2 lateral paragastric tubes are simple and narrow. The

16 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

inner end of the stomodeum contains dull-yellow and reddish-brown
pigment. The 2 tentacle-bases are closely pressed to the sides of the
paragastric canals. Their lower ends are simple, not hooked, and extend
slightly below the level of the lower ends of the 8 meridional vessels.
The tentacle-sheaths are voluminous and long, and taper upward so
as to open to the outside slightly below the level of the aboral ends
of the rows of combs. The tentacles bear a pair of cock’s-comb-shaped
expansions upon the upper sides of their bases. They also give rise to
numerous, simple, filamentous side branches and a few more or less
hand-shaped appendages at very irregular intervals. The side branches
of the tentacles are slightly yellow. The canal-system and other parts of
the entoderm of the animal are slightly milky, other parts being trans-
parent.

This ctenophore is not common either in the Mediterranean or at
Tortugas, Florida. It is beautifully figured by Chun, 1880, in his Naples
Monograph of the Mediterranean Ctenophore.

Genus TINERFE Chun, sens. ampl.

Ute, CHUN, 1889, Sitzungsber. Akad. Wissen., Berlin, Jahrg., 1889, p. 525.

Ute, preoccupied by Schmidt for Sponges.

Tinerfe, CHUN, 1898, Ergeb. der Plankton-Exped., p. 6.— Moser, 1909, Cteno-
phoren der deutsche etdpalarBapedition, Bd. 11, Zool. 3, p. 131.

Chun defines this genus of the Cydippide as follows:

Body cylindrical, only slightly compressed in the stomodeal plane.
Two kidney-shaped, gelatinous protuberances project above the apical
sense-organ in the funnel-plane. Paragastric vessels well developed.
‘Tentacle-bases long. Genital products developed only in the 4 subten-
tacular meridional vessels.

The generic designation cited above applies to two small Ctenophore
from Tortugas, Florida, with the exception that the gelatinous swellings
flanking the sense-organ are mammiform in one and papilliform in the
other species, not kidney-shaped, and the genital products are developed
in all of the 8 meridional vessels. Also the tentacle bases of one species
are short, not long. We might profitably amplify Chun’s definition of
the genus and avoid stating the precise shape of the protuberances on the
sides of the apical sense-organ, and omit the restriction that the genital
products develop in only 4 of the meridional vessels, for this is probably
only an indication of immaturity; or that the tentacle-bulbs be either
long or short.

We would thus amplify Chun’s definition to read as follows: Cydip-
pide with nearly cylindrical body, only slightly compressed in the stomo-
deal-axis. With protuberances in the funnel-plane on both sides of the
apical sense-organ. Paragastric canals well developed. Tentacles sunken
within sheaths in the funnel axis. Tentacles with lateral filaments.

Chun’s Tinerfe cyanea from the Canary Islands is the smallest cteno-
phore known, being only 2 to 2.5 mm. long when mature, The Tortugas
forms, Tinerfe lactea and T. beehleri, are also very small, being only
g mm. long. The type species is Timerfe cyanea Chun.

PLATE 3.

Fic. 9. Tinerje lactea sp. nov. Tortugas, Florida, July 3, 1906.

Fic. 10. Tinerfe beehleri sp. nov. Tortugas, Florida, May 9, 1906.
Body-walls contracted so as to form 8 temporary mounds
above sense-organ.

Fic. 11. Tinerfe beehleri. Sense-organ seen from side, body normally
expanded so that there are no mounds around sense-organ.

Drawn from life, by the author.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA PLATE 3

B.Meisel lth. Boston.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 17

Tinerfe lactea sp. nov. (Fig. 9, plate 3.)

Body oval, 9 mm. long, 5 mm. wide in the funnel-plane, and 3 mm.
wide in the stomach-plane. The apical sense-capsule is raised above the
general body-surface and is covered with bristles. It is flanked on both
sides in the tentacular-diameter by 2 prominently projecting, mammi-
form, gelatinous papillae. The 8 rows of combs are of equal length and
extend from very near the apical sense-organ to the middle of the sides
of the body. Each row consists of about 25 combs. The 8 meridional
canals extend beyond the lower ends of the rows of combs and taper to
simple, pointed ends near the mouth, the 4 subtentacular vessels being
slightly longer than the 4 subventral. All of these canals widen laterally
below the lower ends of the rows of combs, and their lower ends are filled
with genital products. The funnel-tube is wide and flat, and lyre-shaped
in outline. The stomodeum is well developed and there are 2 narrow,
lateral, paragastric canals in the tentacular diameter. The tentacle
bases are long and pressed closely against the sides of the paragastric
canals. The wide tentacle-sheaths proceed straight outward, opening
at the middle points of the sides of the body. The 2 long, tapering ten-
tacles have each a few simple, filamentous side-branches.

When mature the eggs are cast out through the side walls of the 8
meridional canals. The animal is very active. The body is milky and
translucent. It is a rare ctenophore and I have seen only 3 specimens,
all found in July, near the surface, about 4 miles from land off Tortugas
Islands, Florida.

Tinerfe beehleri sp. nov. (Figs. ro and 11, plate 3.)

Named in honor of Commodore William H. Beehler, U. S. N.,
formerly commandant at Key West; for many years the most constant,
kindly, and powerful friend of the Tortugas Laboratory of the Carnegie
Institution of Washington.

Body nearly cylindrical, 9 mm. long and 4.2 mm. wide, with only
slight compression in the stomodeal-axis. It is difficult to determine
the amount of this compression, however, for the shape of the animal
almost constantly changes through vermiform contractions of the body-
wall. Indeed, these movements seem to aid in some measure in enabling
the creature to swim. At times the aboral pole is evenly rounded and
dome-like, while at others contractions cause 8 mounds to project above
the apical sense-organ, as is shown in fig. 10, plate 3. The sense-capsule
is simple and not sunken within a furrow, but on both sides of it in the
funnel-axis there are papilliform swellings. The 8 rows of ciliary combs
are less than half as long as the body and are all of equal length. Each
row consists of about 15 combs. They are widely separated from the
apical sense-organ.

The stomodeum is well developed and laterally flattened. The
funnel is large, but the axial funnel-tube is very short and is cleft for
about half its length by the basal part of the sensory cushion of the
lithocyst-plate. The interradial and adradial canals extend from the
aboral ends of the rows of cilia to near the level of the mouth. These

18 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

meridional vessels are wide and their edges exhibit a wavy outline, prob-
ably due to contraction. The 2 paragastric vessels are well developed and
closely pressed to the sides of the stomodeum. They flare outward at
the level of the mouth. The 2 tentacular canals are very short and the
tentacle bases small, but the sheaths are correspondingly long and extend
downward and finally outward, to open very near the mouth at about
the level of the oral ends of the meridional canals. I have never seen
the tentacles protrude beyond the sheaths, but they appear to have
lateral filaments.

I have not seen the genital products and can not state that the
specimens were mature, for the dull milky color of this animal renders
it only about as translucent as ground glass, so that minute details of
its internal structure can be seen only with difficulty. It is rare and I
have seen only 4 specimens between May and July at Tortugas, Florida.
It comes to the surface only when the water has been calm and unrippled
for some hours.

Order LOBAT L. Agassiz, 1860.

Beroide lobate, EscuscuHoutz, 1825, Isis, p. 741.

Mnemiide, EscuscHourz, 1829, Syst. der Acal., p. 29.

Callianiride, MERTENS, 1833, Mém. Acad. St. Pétersbourg, sér. 6, tome 2, p- 495.

Calymmide, GEGENBAUR, 1856, Archiv fiir Naturges., Jahrg. 22, Pp. 192.

Lobate, Acassiz, L., 1860, Cont. Nat. Hist. U. S., vol. 3, pp. 199, 289.—AGassiz,
A., 1865, North Amer. Acal., p. 14.—CuuN, 1880, Ctenophoren Golfes von
Neapel, p. 287, 1898, Ctenophoren der Plankton-Expedition, p. 22.—Van-
HOFFEN, 1906, Nordisches Plankton, Ctenophoren, p. 4.—MosEr, 1903, Cteno-
eborsn der Plankton-Expedition, p. 16; also, 1908, Abhandl. Akad. Mtinchen,

uppl. Bd. 1, Abhandl. 4, p. 36; also 1, 1909, Ctenophoren der deutsche Stid-

polar-Exped., Bd. 11, Zool. 3, p. 161.
CHARACTERS OF THE LOBATA.

The body is laterally compressed, the gastric axis through the stomo-
dzum and oral lobes being longer than the funnel-axis through the lateral
tentacles. There are 2 oral lobes, 1 on each side of the mouth. At the
lower ends of each of the subtentacular combs of cilia there are 4 freely
projecting, ribbon-like auricles which are fringed along their narrow
edges with cilia. The 4 principal, interradial, entodermal canals spring
directly from the funnel. The meridional canal-system communicates
with the |-shaped oral ends of the 2 paragastric tubes and also winds
in a more or less complex manner in the substance of the oral lobes.
The tentacle bases are near the oral pole. There are no tentacle-sheaths.

The larva passes through a Mertensia-like stage, and in Leucothea
the animal may become sexually mature while in this condition.

It is evident that the Lobatz are derived from the Cydippide and
that they came from Mertensia-like ancestors.

It is interesting also to see that the Cestide are closely related to
the Lobate, and the canal-systems of the Cestide and Beroide are some-
what similar each to each in their general features.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 19

Genus LESUEURIA Milne-Edwards, 1841.

Lesueuria, MitNE-Epwarps, H., 1841, Annal. des Sci. Nat., sér. 2, tome 66, p.
199.—LEsson, 1843, Hist. Zooph. Acal., p. 90.—Acassiz, L., 1860, Cont. Nat.
Hist. U. S., vol. 3, p. 290.—Acassiz, A., 1865, North Amer. Acal., p. 23.—
Cuun, 1880, Ctenophoren des Golfes von Neapel, pp. 290, 291.—VANHOFFEN,
1906, Nordisches Plankton, Ctenophoren, p. 4.—Moser, 1908, Abhandl.
Akad, Munchen, Suppl. Bd. 1, Abhandl. 4.

GENERIC CHARACTERS.

Lobate with rudimentary oral lappets and with long, ribbon-shaped
auricles. The peripheral gastro-vascular system is simple, without
complex windings.

The type species is Lesueuria vitrea of the Mediterranean.

The so called American species L. hyboptera is said to be more nearly
rectangular in outline than the oval-shaped L. uitrea of Europe. In the
American form the body is wider both above and below than it is in the
‘middle, thus giving it somewhat the appearance of a laterally flattened
hour-glass.

Lesueuria hyboptera A. Agassiz.

Lesueuria hyboptera, Acassiz, A., 1865, North Amer. Acalephe, p. 23, figs. 25-28.—

VANHOFFEN, 1895, Bibliotheca Zoologica, Heft 20, Lfg. 1, p. 18.

The body of the adult animal is 100 mm. long, while the broad side
(stomodzal axis) is 50 mm. and the narrow side (funnel-axis) is 30 mm.
‘The lateral compression is thus almost as great as in Mertensia, but of
reverse character, the gastric axis of Mertensia being the narrower.
The body is widest at about the level of the mouth. The apical sense-
-organ lies at the bottom of a narrow cleft about 12 mm. in depth. The
4 subtentacular rows of ciliated combs are each about half as long as the

‘body and terminate near the bases of the 4 auricles. These auricles are
very large, being almost 50 mm. in length. They are wide and ribbon-
. shaped and their free edges are lined with a row of hair-like cilia. The
_4 subventral rows of ciliated combs are longer than the 4 subtentacular
‘rows and extend over fully three-fourths of the length of the body. The
2 oral lappets are short and blunt, being not more than one-tenth as
long as the body of the animal. This bluntness imparts an almost rec-
‘tangular appearance to the creature when seen from the broad side.
The stomodeum is long and narrow, while the funnel-tube is very short.
~The tubes of the peripheral canal-system are extremely narrow and
-exhibit no complex windings. The 4 subtentacular meridional vessels
wind somewhat as they enter the auricles, while the 4 subventral merid-
‘ional tubes are quite straight and do not wind as they extend through
the substance of the oral lappets. The animal is almost transparent,
‘being of a slightly milky hue. It gives rise to an intense steel-blue
-phosphorescence when disturbed at night.
This species must be a very rare and occasional visitor to our
-coast. A. Agassiz found it in great numbers in Massachusetts Bay and
Newport Harbor about 1860, but it has never been seen since that time.
It is interesting to notice that M’Intosh, 1888 (Ann. and Mag. Nat. Hist.,
ser. 6, vol. 2), reports the sudden appearance of great swarms of a species
of Lesueuria, possibly Bolinopsis ?, off the coast of Scotland. The fore-
_going description is derived entirely from A. Agassiz, who is the only

20 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

observer of the American Lesueuria, and I am beginning to suspect that
this so-called Lesueuria is only a Bolinopsis infundibulum with its oral
lobes torn off and the edges healed over to produce a rounded contour,
for I found many specimens of this ctenophore in Halifax Harbor in
such condition after a storm in September.

Genus BOLINOPSIS L. Agassiz. (sens. emend.)

Bolina, preoccupied by RaFINESQUE for mollusca in 1815.

Bolina, MERTENS, 1833, Mém. Acad. Sci. St. Pétersbourg, Sci. Math. et Nat., sér. 6,
tome 2, p. 513.—Acassiz, L., 1849, Mem. Amer. Acad., vol. 4, p. 349; also,
1860, Cont. Nat. Hist. U. S., vol. 3, p. 249.—PaTTERSON, 1839, Trans. Roy.
Trish Acad., vol. 19, p. 154.—Acassiz, A., 1865, North Amer. Acal., p. 14.—
CuuNn, 1880, Ctenophoren Golfes von Neapel, pp. 290, 292.—von LENDEN-
FELD, 1885, Proc. Linnean Soc. New South Wales, vol. 9, part 4, p. 929.—
Cuun, 1898, Ctenophoren der Plankton-Expedition, p. 22—MosEr, 1908,
Abhandl. Akad. Mtinchen, Suppl. Bd. 1, Abhandl. 4, p. 47.

Springbrunner-Rotzfisch, MARTENS, 1675, Spitzbergische Reisebeschr., p. 131.

Beroé, Mttuer, O. F., 1776, Zool. Danica, Prodromus, Nr. 2816, p. 232.

Mnemia, Sars, M., 1835, Beskriv. og Jagttagelser, p. 23.

Bolina, Alcinoe, Anais, Lesson, 1843, Hist. Zooph. Acal., pp. 83, 89, ror.

Anais, preoccupied for Aves by Lesson, 1840.

Bolinopsis, Acassiz, L., 1860, Cont. Nat. Hist. U.S., vol. 3, p. 290.
Unfortunately, the old and familiar generic name Bolina is pre-

occupied, having been used in 1815 for mollusca by Rafinesque. Alcinoé

of Rang, 1828, and Mnemia of Eschscholtz, 1829, apply to a ctenophore
which is certainly not a Bolina but is closely allied to if not identical with

Mnemiopsis. Lesson’s Anais, 1843, was preoccupied by himself in 1840

for birds, and Hapalia of Eschscholtz, 1825, is founded upon an imper-

fect specimen which may possibly be a Bolina, but even so the name

Hapalia is preoccupied for Lepidoptera by Htbner in 1816.

Bolinopsts of L. Agassiz, 1860, is the only one of these names which
can be applied to the genus. Agassiz instituted this name to apply to
the Bolina elegans of Mertens, 1833, and he separated it from Bolina on
account of the numerous, small papilla which are found upon all parts
of the outer surface of the body, except the lower parts of the oral lobes.
We may, however, consider this to be a specific rather than a generic
character, especially as by so doing we will not confuse this genus with
Leucothea (Eucharis), wherein the papille are much larger and cover the
whole of the outer parts of the oral lobes. Moreover, the lateral pits in
the tentacular axis, so well developed in Leucothea, are not found in
Bolinopsis. Thus by broadening the definition of Bolina we may retain
it under the somewhat similar name Bolinopsis. I prefer to do this
rather than to institute a new and wholly unfamiliar name.

GENERIC CHARACTERS.

Lobate in which the 2 oral lobes are of medium size and not provided
with powerful muscles as in Ocyropsis. The 4 relatively short, simple
auricles arise from the sides of the body immediately above the mouth
and close to the sides of the oral lobes. They are not set within deep
grooves as in Mnemiopsis. The peripheral chymiferous tubes form
closed circuits in the oral lobes and do not end blindly as in Deiopea.
The auricles are shorter and the oral lobes much longer than in Lesueuria.
The combs of cilia are small and numerous.

The type species is Bolinopsis infundibulum of the Arctic and cold

temperate regions.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 21

This genus is closely related to Mnemiopsis, for Mnemiopsis in its
growth passes through a Bolinopsis stage. Phylogenetically speaking
Bolinopsis is simply an arrested form of Munemiopsis, or Mnemiopsis an
advanced condition of Bolinopsts.

Bolinopsis infundibulum. (Figs. 12 to 15, plate 4.)

Springbrunner-Rotzfisch, MARTENS, 1675, Spitzbergische oder Gronlandische Reise-
besch., p. 121, Taf. P.

Beroé ovata, BastER, 1762, Opscula subsecina, Bd. 1, p. 124, Tat. 14, fig. 5.

Volvox beroé, LINN&US, 1768, Systema Nature, ed. 12, Part 4, Corals, p. gro.

Beroé infundibulum, Mtuter, O. F., 1776, Zoologice Danice, Prodromus, p. 232,
Nr. 2816.—Fasricius, O., 1780, Fauna Groénlandica, p. 360, No. 352.

Bolina infundibulum, Cuun, 1880, Ctenophoren des Golfes von Neapel, pp. 293,
294.—R6MER, 1903, Fauna Arctica, Bd. 3, Ctenophoren, p. 78 (full list of
literature).—VANHOFFEN, 1906, Nordisches Plankton, Ctenophoren, p. 5,
fig. 11.—BRowngE, 1905, Proc. Royal Soc. Edinburgh, vol. 25, p. 784.—Evans
and Ashworth, 1909, Proc. Roy. Physical Soc. Edinburgh, vol. 17, p. 309, fig.

Bolina norvegica, Voct UND YuNG, 1888, Lehrbuch der Vergleich. Anatomie, Bd.
I, p. 170, Fign. 71-85.

Bolina septentrionalis, MERTENS, 1833, Mém. Acad. des Sci., St. Pétersbourg, Sci.
Math. Phys. et Nat., sér. 6, tome 2, p. 515, Taf. 7, fign. 1-5.

Bolina alata, Acassiz, L., 1849, Mem. American Acad., vol. 4, part 2, p. 349,
plates 6-8; also, 1860, Cont. Nat. Hist. U. S., vol. 3, pp. 249, 289.—STIMPSON,
1853, Marine Invert. Grand Manan, p. 11.—PAcCKARD, 1863, List of Animals
dredged near Caribou Isd., Canadian Naturalist and Geologist, vol. 8—Acassiz,
L., 1865, North American Acal., p. 15, figs. 1-18.—Acassiz, A., 1874, Mem.
American Acad. Arts Sci., vol. 10, No. 3, p. 376, figs. 3-12.—VANHOFFEN,
1895, Bibliotheca Zoologica, Heft 20, Lfg. 1, p. 1y.

Alcynoé vermicularis, GouLD, 1841 (non Rang); Nevere of Mass., p. 349.

The adult (fig. 14, plate 4) ‘s about 110 to 150 mm. long. The
aboral end is bluntly pointed and subconical, while the oral lobes are
large and rounded. Thus the general outline of the body is pear-shaped,
although the creature is compressed laterally. The lobes are about one-
third as long as the body of the animal. The apical sense-organ is placed
at the bottom of a deep, narrow cleft. It is very minute and contains
a mass of small, white concretions. The 4 subtentacular rows of combs
arise from the summit of the conical, aboral end of the animal and extend
straight down to the bases of the 4 auricles, which arise from the sides
of the animal at points about one-third the distance from mouth to apical
sense-organ. The subtentacular rows contain each about 35 to 4o
combs, while the auricles are edged with a linear row of ciliary combs.
The auricles are flat and ribbon-like and about one-quarter as long as the
ent re animal. The 4 subventral combs of cilia arise from the base of
the conical, aboral end of the animal and extend straight down to points
near the free, outer ends of the oral lobes. Each of these rows consists
of about 50 combs which extend about two-thirds the entire length of
the animal and reach a level lower than that of the ends of the 4 sub-
tentacular rows. The oral lobes are wide, rounded, and flexible and are
commonly folded so as to overlap on both sides of the mouth. Their
inner sides are provided with delicate longitudinal and transverse mus-
cles, the contractions of which enable the animal to compress the lobes
with considerable force, although not with sufficient rapidity to be of
any appreciable service in swimming, this being accomplished almost
exclusively through the movements of the combs of cilia. There is a

22 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

row of small, thread-like, simple tentacles on both of the wide sides of
the mouth. The median tentacles, one on each side in the axial plane,
are longer than the others and are provided with simple, lateral fila-
ments. These are the primary tentacles of the larva which still persist
in the adult. The stomodeum is long and narrow, and the mouth is
a long cleft, perpendicular to the tentacular diameter. The funnel is
very short, being only about one-seventh as long as the stomodzeum.
The peripheral tubes of the gastro-vascular system are of small caliber.
The meridional ventral tubes give rise to very complex and variable
windings in the oral lobes. The entire animal is almost transparent,
but when mature is slightly milky in hue.

The development has been studied by A. Agassiz. The general
appearance of the very young animal is quite similar to that of the
young Pleurobrachia or Mertensia. The 2 tentacles of the young larva
are long and flexible and are provided with numerous, simple lateral
filaments, as in Mertensia. The stomodeum and the chymiferous tubes
are more slender in the young Bolinopsis than they are in Pleurobrachia.
As development proceeds, the general outline of the body becomes egg-
shaped, the aboral pole being blunt, and the tentacular diameter com-
pressed. The oral lobes appear quite late on both sides of the mouth
and still later the auricles begin to develop at the inner angles of the
bases of the lobes. At the same time the bases of the 2 tentacles begin
to migrate downward toward the sides of the mouth, carrying their
chymiferous tubes down with them. The meridional tubes are at first
simple and blindly ending as in Mertensia, and lie immediately under
the combs of cilia; but when the oral lobes begin to develop they extend
downward and finally form closed loops by the fusion of their free ends.
Thus the meridional ventral tubes of adjacent sides are joined through
complex windings in the oral lobes; while the meridional tentacular
tubes extend outward through the auricles and downward around the
free lower borders of the oral lobes. They also join with the oral forks
of the lower ends of the paragastric canals, thus forming a closed circuit
around the mouth. The details of the development are fully described
and illustrated by A. Agassiz, 1865, 1874.

This is one of the commonest ctenophores along the New England
coast north of Cape Cod. It is not found on the southern coast of New
England, but is exceedingly abundant off the coast of Newfoundland, or
northern Maine in summer. It also occurs throughout the Arctic regions
and off the coasts of Norway and Scotland, and southward to the shores
of Northern Germany. I believe that Bolina septentrionalis of Mertens,
1833, is this same ctenophore from Behring Sea.

Romer, 1903 (Fauna Arctica, p. 80), gives a detailed account of its
distribution and a long list of its synonyms.

Bolinopsis vitrea. (Figs. 16 to 19, plate 5.)

Bolina vitrea, Acassiz, L. 1860, Cont. Nat. Hist. U. S., vol. 3, pp. 250, 269, 289,
fig. 93.—Acassiz, A., 1865, North Amer. Acalephe, p. 19, fig. 19 —Cuun,
1898, Ctenophoren der Plankton-Expedition, p. 22—MAYER, 1900, Bull.
Museum Comp. Zool. at Harvard College, vol. 37, p. 81, figs. 91, 92, plate 27.

Bolina hydatina, Chan, 1880, Ctenophoren des Golfes von Neapel, p. 292, Taf. 4,

fign. 5, 6.

Fic.

Fic.

Fic.

Fic.

PLATE 4.
Bolinopsis infundibulum.

12. Side view of half-grown specimen, twice natural size. East-
port, Maine, August 20, 1897.

13. Side view of half-grown specimen, twice natural size, show-
ing winding course of meridional ventral vessels in oral
lobes. Eastport, Maine, August 23, 1897.

14. Side view of full-grown specimen, natural size. Eastport,
Maine, September 22, 1898.

15. Sense-organ of ctenophore shown in figure 14.

Drawn from life, by the author.

CTENOPHORES OF THE ATLANTIC Coast oF NORTH AMERICA PLATE 4

hee per err

B.Meisel lith. Boston.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 23

In the adult the body is oval, bluntly pointed above, and there is
considerable lateral compression, the tentacular diameter being only a
little more than one-half as wide as the transverse. The creature is
about 80 mm.long. The aboral apex is quite blunt and the oral lobes
are wide and about three-quarters as long as the remaining portion of

Table showing the dimensions in mm. of specimens of B. vitrea from Tortugas, Florida,
taken in June, 1910.

Speci- Speci- Speci- Speci- Speci- Speci-

men A, | men B. | menC, | men D. | men E, | men F,
Total length of body............6.- 80 60 61 63 60 59
Length from aboral apex to mouth... 58 49 40 43 36 39
Maximum width in average expansion

of the stomodzal axis ............ 46 39 oa 45 44 40

Width of body in tentacular axis .... 23 22 22 24 ai 23
Width across expanded lobes........ 38 45 52 39 40 38
Length of auricles.............00055 20 19 16 16 15 15.5
Depth of cleft of sense-organ....... 9 9 5 1 5.5 8
Length of short rows of combs...... 37 28 23 28 at 27
Length of long rows of combs....... 73 57 5I 47 4r 48
Length of funnel-tube..............- 3 3 2 3 3 3

the body. The apical sense-organ is situated in the bottom of a wide
but not very deep cleft (text-fig. 6). The 4 auricles are edged by a linear
row of ciliary combs, and arise from the sides of the body at a short
distance above the mouth and close to the sides of the lappets. The
lappets are flat and lanceolate and are each about one-fifth as long as
the entire animal. The 4 subventral rows of ciliated combs are about
twice as long as the 4 subtentacular rows. The combs of cilia are small
and numerous, there being about 80 to 100 on each subventral row and
40 to 60 on each subtentacular row. There is a row of short, simple
tentacles on each side of the mouth, extending upward along the sides
of the lappets to the bases of the auricles. The tentacle at the center of
each row on the mid-axial line is longer than the others and is provided
with simple, lateral filaments. The edges of the auricles are fringed
with long, closely-crowded cilia. The stomodzum is long and narrow,
and the funnel is short, being about one-fifth as long as the stomodzum.
The chymiferous tubes are of fine caliber, and the windings of the merid-
ional ventral tubes in the oral lappets are very simple, not complex as in
B. infundibulum. The oral lappets are provided with a delicate network
of longitudinal and transverse muscle fibers. The gelatinous substance is
of very delicate consistency and is either transparent or diffusely tinged
by a faint pink. The peripheral chymiferous tubes are of a more decided
pink and in the lappets these tubes often display masses of intense pink
color, probably due to products of digestion or excretion.

When about 7 mm. long (fig. 16, plate 5), the body is oval with the
two poles of about equal bluntness. Two long, flexible tentacles arise
from the middle points of the sides of the body. These tentacles are
highly contractile and give rise to numerous short, lateral filaments.
They arise from the surface of the body and are not protected by sheaths.
The apical sense-organ consists of a capsule containing a small mass
of hyaline concretions. It lies at the bottom of a shallow depression.
There is as yet no trace of the lappets, but the adjacent meridional sub-
ventral tubes have fused, forming simple, closed loops. The 4 meridi-
onal subtentacular tubes have joined with the circumoral vessel. When

24 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

the animal is 8 mm. in length (fig. 19, plate 5) the oral lappets begin
to develop as 2 short flaps, each about one-fifth as long as the animal
itself. The 4 auricles appear as short ciliated projections from the sides
of the body over the subtentacular canals. The subventral canals form
simple loops in the substance of the lappets. The 8 rows of ciliated
plates are still of equal length each to each.

This species is found along the coast of Florida and in the West
Indies and probably extends as far north as Charleston, South Carolina.
It is also found in the Mediterranean. Upon calm, hot days it approaches
the surface in great numbers, but rough weather soon causes it to sink
into the depths. They are often common during the summer, floating
near the surface in shallow water in the Florida-Bahama region.

Fic. 6.—Bolinopsis vitrea, 1.25 natural size. Tor-
tugas, Florida, June 21, 1910. Drawn from
life, by the author.

The pink coloration of this form is very variable, some individuals
being translucent and colorless, while others exhibit large, deep-colored
masses of pink pigment in their chymiferous tubes, or pink, diffused
through their gelatinous substance. It is distinguished from the Arctic
B. infundibulum by its blunter aboral apex, its relatively longer oral lobes,
the much simpler windings of the meridional ventral vessels in its oral
lobes, and its commonly present pink coloration. Its eggs are cast out
in great masses during the warm months and the young are common in
spring and summer. Altogether, it is the commonest ctenophore of the
Bahama-Florida region.

Fic.

Fic.

Fic.

Fic.

PLATE 5.
Bolinopsts vitrea.

16. Larva of Bolinopsis vitrea, 7 mm. long, in the Cydippide-
stage. Tortugas, Florida, May 17, 1899.

17. Surface view of apical pole of larva represented in figure 16.
ad, adradial canals; c, subtentacular meridional canals;
cpr, perradial canals; 7, interradial canals; p, pole-plate;
tv, tentacular canals; v, subventral meridional canals.

18. Surface view of mouth of larva shown in figure 16. Letter-
ing asin figure 17. gc, paragastric canals; st, mouth open-
ing and stomodzum.

19. Young Bolinopsts wtrea, 8 mm. long with oral lobes and
auricles beginning to develop. Tortugas, Florida, May
21, 1899.

Drawn from life, by the author.

GTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA PLATE 5.

V
\
2a
7

B.Meisel lith. Boston.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 25

Bolina elegans Mertens, 1833 (Mém. Acad. Sci. St. Pétersbourg,
Sci. Math. Phys. et Nat., sér. 6, tome 2, p. 513, Taf. 6, fign. 1-4), from
the South Seas, is also pink in general color, but the upper parts of the
body are covered with numerous small papilla and these are absent in
the Florida species. B. hydatina of Chun is evidently the immature B.
vitrea from the Mediterranean.

Fic. 7.—Bolinopsis vitrea. Adult, 1.25 times natural size. Show-
ing oral lobe expanded, and canals. Tortugas, Florida, June,
1910. From life, by the author.

A solution of 0.6 molecular sodium chloride inhibits and soon stops
the movements of the cilia of B. vitrea, but solutions of o.4 molecular
magnesium chloride or molecular magnesium sulphate which are isotonic
with the sodium chloride of sea-water have an opposite effect, for they
produce an abnormally rapid movement of the cilia, each comb beating
independently, and the coérdination of the rows of combs being destroyed.
In solutions containing potassium in weak concentration the combs stop
momentarily and then resume their movement.

This converse relation between ciliary and muscular movement may
be explained in the following manner: When the muscles contract, the

26 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

combs of cilia overlying them cease to beat and resume their rhythm
only when the muscles relax, for if the surface of the ctenophore be
pressed or stretched the ciliated combs of the stretched area are in-
hibited. Thus magnesium does not stimulate, but weakly subdues
ciliary movement; but its inhibitory effect upon nerves and muscles is
more marked, and it soon relaxes the muscles, thus lessening the mus-
cular tonus and reducing the pressure which is normally exerted by the
epithelium upon the cilia-bearing cells ; and then the cilia beat unhin-
dered as do isolated cells when separated from the epithelium. Thus
the so-called ‘‘ converse relation between ciliary and muscular move-
ment ’’ is due to mechanical causes, not to converse chemical effects of
the cations of sea-water upon muscles and cilia respectively.

Genus MNEMIOPSIS L. Agassiz, 1860.
(?) Alcinoé, Ranc, 1828, Mem. Soc. d’Hist. Nat. de Paris, tome 4, p. 168.
(?) Mnemia, EscuscHo.tz, 1829, Syst. der Acalephen, p. Vv, 31.
nemiopsis, Acassiz, L., 1860, Cont. Nat. Hist. U. S., vol. 3, pp. 269, 290.—

Acassiz, A., 1865, North Amer. Acal., p. 19.—Cuun, 1880, Ctenophoren Golfes

von Neapel, p. 290; also, 1898, Ctenophoren der Plankton-Expedition, p. 25.—

Mayer, 1900, Bull. Museum Comp. Zool. at Harvard College, vol. 37, p. 9.—

Moser, 1908, Abhandl. Akad. Munchen, Suppl. Bd. 1, Abhandl. 4, p. 59.

GENERIC CHARACTERS.

This genus of the Lobate is closely allied to Bolinopsis, but is dis-
tinguished by having 4 deep, lateral furrows which extend upward from
the level of the mouth along the edges of the oral lobes to about the level
of the apical sense-organ. A lateral branch from the paragastric vessel
extends upward along each of these grooves, and numerous short, simple
tentacles arise along the length of this canal. The outer edge of an
auricle also extends upward along each groove and this edge is bordered
with numerous cilia.

The type species is Mnemiopsis gardeni L. Agassiz, from Charleston,
South Carolina.

Future studies will probably demonstrate that Alcinoé vermiculata
Rang, 1828, found in April in the entrance to the Bay of Rio Janeiro,
Brazil, is identical with Agassiz’s genus Munemiopsis. Certainly it
has all of the external characters of Agassiz’s genus, but Rang does not
figure or describe its internal anatomy, so that there is a possibility that
we may be able to separate it generically from Mnemiopsis. Rang’s
ctenophore was redescribed by Eschscholtz, 1829, under the name Mnemia
schweiggert. Another species from the southern hemisphere in S. lat.
44° 12’, W. long. 56° 30’, north of the Falkland Islands, is described and
figured by Mertens, 1833, under the name Alcinoé rosea. JI am strongly
inclined to believe that Agassiz’s Munemiopsis should be called Alcinoé,
but I hesitate to act in the matter owing to our imperfect knowledge of
the forms described by Rang, Eschscholtz, and Mertens.

Mnemiopsis leidyi A. Agassiz. (Figs. 20 to 46, plates 6 to 8.)

Mnemiopsis leidyi, Acassiz, A., 1865, North Amer. Acalephe, p. 20, figs. 22-24.—
FewkeEs, 1881, Bull. Mus. Comp. Zool. at Harvard Coll., vol. 8, No. 8, p. 173:
plate 8, figs. 1-11; also, Ibid., vol. 9, p. 291, plate 1, figs. 1-9.—Cuun, C.,
1898, Ctenophoren der Plankton-Expedition, p. 25.— HunTER, 1904, Biol.
Bulletin, Woods Hole, vol. 6, p. 324.—PARKER, 1905, Jour. Exper. Zool.,
vol. 2, p. 407.—Lituiz, R. §., 1908, Amer. Jour. Physiol., vol. 21, p. 200.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 27

The adult animal (figs. 42, 43, 46, plates 7 and 8) is about 100 mm.
in length, specimens larger than this being rare. When seen from the
narrow side, the general outline of the body is almost ellipsoidal. A view
of the broad side, however, shows a pear-shaped outline, this being due
to the wide-flaring oral lappets. The aboral apex is not so acute as in
Bolinopsis infundibulum, and not so blunt as in Lesueuria hyboptera. The

Fic. 8.—Sense-organ of Mnemiopsts leidyi. From life, by the author,
at Newport, Rhode Island. ad, adradial canals; c, cilia at aboral
end of stomodzeum; f, funnel or entodermal center of gastro-
vascular system; ft, axial-funnel canal; g, paragastric canal;
t, interradial canal; mu, connective tissue strands; p, pole plate;
st, stomodzeum; t, tentacular canal.

apical sense-organ (text-fig. 8) contains a mass of highly refractive con-
ccretions, and lies at the bottom of a moderately deep cleft. The oral
lappets are each about two-fifths as long as the entire animal and are
even wider than they are long. The 4 auricles are flat and ribbon-like,
and about one-fourth as long as the body of the animal. Their centrif-

28 CTENOPHORES OF THE. ATLANTIC COAST OF NORTH AMERICA

ugal (abaxial) edges lie along a deep groove which extends down the
sides of the body adjacent to the oral lappets, from the mouth to the
level of the apical sense-organ. The auricle side of this groove is ciliated,
while the opposite side is provided with numerous short, simple tentacles.
which lie immediately over 4 lateral tubes that diverge from the para-
gastric vessels. This long, deep furrow at once distinguishes Muemiopsis
from Bolinopsis. Both sides of the long, slit-like mouth are bordered
with a row of short, simple tentacles which are continuous with those
of the deep, lateral furrows. The central tentacle on each side is longer
than the others and gives rise to lateral filaments. The 4 rows of ciliated
combs leading to the auricles are only about half as long as the 4 rows.
extending down the outer surface of the oral lobes. The combs are small,
but numerous. The stomodzum is long and narrow and is provided with.
cilia at its aboral end. The axial funnel-tube is only about one-fifteenth
as long as the stomodeum. The peripheral canals are of fine caliber,
and the meridional ventral canals give rise to simple windings in the
oral lappets. The oral lappets are provided with delicate transverse
and longitudinal muscle fibers. The lappets are of no appreciable aid.
in swimming, this being performed almost entirely by the action of the
combs of cilia. The creature is almost colorless, being of a slightly milky
translucent hue. The ciliated combs sparkle with brilliant iridescence
by day and glow with an intense green light when the animal is disturbed.
at night. The gelatinous substance of this ctenophore is often infested
by a pink colored, worm-shaped, parasitic, larval actinian (Edwardsia).

The development (figs. 20-41, plates 6 and 7) has been studied by
A. Agassiz. As in other ctenophore, the animal is hermaphroditic,
and the egg is spherical and is enveloped by a thin, structureless mem-.
brane which is widely separated from the surface of the egg (see fig. 20,
plate 6). The deeper portions of the egg are filled with large, slightly,
refractive masses of food-yolk, between which there is a delicate reticulum
of protoplasm. The superficial layer of the egg is composed of finely
granular protoplasm. The segmentation is total but unequal. The
first two cleavage planes are meridional and cut in the direction of the
longitudinal axis of the future ctenophore from the animal to the vege-
tative pole. The third cleavage is also meridional, but shifted to one
side and the other, and it divides the embryo into 8 cells, 4 large central.
and 4 small lateral cells, the 4 small cells being at the extremity of the
longer axis of the embryo, which becomes the tentacular axis of the
future ctenophore. The 4 small, laterally placed cells then migrate
upward toward the animal pole. The next cleavage is equatorial and cuts.
off 8 small, uppermost cells from 8 large, yolk-laden macromeres. The
small cells then begin to divide rapidly and to extend downward, cover-
ing over the 8 macromeres, thus beginning to form a gastrula by epibole.
Meanwhile the cleavage cavity remains open, so that the cells form a.
Ting surrounding a central space which extends as an opening from the
vegetative to the animal pole. The animal pole corresponds to the aboral:
apex of the future animal. The small micromeres which are to form the
ectoderm envelop the macromeres, forming a cap which overlies them
(figs. 22 to 24, plate 6). Before the macromeres are inclosed, however,
they divide, giving rise to a number of small cells, some of which form.

PLaTeE 6.

Development of Munemiopsis leidyi. Agassiz Laboratory, Newport,
Rhode Island, July 27 to August 4, 1892.

Fic. 20. Newly laid egg.

Fic. 21. View of animal pole in a late segmentation stage. About
6 hours after egg is laid.

Fic. 22. Side view of stage slightly older than figure 21.

Fic. 23. View of vegetal pole of an embryo about 7 hours old, slightly
older than that shown in figure 22.

Fic. 24. Side view of an embryo about 7 hours old.

Fic. 25. First appearance of ciliary combs in 4 double rows.

Fics. 26 and 27. Median sagittal optical sections to show arrangement
of cells. Ectoderm dotted and composed of many small
cells, individual cells not being shown in figure. Ento-
derm cells large and drawn in outline.

Fics. 28 and 29. Development of concretions at aboral pole of embryo.
Figure 29 shows the same animal half-hour older than that
shown in figure 28. Note remarkable development of
cilia during the interval.

Fics. 30-32. Oral, aboral, and side views of embryo about 3 hours
older than those shown in figures 28 and 29.

Fic. 33. Embryo still within the egg-envelope, about 24 hours old.
No tentacles have yet developed.

Fic. 34. Embryo with tentacles, about 30 hours old and still within
the egg envelope.

Fic. 35. Newly-hatched embryo about 30 hours old. The animal is
now in the Cydippide-stage.

Fic. 36. Aboral pole of an embryo about 32 hours old, showing de-
cided lateral compression, the tentacular axis being now
the wider, as in Mertensia, although the reverse is the case
in the mature animal.

Fic. 37. Side view of an embryo about 32 hours old, showing muscular
strands.

Fic. 38. About 36 hours old. View of aboral pole, showing a stage
wherein the stomodzal axis has become nearly as wide as
the tentacular.

Fic. 39. Young Munemiopsis leidyi, 5 mm. long. The oral ends of the
2 paragastric canals are now L-shaped, the 2 meridional
ventral canals of each side are fusing at their oral ends.
The tentacles are migrating downward toward the mouth
and the oral lobes are about to develop.

Drawn from life, by the author.

CTENOPHORES OF THE ATLANTIC GoaST OF NoRTH AMERICA PLATE 6.

B.Meisel lith. Boston.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 29

ectoderm, while others lie at first at the lower (oral) pole of the embryo
but are carried inward by invagination until they come to lie immediately
under the apical sense-organ, where they give rise to the mesoderm.

The stomodeum is formed by invaginated ectoderm derived from
the original macromeres (figs. 26, 27, plate 6). The axial funnel-tube and
peripheral chymiferous vessels are of entodermal origin and are formed
from the macromeres after the formation of the primitive mesodermal
cells. The body becomes egg-shaped, the aboral pole being broadest.
There is considerable lateral compression, the tentacular axis being wider
than the sagittal. When the animal is mature, however, the reverse is
the case, for then the tentacular diameter is the narrower. The combs
of cilia appear as 4 double rows of simple lashes. These soon separate,
however, forming 8 rows of ciliated plates. The apical sense-organ is at
first situated within a very shallow depression at the aboral pole, but
this cleft gradually deepens until the organ becomes sunken deeply
within a furrow. When about 30 hours old, the embryo has acquired
4 double rows of cilia, a well-developed pair of lateral tentacles, and a
large, apical sense-organ (fig. 34, plate 6). The entodermal part of the
gastro-vascular system consists of 6 lateral diverticula from a central
chamber; 2 of these lateral branches lead into the bases of the tentacles
and the other 4 lead outward toward the 4 double rows of cilia. The
ectodermal buccal pouch, or stomodeum, has become a long, laterally
compressed tube, with its broad axis go° from the tentacular axis of the
animal. Until this time the animal swims about quite freely within the
egg-envelope, and even in this stage its cilia may be observed to beat in a
normal manner and the tentacles to elongate or contract in response to
stimuli. Soon after this the larva breaks through the egg-envelope and
escapes into the water. Here it goes through stages which are so close
to those of the young Pleurobrachia that it is almost impossible to dis-
tinguish the embryos of the two species apart. The tentacles acquire
numerous lateral filaments and elongate greatly, as in Pleurobrachia.
When the animal is 5 mm. long the oral lobes begin to develop as two
simple outgrowths on both sides of the mouth in the sagittal plane of
the animal (see fig. 39, plate 6). The sagittal diameter is then somewhat
longer than the tentacular diameter, and from this time onward the dis-
parity between these two diameters increases at the expense of the
tentacular diameter. At the time when the oral lobes begin to develop,
the meridional ventral canals and the paragastric tubes begin to elongate
downwards (fig. 39, plate 6). The former give rise to the characteristic
loops in the oral lobes, while the 2 gastric tubes become J-shaped at
their ends and finally extend up the lateral furrows which lie adjacent
to the sides of the lobes, forming a circumoral vessel around the lobes.
The 4 meridional vessels extend downward and fuse with the circum-
oral vessel. The primary tentacle-bulbs migrate downward at the same
time and come to lie close by the sides of the mouth, and they carry
the tentacular canals down with them. The auricles appear last of all,
after the lobes have developed to some extent. When 10 mm. in length
the animal is ellipsoidal in outline and the condition of the lobes and
auricles is similar to that in the adult of Bolinopsis (see fig. 40, plate 7).

30 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

Afterwards the deep, lateral furrows extend upward to the level of the
apical sense-organ and the animal acquires the characters of Mnemiopsis.
Thus the larve pass successively through stages characteristic of Pleuro-
brachia, then of Bolinopsis, and finally Mnemiopsis.

This species is common throughout the summer off the southern.
coast of New England and is also found as far south as the Carolinas.
It appears not to occur north of Cape Cod, Massachusetts.

According to Hunter, 1904, Mnemiopsis leidyi rests at the surface
with its mouth upward, and at the bottom of the aquarium with mouth
downward. A constant electrical current of from 0.5 to 3 volts causes
it to turn the aboral pole toward the anode and to move toward the
cathode. It is relatively more resistant to decrease than to increase in
temperature of the water. Responses to electrical stimulation under
conditions of greater heat than normal show decrease in reaction time
up to about 29° C., then rapid increase in reaction time. A slow increase
in reaction time occurs below 15° C.

Parker, 1905, finds that in Mnemiopsis and Pleurobrachia the combs
beat metachronally, beginning at the aboral ends of the rows.

In Mnemiopsis the 2 rows of plates belonging to the same quadrant
beat in unison. This is often true in Pleurobrachia, although in this
form all 8 rows may beat independently.

The propagation wave shows scarcely any evidence of reversal in
Muemiopsis, but often reverses in Pleurobrachia. Reversal of the effec-
tive stroke of the plates was never observed in Mnemiopsis or Pleuro-
brachia.

A transverse cut across a row of combs in Mnemiopsis isolates the
oral part of the row, which, however, soon recovers, although it beats
independently of other rows. An isolated plate will beat if it retain a
small amount of basal protoplasm.

Cooling part of a row to 5° C. brings the movements of the cooled
plates to a standstill, but does not interrupt transmission of the impulse
to beat. Stretching of a part of a row also prevents movement, but
does not prevent transmission. The transmission impulse is, therefore,
mainly if not wholly nervous in nature, although probably supplemented
by mechanical transmission from one comb to its neighbor.

R. S. Lillie, 1908, finds that in Mnemiopsis mechanical stimulation
arrests the automatic activity of the swimming plates. This, however,
does not occur if calcium be absent, and the effect decreases as the cal-
cium is decreased.

Chun, 1880, finds that the litholite concretions of the sense-organs
of Ctenophore are composed of calcium phosphate, whereas I find that in
Scyphomeduse they consist of calcium oxalate. The functions of the
concretions in respect to movement must therefore be quite different in
the ctenophore and scyphomedusz.

In this connection it is of interest to state that Samassa, 1892
(Archiv far mikroskop. Anat., Bd. 40), finds that the litholites are not
cell products, but are contained within epithelial cells which usually
retain their nuclei, and are set free from the epithelium and gathered
together in a mass at the apical pole. It will be recalled that Verworn,

PLATE 7.

Mnemiopsis leidyi. Agassiz Laboratory, Newport, Rhode Island,

Fic. 40.

Fic.
Fic.
Fic.

Fic.
Fic.

41.
42.
43.

44.
45.

summer of 1892.

Young M. leidyi, 10 mm. long with developing oral lobes
and auricles. The embryo is now in the Bolinopsis-
stage.

Sense-organ of the ctenophore shown in figure 4o.

View of broad side of a mature M. leidyi. Natural size.

View of auricular side of a mature M. leidyi. Natural size.
Lobes not expanded.

Half-grown M. leidyi; side view, natural size.

View looking down upon mouth of M. leidyi. Natural size.
Showing expanded lobes and auricles.

Drawn from life, by the author.

GTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA PLATE 7.

B. Meisel {ith Boston,

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 31

1891 (Pfliger’s Archiv fur Physiol., Bd. 50, p. 423), concludes that the
apical sense-organ in Beroé does not subserve the sense of hearing, but
controls the orientation and equilibration of the animal. Without the
sense-organ the animal assumes unnatural positions in the water.

I find that the effective stroke of the cilia of Bolinopsis vitrea may
sometimes be reversed by a solution composed of 0.625 molecular (100
NaCl+11.6 MgCl,), so that the animal swims backward, 7.e., mouth-end
forward.

Mnemiopsis mccradyi Mayer. (Fig. 48, plate 8.)

Mnemiopsis mccradyi, MAYER, 1900, Bull. Museum Comp. Zool. at Harvard Col-
lege, vol. 37, p. 9, figs. 22, 23, plate 6.

Fic. 9.—Mnemiopsis mccradyi, view of mouth, auricles, and oral lobes.
au, auricle; dg, axial extension of paragastric canal; fg, oral forks
of the paragastric canals; g, paragastric canal; m, mouth; mn,
muscular net in the oral lobes; mst, meridional subtentacular
combs; msv, meridional subventral combs; #, tentacular canal;
ten, axial tentacle; tr, tentacular ridge. From life by the author.
Port Royal, Jamaica, May, rgrt.

The animal is about 100 mm. long, and the general form of the body
is very similar to that of M. leidyt. The lateral compression of the body
is, however, more marked, while the gelatinous substance is far more
rigid and of a decided greenish-amber color and opalescent not trans-

32 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

parent as in M. leidyi. The outer surface, instead of being smooth as
in M. letdyi, is besprinkled by numerous small warts, which are, how-
ever, not found between the subtentacular rows of combs, but are well
developed on the sides of the oral lobes. The windings of the meridional
ventral canals through the oral lobes are far more complex than in M,
Jeidyi, and the canals are of a decided purple color. This is the most
tigid ctenophore known. The animal may be removed from the water by
hand without suffering injury. The mature ova are similar in form to
those of M. leidyi. I first found this ctenophore in Charleston Harbor,
South Carolina, late in summer, and again in considerable numbers off
Port Townsend in Kingston Harbor, Jamaica, late in March, 1909, and
in May, 1911. It is said by local fishermen to be common throughout
the summer at Jamaica. It lives well in aquaria, and is doubtless the
most favorable form among ctenophore for physiological experiments.
It is greedily devoured by the scyphomedusa Dactylometra. When 53
mm. long the young animal is of a glassy transparency, and has all the
structural features of Mnemiopsis.

The following table gives the dimensions in millimeters of two
mature specimens of this ctenophore found off Port Henderson, Kings-
ton Harbor, Jamaica:

Mar. 22, 1909. May 1, torr.
Total length of body .........ecceeeec ee aeeee 108 96
Stomodeal diameter .........seeeeeeer eens 44 44
Tentacular diameter .... 24 34
Length of oral lobes........ 39 25
Length of auricles........ceceseeeeeceeeveres 26 29
Depth of cleft of sense-organ........-.sees0. 1s 15
Length of subtentacular rows of combs..... 60

This species is distinguished from M. leidyi by the extraordinary
tigidity of its gelatinous substance, the complex windings of its merid-
ional ventral canals in the oral lobes, its amber-greenish opalescent color,
and the wart-like protuberances over the sides of the oral lobes.

If this ctenophore be placed in 33 parts of sea-water + 67 parts of
o.4 molecular magnesium chloride the cilia cease to beat for about 3
minutes, after which waves begin to course with abnormal rapidity down
the rows of combs, the movement being coordinated as in natural sea-
water, but of far greater energy and speed; the stimuli following closely
one upon the other so that several waves are commonly traveling down
the same row of combs at one and the same instant. This abnormally
rapid movement of the cilia continues more than 15 hours, the muscles
during all this time being incapable of contraction.

If, on the contrary, the ctenophore be placed in 33 sea-water + 67
parts of 0.625 molecular sodium chloride the rows of combs cease to beat
at the end of 12 minutes and the cilia along the auricles at the end of
19 minutes, while the muscles are highly excited and contract spas-
modically more than half an hour. The auricles lack muscles and are
almost incapable of contracting. A local contraction of the muscles
causes the cilia overlying them to cease beating until the muscles relax,

PLATE 8.

Fic. 46. Munemiopsis leidyit. Twice natural size, with fully expanded
oral lobes. Agassiz Laboratory, Newport, Rhode Island,
September 19, 1896.

Fic. 47. Mnemiopsis gardeni. Twice natural size, with fully ex-
panded oral lobes. Core Sound, North Carolina, Novem-
ber 18, 1904.

Fic. 48. Mnemiopsis mccradyi. Natural size, lobes not fully ex-
panded. Charleston Harbor, South Carolina.

Drawn from life, by the author.

CTENOPHORES OF THE ATLANTIC Coast oF NoRTH AMERICA PLATE 8.

a, Fala,
RHAAraAA eH LeeanraeaaaAAe:

Ee

B.Metsel (ith. Boston.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 33

for when the ciliated epithelium is stretched through the contraction of
the underlying muscles the cilia are stopped, but if the muscles be re-
laxed, as by magnesium, the surface tension is reduced and the cilia
are free to beat.

Fic. 10.—Mnemiopsis mcecradyi, from life by the author. Natural size. Let-
tering as in fig.g. Port Royal, Jamaica, May 1, grr.

Mnemiopsis gardeni L. Agassiz. (Fig. 47, plate 8.)

Munemiopsis gardeni, Acassiz, L., 1860, Cont. Nat. Hist. U.S., vol. 3, pp. 269, 290,
figs. 95, 96.—Acassiz, A., 1865, North Amer. Acal., p. 20, figs. 20, 21. —Cutn,
C., 1898, Ctenophoren der Plankton-Exped., p. 25.

(?) Bolina littoralis, McCravy, 1859, Proc. Elliott Soc., Charleston, vol. 1, p. 254,
plate 14, figs. 1-14 (development).

This is a small species, being only 35 to 4o mm. long when mature.
The oral lobes are of very small size, being only one-fifth to one-sixth as
long as the body of the animal. The auricles, however, are well developed,
being relatively about as long as in M, leidyi and about one-third as long
as the entire body of the animal. There is considerable lateral compres-
sion, the sagittal diameter being about 2.5 times as great as the tentacular.
The 4 deep lateral furrows extend from the level of the mouth about
three-quarters the distance up the sides of the body. They are not as

34 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

long, however, as in M. leidyi and do not quite reach to the level of the
apical sense-organ. The 4 meridional ventral rows of combs which ex-
tend out over the oral lobes are about one-third longer than the 4 rows
which lead to the auricles. The meridional ventral rows begin also ata
greater distance from the apical sense-organ than do the meridional sub-
tentacular combs. The windings of the meridional ventral canals in the
oral lappets are very simple, thus differing markedly from the conditions
seen in M. leidyi and M. mccrady. The apical sense-organ is sunken
within a deep cleft about one-sixth as deep as the total length of the
body.

The surface of the oral lobes and the adjacent parts of the body
are besprinkled regularly with small, low, discoidal warts. The animal
is translucent and slightly bluish in color. It is very abundant along the
coast from Chesapeake Bay to Florida, being especially common in bays,
sounds, and estuaries where the water is slightly brackish.

I have never seen any intergrading forms between this southern
species and the somewhat more northerly M. leidyi. M. leidyi is a
creature of the pure sea-water along the outer shores, while M. gardeni
thrives in protected bays and brackish waters.

Genus LEUCOTHEA Mertens, 1833.

Eucharis, preoccupied by LaTREILLE for Hymenoptera in 1804.

Eucharis, used for Mollusca by PéRon in 1807.

Eucharis, EscuscHoutz, 1825, Isis, p. 742; also, 1829, Syst. der Akal., p. 31.—
CHUN, 1880, Ctenophoren des Golfes von Neapel, p. 296.—AGassiz and
Mayer, 1899, Bull. Museum Comp. Zool. at Harvard College, vol. 32, p. 176.—
ALLMAN, 1882, Journal Linnean Soc. London, vol. 16, p. 103.

Beroé, Quoy ET GAIMARD, 1824, Voyage de l’ Uranie, Zool., p. 574.

Alcioné, DELLE CuIajJE, 1829, Mem. Animali senzavert., Napoli, tome 4, p. 7.
Ibid., 1841, Tav. 150.

Leucothea, MERTENS, 1833, Mém. Acad. Sci. St. Pétersbourg, Sci. Math. Phys. et
Nat., sér. 6, tome 2, p. 499.

Chiaja, Lesson, 1843, Hist. Zooph. Acal., p. 77.

GENERIC CHARACTERS.

Lobatz in which the oral lobes are of large size and contain com-
plexly-winding chymiferous tubes. The auricles are long, thick, and
coiled in helices with the cilia extending in a loop up and down one side.
The outer surface of the body and lobes are covered with long, conical
papilla. The aboral blind ends of the subtentacular meridional canals
are long. The 2 median tentacles are very long; 2 long, blindly ending,
pit-like depressions extend inward from above the tentacles nearly to
the level of the funnel.

This genus is descended from a Bolinopsis-like ancestor, for it passes
through a stage in which it can not be distinguished from Bolinopsts.
The large papilla which cover the external surfaces of the oral lobes and
of the body are late in developing and do not appear until the animal
has passed through the Bolinopsis stage. In this connection it is interest-
ing to observe that Bolinopsis elegans of Mertens, 1833, is covered with
small papilla on the whole outer surface of its body, save only upon the
lower parts of the oral lobes.

The name Eucharis is preoccupied, having been used for Hymenop-
tera by Latreille, 1804. Alcinoé of Delle Chiaje, 1829, can not be used,

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 35

for Rang, 1828, applied it to designate a Mnemiopsis-like ctenophore.
Leucothea Mertens, 1833, is thus the oldest distinctive name applied to
the genus.

The genus Leucothea is distinguished from all other Ctenophore
by the 2 remarkable blindly-ending sacs which form a pair of long narrow
pits open to the outer world below and extending inward and upward
from above the tentacle-bulbs nearly to the level of the funnel.

The type species is Leucothea multicornis of the Mediterranean.
This species is most admirably figured and described by Chun, 1880
(Ctenophoren des Golfes von Neapel, pp. 47, 122, 143, 151, 242, 296,
Taf. 4,5 and 9), who found that when the water was unusually warm the
larve just out of the egg and still in the Cydippe-stage produced ripe
ova which developed into normal but small embryos, resembling those
produced by the adult except that they were only about half the normal
size.

Leucothea ochracea sp. nov. (Figs. 49 to 54, plates 9, 10.)

Eucharis multicornis, FEwKEs, 1882, Bull. Museum Comp. Zool. at Harvard Col-
lege, vol. 9, p. 251, plate 7, figs. rz, 12.

This Florida species differs from the Mediterranean Leucothea multt-
cornis in its smaller size and simpler windings of the meridional ventral
canals through the oral lobes, and by having 4 prominent, yellow areas,
a pair in the gelatinous substance of the outer sides of each lobe; but it
is chiefly distinguished by having simple, lateral filaments upon its prin-
cipal tentacles, these being absent in the Mediterranean species.

It will be remembered that Chun, 1880, found that the larva of the
Mediterranean Leucothea passes through a Cydippe-like stage wherein it
has a pair of tentacles provided with lateral filaments as in Mertensia or
Pleurobrachia. Later the larva passes into a medusiform stage, in which
it completely loses its tentacles, and next it passes into a Bolinopsis stage
in which the tentacles reappear, but without lateral filaments. The
Leucothea stage then ensues, wherein the papilla develop over the sur-
face of the body and the blind sacs sink inward into the sides of the body
above the bases of the 2 principal tentacles.

I have seen Leucothea multicornis in considerable numbers at Naples,
and have never observed lateral filaments upon the tentacles of the adult,
nor does Chun mention or figure them in his superb monograph. Their
constant presence in the Tortugas ctenophore may therefore be con-
sidered as of specific significance. Also I have never seen yellow areas
on the sides of the oral lobes in the Mediterranean Leucothea nor does
anyone figure them, but these are very characteristic of the Florida
Leucothea ochracea and render it a conspicuous object as it floats in the
water.

The dimensions of the Florida L. ochracea as compared with those
of the Mediterranean L. multicornis are here given in millimeters. The
dimensions of the Mediterranean ctenophore are taken from-a specimen
studied by me at Naples on December 8, 1907. According to Chun,
however, the Mediterranean Leucothea becomes about 200 mm. long and
240 mm. across the oral lobes, thus becoming much larger than the

36 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

Florida form. I here give the dimensions of a small specimen from
Naples, because it corresponds more nearly in size to those found at
Tortugas.

Leucothea
multicornis
from Naples,

Leucothea ochracea
from Tortugas.

Potal lengths i2 oy wes ewor aries ob ocean Seas 96 88
Width of body above oral lobes in tentacular diam-
Ch SOO eee eee eee re 20 26
Width of body above oral lobes in sagittal diameter 33 41
Width across expanded lobes.............00 0000s IIo 85 not fully
: expanded.
Length of auricles (approximate)..............05. 40 staneve
Length of stomodeum........... cee ee eee eens 44 Sate
Depth of sense-organ Cleft.........eesee eee eeee ee 10 16
Length of body from aboral apex to mouth....... 58 72
ngth from aboral apex to origin of oral lobes.... 39 45
General Colo tis sts cje:ccaierara/acaredaleere A evayasalods oiaveverang rile, Transparent with 4/| Dull translucent
yellow spots upon| brownish without
oral lobes. yellow spots on
oral lobes.

It is somewhat surprising to find these marked differences between
the Mediterranean and the Tortugas forms of Leucothea, for it has long
been known that the Mediterranean form is widely spread over the warm
parts of the Eastern Atlantic and has been recorded from the Canaries,
Azores, and South Equatorial Stream. Fewkes, 1882, observed the
Florida Leucothea and states that it is more transparent than the Medi-
terranean form. This statement is true if we except the 4 opaque yellow
spots in the gelatinous substance of its oral lobes, which in so far as I
have observed appear always to be present.

The Florida species is not common and comes to the surface in num-
bers only when the ocean is unrippled after days of calm. The least
ibreeze suffices to produce sufficient rippling to cause it to sink into the
depths. In this habit it resembles Leucothea grandtformis of the Fiji
Islands. The Fijian form is, however, anatomically speaking, more
nearly allied to the Mediterranean species. It is remarkable that the
Mediterranean Leucothea appears to be far less troubled by waves and
is often found quite near the surface in fairly rough weather. The ex-
treme tenuity of this Florida ctenophore is remarkable, for even a gentle
current suffices to tear it apart. I have seen it only in spring and summer
at Tortugas.

But little stress should be laid upon the presence of the 4 yellow
areas upon the lobes of the Tortugas Leucothea and we may neglect it
as a specific character; for it is possible that this yellow coloration may
be due to commensal plant-cells. Unfortunately since this point occurred
to me I have been unable to find any specimens of the ctenophore.
Indeed, Fewkes appears to have found specimens of Leucothea in Florida
waters which lacked these yellow areas and were quite transparent.
Some specimens of Folia at Tortugas have yellow spots at the ends of
the long axis of the body, while others are wholly transparent. In Cestum
amphitrites from the Pacific there are, according to the figures of Mertens,
1833, and Bigelow, 1904, yellow spots at the tips of the long axis of the
body. (See Cestum pectenalis, Bigelow, 1904, Bull. Museum Comp. Zool.

PLATE 9.

Fic. 49. Leucothea ochracea, sp. nov., 1.5 times natural size. Tor-
tugas, Florida, July 3, 1906.

Drawn from life, by the author.

CTENOPHORES OF THE ATLANTIG CoasT oF NoRnHt eee _

i

Dal
Prooeowster
Ap a

Ly

a)

B. Meisel lith. Boston,

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 37

at Harvard College, vol. 39, p. 267, plate 8, fig. 30.) Also Chun, 1880
(Ctenophoren des Golfes von Neapel, p. 242), found yellowish-green para-
sitic cells of alge in the meridional canals of Euchlora which resemble
the yellow cells of Radiolaria.

The histologic structure of the papille of Leucothea is described by
R. Hertwig, 1880, Jena. Zeit. fir Naturw., Bd. 14, p. 334, Taf. 21, Fig. 3.

Genus OCYROPSIS (nom. nov.).

Ocyroé, presecupied in 1809, for meduse by Péron and Lesuzur.

Ocyroé, RanG, 1828, Mém. Soc. Nat. Paris, tome 4, p. 172.—LeEsson, 1836, Annales
des Sci. Nat., sér. 2, tome 5, p. 250.—FEWKES, 1882, Bull. Museum Comp.
Zool. at Harvard College, vol. 7, p. 252.—CuuN, 1880, Ctenophoren des Golfes
von Neapel, p. 290.—MoseEr, 1903, Ctenophoren der Siboga-Expedition, p. 17,
also, 1908, Abhandl. Akad. Mtinchen, Suppl. Bd. 1, Abhandl. 4, p. 65.

Calymma, EscuscHoLtz, 1829, Syst. der Acalephen, p. 33.—MERTENS, 1833, Mém.
Acad. Sci. St. Pétersbourg, Sci. Math. Phys. et Mae sér. 6, tome 2, p. 508.

Calymma, preoccupied in 1816 for Lepidoptera by HUsner.

GENERIC CHARACTERS.

Lobate with body laterally compressed in the funnel-diameter and
with large, muscular oral lappets. These lappets arise from the sides
of the body in the stomodzal axis, and it is mainly by means of their
contractions that the animal is enabled to swim. The ciliated combs
are not very numerous and in the young animal they tend to lie parallel
with the meridional canals, as in Cestum. In the adult, however, they
usually lie diagonally across the canal. The auricles are well developed
and arise from the body near the sides of the oral lappets. There are no
tentacles in the adult and no tentacular canals.

Three species, O. crystallina, O. maculata, and O. fusca are described
by Rang from the tropical Atlantic. O. crystallina is transparent; O. fusca
uniform dull brown, and O. maculata has 2 large, conspicuous, brown
spots on each oral lobe. Eschscholtz, 1829, describes a form of Ocyropsis
from the Equatorial Pacific under the name Calymma trevirant.

Ocyropsis bears some resemblance to Deiopea of the Mediterranean,
but the oral lobes of Deiopea are smaller and the two meridional ventral
vessels in each lobe end blindly, whereas they form a closed circuit in
Ocyropsis. Also Deiopea has tentacles, and these are absent in Ocyropsis,
wherein there are neither tentacles nor tentacular canals.

The genus is found only in the tropics, being represented in both
the Atlantic and the Pacific.

Unfortunately, the old and well-known generic name Ocyroé can not
be retained for Ctenophore, for it was applied to a medusa by Péron and
Lesueur, 1809 (Annales du Museum, Hist. Nat., Paris, tome 14, p. 354).
The name Calymma given to this ctenophore by Eschscholtz, 1829, is
also preoccupied, having been used by Htibner for Lepidoptera in 1816.
While we must all regret the abandonment of long-used and familiar
generic names, yet the law of priority, which the zoologists of the world
have in congress assembled given their pledge to support, obliges us to
revert to the oldest distinctive name; and as preoccupied names must
be abandoned, no matter how familiar to us in association, it is expedient
that the operation of changing them be executed at once. In place of
Ocyroé I propose the new name Ocyropsis.

38 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

Ocyropsis crystallina. (Figs. 55, 56, plate ro.)

Ocyroé crystallina, RaNG, 1828, Mém. Soc. Nat. Paris, tome 4,

. 172, plate 20,
fig. 4—FEWKEs, 1882, Bull. Mus. Comp. Zool. at Hane College, vol. 9,
No. 7, p. 252, plate 1, figs. 1-6.—MAayEr, 1900, Ibid., vol. 37, p. 81, plate 31,

fig. 105.—MosEr, 1903, Ctenophoren der Siboga-Expedition, p. 17.

Mature animal: (Text-figure 11.) The oral-aboral axis is about

45 mm. long, and this is also the length of each oral lobe. The body is
laterally compressed, the width in the direction of the oral lobes being
about three times as great as that of the transverse axis. The 8 rows
of ciliated plates are short and the plates are few in number. The 4
subtentacular rows are only about two-thirds as long as the 4 subventral
tows. Each subauricular row contains about 20 and each subventral row

Es
z
as
&
:
e

Fic. 11.—Ocyropsis crystallina. Adult, ¢ natural size.
Tortugas, Florida.

about 4o ciliary plates. The cilia contribute but little to aid the animal
in swimming, this being accomplished almost entirely by the flapping
movements of the large, powerful, oral lobes, which by their periodic
closure drive the animal forward. After two or three closures of the
distended lobes there is usually a brief period of rest, followed by several
more movements. A powerful system of radiating and circular muscles is
found in the oral lobes and the flapping movements are caused by their
contraction and expansion. The lobes are 1.5 times as wide as they are
long. The simple apical sense-organ is sunken at the bottom of a shallow
cleft. The auricles are each about 30 mm. in length, flat, and ribbon-
like. Their narrow edges are lined with long cilia. Upon the outer
surface of the oral lobes, immediately over the longitudinal meridional

Fic.
Fic.
Fic.
Fic.

Fic.
Fic.
Fic.

PLATE 10.

. Leucothea ochracea. One of the auricles.

. Leucothea ochracea. One of the papille.

. Leucothea ochracea. View of sense-organ.

. Leucothea ochracea. Portion of one of the rows of combs,

showing follicles of sexual organs and transverse muscles
between each pair of combs.

. Leucothea ochracea. Portion of muscular net of oral lobes.
. Ocyropsis crystalina. Young animal, 8.5 mm. wide.
. Ocyropsis crystallina. Half-grown Ctenophore, 26 mm.

wide. g, paragastric canal.

Drawn from life, by the author.

CTENGPHORES OF THE ATLANTIC COAST OF NortH AMERICA PLATE 10.

B Meisel lith Boston.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 39

canals, there are numerous wart-like protuberances, under which lie
diverticula of the canals. The lateral branches of the paragastric tubes
give rise to complex windings near the inner sides of the auricles, and
the meridional ventral tubes wind complexly in the oral lappets, forming
complete circuits. The stomodzum is flat and its broad side is con-
stricted near the middle. The axial funnel-tube is only about one-
eighth as long as the stomodzum and the meridional canals are of fine
caliber. There are no tentacles and no tentacular vessels. The animal
is of a milky translucent hue, the wart-like protuberances on the oral
lobes being milky-white in color.

Young animal: When the broad, lateral diameter is 8.5 mm.
(fig. 55, plate 10) the creature has assumed all the essential characters
of the adult except that the meridional ventral canals give rise to a simple
loop in the oral lobes and the lateral branches of the paragastric tubes
lead straight into the auricles and do not wind on the way, as in the
adult. There are neither tentacles nor tentacular canals. The auricles
are mere short, flat protuberances. The meridional ventral rows of
cilia consist of only 2 combs each, while the 4 auricular rows contain 3
combs each. The simple capsule of the apical sense-organ lies upon the
surface and is not sunken within a groove, as in the adult. A long,
narrow pole-plate extends out on both sides of the sense-organ. At this
stage the animal moves its oral lobes with great strength and agility
and swims with considerable rapidity.

When the Ocyropsis is 26 mm. in its broad, lateral diameter (fig. 56,
plate 10) there are 11 to 12 combs of cilia in each subventral and the
same number in each auricular row. The lateral, blind branches of the
subventral canals in the lobes have appeared. The stomodzeum is
beginning to be constricted in the middle as in the adult, and the canal-
system begins to assume the characteristic windings.

One often observes yellow or brownish-purple masses in the canals
of this ctenophore, especially in the blind side branches from the merid-
ional ventral vessels. These masses move about more or less in the
currents of the canal-system and disappear after the animal has been
captive, and unfed, in an aquarium for a day or two. I am inclined to
regard them as products of digestion or of excretion.

This ctenophore is capricious in its appearance, but in some years
it is quite common at Tortugas, Florida, swimming in swarms near the
surface in spring and early summer on calm days, and sinking when the
sea becomes rippled.

O. crystallina is widely distributed over the tropical Atlantic, and
it is represented in the tropical Pacific by a closely allied variety with
shorter auricles and longer oral lobes, which has recently been described
by Bigelow, 1904, as O. pteressa.

Rang’s Ocyropsis fusca is a uniformly light brownish or ocher-
colored form from the Cape Verde Islands. It has not been seen since
Rang described it in 1828. Itis possible that this may be an O. crystallina
infested with commensal plant-cells, for such cells often infest the
ctenophores of warm or tropical oceans, although they are unknown
in species inhabiting cold seas.

40 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

Ocyropsis maculata.

Ocyroé tachee, RANG, 1828, Mém. Soc. d. Hist. Nat. de Paris, tome 4, p. 318, planche
20, figs. 1, 2, called O. maculata in the plate.

Ocyroé maculata, Lesson, 1843, Hist. Zooph. Acal., p. 99.—Acassiz, A., 1865,
North Amer. Acal., p. 25.—FEwkes, J. W., 1881, Bull. Mus. Comp. Zool. at
Harvard College, vol. 8, p. 137, plate 4, figs. 1-4.—Acassiz, A., 1888, Bull.
Mus. Comp. Zool. at Harvard College, vol. 15, p. 129, fig. 423.—Cuun, C.,
1898, Ctenophoren der Plankton-Expedition, p. 25.—MoseEr, 1903, Cteno-

horen der Siboga-Expedition, p. 18, 1908, Abhandl. Akad. Mtinchen, Suppl.
d. 1, Abhandl. 4, p. 66.

Calymma trevirani, EscHsCHOLT2Z, 1829, Syst. der Acalephen, Pr 33, Taf. 2, fig. 5.—
MERTENS, 1833, Mém. Acad. Sci. St. Pétersbourg, Sci. Math. Phys. et Nat.,
sér. 6, tome 2, p. 508, Taf. 5, Fign. 1-3.

Ocyroé crystallina, FEwKEs, 1882, Bull. Mus. Comp. Zool. at Harvard College, vol.

9, p. 281.

We have no adequate account of this form, It appears to resemble
O. crystallina, but there are 4 large, brownish spots in the muscular net-
work on the inner sides of the oral lobes. These 4 spots render the animal
very conspicuous. In other respects it appears to resemble O. crystallina.
It is said to be widely distributed over the tropical Atlantic, having been
found by Mertens off the African coast and by A. Agassiz at St. Vincent,
West Indies. It has not been seen at Tortugas, Florida, where O. crys-
tallina is sometimes abundant. Moser records it from Japan. It would
be unprofitable to quote from the inadequate descriptions of this cteno-
phore. A careful study of the animal is greatly to be desired.

Moser, 1908, who studied only preserved specimens, states that the
oral lobes of O. crystallina are evenly rounded, whereas those of O. macu-
lata terminate in two points. Moser also states that she finds a small
tentacle in O. maculata, but this requires confirmation, for no other
observer has seen tentacles in Ocyropsis, and I am inclined to suspect
that she may have had some species of Deiopea.

Genus EURHAMPHA Gegenbaur, 1856.

Eurhamphea, GEGENBAUR, 1856, Archiv fiir Naturgesch., Jahrg. 22, p. 193.—Fot,
1869, Beitrag Anat. und Entwick. der Rippenquallen, Berlin, p. 1.—-CHUN, 1880,
Ctenophoren des Golfes von Neapel, pp. 290, 295.—JONESCU, 1908, Jena. Zeit
far Naturw., Bd. 43, p. 685.

Mnemia, Sars, 1859, Nyt. Magazin for Naturvidensk., Bd. 10, p. 70.

GENERIC CHARACTERS,

Lobatz in which 2 thick, aboral, gelatinous, subconical projections
of the auriculo-tentacular sides of the animal extend upward on both
sides of the apical sense-organ, and each gives rise at its pointed aboral
end to a simple, flexible tentacle. The 4 meridional subtentacular
canals and their ciliary combs extend upward over these projections to
their pointed ends. Numerous excretory pores containing a red fluid
alternate with the combs of cilia and are regularly arranged along the
courses of the 8 meridional canals.

The type species is Eurhamphea vexilligera Gegenbaur, of the
Mediterranean and tropical Atlantic, distinguished by its brilliant red
fluorescent, probably defensive, substance which is cast out with remark-
able suddenness if the animal be disturbed.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 41

Eurhamphea vexilligera Gegenbaur. (Figs. 57 to 59, plate 11.)

Eurhamphea vexilligera, GEGENBAUR, 1856, Archiv ftir Naturgesch., Jahrg. 22,
3 193, Taf. 7, Fign. 1-4.—Fot, 1869, Anat. und Entwick. der Rippenquallen,
erlin, p. 1, Taf. 1, 2.—CHUN, 1880, Ctenophoren des Golfes von Neapel, p.
295.—JONESCU, 1908, Jena. Zeit. fiir Naturwissen., Bd. 43, p. 685, Taf. 24,
vin sa ama 1908, Abhandl. Akad. Minchen, Suppl. Bd, 1, Abhandl.

4; P. 69.

The Eurhampheéa from Florida appears to be identical with that
of the Mediterranean. Specimens so mm. long have occasionally been
found on calm days near the surface at Tortugas in May but most of
them are somewhat smaller than this. The dimensions in millimeters
of an average specimen found at Tortugas, Florida, on May 15, 1906,
and figured in the plate, are as follows: totallength, 39; sagittal diameter,
17; tentacular diameter, 9.5; length from aboral apex to base of auricles,
26. Gegenbaur’s specimens from Messina appear to have been larger
than those we have thus far found in Florida, being 75 to 85 mm. long.

The body is elongated, narrow, and with considerable compression
in the tentacular axis. The aboral apex is drawn out in the form of 2
gelatinous, horn-shaped processes which flank the apical sense-organ
in the tentacular diameter, causing the sense-organ to be sunken at the
bottom of a very deep, narrow cleft. These apical processes give rise,
at their pointed upper ends, to a pair of very delicate, flexible, tapering,
simple filaments, each about one-third as long as the body of the cteno-
phore.

The 4 subtentacular rows of combs extend upward to the tips of the
2 apical horns and the sensory tracts from the apical sense-organ extend
upward along the inner side of each aboral horn to meet them. The 4
subventral rows arise at a much lower level than the 4 others, and com-
mence at the level of the cleft of the apical sense-organ. The subten-
tacular rows of combs are about two-thirds as long as the body of the
animal, while the subventral rows are only a little more than half as long
as the total length of the ctenophore. There are about 30 combs in each
row. The auricles are one-seventh the length of the animal, and are
short, stiff, and stout, with the line of cilia extending in a loop up and
down the inner side, as in Leucothea. The oral lobes are also very short,
being only about one-fourth as long as the length of the body. The cleft,
at the bottom of which the apical sense-organ is placed, is nearly one-
fourth as deep as the length of the entire animal. The sensory pole-plate
and capsule containing the concretions are simple and without appen-
dages. The axial funnel is less than one-seventh as long as the stomo-
dzeum. The chymiferous canals are of very fine caliber.

The 4 adradial vessels to the meridional subtentacular canals join
the latter half-way between the auricles and the aboral apex of the body,
thus at the middle of the rows of combs. On the other hand, the 4 ad-
radial vessels to the meridional subventral canals join the latter at the
upper ends of the subventral rows of combs. The meridional subventral
vessels wind very complexly in the oral lobes, no two individuals being
alike in this respect, and, indeed, the canal in one half of the same lobe
pursues a course which is not the exact reflection of its meandering
curves in the other half

42 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

There are numerous excretory pores along the courses of the merid-
ional vessels (fig. 59, plate 11). These alternate with and open between
the combs of cilia, and also open along the lines of the 4 meridional
subventral canals over the oral lobes below the oral ends of the rows
of combs. These pores contain a brilliant rosin-red oily substance
which is cast out if the animal be handled roughly or be suddenly
disturbed, forming a fluorescent-looking, rosin-red cloud in the water
surrounding the ctenophore. When maintained in an aquarium the ani-
mal soon loses all of this red pigment and becomes quite transparent and
inconspicuous, but in nature its 8 long rows of brilliant red dots render
it most beautiful and conspicuous. We can only conjecture that this
ted substance is of an excretory nature and may possibly serve as a
means of protection.

The lateral branches of the 2 paragastric canals are bordered by
a row of tentacles, all of which are simple and short, except the median
tentacle, which has many short, simple side branches.

The muscular system in the oral lobes is well developed and the
lobes commonly overlap. This ctenophore moves wholly by means of
its ciliated combs. It is extremely soft in texture and a strong current
in the water suffices to tear its tissues. Indeed, I have seen it only when
the ocean has been unrippled for a day or more, after which it may be
found swimming near the surface at sunrise. A slight ripple causes it
to sink out of sight. It was fairly common during May, 1906, at Tor-
tugas, Florida, but all of them were found more than 3 miles from land,
and apparently it is a creature of the deep and open sea.

Eurhamphea appears to be very rare in the Mediterranean. Gegen-
baur found only two specimens, both in a single day in February at
Messina, and Chun found it only once in March, 1875, during the course
of his five years’ study of Mediterranean ctenophore at Naples. At
Tortugas it is rare and occasional, but seems to occur in swarms when
found. I have not seen it later in the year than May. Fol describes
and figures it from the Canary Islands.

Jonescu gives the latest description and figures of this ctenophore,
having found it at Naples in March, 1907.

According to Fol, 1869, the development is similar to that of other
Lobate, the larva passing through a Mertensia stage.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 43

Order CESTIDA: Gegenbaur, 1856.

Callianiride, EscuscuHoitz, 1829, Syst. der Acal., p. 21.

Cestoide@, Lesson, 1843, Hist. Zooph. Acal., p. 68.

Cestide, GEGENBAUR, 1856, Archiv fiir Naturgesch., Jahrg. 22, p. 196.

Taeniate, Acassiz, L., 1860; Cont. Nat. Hist. U.S., vol. 3, p. 292.

Cestide, Fou, 1869, Beitrag Entwick. einigen Rippenquallen, p. 6.

Cestide, CHUN, 1880, Ctenophoren des Golfes von Neapel, p. 300.—VANHOFFEN,
1906, Nordisches Plankton, Ctenophoren, x1, p. 6.

CHARACTERS OF THE ORDER.

Ribbon-shaped ctenophore in which the tentacular axis is mark
edly compressed and the lobular axis correspondingly extended. The 4
subtentacular rows of combs are rudimentary and the 4 subventral rows
greatly extended. The axial tentacles have basal-sheaths.

Thus in the Cestide we find an extraordinary development of the
lateral compression seen in lesser degree in the Lobatze. The funnel-
axis is thus reduced and the stomodzal axis greatly extended. This
causes the subtentacular rows of combs to be rudimentary while the sub-
ventral rows are correspondingly lengthened. The sheaths of the median
tentacles recall the conditions seen in the Cydippide, and indeed the
larve of the Cestidz when hatched from the eggs are Mertensia-like in
appearance with the tentacular axis longer than the sagittal, this being
the reverse of the condition which pertains in the adult.

There are two genera, Cestum and Folia. In Cestwm the narrow,
aboral edge of the animal is arched and the 4 subtentacular meridional
canals extend upward from their points of origin and are provided each
with a very short tract of cilia. They then bend downwards and finally
outwards along the middle of the sides to the ends of the body, where
they join the 4 meridional subventral canals. In the genus Folia the
aboral narrow edge is flat and the 4 subtentacular meridional canals
do not arch upward, but extend straight outward to the ends af the sides
of the body.

The oral branches of each paragastric canal fuse with the meridional
vessels of their own side only, and thus the peripheral canal-system of
each broad side of the body is separated from that of the other side;
there being no circum-oral canal such as is seen in the Lobate.

Species of Cestum are found in all of the warm oceans. Folia is
represented by fF. parallela of the Mediterranean and tropical Atlantic.

Genus CESTUM Lesueur, 1813.

Cestum, LESUEUR, 1813, Nouv. Bull. des Sci., tome 3, p. 281.— EscHscHOLTzZ, 1829,
Syst. der Akalephen, p. 23.—MERTENS, 1833, Mém. Acad. Sci. St. Péters-
bourg, sér. 6, tome 2, p. 492.—MiLNE-Epwarps, 1857, Annal. des Sci, Natur-
elles, Zool., sér. 4, tome 7, p. 291.—FoL, 1869, Anatomie und Entwick. der
Rippenquallen, p. 8—BIcELow, 1904, Bull. Museum Comp. Zool. at Harvard

College, vol. 39, p. 267.
Cestus, CHUN, 1880, Ctenophoren des Golfes von Neapel, p. 301.—VANHOFFEN,

1906, Nordisches Plankton, Ctenophoren, x1, p. 6.
GENERIC CHARACTERS.
Cestide in which the great extension of the sides in the stomodzal
axis and the marked compression of the body in the tentacular axis
cause the animal to assume the shape of a long, flat ribbon. The 4 inter-

44 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

radial canals arise directly from the funnel. The 4 meridional subventral
vessels are very long and extend around the aboral side of the narrow
edge of the body. The 4 meridional subtentacular canals each give
rise to a short tract of cilia and then bend downward and outward along
the middle of the sides of the animal and join with the meridional sub-
ventral canals and the oral forks of the paragastric canals at the extremi-
ties of the long sides of the animal. Each of the 2 median tentacles arises
from a deep sheath. The sexual products are developed only in the long
subventral canals. The larva passes through a Mertensia-like condition
in which the tentacular axis is longer than the stomodeal axis.

Species of Cestum are found in all the warmer oceans. The type
species is Cestum veneris Lesueur, of the Mediterranean and tropical
Atlantic. ‘“Cestum amphitritis” of Mertens, 1833, appears to be the
same species from the tropical Pacific.

Cestum veneris Lesueur. (Figs. 60 and 61, plate 12.)

Cestum veneris, LESUEUR, 1813, Nouv. Bulletin des Sciences de la Sociét. Phil.,
tome 3, p. 281, planche 5, fig. 1— Lresson, 1836, Annales des Sci. Nat., sér. 2,
tome 5, p. 245.—Fot, 1869, Beitrag Anat. Entwick. Rippenquallen, Berlin,
p. 8, Tafin. 2-4.

‘Cestus veneris, CHUN, 1880, Ctenophoren des Golfes von Neapel, pp. 53, 135, 152,
181, 301, Taf. 11-13 (full list of literature) —ALLMAN, 1881, Journal Linnean
Soc., London, vol. 16, p. 106.—CuHuNn, 1898, Ctenophoren des Plankton-Exped.,
p. 20.—GRAEFFE, 1884, Arbeit. Zool. Inst. Wien, Bd. 5, p. 362.—-WaAGNER,
N., 1885, Die Wirbellosen des Weissen Meeres, p. 54.—R6MER, 1903, Fauna
Arctica, Ctenophoren, Bd. 3, p. 85.—VANHOFFEN 1906, Nordisches-Plankton,
Ctenophoren, 11, p. 6, Fign. 14, 15.—Samassa, 1892, Archiv fiir mikroskop.
Anatomie, Bd. 40, pe. 169, 218 (histology)—MoseEr, 1908, Abhandl. Akad.
Mitinchen, Suppl. Bd. 1, Abhandl. 4, p. 12.

Cestum amphitrites, MERTENS, 1833, Mém. Acad. Sci. St. Pétersbourg, Sci. Math.
Phys. et Nat., sér. 6, tome 2, E 492, Taf. 1 (tropical Pacific).

‘Cestus pectenalis, BiGELoW, 1904, Bull. Museum Comp. Zool. at Harvard College,
vol. 39, p. 267, plate 8, fig. 30 (Indian Ocean).

The animal is flat and ribbon-shaped, being about 80 mm. high and
sometimes over 1,500 mm. wide, although specimens over 800 mm. in
width are not common. The body is strongly compressed in the ten-
tacular diameter. The apical sense-organ is a simple capsule containing
a cluster of concretions, and is slightly depressed beneath the general
level of the body surface. The long, narrow aboral side of the animal
is arched and bears small, wart-like protuberances. The ventral, ten-
tacle-bearing edge is much narrower than the aboral edge, and the sides
bulge slightly outward so that the animal is widest midway between
mouth and apex. The subtentacular rows of combs are represented by
4 short tracts close to the sides of the sense-organ. Beyond these there
is a short, free interval, and then commence the 4 long subventral rows
of combs which extend along the sides of the arched aboral edge of the
animal. Simple tentacles, closely set in a double row, extend along
the sides of the oral edge of the animal, following the courses of the oral
branches of the paragastric canals.

The stomodzum is cruciform in cross-section, being slightly out-
folded in the tentacular (funnel) axis, although wider in the sagittal
axis. The funnel is about one-third to one-fourth as long as the height
of the animal, becoming relatively shorter as the animal increases in
size. The 4 slender, interradial canals arise from the funnel, as do also,

PLaTE 11.
Eurhamphea vexilligera.

Fic. 57. Enlarged view of auricular side of animal. Tortugas.
Florida, May 15, 1906.

Fic. 58. Specimen about 1.75 times natural size. Side view facing
oral lobes.

Fic. 59. Part of one of the combs of cilia, showing excretion pores
between combs and papillate surface of genital organs.

Drawn from life, by the author.

PLATE IL.

CTENOPHORES OF THE ATLANTIC COAST oF NorTH AMERICA

oe be “Fre TRS The ks ETE

B.Meisel ith. Boston

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 45

at a lower level, the 2 paragastric and 2 tentacular vessels. All of these
canals are of slender caliber.

The 4 interradial vessels (7, fig. 61, plate 12) fork near their aboral
ends, and give rise to 8 adradial vessels (ad, fig. 61, plate 12). The adra-
dial canals leading to the meridional subventral vessels are relatively
long, but those leading to the meridional subtentacular vessels are
very short. The subtentacular vessels, st, give rise to 4 short rows
of combs and also extend outward and downward (oral-ward) beyond
their points of origin, and then bend inward and finally outward along
the middle of the broad sides of the body and at last join with the 4
meridional subventral canals at the middle of the tips of the ribbon-
like body. The oral forks of the paragastric canals also fuse with the
meridional canals at this point, and in their course along the almost
knife-edged oral side of the body one finds numerous, simple tentacles.
The oral forks of one side of the body do not connect with those of the
opposite side, and there is no ring-canal around the mouth. There are
neither tentacles nor combs upon the narrow, lateral ends of the body.
The 2 rudimentary, axial tentacles are each set within a deep sheath in
the side of the body close to the side of the paragastric canals.

The sexual products are developed throughout the entire lengths
of the 4 meridional subventral canals under the combs of cilia.

The young animal is transparent, but when old it often becomes
violet with a beautiful greenish-blue or ultra-marine fluorescence (see
‘Chun, 1880, Ctenophoren des Golfes von Neapel, p. 152).

The embryonic development has been well described by Chun,
1880, pp. 135-141. The larva passes through a Mertensia-like stage
wherein the tentacular diameter is longer than the stomodeal axis, al-
though as growth proceeds the stomodzal axis becomes so enormously
extended that the body is reduced to the shape of a flat ribbon. While
in the Mertensia stage there are about 4 ciliated plates on each of the
meridional subventral and 1 ciliated plate on each meridional subten-
tacular canal. The meridional canals and the paragastric canals at first
end blindly, but their free ends extend outward and downward and finally
fuse with the oral forks of the paragastric vessels. The larva is strik-
ingly like the Cydippide and shows the evident derivation of Cestum
from this order, but the general plan of the canal-system resembles that
of the immature Beroide, in the separation of the peripheral canal sys-
tems of the two sides of the body although in the mature Beroide a
circum-oral canal develops in some species, and all of the meridional
vessels become connected by a network of fused lateral branches.

Cestum veneris is abundant in the Mediterranean and is also found
in the tropical Atlantic. At Tortugas, Florida, it is not often met with,
but can not be called rare. The so-called Cestum amphitrites Mertens,
of the tropical Pacific, appears to be identical with the Atlantic and
Mediterranean C. veneris, and Bigelow, 1904, appears to have described
this form from the Maldive Islands, Indian Ocean, under the name
Cestum pectenalis. Wagner, 1885, records the capture of Cestum veneris
in the White Sea and this is the most northerly locality from which this
‘Ctenophore has been reported. It was probably swept northward along
the Norwegian coast in the Gulf Stream drift.

46 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

In the Pacific Cestum the lateral ends of the long body bear yellow
pigment, according to the figure by Mertens, 1833, and the description
and figure by Bigelow, 1904. This has not been observed in the Atlantic
or Mediterranean Cestum, but it occurs in the closely allied Folia from
Tortugas. The coloration may be due to the presence of commensal
plant-cells.

Genus FOLIA (nom. nov.)
Vexillum, preoccupied by Botten for Mollusca in 1798.

Vexillum, Fo, 1869, Anat. und Entwick. der Rippenquallen, Berlin, p. 6—Cuun,
1880, Ctenophoren des Golfes von Neapel, pp. 300, 302.

GENERIC CHARACTERS.

Cestide with body elongated in the stomodeal axis, as in Cestum,
but with the aboral narrow edge flat, not arched, as in Cestum. The 4
subtentacular meridional tubes do not bend outward and inward from
their points of origin from the 4 adradial vessels as in Cestum, but pro-
ceed straight outward along the middle of the broad sides of the animal.

The type species and only known form is Folia parallela of the Medi-
terranean and tropical Atlantic.

The genus is closely allied to Cestum, but is at once distinguished
by its straight, subtentacular canals, whereas those of Cestum curve where
they arise from the axial canal-system.

Unfortunately we can not retain the generic name Vexillum, for
it was preoccupied for Mollusca by Bolten, 1798, in Catalogus Museum
Boltenanum, Pars Secunda, p. 138, and this name is accepted by Her-
mannsen, 1847, in Indicis generum malacoz., vol. 2. I therefore propose
the name Folia, in honor of Professor Fol, who discovered this cteno-
phore among the Canary Islands.

Folia parallela. (Figs. 62 to 65, plates 13 and 14.)
Vexillum parallelum, Fou, 1869, Anat. und Entwick. der Rippenquallen, Berlin,

p. 6, Taf. 2, Fign. 1-5 —Cuuwn, 1880, Ctenophoren des Ifes von Neapel,

p. 303, Taf. 11, Fign. 4-6, Taf. 13, Fign. 14-17; 1898, Ctenophoren der Plank-

ton-Expedition, p. 21.—MoseEr, 1908, Abhandl. ‘Akad. Minchen, Suppl. Bd.

1, Abhandl. 4, p. 15.

This species is smaller than Cestum veneris, being only about 15 mm.
high and 150 mm. wide. The aboral edge is nearly flat, not arched as
in Cestum. The stomodeum is shorter than in Cestum, being not half
as long as the height (oral-aboral axis) of the animal. Above all the 4
subtentacular meridional tubes proceed straight outward along the middle
of the broad sides of the animal from their points of origin at the ends of
the 4 rudimentary adradial canals to the edge of the outermost sides
of the animal, where they join the 4 subventral canals. The separation
between the subtentacular and subventral rows of combs is not so wide
as in Cestum, being hardly perceptible in some specimens. The tentacle-
bulb and its sheath are smaller than in Cestum. In the Mediterranean
the Folia is colorless, but at Tortugas, Florida, some of the specimens
(not all) show faint yellow in the gelatinous substance of the aboral
sides of the extended ends of the animal. This yellow color may, how-
ever, be due to the presence of commensal plant cells. Fol described
this ctenophore from the Canary Islands, and Chun found it in the Medi-

PLATE 12.

Fic. 60. Center of a young Cestum veneris, 84 mm. long. Tortugas,
Florida, May 25, 1907.

Fic. 61. Center of a mature Cestum veneris. Tortugas, Florida,
July 4, 1907. ad, adradial vessels; 7, funnel; 7#, axial
funnel-tube; g, paragastric canals; 7, interradial canals;
mu, muscle fibers; st, subtentacular meridional canals;
sto, stomodzeum; sv, subventral meridional canals; 2,
tentacular canals; ten, tentacle-bulb; ts, opening of ten-
tacle-sheath.

Drawn from life, by the author.

CTENOPHORES OF THE ATLANTIG COAST OF NORTH AMERICA

PLATE 12.

Mil
Weide wae ae iD Ri Z
TTT vie |

mu ad’

B.Meisel lith Bostoa

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 47

terranean, and it is evidently distributed entirely across the tropical
Atlantic, being fairly common at times at Tortugas, Florida.

The animal moves by vermiform contractions, aided by its combs
of cilia, and advances with remarkable rapidity by a series of sudden
darts with intervals of rest between. I have seen a perfect specimen of
this ctenophore which was swimming normally in an aquarium suddenly
tear itself into shreds through muscular contraction.

Order BEROIDZ Eschscholtz, 1820.

Beroide, EscHscHoLtz, 1829, Syst. der Acal., p. 35.-GEGENBAUR, 1856, Archiv
fiir Naturgesch., Jahrg. 22, p. 192.—Acassiz, A., 1865, North Amer. Acal.,

Pp. 35.—CuHuN, 1880, Ctenophoren des Golfes von Neapel, p. 303. — Moser,

1903, Ctenophoren der Siboga-Exped., p. 19.—VANHOFFEN, 1906, Nordisches

Plankton, Ctenophoren, p. 7.— ROMER, 1903, Fauna Arctica, Ctenophoren,

Bd. 3, p. 81.— BENHAM, 1907, Trans. New Zealand Institute, vol. 39, p. 139.

Agassiz regarded the Beroide as the simplest of the ctenophore
and considered that the more complexly organized Lobate, Cydippide,
and Cestide were derived from them. They are simple in that they lack
tentacles and tentacular canals. The structure of the apical sense-
organ and the papille of the pole-plate are, however, more complex than
in other orders of ctenophore. Chun, 1880 (pp. 267, 271), contrary to
Agassiz, regards the Beroidez as the most highly differentiated of cteno-
phore and considers that they have remotely descended from tentac-
ulate forms, and that they can not be regarded as the ancestral type from
which the existing tentaculate ctenophore have been derived.

The loss of the tentacles in the Berodia may have come about,
according to Chun, through the powerful development of the cilia, giving
freedom and rapidity of motion, and through the great development of
the wide-flaring mouth which enables the animal to obtain food without
depending upon tentacles to capture prey. It is remarkable, however,
that no trace of tentacles or tentacular vessels appears in the larve of
Beroide, but we must remember that in the genus Ocyropsis of the
Lobatz there are neither tentacles nor tentacular vessels, so that the case
of the Beroide does not stand alone and need give us no great concern.
Moreover, in essential respects the fusions between the oral branches of
the paragastric and the meridional canals are similar in Cestide and
Beroide excepting that in the Beroide an anastomosing network may
connect some or all of the meridional canals one with another.

The lateral diverticula of the meridional and oral branches of the
paragastric canals, which are seen only in the Beroidz, are evidently,
phylogenetically speaking, of recent origin, for they appear very late in
ontogeny in Beroé.

It is probable that the Beroidze and Cestidz are derived from a com-
mon stock whose relationship to the Lobatz was close.

The lateral compression in the funnel-axis is more marked in the
Beroidz than in any other order of ctenophores excepting the Cestide.

There are 2 genera, Beroé in which the aboral pole of the animal is
dome-like and oval, and Nets Lesson, in which there are 2 prominent
lobes on both sides of the apical sense-organ. (See von Lendenfeld,
1885, Zeit. far wissen. Zool., Bd. 41, p. 673.)

48 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

Genus BEROE Browne, 1756.

Beroé, BRowneE, 1756, Civil and Nat. Hist. Jamaica, p. 384; also, edition 2, 1789.—
Fasricius, 1780, Fauna Grénlandica, p. 361.—CuuN, 1880, Ctenophoren des
Golfes von Neapel, p. 306.—Acassiz and Mayer, 1899, Bull. Museum Comp.
Zool. at Harvard College, vol. 32, p. 177.—MosEr, 1903, Ctenophoren der
Siboga-Exped., p. 20.—BENHAM, 1907, Trans. New Zealand Institute, vol.
39, P. 139-—MosEr, 1908, Abhandl. Akad. Miinchen, Suppl. Bd. 1, Abhandl.
4, p. 18, 1907; Ctenophoren der deutsche Siidpolar-Exped., Bd. 11, Zool. 3,
p- 153.—Maas, 1908, Méduses Exped. Antarctique Frangaise, p. 15.

Idyia, FREMINVILLE, 1809, Nouv. Bull. Soc. Philomat., p. 329.

Beroé, Medea, Pandora, EscuHscHoutTz, 1829, Syst. der Acal., pp. 35, 39-

Idya, Cydalisia, LEsson, 1843, Hist. Zooph. Acal., p. 67.

Rangia, Idyia, Idyiopsis, Acassiz, L., 1860, Cont. Nat. Hist. U. S., vol. 3, pp. 191,
270, 288, 296.

Pandora, Moses, 1908, Abhandl. Akad. Miinchen, Suppl. Bd. 1, Abhandl. 4, p. 32,
1909; Ctenophoren der deutsche Stidpolar-Exped., Bd. 11, Zool. 3, p. 159.

Pandora, preoccupied for Mollusca by BRuGUIERE, 1791.

GENERIC CHARACTERS.

Body miter-shaped, egg-shaped, or conical; extended laterally in
the stomodzal axis. Mouth opening wide and ectodermal portion of
stomach (stomodeum) voluminous. The polar-plate surrounding the
sense-organ at the aboral pole is fringed with a row of branched papille.
There are neither tentacles nor tentacular vessels. There are ciliated
areas upon the walls of the stomodeum near the mouth. The axial
funnel-tube which extends upward to the sense-organ, is deeply cleft so
that 2 lateral vessels extend upward to the 2 apical excretion-pores on
the sides of the pole-plate. 8 meridional vessels and 2 paragastric canals.
The meridional vessels lie under the 8 rows of ciliary combs; the 2 para-
gastric vessels extend down the middle of the broad sides of the animal
and branch out in a J-like manner near the mouth, and fuse with the
meridional canals of that side only, but in B. ovata the 8 meridional
canals may be placed in communication one with another by means of
an anastomosing network of side branches, thus establishing a circum
oral canal-system. L. Agassiz and Chun state that these anastomosing
vessels do not cross the narrow sides of the body, thus leaving the 4
meridional vessels of one broad side separated from those of the other
broad side; but I find that while this is true of the young, in mature
specimens of B. ovata from Tortugas all 8 of the meridional vessels are
connected by the network, which extends across the narrow sides of the
animal. In B. cucumis, however, the side-branches do not anastomose,
so that Agassiz’s statement is true for this species only.

The type species is Beroé ovata of the Mediterranean, Atlantic, and
Pacific.

In Beroé ovata the side branches from the 2 oral vessels and from the
8 meridional canals are deep-lying and anastomose, fusing to some extent
with the 2 paragastric canals. In B. cucumis, however, these fusions do
not take place and the branches do not anastomose, and the side branches
are nearer the surface than in B. ovata.

It has been pointed out by Chun that about 45 species of Beroide
have been described under 8 generic names, the genera being based
mainly on coloration and on external form of the body. Chun, however,
came to the conclusion that all of these forms fall into one genus Beroé.
The great diversity of opinion among older authors came from a failure

PLATE 13.

Fic. 62. Folia parallela. Natural size. Tortugas, Florida, May 9,
1906.

Drawn from life, by the author.

PLate 13.

CTENOPHORES OF THE ATLANTIG Coast oF NortH AMERICA

B.Meisel lith. Boston.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 49

to study the internal structure of the animals. They also placed too much
teliance on external shape, which is not only very variable but is also
greatly modified by temporary contractions of the muscles. The color in
Beroé also changes with age, the very young animals being spotted, after-
wards almost transparent, and finally, when mature, more or less diffusely
pigmented. Also specimens from cold waters are apt to be pink, while
those from the tropics are apt to be dull, translucent, and milky in hue.

B. ovata and B. jorskali are known from the Mediterranean, and they
tange widely over the tropical Atlantic and Pacific. B.cucumis is found
in the Arctic and Antarctic regions and according to Moser also in the
Atlantic, Pacific, and Indian oceans, being cosmopolitan in its wide range.

Pandora of Eschscholtz and Moser is, I believe, only a common
aberration or growth-stage of Beroé in which the 4 subventral rows of
combs are longer than the others. Every large swarm of Beroé ovata
along our coast contains some half-grown individuals in this stage, but
I have never observed this condition in fully-grown animals. The gen-
eric name Pandora is preoccupied and can not be applied to ctenophores.

Kinoshita, 1910, Centralblatt Physiol., Bd. 24, p. 726, finds that in
Beroé and Leucothea the combs are brought to a stand-still by mechanical
stimulation of the oral pole, or of the oral-ward part of a section of the
animal; and conversely a stimulation of the aboral pole of a quiet animal
sets its cilia into movement, a result which would not follow if we stimu-
lated the oral pole. Stimulation increases the rapidity of the waves
that course down the rows of combs.

Beroé ovata Chamisso and Eysenhardt. (Figs. 66, 68 to 75; plates 14 to 16.)

Beroé, BRowNE, 1756, The Civil and Natural History of Jamaica, p. 384, Table

43, fig. 2; also, Second edition, 1789.
?) Beroé albens, ForsKAu, 1775, Descrip. animal, p. 111.
edusa infundibulum, TuRTON, 1806, Linné’s Sys. Nature, vol. 4, Worms, p. 121.

Beroé ovata, B. capensis, B. punctata, CHAMIsso et EYSENHARDT, 1821, Nova Acta
Acad. Leop. Car., tome 10, pp. 360, 361, Tab. 31.

Beroé ovata, B. punctata, EscHscHoLtz, 1829, Syst. der Acalephen, pp. 36, 37.

Idya _ mertensti, MERTENS, 1833, Mém. Acad. Sci., St. Pétersbourg, Sci. Math.
Phys. et Nat., sér. 6, tome 2, p. 536, Taf. 13, Fign. 1-4.

Idyiopsis clarkit, Acassiz, L., 1860, Cont. Nat. Hist. U.S., vol. 3, pp. 288, 296; figs.
1o1, 102.—Acassiz, A., 1865, North American Acalephe, p. 39, figs. 63, 64.

Idyiopsis affinis, Acassiz, L., 1860, Cont. Nat. Hist. U. S., vol. 3, pp. 288, 296.

Beroé punctata, McCavy, 1859, Proc. Elliott, Soc. Nat. Hist., Charleston, vol. 1, p.254.

Beroé ovata, Cun, 1880, Ctenophoren des Golfes von Neapel, p. 308, Taf. 14, Fign.
I, 2; 1898, Plankton-Expedition, Ctenophoren, p. 26.

Beroé clarkit, MAYER, 1900, Bull. Mus. Comp. Zool. at Harvard College, vol. 37, p. 82.

Beroé ovata, ALLMAN, 1862, Proc. Royal Soc. Edinburgh, vol. 4, p. 519; also,
1882, Jour. Linnean Soc. London, vol. 16, p. 89 (development)—KRuKEN-
BERG, 1880, Vergleichend. physiolog. Studien zu Tunis, etc., pp. 1-22.—
GRaEFFE, 1884, Arbeit. Zool. Inst. Wien, Bd. 5, p. 362 (occurrence at Trieste).—
VERWORN, 1891. Pfltiger’s Archiv. ftir ges. Physiol., Bd. 50, p. 423, Fign.
1-5 (functions of the apical sense-organ).—NacGEL, 1893, Pfltiger’s Archiv
fir Physiol., Bd. 54, p. 165, Fign. 1-5 (physiology) —Drizscu and Morecan,
1895, Archiv fir Entwickelungsmech., Roux, Bd. 2, p. 204.— ZEIGLER, 1898,
Archiv fir Entwick.-Mech., Bd. 7, p. 34, Fign. 1-12.—RHUMBLER, 1899;
Ibid., Bd. 8, p. 187, 28 Fign. (segmentation). — R6mMErR, 1903, Fauna Arctica,
Ctenophoren, p. 84 (list of literature) —MoseEr, 1903, Ctenophoren der Siboga-
Expedition, p. 20 (list of literature). —Samassa, 1892, Archiv ftir mikroskop.
Anat., Bd. 40, p. 207, Taf. 8, 9 (histology).—Lojacono, 1908, Journ. Phys.
Path. Gen., Paris, tome 10, p. 1001 (the poison of Beroé).—MoseER, 1908,
Abhandl. Akad, Mtinchen, Suppl. Bd. 1, Abhandl. 4, p. 22.

Beroé shakespeari, BENHAM, 1907, Trans. New Zeal. Institute, vol. 39, p. 139, pl. 7.

50 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

Body miter-shaped, 7o to 115 mm. long. Lateral compression very
marked, the broad, lateral diameter being fully 3 times as wide as the
narrow diameter. The apical sense-capsule lies near the surface at the
bottom of a shallow cleft; it contains a spherical mass of lithocyst cells,
and is flanked on two sides by a row of branched papille in the form of a
figure 8, the loops of the “8”’’ extending around the pole-plate in the
plane of the wide, lateral diameter. The 2 excretory pores open on the
alternate outer sides of the pole-plate. There are 8 rows of ciliated plates,
each row containing 25 to 30 combs of cilia. These extend about three-
quarters the distance from the apical sense-organ toward the mouth.
The mouth is a wide-gaping slit and its cavity is of large dimensions,
comprising the greater part of the center of the animal. The entodermal
part of the stomach is small. There is no axial funnel-tube, but instead
there are 2 lateral tubes which extend upward from the funnel to the 2
halves of the pole-plate. Each of these tubes opens by an excretion pore
on alternate opposite sides of the figure ‘‘8’’-shaped pole-plate. The
funnel, or entodermal part of the stomach, gives rise to 4 interradial tubes
which bifurcate, giving 8 adradial canals, which in turn lead to the 8
meridional vessels that extend down the sides of the body immediately
under the 8 rows of ciliary combs. In addition to these meridional tubes
there are two lateral paragastric tubes which arise from the funnel and
extend down the middle of the broad sides of the animal. The 4 merid-
ional canals of each broad side are placed in communication one with
another by means of the oral forks of the paragastric vessels which extend
along the broad side of the mouth, but do not fuse with their fellows on
the opposite side to form a ring-canal. The 8 meridional canals are,
however, placed in communication one with another by means of a loose
network of numerous side-branches which anastomose through the
gelatinous substance of the animal, forming a wide meshwork. Some of
these branches join the 2 lateral, paragastric tubes, although never to
the extent observed in B. forskali of the tropical Pacific. These fusions
occur only in well-grown individuals of Beroé ovata, and distinguish this
species from Beroé cucumis of our northern waters,where no anastomosing
of the side branches, or fusions with the paragastric vessels has been
observed. The young B. ovata can not be distinguished from B. cucumis.
There are numerous small, stellate areas of dark brown and light rosin-
colored spots upon the 8 meridional vessels and around the mouth. These
spots are especially conspicuous in young animals. The network of anas-
tomosing vessels that arises from the meridional canals is of a delicate
pink. The gelatinous substance of the mature animal is of a translucent,
steely-blue color. In Florida the animal is dull-milky in color, but in
the colder northern waters, as in the Chesapeake Bay, it is highly colored
and the canals deep pink or reddish-brown.

When 2.5 mm. long the animal is covered with large, stellate pig-
ment spots of a dark brown and rosin-yellow color. The apical sense-
capsule is relatively very large and is flanked by 4 branched, ciliated
papilla. The 8 rows of ciliated combs extend only about half the dis-
tance from the apical sense-organ toward the mouth. When about 15 to
20 mm. long the animal is quite translucent. The 8 meridional vessels

Fic

Fic

Fic

Fic

PLATE 14.

. 63. Folia parallela. Enlarged view of a young specimen 27
mm. long. Tortugas, Florida, May 29, 1906.

. 64. Center of a mature specimen of Folia parallela, about 150
mm. long. ad, adradial canal; f, funnel; ft, axial funnel-.
tube; 7, interradial canals; st, subtentacular vessel; sto,
stomodzum; sv, subventral vessel.

. 65. End of one side of body of specimen whose center is shown
in figure 64. One sees the confluence between the sub-
ventral and subtentacular vessels and oral forks of the
paragastric canals.

. 66. Beroé ovata. Young Ctenophore, 2 mm. high. Cayo Con-.
fites, Northern Coast of Cuba, February, 1892.

Drawn from life, by the author.

PLATE 14.

CTENOPHORES OF THE ATLANTIG Coast OF NorTH AMERICA

BEES.

SSBuege ~~
Bes wag Th

la

5 CL Vaan Ae

a A a Na ey ee

D See =

iA ae EEe.
ee pee

ia Me ee

i oy eas is

yw

Say

Sess

Ss
PS

oes

“oe

p=
pager:

B.Meisel tith. Boston.

PLATE 15.

Fic. 67. Beroé cucumis. 29 mm. long. Eastport, Maine, August
14, 1897.

Fic. 68. Beroz ovata. Natural size. St. Mary’s River, Maryland,
November 11, 1905.

Fic. 69. Beroé ovata. View looking down upon aboral pole of spec--
imen represented in figure 68, to show lateral compression
of funnel-axis.

Fics. 70 and 71. Larval stages of Beroé. Newport, Rhode Island,
July, 1892, Agassiz Laboratory.

Drawn from life, by the author.

Piate 15.

GYENOPHORES OF THE ATLANTIC Coast oF Nort AMERICA

wd
eS

Doe Leb

CYRREIKI

x
nti
a

Is

7

Aa

ay,
7)

Sen

ai

B.Meisel {ith. Boston.

69

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 51

begin to give rise to lateral branches, and the papille flanking the apical
pole-plate have greatly increased in number. The steel-blue color of
the gelatinous substance and the pink of the meridional vessels begin
to appear at a later stage.

When the young animal from Tortugas, Florida, is 26 mm. long,
and 18 mm. wide in the broad, and 7 wide in the narrow axis of the body,
the oral forks of each head side of the body remain separate, and do not
fuse across the narrow sides. The two broad sides are, however, con-
nected one with another by an anastomosing network from the 4 meri-
dional canals which flank the 2 narrow sides of the body. Hence the
network of the narrow sides anastomoses and forms a complete circum-
oral circuit before any anastomosing is seen on the broad sides of the
animal. In this young animal there are as yet no fusions between the
network and the 2 paragastric canals. The animal is now decidedly
pink in color.

Beroé ovata is abundant among the West Indies and along the coast
of the United States as far north as Chesapeake Bay. This species is,
I believe, identical with the Mediterranean form, although the Florida
specimens are not so intensely pink as the Mediterranean ctenophore.

Beroé shakespeart Benham, from New Zealand, is, I believe, identical
with B. ovata, for it bears so close a resemblance to the form of B. ovata
from Florida that were the two found together one could not separate
them specifically.

Form, size, and color are practically worthless as specific criteria
in the genus Beroé.

Beroé ovata has been the subject of some interesting experimental
work. Driesch and Morgan, 1895, found that if the egg be cut in two
at the 2-cell stage, each blastomere gives rise to a half embryo, which,
however, has 3 entodermal cells instead of 2, as one would expect. Only
4 tows of cilia are developed. Hence each blastomere segments almost
as if still a part of the whole egg. The same statement is true of the one-
fourth blastomere obtained by separating the blastomeres of the 4-cell
stage, for each develops into a one-fourth larva with, however, 2 ento-
derm cells intead of 1. It will be recalled that Chun, 1892 (Festschrift
far Leuckart, pp. 77-108), showed that an isolated blastomere of the
2-cell stage in Bolinopsis produces a half-larva.

Driesch and Morgan cut in two eggs of B. ovata which had been
fertilized but had not yet segmented, and the part containing the nucleus
divided in general like that of an isolated blastomere, giving rise to a
partial embryo. Hence the incomplete development is due to the proto-
plasm, not to the nucleus.

Fischel, 1897 (Archiv Entwickelungsmechanik, Roux, Bd. 6, p. 109,
Taf. 6), has continued these studies of Driesch and Morgan. He finds
that if we isolate the blastomeres of B. ovata in the first, second, and
third cleavages, larve develop with 4, 2, and 1 row of combs, respec-
tively. Fischel also found that if we remove some of the blastomeres at
any segmentation stage, partial larve result, which are the more nearly
complete the smaller the removed part. Hence the result is the same
whether the nucleus has divided or not, the nucleus manifesting no

52 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

power to induce a process of regeneration whereby the complete form
might be restored. One should consult a review of the work of Driesch
and Morgan by Roux, 1895 (Roux’s Archiv fir Entwickelungsmechanik
Bd. 2, p. 448), and also by Chun in the same volume (p. 444), who main-
tains that the missing parts of these partial embryos will in time regen-
erate. Probably every one who has studied living ctenophores will agree
that, while their healing power is remarkable, they appear to have little
power to regenerate lost parts.

Verworn, 1891, finds that the concretions of the sense-organ in
B. ovata are not organs of hearing, but serve to maintain the equilibrium
and normal position of the body in the water, and should thus be called
statoliths. (See also Engelmann, 1887, Zool. Anzeig., Jahrg. 10, p. 439.)
\ The histology of B. ovata is dealt with at length by R. Hertwig, 1880
(Jena. Zeit. fur Naturw., Bd. 14, pp. 316-457); and by Samassa, 1892
(Archiv mikroskop. Anat., Bd. 40, pp. 159, 207).

Beroé cucumis Fabricius. (Fig. 67, plate 15; fig. 76, plate 17.)

Beroé cucumis, Fazsricius, 1780, Fauna Grénlandica, No. 353, p. 361.—EscuH-
SCHOLTZ, 1829, Syst. der Acalephen, p. 36.—Sars, M., 1835, Beskriv. og. Jagt-
tageker., p. 30, Tab. 6, Fign. 15a-d—Morcu, 1857, Beskriv. af. Grénland.,
p. 98.—VANHOFFEN, 1895, Bibliotheca Zoologica, Heft 20, Lig. 1, pp. 16. 20,
21.—CuHuN, 1898, Ctenophoren der Plankton Expedition, p. 26.—R6MER,
1903, Fauna Arctica, Ctenophoren, Bd. 3, p. 81 (full list of literature).—
MOSER, 1903, Ctenophoren der Szboga-Expedition, p. 21.—VANHOFFEN, 1906,
Nordisches Plankton, Ctenophoren, 11, p. 7, Fign. 16, 17.— BROWNE, 1905, Proc.
Royal Soc. Edinburgh, p. 785.—MoseEr, 1908, Abhandl. Akad., Mtiinchen, Suppl.
Bd. 1, Abhandl. 4, p. 23; also, Zool. Anzeiger, Bd. 33, p. 756, 1908, Revue
Suisse de Zool., tome 16, p. 10 (from Amboina); also, 1909, Ctenophoren der
deutsch. Stidpolar-Exped., Bd. 11, Zool. 3, pp. 154, 167, 189.

Idya cucumis, I. borealis, Medea fulgens, M. arctica, Lesson, 1843, Hist. Zooph.
Acal., pp. 133, 134, 136.

Idyia roseola, Acassiz, l., 1860, Cont. Nat. Hist. U. S., vol. 3, pp. 270, 296, plates
1, 2—Packarp, A. S., 1863, Canadian Nat. and Geol., vol. 8—Acassiz,
A., 1865, North Amer. Acal., p. 36, figs. 52-62; 1874, Mem. American Acad.,
vol. 10, No. 3, p. 362, plates 1, 2; plate 3, figs. 1-24.—FEWKEs, 1884, Mem.
a Comp. Zool. at Harvard College, vol. 9, No. 3, figs. 1-7, 10-13, 46, 48-50,
pl. rx.

Beroé roseola, LEIDY, 1890, Proc. Acad. Nat. Sci. Philadelphia, p. 341.

This species attains a length of 60 to roo mm. It is miter-shaped
and the lateral compression is very marked, the broad lateral diameter
being fully twice the width of the narrow. The 8 rows of cilia extend
about three-quarters the distance from the apical sense-organ to the
mouth and each is composed of about 100 combs. It is distinguished
from Beroé ovata by the fact that the peripheral network does not anas-
tomose and that none of these vessels join the two lateral paragastric
canals. There is no ring-canal around the mouth, and the peripheral canal
systems of the two broad sides are separated one from another. The
intense pink color of the stellate pigment-cells of the meridional vessels
and of the circumoral canal is also deeper than in B. ovata.

This species is abundant along the coast of New England and attains
a very large size in Halifax Harbor, Nova Scotia, in September. It
extends along the coast of Greenland, and is common in the Labrador
current. It is circumpolar in distribution, is abundant in the North
Sea and off the coast of Scotland, and is identical with “Idyia cyathina”’

ee

PLATE 16.
Beroé ovata.

Fic. 72. Immature, 30 mm. high, Willoughby Harbor, Hampton
Roads, Virginia, October 31, 1904. Lateral diverticula
from the meridional vessels close to outer surface; they
occasionally anastomose but do not join with paragastric
vessels. Yellow color apparently due to parasitic plant
cells,

Fic. 73. Mature, 1.5 times natural size. Key West, Florida, June
7, 1897.

Fic. 74. Young stage, showing an aberration quite often observed
in the young wherein the subtentacular rows of combs
are shorter than the subventral. Charleston Harbor,
South Carolina, September 7, 1897.

Fic. 75. Aboral pole of the ctenophore shown in figure 74. ad,
adradial canal; f, funnel; fs, the two lateral funnel-tubes;
g, paragastric vessel; 7, interradial canal; st, subtentacu-
lar canal and row of combs; sv, subventral canal.

PLATE 16.

CTENOPHORES OF THE ATLANTIG Coast oF NorTH AMERICA

ee Kp

ue cA

B.Meisel {ith Boston.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 53

A. Agassiz, from the Pacific coast of North America. Moser, 1908, 1909,
records it from the eastern coast of Japan and also from the Antarctic,
Pacific, and Indian oceans.

In September, 1910, I visited Newfoundland in order to examine a
-sufficiently large number of B. cucumis to be assured that it is actually
specifically distinct from B. ovata. No differences can be detected in the
immature individuals of both species. When mature, however, some of
the side branches from the meridional vessels join with the paragastric

Fic. 12.—Young Beroé cucumis 19 mm. long. From life by the author. Hali-
fax, Nova Scotia, September 27, 1910. Peripheral canal-systems of two broad
sides are separated one from the other, and there is noring-canal around mouth.
The canal-system is in a stage characteristic of the adult Cestide.

canalsin B. ovata, but this does not occur in B. cucumis. Moreover the
side-branches anastomose in B. ovata, but in B. cucumis they remain
separate one from another (see fig. 76, plate 17.) In B. forskali of the
Mediterranean, Pacific, and Antarctic oceans, the fusions between the side
branches and the paragastric canals are more frequent than in B. ovata,
but I am not sure that the difference is actually a specific one, for it
may be of an intergrading character.

54 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA

Moser, 1903 (Ctenophoren der Siboga-Expedition, pp. 23, 24), has
described and figured two closely related varieties of Beroé, one of which,
B. pandora, she believes to be identical with Pandora flemingit Esch-
scholtz, 1829 (Syst. der Acalephen, p. 39, Taf. 2, Fig. 7). In both of
these forms the 4 subventral rows of combs are longer than the sub-
tentacular (she reverses the accepted usage of these terms in her de-
scription) instead of all 8 rows being of equal length. I doubt whether
this is a valid specific distinction, for I have noticed a certain intergrading
tendency of young individuals of B. ovata to have relatively short sub-
tentacular rows of combs. Such an individual obtained from a swarm
of normal B. ovata, with all 8 rows of equal length each to each, is shown
in fig. 74, plate 16. When full grown I believe the 8 rows are always.
practically equal in length each to each.

The differences between B. pandora and B. pandorino are of such
a character that I doubt their validity, bearing in mind the extreme
variation in shape of body exhibited by ctenophores of the genus Beroé.
Moser, 1908, redescribes this ctenophore from Japan under the name
Pandora flemingit (see Abhandl. Akad., Munchen, 1908, Suppl. Bd. 1,
Abhandl. 4, p. 32).

There appear to be but two dominant species of Beroé: B. cucumis
of cold water, and B. ovata of warm waters. B. forskali, B. pandora, etc.,
are probably only varieties of B. ovata.

The pink color of the stellate pigment cells of the meridional canals
does not appear until the young B. cucumis is about 25 mm. long, and
after the side branches have grown out from the sides of the meridional
vessels. When young the animal is transparent with a faint yellowish
tinge to the canal-system. The side branches do not begin to develop
until the animal is r9 mm. long. When about 23 mm. long it begins to
lose its transparency, and to assume the translucent milky hue of the
adult.

The young Beroé cucumis devours Pleurobrachia pileus with avidity.

At Halifax, Nova Scotia, in September when the harbor water
ranges from 13° to 15° C., B. cucumts is most active if heated to about
18° C., and dies at a temperature between 27.8° and 29.8°C. It would
seem therefore that B. cucumis could not survive in the surface waters
of the tropics.

PLATE 17.

Berée cucumis.

The

Drawn from life by the author.

60 mm. long. Halifax, Nova Scotia, Sep-

ex, excretory pores; g, paragastric canal.

imen,
side-branches do not anastomose.

Fic. 76. Mature speci
tember 28, 1910.

CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 55

Order PLATYCTENIDZ.

These are degenerate forms that have largely or wholly lost their
organs of locomotion. They are flat and expanded, the oral-aboral axis
being much shortened. They are sessile or creep slowly over sea-weeds.
In Celoplana and Ctenoplana the apical sense-organ is present, but in
Tjalfiella of Mortensen it appears to be absent. His specimens were,
however, preserved in formalin which may have destroyed the concre-
tions. There are two tentacles which are feathered in Ctenoplana and
Celoplana, but simple in Tjalfiella.

Mortensen’s discovery of cydippe-like young in the brood-sacs of
Tjalfiella proves that these forms are simply degenerate, and specialized,
not primitive ctenophores. After being set free in the Cydippe stage the
young swim about by means of their combs of cilia but soon settle down
and lose these organs of locomotion.

Tjalfiella tristoma Mortensen.

‘Tjalfiella tristoma, MoRTENSEN, 1910, Vidensk. Meddel fra den naturh. Foren. i

Kobenhavn, p. 249, Fig.

This is the most degenerate of the Platyctenide and is found attached
by its oral surface to stems of Umbellula lindahlii at depths from 240 to
290 fathoms in Umanak Fjord on the West Coast of Greenland.

The animal is transparent with yellow tentacle-bulbs, and is about
to to 15 mm. long, flat, laterally compressed with the oral surface
attached to the Umbellula, and with an erect, funnel-like tower-shaped
projection at each end of the body. A slight projection at the middle
of the flattened upper side of the animal may represent the degenerated
remnant of an apical sense-organ, but there appear to be no lithocysts.
A minute pore opens at this place. There are no combs of cilia.

The mouth is at the center of the surface of attachment and gains
access to the outer world by means of a median ventral furrow in the
tentacular plane. This furrow extends upwards along the sides of the
body to the two tentacle bulbs which are set within it at the sides of the
funnel-shaped tentacle sheaths. The tentacles have no side branches
thus differing from those of Ctenoplana, and Celoplana. The tentacles
are provided with colloblasts. There are 4 pairs of knob-like projections
on the upper surface of the animal and these mark the position of the
‘sexual organs each consisting of an ovary and a testis which open to
the outer world through an ectodermal invagination, as in Ctenoplana.

These genital cavities contain embryos which have ciliated combs
and are in the cydippe stage, thus proving that the Platyctenide are
degenerate and not primitive ctenophores. When about to leave the
parent animal a deep furrow develops in the tentacular plane along the
oral side of each young ctenophore. The young go through a free-
swimming stage before they settle down.

The canal-system of the adult is branched quite complexly.

Mortensen’s final paper upon this animal will appear in the Report
upon the Ctenophore of the Danish Ingolf-Expedition, vol. 5, part 2.

INDEX.

Important references are in italics, synonyms and unimportant references are in roman type.

Alcinoé, 26, 34
rosea, 26
vermicularis, 21
vermiculata, 26

Anais, 20

Anatomy, 2 to 5.

Beroé, 48
albens, 49
capensis, 49
clarkii, 49
cucumts, 52
globigereux, 10
octoptera, 9
ovata, 49
pandorino, 54
pileus, 10
punctata, 49
roseola, 52
shakespeari, 49
Beroide 6, 47
Bolina, 20
alata, 21
elegans, 24, 34
hydatina, 22, 25
littoralis, 33
norvegica, 21
septentrionalis, 21, 22
Bolinopsis, 20
infundibulum, 21
vitrea, 22

Callianiride, 18, 42
Calymma, 37
treviriani, 37, 40
Calymnide, 18
Cestide, 6, 42
Cestum, 43
amphitrites, 36, 44
pectenalis, 36, 44
veneris, 44
Cestus veneris, 44
Chaija, 34
Ciliary movement, nature of, 25, 26, 30
Ceoeloplana, 6, 55
Commensal plant cells, 36
Ctenophores feeding upon young cod, 7;
other ctenophores, 54; young scul-

pin, 9
Ctenoplana, 6, 55
Cydalisia, 48
Cydippe, 9, 14

cucullus, 8

densa, 15

hormiphora, 15

ovum, 8

pileus, ro

plumosa, 15
Cydippide, 5,8

Deiopea, 37, 40

Destructive contractions in Folia, 46

Development of: Beroide, 47, 50, 53, 543
Bolinopsis, 22; Cestum, 45; Eurham-
phza, 42; Leucothea, 35; Mnemiopsis,
28; Ocyropsis, 39; Pleurobrachia, 12;:
Tjalfiella, 55

Enemies of ctenophores, Beroé, 54; scypho-
medusz, 32

Eucharis, 34
multicornis, 35

Eurhamphea, 40
vexiligera, 40, 4I

Folia, 46
parallela, 46

Ganesha elegans, 5
Ganeshidae, 5
Geographical distribution, 1, 2

Habits of: Ctenophores, 6; Eurhamphea,.
42; Folia, 46; Pleurobranchia, 13; Leu-
cothea, 36; Mnemiopsis, 30; Tinerfe,.
17; Tjalfiella, 55

Heat reactions, 54

Hormiphora, 14

plumosa, 25
spatulata, 14
Idya, 48

borealis, 52
communis, 52
mertensii, 49
Idyia, 48
cyathina, 52
roseola, 52
Idyiopsis, 48
affiinis, 49
clarkii, 49

Lesueuria, 19
hyboptera, 19
vitrea, 19
Leucothea, 34
grandiformis, 36
multicornis, 35, 36
ochracea, 35
Lithocysts, structure of, 30
Lobate, 5, 18

Medea, 48

arctica, 52

fulgens, 52
Medusa infundibulum, 49
Mertensia, 8

cucullus, 8

ovum, 8

scoresbyi, 8

57

58 INDEX

Mnemia, 20, 26, 40
schweiggeri, 26
Mnemiide, 18
Mnemiopsis, 26
gardeni, 33
leidyi, 26
mecradyi, 31
Movements of muscles, effect of ions
upon, 26, 32
Muscular system, physiology of, 26

Neis, 47
Nervous system, histology of, 7, 23, 523
physiology of, 7, 30, 49

Obsolete generic names, 2
Ocyroé, 37
crystallina, 38
maculata, 40
tachee, 40
Ocyropsis, 37
crystallina, 38
fusca, 39
maculata, 40
‘Orders of Ctenophore, 5, 6

Pandora, 48, 49, 54
flemingii, 54
Parasitic actinian larvee in Mnemiopsis, 28
Partial larve, development of, 51
Phosphorescence of Mnemiopsis, 28
Physiology, 7, 25, 26, 30, 31, 32, 46, 49,
51, 52.

Platyctenida@, 6, 55
Pleurobrachia, 9
bachei, 10, 13
brunnea, 14
pileus, 10
rhododactyla, 10
Pleurobrachiide, 8
Poison of Beroé, 49
Eurhamphea? 42

Rangia, 48

Regeneration, 52

Relationship of: Beroide, to Cestide, 47;
Cydippide to Lobate, 18; Cydip-
pide to Platyctenide, 55

Sense of equilibrium, 30, 37, 52
Sex cells, ectodermal origin of, 14
Species, list of, 1
Stimuli, chemical, 7, 30, 32
electrical, 30
mechanical, 7, 49

Teeniate, 42

Tinerfe, 16
beehleri, 17
cyanea, 16
lactea, 17

Tjalfiella tristoma, 55

Ute, 16

Vexillum, 46
parallelum, 46
Volvox beroé, 21