a. Unattached forms; ventral cilia _Hypocomidæ_
present; one suctorial tentacle
b. Attached forms; thecate and _Urnulidæ_
athecate tentacles simple,
one or two in number
c. Thecate; posterior end of cup _Metacinetidæ_
drawn out into stalk; walls
perforated for exit of tentacles
d. Stalked or unstalked; globular; _Podophryidæ_
tentacles of different kinds, some (2 genera *_Ephelota_,
knobbed, others pointed *_Podophrya_)
e. Naked or thecate; stalked or not; _Acinetidæ_
tentacles numerous, usually
knobbed and all alike
f. Naked; athecate; tentacles _Dendrosomidæ_
numerous, all alike, knobbed and
grouped in tufts. They may be
simple or branched.
g. Sessile forms resting on basal _Dendrocometidæ_
surface or on a portion raised
like a stalk; tentacles many;
short and knobbed; distributed
on apical surface or localized
on branched arms
h. Stalked or sessile; tentacles _Ophryodendridæ_
long, rarely knobbed, supported
on proboscis-like processes
* Presence at Woods Hole indicated by asterisk.
Genus PODOPHRYA Ehr. '33.
(Bütschli '88; Stein '59; Perty '52; Cienkowsky '55; Quenn. '69;
Hertwig '77; Maupas '81.)
The body is globular, with tentacles radiating in all directions. The
tentacles may be very short or very long. The stalk also is either
short or long, and some species form stalks but rarely (_P. libera_).
The macronucleus is centrally placed and globular to ovoid in form.
The contractile vacuole is usually single. Reproduction takes
place by division; the distal half developing cilia and becoming a
swarm-spore. Fresh and salt water.
Podophrya gracilis, n. sp. Fig. 65.
Of all the _Podophrya_ that have been described not one approaches
this minute form in the relative length of the stalk. The body is
spherical and is covered with short capitate tentacles. The stalk is
extremely slender, bent, and without obvious structure. There are
one or two contractile vacuoles in the distal half of the body. The
nucleus is small and is situated near the insertion-point of the
stalk. Reproduction not observed. Diameter of body 8µ; length of
stalk 40µ. Only one specimen seen.
[Illustration: Fig. 65.--_Podophrya gracilis_.]
Genus EPHELOTA Str. Wright '78.
(Bütschli '88; Ishikawa '96; Sand '98.)
Small to medium-sized and large forms; colorless to brown. The body
is globular or oval or wedge-shape, sometimes quadrangular. The stalk
is variable, sometimes 1 mm. in length. The diameter of the stalk
increases from the point of attachment to the body of the animal;
it is usually striated either longitudinally or transversely, or
both. The tentacles are of two kinds and are usually confined to
the anterior half of the body. Some are long and sharp-pointed
and adapted for piercing; others are short, cylindrical, usually
retracted and capitate, adapted for sucking. Contractile vacuoles
vary from one to many. The macronucleus is nearly central in position
and usually of horseshoe shape, but is frequently branched and
irregular. Reproduction is accomplished by external multiple budding,
usually from the anterior half of the body. Salt water.
Ephelota coronata Str. Wright. Fig. 66.
Synonyms: _Hemiophrya gemmipara_ S. K.; _Podophrya gemmipara_
Hertwig.
The body is spheroidal, ovate, or pyriform, with numerous
sharp-pointed tentacles and a few straight, uniform tentacles. The
stalk is about three times the length of the body and tapers from its
widest part at the insertion in the body to the narrowest part at the
point of attachment. It may or may not be longitudinally striated.
This is one of the commonest of the _Suctoria_ found at Woods Hole.
It is usually present on Campanularian hydroids, but may be found on
algæ and Bryozoa.
Length of body 90µ to 200µ.
[Illustration: Fig. 66.--_Ephelota coronata_.]
Genus ACINETA Ehr. '33, Bütschli '88.
(Stein '54, '59; Claparède & Lachman '58; Quennerstedt '67; Hertwig
'76; Mereschowsky '79; Entz '84; Kent '81; Maupas '83; Gruber '84;
Gourret & Roeser '86, and others.)
Small to medium-sized forms. The distinguishing feature is that the
stalk is swollen at the distal extremity to form a cup or basin in
which the animal rests. The cup may be developed until the body is
nearly inclosed. The macronucleus is spherical or band form. The
contractile vacuole is usually single. Budding, so far as known, is
endogenous. Fresh and salt water.
Acineta divisa Fraipont '79. Fig. 67.
This extremely graceful form is common on Bryozoa at Woods Hole. The
cup is shaped like a wine glass and is specifically characterized by
a cup-formed membrane upon which the animal rests. The animal thus
has the appearance of being suspended on the edge of the cup. The
stalk is slender and about 4 times the length of the body. The
tentacles are all capitate and distributed, and about 2-1/2 times the
body length. They sway back and forth very slowly. The nucleus is
spherical and central in position. The contractile vacuole lies near
the periphery.
Length of body 27µ; of stalk 100µ; of extended tentacle 65µ.
[Illustration: Fig. 67.--_Acineta divisa_.]
Acineta tuberosa Ehr. Fig. 68.
Large forms of _Suctoria_ with tentacles arranged in fascicles. The
stalk is variable in length and the cup is frequently so delicate
that it can barely be made out. A specific characteristic is the
break in continuity of the cup at different points, and through these
places the tentacles emerge in bundles. The tentacles are capitate
and in the Woods Hole form, 15 in number in each of the two bundles.
The endoplasm is granular and yellowish in color. The coloring matter
is frequently arranged in patterns. The nucleus is spheroidal. The
contractile vacuole is in the anterior third of the body about midway
between the bundles of tentacles. Reproduction not observed.
Length of body 330µ.
[Illustration: Fig. 68.--_Acineta tuberosa_.]
Genus TRICHOPHRYA Clap. & Lach. '58.
(See Kent '81; Entz '84; Bütschli '88; Sand 1901.)
Small forms to medium size; no cups or stalks. The body is spherical
to elongate, usually, however, more or less irregularly lobed and
changeable. The tentacles are in fascicles which are usually borne
upon lobed or swollen places. The body is always more or less spread
out. Contractile vacuoles variable. The macronucleus is spherical,
elongate, band-formed or horseshoe-shaped. Reproduction takes place
by endogenous budding, and the swarm spores are flat or lenticular
with a distinct ciliary girdle. They are frequently parasitic. Fresh
and salt water.
Trichophrya salparum Entz '84. Fig. 69.
Bütschli '88; Schewiakoff '93; _Trichophrya ascidiarum_ Lachmann '59;
René Sand 1901.
The body is somewhat cup-form, with a large, flat base. The anterior
border is rounded, each of the ends being somewhat truncate and
carrying a bundle of tentacles all capitate and similar. These may be
continued internally as far as the nucleus (Sand). The cytoplasm is
uncolored, but may contain some brilliant granules. The nucleus is
granular, and spherical, band or horseshoe formed.
[Illustration: Fig. 69.--_Trichophrya salparum_.]
This species was found by Dr. G. Hunter on the branchial bars of the
Ascidian _Molgula manhattensis_, where great numbers of them are
often parasitic.