8. Membranelles normal; 5-10 anal Genus *_Amphisia_
cirri; no caudal cirri
Membranelles normal; 5 to 10 anal Genus _Stylonychia_
cirri; 3 caudal cirri
Membranelles very large and Genus _Actinotricha_
powerful; adoral zone not
continued to mouth; 5 anal cirri
* Presence at Woods Hole indicated by asterisk.
Genus EPICLINTES Stein '62.
(Stein '62, '64, '67; Mereschowsky '79; Gruber '87; Bütschli '88.)
Very active, contractile, colorless forms of rather small size. In
the fully expanded condition the body is oval and long, with its
greatest width in the center or at the front half of the body. The
posterior end is always drawn out into a relatively long tail, which
is extremely elastic. The peristome is short and stretches around the
front end of the animal. In the frontal region are from one to three
rows of cirri. The ventral surface is covered with longitudinal rows
of cilia, the number of rows being in dispute (6 to 7 according to
Stein; 9 according to Mereschowsky and Rees) Some of these cilia
project from the lateral edges and from the posterior end, where
they are slightly elongated. The anus is dorsal and placed at the
beginning of the posterior process. Macronucleus probably double.
Movement is rapid and restless, the tail process contracting to jerk
the body backward. Salt water.
Epiclintes radiosa Quenn. Fig. 50.
Synonym: _Metra radiosa_ Quenn.
The body is elongate, slightly narrowed anteriorly, and drawn out
posteriorly into a long, retractile, tail-like portion. Five large
cirri extend outward from the anterior extremity. The caudal portion
may be extended to a distance equal to twice the length of the body
or contracted to half the length. The peculiar nervousness of this
form made it extremely difficult to study, and the oral region was
imperfectly made out. The anterior cirri appear to line the upper
left border of the peristome, which is marked by a row of large
cilia. The peristome begins upon the right side of the anterior end
and passes backward and to the left, narrowing at this point. The
mouth is very small and difficult to see. It is apt to stay in
one locality under zoogloea, switching back and forth with great
vivacity, or hanging on by the posterior cilia while the anterior
end stretches out in the surrounding medium. Nucleus and contractile
vacuole were not observed. Length 45µ.
[Illustration: Fig. 50.--_Epiclintes radiosa_.]
Genus AMPHISIA Sterki '78.
(Sterki '78; Kent '81; Bütschli '88.)
The body is plastic and soft, colorless or slightly tinged with
yellow or red. In form it is oval or elongate, the posterior end
is rounded and slightly reduced in diameter, but does not form a
distinct tail. The anterior end is also rounded and similarly reduced
in width. There are two rows of marginal cirri (_Randcirren_), which
may be placed some distance from the edge, and two or three rows of
ventral cirri between them. There are from 3 to 5 frontal cirri of
larger size than those of the ventral rows, and from 5 to 10 anal
cirri. (The genus _Holosticha_ is similar in all respects save
the presence of frontal cirri.) The macronucleus is double; the
contractile vacuole is central and on the left side. The peristome
is long and rather narrow and carries an undulating membrane on its
right margin. Fresh and salt water.
Amphisia kessleri Wrzes. '77. Fig. 51.
Synonyms: _Trichoda gibba_ Müller; _Oxytricha gibba_ Stein '59; _O.
velox?_ Quen. '69; _O. kessleri_ Wrzes. '77.
Body elongate, slightly sigmoid and swollen in the center, about
3-1/2 times as long as broad; the rounded anterior end is turned to
the left, the similarly rounded posterior end to the right; both ends
taper slightly. The peristome is long and narrow, with a distinct
adoral zone which appears broken in its course. To the right of this
adoral zone is a single line of preoral cilia. On the right border of
the peristome is an undulating membrane. The three frontal cirri form
a triangle and the five smaller anal cirri form a continuous line
with the broken row of ventral cirri. There are two and one-half rows
of ventral cirri and the marginal cirri are drawn in until they are
ventral in position.
Length 135µ; greatest width 40µ.
[Illustration: Fig. 51.--_Amphisia kessleri_.]
This variety differs from _O. kessleri_ as described by Wrzesniowski
in having three frontal cirri instead of four. Another difference
is in the structure of the nuclei and in their position. These
differences are too minute to warrant a specific name. _O. velox_ of
Quennerstedt is probably the same as _0. kessleri_, but differs in
having three complete rows of ventral cirri. _O. velox_ has three
frontal cirri in a line, thus differing from the Woods Hole form.