position as my eighth cirrus. I am positive that cilia do not occur
on the ventral face of this form, and that the characteristic cirri
are the sole locomotor organs.

KEY TO FAMILIES OF PERITRICHIDA.

a. Peristome drawn out into Family _Spirochonidae_
funnel-like process; parasitic

b. Adoral zone and circlet of cilia Family _Lichnophoridae_
at opposite end. Adoral zone (one genus, *_Lichnophora_)
left-wound. Parasitic.

c. Adoral zone a left-wound spiral. Family _Vorticellidae_
Attached or unattached forms.

* Presence at Woods Hole indicated by asterisk.

Genus LICHNOPHORA Claparede '67.

(Gruber '84; Fabre-Domergue '88; Buetschli '88; Wallengren '94;
Stevens 1901.)

Small or medium-sized colorless animals, extremely elastic and
flexible. The anterior part, bearing the adoral zone, is round or
oval in ventral view, and has a flat ventral and a highly arched
dorsal surface. The posterior end of the animal is reduced to a
stalk-like structure which is broadened at the extremity to form
a sucking disk. The surface of this disk and the surface of the
peristome may be brought into the same plane by the characteristic
bending of the stalk portion. A ciliated girdle is placed at the
edge of the sucking disk. A well-developed adoral zone incloses the
peristome; it begins at the mouth on the left side and includes
nearly all of the peristome in its left-wound spiral, the extremity
approaching closely the end near the mouth. The macronucleus is a
long-beaded structure, or it may be in several parts connected by
strands (Gruber). The contractile vacuole is on the left side in the
region of the mouth. Salt water.

Lichnophora macfarlandi Stevens. Fig. 58.

The body is elongate; oral disk variable in form, attachment disk
clearly defined and constant. The stalk is very contractile and
elastic, constantly changing in shape. When detached from the host
the animal moves with a very irregular and indefinite motion. When
attached it moves freely over the surface on its pedal disk. The
latter is bordered by four membranes composed of cilia. A distinct
axial fiber extends from the pedal disc to the peristome and gives
off a number of branches. This fiber is analogous to the myonemes
in _Vorticella_. An indistinct longitudinal furrow can be made out
occasionally. The nucleus is in 5 or 6 separate pieces, of which 1
is found in the pedal disk and 1 or 2 in the neck.