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.

On the egg capsules of _Crepidula plana_; also reported upon annelids
at Woods Hole.

Length 60µ from disk to extremity of the peristomial disk.


[Illustration: Fig. 58.--_Lichnophora macfarlandi_.]


This form does not agree in all respects with Stevens's species, but
the agreement is so close in other respects that I believe it can be
safely identified as _L. macfarlandi_. The mode of life is different,
and the macronucleus is different, there being from 25 to 30
fragments in Stevens's form and only 5 or 6 in the present one. There
is, however, the same evidence of chain formation in both of them.
The length of the oral cilia in Stevens's form is 18µ in fixed and