5. THE PHYLUM PROTOZOA
183
Life cycle. The complete life cycle of A. isseli is not known but
conjugation and nuclear reorganization in this species have been
demonstrated by Kidder (1933~).
Nothing is known about the ecology of A . isseli except
that it too possesses thigmotactic cilia. Kidder (1933~) has reported
that while swimming this ciliate tends to do so in one direction.
Ecology.
,MN
F
FIQS. 86 and 87. Ancistrum isseli. (86) Ventralview; (87) dorsal view. C V , Contractile
vacuole ; F V , food vacuole; M N , macronucleus. (Redrawn after Kidder, 1933c.)
Physiology. Kidder has demonstrated that the food vacuoles of
A . isseli are filled with the yellow pigment of its host, Modiolus modiolus,
but it is not known whether the ciliate actively ingests its hoat’s
pigment-bearing tissues.
5. Ancistrunz japonica Uyemura, 1937. (Fig. 89)
(Subclass Holotrichia; order Thigmotrichida; family Hemispeiridae)
Ancistrum japonica was described by Uyemura (1937) from within
the mantle cavities of several species of marine pelecypods including