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Quarterly Journal of Microscopical Science, Vol s3-88, 337-344, Copyright © 1947 by Company of Biologists
1 Zoological Laboratory of Leningrad University
1. The members of the family Ophryoscolecidae exhibit several (5) grades of progressive evolution.
2. An analysis of distribution of different species and genera of Ophryoscolecidae indicates the course of evolution of the family in the several branches of Ruminants where these Infusorians have been sufficiently studied; these branches are: family Camelidae and families Cervidae and Bovidae.
3. A comparison of the distribution of different Ophryoscolecidae with the palaeontological occurrence of their hosts leads to the conclusion that the genera of Ophryoscolecidae arose at different periods, the more complicated ones appearing later than the simpler.
4. The genera Entodinium and Anoplodinium seem to date from the Eocene, while Eudiplodinium and Epidinium appeared only in the Oligocene; the genus Ostracodinium is of a still later descent, and may have arisen in the Miocene. The latest of all to differentiate were the genera Opisthotrichum, Polyplastron, Ophryoscolex, and Caloscolex, belonging to the fourth and fifth, that is, to the highest grades of morphological complexity. Their origin cannot be traced farther back than the end of the Miocene or the beginning of Pliocene.
5. These conclusions are supported by the differences in feeding habits of different Ophryoscolecidae. The more specialized feeding on cellulose-particles has been developed in the higher Ophryoscolecidae, the lower members of the group (Entodinium and Anoplodinium) exhibiting a more diversified diet, combined sometimes with predaceous habits.
6. The need for a study of the yet unknown Infusorian fauna of Lama, and especially of Giraffidae, is emphasized, and some suggestions as to the origin of an aberrant genus of Ophryoscolecidae (Troglodytella from anthropoid apes) are given.
