MORPHOLOGY AND LIFE HISTORY OF POLYTOMELLA CITRI SP. NOV

¹ UNIVERSITY OF CALIFORNIA AND PRINCETON UNIVERSITY

The flagellate herein described belongs to the genus Polytomella (Aragao, 1910). The specific name "citri" is proposed. The size ranges from 10 by 7 micra to 14 by 10 micra. Outside of the absence of chlorophyll the structure is typical for the family Polyblepharididæ. Although it is a colorless, saprophytic organism the cell-body contains numerous starch bodies.

The life history consists of active stage, in which reproduction is by binary fission, and encystment. No reproduction takes place during encystment. There is no indication of any sexual process at any point of the life cycle.

Conjugation is not well established in any species of the family.

The chromosomes arise as a result of the fusion of chromatin particles which have come from the karyosome.

The cysts are filled with metachromatic granules. They usually disappear before excystment.

A new centriole and basal granules are given off from the karyosome previous to excystment. Flagella do not grow out until the cell comes in contact with the outside. Amboid movement is the means of locomotion for several minutes following excystment.