OBSERVATIONS ON EUGLENA LEUCOPS, SP. NOV., A PARASITE OF STENOSTOMUM, WITH SPECIAL REFERENCE TO NUCLEAR DIVISION

¹ MILLER SCHOOL OF BIOLOGY, UNIVERSITY OF VIRGINIA

A new species of chlorophyll-free Euglena, E. leucops, is described, and though it lacks color, the presence of a stigma and the bifurcation of the flagellum place it in the family Euglenidae.

A flagellum is not present while the parasite is in the host but is elaborated quickly outside the host if favorable conditions of osmotic pressure prevail. This organelle is capable of repeated growth.

The stigma has been followed through binary fission and found to divide, but not always equally.

Nuclear division is described. The "chromosomes," which remain distinct, even in the resting nucleus, divide transversely during the metaphase.

Osmotic pressure apparently may initiate and accelerate cell division.

Attempts to cultivate the parasite in vitro failed.

The host may be easily cultivated and the infection readily continued.

No evidence of encystation has been observed.

Observations upon the flagellates for more than a year have given no evidence of a method of division other than binary fission involving mitosis.