A morphological and cytological study of Macrostomum appendiculatum (O. Fabricius)

The purpose of this present work, when first begun, was to describe one of the Turbellaria, belonging to the genus, Macrostomum, which apparently differed from the species already reported in this country or elsewhere. A careful examination, however, revealed no major differences existing between those species described in the literature as M. sensitivum and M. appendiculatum and those existing around the University of Virginia. Certain variations in the morphology of the sexual organs were found; but these are not of sufficient value to warrant the erection of a new species or even of a variety.

During the course of this preliminary study, the author became interested in the cytology of the developing egg of M. appendiculatum. This, together with an account of the development of the egg, as well as an account of certain variations in the structure of the form found around the University of Virginia constitute the results presented in this paper.