The fine structure of Eadie's ovals isolated from sheep rumen

The structure of two strains of the Gram-negative rumen organism, Eadie's Oval, was examined with the electron microscope. Despite their large size, their fine structure indicated that they were bacteria. They had a cell envelope consisting of two membranes separated by a dense layer which could be solubilized by lysozyme. They possessed characteristic bacterial flagella, and lacked internal organization with ribosomes and DNA-like material dispersed throughout the cytoplasm. The outer membrane was corrugated and each strain had a characteristic pattern of corrugations. One strain had sheathed flagella, the other did not. Both strains were coated with fibrils up to 660 nm long, but which apparently contracted to give an unusual cross-banded layer when treated with lysozyme.