Since publishing, with Mr. Lapage, the first account of the life-cycle of Helkesimastix facicola , I have continued to work alone on the biology and life-history of the flagellates occurring in simple dung-cultures. In the course of this investigation, I have made certain observations which I wish here to record, together with one or two suggestions which I have to offer. The work promises to occupy considerable time before it is completed, and in the case of some of the forms studied I am not yet able to describe the life-cycle in its entirety. Little or no attention has been paid hitherto to the protozoa active in dung, and the study of this fauna is probably not without interest and importance in connection with the subject of the soil-protozoa. To distinguish those protozoa which are carried through the alimentary canal in a passive, encysted condition and become active and go through their life-history in the moist dung, Prof. Minchin has suggested, in the course of his lectures, the useful term coprozoic . The coprozoic fauna of goats and sheep is entirely different from their parasitic fauna, which has for its principal habitat the rumen. Neither the various specialised ciliates (of the fam. Ophryoscolecidæ ) nor the flagellates ( Sphæromonas , Trichomastix and Callimastix ), some of which are invariably present in the rumen, ever occur in an active condition in dung-cultures; and, on the other hand, I have never found any of the coprozoic flagellates active in the rumen-contents, when freshly examined. These facts, readily determined because the sets of forms in the two cases are entirely different, afford important confirmation of the view, now generally accepted, that the Entamæbæ —the truly parasitic forms—are quite distinct from the Amoebæ which develop in fæcal cultures, i. e .,coprozoic species.