A Ciliate, which seems to be new, has recently been discovered in the caecum of cattle in Cambridge. Out of 8 cattle examined 5 were found to be heavily infected, while in 10 sheep and 4 goats there was no infection. I have given the name Buxtonella to the new genus that has had to be established, as it was through the kindness of Prof. Buxton, Director of this Institute, that I obtained the material in which it was first found. The specific name refers to the grooved ridge or furrow which forms the most conspicuous feature of this species.