Since writing the first report on the arthropods of the Rhynie Chert beds (see Ann. Mag. Nat. Hist. (9), xii, pp. 455–74, 5 pls., and 13 text-figs.) some additional specimens of Palaeocharinus have been collected. A few examples are fairly complete and well preserved, showing a considerable amount of structural detail, such as the chaetotaxy, claws of the legs, ornamentation of the chitin, eyes, etc. An account of the lateral eyes is given below. We also include notes on a supposed insect and another fossil arthropod which we refer with doubt to the aquatic Merostoma. All the illustrations in this little paper have been drawn by Miss Violet Borrow, A.R.C.A., with the aid of a camera lucida under our personal supervision.