IN the Sound of Harris, the channel between Lewis and North Uist, there is a cluster of small islands and rocky shoals. Pabbay, with its small neighbours the Shillays, a haunt of seals, lies some 4 miles out in the Atlantic. Beyond is only St Kilda, 40 miles to the west. Seen from the motor boat that carries one for an hour and a half from Rodel, in South Harris, between the islands of Killegray and Ensay, and past some seal-inhabited skerries, Pabbay appears as a broad-based triangular hill, with sand dunes covering the inner shore (P1. II, phots. 1, 2). From the top of this hill, which is called Beinn a' Charnain and rises to 644 ft., one can see a panorama of islands. In the Sound and just outside it are Lingay, Boreray, Spuir, Berneray, Coppay, Killegray, Ensay, the Saghays, and many others. To the south are the Haskeir Islands, breeding place of the grey seal. Far to the west is the St Kilda group, rising steeply from the Atlantic. Taransay lies to the north, not far from the Harris mainland. It was with the idea of learning something about the mammals that I spent the week of 8-14 August 1935, camping on Pabbay, with the kind permission of the owner, Mr R. Campbell of Rodel, who also provided transport. I am grateful to all who gave me information; but especially to Messrs Donald