The Aleut, Dr. Waldemar Jochelson, as the leader of the ethnographical section of the great Ria-boushinsky Kamchatka-Aleutian Expedition, spent the years 1909–10 in the investigation of the arch¦ology and ethnology of the Aleutian Islands. The results, submitted to the Russian Academy of Sciences in 1916, remained unpublished owing to the War, until 1925, when an archæological volume was published by the Carnegie Institution of Washington. Dr. Jochelson has now issued, through the Institution, a monograph (Publication No. 433) dealing with the history, ethnology and anthropology of the Aleut. The expedition secured seventy skulls, of which fifty were in a sufficiently good state of preservation for measurement. They showed an average cranial index of 821 with a standard deviation of 27 and individual range of 78-88. As these skulls were from pre-Russian graves, the conclusion is that the Aleut were not a pure race. Measurements by Mme. Jochelson of 138 living individuals gave a cephalic index of 84 with a standard deviation of 33 and individual range of 76-94; this, allowing two units, agreeing substantially with the skull measurement. Thus it would appear that contact with the Russians did not affect head measurement. Comparison with neighbouring Indians and Pal¦oasiatics shows the Aleut to be higher than all in comparative head breadth: for example, cephalic index of Alaskan and Siberian Eskimo, 79 and 80 respectively; Koryak, Kamchadals and Yukagir, 78, 79, 80 respectively; and Indians Tlingit, Tshimshian, etc. not more than 82. Two explanations are possible: either a mixture with Athapascans, some of whom are so high as 84, or the acquisition of a superbrachycephalic index after a period of isolation. The latter would be a modification comparable to that attributed by Boas to the physical characters of immigrants to America or those found recently in Russia as the result of a starvation diet.