The Nature Conservancy is expected to advisethe Red Deer Commission on the scientific aspects of red deer (Cervus elaphus L.) management. Although work on the management of red deer has been in progress since 1957 on the Isle of Rhum National Nature Reserve (Lowe 196 1; Eggeling 1964), it was essential to develop methods for assessing the relevance of the results to deer populations elsewhere in Scotland (Mitchell 1965). Accurate determination of age is an important prerequisite for comparing the growth, breeding performance and survival of different deer populations. Changes in body characteristics with age can 6ften be used for the exact determination of age of short-lived animals. But for those with a long life span, the time required to collect the relevant age characteristics may be a serious restriction. Similarly, the characteristics of one population may differ from those of another, and it is reasonable to expect less accuracy with increasing age. Although annular tissues and structures have been long known in woody plants and fish, it is only in recent years that progress has been made in the quest for similar tissues among mammals. Dental tissues have attracted most attention, and whereas. the earlier studies concerned growth layers in dentine, e.g. in red deer (Eidmann 1933), Alaskan fur seals (Callorhinus ursinus (L.)) (Scheffer 1950), elephant seals (Mirounga leonina L.) (Laws 1952, 1953), harp seals (Phoca groenlandica Erxleben) (Fisher & Mackenzie 1954), bottle-nose dolphins (Tursiops truncutas (Montague)) (Sergeant 1959) and Alasklan black bears (Ursinus americanus (Pallas)) (Rausch 1961 in Mosby 1963), later work has indicated the wider potentiality of dental cement. Dentine grows internally, progressively filling the pulp cavity, but cement continues to grow n -the root surface, apparently at a constant rate, throughout life. Hence annual cement increments are relatively constant, but dentine increments tend to get smaller, and, more difficult to count, with age. The linear relationship between cement thickness and age found in human teeth (Gustafson 1950 in Miles 1961) has been suggested as a possible method of forensic age assessment. Encouraging results using annular cement layers for age determination have been published for moose (Alces alces (L.)) (Sergeant & Pimlott 1959), harbour seals (Phoca vitulina L.) (Mansfield& Fisher 1960), grey seals. (Halichoerus grypus Fabricius) (Hewer 1960, 1964), Barren Ground caribou (Rangifer tarandus groenlandicus (L.)) (McEwan 1963), beavers (Castor canadensis Kuhl) (Van Nostrand & Stephenson 1964), griizly bears (Ursus arctos L.) (Mundy & Fuller 1964) and white-tailed deer -(Odocoileus virginianus Zimmermann) (Ransom 1966; Gilbert 1966). In an earlier note (Mitchell 1963) I showed how growth layers in the dental cement of red deer could be exposed by sectioning the thick cement pad under the crown on molar