1964. The accumulation of radio-caesium by marine and brackish water invertebrates. Proc. Symp. Nuclear Detonations mar. Radioactivity, Norweg. Defense Res. Estab., ed. by S. H. Small, Laboratory experiments on the absorption by marine invertebrates of radio-caesium dissolved in sea water are discussed in relation to the potassium concentration of the animal, body size, temperature, and the inactive caesium and potassium concentrations of sea water. The smaller amount of information on the

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... ption by marine invertebrates of radio-caesium from food is then considered, and the laboratory findings compared with the results of field studies. It is concluded that information from laboratory experiments and field surveys should make possible reasonable predictions about the contamination of marine invertebrates if the level of activity in the sea water in particular environments is known or can be estimated. G w B CLARKE, M. R., 1964. Young stages of Lepidoteuthis grimaldi ( Proc. malac. Soc. Lond., Vol. 36, Two specimens of the ' scaled' squid Lepidoteuthis grimaldi are described. Changes associated with growth are discussed and the mantle wall structure is described with details of the 'papillae' of the juveniles and the 'scales' of the adults.