SIR WILLIAM HEBDMAN did a good day's work forty years ago when he planned out for the Liverpool Marine Biological Committee the series of papers known ever since as the "L.M.B.C. Memoirs". They have put on record, in more or less detail, the structure and natural history of one common animal after another—no small service ; for, as Huxley once said, if the commonest of our British animals became suddenly extinct, we should find we knew next to nothing about many of them. The writing of these memoirs has trained the prentice hand of many a naturalist, among them Ashworth and James John-stone, Cole, Dakin, Eales, Fleure, Hickson, Imms and Punnett. A new part still comes out every now and then, and No. 31 has just appeared; it is by Miss Kathleen White of Reading, on the common mussel.
By Kathleen M. White. (Department of Oceanography, University of Liverpool: L.M.B.C. Memoirs on Typical British Marine Plants and Animals, 31.) Pp. vii + 117 + 10 plates. (Liverpool: University Press of Liverpool; London: Hodder and Stoughton, Ltd., 1937.) 9s. net.