THIS book is a worthy companion to the same author‘s book, "The Trematoda"(Cambridge University Press, 1946). The author modestly says that he does not claim to have given an exhaustive account of the trematodes of British fishes, and it has naturally been difficult to decide whether some marine fishes caught off the coasts of the British Isles should be classified as British species or not. New records of species parasitic in particular hosts will certainly be made from time to time as fishes are caught and examined, so that no systematic account written now can hope to be complete. But Dawes has collected, in the 286 pages of classification and systematic descriptions of species in this monograph, the information available at present. To this he adds 26 pages of references to the literature and a list of the British fishes in which the trematodes occur. Both these latter- features greatly add to the value of the book. Five chapters give concise accounts of the Platyhelminthes, the three orders of Trematoda and the morphology of the Monogenea, the Aspidogastrea and the Digenea. Many zoologists will find these chapters valuable, quite apart from the systematic details which follow them. A concise account of the Monogenea will be especially useful. The Trematoda of British Fishes By Dr. Ben Dawes. (Ray Society, Vol. 131 for the Years 1944 and 1945.) Pp. viii + 364. (London: Bernard Quaritch, Ltd., 1947.)