Book review

Within a time span of ten years Van der Spoel has succeeded in completing and seeing through the press a second volume of his series on planktonic molluscs. The first volume appeared in 1967 and is entitled “Euthecosomata, a group with remarkable developmental stages” (for review see Basteria 32: 47-48, 1968). This volume was favourably received and has since been widely used. Now the author has tackled the difficult Pseudothecosomata, Gymnosomata and Heteropoda with the same thoroughness and zeal as the Euthecosomata. The volume consists of seven parts, viz., Introduction (14 pp.), Taxonomy (146 pp.), Distribution (18 pp.), Type material (28 pp.), followed by two appendices (distribution maps, keys with figures, together 21 pp.), an annotated list of references (83 pp.), and the 246 figures (166 figs. and 81 maps, together 166 pp.). In general set-up both volumes are entirely comparable; both will be reference books of great value for many years to come. Van der Spoel’s beautifully illustrated and detailed treatment of the taxa reflects a thorough training in taxonomy. The complete literature has been evaluated in addition to studies of a profuse material. Van der Spoel is a gifted artist as shown by his exquisite drawings. Particular features of the second volume are, (1) the Additions to the Euthecosomata (pp. 48-61, bringing the 1967 volume up to date), (2) the lists of type material (pp. 187-214, giving details of types, their whereabouts, etc., also for the Euthecosomata), (3) the most valuable distribution and diversity diagrams (pp. 216-220, also for the Euthecosomata), and (4) the new keys for the identification of all Pteropoda and Heteropoda (pp. 221-235; these will enable even comparative laymen such as oceanographers to get fairly reliable identifications quickly).