Biology of Opisthobranch Molluscs: Volume 2.

Submitted by Steve Wilkinson on Sun, 09/05/2010 21:46

T. E. Thompson and G. H. Brown. Published by the Ray Society, London in 1984. pp 229, 41 plates, 40 text figures, 98 distribution maps, 107 line drawings of British naked Opisthobranchs. ISBN 90 3874 180.

Review source

Originally reviewed by IaTom Gascoigne in 1985.

Published in Journal of Conchology (1985), Vol.32

The first volume of Biology of Opisthobranch Molluscs (Thompson 1976) begins with chapters on Classification and Affinities, Locomotion, Food and Feeding, Defence, Reproductive Organs, Development, Larval Biology and Life Cycles. The second half of Volume 1 deals with British Opisthobranch species of the orders Bullomorpha, Aplysiomorpha, Pleurobranchomorpha, Acochlidiacea, and Sacoglossa (=Ascoglossa).

Volume 2 (Thompson and Brown 1984) continues straight on from the first with an account of 108 British species of Nudibranchia, an order which includes some of the loveliest sea creatures. A more precise and informative table for both volumes would be British Opisthobranch Species, for the main theme of both volumes is British species, their classification, descriptions, and biology.

T. E. Thompson has the bold, roving spirit of an Elizabethan sea-captain. For more than twenty years he has made annual voyages to the distant shores of America, Australia, Africa, the far East, and the Mediterranean. Each year he has returned with new species, changes in classification, and interesting observations on the biology of Opisthobranchs - proofs of vast expertise and sound judgement. He is justly regarded as a leading authority on world Opisthobranchs. The junior partner Gregory Brown, is a good artist and a well-trained zoologist@a rare combination! He is a keen collector of nudibranchs and has carefully observed the living species which he has faithfully depicted in Volume 2. Recently he revised the Data complex that Lemche left. Both authors have successfully collaborated in a field guide, British Opisthobranch Molluscs (No. 8 in the Linnean Series). By their talents and experience they are well-equipped to write a work of the high standard expected by the Ray Society.

The Ray Society was founded in 1844 by a group of British zoologists to promote and fund the publication of important works, mainly about the British fauna. Their first publication was A Monograph of the British Nudibranchiate Mollusca by Alder and Hancock (1844-1855). Their descriptions were far in advance of the time and where it was illustrated by beautiful chromolithographic plates. It would have been interesting if Thompson and Brown had written a chapter comparing Volume 2 with Alder and Hancock's monograph. By this chapter we could have been informed what new species had been discovered, what changes in classification and advances in nudibranchology have been made since the days of Alder and Hancock. The production of their monograph almost exhausted the funds of the Ray Society. With the wisdom of hindsight, the Society have priced Volume 2 at £39 a copy.

In general plan the volume resembles a German Handbuch. It is attractively produced, splendidly illustrated, and the style is simple and direct. Malacologists will find it an indispensable modern reference work. A collector could identify a British nudibranch and learn much about its biology by the use of this book. Although there is a very comprehensive reference list some research workers might wish for more details and discussion in the text.

In the present century Opisthobranch specialists have continued to find new Opisthobranch species. They have been so successful that the number of Opisthobranch species has almost doubled. Some specialists have described new species almost entirely by external features. Others have restricted observations on internal anatomy to descriptions of the radula. A glance through Volume 2 shows that 19 of the 40 text-figures and 4 of the plates illustrate teeth details. There are no text figures of complete alimentary or reproductive systems. So meagre is the information given in the literature that if Thompson and Brown had decided to write Volume 2 in the academic style exemplified by British Prosobranch Molluscs (Fretter and Graham 1962) they would have found the task almost impossible. Nevertheless they might have included 2 or 3 text-figures illustrative of reproductive details pour encourager les autres.

The colour plates were produced from water-colours by Gregory Brown. Large species look strikingly effective against a black ground, which also enhances to delicate colours of smaller species. Brown's 98 line drawings of naked Opisthobranchs are excellent. They show a patient attention to detail and a natural representation of the living species that is pleasing to zoologists. They will be a valuable aid to identification. Dichotomous keys are given, but the beginner would be well advised to accompany the experts of the Conchological, Malacological, Porcupine Societies on their field meetings and learn to identify a number of species before relying on keys.

Volume 2 will remain the standard reference work in British Nudibranchs for many years. It is hoped that the authors, after about two decades, will write a Supplement to bring their work up-to-date.