Magnificent Diversity Microscopic Anatomy of Invertebrates, vols 1-3 (1991). Edited by (1) F. W. HARRISON AND J. 0. CORLISS, (2) F. W. HARRISON AND J. A. BUTCHER, (3) F. 1%’. HARRISON AND B. J . BOGITSH. John Wiley & Sons. (1) 508pp. f116.50. (2) 145Opp. f116.80. (3) 362pp. 2116.50. By Janet Moore With the success of molecular biology, the reductionist temptation is strong. Yet study at higher levels also is essential, to provide information which can never be obtained from biochemistry. No amount of knowledge about separate stones can tell us about the architecture of a building; no amount of study of molecules can inform us about the remarkable diversity of invert- ebrates. Further, study at the higher level can inform the lower: appreciation of the diversity which Natural Selection can produce is a necessary dimension for full appreciation of molecular biology.

Microscopic Anatomy of Invertebrates, edited by Harrison and others, is to be a 15 volume treatise which takes the first step up the ladder of levels of integration. ‘Microscopic anatomy’ is defined primarily as cellular studies at the ultrastructural level. At once, it is obvious that further steps up the ladder must be taken and that studies at higher levels of integration will be required to achieve the stated aim of providing the definitive reference on invertebrates. The focus is to be on functional morphology, the dedication is to Libbie Hyman, but the reductionist devil has not been exorcised if the electron microscope is the only tool employed. This is not to complain that the work isn’t something quite different, but to emphasize that the stated aim cannot be achieved in these terms.

The first volume concerns Protozoa - defined as the primarily motile protista. After a general introduction by the co-editor of this volume, J. 0. Corliss, chapters describe the Mastigophora, the Sarcodina, the diverse groups of the ‘Sporozoa’ and the Ciliophora. For Protozoa, of course, microanatomy does mean electron microscopy study, and these accounts, by well known experts with fine illustrations, are very full and up to date.

In the second volume the accounts of the least coordinated Metazoa, the Placozoa (by K. G. Grell and A. Ruthmann) and the Porifera (by F. W. Harrison and L. de Vosj are essentially of the same kind as those in Volume 1 and most usefully bring the reader up to date. Cnidaria however already present problems, since microanatomy at the cellular level is not enough to depict the functional anatomy of these animals. The section on Hydrozoa (M. B. Thomas and N. C. Edwards) does include some good histological diagrams as well as the nice electron micrographs, but is tantalisingly restricted: for example, coordination of morphogenesis and of movement is judged to be outside the terms of reference. Nerve cells are described, but not the morphogens now known to be

bound to their membranes, nor is the functioning of the nerve net discussed. Scyphozoa and Cubozoa (G. E. Lesh-Laurie and P. E. Suchy) are more uniform and less extensively studied groups; here a most welcome extension of microanatomy is applied, and the account of nerve and muscle cells includes a description of the swimming behaviour of these medusae. The section on the Anthozoa (D. G . Fautin and R. N . Mariscal) is outstanding, being particularly interestingly written, well integrated and profusely illustrated, giving as full an account of functional morphology as the constraints allow. The final chapter on Ctenophores (M.-L. Hernandez-Nicaise) gives a full structural description of this essentially uniform phylum.

The third volume (co-editor B. J. Bogitsli) concerns Platyhelminthes and Nemertinea. The classification of Platyhelminthes is highly controversial - here the three traditional taxa are retained for convenience. There is a very full and beautifully illustrated account of ultra- qtructure in Turbellaria, with nearly 800 references. In the (subdivided) Trematoda the large number of forms inevitably makes for less detailed description. Larvae are discussed first in each group. Challenging state- mcnts include ‘the protoncphridial system.. .persists into the adult and therefore has taxonomic impli- cations‘. Information on Cestoidea is primarily derived from tape worms parasitic in birds and mammals: scoliccs provide stunning S.E.M. pictures. Systematic division of this phylum was unavoidable, but it did lead to repetition in description of structures (such as flame cells) which are common to all subdivisions. Nemer- tines are unusual in that most species can only be identified by histological study of serial sections. To neglect microaiiatoiny at the light microscope level is therefore, sadly, to miss an opportunity. The compen- sating gain comes in the review of neinertine ultrastruc- ture. As is possible for a phylum so little studied, J. Mc.C. Turbeville’s account is complete (up to 1988) and for that we must indeed be grateful. This account of ultrastructure i s concerned not with functional mor- phology but with possible clues to phylogenetic relationships. The author has demonstrated that certain structures in nemertines, the rhynchocoel and in particular the blood vascular system, develop very similarly to the annelid coelom: he deduces that nemertines had a coelomate origin. This theory is not widely held: it is disputed by workers on the nephridial system and by those impressed by the general prevalence of convergent evolution in nemertines. Turbeville is careful to record that his theory is controversial, but homology is too readily assumed and the balance of the chapter is upset.

Who will benefit from these books? A treatise on this scale is clearly more for specialists than for ytudents. It is fascinating to be brought up to date on microscopic anatomy, but this by itself cannot describe ‘the magnificent diversity of invertebrates’; here the editors’ aim was doomed to fail. That caveat registered, the

emphasis must be to welcome this public spirited project. Many workers will find it very useful to have assembled accounts of the ultrastructure of different invertebrates.

Janet Moore is at the Department of Zoology, University of Cambridge, Cambridge CB2 3EJ.

Texts and Pretexts Biology, Concepts and Applications (1991). Edited by CECIE STARR. Wadsworth Publishing Co, Bclmont, California. 654pp. €15.49 paperback. Zoology (1991). Edited by ROBERT DORIT, WARREN WALKER AND ROBERT BARNES. Saunders College Publishing, Philadelphia. 1022pp. 217.95 paperback, E40.50 hardback. By Martin Wells In the last couple of decades, selective pressures have determined a great deal of convergent evolution in textbooks. Now, to survive at all, a textbook must be immaculately produced and lavishly illustrated with photographs of whole organisms. seen from the outside, and diagrams of their internal structures, greatly simplified and in strange colours (students don’t much like dissecting animals these days, so that they will probably never realise that the creatures really are not like that inside). The text must be broken up, with multicoloured boxes, for an easy read. To keep the price down to a level where students can afford to buy the books, publishers have to sell an awful lot of copies.

So the aim is to issue a book that is all things to all people, or anyway to all biologists, something that could form a background to any number of potential courses. To encourage teachers to adopt the texts, each includes an introduction explaining this and offering supplements ’that range from lecture outlines through overlays and laboratory manuals to discs with self-test computer programs for students. The book is only part of the package. Because of the range of material

concerned - everybody wants to include the molecular as well as the whole organism stuff - each section has been reviewed by one or more specialists, so that the author(s) are editors, collating material from a committee. Quite a committee, at that. Starr’s Biology lists more than ninety reviewers, Dorit et aZ.’s Zoology a mere (by comparison) forty or so. Most cost them a fortune in giveaway copies.

Within these convergent constraints the books differ considerably. Zoology is the more specialised of the two. It deals with animals and prokaryotes only (except. inevitably, for Mendel’s peas). It achieves cohesion by concentrating on the evolution of animals. Good basis of genetics (to a non-geneticist, this part seemed to be particularly well explained), emphasis on history; animal diversity is only accountable if we accept that animals have an evolutionary past as well as a functional present. It covers a lot of familiar territory in a familiar way. perhaps because two out of the three authors have already written well-known textbooks on vertebrate and invertebrate structure and function, running into multiple editions.

Biology is more ambitious. It covers plants as well as animals and the inevitable molecular biology. a wider range in two-thirds the number of pages. It cuts corners, inevitably. Items like the bird lung are simplified to the point of untruth, there is no such thing as a haemocoele (which may puzzle students dipping into other accounts of body cavities), and it is surely naughty to give the impression that all past mass extinctions can be blamed on meteorites. But these are quibbles about a successful attempt to pour gallons of biology into a quart pot while at the same time emphasising the human relevance of it all. Bzology prominently links the material it presents to topical issues like AIDS and anorexia, genetic engi- neering and the greenhouse effect. This is a book that might convert a student to biology. Zoology is a text for the already converted.

Martin Wells is at the Departmcnt of Zoology, Cambridge CB2 3EJ.