Recent Xenophoridae

Carrier "Shells have long fascinated scientists and laymen alike with their habit of fixing foreign objects - shells, pebbles or coral etc. to the surface of their own shells. This book gives a welcome popular coverage to the living members of the family."

After acknowledgements and introduction, the book continues with a general discussion of the Xenophoridae. This includes an overview of the various hypotheses which have been used to explain why Xenophora add foreign bodies to their shells -visual camouflage (the usually accepted reason), olfactory camouflage, tactile camouflage, to prevent the shell sinking in soft sediments, to increase the strength and/or size of the shell, to improve the shell's stability in strong water currents or to provide a safe feeding area for the living Mollusc. All these are discussed in one of the clearest accounts which I have read. I would personally have liked to have had some more information included on the living Xenophoras, habitat preference and feeding preference are only mentioned in passing, and there is no description/illustration of a living animal. While I realise that little is known of this aspect of the Xenophoridae to have covered this in greater detail would have been useful and might have encouraged field collectors to add to our current scanty information.

There follows a key to identify recent species first to generic then to specific level. Having tried this with a number of specimens I have found it to work well, provided that one has at least basic locality data for the specimens - seven of the nineteen steps in the key are of geographic separation - since as the authors say "Species in the genus Xenophora are highly variable in almost all of their shell characteristics. Consequently, many species cannot reliably be identified by a single morphological feature; rather, sets of such features have to be used. However, some species have well-defined geographic ranges so that information on the locality in most cases will allow successful species identification." For non English speakers this identification key is helpfully repeated in German, French and Italian.

The bulk of the book consists of a systematic account of the 26 living species/ subspecies considered valid. Information for each species includes; data on type speci- mens, type localities and range of the species. Together with descriptions covering the height of the shell, diameter of the base, angle of the spire, colour and sculpture of both the dorsum and base, the shape of the base, size of the umbilicus, and extent of attached objects. Additional comparisons with similar species help to emphasise differentiating characteristics.For each species a detailed synonomy is given with full page references for valid taxa and abbreviated references - author and date only - for synonyms. Interspersed with this text are some 20 illustrations reproduced from 'classic' shell books of the past, some of these illustrations being from the original descriptions of the species - together with some 44 black and white photographs, many showing enlarged details of the basal sculpture. Overall the text is both clear and concise, although the inclusion of a short glossary might have been helpful for the ordinary collector, where terms like opisthocline and prosocline are used. The text is relatively free of errors - on p. 67 Hamley should read Hanley, and the date of publication for Buonanni's "Ricreatione dell' occhio e della mente . ." should be 1681 not 1841, while on p. 56 the subgenus Austrophora is misprinted as Austroharpa, I would have expected this to have been picked up on proof reading given that the two authors helped describe this subgenus.

Twenty-eight full colour plates clearly illustrate each species from dorsal and ventral perspective and in profile, while by illustrating several specimens for each species the authors help to show the variability within the species. The quality of the colour plates is excellent although in one or two instances the lighting used has affected the colour tone, for example in two views of the same specimen of Xenophora japonica in one picture the shell appears white and in the other yellow.

Other sections of the book include a listing of Xenophoridae by geographical distrib- utions, a list of recent taxa and an index of valid taxa. Finally there is a six page Bibliography, and it is unfortunate that this should let down the otherwise high stan- dard of the book. For example in the discussion of the collecting habits of Xenophoridae references are made to eleven works, of these seven cannot be found in the Bibliography. Most surprising is the inexcusable omission of W. Ponder's "Xenophoridae of the World" (Australian Museum Memoir 17:1983) which was the first comprehensive revision of the family for some 100 years; the authors frequently refer to Dr Ponder's work throughout their text and moreover Dr Ponder provided the foreword to their work.

This book can be recommended to anyone interested in this fascinating group, and will make their identification much easier in the future.