This small but important book is one of the series of Guides presently in preparation. The first rotifer volume (Rotifera, vol. 1 : Biology, Ecology and Systematics, 1993) summarized the general biology of rotifers whereas the second volume (The Lecanidae) and all the following volumes concern the taxonomy and identification keys of individual genera.
The third volume of the series deals with the most difficult family among monogonont rotifers. The authors of the key describe the family Notommatidae as "a taxonomically unsatisfactory assemblage of diverse taxa, in need of revision by modem methodology". It has to be emphasized that the authors themselves do a lot in this respect as there are some very important changes in the taxonomy of the family described in their guide.
Phenotypic similarity among and within genera makes identification of species in Notommatidae extremely difficult. The authors have done their best to help readers in this respect. The introduced methods of numerical taxonomy, using the NTSYS-PC package of computer programs written by F. J. ROHL. The method however could not be used for both species-poor and species-rich taxa. Thus, in some cases both a multiple entry key and a dichotomous key are supplied. That makes the guide so mew hat chaotic .
Apart from keys to families, subfamilies and genera the book contains a descriptive part, in which each species is carefully described using a common scheme consisting of: Type locality, Holotype, Description, Ecology, Literature and in a few cases -Comments. It puts more order into the book. It is a great pity that figures reproduced from literature have not been standardized and are of a very different quality.
This new and greatly improved guide to the Notommatidae and Scaridiidae will be of enormous value to professional biologists. There are only very few specialists with knowledge adequate to deal so expertly with such a difficult group of animales. T. NOGRADY, R. POURRIOT and H. SEGERS are among the best of them.
J. EJSMONT-KARABIN