Research whilst compiling this book has uncovered a fauna about twice the size as that previously published in the literature and consequently Systema Porifera revises and stabilizes the systematics of the phylum to accommodate this new knowledge in a contemporary framework. Practical tools (key illustrations, descriptions of character) are provided to facilitate the assignment of approximately 680 extant and 100 fossil genera. Systema Porifera is unique making sponge taxonomy widely available at the practical level of classification (genera, families, order). It is a taxonomic revision of sponges and spongiomorphis (such as sphinctozoans and archaeocyathans) based on re-evaluation of type materials and evidence. It is also a practical guide to sponge identification providing descriptions and illustrations of characters and interpretation of their importance to systematics. Systema Porifera addresses many long standing nomenclatural problems and provides a sound baseline for future debate on sponges and their place in time and space. Systema Porifera describes 3 classes, 7 subclasses, 24 orders, 127 families and 682 valid genera of extant sponges (with over 1600 nominal generic names and an additional 500 invalid names treated). Treatment of the fossil fauna is less comprehensive or critical, although 6 classes, 30 orders, 245 families and 998 fossil genera are mentioned. Keys to all recent and many fossil taxa are provided.

Sponges (phylum Porifera) are known to be very rich sources for bioactive compounds, mainly secondary metabolites. Main efforts are devoted to cell- and mariculture of sponges to assure a sustainable exploitation of bioactive compounds from biological starting material. These activities are flanked by improved technologies to cultivate bacteria and fungi which are associated with the sponges. It is the hope that by elucidating the strategies of interaction between microorganisms and their host (sponge), by modern cell and molecular biological methods, a more comprehensive cultivation of the symbiotic organisms will be possible. The next step in the transfer of knowledge to biotechnological applications is the isolation, characterization and structural determination of the bioactive compounds by sophisticated chemical approaches.

Although sponges are one of the major components of littoral ecosystems, their systematics obviously lags behind that of the majority of other groups of marine invertebrates. Also the evolutionary trends in these most primitive of the Metazoans are poorly understood. The confused state of their taxonomy and the difficulties with their identification prevent their use in ecological studies. The emphasis of interest presently seems to have shifted towards chemistry, but many of the hundreds of interesting chemicals recently described in sponges pro bably have been found in mistakenly or imprecisely identified animals. This situ ation will become worse in the next few years, when a number of experts will retire and will not be replaced by new ones, owing to the difficulties that the science of systematics is facing in most countries - as exemplified during this meeting by an informal discussion on the endangered future of European Museums. Under these circumstances, it is the responsability of present sponge taxono mists to leave a less confused state and tools such as simple fauna or computerized data bases to generations following. These tools do not exist even in one of the best studied areas, the North-Eastern Atlantic (including the Mediterranean Sea).

THE PORIFERA MCQ (MULTIPLE CHOICE QUESTIONS) SERVES AS A VALUABLE RESOURCE FOR INDIVIDUALS AIMING TO DEEPEN THEIR UNDERSTANDING OF VARIOUS COMPETITIVE EXAMS, CLASS TESTS, QUIZ COMPETITIONS, AND SIMILAR ASSESSMENTS. WITH ITS EXTENSIVE COLLECTION OF MCQS, THIS BOOK EMPOWERS YOU TO ASSESS YOUR GRASP OF THE SUBJECT MATTER AND YOUR PROFICIENCY LEVEL. BY ENGAGING WITH THESE MULTIPLE-CHOICE QUESTIONS, YOU CAN IMPROVE YOUR KNOWLEDGE OF THE SUBJECT, IDENTIFY AREAS FOR IMPROVEMENT, AND LAY A SOLID FOUNDATION. DIVE INTO THE PORIFERA MCQ TO EXPAND YOUR PORIFERA KNOWLEDGE AND EXCEL IN QUIZ COMPETITIONS, ACADEMIC STUDIES, OR PROFESSIONAL ENDEAVORS. THE ANSWERS TO THE QUESTIONS ARE PROVIDED AT THE END OF EACH PAGE, MAKING IT EASY FOR PARTICIPANTS TO VERIFY THEIR ANSWERS AND PREPARE EFFECTIVELY.

One of the major questions in the evolution of animals is the transition from unicellular to multicellular organization, which resulted in the emergence of Metazoa through a hypothetical Urmetazoa. The Comparative Embryology of Sponges contains abundant original and literary data on comparative embryology and morphology of the Porifera (Sponges), a group of 'lower Metazoa'. On the basis of this material, original typization of the development of Sponges is given and the problems concerning origin and evolution of Porifera and their ontogenesis are discussed. A morphogenetic interpretation of the body plan development during embryogenesis, metamorphosis and asexual reproduction in Sponges is proposed. Special attention is given to the analysis of characteristic features of the ontogenesis in Porifera. The book pursues three primary goals: 1) generalization of all existing information on individual development of sponges, its classification and a statement according to taxonomical structure of Porifera; 2) revealing of heterogeneity of morphogenesis and peculiarities of ontogeneses in various clades of Porifera, and also their correlations with the organization, both adult sponges, and their larvae; 3) revealing homology of morphogeneses in both Porifera and Eumetazoa, testifying to the general evolutionary roots of multicellular animals, and peculiar features of sponges' morphogeneses and ontogenesis. This book will be of interest to embryologists, zoologists, morphologists and researchers in evolutionary biology.

Need-to-know information on the classification and identificationof aquatic invertebrates This Fourth Edition of the standard reference used by generationsof professionals and students is the source for authoritativeinformation on the natural history, ecology, and taxonomy offree-living American freshwater invertebrates. Completely revisedand updated, this professional field guide features a wealth of newknowledge on invertebrate animal phyla covered in the previousedition as well as fully modified sections on the preparation ofmaterials. Other important features of Pennak's Freshwater Invertebrates ofthe United States, Fourth Edition include: * Current taxonomical arrangements of all freshwater invertebrateanimals, excluding insects * Improved graphical treatments and keys to identification, severalprovided by specialists * Photographs and color plates to aid identification * More than 300 line drawings, many new to this edition * Taxonomic keys carried uniformly to genus level in all but twophyla, with frequent references to species Pennak's Freshwater Invertebrates of the United States, FourthEdition is an indispensable resource for biologists, ecologists,graduate students, and anyone who needs to acquire the thoroughknowledge of aquatic invertebrates that is essential tounderstanding the community structure of freshwater environments.

Modem biology owes much to the study of favorable model systems which fa cilitates the realization of critical experiments and results in the introduction of new concepts. Examples of such systems are numerous and studies of them are regularly recognized by the scientific community. The 1983 Nobel Prize in Med icine and Physiology is a magnificent example in which com plants served as the experimental model. In a manner somewhat more modest, other biological systems have attracted recognition due to their critical phylogenetic position, or indeed because of their uniqueness which distinguishes them from all other organisms. Assuredly, among the whole assemblage ofliving organisms, sponges stand out as worthy of interest by scientists: they are simultaneously models, an important group in evolution, and animals unlike others. As early as the beginning of this century, sponges appeared as exceptional models for the study of phenomena of cell recognition. Innumerable works have been dedicated to understanding the mechanisms which assure the reaggregation of dissociated cells and the reconstitution of a functional individual. Today, re search on these phenomena is at the ultimate, molecular level. Through an as semblage of characteristics the sponges are, based upon all available evidence, the most primitive Metazoans. Their tissues-perhaps one can say their cell groups-are loosely assembled (they possess no tight or gap junctions), cell dif ferentiation appears highly labile, and they do not develop any true organs. But, they are most certainly Metazoans.