Amazon.com description: Product Description: Presented in 15 extensively illustrated volumes, it provides specific and exhaustive coverage of all the major invertebrate phyla, offering full accounts of their gross, histological, and ultrastructural anatomy. The 15 individual volumes are arranged phylogenetically, beginning with the protozoa, defined herein as the motile protists, and concluding with the invertebrate members of the phylum Chordata. Although gross and external anatomy are discussed in some detail, the emphasis of this work is consistently on functional invertebrate anatomy, particularly at the ultrastructural level. It does not remain limited to fundamental descriptions of anatomical structure but rather goes beyond that level to offer a compelling view of microscopic anatomy that relates structure to function in various organisms.