The Evolution of the Metazoa

Zoology, Volume 16: The Evolution of the Metozoa presents the significant results of the Cnidaria research, their interpretations and implications in the field of zoology.
This book is composed of four chapters, and begins with the establishment of the systematic position of the Spongiae, the position of Ctenophora in the animal classification, and Cnidaria as the only Coelenterata. The subsequent chapter deals with a critical survey of the interpretations of the origin and nature of Cnidaria, with emphasis on the morphologic proofs of its phylogeny. These topics are followed by an outline of the most probable reconstruction of the phylogeny of Cnidaria and the descriptions of the evolution of this metozoa. The final chapter considers the established classification of the animal world and the genealogical tree. This book will be of value to zoologists and researchers who are interested in evolution and classification of Cnidaria.

Preface

Introduction

Chapter 1. Cnidaria as the only Coelenterata

The Systematic Position of the Spongiae

The Systematic Position of the Ctenophora

Cnidaria as the only Coelenterata

Something about the Methods that can be Used in Connection with the Construction of the Natural Animal System

The Significance of the Sessile Way of Life

The Role of the Polymerization and of Subsequent Oligomerization during the Phylogeny

The Validity of Watson's Rule for the Invertebrates

Chapter 2. The Previous Interpretations of Cnidaria

The Origin of Cnidaria

The Right Sequence of the Cnidaria Groups

Why is there no Medusa Form in Anthozoa?

The Primarily Solitary Polyps Appear in Anthozoa only

Polymorphism Has Reached Its Climax in Hydrozoa

The Regressive Development of the Intermediate Layer in Cnidaria

The Morphologic Proofs of the New Interpretation of the Phylogeny of Cnidaria

Muscular Tissue

The Nervous System

The Emunctory-Excretory Organ

The Genital System

The Alternation of Generations in Cnidaria

The Digestive System

The Skin and Cnidae

Ontogeny (the Development of the Embryo)

Asexual Reproduction and the Regeneration

The Endosymbiotic Mononuclear Algae

Chapter 3. The Consequences of the New Interpretation of Cnidaria

The New System of the Cnidaria

The Rank and the Position of Cnidaria in the Animal System

Discussion of the New Interpretation of the Evolution of Cnidaria

The Probable Origin of Cnidaria

The Larvae of "Cnidaria"

A Comparison of Cnidaria Larvae with Other Larvae

The Origin of the Turbellaria

The Origin of the Acoelous Turbellaria

The Relationship between Conjugation and Copulation

The Point of Separation of the Evolutions of Infusoria and Eumctazoa

The Origin of the Complex, Hypercellular Individualities

Is the Plasmodial State of the Acoela a Primary Element?

An Attempt to Reconstruct the Initial State of the Eumetazoa

The Origin of the Middle Body Layer of the So-Called Mesoderm

Two Difficulties of the Theory of Polykaryonts

Can Cleavage be Really Considered as a Proof of the Colonial Theory?

The Basic Principles that should be Used in a Reform of the Whole Animal System

Evolution Generally had a Progressive Trend

Chapter 4. The Classification of the Animal World and the New Genealogical Tree

General Premises

The Limit between the Plant and the Animal Worlds

The System of the Protozoa

The Transition from the Protozoa to the Metazoan State

There Are No Well-Warranted Mesozoa

The Classification of Metazoa

The Parazoa as an Independent Subregnum

The Eumetazoa and their Subdivisions

The Elimination of the Terms Coelenterata-Coelomata

The Coelomata as a Taxonomic Unit

The First Phylum of the Eumetazoa: The Ameria

The Transition from the Amerous to the Polymerous State

The Problem of Justification of the High Taxons: Protostomia-Deuterostomia

The Classes of the Polymeria

The Phylum Oligomeria and Its Classes

The Sphere of the Phylum Oligomeria

The Problem of the Inclusion of the Sipunculida into the Phylum Oligomeria

The Oligomeria as the Initial Form for the Evolution of the Chordonia

The Fourth and the Last Phylum of the Eumetazoa: Chordonia

The Probable Origin of the Chordonia

A Comparison of the Present Attempt to Derive the Chordonia from the Ancestral Form Resembling the Present Day Enteropneusta with the Similar Attempt Made by Hans Steiner

The Genealogical Tree of the Chordonia

The Genealogical Tree of the Entire Animal World

An Attempt to Unify the Animal System

Bibliography

Index