This monograph by Harley Jones Van Cleave describes the taxonomy and morphology of several species of acanthocephalans, a group of parasitic worms that are of interest to biologists and veterinarians. The author provides detailed illustrations and comparisons with related taxa, as well as ecological and distributional data. This book will appeal to specialists in invertebrate zoology and parasitology. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.