This book provides a comprehensive scientific report on the pycnogonids, a group of marine arthropods found across the globe. The report is based on specimens collected during the scientific expedition of HMS Challenger, one of the most significant scientific voyages of the 19th century. This book will be of interest to marine biologists, zoologists, and anyone interested in the history of scientific discovery. 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.