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MEMOIRS OF
THE CONNECTICUT ACADEMY
OF ARTS AND SCIENCES
VOLUME VII DECEMBER, 1920
The Appendages, Anatomy, and Relationships
of Trilobites
BY
PERCY E. RAYMOND, Ph.D.
ASSOCIATE PROFESSOR OF PALAEONTOLOGY, AND CURATOR OF INVERTEBRATE
PALAEONTOLOGY IN THE MUSEUM OF COMPARATIVE ZOOLOGY,
HARVARD UNIVERSITY
NEW HAVEN, CONNECTICUT
PUBLISHED BY THE
CONNECTICUT ACADEMY OF ARTS AND SCIENCES
AND TO BE OBTAINED ALSO FROM THE
YALE UNIVERSITY PRESS
THE TUTTLE, MOREHOUSE & TAYLOR COMPANY
TO THE MEMORY OF
CHARLES EMERSON BEECHER
SKILLFUL WITH HAND, BRAIN, AND PEN; REVEALER OF THE MYSTERIESOF TRILOBITES;
THIS MEMOIR IS DEDICATED
FOREWORD.
By CHARLES SCHUCHERT.
Trilobites are among the most interesting of invertebrate fossils and have long attractedthe attention of amateur collectors and men of science. These "three-lobed minerals" havebeen mentioned or described in books at least since 1698 and now several thousand speciesare known to palæontologists. To this group of students they are the most characteristicanimals of the seas of Palæozoic time, and even though they are usually preserved as dismemberedparts, thousands upon thousands of "whole ones" are stored in the museums ofthe world. By "whole ones" perfect individuals are not meant, for before they becamefossils the wear and tear of their time and the process of decomposition had taken away allthe softer parts and even most of the harder exterior covering. What is usually preservedand revealed to us when the trilobites weather out of the embrace of their entombing rocksis the test, the hard shell of the upper or dorsal side. From time to time fragments of theunder or limb-bearing side had been discovered, first by Elkanah Billings, but before 1876there was no known place to which one could go t