iN 
Reviews—The Structure of Trilobites. HAL 
But these defects are no part of Mr. Greenly’s work, and it remains 
to congratulate him upon an absorbing account of a very remarkable 
achievement. We understand that he has lost no time in trans- 
ferring his attention to the Carnarvonshire mainland, and we await 
with eager interest the results of his work in that equally classic area. 
CaN: 
THe APPENDAGES. ANATOMY, AND RELATIONSHIPS OF TRILOBITES. 
By Percy E. Raymonp. Memoirs of the Connecticut Academy 
of Arts and Sciences. Vol. VII. 1920. 169 pp., 11 plates and 
portrait, text-figs. 
HE researches of the late Profesor C. E. Beecher on the structure 
of Trilobites are familiar to all paleontologists, and his 
- restorations have beea widely copied in textbooks. It is perhaps 
not generally known that his writings on the subject were all 
preliminary to an extensive monograph on which he was engaged 
up to the very day of his death in 1904. The materials for this 
monograph, as he left them, comprised a large number of specimens 
carefully developed, and photographs and drawings of these, but 
no written notes. At the invitation of Professor Schuchert, who 
succeeded him in the chair of paleontology at Yale, one of Beecher’s 
pupils, Professor Perey EH. Raymond, of Harvard, has taken up the 
anfinished task, and in this volume, dedicated to the memory of his 
master, gives the results of his study of the material, illustrated 
largely by fine reproductions of Beecher’s own photographs and 
drawings. 
In a foreword by Professor Schuchert some interesting details 
are given of Beecher’s methods of work. The pyritized specimens 
of Triarthrus, from the Utica shale of Rome, New York, which 
provided the main subjects of investigation, are as a rule less than 
an inch long, and the cleaning of the minute details of their 
appendages was a difficult and tedious business. After various 
chemical methods had been tried without success, it was found 
best to depend on abrasives (carborundum, emery, and pumice) 
applied with pieces of rubber. As development went on, the rubbers 
were reduced in size so as to abrade only minute areas. The beautiful 
photographs reproduced in this volume were taken by immersing 
the specimens in liquid Canada balsam and photographing through 
a cover-glass with a vertical camera. 
Although the primary object of this memoir is to give detailed 
descriptions and figures of Beecher’s material, the author has also 
re-examined most of the known specimens of Trilobites exhibiting 
the appendages. In particular he has studied the material worked 
out by Dr. Walcott, whose help in the communication of specimens 
and photographs is acknowledged, and he discusses at length the 
various problems connected with the morphology, phylogeny, and 
bionomics of the group. The monograph, therefore, covers much 
the same ground as that of Dr. Walcott, reviewed in this Magazine 
