182 The American Geologist. March, 1a 
Ohio State University, and Mr. Charles Schuchert uses it in arrang- 
ing the Harris collection of Cincinnati fossils in the United States 
National Museum at Washington, and has placed a copy as a guide 
for visitors who wish to examine that collection. Siae 
Studies in Evolution; mainly reprints of occasional papers selected 
from the publications of the laboratory of invertebrate paleontology, 
Peabody museum, Yale University, by CuHartes Emerson Breecuex 
New York Charles Scribner’s Sons; London, Edward Arnold 
1901. $5.00. 
This work is one of the Yale bicentennial publications, dedicated to 
the graduates of the University. It contains 440 pages and 34 plates 
and concludes with an excellent index. It is a republication of the 
principal papers of Dr. Beecher selected from various sources bearing 
on the development of some of the invertebrate animals, and 
on certain features of organic evolution. The author's earliest 
paper on the development of fossil brachiopods was prepared 
jointly with J. M. Clarke, of Albany, and it may be considerea 
as one of the first steps amongst American paleontologists toward the 
systematic study of the progressive changes of fossil invertebrates. Wal- 
cott, Ford and Matthew had done similar work with some species of 
trilobites and Hyatt had described and illustrated some of the pro- 
gressive characters of cephalopods. Morse alone (or almost alone) of 
American paleontologists had studied some of the early stages of 
brachiopods (Terebratulina) as early as 1873, but those studies were 
partial and more or less fragmentary, owing to the lack of a large sup- 
ply of specimens, whose stratigraphic and geographic origin was known. 
At Albany such material was found, in the collections and laboratories 
of Prof. James Hall. This paper is placed No. 4 in the series devoted 
to the development of the Brachiopoda. It is preceded by papers that 
treat of more general principles, such as the genesis of the brachiopodal 
parts, the stages of growth and decline, the morphology of the brachia, 
correlations of ontogeny and phylogeny, and by a revision of the fami 
lies of loop-bearing Brachiopoda. It is followed by the paper on the 
development of Bilobites, that on the development of Terebratalia obso- 
leta Dall, and by that on the development of the brachial supports in 
Dielasma and Zygospira. 
The opening paper of the volume is that on the origin and cendite 
cance of spines, a discussion which by its completeness and symmetry 
will long stand amongst the American classics of evolution. 
“Just as all the features of terrestrial topography are included be- 
tween the limits of plains and mountains, and the mountains are con- 
sidered as the limit of progressive accidentation, so the spines of ani- 
mals or the monticules and pinacles of their surface may be considered 
as the limits of progressive differentiation. The primitive base-level, 
or peneplain, becomes elevated, and by erosion is cut up into tablelands, 
mesas, and buttes, with intersecting valleys. The valleys are 
ee 
