324 THE AMERICAN NATURALIST. [Vor. XXXIV. 
they pass through the narrow meshed regions they assume a corre- 
sponding slender form, to expand later in the wider rings in the 
region of wider meshwork. The chromosomes are collections of 
chromatic granules which are arranged on the walls of the meshes, 
hence they outline a figure corresponding to the shape and size of 
the mesh. All this, the author concedes, would lend itself to the 
idea that we are dealing with an alveolar or vesicular structure. 
The formation of new cell walls by the thickening and fusing of 
strands of the framework is apparently similar to the mode of mak- 
ing cell walls in the cleavage of echinoderm eggs as described by 
G. F. Andrews. And the conception of chromatin granules moving 
along strands of protoplasm, as do granules in the pseudopodia of 
rhizopods, is also the same as the flowing or filose movements there 
described for the interalveolar plasma in various animal tissues and 
eggs. Considerable space is given to the description of remarkable 
amoeboid movements performed by the cells of the blastoderm ; they 
may send out very long finger-like pseudopodia which are at first 
chiefly clear Hyaloplasma but may become granular and be with- 
drawn. "These activities, however, are not known in the normal state, 
but seem to be called forth by the stimuli that come to the blasto- 
derm, when removed to a compressorium for observation. Among 
other interesting observations we will mention only the occurrence 
of multiple asters in eggs that had not been fertilized, a phenomenon 
similar to that observed by T. H. Morgan? in echinoderm eggs. 
The unfertilized eggs of the salmon may be kept in running water 
for weeks without losing life. In the rainbow trout, also, unfertilized 
eggs were not dead at the end of several weeks. 
Sections of such eggs kept seventeen days show numerous asters 
in which the radiating lines connect with a rather uniform mesh of the 
morphoplasm or else with the rays of other asters. At the center 
of each aster is a group of granules, representing the centrosome. 
E. A. A. 
Embryology of Invertebrates.*— The first part of the original 
German edition of Korschelt and Heider's Embryology of the Inverte- 
brates appeared in 1890, and the last part in 1893. The translation 
1 The Living Substance. Journ. of a Supplement 1897. 
2 The Action of Salt Solutions, etc. Roux’s Archiv, Bd. viii, 1897. 
3 Korschelt, Dr E. and Heider, Dr. K. Text-book of the Embryology of 
Invertebrates. Vol. i translated by E. L. Mark and W. M. Woodworth; vols. ii ' 
and iii translated by M. Bernard and revised and edited by M. F. Wood 
The Macmillan Company. 
