616 Recent Literature. [ September, 
or ten days from the escape from the egg, these favored few were 
fifty per cent. larger than their weaker comrades who were born 
upon the same day. Their mouths had by this time increased so 
much in size that they were no longer satisfied with nibbling off 
the gills of their brethren, but now began to swallow them bodily. 
This great increase in the supply of food soon produced a marked 
effect upon those who were-thus supplied; so that in ten days 
from the time that they began to feed in this way they were from 
ten to twelve times the length and bulk of those upon whom they 
were feeding. Developing at this rapid rate; they arrived at the 
stage when the gills are re-sorbed and the abranchiate form leaves 
the water for the marshy land or old, damp log, where it usually 
. makes its home and where it would find a supply of more natural 
food-material. 
Here then was a very interesting case of natural selection, by 
survival of the fittest. All the weaker individuals being destroyed 
and actually aiding the stronger ones by serving them as food 
until they could pass through their changes and escape to other 
-regions where food was more abundant. 
cH 
RECENT LITERATURE. 
-FLOGEL ON THE STRUCTURE OF THE BRAIN IN DIFFERENT OR- 
DERS OF InsEcts.—The Supplementary Heft for May 28th of 
Siebold and Kolliker’s Zeitschrift fiir Wissenschaftliche Zoologie 
-= contains an elaborate article by J. H. L. Flogel, illustrated by a 
number of micro-photographs. This and Dietl’s excellent paper, 
published in 1876, are the only treatises on the minute structure 
of the brain of insects, Owskianikof having studied that of the 
spiny lobster (Palinurus) several years ago, while Dietl studied 
the brain of Astacus. Flogel establishes three points as the re- 
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