Chapter III— MOLTING AND GROWTH. 
EARLIER OBSERVATIONS 
Tlie process of molting, which, makes growth possible to the arthropod, is of such 
interest and importance that it deserves very careful attention. There is much to be 
added to our knowledge of this subject in the lobster, and I shall deal with it at 
full length. Aristotle knew very well that crabs and lobsters shed their shells (The 
History of Animals, Book vm, c. xix), although his observations were not accurate; 
but the fact was forgotten and finally denied altogether. 
It is only necessary to go back to the beginning of the last century (in 1712) to 
find Reaumur ( 161 ) demonstrating that the river crayfish periodically cast its shell, 
yet in the early part of the seventeenth century, a hundred years before, Olaus 
Wormius, according to Couch ( 47 ), speaks of the molting of crabs as a thing not to 
be doubted. 
The regeneration of the lining of the stomach of the crayfish was reported by 
Van Helmont, but this writer’s reputation did not lend much weight to the statement 
until it was confirmed in 1709 by Geoffroy ( 74 ). 
To that marvelously acute observer, Reaumur, we are indebted for the best account 
of the exuviation of the crayfish. He took crayfishes which appeared to be ready to 
molt and placed them in jars of water in his museum and watched them carefully. 
Others he put into boxes, the bottoms of which were pierced with holes, and moored 
them iu the river Marne, which flowed past his garden. The crayfishes in the river 
were under more favorable conditions than those kept in the house, and molted more 
frequently in consequence. He gives a very circumstantial account of the external 
process of molting in the crayfish, which took place in June, July, and August. The 
time occupied in the final act of casting the shell by crayfishes kept in the river was 
from seven to fifteen minutes, while those iu the house often struggled for several 
hours before they were free. Sometimes they died in the operation, especially the 
young ones. Some would lie on their sides, some on their bellies or backs, and in the 
latter case he observed that they frequently died. 
However, as Couch remarked, Reaumur’s paper produced so little effect that 
when, many years later (1750), Peter Collinson communicated some cursory remarks 
on this subject to the Royal Society, his account of the molting of the crab was received 
with so much doubt that his second paper was chief! y employed in furnishing evidence 
of the fact. 
Observations on the molting of the higher Crustacea have since been made by 
Couch ( 45 , 46 , i7),Gosse ( 81 ), Chantran ( 37 ), Max Braun ( 22 ), Vitzou ( 197 ), Sars(776j, 
Hyatt ( 104 ), Brook ( 26 ), and others. The histological changes involved in the molting 
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