CYCLOPID^E. 
195 
itself support ; it then, by moving its limbs and shaking 
the valves of the shell, the new parts at the same time 
coming forward, loosens the old covering, and in a short 
time frees itself from the exuviae altogether, leaving behind 
the sheaths of the limbs, hairs, plumes, and even the minute 
setulae, that almost escape the power of the microscope 
itself from their fineness, such as the delicate plumose 
setae which adorn the filaments of the tail. “ How far 
beyond all idea this most subtle fineness !” says Muller, 
from whom I have taken this description ; “ for they are 
sheaths containing other smaller sheaths, which again in- 
clude other organs smaller still.”* 
The number of times they moult during life is not 
known ; but Jurine says, they ordinarily, though not 
always, moult before each time of laying eggs. They cer- 
tainly do not always do so ; and perhaps the frequency of 
their moulting may depend much upon the temperature, 
the season, &c. 
Having the experiments of Spallanzani and others, 
upon the reproduction of mutilated members in various 
animals, in his eye, M. Jurine instituted a series of expe- 
riments upon the Cyclops quadricornis , to see how far this 
power existed in this family. In his first attempts he 
failed, the animals having died before they moulted, and 
without showing any evident change in the mutilated 
members. At length, however, he succeeded. He cut 
off about two thirds of an antenna in a female, which 
lived and moulted, reappearing after moulting, with 
beautiful, perfect, new antennae, the old one of the cast 
shell not having shown the least indication of a change, f 
Some authors have asserted that these insects possess a 
wonderful power of resisting drought, and that when, by 
reason of the summer heats, the marshes become dried up, 
the little creatures do not die, but as soon as the mud is 
again moistened by the rain, they recover entirely. Jurine 
doubted this, and commenced a course of observations to 
* Entomost., p. 9. 
f Hist, des Modoc., p. 40. 
