150 
BRITISH ENTOMOSTRACA. 
in a place of security, that it cannot be displaced by any 
agitation of the water, and is occupied twelve hours in 
the operation. The eggs remain about four days and a 
half before they are hatched, and then the young at once 
assume the appearance of the perfect animal, though 
varying a little in shape of shell. According to Jurine 
they undergo several moultings before they are fit to pro- 
create their species; the frequency of these moultings 
depending upon the season of the year, and being in 
proportion to the gradual development of the animal. 
Moulting continues to take place in the adult after each 
laying, and as the shells of these little animals get very 
frequently covered with dirt and moss, which adhere close 
to them, this change of covering becomes a useful act to 
disembarrass the animal of a shell now disagreeable to it ; 
while in the young, their development can only take place 
by getting rid of the shell as soon as it becomes too small 
for the body contained within. The renewing of the 
shell forms a fine example of the process of exuviation, as 
naturalists term it. The change which takes place being 
most complete ; for not only does the shell itself fall off, 
but the animal even casts off the internal parts of the 
body, the fine pectiniform branchiae, and the minutest 
hairs clothing the setae of the antennae, &c. 
The food of these little creatures consists of dead animal 
matter, Confervae, &c. Straus says he never saw them 
attack living animals when they were well and strong, but he 
has frequently seen them attack worms, &c., when wounded 
and weak. Though dead animal matter was their choice, 
they will not, he adds, eat it when putrid. They no doubt 
also prey on each other, as I have often observed indivi- 
duals of one species devouring eagerly the dead carcases 
of species different from themselves. When the ponds and 
ditches in which they live, dry up in summer, they bury 
themselves in the mud, and thus preserve their lives as 
long as the mud retains any moisture, becoming active as 
ever when the rain falls and again overflows their habita- 
tions. After long-continued drought, however, when the 
