‘membrane, soon to be exposed by another 
change of skin that was about to take place. 
The Julus ceased to eat, became torpid, 
and lay coiled up in a spiral form. The 
ment of the body began to assume a 
whitish crustaceous appearance, and the ani- 
mals secreted themselves beneath any dry co- 
vering, but avoided parts too wet. The princi- 
oq changes in their general appearance were in 
_ the eyes, each ocellus being much more dis- 
tinct, and in the germinal space, which was 
developed to its greatest extent, and distinctly 
exhibited the six new segments. 
_ The change of skin, according to Mr. New- 
is effected in the following manner. The 
_ young Julus, when about to cast its integu- 
_ ment, bends its body in a semicircular form, 
with its head inflected against the under sur- 
face of the second segment. In this condition 
‘it remains for several hours with its legs widely 
arated and the dorsal surface of the segments 
ended. The head is then more forcibly 
bent on the sternum, and a longitudinal fissure 
takes place in the middle of the epicranium, 
_and is immediately extended outwards on each 
‘Side posteriorly to the antennz in the course of 
other sutures, the analogues of which Mr. 
Newport has described as the triangular and 
picranial sutures. Through the opening thus 
rmed in its covering the head is then carefully 
ithdrawn, and with it the antenne and parts 
the mouth, and afterwards the anterior seg- 
nts and single pairs of legs. The first and 
arently the most difficult part of the shed- 
g of the skin is its detachment from the 
terior segments of the body and from the 
; ior of the colon. To effect this the ani- 
tal, which has been previously lying coiled up 
im a circular form, first straightens its whole 
body; it then forcibly contracts and shortens 
: tself, especially at the posterior part, and by 
3 means becomes greatly enlarged in bulk 
its middle portion, but smaller at its extre- 
ties. During these efforts, which are some 
the most powerful it is able to make, the 
__ Skin becomes loosened from its posterior parts, 
__ and while still contracting its segments, the 
extremity, and with it the entire lining of the 
_ Golon, become completely detached, and from 
5 
} 
_ these it gently withdraws itself within the old 
4 in whicn the body is encased as from the 
er ofa glove. This is precisely what takes 
in the shifting of the skin in insects. 
ng effected this part of its labour all the 
erlor segments are again shortened; the 
mal once more disposes itself in a circular 
and after repeated exertions succeeds in 
ursting the tegument of the head in the part 
ust described. As in the case of true insects 
the young Julus entirely empties the alimentary 
al by voiding its fceces and ceasing to eat 
one or two days preparatory to undergoing 
h transformation. When examined imme- 
diately before the change there are no other 
Symptoms of new legs than slight elevations of 
the skin, and this perhaps accounts for the 
length of time occupied in the change, the new 
| Jegs requiring time for further developement 
before the old skin is thrown off. 
Having cast its skin and thus attained the 
MYRIAPODA. 
559 
the young Ju- 
on each side 
fifth period of developement, 
lus (fig. 325) has three delli 
Fig. 325. 
Fig. 326. 
of the head, seven i 
joints to the antenna, 
thirty-four legs, and 
twenty-one segments 
to its body. On the 
forty-eighth day this 
has been accomplished, 
and the young Ju- 
lus exhibits a marked 
alteration in its ap- 
pearance. The an- 
tennz are considerably 
longer than the head, 
with seven distinct 
joints, and, as in the adult, the apical one 
is short and inserted into the sixth. The single 
eye has disappeared, and in its stead three 
distinct ocelli, arranged in a triangle, have 
been developed. The new segments of the 
body produced at the former change of the 
animal, from the eighth to the twelfth in- 
clusive, (8—12,) are now of the same size as 
the original ones, and each has developed 
from it two additional pairs of legs, so that 
the whole number of legs is now thirty-four. 
The thirteenth, or, if we may so name it, 
germinal segment of the last period, is less de- 
veloped than the preceding ones, and is distin- 
guished from them by the circumstances that it 
is smaller, possesses no legs, and has no lateral 
