126 
MR. NEWPORT ON THE ORGANS OF REPRODUCTION, 
body, and from the interior of the colon. To effect this, the animal, which has pre- 
viously been lying coiled up in a circular form, first straightens its whole body ; it 
then forcibly contracts and shortens its body, especially at the posterior part, and by 
this means becomes greatly enlarged in bulk at its middle portion, but smaller at its 
extremities. During these efforts, which are some of the most powerful it is able to 
make, the skin becomes loosened from its posterior parts, and while still contracting 
its segments, the anal extremity, and with it the lining of the colon, become entirely 
detached, and from these it gently withdraws itself within the old skin in which the 
body is incased, as from the finger of a glove. This is precisely what takes place in 
the shifting of the skin in insects. Having effected this part of its labour, all the 
posterior segments are again shortened, the animal again disposes itself in a circular 
form, and after repeated exertions succeeds in bursting the tegument of the head in 
the part just described. As in the case of true insects, the young lulus entirely 
empties the alimentary canal by voiding its faeces, and ceasing to eat for one or two 
days preparatory to undergoing each transformation. When examined immediately 
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 legs requiring time for further development before the old skin is thrown off. 
When these changes have been effected, the animal again arranges its legs along 
the ventral surface of the body, and coils itself up in a circular form, in which state 
it remains for several hours, often with the skin partially covering the posterior seg- 
ments. In these transformations, as in those of insects, the whole of the structures 
undergo alteration ; the lining membrane of the colon and lower intestines comes 
away attached to the posterior, as that of the mouth and oesophagus does to the ante- 
rior part. It is not, therefore, by the bursting of the skin on the under surface of the 
anterior segments that the change is effected, as stated by Waga, but by a separation 
of the natural sutures of the covering of the head. Indeed it is almost impossible to 
conceive how the legs of the thorax and covering of the mandibles could be thrown 
off if the change took place as stated by Waga. 
It has been supposed that the lulus devours its cast skin, as is done by some larvse 
of insects. I certainly have seen it nibbling at the skin some hours after the change, 
but although there were several cast skins in the vessel, and no food, there seemed 
no disposition on the part of the animal to devour it. 
The fifth period of development being now attained, the young lulus has three ocelli 
on each side of the head, seven joints to the antennae, thirty-four legs, and twenty- 
one segments to its body. 
On the forty-eighth day (fig. 21.) the young lulus has entered this period, and ex- 
hibits a marked alteration in its appearance. The antennae 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 length of these organs has been increased 
chiefly by the elongation of the second basilar joint, which is now narrower and 
