118 
MR. NEWPORT ON THE ORGANS OF REPRODUCTION, 
cumstances explain the cause of the very quiescent state of the young lulus, and its 
almost, and perhaps entire abstinence from food while this skin remains on its body. 
It is not until this skin is thrown off that the new segments become elongated, and 
the lulus then appears suddenly to have acquired six new divisions to its body. The 
production of new legs is equally curious. Up to the present period the animal has but 
six legs (6. a). But four additional pairs are nevertheless in the course of formation. 
These at present exist only as eight minute nipple-shaped prominences on the under 
surface of the sixth and seventh segments (b, c ), four on each, covered by the common 
tegument, which we have seen is becoming deciduous. The three single pairs of legs 
that now exist as the only locomotive organs, are attached, one pair to the protho- 
racic or second segment, one to the third, and one to the fifth segment. The fourth, 
or segment intermediate between these, never possesses any legs, but in the female 
contains the outlets of the organs of generation. In pursuing the analogies between 
these segments and the thorax of insects, the first two seem to represent the pro- and 
mesothorax, while the fourth and fifth becoming united, answer to the metathorax : 
this is analogous to the fusion of the fourth and fifth segments in the changes of true 
insects. The general appearance of the animal has now become less delicate, the 
head has acquired a darker colour, and a faint broad brown patch ( p ) is now making 
its appearance at the anterior part of the seventh segment. This patch, which is 
permanent through all the earlier changes of the animal, is of the greatest utility in 
determining the production of the new segments. It is in the segment immediately 
posterior to this that the male organs find their outlet, a circumstance the more re- 
markable, from the fact that this outlet is in the anterior part of the original germi- 
nal space, and that at the bursting of the egg this is very near the termination of the 
body. This was the condition of the young lulus one hour (fig. 10.) after leaving the 
amnion. It soon began to exhibit its animal powers, to show the instinct peculiar to 
its species, and to be sensibly affected by external causes. In less than six hours from 
the bursting of the amnion, those specimens which had first undergone the changes 
were in motion. At first the antennae were the organs employed. They were moved 
slowly to and fro, and seemed to gain power by use ; in a short time the limbs be- 
gan to be extended, and the animal slowly raised itself upon them for the first time. 
Its first efforts at locomotion were exceedingly feeble, but it gradually gained 
strength. At the end of twelve hours the whole of the embryos were in motion, 
crawling about slowly, but moving the antennae briskly. On exposing them to a 
strong light, a marked effect was produced in their movements. They evidently were 
greatly affected by it, and seemed instinctively to shun it, retiring out of the way. 
This was the first marked exhibition of instinct. Locomotion was at first performed 
very slowly, but with instinctive care. The anal segment previously to each step was 
expanded like the anal leg of the larva of an insect, and being first attached like a 
true proleg, and its step, as it were, measured, its body was carried forwards by an 
effort that extended, as in insects, from segment to segment. 
