— one 
organs find their out- 
let, a circumstance 
lier changes of the 
_ duction of new seg- 
the segment imme- 
from: the fact that 
MYRIAPODA. 
is thrown off that the new segments become 
elongated, and the Julus then appears suddenly 
to have acquired six new divisions to its body. 
The production of new legs is equally cu- 
rious. Up to the present period the animal 
has but six legs (fig. 322, 6 a), but four addi- 
tional 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 (0 ¢ ), 
four on each, covered by the common tegu- 
ment, which, we have seen, is becoming deci- 
duous. The three single pairs of legs that now 
exist as the only locomotive organs are attached, 
pair to the prothorax or second segment, 
one to the third and one to the fifth segment. 
The fourth, or segment intermediate between 
these last, never possesses any legs, but in the 
female contains the outlets of the organs of ge- 
 neration. The general appearance of the ani- 
_ mal has now become less delicate, the head has 
uired a darker colour, and a faint broad 
patch (fig. 322, p) is now making its appear- 
ance at the anterior partof the seventh seg- 
ment. This patch, 
which is permanent 
through all the ear- 
Fig. 322. 
animal, is of the 
greatest utility in de- 
termining the pro- 
ments. It is in 
diatel sterior to 
this a. the male 
the more remarkable 
this outlet is in the anterior part of the 
Original germinal space, and at the bursting 
of the egg this is very near the termination 
of the body. Such was the condition of 
the young Julus one hour after leaving the 
amnion. It soon began to exhibit its animal 
powers, to shew the instincts peculiarto its 
Species, and to be sensibly affected by ex- 
_ ternal causes. In less than six hours from the 
very slowly but with instinctive care. 
bursting of the amnion the little creatures were 
in motion. 
At first the antenne were the or- 
gans employed. They were moved slowly to 
and fro, and seemed to gain power by use. 
‘Tn a short time the limbs began 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 em- 
bryos crawled slowly about, but moving the an- 
tenne briskly. On exposing them to a strong 
light a marked effect was produced in their 
movements. They evidently were greatly af- 
Te by it, and seemed instinctively to shun 
it. This was the first marked exhibition of 
instinct. Locomotion was at first performed 
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 pro- 
557 
leg, and its step, as it were, measured, its body 
was carried forwards by at. effort that extended, 
as in insects, from segment to segment. 
At twenty-four hours after escaping from 
the amnion the young animals were lying toge- 
ther in a heap, but when disturbed seemed to 
have acquired more power of moving: they 
remained quiet except when aroused, and had 
not yet taken food. The only marked diffe- 
rence in their appearance, excepting that they 
had still further increased in size, was in the 
nipple-shaped protuberances on the sixth and 
seventh segments, the rudiments of future legs. 
These were now more distinct and mammiform. 
Ten hours later in the day they assumed still 
more the appearance of nipples projecting from 
the under surface of the segments. When 
examined in specimens that had been placed in 
spirits of wine, it became evident that these 
projections were occasioned by the develope- 
ment under the deciduous tegument of four 
new, but exceedingly minute legs, complete in 
all their parts, each covered by its proper skin. 
The claws to the legs of the other segments 
were also more strongly marked. The new 
segments (f) were more developed, although 
still covered by the common tegument, and, as 
in the preceding state, forming only one divi- 
sion of the body, while a small space behind 
them indicated the point from which other new 
segments were to be produced. 
On the nineteenth day, Mr. Newport found 
that the animals had acquired a little darker 
colour, but were still remaining quiet in their 
cells, and did not appear to have taken food. 
The enlargement of the body had not extended 
to the prothorax, which did not increase in size 
in proportion to the rest. The double pairs of 
new legs to the sixth and seventh segments 
were now distinctly visible through the exter- 
nal tegument, which had begun to be separated 
from the under surface of the old segments, to 
which up to this period it had closely adhered. 
The patch on the side of the seventh segment 
had become darker, and the new segments 
were further advanced. 
On the twenty-first day (fig. 323) the young 
Juli still remamed coiled up and _ perfectly 
quiescent, with their 
legs disposed side by 
~, side along the under 
YA surface of the body, like 
/ the pupe of Lepi- 
J dopterous Insects. The 
new legs had consider- 
ably increased in size, 
as well as the whole 
animal, although it had 
not taken food. The ani- 
mal was still. partially 
coiled up, but the skin 
that covered its body 
was greatly distended, 
more especially along 
the ventral surface. It 
was less able to move 
than before, the period 
of throwing off this skin being fast approach- 
ing: the double legs of the sixth and seventh 
