558 
segments, inclosed in their proper skin, were 
now more elongated and very much en- 
larged, and the new segments were further 
developed as well as the germinal membrane. 
The external tegument was more extensively 
separated from the whole body, especially at 
the erior and the head was retracted 
within it “and bent on the under part of the 
thorax. It was thus evident that this tegu- 
ment was not of recent formation, that it 
simply enclosed the animal as the whole had 
been previously enclosed in the amnion, as is 
proved by the circumstance that it extended 
smoothly over the whole body, antenne and 
legs, and did not follow the inflection or redu- 
lication of the proper surface of the animal 
ike the true skin beneath it, but passed di- 
rectly over the segments, and was simply pro- 
truded or distended by the growth of parts be- 
neath, as in the instance of the new legs (6). 
Up to this period, therefore, observes Mr. New- 
port, the young Julus must still be regarded as 
in the embryo condition, although for a day or 
two after bursting the amnion, it possessed 
the power of locomotion and evinced some 
developement of instinct. At its next change 
of skin, when it enters what Mr. Newport 
regards as the fourth period of its developement, 
and when it has acquired fourteen pairs of 
legs, it assumes for the first time a condition 
analogous to the larva state of true insects on 
bursting from the ovum; the difference be- 
tween the two being that the analogue of this 
tegument of the embryo in insects is slipped off 
at the bursting of the amnion on leaving the 
shell, while that of the Myriapod is not thrown 
off until some days after it has entirely left the 
ovum. This embryo condition of the animal 
will therefore explain the circumstance of its 
first acquiring a pind ete] of locomotion, and 
then remaining perfectly quiescent without 
taking food to prepare for this change—the 
third period of its embryo life. 
The lower portion of the alimentary canal is 
at this time distinctly visible through the new 
segments, exhibiting a corrugated or folded ap- 
ce, an arrangement doubtless intended to 
allow of its sudden extension at the period of 
throwing off the skin and elongation of the seg- 
ments. The colon is of a very dark colour and 
exhibits its thickened peculiar structure with 
its longitudinal muscular bands. Around its 
posterior part, Mr. Newport observed an 
tion of what app: to be globular cells. 
ey seemed to be part of the organs of gene- 
ration in the course of developement. At first 
they were regarded as hepatic vessels, but this 
Mr. Newport considers could hardly be the 
case from the fact that each of these organs 
directly enters the canal as a straight vessel, but 
they might be vessels folded up to be unfolded 
suddenly, as in the case of the alimentary canal. 
By the twenty-sixth day the young Julus 
casts off the covering in which it had hitherto 
been infolded, and enters the fourth period of 
deve , having now seven pairs of legs 
and fi segments to its body (, Ae. 324). 
In this condition the antennz were found to 
have become elongated by at least one-third of 
MYRIAPODA. 
joints. 
their original length, and exhibited six distinet 
e eye still consisted ofa single ocel- 
lus, but this was now surrounded bya darker 
coloured portion of the tegument. The new 
I ¢ 
legs (bc) were equal in size and length to # 
original ones, but were evidently more fe 
The transverse markings on the seven 
segments (2-7) were very distinct, and t 
brown patch on the seventh segment was mt 
darker in colour. The whole body of thea 
mal was considerably elongated. This ° 
produced chiefly by the extension of thet 
segments (7 g) formed by the germinal m 
brane at the p agese>: part of the sevent »t 
which, in the early part of the last peri 
seemed to form a single distinct segment 
vered by the common tegument. ; 
anterior of these segments (8), now the 
of the whole body, had uired an @ 
equal on its upper surface to the p ; 
ment, but was shorter on its ventral suri 
Like the preceding original segments it 
divided into two regions by a transve' 
pressed line. The next segment in 
to this, the ninth, had also become enlar 
about one-third of the size of the eighth, 
was, like it, marked transversely. The 
four segments were each more developed 
in the preceding state, but not to so gt 
extent as the others. The two 1g 
ments (14 15), the penultimate and anal 
undergone no change. They had simp 
quired a little extension at the apex of the 
ment, and were now covered with a fes 
tered hairs. It is thus proved that the be 
elongated, not by the division of the” 
formed segments into others, but always t 
formation of new ones in the 
brane that extends from the posterior 
the antipenultimate segment to the per 
which last segment, with the anal, underg 
change. That segment is always furthe 
vanced in growth which is immediately 
rior to the last segment that possesses 
then the next in succession, until we 
the terminal ones—the penultimate 
anal—that never possess legs. = 
By the forty-fifth day more new segm 
had evidently been developed by the gern 
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