the circumstance that it is at this part of the 
body that the future new segments are to be 
produced. 
On the fourth day, Mr. Newport first ob- 
served some faint traces of a single eye, or 
ocellus, on each side of the head. The embryo 
had now further increased in size, and the ru- 
diments of its future legs had become larger 
and more obtuse, an appearance which the 
newly-formed limbs of the Articulata often 
exhibit previously to their further elongation. 
Traces of the formation of internal organs were 
now evident through the tegument at the pos- 
terior part of the body, and the funis was con- 
tracted as if about to separate. Internally the 
body was still formed of cells aggregated toge- 
ther, but differing more in size than at any 
revious period, as if they were becoming 
used into separate tissues, and in the midst 
of them and closely surrounded on all sides 
was the newly-formed alimentary canal. The 
canal was now more opaque, and when pressed 
‘out of the body more firmly adhered together 
_ than any other internal structure, and was dis- 
_ tinetly composed of an aggregation of very 
minute cells. Around the sides of the body 
muscular structure was also in the course of 
development, but as yet was exceedingly in- 
distinct, insomuch that Mr. Newport could 
discover no perfect fibre, a fact that sufficiently 
accounts for the entire absence of spontaneous 
_ Motion in the embryo up to this period. 
A new process was now about to commence 
—the development of new segments. On the 
third day, as has been already stated, the pos- 
terior part of the body is less distinctly divided 
into segments than the anterior, the first five 
Segments being most distinctly marked. The 
sixth and seventh are now more defined. It is 
in the membrane f, fig. 321, that connects the 
seventh with the eighth segment at the posterior 
‘Margin of which last the funis (d) enters, and 
which segment is permanent as the penultimate 
throughout the life of the animal, that the for- 
mation of new segments is taking pas At 
this period it is only a little ill-defined space 
that unites the seventh and eighth segments 
into one mass, but in proportion as the anterior 
parts of the body become developed, this part 
__ ts also enlarged, not as a single structure, but 
as a multiplication or repetition of separate si- 
“milar structures. 
On the ninth day the changes have advanced 
much further (fig. 320) ; 
‘not only have the future 
hew segments become 
‘more distinct, but trans- 
verse depressions are also 
Seen on the dorsal surface 
of the original segments, 
shewing their division into 
‘double ones, as in the 
“perfect animal. The rudi- 
ments of the legs are now 
further developed, and 
their transparent distal 
extremities are seen through the investing mem- 
brane applied closely together and extended 
along the ventral surface of the body, as in the 
MYRIAPODA. 
555 
nymphs or pupz of true Insects. The an- 
tenne and ocelli are more apparent, and the 
embryo itself has increased at least one-third 
of its original dimensions. It is still attached 
by the funis to the shell, but this attachment is 
daily becoming more fragile, and is now sepa- 
rated by very slight causes. The embryo has 
thus continued to grow through nine succeed- 
ing days, since the bursting of its shell, without 
any visible means of nourishment, the nutri- 
ment supplied by the yelk having been ex- 
hausted before that occurrence. Hence it be- 
comes a matter of inquiry from whence it now 
derives its means of growth? Whether it has 
already sufficient materials derived from the 
egg, and stored up within itself for its future 
development, or whether the external inclosing 
membrane may not still contribute to the func- 
tion of nutrition by absorbing fluid condensed 
from the air of the humid locality in which it re- 
sides. The probability of this last supposition, 
says Mr. Newport, is somewhat countenanced 
by the fact that I have constantly observed the 
membranes of the embryo at this period co- 
vered with microscopic drops of fluid, but 
whether this is fluid condensed on the mem- 
branes from the atmosphere of the dwelling, 
or whether it results from the transudation of 
that which was contained in the amnion, re- 
mains for future inquiry. 
Up to this period the embryo gives not the 
slightest evidence of spontaneous or voluntary 
motion. Internally it is still composed of cells 
of different sizes that are now in the course of 
producing muscular and other structures. In 
some parts of its body no arrangement of them 
seems as yet to have taken place, the cells 
being merely aggregated together. Cells of 
three very distinct sizes now exist. The dia- 
meter of the largest of these is nearly three 
times that of the second size, and the second 
again are nearly twice and a half the size of the 
smallest. The smallest sized cells fill up the 
interspaces between the others, and appear as 
if breaking down to form interstitial or cellular 
substance, while the second sized cells are 
arranged in rows to form particular structures. 
In the midst of these cells the alimentary 
canal is now nearly complete, but Mr. Newport 
was unable to observe its connexion with the 
funis. At its anal extremity it is a little dilated, 
and extends forward as a short straight intestine, 
the rectum, until it arrives at a part where a 
valve seems about to be formed. The diameter 
of the canal is there enlarged, and on its surface 
are three distinct longitudinal muscular bands. 
The so-called hepatic vessels also exist as dis- 
tinct tubes inserted one on each side into the 
alimentary canal at the constricted or valve-like 
part above noticed. The canal is then conti- 
nued forwards until it is again dilated into the 
proper stomach, and terminates or rather com- 
mences in a narrow cesophagus. It is much 
longer than the body of the embryo, being con- 
voluted or folded upon itself in its lower por- 
tion, to adapt it to the changes that the body 
undergoes in the enlargement and elongation 
of its segments. It is not yet separated from 
the now forming structures by any distinct 
