136 
DE. E. YON WILLEMOES-SUHM ON THE 
end of the lateral horns. These are in the young embryo not yet erected, but still 
hanging down. On the extremities of the appendages, however, I observed nothing of 
the kind. They are three in number (fig. 11, a, b , c), and indicate already all the 
peculiarities which will be described in the full-grown Nauplius, and which in this 
stage can best be understood from the figure. The upper lip (fig. 11, la) is already 
plainly visible ; and, apparently, also the oesophagus, on both sides of which we find a 
group of cells in the place where we afterwards see two glands, which perhaps lead 
into the stomach. The intestine shines through the body of the larva, in which there 
are as yet a great many yelk-granules, which prevent you from seeing the intestines, 
upper and lower portion. 
The first change is undergone by the Nauplius very soon after it has left the ovum. 
In a globe into which I had put a ball of barnacles, and in which at first all the larvae 
were in the stage just described, I had some difficulty in finding any of them half an hour 
afterwards, as the greater number had already cast off the cuticle, pushed their tails 
and spirals out, and erected their horns. I have been thinking whether this cuticle is 
not perhaps the blastoderm adhering to the embryo, which leaves it very much as a 
Botriocephalus embryo leaves its ciliated larval skin. For reasons which I have given 
when describing the development within the ovum, I am, however, not quite sure 
about this, and shall only be able to decide the question when I have studied other 
Lepadidee which may be caught on the surface during the progress of our voyage. 
In the first Nauplius stage I saw a lens above the eye (fig. 11), which I did not, 
however, see in every, case when I looked for it, and which in the later stages was seen 
no more. 
After the first moulting the embryo has grown very much, having already a length 
of 0-6 millim., but showing only few differences in its organization, as all the spines 
on the tail, and especially the first two movable ones (Plate 11. fig. 13, sp ), existed 
previously. At the end of the lateral horns we do not yet find those fine hairs which 
distinguish the later stages, but only a few small setae and a larger one (fig. 13, cp). 
Muscles are seen running up to the horns ; but the glandular system which is beginning 
to form inside the body, indicated by small granulated cells, is not yet in connexion with 
them. In the upper lip, the sides of which are covered with fine hairs, indications of the 
teeth may be seen ; but as yet the whole of the intestinal tract shows no progress, except 
that the anus is now clearly visible. On both sides of the eye we find two tentacles, 
well-known sense-organs the function of which is very doubtful and likely to remain so. 
The carapace shows as yet no protuberances, with the exception of the lateral horns 
and two small spines at the base (fig. 13, z). In the appendages the setse are very much 
larger, especially the one which springs from the segmented ramus of the third pair, 
which is as long as the tail itself. After the larva; had reached this stage in our globes 
they invariably died, which has also very likely been the case with those of former 
observers, as nobody seems to have ever seen the very interesting ( Archizoea ) stages’ 
which I am now going to describe, and which were found on the surface with the 
