Mindeskrift i anledning af hundredaaret for Japetus Steenstrups fødsel / XXVII. Some Remarks on the Eggs and Egg-deposition of Halobates / 9 (1914) Author: Hector Jungersen, Eugen Warming Table of Contents / Innehåll | << Previous | Next >>
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breadth 0,4 mm. The locality for these eggs is in the same parts as for the last
mentioned. — Finally we have from No. 19, Torres Street a small piece of sea-weed
with eggs, which show a sculpture almost as in the eggs from No. 13, 16 and 17,
and which perhaps is not specifically different from them; the shell is thick, but the
spines or emergences are fine and more distant; the length is 1,1 mm and the breadth
0,4 mm; Halobates sericeus Esch. and regalis Carp. are taken near to that locality.

Fig. 3. Front end of an egg-shell (from No. 5) showing the micropyle x 200.

The eggs of Halobates are comparatively large; the length is from a little below
1 mm to 1,2 mm, which is a considerable size, as the imagines do not reach a greater
length than 5,5 mm. The eggs are of a longish oval shape, sometimes a little more
elongated, and then almost cylindric with rounded ends. The dorsal side of the
egg is flat or only slightly arched, the ventral side somewhat more arched. Also the
two ends are different, the head end being somewhat broader than the posterior. It
is thus in general not difficult to orientate the egg only after its shape. The shell,
the so-called chorion, is solid, but varies
somewhat in thickness in the different
species; when it is thicker it always
seems to be thickest on the ventral side
and at the anterior end; when the shell
is thin this difference is less strongly
marked or disappearing. The shell may,
as mentioned above, be somewhat
different in the different species as to sculpture. It is sometimes simple and plain, and
it can have a stronger or slighter sculpture; in the simplest cases the surface then is
very finely spined with short, close standing, spine-like, more or less fused projections,
which at some places pass into a fine crenulation; or the shell is all over more or
less slightly crenulated, likewise with the low emergences somewhat fused together;
further it can also be more strongly spined with relatively short, close standing,
generally blunt spines or emergences, which are more or less fused into sinuous crests.
Finally it can show a more strongly marked sculpture, with isolated thickenings, the
margins of which run into prominent elongations, as described above. In all the
cases where a sculpture is present, the same is strongest on the ventral side and at
the anterior end, and it decreases evenly towards the dorsal side, where it tends
to disappear, or the shell is here quite smooth. The eggs sculptured have always
a comparatively thick shell, and it is, as mentioned, thickest on the ventral side.

There is only one micropyle, which has its place in the front pole of the egg,
or at any rate very near to it. The shape of the micropyle is rather characteristic
(Fig. 3); it begins on the surface of the shell as a very low, funnel-shaped deepening;

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