William Lundbeck: Some remarks on the eggs and egg-deposition of Halobates. 9 



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 specilically 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. 



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 Q^g, 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 stronglv ^. ^ -r. . j ,. , ,i /,. ^t r; 



^ '' Fig. 3. Front end of an egg-shell (from No. 5) 



marked or disappearing. The shell may, y showing the micropyle x 200. 



as mentioned above, be somewhat dif- 

 ferent 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 piaces 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; 



