William Lundbeck: Some remarks on the7eggs and egg-deposition of Halobates. 11 



pletely surrounded by the mass (PI. I, fig. 6). In one specimen (No. 20) the glue-like 

 mass is especially abundant, and the eggs are wholly imbedded in it. For the rest 

 the eggs are laid without any apparent order, or at most a few are found beside 

 each other more or less parallel as shown in PI. I, fig. 1 — 3. The single eggs are, on 

 the other hånd, always fastened in a certain manner, always sitting with the flat 

 dorsal side downwards, towards the substratum, and the more arched ventral side 

 turning upwards. When several eggs are found side by side they all point with their 

 head-ends in the same direction ; the apparent want of order of the eggs is, probably, 

 also for a great part due to several females having laid their eggs together, and most 

 likely after each other. In several of the specimens also groups of about twenty odd 

 eggs are to be seen, all with their front ends in the same direction ; such a group 

 is no doubt laid by one female, and some order may then be traced of rows fol- 

 lowing each other, each consisting of a few eggs ran ged parallel side by side. The 

 shape of the substratum, for the rest, certainly to some degree influences the 

 deposition, and in the few specimens which show so small a number of eggs, that 

 these may possibly originate from one single female, and where therefore the eggs 

 might be expected to show some order, the underlayer is just of so small an extent 

 that it has not been possible to place the eggs on one surface, but they are placed 

 over the whole object, whereby the order is effaced. When the underlayer gets 

 strongly covered with eggs so that they lie in layers above each other, every order 

 disappears. 



As mentioned above Fairmaire found 15 — 20 eggs in one female, and Buchnan 

 White about 25. The number one female lays must therefore be supposed to be 

 near those numbers. Most of the specimens before me show a great or very great 

 number of eggs, and must therefore originate from several or many females ; only 

 one specimen, No. 9, shows comparatively few, about 30 eggs, which thus may pos- 

 sibly proceed from one female, and of three other specimens, each with about 50 

 eggs, the same may perhaps be the case. That as a rule several or many females 

 deposit their eggs together evidently is in accordance with the faet that the Halobates- 

 species are gregarious, and it ought to be remarked, that when the objects on which 

 the eggs are laid have some extent, the eggs always are found more or less numer- 

 ous. Eggs which according to their number might possibly be laid by one female 

 are only found on very small objects. No. 5 is the specimen which contains the 

 greatest niunber of eggs, many thousands lying in many layers above each other 

 (PI. I, fig. 4) ; here a great swarm of females must have laid their eggs together, and 

 it looks as if they were laid in a comparatively short time, as there are no embryos 

 in any of the eggs. In other cases the degree of development of the eggs shows 



