4 G. 0. Sårs. 



about these early developmental stages. It was, not however, 

 until many years afterwards that I had the opportunity of 

 renewing my observations upon this subject. Of late 

 years I have, as a rule, spent some part of every summer 

 at the Biological (Station at Drøbak, and here, by a 

 suitable catching method, I have succeeded in finding 

 Euphausiid-eggs in great abundance. It has thus been pos- 

 sible for me to institute a closer examination both of fresh 

 and preserved material, and, though some difficult ques- 

 tions still remain to be solved, I have thought it right 

 now to publish the results of my investigations, hoping 

 subsequently to give some supplementary remarks upon the 

 subject. 



Although the chief aim of the present paper is to 

 give an abbreviated account of the embryonal development, 

 which as yet is very imperfectly known, I have found it 

 advisable in connection therewith to describe and figure also 

 the earliest stages of the larval development, because these 

 stages have only quite accidentally been observed by other 

 authors, and their mutual relation has accordingly not yet 

 been satisfactorily recognized. On a closer examination of 

 the so-called ova, both in a fresh and a preserved state, I 

 have observed some highly remarkable structural features, 

 which have induced me to put forward some very perplexing 

 suggestions about the nature of these bodies. Indeed, I 

 have found that they are of 2 very different kinds, as indi- 

 cated by the terms here proposed oosphères and spermato- 

 spheres, both, however, exhibiting the very same outward 

 appearance. If my suggestion about the nature of these 

 bodies be correct, it will lead to an equally perplexing sup- 

 position as regards the propagation of these interesting 

 Crustacea. 



