IQ G. 0. Sårs. 



that in the far greater number of Euphausiidæ the ova are 

 at once ejected into the water. Indeed, the observations 

 given in this paper prove without doubt that the whole 

 embryonal development, from the very first cleavage, is 

 going on in the free ova. 



In some cases spermatophores are found attached to 

 the ventral face of the female in the place where the genital 

 openings are believed to occur, and this seems, indeed, to 

 prove, that in such cases the ova must be fecundated before 

 being ejected from the oviducts. Moreover, the peculiar 

 transformation in male Euphausiidæ of the inner rami of 

 the 2 anterior pairs of pleopoda, sometimes also of the 

 peduncle of the superior antennæ (Boreophausia inermis), 

 seems to indicate, that these appendages must in some man- 

 ner be subservient to copulation. Notwithstanding this, I 

 am led by the observations here given to believe, that in 

 some cases at least, perhaps even more generally, the fecun- 

 dation of the ova may be effected after they are ejected 

 by the peculiar egg-like bodies described below as sperma- 

 tospheres. The possibility of such a mode of fecundation 

 may be explained by the gregarious occurrence of the Eu- 

 phausiidæ. It is here worthy of note, that in those places at 

 Drøbak where the ova occurred in great abundance, not a 

 single adult Euphausiid was ever found, which fact seems to 

 prove, that the ova must have been brought by the current 

 from some place in the outer part of the Fjord, and may 

 consequently be assumed to have been suspended in the 

 water for some time, and yet ova were found in the 

 very first stages of cleavage, and occasionally even some 

 in which cleavage had not as yet commenced. Now it 

 is well known that the first cleavage takes place very 

 soon after fecundation, and it must accordingly be as- 



