12 



G. 0. SARS. 



[No. 8. 



the head forward. It still, however, continues enveloped in a 

 thin embryonal cuticle, within which not only lie all the bristles 

 of the limbs, but also the large frontal process, so characteristic 

 of the present species, this process being folded back along the 

 ventral margin of the head, thus giving the frontal part in this 

 stage (see Pl. 1, fig. 9; Pl. 4, fig. 1) an evenly rounded contour, 

 as in the ordinary species of Daphnia. Moreover, the large spine, 

 jutting forth posteriorly from the carapace, lies at first folded 

 up along the ventral face of the body, the latter exhibiting, too, 

 a well-marked embryonal curvature. Very so on, however, after 

 birth this embryonal cuticle is east off; the body then exserts 

 itself, and the young Daphnia at once appears (see Pl. 1, fig. 

 10), with the habitus so characteristic of the present species, 

 moving quickly about in the water by the aid of its natatory 

 antennæ. 



