24 G. 0. SAES. [No. 7. 



the posterior edge of the valves, as in S. serrulahts. The ven- 

 tral edges are strongly inflexed and fringed, as in the other 

 species of the genus, with delicate bristles, scarcely however 

 projecting beyond the carapace. 



The eye agrees both as to size and position exactly with 

 that in the preceding species. 



The ocellus, on the other hand, is highly distinguished by 

 its anomalous form, having the appearance of a narrow, elongate 

 black stripe, pointing obliquely downwards to the rostral pro- 

 jection. As regards this organ, the present species agrees how- 

 ever exactly with the European form S. vetuhts (Muller). 



The antennulae and the antennae, as also the oral parts and 

 the legs do not exhibit any essential differences from those parts 

 in the preceding species. 



The tail (fig 7), though on the whole exhibiting a structure 

 similar to that in the last species, differs in being comparatively 

 less expanded and in having the supraanal angle considerably 

 more projecting and fiuely denticulate. Moreover, the caudal 

 claws wholly want the comblike row of secondary denticles pre- 

 sent in the preceding species at their base; and the anal den- 

 ticles are fewer in number, not exceeding 6 or 7, the superior 

 ones being very small. 



The colour is pale chestnut or somewhat resembling that in 

 the preceding species, and the valves exhibit likewise some few 

 irregularly scattered patches of a bright yellow tint. 



Biological Observations. — The above-described species I 

 first noticed on the 19th June 1886, in a very small aquary, 

 prepared on the 13th of the same month. It was then still rather 

 small, but rapidly increased in size during the following 

 days, and soon became loaden with eggs. In the same aquary 

 were hatched several specimens of Moina iwopinqva, described 

 by the author in a previous paper, and, as usual, this form ra- 

 pidly multiplied, till the aquary at last actually swarmed with 

 the young brood. This having previously proved fatal to the 

 development of other Entomostraca, I thought it better at once to 

 secure the specimen, which accordingly was fished up on the 



