1885.] 



CLADOCERA. 



5 



serious impediment, possessing as I did an intimate knowledge of 

 all our indigenous species. The favourable results of this method 

 were soon apparent, the necessary aération of the water being 

 now effected, and thus any further development of Bacterians 

 at once obviated. 



But the difficulties attending my experiments were as 

 yet however far from siirmounted. Another quite unlooked 

 for and most perplexing obstacle had next to be encountered, 

 viz., the remarkably rapid increase of the Confervæ and other 

 fresh- water plants introduced into my aquaries, pushing, as they 

 did, their luxurious growth in all directions, and crowding up 

 the sides of the aquaries, so as very shortly, it would seem, to 

 choke up the water, and thus leave the aquaries wholly unfit to 

 serve as a habitat for any species of Entomostraca. As a means 

 of obviating this serious drawback, I placed in each of my 

 aquaries a few specimens of our indigenous fresh-water snails 

 (Limnæa), which soon were found eagerly to feed on the Con- 

 fervæ, thrived exceedingly well, and ere long began to propa- 

 gate, depositing their egg-cakes on the walls of the aquaries. 



Thus, after much trouble I at length succeeded in arriv- 

 ing at what I deemed relatively favourable conditions for the 

 breeding and subsequent development of Australian Cladocera, 

 the ova of which were contained in the mud; and notwith- 

 standing a great part of the ova had in all probability been 

 destroyed in the course of my experiments, yet the final result 

 must on the whole be regarded as comparatively successful, 

 since I am now enabled to lay before the Society descriptions 

 and figures of as many as 5 different species of Australian 

 Cladocera, all of which have been carefully examined from living 

 and full-grown specimens domesticated in my aquaries. More- 

 over, of Copepoda, a species of the genus Diaptomus, and of 

 Ostracoda, a species of Cypris, have been successfully hatched, 

 finally the forementioned fresh-water Bryozoan. The 3 last- 

 named forms I purpose describing in a subsequent Memoir; here, 

 I shall restrict myself to a detailed Report on the 5 species of 

 Australian Cladocera, raised from the mud. 



