1888.] AUSTRALIAN CLADOCEKA. 21 



on the 10th of that month. The specimen was in a rather ad- 

 vanced stage of development and already provided with large 

 greenish ovaries. On the 25th, the ovaries had discharged their 

 contents into the incubatory cavity, now filled with numerous 

 dark greenish globular ova. Before the close of the month the 

 young brood had escaped from the mother, and very soon the 

 latter was again loaded with eggs. It was now fished up, by 

 the aid of the dipping tube, and submitted to a closer examina- 

 tion under the microscope, an accurate coloured drawing being 

 made from the living animal (fig. 1). The young of the 2nd 

 generation rapidly increased in size, and as early as the 4th 

 July some of them had already a few ova in their incubatory 

 cavities. This brood did not. however, by far attain the size of 

 the specimen first observed and they were also considerably 

 paler in colour and much less prolific. It was evident that the 

 conditions of life in the aquary had turned out less favourable 

 to their further growth. For in the course of a few days they 

 diminished considerably in number, and the remaining specimens 

 had^a rather morbid appearance, some of them showing an evi- 

 dent intimation to the formation of ephippium. But no true 

 winter-ova were produced, nor could any male specimen be found 

 and by the middle of the month not a trace of their existence 

 remained. 



The habits of the animal, as observed in the aquary, were 

 very similar to those of our native species. It is not very active, 

 remaining for some time together affixed dorsally, on the same 

 spot, either to the walls of the aquary or to some aquatic plant, 

 the chief affixing organs being apparently the above described 

 hooked setae on the antennae. Only now and again does it make 

 a short run through the water, this natatory motion being in 

 no case continued for any length of time. It always swims on 

 its back, moving about with uniform speed by rapidly repeated 

 strokes of the antennae; but very soon it again clings to some 

 submerged object, so as generally but with great difficulty to 

 be observed. 



Occurrence. — The mud from which I raised this species, 



