40 



G. 0. SABS. 



[No. 7. 



Of course I was at that time eagerly searching for male speci- 

 mens, and at last succeeded in detecting a few very small 

 specimens, the fully developed sexual organs showing them to 

 be adult males, one of which is figured on the accompanying plate, 

 fig. 5. In one of the aquaries I allowed the water to evaporate 

 and kept the bottom-residue in a dried state until the following 

 summer, 1887, when fresh water was again poured on it; and 

 in the course of that season I had the satisfaction of seing nu- 

 merous examples of the present species reappearing, which had 

 evidently been hatched from winter-eggs deposited in the mud 

 the preceding year. Moreover, I prepared the same summer a 

 small aquary with a parcel of mud from the same locality, kept 

 during the winter in its original dried state; and also in this 

 aquary the same form was hatched and successfully domesticated 

 in the course of the following months. 



In its habits the present form closely resembles the other 

 known species of the genus. Like the latter, it is a true limi- 

 cole form, spending most of its time at the bottom more or less 

 deeply immerged in the loose mud, through which it slowly drags 

 itself by the aid of its antenna? and powerful tail, generally 

 with the belly turned upwards. It is, however, by no means 

 quite devoid of swimming power, as are the other known species 

 of the genus. In fact I have not rarely seen the animal leaving 

 the bottom and moving about freely through the water, though 

 certainly in a very slow and laborious manner, by rapidly re- 

 peated strokes of its antennae. The cause of this clumsy swim- 

 ming motion is evidently the absolute want of cilia on the 

 natatory setae, the antennas themselves being very powerfully 

 developed, but more properly adapted for the usual dragging 

 motion on the bottom. 



Occurrence. — The mud from which the greater part of the 

 specimens developed, was collected on the 28th August 1885, 

 from the Gracemere Lagoon, the same locality that yielded the 

 several species of Cladocera described by the author in a pre- 

 vious paper. As mentioned above, I also succeeded in raising 

 this form from another parcel of mud, viz., that from which the 



