24 Or. O. Sars. 



numbers, and at last scarcely a single male specimen was to 

 be detected, though the females were still present in great 

 numbers, multiplying in the usual parthenogenetical manner. 

 In some of my aquaria, a 2nd bisexual period was observed, 

 and thereby the «polycyclar» character of this form ascer- 

 tained. 



In habits, this form agrees with the other species of 

 the genus. The movements of the animal are rather rapid, 

 and effected by short abrupt jerks, whereby the body gener- 

 ally assumes a somewhat prone attitude. The males, as 

 usual, are still more agile, and were often seen eagerly to 

 pursue the females. I also happened several times to 

 observe the male getting a rather firm hold of the female? 

 embracing with his powerful antennulæ the lower part of 

 her shell, and at the same lime inserting his prehensile 1st 

 pair of legs within the edges of her valves. 



Occurrence, — The mud, from which this species was 

 raised, was taken by Mr. Whitelegge from waterholes at 

 Bourke Street, opposite Lachlan Street, and off Botany Road, 

 near Waterworks Bridge. A spirit sample taken from 

 the same localities likewise contained numerous specimens 

 of the same species. Moreover, the greater number of the 

 specimens contained in the sample first received from 

 Prof. Ramsay, and taken from the Waterloo Swamps, turned 

 out, on a closer examination, to belong to the said species. 



8. Moina tenuicornis, G. O. Sars, n sp. 

 (PI. 4.) 

 Specific Characters. — Very like the preceding spe- 

 cies, but differing rather markedly in the shape of the head ; 

 which does not exhibit any trace of a sinus above the eye, 

 and moreover in the female, forms below, at the insertion 



