On Fresh-water Entomostraca. 65 



distinctly traced through the shell, both in its lateral and 

 dorsal views, appearing as 2 large, juxtaposed bags extend- 

 ing through the posterior half of the shell, and exhibiting 

 within from 5 to 6 verticils of bristle-like radiating pro- 

 cesses. Also the spermatic tubes contained within the 2 

 lamellæ of the valves may be fairly well discerned. 



Observations. — An adult male specimen of this form, 

 the one here figured, was by a mere chance found in one 

 of my aquaria, on taking up, by the aid of a dipping tube, 

 a small quantity of the bottom deposit. It was at once sub- 

 jected to a closer examination under the microscope, and 

 its habits studied. Though subsequently very closely exa- 

 mining the bottom contents of this aquarium, I did not 

 succeed in detecting any more specimens. In habits, this 

 form agrees with the typical species, as also with the species 

 of the genus Ityodromus, as it moves rather quickly through 

 the loose bottom deposit, but is wholly devoid of swimming 

 power. 



Occurrence. — The mud, from which this form deve- 

 loped, was taken by Mr. Whitelegge from waterholes at 

 Bourke Street. . Numerous specimens of the same form, 

 both males and females, moreover, occurred in a sample 

 taken by that gentleman from the Marubra Swamp. The 

 specimens examined by Prof. Brady were derived from 

 Condong, Tweed River, New South Wales. 



