10 G. C. Sars. 



large, fully as broad as the shell, and has the dorsal crest 

 strongly developed, its iuuer limit being well indicated by 

 the insertion of the anteunal muscles. The edge of the head 

 forms a quite even and uninterrupted curve from the cerv- 

 ical region to the tip of the rostrum. The specimens 

 examined were laden with numerous small eggs in the 

 matrix, and would accordingly seem to have belonged to 

 the earlier generations. In the structure of the fornix, tail 

 and various appendages, no differences could be detected 

 between this and the 2 preceding varieties. 



Observations. Some few specimens of the present 

 species were successfully hatched in my aquaria from the 

 mud received, but none of them arrived at full maturity, 

 apparently owing to the excessive increase in the same 

 aquaria of another form, a species of Moina. I am there- 

 fore not able to say into which variety these specimens 

 would have developed. The specimens, which had the 

 spine of the shell very much elongated and somewhat up- 

 wards curved, were watched for some time in the aquaria. 

 They kept themselves constantly near the bottom, moving 

 along it in the usual somewhat jumping manner. 



Occurrence. According to Mr. King, the present 

 species is rather common in the environs of Sydney. The 

 localities for the typical form ere not enumerated, whereas 

 for the 4 varieties he figures, none of which agrees with 

 thoes here described, the localities were recorded. Of the 

 typical form several well-preserved specimens were con- 

 tained in the sample first sent me for examination by 

 Prof. Ramsay. This sample was taken on the 13th August, 

 1888, from the "Waterloo swamps. The variety inter- 

 media was found in a sample taken by Mr. Lea from 

 some ponds «Near Hay». Finally, the variety magniceps 



