88 ME. GEOFFREY "WATKIN SMITH ON THE 



The uropods are long, equalling in length the first abdominal segment. They are 

 furnished each with four terminal plumose setae and one lateral ; these setae are not 

 quite half as long again as the uropods. 



The first antennae are long, equalling the length of the body ; they consist of 27 joints. 



The second antennae are similar in structure to those of Boeckella, and so are the 

 mandibular palps ; the biting-edge of the mandible has the form shown in PI. 18. fig. 8. 



The maxilla (PI. 18. fig. 9) resembles that of Boeckella very closely, but has rather 

 fewer setae. The same applies to the first maxillipede (PI. 18. fig. 10). 



The second maxillipede (PI. 18. fig. 11) closely resembles that of Boeckella, but the 

 internal lobe on the first joint is more prominent. 



The first thoracic limb (PL 18. fig. 12) has the external ramus 2-jointed and the 

 internal ramus 1-jointed. 



The third limb (which resembles closely the second and fourth) has the form shown 

 in PI. 18. fig. 13. The external ramus is 3-jointed; the internal is 2-jointed. The 

 arrangement of the spines and setae is always constant as in the figure. 



The fifth leg of the female (PI. 18. fig. 14) has the external ramus 3-jointed and the 

 internal 2-jointed. The stout spine on the penultimate joint of the external ramus is 

 not plumose. 



Length 7 mm. 



Colour. Green. 



Occurrence. In great numbers in a weedy freshwater lagoon near Adventure Bay, 

 Bruni Island. 



Male. — The male differs from the female in having the first antenna normally 

 geniculated (PI. 18. fig. 8) and in having five distinct segments in the abdomen. 



The last pair of legs are very peculiar. 



The right leg (PI. 18. fig. 16) has the external ramus 2-jointed ; the joints are flattened 

 and expanded, and there is a short stout spine on the terminal joint. Otherwise setae 

 are absent. The internal ramus is 2-jointed, the terminal joint bearing four long setae. 

 The other joint has a peculiar lobe upon it, and also another internal lobe springs from 

 its base. 



The left leg (PI. 18. fig. 15) has the external ramus 3-jointed, if we count the terminal 

 claw as a joint. There is a small spine at the top of the first joint and another small 

 spine on the base of the claw. The internal ramus is 3-jointed, the terminal joint 

 carrying four setae. 



Family Ctclopidj). 



Genus Cyclops, O. F. Midler. 



Besides one species, C. amtralis, King, characterised by Sars as peculiar to Australia 

 (Archiv for Math, og Naturvid. xviii.), the latter author reports (loc. cit.) several common 

 European species from small pools in and around Sydney (e. g., G. albldus, C. serrulatus, 

 C. ajrjinis, &c). This occurrence of species identical with those found in Europe is a little 

 suspicious, as nothing of the sort occurs among the other groups of Entomostraca, 

 almost all the species of Cladocera being peculiar. The species found in Tasmania, 

 although very closely related to European forms, are distinguishable as separate species. 



