THE VICTORIAN NATURALIST. 149 



nearly straight, but in some families becomes looped. Connect- 

 ing the mouth with the stomach is a short oesophagus. 



There are two kinds of females — parthenogenetic, and the 

 ephippial, or sexually matured form. 



The ordinary or parthenogenetic female deposits a number of 

 ova in the brood-cavity on the dorsal surface, being held in 

 position by the large curved lappet on the dorsal surface of the 

 tail. 



When fully formed the young are thrown out at the posterior 

 edges of the valves. There is a close resemblance to the parent. 



Towards the summer males begin to appear, and now are 

 developed by the females what are known as the resting eggs. 

 These eggs require fertilization in order to develop. After 

 fertilization, the ephippium, with the enclosed eggs, is thrown 

 off, and, as the pond dries up, becomes embedded in the mud. 

 There the eggs will remain until the autumn rains fill the pond, 

 when the young will again appear, and so start another cycle of 

 generations. A few words about the male may be of interest. 

 In size they are inferior to the female. The shell is more 

 angular and much narrower. The superior antennae are larger, 

 and often attain a considerable length. The first pair of feet are 

 generally provided with a strong curved hook. Time of appear- 

 ance coincides with that of the ephippial female. 



SUB-ORDER— CLADOCERA. 



Family — DAPHNiDiE. 

 Genus — Uaphnia, Muller. 



Daphnia carinata, King, Proc. Roy. Soc. Van Diemen's Land, 

 vol. ii., part 2, p. 246, plate i., p. 253, plate vi.A ; G. O. 

 Sars, Arch. Natur, Christiania, xviii., No. 2, pp. 2-11 (includ- 

 ing typical form and varieties intermedia and magniceps). 



This fine species is very abundant in the vicinity of Melbourne, 

 occurring in almost every small pond, attaining a very large size 

 in pools of a clayey nature. In common with others of the genus, 

 variation occurs to a considerable degree, both in the shape of the 

 crest and length of spine. Fig. i closely resembles typical form 

 figured by Prof G. O. Sars. Fig. 2 shows a very distinct variety 

 from a pond in the Albert Park, the spine being extremely short. 

 This is very noticeable even in the very young. 



DistribiUion. — Near Sydney (King) ; near Hay ; near Sydney 

 (Sars) ; neighbourhood of Melbourne, Werribee. 



Genus — Simocephalus, Schoedeler. 



Daphnia elizabethce, King. 



Simocephalus elizabethce, King, G. O. Sars, Vid. Selsk, Christiania, 

 1888, No. 7, pp. 22-25, plate ii., figs. 6 and 7. 



