ZOOLOaY AND BOTANY, MICEOSCOPY, ETC. 71 



least in many cases) the separation of the arms of many Asterida is 

 connected with the evacuation of the sexual products. 



Coelenterata. 



Local Colour- varieties of Scyphomedusae.* — R. v. Lendenfeld 

 points out that Crambessa mosaica in Sydney is brown, whilst in Mel- 

 bourne it is deep blue. The brown colour is due to cells of parasitic 

 Algse — Zooxanthella, of which the Melbourne specimens never show 

 any trace. In the cold water of Port Phillip it appears not to be 

 advantageous for the Medusae or the Algfe to live in symbiosis, whilst 

 it would seem to be so in the warm water of Port Jackson. The author 

 calls the Melbourne variety Crambessa mosaica conservativa, and the 

 Sydney variety Crambessa mosaica symbiotica. He considers the 

 difference between the two to be evidently the same as that between 

 fungi and lichens, and should the variety symbiotica adajjt itself so 

 wholly to this symbiosis as not to be able to live without the 

 Zooxanthella a new species will have been formed, which, as it has not 

 been mentioned by any previous observer, may have been produced 

 within the last forty years. 



Gyanea annashala E. v. L. occurring in the same localities differs 

 in colour and in size in the two places. 



The Melbourne specimens never grow beyond 10 cm. in diameter, 

 and possess mouth-arms which are deep purple throughout ; whilst 

 those from Sydney are 20 cm., and the purple colour in the mouth- 

 arms is found only at the margin. The author, therefore, dis- 

 tinguishes provisionally two varieties of this species — Cyanea 

 annasTcala purpurea and C. annashala marginata. 



These variations he considers to be due to difference in tempera- 

 ture of the water. 



Scyphomedusse of the Southern Hemisphere.f — R. v. Len- 

 denfeld gives descriptions of all known ScyphomedusEe from the 

 southern hemisphere, adopting Hackel's classification. Of the 210 

 known species, 104 have already been found in the southern hemi- 

 sphere. Only 26 of the 104 southern species are Australian, but 

 this apparent poverty of the Medusae is due to the limited investiga- 

 tions that have hitherto been made. 



In a further paper on " The Geographical Distribution of the 

 Australian Scyphomedusae," | the distribution at all events of the large 

 Ehizostomes, is shown to be entirely controlled by the ocean currents. 



Pseudorhiza haeckelii.§ — W. Haacke looks upon this new species, 

 which he found in the Gulf of St. Vincent, South Australia, as the 

 terminal bud of the stem of the Discomedusse. It belongs to the 

 same genus as the P. aurosa, lately described by von Lendenfeld, 

 but as to the exact systematic position of which that naturalist was 

 in some doubt. It is particularly remarkable for the fact that the 



* Ann. and Mag. Nat. Hist, xiv. (188i) pp. 409-12. 



t Proc. Linn. Soc. N. S. Wales, is. (1884) pp. 155-69, 242-9, 259-306 (2 pis.). 



X Ibid., pp. 421-33. 



§ Biol. Centralbl., iv. (1884) pp. 291-4. 



