PRESIDENTIAL ADDRESS. 31 



bare and desolate, migrant shoals of fish avoided the place, 

 those that had lived amid the forest of brown kelp, dis- 

 appeared, and molluscs including the valuable Haliotis also 

 vanished. 



The explanation of this phenomenon supplied by Yendo 1 

 is that the fresh water pouring out of a river in heavy flood 

 was turned aside by the coastal current and projected on 

 to the affected area. When thus immersed in fresh water, 

 the marine algse at once died, and their loss carried destruc- 

 tion to their associates. 



After storms of wind and rain, I have noticed numbers 

 of the razor-shell Solen solanii and the gephyrean Dendro- 

 stoma dehamata thrown up on a beach in Middle Harbour 

 in a moribund condition. 2 A gale without rain does not 

 dislodge these, so their destruction is probably caused by 

 poison of tannin or other deleterious matter from decayed 

 plants. 



Transition from Marine to Terrestrial. 



It is agreed that all terrestrial organisms had a marine 

 origin. The beach is at last the font of all life whether 

 aerial, fluviatile, terrestrial, pelagic or abyssal. In the 

 higher animals, vestigal features demonstrate that respir- 

 ation was aqueous before it was aerial. 



Dr. A. B. Macallum 3 considers that the difference in 

 chemical composition between blood and salt water is slight, 

 and that the Paleozoic Sea being poorer in magnesium, 

 was still more like blood than is the existing sea water. 

 He concludes that a circulatory system, once open to the 

 sea, of a marine vertebrate ancestor became closed, and 

 that the animal, then migrating ashore, carried with it a 



1 Yendo, Econ. Proc. Eoy. Dubl. Soc. ii, 1914, pp. 105 - 122. 



2 Hedley, Proc. Linn. Soc. N.S. Wales, xxv, 1899, p. 432; and Kesteven, 

 Eec. Aust. Mus., v, 1903, p. 69. 



3 Macallum, Trans. Canad. Inst,, vii, 1904, p. 535. 



