TRANSACTIONS OF SECTION D. 709 



forms ; they need explanation in terms of the structural, and yet more of the 

 functional, properties of protoplasm itself. Were this once done, it would actually 

 be possible to retrace the progress of the science, and in the same way interpret, 

 in terms of the functions of protoplasm, the forms and functions of tissues and 

 organs — nay, even the facts of aspect, habit, and temperament themselves — thus 

 reaching the rationale of what, had hitherto been matter of empirical observation 

 only. 



The functions of protoplasm are essentially two : first that of constructive or 

 synthetic change or metabolism (assimilation or anahoLisni), contrasted with that 

 of destructive or analytic change (disassimilation or hatabulisni), and these two 

 sets of changes never absolutely balance, as all the phenomena of rest and motion, 

 growth and diminution, nutrition and reproduction clearly show. During life 

 neither process can completely stop, but their algebraic sum varies within wide 

 limits. Starting from the undifferentiated amoeboid cell, a surplus of anabolism 

 over katabolism involves not only a growth in size, but a gain in potential energy, 

 and a reduction of kinetic, i.e., a diminution of movement. Irregularities thus 

 tend to disappear ; surface-tension, too, may aid ; and the cell acquires a spheroidal 

 form. Again, starting from the amoeboid cell, if the katabolic tendency be in 

 excess, the increasing liberation of kinetic energy thus implied must be expressed 

 in increased activity with diminished size. The form of the ovum and spermatozoon 

 are thus explained as the outcome of protoplasmic activities of a respectively pre- 

 ponderating constructive and destructive kind. 



This conception of sex at once leads to the hoped-for abundance of interpre- 

 tation ; thus the gradual differentiation of the two sexes becomes intelligible, since 

 necessitated by the accumulation of one or other of these two great tendencies with 

 advancing age, and (passing over the endless application of the theory to such 

 problems as those of the alternation of generations, hermaphroditism, partheno- 

 genesis, &c.), it affords us an explanation of the differences and habits, and even of 

 the determination of the sexes in plants and animals. Thus the degenerate male 

 rotifer is no mere exceptional curiosity, but the extreme development of a tendency 

 visible everywhere, for (save among those higher animals where the strain of 

 reproduction on the female necessitates the doubled activity of the male), females 

 tend on the average to show better growth or larger size. In plants or tadpoles 

 alike the determination of sex has been shown to be effected hy nutrition, and to 

 be female when this is abundant, male when it is checked. The phenomena of 

 sex, then, are no isolated ones, but express the highest outcome of the whole 

 activities of the organism- — the literal blossoming of the individual life. 



The preceding argument will also be found somewhat more fully in the writer's 

 article on Sex in the ' Encyclopredia Britannica,' and in extended form in a paper 

 of similar title to the present in tlie ' Proceedings of the Roval Society of Edin- 

 burgh,' 1886. 



2. Notes on Australian Coelenterates. By Dr. R. VoN Lendenfeld. 



The author describes the extraordinary mode of development of Phyllorhiza 

 punctata, a rhizostomous Medusa discovered by him in Port Jackson. The Ephyra 

 has eight, the next stage twenty-four, the next sixteen, and the adult again eight 

 marginal bodies. If the umbrella margin is injured and newly formed, marginal 

 bodies appear between all the newly formed flaps. 



Further, the migrations of Crambessa mosaica at the breeding time are described. 

 This and other species of that genus of rhizostomous MedusEe migrate far up the 

 rivers, like the salmon, to deposit their young. 



A remarkable change in the colour of Crambessa mosaica which has taken 

 place in Port Jackson since the observations of Huxley about forty years ago, is 

 described. A new variety, which is brown, seems to have been produced or to have 

 immigrated and superseded the blue form, which was observed by Huxley and 

 others in that locality. In Port Phillip the blue variety is still exclusively found. 



The author has found, in examining the lower freshwater animals, that the 

 freshwater Ilydroids and Sponges, as also the freshwater Rhizopoda of Australia, 



