1864. | Durturers on the Formation of Coral. 623 
remain there, undergoing transformation up to the moment of the birth 
ofthe embryo. The spermatozoa becoming free by the rupture of the 
capsule which enclosed them are ejected, and fertilize the ova of the 
females, either directly, if these be near at hand, or by comparative 
accident if they are not in immediate proximity to the male polype. 
The emission of the spermatic fluid of the male can be easily detected 
by direct observation, for it is only necessary to examine some of the 
living coral at the moment of reproduction, to see the polypes throw 
out jets of a white liquid, which forms a cloud in the water, and in 
which, also, the characteristic male elements or the spermatozoa will 
be discernible. 
The ovum, as we have just seen, after detaching itself from the 
intestiniform folds, falls into the general cavity, where it is fertilized 
and undergoes its first changes; but in this same cavity another im- 
portant junction is also accomplished, namely, that of digestion. The 
same organ therefore serves both as a stomach and a matrix, or more 
properly speaking as an ovisac, and in it two substances, under condi- 
tions which appear to be similar, can nevertheless undergo modifica- 
tions thoroughly opposed to each other; for the one is dissolved and 
liquified, while the other increases in bulk, and produces a new being. 
This physiological peculiarity cannot fail, from its strangeness, to 
attract attention; it shows what an immense difference exists between 
the higher and lower animals, and how difficult it is to judge @ prior? 
of the one by the other. 
As a summary, it may be said that coral follows the ordinary laws 
of reproduction, and does not present the variations which are met with 
among some of the inferior animals. For a very short period after its 
birth it enjoys the power of movement, but as soon as it begins to 
undergo its metamorphoses the ability to move is lost, and the animal 
fixes itself in one place, which it does not afterwards desert. Then, 
too, its early form is lost, and it is no longer possible to recognize in 
its branches, so elegant in form and so rich in colour, the little white © 
worm from which these were developed. All these facts have, without 
doubt, a special importance in the history of coral; but they show, 
also, how the study of the inferior organisms reveals each day some 
new and unexpected facts; how little the phenomena of life through- 
out the animal series are as yet understood; and they teach us that 
such investigations should be conducted with extreme care, and 
that due reserve and caution should be exercised in reasoning from 
analogy, and in the application of what we regard as universal laws. 
ho 
cq 
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