CORALLINES. 
135 
much more numerous in the red than in the light band, and they 
uecessarily give more strength to the general tint. 
To the mode of reproduction in the coral polypes, so well described 
by Lacaze-Duthiers, we can only devote a few lines. Sometimes, ac- 
cording to this able observer, the polypes of the same colony are all 
either male or female, and the branch is unisexual ; in others there 
are both male and female, when the branch is bisexual. Finally, but 
T ery rarely, polypes are found uniting both sexes. 
The polype is viviparous ; that is to say, its eggs become embryos 
inside the polypes. The larvae remain a certain time in the general 
is not equally distributed, but separated into zones more or less 
deep in colour, containing very thin preparations which crack, not 
irregularly, but parallel to the edge of the plate, and in such a manner 
as to reproduce the festoons on the circumference. From this it may 
bo deduced that the stem increases by concentric layers being de- 
posited, which mould themselves one upon the other. In the mass ot 
coral certain small corpuscles occur, charged with irregular asperities, 
much redder than the tissue into which they are plunged. These are 
Fig. 54. Birth of the Coralline Larvae. (Lacaze-Duthiers.) 
