The circulation of alimentary fluids in the coral is accomplished by means of vessels near to the axis, without, however, directly anastomosing with the cavities containing the polyps which live in the polypidom; they only communicate with those cavities by very delicate intermediary canals. The alimentary fluids they receive from the secondary system of network, which brings them into direct communication with the polyps. The alimentary fluids elaborated by the polyps pass into the branches of the secondary and irregular network system, in order to reach the great parallel tubes which extend from one extremity of the organism to the other, serving the same purpose to the whole community. When the extremity of a branch of living coral is torn or broken, a white liquid immediately flows from the wound, which mingles with water, and presents all the appearance of milk. This is the fluid aliment which has escaped from the vessel containing it, charged with the débris of the organism. What occurs when the bud produces new polyps? It is only round well-developed animals, and particularly those with branching extremities, in which this phenomenon is produced. The new beings resemble little white points pierced with a central orifice. Aided by the microscope, we discover that this white point is starred with radiating white lines, the edge of the orifice bearing eight distinctly-traced indentations. All these organs are enlarged step by step until the young animal has attained the shrub-like or branched aspect which belongs to the compound polypidom. The tube is branching, and the orifices from which the polypi expand become dilated into cup-like cells. [Illustration: Fig. 53. Section of a Branch of Coral. (Lacaze-Duthiers.)]