4. At the same period the viscera are visible, but the stomach, and intestines, and the veins from the heart still appear to extend towards the navel. From the navel a vein appears to extend upon the membrane which encloses the yolk, and the yolk itself is at this period fluid, and more abundant than in its natural state. The other extends to the membrane which encloses the whole membrane containing the embryo, and the membrane of the yolk and the fluid between them, and when the young birds have grown a little more, part of the yolk goes to one end, and part to the other, and between them is the fluid white; but the white is still below the lower part of the yolk, where it was at first, but at the tenth day the white disappears, for it has become small, viscid, thick, and rather yellow. 5. This is the position of all the parts: the first and last part adjoining the shell is the membrane of the egg, not the membrane of the shell, but beneath this. This contains the fluid white; within this is the young bird, and a membrane surrounding it, and separating it from the fluid; beneath the embryo is the yolk, to which one of the veins extends, and the other to the white which encloses it. A membrane containing a fluid resembling sanies encloses the whole, and then another membrane which surrounds the embryo itself, as I observed, and separates it from the fluid. Below this the yolk, enclosed in another membrane, which is reached by the umbilical cord from the heart, and the great vein, so that the embryo does not appear to be in either of the fluids. 6. About the twentieth day, if the hatching has been delayed beyond this period, the young bird is able to chirp when moved externally, and if the shell is taken off, by this time also it is downy. The head is placed over the right leg upon the side, and the wing is over the head. At this period the chorion-like membrane is visible, which is united with the lowest membrane of the shell, to which one of the umbilical cords passes, and the young bird is complete. The other chorion-like membrane is also visible, enclosing the yolk. To this the other umbilical cord extends. Both of these cords are attached to the heart and the great vein. At the same period the cord which is attached to one chorion falls off, and is separated from the animal, but the one which passes to the yolk remains suspended from the young bird by a thin bowel, and a considerable portion of the yolk is contained in the young bird, and some of it is found in the stomach.