1) When the first plane of cleavage coincides with the median plane of the grey crescent, the median plane of the embryo coincides with these two. li]2)|When the first plane of cleavage is at right angles to the median plane of the grey crescent, the median plane of the embryo usually coincides either with the first plane of cleavage or with the median plane of the grey crescent, but sometimes with neither. li]3)|The dorsal lip of the blastopore appears on the grey crescent side of the egg. li]4)|In fifty percent of the cases the first plane of cleavage coincides with the median plane of the grey crescent. In about eight and a half per cent of the cases the second plane of cleavage coincides with the median plane of the grey crescent. In the remaining eggs, the first plane of cleavage lies to one side, or the other, of the middle of the grey crescent, usually near to it. li]5)|The smallest black Gell of the four at the eight cell stage always lies on the crescent side of the egg. When the crescent is bisected by the first cleavage plane, the smallest cell lies in eighteen percent to the right, and in twenty-nine percent to the left. When the first cleavage plane does not bisect the crescent, the smallest cell lies nearest the centre of the crescent.