"the issue of such children taking (equally between or among them per stirpes if more than one) the share, original or accresced, which his, her or their parent would have taken if such parent had survived."
"As regards the whole residue of my means and estate I direct my trustees to divide the same equally between my children the said Robert Livingstone Aitken and Morag Macfarlane Aitken or Brown jointly with the issue who may survive me of such of my children as may have predeceased, the issue of such children taking (equally between or among them per stirpes if more than one) the share, original or accresced, which his, her or their parent would have taken if such parent had survived."
"(Fourth) As regards the whole residue of my means and estate I direct my trustees to divide the same equally between my children the said Robert Livingstone Aitken and Morag Macfarlane Aitken or Brown jointly with the issue who may survive me of such of my children as may have predeceased, the issue of such children taking (equally between or among them per stirpes if more than one) the share, original or accresced, which his, her or their parent would have taken if such parent had survived."