If a class gift in favor of descendants, issue or heirs of the body does not specify the manner in which the property is to be distributed among the family members who comprise that class, the property that comprises the class gift is distributed among the class members who are living when the interest is to take effect in possession or enjoyment. These class members receive shares they would receive under the applicable law of intestate succession if the designated ancestor had died intestate owning the subject matter of the class gift.