The numerous exceptions to the fourth class of contingent re mainders are comprehended in what is called the Rule in Shelley's case, of which a complete exposition is given in Fearne 's ' Essay on Contingent Remainders ; ' and in Preston's ' Treatise on Estates' (vol. i.). The nature of this rule may be generally stated as follows :—If lands are limited, either by deed or will, to a man for life, and after his death to his heirs or the heirs of his body, the limitation to the heirs would appear to be a contingent remainder according to the definition of the fourth class of contingent remainders, for the heirs are persons who cannot be ascertained till the death of the person to whom the estate for life is given. But it is an old rule of law that the estate so limited to the heirs or the heirs of the body takes immediate effect as an estate in the ancestor, and therefore, in the former case, A takes an estate of freehold with a vested remainder in fee. His life estate is consequently merged in his remainder in fee, and lie becomes tenant in fee simple in possession. If an estate for life, or an estate tail, I is interposed between the estate for life to the ancestor and the re mainder to his heirs or the heirs of his body, still this remainder is vested in the ancestor, just in the same way as if it were limited to him and his heirs, or to him and the heirs of his body. Thus when A takes an estate for life, remainder to B for life, remainder to C in tail, remainder to the right heirs of A, this ultimate remainder is a vested remainder in fee in A, and, after his death and the determination of the intermediate estates, his heir will take by descent. But cases within this rule are not so properly exceptions, as cases which by the operation of the rule are excluded from the fourth class of contingent remainders.
There is another exception to the fourth class, which is allowed in devises, where it can be clearly inferred from the particular expres sions in the will, that a limitation to the heir special of a person then living is intended as a designation of a particular person. In such case the remainder will vest ; for the conclusion is, not that the testator intended to limit the estate by way of contingent remainder to such person as should be ascertained to be heir by the death of his ancestor, but that he intended by the word " heir," accompanied with the other expressions in the will, to designate a particular person.
A contingent remainder may intervene between the particular estate and other limitations over, and yet the subsequent limitations may be vested, if made to a person in ease, provided the contingent limita tion is not in fee simple. The contingent remainder itself may also vest, and then become an estate interposed between the particular estate and the subsequent vested limitations, if the contingency hap pens during the existence of the particular estate. If in the same
conveyance an estate is limited to A for life, followed by a contingent remainder and a subsequent limitation to A and his heirs, or A and the heirs of his body, this last limitation, though executed under the rule in Shelley's case, is still so executed as to allow the contingent remainder to interpose as a vested estate when the contingency happens. A subsequent contingent limitation may vest before a preceding one, but it follows from what has been said that the preceding one is still capable of vesting.
Lands may be so limited as to be subject to a general power of ap pointment. In such cases, the general power of appointment will not prevent the estates limited in default of appointment from vesting ; though the due exercise of the power will divest them.
A contingent remainder may be limited generally upon any event, except in such cases as the following :—the contingent event being illegal ; the remote possibility of the contingent event ; and the con dition enuring to defeat the preceding estate. These subjects are fully discussed by Fearne (c. 2).
It will be collected from what has been said that a contingent re inainder of freehold must be preceded by a vested estate of freehold ; for if there is no precedent vested estate of freehold, and the freehold remainder is contingent, the freehold either remains in the grantor, and therefore is not transferred to any one else, or it is transferred in some remainder which is limited after the contingent remainder, and which, being therefore vested in possession, precludes all possibility of the vesting of the contingent estate, which by the terms of the limita tion must precede it. This rule as to the necessity of a vested freehold estate to support a contingent remainder, applies both to limitations of uses and of estates limited at common law.
It will also appear from the definitions of contingent remainders that they must vest, that is, the conditions on which they are limited must be fulfilled, during the continuance of the particular estate or immediately on its determination. One of the cases in which such remainders were formerly liable to fail under the fourth class of con tingent remainders, was in the case of such limitations as to A for life, and to his first and other sons in tail. Originally a posthumous son could not take, but such child is now for this and several other pur poses considered as a person in esse during the period of pregnancy. When a contingent remainder is limited to several in a conveyance to uses or by a devise, such remainder will vest in the first person in whom it can vest, but it will divest in due proportions in favour of other persons who are included in the limitations, and who become capable of taking before the determination of the particular estate ; and such persons may take as joint tenants, though their estates vest at different times.