with the nearer heir, that is, where one of two younger brothers claims against the  other by the assise during the life of the eldest. It is clear that the assise does not  proceed between them for two reasons, first because they are equal in possessory  right and secondly, because the eldest brother who has the mere right is the nearer  heir; nor may anyone be a nearer heir except him to whom the mere right descends,  one or several. Nor in the case of near1 heirs is recourse to be had to the writ of right,  because the mere right descends to neither of them. And since between such persons  the assise does not lie, neither does cosinage, nor does it lie between their heirs.2  Since it does not lie between near heirs, it will not lie between a near and a remote or  a more remote heir, nor consequently will cosinage. Kinsmen may claim by the assise  against strangers on the seisin of their ancestors, and in the degrees to which the  assise of mortdancestor does not extend they may claim by writ of cosinage, within  the limits imposed by time and the requirement of proof, as was said above.34But  suppose that when a relative, a middle or younger brother, is in seisin of an inheritance  descending from a common origin, he transfers the whole or part to a stranger;  the eldest brother and nearer heir brings the assise against the tenant, and the latter  vouches the younger brother to warranty and he warrants; it seems at first sight  that the assise ought to fall because5 the matter has come to a case6 between an  elder brother who is a nearer heir and a younger brother who is a near heir, which  ought to proceed by a writ of right, as though the assise had been brought against a  younger brother found in seisin. 7But in truth, according to some, the assise does not  fall, because the tenant, though he is warranted, does not withdraw from seisin,  but the warrantor8 is bound to defend him in his seisin. Seisin is not taken from the  tenant,9 [for] suppose that when the younger brother or relative is vouched to  warranty he defaults, must not the assise be taken by default against the tenant?  Of course. And so if, when he has warranted, he cannot defend the tenant in his  seisin; the demandant will recover the tenant's seisin and the tenant escambium  from the warrantor. Therefore let the assise proceed10 unless the warrantor can  answer to it and show why it ought not to proceed. But the contrary sometimes is  done.
Exceptions against the writ of cosinage.
 Mutatis mutandis, the same answers and exceptions may be made to a writ of cosinage  as to an assise of mortdancestor, as where it is excepted that the writ of cosinage  does not lie because the parties are co-heirs and the inheritance descends  from a single origin, and that cosinage does not lie any more than the assise.