It shall be sufficient for the plaintiff to aver in his declaration that, on some day specified therein (which shall be after his title accrued), he was possessed of the premises claimed, and that, being so possessed thereof, the defendant afterwards, on some day to be stated, entered into such premises, and that he unlawfully withholds from the plaintiff the possession thereof, or exercises acts of ownership thereon or claims title thereto some interest therein, to his damage, such sum as the plaintiff shall state. The plaintiff shall also state whether he claims in fee or for his life, or for the life of another, or for years, specifying such lives, or the duration of such terms; and when he claims an undivided share or interest, he shall state the same. The premises shall be described in the declaration with convenient certainty, so that from such description possession thereof may be delivered.