Filling up of casual vacancies.

When any vacancy occurs in the office of a member (other than an ex-officio member) of any authority or other body of the University before the expiry of the term of office of such member, the vacancy shall be filled up, as soon conveniently as may be, by nomination, appointment or, as the case may be, co-option of a member who shall hold office so long only as the member in whose place he has been nominated, appointed or co-opted, would have held it, if the vacancy had not occurred.