Crux Ansata (Lat.). The handled cross,T; whereas the tau is T, in this form, and the oldest Egyptian cross or the tat is thus +. The crux ansata was the symbol of immortality, but the tat-cross was that of spirit-matter and had the significance of a sexual emblem. The crux ansata was the foremost symbol in the Egyptian Masonry instituted by Count Cagliostro; and Masons must have indeed forgotten the primitive significance of their highest symbols, if some of their authorities still insist that the crux ansata is only a combination of the cteis (or yoni) and phallus (or lingham). Far from this. The handle or ansa had a double significance, but never a phallic one; as an attribute of Isis it was the mundane circle; as symbol of law on the breast of a mummy it was that of immortality, of an endless and beginningless eternity, that which descends upon and grows out of the plane of material nature, the horizontal feminine line, surmounting the vertical male line—the fructifying male principle in nature or spirit. Without the handle the crux ansata became the tau T, which, left by itself, is an androgyne symbol, and becomes purely phallic or sexual only when it takes the shape +.
Source: H.P.Blavatsky - The Theosophical Glossary