None. Begins: It is generally admitted that one of the most remarkable forms of life discovered by the Challenger expedition is the polychæte worm, Syllis ramosa, in which the body branches laterally, these branches again sending off shoots into the passages of the sponge in which the worm lives. The result is an intricate net-work (except that, of course, the branches do not anastomose), and as each branch ends in an anus there is a large number of ani to one head. The two specimens obtained by the Challenger lived in the bases of hexactinellid sponges found at 140 fathoms depth in the Arafura Sea and in the Philippines at 95 fathoms.