1. M. Sarà and L. Liaci. Boll. Zool.31, 55 (1964).
2. D. Castiello, G. Cimino, S. De Rosa, S. De Stefano, G. Izzo and G. Sodano, in: Biologie des Spongiaires, p. 413. Ed. C. Levi and N. Boury-Esnault C.N.R.S., Paris 1979.
3. D. Castiello, G. Cimino, S. De Rosa, S. De Stefano and G. Sodano, Tetrahedron Lett.21, 5047 (1980).
4. PMR δ 2.56 (H-1, d, J 2 Hz), 4.84 (H-3, bd, J 5 Hz), 5.62 (H-4, dd, J 15 and 5 Hz), 5.90 (H-5, dt, J 15 and 6 Hz); CMR δ 73.9 (C-1), 62.7 (C-3), 134.0 (C-4), 128.7 (C-5), 31.8 (C-6). PMR δ 6.20 (H-2, dt, J 15 and 6 Hz), 5.40 (H-3, dd, J 15 and 2 Hz), 5.20 (H-6, bs); CMR δ 33.2 (C-1), 145.5 (C-2), 109.0 (C-3), 52.8 (C-6), 18.7 (C-9).
5. Obviously the position of the terminal functions can be reversed.