Fig. 3. Trimethylamine oxide content (y, mmol kg^–1; see Fig. 4) in mantle muscle tissue is significantly correlated with digestive gland lipid content (x) in cephalopods (y=2.90x^1.18, r=0.59, P<0.05). We were unable to analyze trimethylamine oxide (TMAO) content as a function of total lipid content because of the variable presentation of lipid data in the literature. Lipid data were taken from Blanchier and Boucaud-Camou (1984), Hayashi (1989, 1996), Hayashi and Kawasaki (1985), Kristensen (1984), Phillips et al. (2001), Piatkowski and Hagen (1994), Pollero and Iribarne (1988) and Semmens (1998). In many cases, lipid and TMAO data were taken from different species, and possibly different maturity stages, of the same genus. (1) Octopus; (2) Loligo; (3) Galiteuthis; (4) Sepia; (5) Illex; (6) Berryteuthis; (7) Moroteuthis; (8) Gonatopsis; (9) Todarodes; (10) Gonatus. There are conflicting reports regarding the digestive gland lipid content of Thysanoteuthis, a squid that also contains high TMAO concentrations (Hayashi, 1996; Yuneva et al., 1994). Many of the genera plotted here are closely related to each other (see Fig. 4). Therefore, phylogenetic independence of the data should not be assumed.