Fig. 4. Mantle muscle trimethylamine oxide (TMAO, mmol kg^–1) measured according to Wekell and Barnett (1991), minimum depth of occurrence (MDO, m) and capture depth (CD, m) of cephalopods listed according to their phylogenetic associations (see Carlini and Graves, 1999). Values are corrected for the dilution of tissue with extracellular ammonium concentrations in some species (see text). Nodes are numbered for reference in the text. Numbers in parentheses are from Hebard et al. (1982) or Kelly and Yancey (1999).