Fig. 6. The relationships between muscle physiological cross-sectional areas (pCSA) and head length in banded watersnakes (Nerodia fasciata). Dotted lines indicate the slope predicted under a model of geometric similarity (area=2). All slopes were significantly greater than the predicted value of 2 (Table 4). Closed circles indicated individuals <500 mm snout–vent length (SVL) that consume fish almost exclusively and open circles indicate individuals >500 mm SVL that consume frogs almost exclusively. Add. Ex. Sup., adductor externus superficialis; Add. Ex. Med., adductor externus medialis; Ret. Quad., retractor quadratri; Add. Ext. Prof., adductor externus profundus; Prot. Pter., protractor pterygoidei; D. mandibulae, depressor mandibulae; Ret. Pter., retractor pterygoidei.