Fig. 1. Anoxic twitch force relative to twitch force under oxygenation (%) in isolated and electrically paced cardiac strips from: red-eared slider (Trachemys scripta); painted turtle (Chrysemys picta); softshelled turtle (Apalone Spinifera); European viper (Vipera berus); ball python (Python regius); American alligator (Alligator mississippiensis); edible frog (Rana esculenta); marine toad (Bufo marinus); common Carp (Cyprinus carpio); European eel (Anguilla Anguilla); Atlantic cod (Gadus morhua); rainbow trout (Oncorhynchus mykiss); guinea pig (Cavia porcellus); rat (Rattus rattus). Data are obtained from: ¹(Hartmund and Gesser, 1996), ²(Bing et al., 1972), ³(Bobb and Jackson, 2005), ⁴(Overgaard et al., 2005), ⁵(Gesser and Poupa, 1978), ⁶(Zaar et al., 2007), ⁷(W.G. and T.W., unpublished), ⁸(Joseph et al., 2000), ⁹(Andersen et al., 2004), ¹⁰(Gesser, 1977), ¹¹(McDonald and Macleod, 1971). For Python regius, CA is a preparation from Cavum arteriosum, and CP is a preparation from Cavum pulmonale. For Alligator mississippiensis, LV is left ventricle and RV is right ventricle.