Chapter 17 focused on the tetrapods as a whole, particularly how the pectoral and pectoral fin/forelimb muscles have evolved during the transitions from nonmammalian tetrapods to monotremes, to therian mammals, and to placentals, including modern humans. Therefore, most taxa included in Tables 17.1 through 17.3 were mammals. The two other taxa, Ambystoma and Timon, were included in those tables to show the general hypotheses of homology between the muscles of the mammalian taxa and the muscles of amphibians and lepidosaurs. In Chapter 18, we will turn our focus to the major groups of limbed amphibians and reptiles: urodeles, anurans, lepidosaurs, crocodylians, birds, and turtles. The tables included in Chapter 18 will include Ambystoma and Timon as representative members of urodelan amphibians and of lepidosaurian reptiles as well as Bufo, Caiman, Gallus, and Trachemys as representative members of anuran amphibians and of crocodylians, birds, and turtles, respectively (adult extant caecilian amphibians lack a pectoral girdle and lack limbs, and thus, their pectoral and forelimb musculature is extremely reduced: these amphibians will therefore not be discussed in the present chapter; see, e.g., Carroll 2007). Many anatomical works have provided information about the pectoral and forelimb muscles of amphibians and reptiles (e.g., Mivart 1869; Humphry 1872a,b; Fürbringer 1876; Ecker 1889; Gaupp 1896; McMurrich 1903a,b; Ribbing 1907, 1938; Romer 1922, 1924, 1944; Howell 1935, 1936b,c; Haines 1939, 1950; Straus 1942; Sullivan 1962, 1967; Grim 1971; Hudson et al. 1972; Walker 1973; Holmes 1977; Ghetie et al. 1981; Duellman and Trueb 1986; Russell 1988; Manzano 1996; Burton 1998; Dilkes 1999; Wyneken 2001; Meers 2003; Walthall and Ashley-Ross 2006; Maxwell and Larsson 2007; Russell and Bauer 2008). However, most of these works have focused on a specific taxon and/or a specific pectoral or forelimb region, and none of them has provided detailed information about the homologies of all the pectoral and forelimb muscles of urodeles, anurans, lepidosaurs, crocodylians, birds, and turtles.