Unrestricted.2016-11-142011-02-192016-11-141978-12http://hdl.handle.net/2346/21118The primary purpose of this study is to more thoroughly document hybridization and possible introgression between the spadefoot toads (Scaphiopus bombifrons and S_. multiplicatus, using starch gel electrophoresis. Analysis of mating call recordings (Blair, 1955; Bogert, 1960) first suggested the possibility of hybridization between these species. This possibility was further investigated in northwestern Texas oy Forester (1973). On the basis of mating call analysis he classified 6.3% of the animals as natural hybrids and 10.9% as backcross progeny. The two forms have also been found to be compatible in experimental crosses. Interspecific crosses were 78-97% as successful as intraspecific crosses (Littlejohn, 1959; Wasserman, 1964; H. Brown, 1967; Forester, 1969). Forester (1969) found laboratory raised F, hybrid males to exhibit an average fertility of 61.9% as compared with controls.application/pdfengScaphiopusHybridizationBiochemical geneticsDissertation