The Cephalic Muscles of Branchiate Amphibians: 1. The Dipnoi; 2. The Anuran Tadpole; 3. The Urodele Larva; 4. The Perennibranchiate Urodele; 5. Review. The Cephalic Muscles of the Abranchiate Amphibians: 1. The Adult Caducibranchiate Urodeles; 2. The Adult Anura; 3. The Adult Caecilians; 4. Review; Appendix. The Laryngeal Muscles of the Amphibians. The Skulls of the Amphibians: 1. The skull of Neoceratodus; 2. The Skull in the Euamphibia; 3. The Skull in the Embolomeri. The Origin of the Amphibia: 1. General considerations; 2. The Evidence of the Cephalic Muscles on the Phylogeny of the Amphibia; 3. The Serial Homology of certain of the Bones in the Skulls of the Amphibia, and their bearing on the Evolution of the Class.