The periotic cistern is large and does not protrude into the fenestra. Lungs are present but the ypsiloid cartilage is absent. Two pairs of gill slits are present. The scapula and coracoid bones of the pectoral girdle are fused to form the scapulocoracoid. Vertebral centra are amphicoelous.
Ribs are bicapitate.
Spinal-nerve foramina are absent from all vertebrae. Anterior glomeruli of the kidney are reduced or absent. Reproductive characters Fertilization is internal. Ciliated epithelium is absent from the cloacal tube and anterior cloacal chamber of females. Epidermal lining is present in the anterior cloacal chamber of females.