They differ from suborder Cryptobranchoidea as the angular and prearticular bones in their lower jaws are fused, their trunk ribs are bicapitate, and all members use internal fertilization. The female is fertilized by means of a spermatophore, a sperm-containing cap  placed by the male in her cloaca.
This passage describes a group of animals that differ from Cryptobranchoidea in several key features: fused lower jaw bones, bicapitate trunk ribs, and internal fertilization. The female is fertilized through the deposition of a sperm-containing cap (spermatophore) by the male into her cloaca.