Remnants of oviducts, or Müllerian ducts, are common in the male Anura; they are best developed in _Bufo_, much reduced, and individually absent, in _Rana_. In _Bombinator_ each duct is restricted to its upper or abdominal portion, and is attached to the vestigial headward extension of Leydig's duct. Lastly in _Discoglossus_ and in _Alytes_ all traces of oviducts seem to have vanished, at least in the adult males. It is interesting to note that in the arrangement of the urino-genital ducts the Discoglossidae are the most advanced of all Amphibia, instead of showing the most primitive conditions. This is rather unexpected, but is paralleled by the epichordal type of the vertebral column. The oviducts of the Apoda and Urodela remain more or less straight; in the viviparous species they form uterus-like dilatations. In the Anura they become greatly elongated during the {52}breeding season and form many convolutions. As a rule each oviduct opens separately into the cloaca, but in _Hyla_ they have one unpaired opening, while in _Bufo_ and _Alytes_ the lower parts of both oviducts are themselves confluent. All Amphibia possess FAT-BODIES. They consist of richly vascularised lymphatic tissue, the meshes of which are filled with lymph-cells, globules of fat and oil. In the Apoda these bodies lie laterally to the generative glands, and along the posterior half of the kidneys. In the Urodela they accompany the anterior half of the kidney. In the Anura they are lobate, and are placed upon the anterior end of the testes or ovaries. Their exact function is still doubtful, but it is intimately connected with that of the generative glands. The old notion, that they are simply stores of fat for the nourishment of the animal during hibernation, is quite untenable. The fat-bodies do not decrease during this period, on the contrary they attain their fullest size in the spring at the time of the rapidly awaking activity of the reproductive organs, and they enable considerable quantities of sperma and of eggs to be produced and ripened without detriment to, or utter exhaustion of, the animals, which often spawn before they have had time or opportunity to feed. After the spawning season the fat-bodies have dwindled down to inconspicuous dimensions. Lastly, there is in some Anura, hitherto observed in _Bufo_ only, a mysterious organ, intercalated between the fat-body and the testis or ovary. This is "Bidder's organ" and it seems to be a rudimentary ovary, or rather that upper, anterior portion of the whole organ which undergoes retrogressive metamorphosis. It disappears in old female toads, but in the males it sometimes assumes a size equal to, or surpassing that of the testes. The males are in this respect hermaphrodite, and cases are known in which parts of the generative glands have developed testes and egg-bearing ovaries.