CHAPTER XII.. The Organs of Excretion, Pp. 479-520.

THE ORGANS OF EXCRETION, pp. 479-520.

Previous investigations. Excretory organs and genital ducts in adult. In male.--Kidney and Wolffian body. Wolffian duct. Ureters. Cloaca. Seminal bladders. Rudimentary oviduct. In female.--Wolffian duct. Ureters. Cloaca.--Segmental openings. Glandular tubuli of kidney. Malpighian bodies. Accessory Malpighian bodies. Relations of to segmental tubes. Vasa efferentia. Comparison of Scyllium with other Elasmobranchii. Development of segmental tubes. Their junction with segmental duct. Their division into four segments. Formation of Malpighian bodies. Connection between successive segments. Morphological interest of. Development of Müllerian and Wolffian ducts. In female--General account. Formation of oviduct as nearly solid cord. Hymen. In male--Rudimentary Müllerian duct.--Comparison of development of Müllerian duct in Birds and Elasmobranchii. Own researches. Urinal cloaca. Formation of Wolffian body and kidney proper.--General account. Details of formation of ureters. Vasa efferentia.--Views of Semper and Spengel. Difficulties of Semper's views. Unsatisfactory result of own researches. General homologies. Résumé. Postscript.