212 TABLE OF CONTENTS. 



CHAPTER X. 



THE ALIMENTARY CANAL, pp. 446 459. 



The solid (esophagus. OZsophagus originally hollow. Becomes solid during 

 Stage K. The postanal section of the alimentary tract. Continuity of neural and 

 alimentary canals. Its discovery by Kowalevsky. The postanal section of gut. Its 

 history in Scyllium. Its disappearance. The cloaca and anus. The formation of the 

 cloaca. Its junction with segmental ducts. Abdominal pockets. Anus. The 

 thyroid body. Its formation in region of mandibular arch. It becomes solid. Pre- 

 vious investigations. The pancreas. Arises as diverticulum from dorsal side of 

 duodenum. Its further growth. Formation of duct. The liver. Arises as ventral 

 diverticulum of duodenum. Hepatic cylinders. Comparison with other types. The 

 subnotochordal rod. Its separation from dorsal wall of alimentary canal. The 

 section of it in the trunk. In the head. Its disappearance. Views as to its 

 meaning. 



CHAPTER XL 



THE VASCULAR SYSTEM AND VASCULAR GLANDS, pp. 460 478. 



The heart. Its development. Comparison with other types. Meaning of 

 double formation of heart. The general circulation. The venous system. The 

 primitive condition of. Comparison of, with Amphioxus and Annelids. The cardinal 

 veins. Relations of caudal veiri. The circulation of the yolk-sack. Previous obser- 

 vations. Various stages. Difference of type in amniotic Vertebrates. The vascular 

 glands. Supra-renal and inter-renal bodies. Previous investigations. The supra- 

 renal bodies. Their structure in the adult. Their development from the sympathetic 

 ganglia. The inter-renal body. Its structure in the adult. Its independence of supra- 

 renal bodies. Its development. 



CHAPTER XII. 



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 Elasmobranchs. 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 Miillerian and Wolffian ducts. In female General account. Formation of ovi- 

 duct as nearly solid cord. Hymen. In male Rudimentary Miillerian duct. 

 Comparison of development of Miillerian duct in Birds and Elasmobranchs. 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. Resume, Postscript. 



