CHAPTER XI.

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 vein. _The circulation of the yolk-sack._--Previous observations. Various stages. Difference of type in amniotic Vertebrates. _The vascular glands._--Suprarenal and interrenal bodies. Previous investigations. _The suprarenal bodies._--Their structure in the adult. Their development from the sympathetic ganglia. _The interrenal body._--Its structure in the adult. Its independence of suprarenal bodies. Its development.