The development of the veins in the domestic cat (Felis domestica) with especial reference, 1) to the share taken by the supracardinal veins in the development of the postcava and azygos veins and 2) to the interpretation of the variant conditions of the postcava and its tributaries, as found in the adult

This investigation was begun in 1905.Tn the preceding years we had found that the variations or atypical conditions of the venous system observed by Darrach,' McClure2 and others in the adult cat could not all be explained on the basis of the existing knou~ledge of the development of the veins.We therefore determined to study in detail the normal ontogenetic plan of the veins in the cat, with the hope that we might be able to interpret correctly the variant conditions of the venous system which arose as the result of atypical development of the veins.3We have recently extended our observations to a study of the development of the veins in man, the pig and the rat, and while 1 Darrach, W. 1907.Variations in the postcava and its tributaries as observed in 605 examples of the domestic cat.