48 



CHARLES F. W. McCLURE AND GEORGE S. HUNTINGTON 



VII. TABLE SHOWING EELATIVE FEEQUENCY WITH WHICH THE 



DIFFEBENT TYPES OF VENA CAVA POSTEEIOE HAVE BEEN 



OBSEEVED TO OCCUE IN THE ADULT CAT AND IN MAN 



VIII. GENEEAL CONCLUSIONS 



In the preceding pages we have demonstrated that all 

 atypical conditions of the vena cava posterior (inferior) 

 found in the adult cat and in man can be interpreted and 

 explained on the basis of the modifications of a common onto- 

 genetic plan of the veins. An analysis of the composite dia- 

 gram (fig. 1) of the embryonic veins shows that seventeen 

 (17) predictable forms of atypical venae cavae occur. In 

 conclusion, we may state that every atypical condition of the 

 vena cava thus far observed in the cat and in man falls within 

 one of the seventeen predictable Types of caval veins. 



