No. 2.] DEVELOPMENT OF THE HUMAN COELOM. 441 
was necessary to include some observations on lower animals 
to prove my point, but now I can give a complete table of 
human embryos in which the point of origin of the coeliac axis 
is recorded. 
TABLE SHOWING POINT OF ORIGIN OF COELIAC AXIS. 

LENGTH IN 
EMBRYO. MILLIMETERS. ORIGIN OF CoELiaAc Axis. 
No. XII. Zar Opposite 4th cervical nerve.! 
His’s Embryo M 2.6 < 1st dorsal ta 
“ “ B ih “ 2nd “< ‘“ 8 
No. II. as oC Athi)‘ Ks 
His’s Embryo A eS se 6thy i Ge 
No. XLIII. 103} ae rothwames ce 
No. IX. 14. ce 11th se “ 
No. XXII. 18. a Toth ss 6“ 
No. XVII. 16. cs r2thy «<5 “ 
No. LVII. 20. Below 12th e «6 
Adult. ee r2theee cs 6 

1 In the first two embryos the omphalomesenteric artery is noted, and not the 
coeliac axis. 
2 Compare Fig. 15, Plate VI, His’s Atlas, with M4, Pl. VII. 
3 Compare Fig. 35, Plate II, His’s Atlas, with Fig. 1, Plate I. 
4 Compare Figs. 79 and 86, His’s Atlas, with Fig. 4, Plate I. 
The table shows that the arteries arising from the ventral 
side of the aorta to supply the stomach and intestines are con- 
stantly shifting until their definite origin is finally reached. In 
these specimens the omphalomesenteric artery is shifted ahead 
of the coeliac axis. In embryo No. II the omphalomesenteric 
artery has a double origin from the aorta, which indicates that 
this movement may be brought about by a new anastomosis 
forming, which is then followed by an occlusion of the old origin. 
At any rate it is impossible that the whole aorta shifts with the 
abdominal viscera, for it is bound to the vertebrae and muscle 
plates through the segmental arteries. 
The various sections and the reconstruction of embryo No. 
II show the pleural and pericardial cavities still communicating 
freely. The same is true in embryos XIX, XVIII, and IV. 
