273 



The later condition of such of these veins as are involved in the 

 Wolffian body is this : 



Torpedo 

 (51 mm) 



Necturus 

 (adult) 



Rabbit 



(adult) 



Connection between the 

 caudal vein and 



a) mesonephrie azygos 



b) subcardinal vein 

 Connection between the 



azygos vein and 



a) mesonephrie azygos 



b) subcardinal vein 

 Mesonephrie azygos veins 



persist 



Subcardinal veins 

 fuse 



connect with the liver 

 persist 



Sinusoids 



Large 



Sinusoidal 



Sinusoidal 

 Very large 

 Throughout 

 (Sinusoidal 

 anteriorly) 



At the genital 



sinus 

 On the left 

 Throughout 

 and receive 

 genital veins 



Permanent 



Large 

 Sinusoidal 



Large 

 Large 

 Throughout 



Throughout 



Eight 



Throughout 

 and receive 

 genital veins 



Permanent 



Large on right side; dis- 

 appears on left*) 

 Disappears 



Disappears 

 Disappears 

 On right as vena cava inf. 



from iliac to renal vein ; 



on both sides as parts of 



genital and of ant. trans. 



lumbar veins 



At left renal vein 



Eight 



On right as vena cava inf. 

 from renal vein lo liver. 

 On left as suprarenal 

 vein 



Disappear except as con- 

 nection between subcar- 

 dinal and raes. azygos at 

 level of renal veins ; and 

 as part of genital veins 



Heart. 

 The embryonic blood vessels connecting the vitelline veins with 

 the aortae may conveniently be called the cardiac vessels. By their 

 fusion a single cardiac vessel is produced, which then is invaded on 

 all sides by columns of heart muscle. Thus a sinusoidal sponge is 

 formed, enclosing a central cavity. Outside of the cardiac muscle 

 there is a connective tissue envelope, the epicardium. From the sinus 

 venosus coronary veins develop as sprouts, ascending in the epicardium 

 toward the bulbus arteriosus. Arterial offshoots descend the bulbus 

 and form capillary anastomoses with the coronary veins. Thus the 

 heart has a superficial capillary and a deep sinusoidal circulation, 

 wholly different in their development. This may be observed either in 

 rabbits or torpedoes. 



1) In this table either arm of the loop around the ureter is re- 

 ferred to as mesonephrie azygos. 



Anat. Anz. XXV, Aufsätze. 18 



