328 



DK THOMAS W. SHORE. 



fluence of the right external jugular, right subscapulo-jugular, 

 and right subclavian with the point of junction of the corre- 

 sponding veins of the other side. By means of this vessel the 

 whole of the veins of the right pre-caval system discharged their 

 blood-stream into the left pre-cava, which was the only vessel 

 entering the sinus venosus to drain both sides of the head and 

 both anterior limbs. This transverse connecting vessel is so 

 similar to the innominate vein found in man and the higher 

 mammals (except that it runs from right to left, and the left 

 pre-cava is persistent instead of the reverse, as in mammals), 

 that it may fairly be called by the same name. The accom- 

 panying figure represents roughly the arrangement found. 



r.p.c.v. 



s.sc.v. 



sel.v. 



Fig. 4. — Innominate vein, hf.., heart ; l.p.c.v., left pre-caval vein ; r.p.c.v., re- 

 mains of the right pre-caval vein ; scl. v., subclavian vein ; s.sc.j.v., sub- 

 scapulo-jugular vein ; s.sc.v., subscapular vein ; i.j.v., internal jugular vein ; 

 e.j.v., external jugular vein ; in. v., innominate vein, connecting the conflu- 

 ence of the veins of the right side with the left pre-caval. 



It should be mentioned that the abnormal innominate vein in 

 the specimen under examination was somewhat varicose, having 

 two prominent dilatations upon it. This suggests that the blood 

 did not find a very easy passage through it. It can easily be 

 seen that this must have been the case, for at the point of 

 junction of the innominate with the left pre-cava there would 

 be two currents of blood passing in nearly opposite directions, 

 uniting into a common channel. 



I find it somewhat difficult to account for this abnormality. 

 I thought, at first, that it must be the result of disease, which 

 had led to a closure of an originally normal right pre-cava and 

 the formation of an alternative blood-channel by dilatation of 



