5S8 Royal Society, 



The author remarks that a similar view has recently been published 

 by Bardsleben ; but his own observations were completed, and his 

 deductions arrived at, quite independently. 



Reflecting on the above-mentioned analogies and on the known 

 method of development of the great anterior veins in all the Verte- 

 brata, as pointed out by Rathke, from four primitive lateral venous 

 trunks, viz. two anterior or jugular, and two posterior or cardinal 

 veins, the coronary sinus is demonstrated to be the lower persistent 

 portion of the left anterior primitive venous trunk, next to the heart. 

 By Rathke, however, the whole of this left primitive trunk, from the 

 neck down to the heart, is supposed to become occluded and then 

 entirely to disappear in Man, and in such animals as are similarly 

 formed in respect to these great veins ; but the author finds that not 

 only does its lower part persist in a previous condition as the coro- 

 nary sinus, but that other remnants or vestiges of this primitive ve- 

 nous channel are to be found throughout life in Man, and in those 

 animals in which the great anterior veins undergo a like metamor- 

 phosis. 



The inquiry thus opened is then systematically pursued, first, by 

 tracing the details of the metamorphosis of the great anterior veins 

 in the embryos of the Sheep and Guinea Pig, and in the human foetus ; 

 secondly, by a comparison of the adult condition of these great veins 

 in the entire class of Mammalia; and thirdly, by an examination of 

 the occasional varieties of the same vessels met with in the human 

 subject. 



1. Of the development of the great anterior veins. — After describing 

 at length the metamorphosis of these vessels, the author proceeds to 

 give an account of the remnants of the left anterior primitive vein 

 in the adult. 



These are indicated by the following parts, traced from the sum- 

 mit of the left thoracic cavity down to the back of the heart. Out- 

 side the pericardium certain fine bands of fibrous tissue, which descend 

 beneath the pleura, from the trunk of the left superior intercostal 

 vein to the front of the root of the left lung ; and inside the peri- 

 cardium, a fold of the serous membrane which passes down from the 

 left pulmonary artery to the subjacent pulmonary vein, — certain 

 opaque lines or streaks upon the side and back of the left auricle, — 

 a small oblique auricular vein which is continued from those streaks 

 down to the coronary sinus, — and lastly, the coronary sinus itself. 

 The fold of the pericardium, which hitherto has escaped observation, 

 is particularly described. It is named by the author the vestigial 

 fold of the pericardium, or, from its having contained the canal of 

 Cuvier in the embryo, the Cuvierian fold. 



2. Under the second head, a comparison is instituted between the 

 great anterior veins of Man and the Mammalia generally. 



Having remarked that, as high up in the vertebrate scale as Birds, 

 no fundamental alteration occurs from the primitive condition of two 

 anterior and two posterior independent lateral venous trunks, the 

 author remarks that in all Mammalia one characteristic change is 

 met with, viz. the formation of a transverse branch across the root of 

 the neck. 



