843 



the metamorpliosis of the great anterior veins in Man and Mam- 

 malia, and on the relations existing between the primitive and final 

 condition of these vessels, in different cases, both in their normal 

 arrangement in animals, and their abnormal condition in the human 

 subject. ' 



From an examination of the form and structure of the sinus of the 

 great coronary vein, and of the arrangement of its branches and 

 valves in Man and some of the Mammalia, and from a comparison 

 of those parts with the terminations of the great coronary and other 

 posterior cardiac veins in the other Mammalia, the coronary sinus 

 in Man and one set of Mammals, as the Dog, Cat, and Seal, is shown 

 to be analogous to the loiver part of the left vena cava anterior found 

 in another set, represented by the Elephant, Rabbit and Hedgehog, 

 and to the lower part of the left vena gzygos, found in a third set, as 

 exemplified in the Sheep, Ox and Pig. The great coronary vein, 

 therefore, is shown always to end in a similar way, viz. in a larger 

 muscular venous channel, which, in all cases, ends in the right auri- 

 cle of the heart, by a wide orifice situated in an exactly correspond- 

 ing part of that cavity. 



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- 



