\'OL. XLV.] PHILOSOPHICAL TRANSACTIONS. 571 



The heart of the smaller child was single, but above a third larger than it na- 

 turally ought to be; out of which the ascending arteries are very regular and 

 natural; but there was scarcely any vestige of lungs in this child on the right 

 side of the thorax, and but a small portion of the pulmonary substance in the 

 left. The descending trunk of the aorta is very small in comparison of the 

 other; yet goes down regularly towards the extremities, except the internal iliac 

 arteries, which were obliterated and degenerated into ligaments, while the ex- 

 ternals continued down, as abovesaid ; for only the iliacs of the larger foetus took 

 place in the umbilical cord, which was the reason that there were only 2 arteries 

 in it; so that, though both children received nourishment by the division of the 

 canal from the liver to the venae cavse, yet the superfluous blood of both could 

 be sent back to the placenta no other way than by the internal iliacs of the larger 

 child. 



The descending branches of the vena cava entered as usual, on the right sides 

 into the auricles; but those of the left join in one trunk, pass round the left 

 auricle, and enter into the right close by the cava ascendens, which is of a na- 

 tural size, and very regular up to the diaphragm, from which it extends a full 

 inch before it reaches the auricle. The kidneys differ a little in size from each 

 other; yet these, with the other urinary and also the uterine parts in general, are 

 in good order; but the most remarkable lusus of nature in these subjects, is an 

 artery which arises from the aorta about the place of the coeliac of the one child, 

 running along before the liver, and is inserted into the same place of the aorta 

 of the other. It was much larger than any other artery in either child, and be- 

 stowed branches on the stomach, mesentery, and mesocolon, being about 5 

 inches long ; for there were neither coeliac nor mesenteric arteries, according to 

 nature in either child. 



[Then follow some speculations on the formation of monsters, which are 

 deemed not of sufficient importance to be retained.] 



Explanation of the drawings representing the two children joined together. — • 

 Fig. 8, pi. 9, shows a back view of the intestinal canal of each child, from the 

 stomach to the anus ; a, a, the stomach of each ; b, b, the duodenum ; c, c, part 

 of the jejunum which is common to both children; d, the remaining part of the 

 jejunum formed into a sacculus, out of which arises e, e, the ileum of each 

 child; f, f, the ccecum of each; g, g, the colon of each; h, h, the rectum 

 of each. 



Fig. 1, pi. 10, is a fore view of the other viscera, and vascular system of both 

 children: a, the umbilical vein entering into the liver, which is formed of that 

 of each child preternaturally conjoined; b, b, the lungs of the larger child; c, 

 the heart, which has a bifid apex, and of which each ventricle has its particular 

 pericardium, from the sulcus that divided it; f, tlie great vessels arising out of 



4d 2 



