is8 Mr. Gibson’s Description of an 
three vessels which were deficient. The position of its auri- 
cles and ventricles was peculiar, and the whole heart was in 
a great measure reversed. The two auricles lay in contact, 
and were not separated by the origin of the large vessels. 
The ventricle situated towards the right side of the body 
gave off the aorta ; whilst the pulmonary artery arose from 
the left ventricle, which was contiguous to the heart of the 
left side. These vessels were united bv a ductus arteriosus. 
The pulmonary artery, however, was not situated before the 
aorta at its origin ; it passed behind the superior part of the 
right ventricle, so as to get behind the origin of the aorta, 
W'here it was divided into branches, distributed to the lungs of 
the right side of the chest. At this point also, the ductus 
arteriosus was detached from the pulmonary artery, and fol- 
lowing the direction of the aona upwards, appeared like a 
second arch, placed behind the arch of the aorta. In fact, the 
arch formedby the ductus arteriosus very nearly resembled that 
of the aorta, by sending off a large vessel from its convex side. 
From the arch of the aorta the carotid arteries were given 
off, as distinct branches, but no axillary artery for the arm of 
the right side. This vesstd, with the right vertebral, and the 
inferior thyroid arteries of the right head, were detached from 
the middle of the ductus arteriosus in one trunk, which soon 
divided into three branches. This aorta then descended a 
little, and united to its fellow, from the heart of the left side. 
I shall pass over the smaller vessels derived from the de- 
scending aorta, and only notice, that in the situation of the 
eseliac artery, three or four vessels v/ere given off, crowded 
together : they appeared to be destined for the liver, and for 
the two stomachs, two spleens, and single pancreas. 
