The aorta gives off a large branch (the anterior aorta) very near its origin, from which arise - first, the left axillary, and afterwards the right axillary and the two carotid arteries.
In the primitive form a single anterior aorta is given off from the ventricle, the two together representing the dorsal blood-vessel of Chaetopods.
In short, the single corporeal element of the Ionian physicists was, to borrow a phrase from Aristotle, a permanent aorta having 7r1cOrj which change; but they either neglected the iraOn or confounded them with the oboia.
The heart is not contained in the pericardium, lies dorsad of the rectum and gives off a single aorta anteriorly.
To the left of the vena cava is the Spigelian lobe, which lies in front of the bodies of the tenth and eleventh thoracic vertebrae, the lesser sac of peritoneum, diaphragm and thoracic aorta intervening.
The gonad is transversely wrinkled and lies between the aorta and the intestine, extending from the pericardium to the anterior end of the body.
The heart in Patella consists of a single auricle (not two as in Haliotis and Fissurella) and a ventricle; the former receives the blood from the branchial vein, the latter distributes it through a large aorta which soon leads into irregular blood-lacunae.
Welch produced oedema of the lungs experimentally by increasing the pressure in the pulmonary vessels by ligature of the aorta and its branches, but this raised the blood pressure only about one-tenth of an atmosphere, while in some of Loeb's experiments the osmotic pressure, due to retained metabolic products, was equal to over thirty atmospheres.
The aortic trunk is very short, sends off the coronary arteries and then the left aorta brachiocephalica, while the rest divides into the right brachiocephalic and the aorta descendens.
The aorta is not independent as in Chitons, but is a sinus like the other channels of the circulation.