312 Mil. F. E. BEDDARD ox THK [Nov. 3, 



artery gives off sevei-al bi-anches of varying importance as to size. 

 The first of these is one of the smallest in size but greatest in 

 morphological importance ; it arises from where the artery has 

 begun very definitely to bend backwards, and is directed upwards 

 towards the dorsal side of the body. It is, in fact, the Dtictus 

 Botalli, the link between this aortic arch and the pi'eceding one. 

 The principal branch in point of size arises from the same side 

 and a little fui-thei- on. This closely accompanies the pulmonary 

 artery, so closely that it is bound up in the same sheath and had 

 to be carefully dissected away. It gives off two branches on the 

 dorsal side and one on the ventral side. At the base of the lung 

 this vessel abandons its close companionship with the main 

 pulmonary trunk, and runs along a different face of the lung. 

 This branch is not figured by Osawa. 



The Duettos Sotalli, as has been already mentioned, joins a 

 branch from the thii-d vascular arch, and the conjoined vessels 

 give off a number of twigs to the adjacent musculature, which are 

 illustrated in the drawing submitted herewith (text-fig. 33, p. 3 11 ) * . 

 I take it that this series of small vessels, M'hich have been I'ef eixed 

 to as existing in all of the vascular arches, are the arteries which 

 oiiginaUy supplied the branchia. There is a final fact about the 

 pulmonary aitery, to which I desire to refer. The right pulmonaiy 

 artery gives off a branch which supplies the oesophagus. I could 

 find no corresponding branch on the left side, and indeed I do not 

 think that one exists. I imagine that the various small bi-anches 

 of the pulmonary arch and of its large branch collectively represent 

 the cutaneous tiunk of the Amphibia generally. 



The Pulmonary vein might easily escape attention, as it is not 

 at all apparent on a dissection. It lies in fact directly above the 

 vena cava inferior, and being of much smaller dimensions, it is 

 completely covered by that vein when the animal is dissected 

 from the ventral surface. The two pulmonary veins join each 

 other just within the pericardium, where they form a tolerably 

 wide trunk. The common pulmonai-y vein increases in diameter 

 as it passes along the sinus venosus, and finally opens into the 

 smaller division of the auricle. There is thus at least a partial 

 separation of arterial and venous blood in the heart. 



Intercostal Arteries and Veins. — The very deep fold of peri- 

 toneum which ties down the aorta to the dorsal parietes enables 

 me to see clearly the course of the intercostal arteries and of 

 certain intercostal veins, which are presumably branches of the 

 portal system in the abdominal region. Of the arteries I counted 

 seven, four of which are arranged in paii-s, while the three 

 remaining arteries are not so disposed. They arise fi'om the 

 aorta, however, definitely on one side or the other ; they are not 

 median in origin. Furthermore, the points of entrance into the 

 thickness of the parietes are not median ; they are on one side or 

 the other, and in the case of the paired arteries they enter the 



* Prof. Osawa represpiits nothing more tliaii a simple transverse Ductus Botalli 

 uniting- the arteries in question. 



