392 C. H. DANFORTH 



Species, one from each order, have been studied: Scaphirhyn- 

 chiis platyrhynchiis, Polyodon spathula, Lepidosteus osseus, 

 Amia calva. Specimens of all these fish have been kept in the 

 aquarium to be killed and injected as needed. Some of them 

 were operated upon and certain vessels tied several days or weeks 

 before the fish was finally killed. About thirty specimens have 

 been studied. A few of them were dissected without injection, 

 i:)ut in most cases a colored starch mass was forced into the dorsal 

 aorta as soon as the fish was killed. By this method all the 

 \^essels considered in the present paper are easil}^ filled. The 

 dissections have been supplemented by a study of serial sections 

 of embryos and pieces of adult heart and liver. 



The account of the conditions found in these four ganoids may 

 be prefaced by a brief statement of the relations of hepatic and 

 coronary arteries in lower forms. In this connection, it may be 

 stated at once that the hepatic arteries described for sharks and 

 skates (e.g. by Cavalie, '04) are the posterior hepatics. These 

 are rather variable vessels, two of which usually arise from the 

 coeliac artery and accompany the portal vein. In addition, other 

 small arteries, from a similar source or from the oesophageal 

 trunk, generally enter the liver. The number and arrangement 

 of these arteries is far from constant even within a single species. 

 In the present study, except for the few points mentioned below, 

 I have found nothing about them calling for special comment. 



A systematic interpretation of the relations of the coronary 

 arteries in fishes was first proposed by T. J. Parker ('84, '86). 

 According to his view, the whole region beneath the pharynx 

 and in front of the pectoral girdle is supplied, typically, b}'' a 

 ]:)air of vessels arising from the subclavian arteries. These ves- 

 sels he designates as hypobranchials. In their course forward 

 they give rise first to posterior (in skates) and then to anterior 

 coronary branches, finally ending in anastomoses with the re- 

 current branches of the efferent branchial arteries. The pos- 

 terior coronary arteries reach the heart by passing into the sep- 

 tum transversum, the anterior by following the aortic bulb 

 backward. Later writers, among whom may be mentioned in 

 particular G. H. Parkei- and K. Davis ('99) and Ferguson ('11), 



