RELATION OF AUTERIEft IN COMMON GANOTDS 



:i\)7 



the median line below the aortu. The coronary arteries, which 

 follow the aorta back, give rise to branches that may be definiteh' 

 identified as ventral coronaries and othei-s that may, with less 

 (certainty, be classed as dorsal coronaries. 



he])idosteus shows little in conmion with the preceding forms, 

 bnt does jiresent some similarity to the condition found in Amia. 



br.3 br.4 sub aoe da. oe. 



cor abd. thd. add. thv 



Fig. 3 Tlic coi-diuir^' Mild licpatic arlci'ics of Ijcpidoslcu.s. m. niifcr'ior coi-o- 

 iiary artcM'v. Othcf lc(tci-.s as in ijiiuri' 1. 



AMIA 



Like Lepidosteus, Amia has neither ])ostei'ior coronary- nor 

 anterior hepatic arteries. The anterioi- coronaries arise from a 

 median hypobranchial artery, as desci-il)ed by Parker and Davis 

 ('99). The hypobranchial itself, however, may be derived, as 

 shown in the figure, from two connnissin"a] arteries instead of 

 the one usually described. Dorsal aiid ventral coronary arteries 

 may be I'ecognized in the bi'anches that I'un along the u])pei' and 

 lower aspe(^t of the aorta, l)\it thei'e seems to l>e no fundjimeiitnl 

 difference between them. The remaining arteries in Amia call 

 foi' no special mention in this connection. 



It will a]3pear from the descriptions that there arc^ among the 

 ganoids two different scluMues for supplying arteriaJ blood to the 

 he.'irt .'Old li\(M'. One, i-(^]iresented by Lepidosteus and .\mia, 



