Identifier: journalofmorphol23wist (find matches)
Title: Journal of morphology
Year: 1912 (1910s)
Authors: Wistar Institute of Anatomy and Biology
Subjects: Morphology Physiology
Publisher: Boston : Ginn & Co.
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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of the alimentary canal camedown through the channel thus opened up, making a kind ofanomalous posterior mesenteric artery. Behind the spleen themain vessel (a.rec.) is continued in the median line down thedorsal side of the rectum to which it gives off several branches,and, at least in some cases, becomes directly continuous andalso anastomoses indirectly with some of the posterior ventralsegmental arteries. The coeliac division of the artery gives rise first to oesophagealbranches, some of the anterior of which may send twigs to theswim-bladder above and the liver below. At about the samelevel there also arises a slender artery (a.he.p.) to the liver which• often .reaches as far as the gall-bladder. This is the principalright posterior hepatic artery. The main vessel, subject toconsiderable variation, gives rise to branches to all the neigh-boring organs and then turns dorsally in the angle on the rightside of the gastro-intestinal junction. As it approaches the 450 C. H. DANFORTH
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Fig. 19 Schema of the coeliaco-mesenteric system THE HEART AND ARTERIES OF POLYODON 451 mouth of the pyloric gland it bifurcates. The anterior divisionbranches palmately into a number of arteries to the stomach,a left posterior hepatic artery, which, as previously stated, anas-tomoses with the anterior hepatics, and a large artery to theanterior part of the pyloric gland. The posterior division breaksup into three branches, one of which supplies the posterior partof the pyloric caeca, one to the small intestine and one to theside of the stomach. As is the case with many other forms the details of distri-bution vary greatly with all of these arteries, and a wide latitudemust be allowed for individual differences. CONCLUSION The foregoing account of the general anatomy of the arterialsystem of Polyodon shows that, while in many respects theganoid type, especially as exemplified by Acipenser, is quiteclearly indicated, there are, nevertheless, some features whichsuggest elasmobranch and

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