11. A Systematic Study of the Main Arteries in the Region of the Heart. Aves: Piciformes*

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Abstract
Summary.: Eight species of Ramphastidæ, 11 species of Capitonidæ, six species of Bucconidæ, two species of Indicatoridæ, and 45 species of Picidæ were studied, and descriptions with diagrams of the main arteries in the region of the neck and thorax prepared. Suggestive differences in the arrangement‐patterns of the arteries were recorded with reference to the basic Order pattern and the Family variation. Presence of the ligamentous vestiges of the left radix aortæ, right ductus botalli, and right ductus caroticus were noted along with the presence of a patent ductus caroticus in Dryobates v. villosus. Possible phyletic relationships between other orders of birds were indicated by the arterial arrangement. All families of the Picidæ were found to be “laevo‐carotidinæ” whereas in the Coraciiformes some families were “lævo‐carotidinæ” while others were “bicarotidinæ normales.” The ductus shawi was shown to be the functionally modified ductus caroticus and was found to be a vessel which results from anastomoses with other smaller arteries which form in situ during middle to late embryogeny. The tendency for a large number of anastomoses of major embryonic vessels, with a few pertinent examples, was noted.