The heart of the 20mm. pig embryo.
The present article is one of a series planned by Professor Franklin P. Johnson describing the anatomy of the 20mm. pig. This series, it is intended, shall supplement the descriptions of the 12 mm. pig by F. T. Lewis and that of the 7.8 mm. pig by F. W. Thyng. In this paper is described the anatomy of the heart and its vessels, particular attention being paid to morphology. It includes descriptions of the form, size, and position and relations of the heart; its chambers, valves, atrio-ventricular bundle, and coronary vessels. It was first intended to include the whole vascular system, but a description of the peripheral vessels has been deferred to another paper. For the basis of this work, embryo No. 1702 of the Harvard Embryological Collection, which was kindly loaned by Professor C. W. Minot, has been used. Other embryos of approximately the same age have constantly been referred to.