The purpose of this paper is to give a description of the hepatic circulation and associated blood vessels of a 6mm pig embryo. The early work of His and Rochstetter upon the development of the larger veins and ductus venesus opened the way for later investigation in this field. Minot and Lewis devoted their attention to the study of the minute structure of the hepatic and other sinusoids. Thyng has described a pig embryo of 7.8mm; Piper, Ingalls, Mall and Jordan have each described human embryos of lengths varying from 4mm to 7mm, while Schulte and Huntington and McClure have outlined the development of the venous circulation of the cat.