1. An angiocardiographic study has been made of Myxine glutinosa, using modern cineradiographic instrumentation. In addition to the heart, vessels in the branchial region have been studied.
2. The topography of the heart chambers and their filling and emptying have been described. The frequency of the heart at body temperature, 8-100° C., was found to be about 30 beats per minute.
3. Results are presented that support the assumption that the gill sacs and theirducts, as well as striated muscles in the branchial region, take an active part in the propulsion of blood.
4. The phenomenon of extravasation or circulation in lacunar spaces (blood sinuses in direct communication with the true blood-vessels) has been demonstrated. The described muscular activity in the branchial region seems to promote the return of blood from these sinuses to the heart.