VI. A system of a “fine” vessels associated with the lymphatics in the cod ( Gadus morrhua )

Abstract In a paper published in 1926 (4) I described, in the head and forepart of the body of the Angler Fish (Lophius piscatorius), “a system of 'fine’ vessels probably of a lymphatic nature.” These vessels formed delicate and intricate networks in the connective tissues around the arteries and lymph channels and were ultimately distributed to the mucous membranes of the mouth, pharynx and gills, to the walls of the arteries, and to the skin. The individual vessels presented a structure similar to that of a small artery and frequently contained blood; but so far as I could observe the system was not connected in any way with the blood vessels, but was continuous through a terminal capillary network with the lymphatic vessels of normal type described by Trois, Sappey, and other older anatomists. In young Teleosteans the lymph circulation has been shown (10, 12) to resemble that of the blood, with an outward flow to the periphery and an inward flow in the reverse direction, necessitating afferent and efferent component vessels. From the facts observed in Lophius, I put forward the suggestion that the “fine” vessels were probably the afferent component of this double-lymph circulation.