HUNT, T. C., and ROWLEY, A. F. 1986. Studies on the reticuloendothelial system of the dogfish Scyliorhinus canicula. Endocytic activity of fixed cells in the spleen and liver. Can. J. Zool. 65: 1759-1769. The role of the spleen and liver of the lesser spotted dogfish, Scyliorhinus canicula, in the clearance of a range of materials, including colloidal carbon, latex beads, sheep red blood cells, bacteria, and dextran, was examined. The spleen was particularly important in the clearance process. Smaller particulates, such as carbon, were sequestered by the highly endocytic macrophages of the ellipsoids, while larger particles, for example, bacteria and sheep red blood cells, were mainly taken up by the fixed macrophages of the red pulp. An increase in the numbers of the eosinophilic G 1 granulocytes in the red pulp of the spleen was observed following injection of the particulates. In the liver, fixed cells, probably homologous to mammalian Kupffer cells, were involved in clearance and participated in endocytosis of carbon and latex. Additionally, all of the injected particulates were internalized by cells (frequently seen to also contain melanin granules) lying within nonsinusoidal blood vessels in the hepatic parenchyma. Often, but especially in fish injected with bacteria, these phagocytic cells appeared trapped along with free bacteria, within large clumps of circulatory blood cells in the vessels. The presence of the injected materials in the spleen and liver was evident at 30 min and increased up to 1 week. The ultimate localization and differential uptake of the injected materials, and the relative importance of the spleen and liver in the clearance of these materials are discussed.HUNT, T. C., et ROWLEY, A. F. 1986. Studies on the reticuloendothelial system of the dogfish Scyliorhinus canicula. Endocytic activity of fixed cells in the spleen and liver. Can. J. Zool. 65 : 1759-1769. Le r61e de la rate et du foie dans la clearance mdtabolique d'un certain nombre de substances (carbone colloi'dal, billes de latex, Crythrocytes de moutons, bactCries, dextran), a Ct C examink chez le requin Scyliorhinus canicula. La rate joue un r61e particulierement important dans le processus. Les particules plus fines, particules de carbone par exemple, sont sCquestrCes par les macrophages des ellipsoi'des qui assurent une endocytose efficace, alors que les particules plus grosses, bactCries et Crythrocytes de mouton par exemple, sont absorbdes surtout par les macrophages fixes de la pulpe rouge. On remarque une augmentation du nombre de granulocytes Cosinophiles GI dans la pulpe rouge de la rate apres injection des particules. Dans le foie, des cellules fixes, probablement homologues des cellules de Kupffer des mammiferes, jouent un r61e dans la clearance et elles assurent I'endocytose du carbone et du latex. De plus, tous les types de particules injectCes sont Cgalement sCquestrCs par des cellules (qui contiennent aussi souvent des granules de mClanine) situCes dans les vaisseaux sanguins (pas dans les sinusoi'des) du paren...