title: Cytology of the renal appendages of Nautilus (Cephalopoda, Tetrabranchiata).
abstract: The renal appendages of tetrabranchiate cephalopods, Nautilus pompilius (L.) and Nautilus macromphalus (G.B. Sow.), were studied using light- and electron-microscopical methods. The appendages, homologous to the renal appendages of dibranchiate cephalopods, possess in both species a folded transporting epithelium characterized by a secreting brush border and a high content of mitochondria and lysosome-like dense bodies as well as a basal labyrinth, and are separated from the blood lacunae by a multilayered lamina basalis. In the extracellular crypt-like infoldings of the epithelium, numerous concentric stratified concrements are found. The results strengthen the hypothesis that these concrements represent mineral-storage structures only found in calcium shell-supporting species within the class Cephalopoda.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000648:ultrastructure; D002467:Cell Nucleus / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D003896:Desmosomes / Q000648:ultrastructure; D005110:Extracellular Space; D007668:Kidney / Q000032:analysis / Q000648:ultrastructure; D008854:Microscopy, Electron; D008974:Mollusca / Q000648:ultrastructure*; D009940:Organoids / Q000648:ultrastructure; D010710:Phosphates / Q000032:analysis; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism
chemical_list: D010710:Phosphates; D010744:Phosphoric Monoester Hydrolases