The Excretory System of Nautilus

Abstract

Paleontologists trace the nautiloids to an origin from septate monoplacophorans in the Late Cambrian, whereas the coleoids appear to have had a more recent origin, from belemnites. The divergence of these cephalopod lines is so far back in antiquity that major differences are to be expected in both structure and habits. Nevertheless, the groups show functional homology in their excretory apparatus; therefore, a uniform nomenclature for the pericardial and renal appendages has been adopted (Naef, 1913). The existing knowledge of excretion in Nautilus is based entirely on studies of two species: N. pompilius Linnaeus and N. macromphalus Sowerby, with few differences having been noted between the two and every likelihood that excretion in the other few known species will prove to function in much the same fashion.