Morphologie et Ultrastructure de Spirochona gemmipara Stein, 1852 (Ciliophora,Chonotrichida). II. Appareil Cytoproctal et Système Excréteur de I'Adulte1

ABSTRACT. Examination of the anterior region of Spirochona gemmipara by combined use of interference contrast microscopy, protargol staining, and transmission electron microscopy has revealed the existence of a cytoproctal apparatus and of an excretory system (contractile vacuole complex), that have often been confused with each other and with the cytopharynx. The cytoproctal apparatus is comprised of an external orifice located at the base of the collar, a cytoproctal canal that is about 20 μm long and delimited by a pellicle with alveoli, and the cytoproct itself. The contractile vauole complex is composed of 6–8 sinuous canals, up to 20 μm long, each of which opens to the exterior by a pore situated among the ciliature of the collar. An ostium, which is the internal orifice of each canal, is connected with a contractile vacuole that is contiguous with a well developed tubular spongiome. Although deeply set, the cytoproct and ostia of S. gemmipara do not appear to be basically different from the corresponding structures described in Paramecium and Tetrahymena.