Observations on Opisthonecta henneguyi Fauré-Fremiet: Infraciliature, Argyrome, and Myonemic System

The infraciliature, argyrome, and myonemic system of Opisthonecta henneguyi have been examined after impregnation with the Fernández-Galiano silver impregnation method. The oral infraciliature is formed by one haplokinety and three polykineties while the aboral infraciliature is formed by the trochal band—six kinetosomes wide—and the scopula. The trochal band has three fibrillar systems: orally directed fibers, aboral fibers, and oblique fibers. The argyrome is formed by 90 to 135 fine circular striations, which cover the whole organism with the exception of the peristome. The myonemic system is located in two regions: the oral and the aboral ones. The oral myonemic system is formed by a fibrous ring which surrounds the peristome underneath the spiral of the peristomial infraciliature and by a group of fibers which depart from the peristomial disc. The aboral myonemic system is much simpler, and it is formed by fibers which extend radially from the scopula. Biometrical characterizations of the vegetative cells and living cysts were also made, and our data are compared with the results obtained previously by other authors.