Ultrastructure of a marine nematode, Chromadorina germanica (Buetschli, 1874)

Summary

The caudal gland apparatus in Chromadorina germanica females usually consists of three unicellular units surrounded by a basal lamina; sometimes a fourth cell of unknown nature, lacking a duct, is present in the gland region. The following observations were made in these studies: In the specimens examined the nuclei of the anterior, cells are large with prominent nucleolus. The nucleus of the posterior cell is smaller and contains condensed chromatin. When a fourth nucleus is present., its morphology resembles that of the posterior gland cell. The cytoplasm is rich in rER and mitochondria; typical Golgi bodies were not observed. Filamentous microvilli containing dense particles project in the ramifications of the gland lumen; secretory granules are formed by condensation of these particles. In the posterior part of the tail the duct of the anterior cell is located ventrally and those of the posterior cells dorso-sublaterally, with a longitudinal muscle in between. This muscle is thought to be the spinneret retractor. The tail extremity consists of a terminal tube, separated from the gland ducts by the spinneret plug. Two very short subterminal setae are implanted on the tube. A possible secretory cycle is deduced from light microscopic observations and from the differences in ultrastructure in the 3 gland cells.