Description of Metopus violaceus
provided by BioPedia
Like M. striatus, this species exhibits the reduction of posterior and enlargement of the anterior body parts. The anterior end is rounded, posterior one is narrow, wavy and somewhat rectangular in outline. Somatic kineties (average number 26) are located between distinct pellicular ribs and are very easy to be counted. Each rib is longitudinally striated like in Blepharisma. The buccal cavity of M. violaceus resembles that of M. es not of M. striatus; a cilia-free zone between the perizonal ciliary stripe and adoral membranelles is narrow and indistinct;The undulating membrane is reduced in size if compared with M. striatus. The buccal complex lies in the anterior body part. The cytostome is equatorial. The large spherical macronucleus (16 µm) lies anteriorly, on the level of the buccal cavity. The micronucleus is single. Trichocysts are absent. The body size of M. violaceus is more or less constant, near 115 x 70 µm. It is a beautiful purple colour which is due to a number of scattered food vacuoles filled with rhodobacteria; the anterior body end is dark since numerous refractile bodies are accumulated in this region; posterior body part is always clear and colourless.
