Description of Colpoda henneguyi
provided by BioPedia
Colpodid ciliate 30-80 microns long, usually about 60-70 x 50 microns. Shape very characteristic: preorally often distinctly wider than postorally, usually broadest at vestibular level. Right margin (dorsal side) slightly to distinctly notched in posterior third, left margin similarly so close behind oral apparatus, resulting in narrowed, block-shaped postoral portion; notches caused by distinet diagonal groove, become indistinct or disappear entirely in overnourished and morbid specimens. Thus when in doubt starve cells for some hours. Entrance to vestibulum indented semicircularly. Slightly to markedly (2.5:1) flattened, depending on degree of nourishment. Postoral sack distinct extends on dorsal side. Macronucleus spherical to slightly ellipsoid, between vestibulum and dorsal side coated in almost all populations and specimens by many 1-2 microns sized, bright, yellowish globules. Nucleolus reticulate. Micronucleus lenticular, about 3 x 2 microns in vivo, with thick membrane appearing fused with that surrounding macronucleus. Contractile vacuole near median of cell, with indistinct collecting canals, releases contents 5 times per minute at 15 degrees centigrade. Usually single excretory pore near centre of posterior pole; but some cells have 2-3 pores. Extrusomes about 1.2 x 0.6 microns, do not form distinct cortical layer in vivo arranged in 2-3 rows between somatic kineties, stain red with methyl green-pyronin, but are not released. Feeds on bacteria, fungal spores, amoebal cysts and humus particles. Remains motionless already a few minutes after removal from sample, i.e. holds onto detrital masses or soil particles by means of the cilia. This remarkable behaviour not only enables good photographs of live cells, but also distinguishes C. henneguyi rather well from other species in the group which remain motionless, if at all, for only a few seconds. Somatic ciliature without peculiarities. Polymerization of dikinetids in postoral kinetics eztends to dorsal side. Vestibulum relatively large and with 2-4 vestibular kineties. Left polykinetid crescentic, protrudes slightly from vestibulum, forms an angle of about 45 degrees with longitudinal axis of body. Right polykinetid crescentic, very similar to that of other members of group.
