black and white portrait

Description :

Anisonema (a nice-owe-knee-ma) acinus Dujardin, 1841. Cell outline is like a grain of barley. Cells are 21 to 40 microns long, 13 to 17 microns wide, flattened with a ventral groove, which diminishes posteriorly. There are about nine longitudinal pellicular grooves on each of the ventral and dorsal faces of the cell. In some cells, the grooves are fine and difficult to see but in a few cells they are deeper. The cells have a chisel-shaped ingestion organelle, which is difficult to observe at times. The anterior flagellum is about 1.5 times cell length and beats freely from side to side. The trailing posterior flagellum is about 1.7 to 3.2 times the length of the cell, is thicker than the anterior flagellum, lies in the ventral groove, and tapers posteriorly. The cells contain diatoms up to 25 microns long and one cell had four diatoms as long as 13 microns The flagellar pocket is located in the left side of the cell and the nucleus is in the right side. The cells glide smoothly, but jerk backwards when changing direction. Commonly observed.