Euglenophyceae
Trachelomonas is abundant in water rich in organic material. Such water often has low concentration of dissolved oxygen, but the concentration of soluble salts of iron and manganese are much higher. The cell is forming a case transformed of the salts highly insoluble. These compounds give the case its brown colour. Often the cell has an opening where the flagella are coming out. The opening can have a collar like the one on the image. 20-30 my.
Phacus have cells, which are compressed and often take on a leaf-like shape. The cell surface consist of strips running around the organism. The cell is large, around 30-40 my.