Volvox aureus green alga colonies. Volvox is a very large motile colony, common in ponds and lakes. Volvox colonies contain 500 to several thousand biflagellate cells arranged at the periphery of a mucilage shell. Inside of several colonies there are young colonies. One colony with zygotes inside, the color of these resting stages is orange-red. Microscopic contrast method : Darkfield. Capturing device: DSLR Canon 5DMk2 with Microscope adaption. Captured field width : 2.1 mm. Magnification on Sensor : 17x