portrait

Description:

Portrait of Monosiga, a choanoflagellate without a visible lorica. A collar of pseudopodia which trap food particles surrounds a central flagellum. The particles are transported to the base of the collar where they are ingested. This is an unusually large specimen. The cell body is usually about 5 microns in length. The nucleus, food vacuoles and contractile vacuole are well seen here. This species is stalked while others are not, the cell body attaching directly to the substrate. From a freshwater pond near Boise, Idaho. Phase contrast.