centric filament

Description:

Melosira (mell-o-sigh-ra) is a centric diatom. The cells are like old-style hat boxes, or old-style pill boxes, or like petri-dishes. In Melosira, many cells are joined end to end to create a filament. The less substantial rings on the lower image are where the two halves of the frustule are joined together by the girdle bands, the more visible connections are where two cells are joined together. Each cell has a radial symmetry. As with other diatoms, plastids have chlorophylls a and c and so have a yellow brown colour. The lower picture reveals the individual disc-shaped plastids. Phase contrast.