A colony of bryozoans (Membranipora membranacea) on a kelp blade Kelp fronds often carry white spots. Darwin mentioned them, on kelp off Chile, in his bestseller Voyage of the Beagle. This white spot is composed of many cells, grouped around a center. Each cell contains an individual bryozoan, a Lacy Crust Bryozoan or Membranipora membranacea. A single individual is known as a zooid (which is a great scrabble word). Here you can see that the zooids are a filter-feeders, sievi