<p><strong>Fig. 2.33.</strong> (<strong>A</strong>) <em>Sargassum natans</em> is a brown alga with pneumatocyts (gas floats) that is often found floating in the ocean.</p>

Fig. 2.33. (A) Sargassum natans is a brown alga with pneumatocyts (gas floats) that is often found floating in the ocean.

Image courtesy of James St. John, Flickr