The effect of heavy metals on photosynthesis and loss of cell potassium in two species of marine algae,Dunaliella tertiolecta and Phaeodactylum tricornutum

Observations on sixth-stage nauplius (pre-cyprid) of the barnacle Balanus eberneus Gould treated with L-proline-3,4-H³ suggest that the cement gland in this stage is a functional organ with considerable biosynthetic activity; the activity of the cement glands in the cyprid similarly treated is relatively low, ceasing gradually during, and completely after, metamorphosis. In the early phases of this stage, the glands become highly vacuolated (degenerate), and disappear completely in 3 days. The origin of the cement apparatus in the newly metamorphosed barnacle is discussed.