02 July 1982
Vol 217, Issue 4554

About The Cover

Advanced larva of the sea urchin, Strongylocentrotus purpuratus. This larva was grown in the laboratory and had been fed for about 6 weeks at the time the photograph was taken. It is about 0.8 millimeter across. The stomach can be seen filled with ingested algae and to the left of the stomach is the large ventral rudiment of the juvenile sea urchin that emerged a few days later upon metamorphosis. The parallel structures in the rudiment are the developing tube feet, still in a folded position. See page 17. [Photo by Patrick Leahy, California Institute of Technology, Pasadena 91125]