The Rim of the Reef ' 



By E. Yale Dawson 



Allan Hancock Foundation, 

 University of Southern California 



[With 8 plates] 



DREDGE DOWN ! The gears of the bow winch mesh ; the great 

 spool turns, and the steel cable pays out as the biological dredge is 

 lowered into the tropical sea. Fifty fathoms below is a submerged, 

 flat-topped mountain, the Gorda bank. We are here to seek what lives 

 on that submarine butte. 



So it was, 20 years ago, when the research vessel Velero III was ex- 

 ploring the strange biota of the Gulf of California. I was, as a fledg- 

 ling marine botanist, witnessing dredging from a ship for the first 

 time in my career. We were over the bank, and now were blindly 

 scraping off a bit of its surface to bring to light the creatures of the 

 dim sea floor, almost at the uttermost limits of light. 



The dredge came up full. Its great bag-load, bulging within a 

 protective chain skirt, was poised for a moment over the sorting 

 screens. The closing cord was cut, and out poured a pile of shiny 

 nodular pebbles, each an inch or two in diameter. But these were 

 strange stones indeed, covered with warts and knobs, and all of a 

 rose-pink color. In fact, there was not a stone in the lot. This was a 

 dredge load of plants — stone plants of the sea — the calcareous red 

 algae known collectively as nullipores. 



In the days of lace cuffs and powdered hair, these curious plants 

 were generally considered to be some kind of inorganic, stalactite- 

 like form. They found their way into "collectors' cabinets" of the 

 time along with corals, worm tubes, walrus tusks, and other novelties 

 of the sea. Linnaeus treated them as coral-like animal forms. Indeed, 

 Lamarck coined their name — nuUipore — to distinguish these forms 

 "without visible pores" from the porous corals. It was not until 1837 

 that the stones were finally and positively recognized as plants. 



Today we recognize calcareous forms in each of the three major 

 groups of marine algae — the green Chlorophyta, the brown Phaeo- 



1 Reprinted by permission from Natural History, vol. 70, No. 6, 1961. 



365 



