NO. 6 ECHINOID DISTRIBUTION AND HABITS — KIER, GRANT 5 



and its echinoid fauna discussed (fig. 3). Depths that were explored 

 range from intertidal along the shore and at exposed parts of the reef, 

 to 110 feet seaward from Molasses Reef. The investigation included 

 the making of several traverses across the various channels, reefs, 

 and sand flats, detailed census-taking in selected small areas, and the 

 less detailed investigation of numerous stations in each of the various 

 environments. 



The echinoid fauna. — Seventeen species of echinoids were observed 

 in the area of study. They belong to several of the major echinoid 

 groups, and inhabit many different environments (table 1) : 



"Regular" echinoids 



Eucidaris tribuloides (Lamarck) 

 Diadema antillarum Philippi 

 Astropygya magnified Clark 

 Arbacia punctulata (Lamarck) 

 Echinometra luctmter (Linnaeus) 

 Echinometra viridis Agassiz 

 Tripneustes ventricosus (Lamarck) 

 Lytechinus variegatus (Lamarck) 

 "Irregular" echinoids 

 Holectypoida 



Echinoneus cyclostomus Leske 

 Clypeasteroida 



Clypeaster rosaceus (Linnaeus) 



Clypeaster subdepressus (Gray) 



Leodia sexiesperforata (Leske) 



Encope michelini Agassiz 

 Spatangoida 



Plagiobrissus grandis (Gmelin) 



Brissus unicolor (Leske) 



Meoma ventricosa (Lamarck) 



Schizaster {Paraster) floridiensis new species 



Living specimens of all these species were observed except Schiz- 

 aster (Paraster) floridiensis. Although we saw only a few specimens 

 of Brissus unicolor and Echinoneus cyclostomus, all the other species 

 were abundantly represented by living individuals. 



Acknowledgments. — It is a pleasure to acknowledge the interest 

 and encouragement of the Smithsonian Institution and the U.S. Geo- 

 logical Survey which gave permission for the publication of this paper, 

 and the financial support of the National Science Foundation by a 

 grant to P. M. Kier through the Smithsonian Institution. John 

 Harms of the Marathon Oil Company, Boulder, Colo., accompanied 

 the authors on most of the dives, and helped greatly in determination 

 of the types of bottom sediments as well as in collecting echinoid 



