NO. 6 ECHINOID DISTRIBUTION AND HABITS — KIER, GRANT 9 



Encidaris tribuloides (on and tinder rocks), Echinometra lucunter 

 (numerous in holes in rocks, and under rocks), Diadema antillarum 

 (relatively small, numerous under rocks and around edges of rocks), 

 Tripneustes ventricosus (one juvenile under rock). In addition, each 

 rock that was turned over revealed several active brittle stars 

 scurrying for cover. 



Permanently underwater, just offshore. — (Stations 7, 8, 9, 34, 35, 

 48) nearly flat rock bottom covered with thin layer of calcareous 

 sand ; water depth 4-8 feet ; numerous loggerhead and basket sponges, 

 alcyonarian and large and small scleractinian corals, patches of sparse 

 turtle grass (Thalassia), patches of algae. Echinoids : Lytechinus 

 variegatus (in grass), Clypeaster rosaceus (in grass and on sand). 



Rock bottom of artificial channel at station 40 ; depth about 6 feet, 

 edged by mangroves, has numerous Diadema antillarum attaining 

 large size, living in recesses on bottom, and on vertical rocky irregular 

 sides, and among lower parts of mangrove roots ; this is partly 

 intertidal. 



Inshore edge of Hazvk Channel. — (Stations 33, 47) sand bottom, 

 mostly covered with turtle grass, few bare patches; depth 10-15 feet; 

 water typically murky; echinoids: Lytechinus variegatus and 

 Clypeaster rosaceus abundant in grass, a few small solitary Diadema 

 antillarum. 



Shallows just inshore from Rodiguez Key; (stations 3, 4, 5) depth 

 4-10 feet; sand bottom with large areas of turtle grass (Thalassia), 

 calcareous algae (Halimeda), merman's brush (Pennicillus), brown 

 algae, widely scattered loggerhead and basket sponges, small staghorn 

 and brain corals imbedded in sand, buried clams (Area), holothurians, 

 brittle stars, and echinoids : Diadema antillarum (solitary and in 

 groups of up to 50), Lytechinus variegatus (in grass), Echinometra 

 lucunter and E. viridis (under clumps of sponge, coral, and shells), 

 Clypeaster rosaceus (in grass and on bare sand). Detailed survey of 

 100 square feet in sparse turtle grass at station 3 (depth 4 feet) pro- 

 duced the following echinoids : 



Lytechinus variegatus — 7 alive 



Echinometra lucunter and E. viridis — 5 alive, under clumps 



Clypeaster rosaceus — 4 alive, 2 dead 



L. variegatus and C. rosaceus live on the sand bottom, individuals 

 about 1.5-2 feet apart but without apparent segregation as to species. 

 About 20 feet from this surveyed area, in an area 15x5 feet, at the 

 same depth (4 feet) were 90 small and medium size D. antillarum, in 

 one group of 50, one of 20, and two groups of about 10 each, living 

 on the sand bottom in short, sparse turtle grass (pi. 2, fig. 4). 



