64 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I49 



2. Tripneustes ventricosus (Lamarck) station 44 (depth 10 feet), on sand in 



sparse turtle grass, with a few blades of grass held onto test ; typically much 

 less completely covered than L. variegatus. 



3. Eroded bank about 1.5 feet high, showing exposed roots of turtle grass at 



station 30 (depth 15 feet). The tangled mat of roots prevents echinoids 

 from burrowing in grassy areas. 



4. Meoma ventricosa (Lamarck) station 21 (depth 25 feet), two specimens in 



turtle grass where their normal habit of burrowing is impossible, hence 

 they are covered by sand grains, except along the petals, in a manner similar 

 to Clypeaster rosaceus. 



5. Meoma ventricosa in sand at station 29 (depth 25 feet) living on the surface 



in the manner of C. rosaceus, partly covered by grains of sand and blades of 

 grass ; a rare habitat for this species. 



Plate 4. CAMOUFLAGED CLYPEASTER ROSACEUS 



1-7. Clypeaster rosaceus (Linnaeus). 



1. Station 22 (depth 30 feet), on sand near edge of grass, holding grass 

 and coarse sand on test. 



2. Station 30 (depth 15 feet), far from grass, on coarse sand bottom, 

 holding coarse sand grains, shells and shell debris, and worm tubes onto 

 test. 



3. Station 21 (depth 25 feet), in sparse grass, covered by shell fragments, 

 coarse sand grains, and a few blades of grass. 



4. Station 29 (depth 25 feet), on coarse sandy bottom, covered with sand 

 and shells including dead test of Brisstts unicolor. 



5. Station 20 (depth 35 feet), on clean, fine- to medium-grained sand, 

 partly covered by sand grains, standing immediately to right of faint outline 

 of buried specimen of C. subdepressus. 



6. Station 29 (depth 25 feet), in dense grass, covered almost exclusively 

 by blades of grass. 



7. Station 21 (depth 25 feet), in coarse sand near grassy patch, test 

 sparsely covered by coarse sand grains and grass, moving by plowing 

 through sand rather than by normal habit of moving on surface. 



1'i.ate 5. MODE OF BURIAL OF CLYPEASTER SUBDEPRESSUS, 

 AND TRAIL OF EN COPE MICHELINI 



1-6, 8. Clypeaster subdepressus (Gray) 



1. Excavated specimen at station 20 (depth 35 feet) begins to rebury 

 itself by passing sand onto the dorsal surface at the anterior, and by moving 

 forward slightly. 



2-4. Forward motion away from knife blade is apparent; sand is passed 

 onto dorsal surface at ends of petals 3 and 4 as well as being passed back- 

 ward from the anterior. 



5. Burial is complete as specimen has moved forward about one length. 



6, 8. Specimen at station 49 (depth 20 feet) buries with minimal forward 

 motion, completing burial in about 4 minutes by passing sand onto dorsal 

 surface along petalous areas. 



