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



spines missing. Shallow sand at station 21 (depth of water 25 feet) at edge 

 of sandy area prevents M. ventricosa from burrowing deeply enough to 

 protect themselves. 



2. Specimen at station 21 (depth 25 feet) with spines missing near petals, 

 preventing complete burial. 



3. Specimen at station 21 (depth 25 feet) with spines missing on posterior 

 lateral surface, preventing complete cover by sand, thus inviting further 

 predation. 



4-5. Station 22 (30 feet), timed pair of photographs, indicating speed of 

 burial. 



4. Time 10 :20. Specimen buried to ends of petals. 



5. Time 10:30. Sand being brought up onto test before specimen has 

 burrowed deeply enough for complete burial. 



6. Station 18. Normal specimen in normal habitat, showing manner of 

 leaving petals uncovered (or covered only by coarse particles) to allow free 

 circulation of water for respiration. 



Plate 12. OREASTER RETICULATUS PREYING ON 

 MEOMA VENTRICOSA 



1. As first observed, station 23 (depth 12 feet), Oreaster reticulatus (Linnaeus) 



draped over an immobile specimen of Meoma ventricosa (Lamarck). 



2. As the starfish was lifted off the urchin, its extruded gut was seen to contract 



back into its mouth, whereupon normal burrowing action of the urchin's 

 spines began. Effects on M. ventricosa of this predation by the starfish are 

 shown on plate 13. 



Plate 13. MEOMA VENTRICOSA AND SCHIZ ASTER (PARASTER) 



FLORIDIENSIS 



1-3. Meoma ventricosa (Lamarck). Station 23; USNM E10309. 



1, 2. Adapical, rear view of specimen attacked by starfish (see pi. 12, 

 figs. 1, 2). Note black stain on anterior half of adapical surface (XH)- 



3. View of posterior of same specimen showing etching of plates by 

 secretions of the starfish ( X 1 ) • 



4-6. Schisaster (Paraster) floridiensis Kier and Grant, new species. 



4. View of peristome and phyllodes of holotype (X3); Station 30; 

 USNM E10302. 



5. Apical system of paratype (X 17) ; Station 30; USNM E10303. 



6. Ambulacrum III of holotype (X 6). 



Plate 14. SCHIZASTER (PARASTER) FLORIDIENSIS 



1-9. Schisaster (Paraster) floridiensis Kier and Grant, new species. 



1, 2, 3. Left side, adoral, adapical view of holotype (X 1) ', station 30; 

 USNM E10302. 



4, 5. Left side, adoral view of paratype with spines (X2) ; station 17a; 

 USNM E10303. 



6, 7, 8. Globiferous pedicellaria from specimen in figures 4, 5 (X 50). 



9. Enlarged view of plastron spines of specimen in figures 4, 5 (X 18). 



