. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 330 M. TELFORD ET FIGURE 3. Diagramatic longitudinal sections through (A) Clypeaster rosaceus and (B) C. subdepres- sus showing epibenthic habit, degree of aboral surface cover, and relative positions of the peristomes. A, anus; I, infundibulum; L, lantern; S, test support pillar; T, tooth; Th, piece of dead Thalassia. convergence on the midline. So far as we could tell, passage of material over the aboral surface was in no way related to the feeding activity of C. subdepressus. The aboral surface is largely covered by
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 330 M. TELFORD ET FIGURE 3. Diagramatic longitudinal sections through (A) Clypeaster rosaceus and (B) C. subdepres- sus showing epibenthic habit, degree of aboral surface cover, and relative positions of the peristomes. A, anus; I, infundibulum; L, lantern; S, test support pillar; T, tooth; Th, piece of dead Thalassia. convergence on the midline. So far as we could tell, passage of material over the aboral surface was in no way related to the feeding activity of C. subdepressus. The aboral surface is largely covered by a thick mucus sheath secreted by the podia and spines. When the animals are resting or moving slowly, this sheath may be almost stationary but at times of greater activity it is moved steadily towards the rear by the action of spines, and it is replenished at the front and sides. Small sand grains and other fine particulate materials are trapped in the mucus, move with it, and are re- turned to the sediment as the sheet drops off the posterior edge. When complete, very few particles penetrate the sheet. Those which were pushed through with forceps, to fall among the spine bases, were rapidly moved to the ambitus by the combined ac- tion of pedicellariae and ciliary currents. The pedicellariae are so numerous that every spine is accessible to at least half a dozen of them. During feeding, both species collected particulate material by means of oral sur- face accessory podia. Particles were then passed from podium to podium towards the mouth, sometimes without reference to the food grooves and sometimes along them. Transported particles moved up the slope of the infundibulum which, especially in C. subdepressus, became quite crowded with food material. The food grooves are rather unspecialized, the spines and podia flanking them being little differentiated from those adjacent to them. Small particles (100-200 /urn) tended to become incor- porated into indistinct mucus-bound stran
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
