. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 216 M. TELFORD AND R, MOOI Ciliary currents Currents generated by the ciliary bands on the spines flow between the spine shafts in a pattern common to all the specimens observed (Fig. 4). Fresh seawater can enter the spaces between the spines anywhere except places at which flow leaves the test, but the primary entry points of ambient water seem to be at the center of the aboral surface (Fig. 4A). Centrifugal flow then continues down- ward towards the periphery of the test (ambitus). Cur- rents flowing down the centers of th
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 216 M. TELFORD AND R, MOOI Ciliary currents Currents generated by the ciliary bands on the spines flow between the spine shafts in a pattern common to all the specimens observed (Fig. 4). Fresh seawater can enter the spaces between the spines anywhere except places at which flow leaves the test, but the primary entry points of ambient water seem to be at the center of the aboral surface (Fig. 4A). Centrifugal flow then continues down- ward towards the periphery of the test (ambitus). Cur- rents flowing down the centers of the ambulacra flow cir- cumferentially for a short distance until they leave the petaloids by passing between the respiratory podia. Par- ticularly strong flow is associated with the anal sulcus area, at which currents sweep across the periproctal plates and then along the sulcus to the ambitus. Some flow away from the test was observed at the edge of the hooded region just above the periproct, and at the ambi- tus below the periproct (Fig. 4A). However, the vast ma- jority of the flow continues around the ambitus and onto the oral surface. Anteriorly on the oral surface, the currents flow cen- tripetally until they reach the mouth; then they converge and flow downwards away from the center of the oral surface. Posteriorly, the currents also converge, this time at a point in the posterior region of the naked zone. This area of convergence is characterized by additional down- ward flow away from the test. Strong currents of water that did not leave the echinoid at the peristomial region of convergence were seen to travel on either side of the peristome and then along the center of the naked zone directly towards the posterior region of convergence (Fig. 4B). Ciliary currents were never observed to augment the feeding process, and were in fact very active in com- pletely removing particulate material from the test sur- face, and in providing continuous current over the respi- rator
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
