. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ^ '•». Figure 5. Movements of a cell of Pruruceiitrum micuns in relation to repeated hood lifts hy an aclinotrocha. The view is of the dorsolateral side of the larva. The black bar is to one side of the algal cell. Numbers at the upper right of each frame are time in seconds from the first frame in the sequence. The hood had completed lifts at and s. In each case the algal cell was drawn inward to the edge of the hood. Lowering of the hood had produced maximum outward excursions of the algal cell at
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ^ '•». Figure 5. Movements of a cell of Pruruceiitrum micuns in relation to repeated hood lifts hy an aclinotrocha. The view is of the dorsolateral side of the larva. The black bar is to one side of the algal cell. Numbers at the upper right of each frame are time in seconds from the first frame in the sequence. The hood had completed lifts at and s. In each case the algal cell was drawn inward to the edge of the hood. Lowering of the hood had produced maximum outward excursions of the algal cell at and s. The scale was undetermined. (This larva had sustained damage that shortened the body posterior to the tentacles.) f V A second hypothesis is that particles are halted by a sieve formed by stationary laterofrontal cilia, as observed for the cyphonautes larva of bryozoans (Strathmann and McEdward, 1986). The actinotrochas do have laterofrontal cilia (Hay-Schmidt, 1989), but our videorecorded images were insufficiently clear for direct observation of sieving by those cilia. The laterofrontal cilia of the tentacles may be sensory (Strathmann, 1973; Gilmour, 1978; Hay- Schmidt, 1989;Lacalli, 1990; Pardos etal., 1991). Instead of or in addition to acting as a sieve, the laterofrontal cilia could detect the particles and trigger the hood lift. Our observations do not separate the effect of a hood lift from the effect of the cilia in transporting particles toward the mouth. Raising the oral hood could change the currents generated by the cilia on the hood margin and other cilia of the oral region by changing distances from the body wall and other cilia. It is also possible that changes in ciliary beat coincide with movements of the oral hood. Thus changes in ciliary currents could contrib- ute to a change in the movement of a particle when the hood lifts. However, the simplest explanation is that the hood itself is moving the water and the particle with it du
Size: 2138px × 1169px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
