. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PHOTOKINESIS IN SPONGE LARVAE 333 r>. •' ;*•'- • . ;.;-jil •-'. *"•' ' ' ^ l^& 6fr^ V: yi&iferi -i «i -:;1 . , ' JM1* ^ _-- v. >' »• .- , -. i JjfcfT 3^#*-if ^M^K^B |p^.; •«.-. i^yf;' vf; C^^, ^• ^f] jT ' ,C » A .«.•>•» ,->. -j ; Figure 8. Ultrastructure of the posterior pole of Reneira sp. larvae, (a) The posterior pole (PP) is formed in pan of large mucus-like cells (me) that protrude slightly from the posterior end (arrowheads). The pigment ring (PRg. dashed line) is formed of columnar epitheli
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PHOTOKINESIS IN SPONGE LARVAE 333 r>. •' ;*•'- • . ;.;-jil •-'. *"•' ' ' ^ l^& 6fr^ V: yi&iferi -i «i -:;1 . , ' JM1* ^ _-- v. >' »• .- , -. i JjfcfT 3^#*-if ^M^K^B |p^.; •«.-. i^yf;' vf; C^^, ^• ^f] jT ' ,C » A .«.•>•» ,->. -j ; Figure 8. Ultrastructure of the posterior pole of Reneira sp. larvae, (a) The posterior pole (PP) is formed in pan of large mucus-like cells (me) that protrude slightly from the posterior end (arrowheads). The pigment ring (PRg. dashed line) is formed of columnar epithelial cells with protrusions (arrow) at their apical surface. These cells contain numerous pigment vesicles (pv) throughout their length and in the apical protrusions. The long posterior cilia (LPC) arise primarily from the anterior-most of these cells. Magnification of the region in the box is shown in Figure 9a. Mitochondria, in; basal bodies of the cilia, bb: nucleus, n. Bar: 5 jxm. (b) A scanning electron micrograph of the posterior pole of a larva that has been fixed while exposed to an abrupt increase in light intensity to cause the long posterior cilia to straighten. Note also that the mucus-like cells (me) protrude slightly from the posterior end (arrowhead), and that most long posterior cilia (LPC) are anterior to the pigment-filled protrusions (arrow). Magnification of the region in the box is shown in (c). Bar: 100 /urn. (c) A scanning electron micrograph of the region of the pigment ring shown in the box in (b). Mucus-like cells (me) protrude from the posterior pole, and pigment-tilled protrusions (arrow ) lie at the base of. and slightly posterior to, the long posterior cilia (LPC). Bar: 20 /urn. the number of pigmented cells nor the general histology of the posterior end in older larvae changed. The structure of the basal bodies and of the basal portions of the long posterior cilia did not appear to be different from those of the short later
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
