. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DEVELOPMENT OF A SQUID LIGHT ORGAN IBH I '» •'•;- •m^mp-,:f el IS ' ' - iMftv ' •*fe*«^H" V;' • ^ JA- •-'*-•. Figure 9. Transmission electron micrographs of the light organ rudiment from a 16-day embryo (a; stage A28). A. Low magnification view of the epithelium forming the crypts and of surrounding cell layers. The epithelium at this stage is well differentiated, with polarized cells that are similar to those from the light organs of newly hatched juveniles. The nuclei are located toward the basal region of these ce
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DEVELOPMENT OF A SQUID LIGHT ORGAN IBH I '» •'•;- •m^mp-,:f el IS ' ' - iMftv ' •*fe*«^H" V;' • ^ JA- •-'*-•. Figure 9. Transmission electron micrographs of the light organ rudiment from a 16-day embryo (a; stage A28). A. Low magnification view of the epithelium forming the crypts and of surrounding cell layers. The epithelium at this stage is well differentiated, with polarized cells that are similar to those from the light organs of newly hatched juveniles. The nuclei are located toward the basal region of these cells, whereas the apical portion contains numerous mitochondria and bears an extensive brush border. Scale bar = 10 /im. B. High magnification view of the epithelial cells of the same tissue shown in "A" revealing the typical structure of the microvilli and the numerous mitochondria present in the apical portions of these cells. Scale bar = 1 ;um. (is, ink sac; 1, lumen of crypt; m, mitochondrion; n, nucleus of epithelial cell; r. reflector). form two to three days before any surface epithelial cells are ciliated. The accessory tissues Development of the light organ rudiment from the hindgut-ink sac complex results in its central position in the mantle cavity, largely within the funnel. This location may facilitate a rapid infection by maximizing the rudi- ment's exposure to bacteria in the seawater that circulates through the mantle cavity. The ink sac is also able to function as an accessory structure of the light organ, which uses tissues from the ink bladder and reflective wall to direct and control light emission. Pierantoni (1918) reported that the reflector in Sepiola intermedia develops from muscle tissue. However, our ob- servations ofEuprymna scolopes indicate that the reflector cells, or iridophores, do not develop from muscle. Pieran- toni's observations did not benefit from the use of electron microscopy, and he may have interpreted the lam
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
