. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. intervals. 0 10 20 30 40 50 60 0 10 20 30 40 50 60 minutes FIGURE 19. Effect of injected lyophilized extracts of eyestalks (shorter-dashed lines), MEX organs (solid lines), and sinus glands (longer-dashed lines) on dispersed red chromatophores (stripes and in- tervals) of eyestalkless prawns. Injections of muscle extracts (dashed and dotted lines) and sea water (dotted lines) were compared. Each point represents the mean of 10 animals; vertical bars: ± 1 SD. Injection: 1 structure equivalent/animal. DISCUSSION General descri
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. intervals. 0 10 20 30 40 50 60 0 10 20 30 40 50 60 minutes FIGURE 19. Effect of injected lyophilized extracts of eyestalks (shorter-dashed lines), MEX organs (solid lines), and sinus glands (longer-dashed lines) on dispersed red chromatophores (stripes and in- tervals) of eyestalkless prawns. Injections of muscle extracts (dashed and dotted lines) and sea water (dotted lines) were compared. Each point represents the mean of 10 animals; vertical bars: ± 1 SD. Injection: 1 structure equivalent/animal. DISCUSSION General description of the MEX organ Like the MTGX organs, the MEX organ appears distinctly at metamorphosis (Bellon-Humbert et al., 1978). Most neurosecretory cells in the medulla externa form a well defined group in Natantia such as Pandalus borealis (Carlisle, 1959), Palaemon serratus (Humbert, 1965; Van Herp et al., 1977), Palaemon paucidens (Hisano, 1974, 1976), and Penaeus japonicus (Nakamura, 1974). However, in other Natantia, such as Typhlatya garciai (Juberthie-Jupeau, 1976) and Atyaephyra desmaresti (Boissou et al., 1976), the neurosecretory cells are more or less scattered in the medulla externa. In other Crustacea, such as the Brachyura (Enami, 1951; Bliss and Welsh, 1952; Matsumoto, 1958; Smith and Naylor, 1972) or Anomura (Farges, 1975a; Bursey, 1975), the MEX organ is more compact. In Macrura, only scattered neurosecretory cells were described in the medulla externa (Durand, 1956; Andrew et al., 1978; Shivers, 1967; Van Herp, 1972). In Crustacea lacking a distinct MEX organ, the neurosecretory cells are mainly in two locations: above and on the opposite side of the sinus gland. In a few Natantia, neurosecretory cells are in the medulla externa near the sinus gland (Boissou et al., 1976). They can aggregate to form a distinct organ, as in Pandalus borealis (Carlisle, 1959). In Palaemon serratus, the MEX organ is localized on the ros- trodorsal edge of the medulla externa, at t
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
