. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. LUMINESCENCE IN HIPPOPODIUS 489. FIGURE 14. Conduction routes in the nectophore. All stimulating points (St) and cuts (dotted lines) are on the front (abaxial) side of the nectophore. Cut A is an incision through the exumbrellar ectoderm around the marginal ring separating the ectoderm within the ring, on which point Stl and St2 lie, from that outside, where St3 lies. Cut B destroys the axial canal at first point of entry into the subumbrella. separating the subumbrellar endo- derm from the endoderm of the axial side. A shoc
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. LUMINESCENCE IN HIPPOPODIUS 489. FIGURE 14. Conduction routes in the nectophore. All stimulating points (St) and cuts (dotted lines) are on the front (abaxial) side of the nectophore. Cut A is an incision through the exumbrellar ectoderm around the marginal ring separating the ectoderm within the ring, on which point Stl and St2 lie, from that outside, where St3 lies. Cut B destroys the axial canal at first point of entry into the subumbrella. separating the subumbrellar endo- derm from the endoderm of the axial side. A shock at point Stl on the subumbrellar surface stimulates both the ectoderm and the endodermal lamella which lies close beneath it. This ectoderm is inexcitable, however, so the effect is simply that of exciting the endoderm. The experimental results are described in the text (h represents a horn; pr: prong; pv: pseudovelum; r: rete; v: velum). that invade both areas. The polarization of ecto-endodermal conduction at the margin may therefore have no functional significance, since impulses have another route by which to pass to the exumbrella from the subumbrella. Conduction between the nectophore and stem does not appear to involve direct epithelial pathways. A "translation" step intervenes, by which epithelial signals excite nervous activity in the stem tissue at its junction with the nectophore. Likewise, nervous activity in the stem appears to be translated into epithelial impulses in the nectophore. These epithelio-neural and neuro- epithelial transfer steps do not operate on a one-for-one basis, and may require facilitation. Details of these interactions will be presented elsewhere (D. Carre and G. O. Mackie, unpublished). Morphological data An electron microscopic survey of the conducting and contracting tissues has been carried out in order to verify previous histological accounts, and to extend them particularly with regard to junctional structure (Fig. 16). The e
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
