. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. A21B A21A. sub-term erm | Jerm jelly-polyp palpon term 1 ^^,'c"" sub-term sub-term term Text-fig. 27. Physalia physalis. Early growth stages (hypothetical) of branches of a gonodendron. A later growth stage of fig. F{d. PI. XXII, fig. 2) is shown in PI. XXII, fig. 5. sub-term = sub-terminal section, term = terminal section, 1, 2, 3 etc. = successive dichotomies, Ax, A2, AJ, A21A, etc. = successive buddings. Jelly-polyps (PI. XXI) As stated on page 348 there is at the base of each termi
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. A21B A21A. sub-term erm | Jerm jelly-polyp palpon term 1 ^^,'c"" sub-term sub-term term Text-fig. 27. Physalia physalis. Early growth stages (hypothetical) of branches of a gonodendron. A later growth stage of fig. F{d. PI. XXII, fig. 2) is shown in PI. XXII, fig. 5. sub-term = sub-terminal section, term = terminal section, 1, 2, 3 etc. = successive dichotomies, Ax, A2, AJ, A21A, etc. = successive buddings. Jelly-polyps (PI. XXI) As stated on page 348 there is at the base of each terminal branchlet a palpon which has at its base a jelly-polyp. These are well shown in PL XXI, figs. 1, 2, 6, 7. It is necessary to understand the regular type of branching just described in the gonodendra in order to demonstrate that the jelly-polyps are not vestigial stalks left after the nectophores have dropped off, an erroneous interpretation put forward by Huxley, Haeckel and Chun. In the older growth-stages, both jelly-polyp and nectophore-stalk look much alike (PI. XXI, fig. 3). This resemblance of the oldest known growth-stage of these two buds is due to the fact that in each the endodermal lumen becomes relatively reduced at the same time as the mesogloea becomes very much thicker (PI. XXI, fig. 3). In both cases the endodermal canal—now almost occluded—comes to lie on the abaxial side, next to the ectodermal fold (PL XXI, fig. 6) except sub-terminally, where it lies centrally to link up with the sub-umbrella of the nectophore and the tip of the jelly-polyp. This structural resemblance between the basal parts of these two kinds of buds—one a medusoid and the other, once thought to be a polyp, but now shown to be a reduced nectophore—was for long inex- 7-2. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the origi
Size: 1764px × 1417px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
