. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 35o DISCOVERY REPORTS final branchlet. In Text-fig. 27f the second pro-bud A2 of fig. d has developed into similar terminal and sub-terminal sections (A21B, Ag1^). New pro-buds always arise sub-terminally, and as a rule at a point opposite a jelly-polyp. Some- times they form terminal-type, sometimes sub-terminal-type sections. PI. XXII, figs. 6 and 8 show slightly later stages of development that might have been reached later on by the specimen shown in Text-fig. 27 f. The first palpon, which i
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 35o DISCOVERY REPORTS final branchlet. In Text-fig. 27f the second pro-bud A2 of fig. d has developed into similar terminal and sub-terminal sections (A21B, Ag1^). New pro-buds always arise sub-terminally, and as a rule at a point opposite a jelly-polyp. Some- times they form terminal-type, sometimes sub-terminal-type sections. PI. XXII, figs. 6 and 8 show slightly later stages of development that might have been reached later on by the specimen shown in Text-fig. 27 f. The first palpon, which is morphologically the terminal part of the branchlet, has grown very much more rapidly than the sub-terminal parts. PI. XXII, fig. 11 shows how complicated the young genital clusters look when the branchlets lie side by side. Those shown in PI. XXII, fig. 8 have been separated, flattened out and mounted on a microscope PALPON JELLY-POLYP Text-fig. 26. Physalia physalis. Schematic drawing of a branch of a gonodendron to show repetitive pattern of growth. br = branch, sub-term = sub-terminal section, term = terminal section. It will be noticed at this stage, which I call the Key-stage from a fancied resemblance to the lever- steps of a simple key, that the buds of both terminal and sub-terminal sections stand out more or less at right-angles to the long axes. In the next stage (PI. XXIII, fig. 2) they are more or less parallel to one another and stand at an angle of 45° to the common axis. The jelly-polyps are no longer little conical projections but have become more cylindrical; and the nectophore bud shows its medusoid nature. The gonophores are now conspicuous objects. PI. XXIII, fig. 2 (right) may usefully be compared with its earlier counterpart shown on the right-hand of PI. XXII, fig. 4. Stages of growth intermediate between those shown in PI. XXIII, figs. 1 and 2 may be seen in PI. XXII, figs. 10, 11 . The most mature stage of growth of branchlets of the gonodend
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