Medusae of the world . Fig 28 t —Solmaris fiavescens, from life, by the author, at Naples Zoological Station, winter of 1907-08. A. Side view of mature medusa. B. Immature sensory-club. C. Fully-developed sensory-club. D. Tentacle. E. Stomach-margin show-ing female gonad. F. Diagrammatic section of medusa. and flat while those of the subumbrella entoderm are very high and large. The tentacles growout as wide basal bulbs from the margin and finally the bell grows out as a ring beneath andbetween the tentacle-bulbs. The mouth breaks through and the medusa is thus formed from the actinula. . The
Medusae of the world . Fig 28 t —Solmaris fiavescens, from life, by the author, at Naples Zoological Station, winter of 1907-08. A. Side view of mature medusa. B. Immature sensory-club. C. Fully-developed sensory-club. D. Tentacle. E. Stomach-margin show-ing female gonad. F. Diagrammatic section of medusa. and flat while those of the subumbrella entoderm are very high and large. The tentacles growout as wide basal bulbs from the margin and finally the bell grows out as a ring beneath andbetween the tentacle-bulbs. The mouth breaks through and the medusa is thus formed from the actinula. . The origination of the primitive, entoderm cells through division from the inner ends otthe superficial cells of the blastula recalls the condition observed in Liriope. 436 MEDUS-ffi OF THE WORLD. According to Maas, if the egg be cut into two when in the 2-cell stage, each cell finallydevelops into a small, normal planula and medusa. If the 8-cell stage be separated into a « exnr Fig. 286.—Solmaris fiavescens. Interradial section, drawn by the author, at Naples Zoological Station. em, cord of entoderm at the bell-margin. e*,exumbrella. exnr, exumbrella nerve-ring, gon, male gonad, st, centralstomach, su, subumbrella. v, velum. Ectodermal nuclei are shown in solid black and entodermal nuclei arerepresented as circles. piece with 4 small and another with 4 large cells, the large-cell piece develops irregularly andthe small cells degenerate. A meridional cut through the 8 or 12-cell stage gives a medusawith only local irregularity.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectcnidari, bookyear1910
