7.--SEM photos (A) Spongilla lacustris, gemmulosclere, (B) Spongilla lacustris, microscleres, (C) Spongilla lacuslris, megaclere, (D) Spongilla lacustris,
gemmule, (E) Trochospongilla horrida, gemmulosclere, (F) Trochospongilla horrida, megasclere, (G) Trochospongilla horrida,
gemmuleSorbitol dehydrogenase activity was undetectable in the quiescent
gemmules. During
gemmule germination at 20 [degrees] C, activity increased dramatically to a maximum of 0.2 [micro]mol/min [multiplied by] mg protein at 36 h [ILLUSTRATION FOR FIGURE 4 OMITTED].
In the fall and winter months, the larger framework of the sponge deteriorates and
gemmules form.
This is also a wonderful example of what Karl Popper (1963) called "conjecture and refutation," an intellectual process whereby ideas related to the underlying principle (in this case the
gemmules of pangenesis) are proposed and then subjected to experiment in an attempt to reject them.
Gemmules are asexual reproduction structures of continental sponges produced in dry and otherwise adverse periods of the year (Frost, 1991; Volkmer-Ribeiro and Pauls, 2000).
Nor could he describe how
gemmules were modified, how they were "thrown off," or even what they were.
Existence d'une regulation biochimique de l'eclosion des
gemmules chez les spongillides.
It is, indeed obvious that the presence of
gemmules in the blood can form no necessary part of my hypothesis; for I refer in illustration of it to the lowest animals, such as the Protozoa, which do not possess blood or any vessels; and I refer to plants in which the fluid, when present in the vessels, cannot be considered as true blood.
Sponge identification is based largely on spicule morphology and care was taken to collect specimens bearing
gemmules, as well as somatic tissue.
* Megascleres Gemmoscleres
Gemmules Length Width Length Width Width Min 259 22.94 48.47 9.62 690 Max 336.70 65.49 157.25 34.04 998.20 Ave 307.68 45.94 87.20 25.09 839.43 SD 20.53 7.81 23.05 4.46 72.42 * MCN-POR: 7860 3533, 3534.
the board, with Dalton's odd atoms, Darwin's
gemmules and Lamarck's