Uploaded on May 4, 2010
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Budding In Hydra
Budding in hydra has received the attention of only a few
investigators. Our principal information as to the origin of the
bud is derived from Lang's' account. He describes the bud as
beginning by an increase in volume and division of the interstitial
cells. After the ectoderm becomes thickened, the mesoglea dis
appears and the cells pass from the ectoderm into the endoderm.
This process continues until the ectoderm becomes reduced to its
normal thickness. The mesoglea then reforms and a cavity ap
pears in the thickened endoderm, which becomes the enteron of
the new individual.
The main object of the present paper will be to give a brief
account of the origin and development of the buds in hydra, more
especially their manner of growth and what cells contribute most
to their rapid formation.
The species studied, Hydra viridis and Hydra sp.? (Brauer)
differ somewhat from Lang's account. The mesoglea does not
disappear and the ectodermal cells do not pass into the endoderm.
The bud, however, begins by an increase in volume and division
of the interstitial cells. After they have increased once or twice
in volume, as shown in Fig. i, there is a slight outbulging of
the ectoderm, which is scarcely perceptible. represents
the condition of the interstitial, ectodermal and endodermal cells
in the origin of the bud as they appear more highly magnified.
A few mitotic figures are visible. No amitotic divisions were
observed. The endodermal cells contain numerous food particles,
which may pass intact through the mesoglea into the ectoderm.
The cells directly concerned in the formation of the bud are well
supplied with food, while the remaining cells of the parent hydra
show a scarcity. Many of the endodermal cells in the distal half
of the hydra have a glandular appearance and are most active.
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