Definitions
from The Century Dictionary.
- noun The blastopore or primitive mouth-opening of the embryo in the gastrula stage.
Etymologies
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Examples
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The primitive mouth or prostoma is originally a simple round aperture at the lower pole of the long axis; its dorsal lip is above and ventral lip below.
The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876
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In the gastrula-embryos of the mammals, which are much modified cenogenetically, this cleft-shaped prostoma is lengthened so much that it soon traverses the whole of the hinder half of the dorsal shield; as we find in a rabbit embryo of six to eight days (Figure 1.122 pr).
The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876
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This spot corresponds to the original primitive mouth (prostoma or blastoporus).
The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876
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The cavity which is produced in the foetus by this curving is, in each case, the primitive gut (progaster), and its opening the primitive mouth (prostoma).
The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876
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As in all the other animals that form an archigastrula, the whole body is nothing but a simple gastric sac or stomach; its internal cavity is the primitive gut (progaster or archenteron, Figure 1.38 g, 1.35 d), and its aperture the primitive mouth (prostoma or blastoporus, o).
The Evolution of Man — Volume 2 Ernst Heinrich Philipp August Haeckel 1876
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The primitive mouth (prostoma) is closed by the yelk-stopper, P. s partition between the primitive gut cavity
The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876
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This probably occurred in the Platode ancestors of most (or all?) of the Coelomaria; in these the permanent mouth (metastoma) lies at the fore end (oral pole), whereas the primitive mouth (prostoma) lay at the hind end of the bilateral body.
The Evolution of Man — Volume 2 Ernst Heinrich Philipp August Haeckel 1876
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(prostoma) to the internal cavity of the gastrula-body and its opening; because this cavity is the first rudiment of the digestive cavity of the organism, and the opening originally served to take food into it.
The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876
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