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Updated: May 15, 2025
Speaking of the rib, I may add to what I have said about the development of the skeleton, that the number of ribs is just the same in man and woman. In both of them the ribs are formed from the middle germinal layer, and are, from the phylogenetic point of view, lower or ventral vertebral arches.
There were some who scattered as he drew near, and of the less timorous spirits that remained only a few raised dark, sullen glances to encounter his, which was unflinching, passionately contemptuous. Throughout the countless generations that lay behind them the instinct of submission had played its dominant, phylogenetic role. He was the Master. The journey across the seas had not changed that.
As we have already seen, this ancestral form is particularly important. The actual ontogenetic development of the gastrula from the blastula furnishes sound evidence as to the phylogenetic origin of the Gastraea from the Blastaea.
Sixty years ago such a doctrine was excusable, for then nothing was accurately known either of the finer structure of the brain, or of the physiological functions of its separate parts; its elementary organs, the microscopic ganglion-cells, were almost unknown, as was also the cell-soul of the Protista; very imperfect ideas were held as to ontogenetic development, and as to phylogenetic there were none at all.
Increased movement produces hypertrophy, and according to the theory here maintained, not merely enlargement of parts existing, but phylogenetic increase in the number of such parts, here fin rays and their muscles.
With the phylogenetic study of the four higher classes of Vertebrates, which must now engage our attention, we reach much firmer ground and more light in the construction of our genealogy than we have, perhaps, enjoyed up to the present.
Hence it has not yet been possible to arrange these important fossils with any confidence in the ancestral series that descend from the Protamniotes to the Sauropsids on the one side and the Mammals on the other. Opinions are particularly divided as to the place in classification and the phylogenetic significance of the remarkable Theromorpha.
In the lower Vertebrates it develops into a special cavity filled with calcareous crystals, which remains open permanently in some of the primitive fishes, and opens outwards in the upper part of the skull. But in the mammals the labyrinthic appendage degenerates. In these it has only a phylogenetic interest as a rudimentary organ, with no actual physiological significance.
There were some who scattered as he drew near, and of the less timorous spirits that remained only a few raised dark, sullen glances to encounter his, which was unflinching, passionately contemptuous. Throughout the countless generations that lay behind them the instinct of submission had played its dominant, phylogenetic role. He was the Master. The journey across the seas had not changed that.
If the hypothesis which has been presented as an explanation of the genesis and the phenomena of fear be correct, then that hypothesis explains also the emotion of love. If fear be a phylogenetic physical defense or escape which does not result in muscular action, then love is a phylogenetic conjugation without physical action.
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