. Elements of zoology, to accompany the field and laboratory study of animals. Zoology. THE ANCESTRY OF VEHTEBliA' 297 - <U b£ TI ^ ' improbable that such a change in position could have occurred; but when we recall that the ancestors of vertel^rates, like modern prechor- dates, probably assumed a vertical position, it is not so cUfRcult to under- stand how the tran- sition may have occurred. The mouth must have changed from the neural side (on which the nerve cord lies) to the hffimal side (that of the heart), and we find that in the larva of Amphioxus it lies on neither the neural nor
. Elements of zoology, to accompany the field and laboratory study of animals. Zoology. THE ANCESTRY OF VEHTEBliA' 297 - <U b£ TI ^ ' improbable that such a change in position could have occurred; but when we recall that the ancestors of vertel^rates, like modern prechor- dates, probably assumed a vertical position, it is not so cUfRcult to under- stand how the tran- sition may have occurred. The mouth must have changed from the neural side (on which the nerve cord lies) to the hffimal side (that of the heart), and we find that in the larva of Amphioxus it lies on neither the neural nor haemal side, but halfway between; a significant position if it indicates a stage in the ances- tral movement of the mouth from the neural to the haemal Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Davenport, Charles Benedict, 1866-1944; Davenport, Gertrude Anna Crotty, 1866- joint author. New York, Macmillan
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1911
