. Journal of morphology. 20. 21 490 EMBRYOLOGY OF CRYPTOBRANCHUS 491 morphological axis to an angle of 44 degrees from the vertical;the ventral lip of the blastopore now lies about 24 degrees beyondthe lower pole of the vertical axis. These changes are set forthdiagrammatically in figures 134 to 137. Two quantitative results of considerable importance arebrought to light through the study of these data: (a) the dorsallip of the blastopore has grown downward over the yolk cells fora distance of about 42 degrees; (b) the egg has rotated in theopposite direction about 37 degrees from its position
. Journal of morphology. 20. 21 490 EMBRYOLOGY OF CRYPTOBRANCHUS 491 morphological axis to an angle of 44 degrees from the vertical;the ventral lip of the blastopore now lies about 24 degrees beyondthe lower pole of the vertical axis. These changes are set forthdiagrammatically in figures 134 to 137. Two quantitative results of considerable importance arebrought to light through the study of these data: (a) the dorsallip of the blastopore has grown downward over the yolk cells fora distance of about 42 degrees; (b) the egg has rotated in theopposite direction about 37 degrees from its position at the begin-ning of gastrulation, making a total rotation of 44 degrees. Atfirst, overgrowth is more rapid than rotation; at the time whenthe blastopore has reached the form of a semicircle its dorsal lipis 43 degrees below the horizontal equator. Later, rotation ismore rapid than overgrowth, and at the time when the blastoporehas become a complete circle its dorsal lip has been carried backto a position 20 degrees below t
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Keywords: ., bookcentury1900, bookdecade1, booksubjectphysiology, bookyear1912
