. Bulletin - United States National Museum. Science. D Fig. 12.—Cyclosalpa pinnata, aggregated zooid, diagrams showing the forward rota- tion AND TRANSFORMATION IN SHAPE OF THE DORSAL EYE. FROM METCALF AND JOHNSON (1905); e, eye; gg, ganglion; r indicates in each case the same region of the eye. A, A DORSAL VIEW OF THE GANGLION AND THE EYE OF A SOLITARY SALPA. THE HORSESHOE- SHAPED EYE IS ABOVE THE GANGLION, WITH THE ENDS OF THE HORSESHOE POINTING FORWARD. THE DORSAL EYE OF THE VERY YOUNG AGGREGATED ZOOID HAS THE SAME FORM. B, The same seen from the right side. C, The ganglion and the eye of a
. Bulletin - United States National Museum. Science. D Fig. 12.—Cyclosalpa pinnata, aggregated zooid, diagrams showing the forward rota- tion AND TRANSFORMATION IN SHAPE OF THE DORSAL EYE. FROM METCALF AND JOHNSON (1905); e, eye; gg, ganglion; r indicates in each case the same region of the eye. A, A DORSAL VIEW OF THE GANGLION AND THE EYE OF A SOLITARY SALPA. THE HORSESHOE- SHAPED EYE IS ABOVE THE GANGLION, WITH THE ENDS OF THE HORSESHOE POINTING FORWARD. THE DORSAL EYE OF THE VERY YOUNG AGGREGATED ZOOID HAS THE SAME FORM. B, The same seen from the right side. C, The ganglion and the eye of an immature aggregated zooid. The eye has now ROTATED FORWARD AND UPWARD THROUGH AN ARC OF ABOUT 90°. THAT SURFACE OF THE EYE WHICH WAS DORSAL WHEN THE EYE WAS HORIZONTAL (B) IS NOW ANTERIOR. D, The same eye and ganglion as in C, but viewed from behind. The eye is in the form OF A FLAT PLATE, THE HOLLOW OF THE HORSESHOE HAVING BECOME FHLED WITH CELLS. E, THE EYE AND GANGLION OF AN ADULT SEEN FROM THE RIGHT SIDE. THE EYE HAS SHIFTED 90° STILL FURTHER FORWARD AND IS AGAIN HORIZONTAL, BUT WITH ITS FORMER POSTERIOR PORTION ANTERIOR AND ITS FORMER DORSAL SURFACE VENTRAL. F, Dorsal view of the same ganglion and eye as in E. The eye is now split posteriorly INTO TWO LIMBS, RIGHT AND LEFT, BEING AGAIN HORSESHOE-SHAPED. downward, the two ends of the horseshoe remaining attached to the dorsal surface of the ganglion and forming the pivots upon which the eye rotates. By this rotation the originally ventral surface of the rudiment of the eye becomes first posterior then dorsal. Three other changes occur in the developing eye during the gradual completion of this forward rotation. First the space between the limbs of the horseshoe-shaped optic ridge becomes nearly filled by proliferated. 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 th
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Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
