. Lessons in botany. Botany. Fig. 144. Fig. 145. Section of antheridia showing sperm cells, and spermato- _ Different views of spermatozoids; zoids in the one at the right. in a quiet condition ; in motion (Adiantum concinnum). 281. Antheridia.—If we search among the rhizoids we see small rounded elevations as shown in figure 139 scattered over this portion of the prothallium. These are the antheridia. If the prothallia have not been watered for a day or so, we may- have an opportunity of seeing the spermatozoids coming out of the antheridium, for when the prothallia are freshly placed in wate
. Lessons in botany. Botany. Fig. 144. Fig. 145. Section of antheridia showing sperm cells, and spermato- _ Different views of spermatozoids; zoids in the one at the right. in a quiet condition ; in motion (Adiantum concinnum). 281. Antheridia.—If we search among the rhizoids we see small rounded elevations as shown in figure 139 scattered over this portion of the prothallium. These are the antheridia. If the prothallia have not been watered for a day or so, we may- have an opportunity of seeing the spermatozoids coming out of the antheridium, for when the prothallia are freshly placed in water the cells of the antheri- dium absorb water. This presses on the contents of the antheri- dium and bursts the cap cell if the antheridium is ripe, and all the spermatozoids are shot out. We can see here that each one is shaped like a screw, with the coils at first closed. But as the F's; h6' . Archegonium of fern. Large cell in SDermatOZOid begins tO move th<= venter is the egg, next is the ventral r o canal cell, and in the canal of the neck this Coil Opens Somewhat and are two nuclei of the canal cell. by the vibration of the long cilia which are on the smaller end it whirls away. In such preparations one may often see them spinning around for a long while, and it is only when they gradually come to rest that one can make out their 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 Atkinson, George Francis, 1854-1918. New York, H. Holt and company
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