. Dedication papers : scientific papers presented at the dedication of the laboratory building and plant houses, April 19-21, 1917. ls thefour coming from the original group of four form a part of the equa-12 160 BROOKLYN BOTANIC GARDEN MEMOIRS torial series, while the four coming from the peripheral four cells of theeight-celled stage (Text-fig. 2) form a new polar group of four whosecells alternate with those of the original polar group. Henfrey (56)described the sixteen-celled colony of Eudorina as consisting of twopolar groups of four and an equatorial circle of eight cells. Biitschli (83)
. Dedication papers : scientific papers presented at the dedication of the laboratory building and plant houses, April 19-21, 1917. ls thefour coming from the original group of four form a part of the equa-12 160 BROOKLYN BOTANIC GARDEN MEMOIRS torial series, while the four coming from the peripheral four cells of theeight-celled stage (Text-fig. 2) form a new polar group of four whosecells alternate with those of the original polar group. Henfrey (56)described the sixteen-celled colony of Eudorina as consisting of twopolar groups of four and an equatorial circle of eight cells. Biitschli (83) describes the sixteen-celled colony as consisting offour upper central cells, a ring of eight equatorial cells and four lowercells which alternate with the upper and gives a figure (Taf. XLV,Fig. I, i). Overtons (89) description of the arrangement of thecells in the eight-celled stage is essentially like that of Biitschli,though as Meyer notes, he ascribes the origin of the central cavityof the colony to the divergence of the cells in the four-celled stageand the subsequent hollowing out of the cells toward the center of the. I 2 Figs, i and 2. For explanation see text. colony. Neither of these authors gives any very clear account of thearrangement of the eight equatorial cells or their relationship to thepolar groups. It is not easy to obtain satisfactory photographs of these sixteen-celled stages since, as noted, they are practically spherical and thenumber of cells is so small that no characteristic groups can be ob-tained in one focus. From a study of a large number of cases andphotographs of various views I have been able to obtain data for themodel made of marbles held together with wax and shown in two viewsin text-figures i and 2. Text-figure i shows the anterior pole of the youngcolony with the four cells forming a square, as has been observed byall students of the group. The opposite posterior pole of the colonywould show a similar group of four, each cell alternatin
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectplants, bookyear1918
