. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. O O '° 168 1295 MO 85 TEMPERATURE 77 MI2 14 16 18 STAGE 20 Fir,. 2 (left). Krogh's (1914) data for Rana Inityrhina showing"the relation at different temperatures of stage to time from Ordinate represents the logarithm of time from fertilization (for cleavages in minutes, for later stages in hours) ; abscissa, temperature in °C. The symbols over the curves represent first cleavage, and 7 mm. length, branched gills, external gills, and medullary groove closure. For the sake of rea
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. O O '° 168 1295 MO 85 TEMPERATURE 77 MI2 14 16 18 STAGE 20 Fir,. 2 (left). Krogh's (1914) data for Rana Inityrhina showing"the relation at different temperatures of stage to time from Ordinate represents the logarithm of time from fertilization (for cleavages in minutes, for later stages in hours) ; abscissa, temperature in °C. The symbols over the curves represent first cleavage, and 7 mm. length, branched gills, external gills, and medullary groove closure. For the sake of ready comparison, the data for the formation of external gills are plotted as a straight line by the arbitrary distortion of the tem- perature axis. The latter are used as a base for the data for other stages. FIG. 3 (right). Moore's (1939) data for Rana pipiens showing the relation, at different temperatures, of stages between gastrulation and gill circulation to time from first cleavage. Ordinate represents time from first cleavage in hours; abscissa, stage of development (Pollister and Moore, 1937). For the sake of ready comparison the data for ° are plotted as a straight line by the arbitrary distor- tion of the stage axis. The latter are used as a base for the data from other temperatures. later development are all parallel. For example, in Fig. 3 Moore's data for Rana pipiens are presented. These supplement the data in 3 It should be pointed out that the similarity in temperature relation among these stages does not necessarily imply that each step in the formation of a given stage has the same temperature relation. There may be differences of short dura- tion which might be in opposite directions and cancel one another. At any rate, if there are such differences, they are not additive, for the overall sort of examination made does not reveal them. The stages in between gastrulation and stage 20 are not clear-cut enough to obtain easily sufficiently accurate determina
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
