SECT. 2] 



AND WEIGHT 



507 



for Strongylocentrotus lividus, from which Kanitz calculated temperature 

 coefficients agreeing with Peter's. Bialascewicz confirmed the work 

 of Hertwig on the amphibian embryo, but obtained a lower average 

 temperature coefficient, namely, 2-40. For the early development of 

 Strongylocentrotus lividus Loeb found in 1908 an average Qj^q of 2-86, 

 which varied thus with temperature: 



For the early development of Ascaris megalocephalus, Faure-Fremiet 

 found Ohio's as follows : 



0-16 6-25 



16-23 393 



23-32 I 82 



and for that o^ Sabellaria alveolata: 



Ephrussi (in 1926) studied the different phases of mitosis in sea- 

 urchin and nematode eggs, allotting to each a characteristic tempera- 

 ture coefficient. Thus he obtained the following figures, working 

 always between 18 and 25° C. and calculating for each period 

 separately, not in a cumulative fashion from zero hour. 



Table 70. n 



A (from zero hour to disappearance of nuclear membrane, zero being 

 copulation of pronuclei in S. lividus and laying in A. megalocephala 



B (from disappearance of nuclear membrane to the first appearance 

 of the equatorial plate) 



A plus B, i.e. the whole of the prophase 



C (duration of the equatorial plate stage) 



Z) (duration of the whole of the anaphase) 



E (reconstitution of nuclei after mitosis) 



A plus B plus C plus D plus E, i.e. the whole mitotic process 



B plus C plus D plus E, i.e. from disappearance of nuclear membrane 

 to reconstitution of nuclei after mitosis 



I •41 



1-45 



