[393] Even in a Protozoon (Euglena viridis), when kept alive under artificial compression, Ryder found a process of cell-division to occur which he compares to the segmenting blastoderm of a fish’s egg, and which corresponds in its essential features with that here described. Contrib. Zool. Lab. Univ. Pennsylvania, I, pp. 37–50, 1893.
[394] This, like many similar figures, is manifestly drawn under the influence of Sachs’s theoretical views, or assumptions, regarding orthogonal trajectories, coaxial circles, confocal ellipses, etc.
[395] Such preconceptions as Rauber entertained were all in a direction likely to lead him away from such phenomena as he has faithfully depicted. Rauber had no idea whatsoever of the principles by which we are guided in this discussion, nor does he introduce at all the analogy of surface-tension, or any other purely physical concept. But he was deeply under the influence of Sachs’s rule of rectangular intersection; and he was accordingly disposed to look upon the configuration represented above in Fig. [168], 6, as the most typical or most primitive.
[396] Cf. Rauber, Neue Grundlage z. K. der Zelle, Morph. Jahrb. VIII, 1883, pp. 273, 274:
“Ich betone noch, dass unter meinen Figuren diejenige gar nicht enthalten ist, welche zum Typus der Batrachierfurchung gehörig am meisten bekannt ist .... Es haben so ausgezeichnete Beobachter sie als vorhanden beschrieben, dass es mir nicht einfallen kann, sie überhaupt nicht anzuerkennen.”
[397] Roux’s experiments were performed with drops of paraffin suspended in dilute alcohol, to which a little calcium acetate was added to form a soapy pellicle over the drops and prevent them from reuniting with one another.
[398] Cf. (e.g.) Clerk Maxwell, On Reciprocal Figures, etc., Trans. R. S. E. XXVI, p. 9, 1870.
[399] See Greville, K. R., Monograph of the Genus Asterolampra, Q.J.M.S. VIII, (Trans.), pp. 102–124, 1860; cf. IBID. (n.s.), II, pp. 41–55, 1862.
[400] The same is true of the insect’s wing; but in this case I do not hazard a conjectural explanation.
[401] Ann. Mag. N. H. (2), III, p. 126, 1849.