HARPER: BINARY FISSION AND SURFACE TENSION 165 



of the male gametes as they form, is not clear, though it is generally 

 agreed that the cell arrangement in the bundle of male gametes is 

 homologous with that of the young vegetative colony. 



Klein ('97) describes colonies of antherozoids in the form of hollow 

 spheres. Stein ('78) had also observed them. Chodat ('02) reports 

 plate-shaped individuals of Pandorina. These cases indicate how 

 closely the plate-shaped and the spherical colonies are related physi- 

 cally. The globular antherozoid bundles in Volvox may well be 

 regarded as tending toward the vegetative and away from the sexual 

 condition. That such changes should involve changes in surface 

 tension and adhesion is quite conceivable, as the elongation of the 

 antherozoid cell body must of course be a factor in determining the 

 form of colony. The further study of the formation of these abnormal 

 male colonies, especially, should throw light on the whole series of 

 morphogenetic problems here involved. The facts as known are 

 certainly quite in harmony with the view that such presumably easily 

 influenced factors as adhesion and surface tension, combined with the 

 more fundamental and ever-present incompatibility between the 

 principles of binary fission and least surfaces, may be of determining 

 significance in the transition from the plate-shaped to the three- 

 dimensional globular form of colony with all its evolutionary sig- 

 nificance. 



INDEX OF LITERATURE 



Cohn, F. Untersuchungen iieber die Entwickelungsgeschichte der mikroskop. 

 Algen u. Pilze. Nova acta Leop.-Carol. 24 (i): loi. 1854. 



Henfrey, A, Notes on Some Fresh-water Confervoid Algae. Trans. Mic. Soc. 

 London, N. S., IV, p. 49. 1856. 



Hofmeister. Die Lehre von der Pflanzenzelle. Leipzig. 1867. 



Braun, Al. Bemerkungen zu Cohn's Schrift ueber Volvox. Sitz.-Ber. d. Ges. 

 naturf. Freunde zu Berlin, Bot. Z. 190. 1875. 



Braun, Al. Ueber einige Volvocineen. Sitz.-Ber. d. Ges. naturf. Freunde, Bot. Z. 

 189. 1875. 



Cohn, F. Die Entwickelungsgeschichte der Gattung Volvo.x. Beitr. z. Biologie 

 der Pflanzen 3: 93. 1875. 



Goroschankin. Die Genesis bei den Palmellaceen. Versuch einer vergl. Morpho- 

 logic der Volvocineae. Nachr. d. Kais. Ges. f. Naturw. usw. Moskau, 16. 



1875- 

 Sachs, J. Ueber die anordnung der Zellen im jungsten Pflanzenteilen. 1878. 

 Stein, Fr. V. Organismus der Infusionstiere. 3: i. 1878. 

 Kirchner. Ueber die Entwickelungsgeschichte von Volvox minor. Cohn's Beitrage 



3: 95. 1879. 

 Goebel, K. Grundziige der Systemalik uml spuziellen Ptlanzcninorphologie. 1882. 

 Falkenberg. Die Algen. Schcnk's Handbuch, p. 284. 1882. 

 B'iitschli. Protozoa. Bronn's Klasscn u. Ordn. d. Tierreichs. i. 1883. 

 Klebs, G. Organization ciniger Flagellatengruppen und ihre Beziehungen zu Algen 



und Infusorien. Arb. d. bot. Inst. Tubingen i: 339. 1883. 



