234 



würde ich darin einen wesentlichen Fortschritt sehen. Das Unter- 

 nehmen kann ja jederzeit weiter ausgedehnt werden, und da dann eine 

 Norm der Darstellung gegeben ist, könnten spätere Autoren schließlich 

 ja auch unabhängig im gleichen Sinne vorgehen. 



Nachdruck verboten. 



Oll the Phenomena of Reproduction in Animals and Plants, on 

 antithetic Alternation of Grenerations , and on the Conjugation 



of the Infusoria. 



By J. Beaed, D. So., University Lecturer on Comparative Embryology^ 



University of Edinburgh. 



With five Figures. 



On Antithetic Alternation of Generations. 



By J. Beabd. 



A recent number of the "Annals of Botany" contains Stras- 

 burger's conclusions on "the periodic reduction of the chromosomes 

 in living organisms" ^). The paper, though largely based on facts of 

 plant-morphology, is not without its special significance to the zoologist 

 and animal morphologist. In the zoological world Strasburger's 

 statements appear to have created more unrest than satisfaction, and 

 they have already led to an elaborate and somewhat ingenious criti- 

 cism ^) from the pen of V. Haecker ^). And naturally so, even though 

 it should subsequently become apparent that in this, as in so many 

 other cases, Strasburger was mainly in the right in his contentions 

 so far as these relate to plants. How could it be otherwise? Is not 

 the zoologist as such concerned with processes in which an antithetic 

 alternation of generations is only conspicuous by its absence? How 

 then shall he of all men accept an explanation of the meaning and 

 nature of a process in plants, when to what is, to all appearance, the 

 corresponding phenomenon in animal reproduction the interpretation 

 offered would seem totally incapable of application? 



1) Ann. of Botany, Vol. VIII, 1894, p. 281—316. 



2) Y. Haeckek, The Reduction of the Chromosomes in the Sexual 

 Cells. Ann. of Botany, Vol. IX, 1895, p. 95 — 101. 



3) Haecker's objections are certainly weighty ones, and are only ren 

 dered in some respects nugatory by the acceptance of a very difi'eren- 

 view of the nature of animal development from that hitherto adoptedt. 



