448 Dr. L. Radlkofer on Fecundation in the Vegetable Kingdom, 



whether the contents of each of the conjugating cells are con- 

 verted into separate cells before copulation^ by the formation of 

 an investing membrane, and whether this opinion may not have 

 originated perhaps merely from cases of monstrous spore-forma- 

 tion, similar to those represented by Cohn, fig. 10. pi. 17, in 

 the ' Nova Acta Acad. C. L. C vol. xxiv., — the observations of 

 Areschoug have assured us that the resting-spore originates only 

 by the union of two masses of plasma developed and nourished in 

 separate organs. We can no longer hesitate to consider one of 

 them as the analogue of the male semen, the other as the ana- 

 logue of the ovum*. We meet here with a second example of 

 fecundation ivithout definitely formed spermatic elements. At the 

 same time we see here unequivocally, the fecundating substance 

 take a direct share in the constitution of the germ (the resting- 

 spore). This simplest case of the fecundating process is that 

 in which its essential nature is most clearly announced. 



We also obtain here some important indications as to the 

 proper signification of the process of fecundation. For when we 

 behold in the Desmidiacese that from the conjugation of two 

 individuals, which are only capable of this act once, in each in- 

 stance only one spore is produced, and therefore find the process 

 of fecundation here a process of reduction instead of a process of 

 multiplication, we are necessarily led to the conclusion that we 

 must not conceive fecundation to be essentially a means for the 

 multiplication of individuals, that is, for the maintenance of the 

 existence of the species, even in those cases where nature has 

 assigned this part to it on account of the complicated organi- 

 zation of a being having rendered impossible a multiplication 

 through direct individualization of one of its parts — that is, 

 through asexual propagation. When we see, on the other hand, 

 how, in asexual propagation, the progeny depart more and more 

 from the type of the first, sexual stock (the ancestors), while this 

 type is restored by sexual reproduction, we can hardly be in 

 error if we regard the fecundating process as essentially the 

 means which nature employs to maintain the species in its full 

 integrity, corresponding to the original plan of structure. This 

 object (if, for convenience, we may be allowed so to express it) 

 seems to be so important to it, that in certain cases an effort is 

 made to attain it even at the cost of diminishing the number of 

 individuals. Perhaps this condition is most strikingly exempli- 

 fied in the behaviour of Palmoglcea, in which we see even two 

 individuals, not merely their parts, become blended together, in 



* We have already become acquainted with a spore-formation through 

 conjugation in the Fungi also. Unless the position of the plant in ques- 

 tion among the Fungi be doubtful, this would be the first case of a sexual 

 reproduction in the class. 



