106 M. Oscar von Grimm on the Agamic Ueproduction 



XIII. — On the Agamic Reproduction of a Species 0/ Chiro- 

 nomus, and its Development from the Unfecundated Egg. 

 By Oscar von Grimm. 



[Concluded from p. 45.] 



III. The Development of the Embryo in the Unfecundated 



Ovum. 



The embryonic development of Chironomus in the fertilized 

 ovum has already frequently been investigated and described 

 by various observers, such as Kolliker, Kupfer, Weismann, 

 Metschnikow*, and Melnikow; but the development from tlie 

 unfecundated ovum, as, indeed, even the ovum itself, has 

 hitherto been unknown. 



We shall see hereafter that the development of the embryo 

 from the fecundated and unfecundated ovum perfectly agrees, 

 so that we might content ourselves with describing the points 

 of divergence between our investigations and those of other 

 observers, if it were not that we intended publishing a more 

 detailed memoir on the development of the histological ele- 

 ments and organs. But, as I have already made some inves- 

 tigations in this direction, and will, as soon as possible, lay 

 the results of this work before tlie reader, I regard it as neces- 

 sary to give here a short summary of tlie course of development, 

 especially as, in some cases, I have arrived at different results 

 from Weismann, who, however, has most completely investi- 

 gated the embryology of" Chironomus. 



I must, however, remark that I shall here rarely refer to 

 authors, as I regard tliis chapter as a preface to my future 

 work. 



As we already know tliat in Chironomus the second, 

 asexually produced generation is developed from ova, we need 

 not discuss the opinion of Wagnerf and Meincrt;!: upon the 

 genesis of the Cccidomyid larvte from the fatty body of the 

 parent larva (to which, moreover, Meinert ascribes pecuHar pro- 

 perties), since the supposition of Pagenstccher§ that the larvae 

 originate independently of the f;\tty body has been proved by 



* Prof. Metschnikow's most recent investigation upon the embryology 

 of Chironomus is unfortunately only partially known to me, as it' is not 

 yet published, 



t " Beitrag zur Lehre von der Fortjiflanzung der Insectenlarven," 

 Zeitschr. fiir wiss. ZdoI. ISO;!, Bd. xiii. p. 5'2'2. 



I " Weitere Erliiutcrungen iiber die von Prof. Wa^rner beschriebene 

 Insectenlarvc,'' &c. Zeitsclir. fiir wiss. Zool. Bd. xiv. p. 3!>o, 



§ " Die ungeschlechtliche Vermehrung der Flit>genlarveu," Zeitschr. 

 fiir wiss, Zool. Bd. xiv. p, 410. 



