Insects, 4501 



of all true individuality is maintained ; and the axiom of Harvey, 

 omne vivum ex ovo, stands as golden in physiology. The buds may 

 put on the dress and the forms of the ovum, but these resemblances 

 are extrinsic, and in fact only an inheritance from their great prede- 

 cessor. 



These phenomena, thus interpreted, furnish an excellent key to 

 many others which have long been regarded as anomalous in the his- 

 tory of development. 



I refer here to the so-called hybernating eggs {Winter eier) which 

 are found in many invertebrates. These I have not seen, but they 

 have been carefully described by several very trustworthy observers. 

 These so-called eggs consist of oval masses or cells invested with a 

 capsule, but in which no germinative vesicle and dot have ever been 

 seen. Structurally, therefore, they do not resemble eggs, and it is 

 from their form and ulterior development only that they have received 

 this name. Moreover, they sustain none of the usual relations of eggs 

 to the sexual organs, and, as far as I am aware, no one has witnessed 

 their development in the ovaries. These bodies have been observed 

 in Hydatina and Notommata among the Infusoria; in Lacinularia 

 among the Rotatoria ; and in Daphnia among the Crustacea. In all 

 these instances they hatch without the aid of the male, the existence 

 of which sex was once doubted from its unfrequent appearance. 



Now I regard these hybernating eggs as merely egg-like buds ex- 

 actly corresponding to the germs of the viviparous Aphides. In other 

 words, there are in the animals I have just mentioned certain indivi- 

 duals which reproduce by buds which are developed under rather 

 anomalous conditions ; and I will add, in conclusion, that I suspect 

 that this gemmiparous mode of reproduction will be found to be far 

 from uncommon among most of the Invertebrata, when our researches 

 into the history of their development shall have been more widely ex- 

 tended. 



P.S. Since the publication of this paper, I have enjoyed the oppor- 

 tunity of making this series of investigations more complete, by an 

 examination of the terminal or last brood, which appears at the end 

 of autumn. 



This terminal brood has hitherto been considered, as far as I am 

 aware, to be composed exclusively of males and females, or, in other 

 words, of perfect insects of both sexes. I was surprised, therefore, 

 on examining the internal organs of the non-winged individuals, to 

 find that many of these last were not females proper, but simply the 

 XIT. 2 z 



