312 LAY SERMONS, ADDRESSES, AND REVIEWS, [xm, 



of the simpler kinds of Agamogenesis 1 is to be followed, 

 should be a litter, not of puppies, but of young Hyaenas. 

 For the Agamogenetic series is always, as we have seen, 

 A : B : A : B, &c; whereas, for the production of a new 

 species, the series must be A : B : B : B, &c. The pro- 

 duction of new species, or genera, is the extreme perma- 

 nent divergence from the primitive stock. All known 

 Agamogenetic processes, on the other hand, end in a 

 complete return to the primitive stock. How then is 

 the production of new species to be rendered intelligible 

 by the analogy of Agamogenesis ? 



The other alternative put by Professor Kolliker — the 

 passage of fecundated ova in the course of their develop- 

 ment into higher forms — would, if it occurred, be merely 

 an extreme case of variation in the Darwinian sense, 

 greater in degree than, but perfectly similar in kind to, 

 that which occurred when the well-known Ancon Earn 

 was developed from an ordinary Ewe's ovum. Indeed 

 we have always thought that Mr. Darwin has unneces- 

 sarily hampered himself by adhering so strictly to his 

 favourite "Natura non facit saltum." We greatly 

 suspect that she does make considerable jumps in 

 the way of variation now and then, and that these 

 saltations give rise to some of the gaps which appear 

 to exist in the series of known forms. 



Strongly and freely as we have ventured to disagree 



1 If, on the contrary, we follow the analogy of the more complex forms oi 

 Agamogenesis, such as that exhibited by some Trematoda and by the Aphides, 

 the Hyama must produce, asexually, a brood of asexual Dogs, from which 

 other sexless Dogs must proceed. At the end of a certain number of terms 

 of the series, the Dogs would acquire sexes and generate young ; but these 

 yomig would be, not Dogs, but Hysenas. In fact, we have demonstrated, in 

 Agamogenetic pha?nomena,that inevitable recurrence to the original type, which 

 is asserted to be true of variations in general, by Mr. Darwin's opponents ; 

 and which, if the assertion could be changed into a demonstration, would, in 

 fact, be fatal to his hypothesis. 



