276 Professor Owen on Metamorphosis and Metagenesis. 



repeats the process ; and it may be again repeated in the 

 same geometrical ratio until a number which figures only 

 can indicate and language almost fails to express, is the 

 result. The Aphides produced by this internal gemmation, 

 are as countless as the leaves of a tree, to which they are so 

 closely analogous. 



It generally happens that the metamorphosis which has 

 been described as occurring after the seventh or eleventh 

 generation takes place much earlier in the case of some of 

 the thousands of individuals so propagated ; just as a leaf- 

 bud near the root may develope a leaf-stem and a flower with 

 much fewer antecedent generations of leaves from buds than 

 have preceded the formation of the flower at the summit of 

 the plant ; or just as one of the lower and earlier formed 

 digestive polypes may push out a bud to be transformed into 

 a procreative and locomotive polype. The same analogy is 

 closely maintained throughout. 



The wingless larval Aphides are not very locomotive ; they 

 might have been attached to one another by continuity of 

 integument, and each have been fixed to suck the juices from 

 the part of the plant where it was brought forth. The stem 

 of the rose might have been incrusted with a chain of such 

 connected larvse as we see the stem of a fucus incrusted with 

 a chain of connected polypes, and only the last developed 

 winged males and oviparous females might have been set 

 free. The connecting medium might even have been per- 

 mitted a common current of nutriment contributed to by 

 each individual to circulate through the whole compound 

 body. But how little of anything essential to the animal 

 would be aff'ected by cutting through this hypothetical connect- 

 ing and vascular integument and setting each individual free ! 

 If we perform this operation on the compound zoophyte, the 

 detached polype may live and continue its gemmiparous 

 reproduction. This is more certainly and constantly the 

 result in detaching one of the monadiform individuals which 

 assists in composing the seeming individual whole called 

 " Volvox globator ; " and so likewise with the leaf-bud. And 

 this liberation Nature has actually performed for us in the 

 case of the Aphis, and she thereby plainly teaches us the true 



