114 Phenomena Refuting Simple Epiyenesis 



Nevertheless some other varieties of omphalosite 

 monsters seem to show that the presence of any part 

 whatever of the vertebral axis is sufficient to permit 

 at least partial development; for instance in the cephalic 

 monsters the embryo consists generally of the head 

 alone. 77 We note however that these monsters com- 

 monly contain the anterior extremity of the spinal cord 

 which can have been only slightly differentiated in the 

 embryonic stage at which the incomplete development is 

 arrested. In some of these cephalic omphalosite mon- 

 sters, a large part of this anterior extremity of the spinal 

 cord may even have undergone a process of reabsorption 

 after the previous arrest of the partial development. 



As we shall see soon Born succeeded in producing 

 artificially a thing like these cephalic omaphalosite mon- 

 sters by grafting upon a complete tadpole a piece removed 

 from another tadpole, and consisting only of the head 

 and a small part of the elongated medulla. 



Concerning the double monsters with double sym- 

 metry, it will be worth while to repeat once more in 

 extenso the following statement of Roux, even though 

 we have reported it already, for the most part, in the 

 preceding chapter: 



"This additional fact speaks directly against the 

 achievement of development of the individual through 

 a general, reciprocal, formative cooperation of all parts 

 to form a whole; namely that in the chief class of double 

 monsters, and so in those double formations which cor- 

 respond to the law which I formulated of the double 

 symmetry of the anlagen of organs, the piece absent 

 in a symmetrically similar way from each of the two 



"Dareste : Recherches sur la prod, artif. des monstr. P. 498. 



