THE GASTllAUA-THEORY, ETC. 243 



alliance, whereby the ground is got ready for a monophyletic 

 system. Through these cognisable connections the hard 

 and fast conception of the stems, as derived from the earlier 

 doctrines of type, must become significantly more pliant, for 

 we find the relationship of the types to one another in the 

 manner as we meet the subdivisions within the types, i. e., in 

 genealogical partition (1. c, p. 77). 



With this concejDtion the type-theory of Baer and Cuvier 

 is at once destroyed, as well in the extent as in the content 

 of the idea of type. The type has consequently completely 

 lost its earlier significance, and so far as it is a category of 

 the system, possesses no other philosophical significance than 

 the lowest category of class, order, genus, species, and so 

 forth, it is now only relatively (through its height), not 

 absolutely, distinguished from the latter ; so even Gegenbaur, 

 from the line of comparative anatomy, has attained to the 

 same position in respect to the type-theory as that to which 

 the way of comparative ontogenesis has carried us. The 

 type-theory has an extraordinary merit for zoology, and, 

 as the highest principle of the classification of the animal 

 kingdom, had efiected on all sides an uncommonly fruitful 

 and stimulating work. Its efficaciousness is, however, to be 

 looked on now as ended. The consistent application and 

 carrying out of the theory of descent which we have com- 

 pared with it is no longer sufficient ; in its place must now 

 come the phylogenetic classification of the animal kingdom, the 

 essential basis of which is formed by our Gastraea-theory. 



APPENDIX. — Synoptic Phylogenetic Tables. 



For a hasty survey of the general results which appear to 

 develop themselves from the Gastraea-theory, the following 

 four phylogenetic tables are appended. To avoid the many 

 misinterpretations which I have put on the similar tables and 

 stem-structures in my ' General Morphology ' and in my 

 * Natural Creation,' as also in my ' Monograph of Calcareous 

 Sponges,' I may here expressly mention that these claim 

 absolutely no dogmatic currency, that they are merely essays 

 to give a clear insight, with the help of the Gastraea-theory, 

 into the important relationships of the ontogenetic and the 

 phylogenetic development of animals and their primary system 

 of organs. Should the attempt not be agreed with, let some 

 better positive be put in its place, but let the objector not rest 

 contented, as too often happens, with a mere negative rejec- 

 tion. At all events, the herein proposed system of animals 

 coincide closer to the important facts of developmental history 

 than all other hitherto attempted experiments of classification. 



