274 LESSONS FKOM NATURE. [CHAP. VIII. 



known plate of Professor Owen s book on the Archetype of 

 the Vertebrate Skeleton, is striking enough. 



It is none the less true that there are profound differences 

 between the two conceptions. According to the recently put 

 forth view, the skull of the higher vertebrates is really made 

 up of something less than twenty segments, each of which 

 has a morphological value equivalent to a spinal vertebra 

 with its annexed parts. Again, the recent conception does 

 not repose upon a speculative basis, but presents us with a 

 concrete type instead of an abstract ideal. And yet even 

 the concrete Amphioxus must be idealised to serve as the 

 type of vertebrate structure, since though its body is seg 

 mented as a whole, the central part of the spinal column is 

 not segmented, but presents, like the embryos of the higher 

 animals, a continuous chorda dorsalis. 



The conception of cranial vertebrae, then, like conceptions 

 of serial, bilateral, special, and general homology, 

 The answer. ^ f orm i ng p ar ts of &quot; Philosophical Anatomy,&quot; are 

 subjective apprehensions of relations which have an objective 

 existence in nature. Such conceptions are similar to our 

 conceptions of &quot; types,&quot; the very name of which is dis 

 tasteful to so many. It is true that types, as types, are not 

 real objective entities. But though, as types, they are ideal, 

 they have none the less a basis in reality. The fact that they 

 have no complete concrete being as types, is no more a reason 

 for refusing to recognise their existence than is the non-exist 

 ence objectively of species, as species, a reason for refusing to 

 recognise the individual realisation of a species or to make use 

 of zoological and botanical specific names. The acceptance 

 of the theory of evolution forms no bar to the reception of 

 that view which represents all organic forms as having been 

 created according to certain fixed ideal types. The two beliefs, 

 far from being reciprocally exclusive, can and do co-exist in 

 perfect harmony in one and the same individual mind. 



But have the conceptions of philosophical anatomy any 

 other existence besides that subjective existence in the human 

 mind, and that objective foundation in the natural world, 



