126 CHAPTERS ON EVOLUTION. 



The old view of Goethe in its general acceptation may be held 

 to be strengthened by later research. The recent view of Owen 

 has been modified in some quarters to the effect that no less 

 than twenty segments or vertebrae compose the skulls of higher 

 animals. But the fundamental conception of the newer view seeks 

 to recognise in the vertebrae of the skull, not so much an exact 

 correspondence with the fully developed vertebra as with the primi- 

 tive type of the latter structure. Professor W. K. Parker, whose 

 labours in this field are so well known, for example, declares that 

 there exists " no definite evidence of segmentation in the history of 

 the highly perfected " gristle-skull of such a primitive and ancient 

 stock of fishes as the sharks, dog-fishes, and rays ; and he further 

 remarks, that " we do not conceive of the skull as being composed 

 of a number of coalesced vertebrae; not having perceived any 

 indications of any process of coalescence in the embryo, and being 

 unaware of any evidence of the past occurrence of such a transforma- 

 tion in ancient times." It need not be added that the likeness of the 

 skull "segments" of modern anatomists to the complicated "vertebrae" 

 of which the earlier workers conceived the skull to be composed, is by 

 no means included as a part of the views of later research. The " seg- 

 ments" of the skull, in other words, are not necessarily the elaborate 

 " vertebrae " we now behold in the spine. Indeed, Professor Parker 

 is very exact in insisting upon the fact that in fishes and amphibians 

 by which latter name we designate the frogs and their relations there 

 is but one well-defined bony segment to be descried. " And," adds 

 this author, " in these forms there are no good grounds for assigning 

 to the cranial bones special names indicating a correspondence to 

 particular parts of vertebras." In the skull of quadrupeds there 

 are but three well-defined segments, according to Professor Parker ; 

 but it does not follow that they constitute three cranial (or skull) 

 " vertebrae "; and very decisive are his succeeding words : " We cannot 

 admit that our investigations give any reason for describing the skull 

 as constructed by the modification of a series of vertebrae, still less for 

 viewing it as directly made up of a number of cranial vertebrae." But 

 our author does not leave us in doubt as to the difference which his 

 views entail between former ideas of the composition of the skull 

 and the results of recent research. "We find," says Mr. Parker, 

 "that every form of skull that has been investigated, every stage 

 in development, contributes to one idea, which becomes simpler, 

 more intelligible, more harmonious, by the pursuit of a right process 

 of investigation. There is a unity of structure in the skeleton of 

 the head, a fundamental formal unity, which may always be perceived ; 

 and an adaptability to the most varied conditions of life in water, on 

 land, in air, which becomes more, and not less, astonishing as know- 

 ledge slowly and surely increases." 



