THE ORIGIN OF THE HUMAN BODY 279 



unquestionably homologous with the genuine branchial arches 

 and clefts in a fish embryo. In the latter, however, the grooves 

 become real clefts through perforation, while the arches be- 

 come the lamellae of the permanent gills, thus adapting the 

 animal to aquatic respiration. It is, accordingly, perfectly 

 legitimate to refer to these embryonic structures in the young 

 fish as gill arches and gill clefts. In man, however, the corre- 

 sponding embryonic structures develop into the oral cavity, 

 auditory meatus, ossicles of the ear, the mandible, the lower 

 lip, the tongue, the cheek, the hyoid bone, the styloid process, 

 the thymus, the thyroid and tracheal cartilages, etc. There 

 is no perforation of the grooves, and the arches develop into 

 something quite different than branchial lamellae. Hence the 

 correct name for these structures in the human embryo is 

 pharyngeal (visceral) arches and grooves, their superficial re- 

 semblance to the embryonic structures in the fish embryo 

 being no justification for calling them branchial. In short, 

 the mere fact that certain embryonic structures in the young 

 fish (homologous to the pharyngeal arches and grooves in the 

 human embryo) develop into the permanent gills of the adult 

 fish, is no more significant than the association of homology 

 with divergent preadaptations, which is of quite general occur- 

 rence among adult vertebrate types. In all such cases, we 

 have instances of fundamentally identical structures, diverted, 

 as it were, to entirely different purposes or functions {e.g. the 

 arm of a man and the flipper of a whale). Hence the argu- 

 ment drawn from embryological homology is no more cogent 

 than the argument drawn from the homologies of comparative 

 anatomy, which we have already discussed in a previous 

 chapter. The misuse of the term branchial, to prejudge mat- 

 ters in their own favor, is in keeping with the customary policy 

 of evolutionists. It is intended, naturally, to convey the 

 impression that man, in the course of his evolution, has passed 

 through a fish-like stage. At bottom, however, it is nothing 

 more than a verbal subterfuge, that need not detain us further. 

 The theory of embryological recapitulation is often applied 



