36 



CONARIO-HYPOPHYSIAL TRACT. 



pretatiou is accepted by the experienced anatomist of the 

 Arthropoda, Prof. Packard, who writes : — " In the green 

 Grasshoppers, such as the Katydes and their allies, whose ears 

 are situated in their fore legs, the ' first thoracic ganglion ' is 

 a complex one " *, such " auditory nerves " communicating 

 therewith. 



Although, physiologically, the remoter neural mass may be 

 compared with the part of the epencephalon in connexion with 

 the auditory organ, it may be too much to look for consent to 

 a corresponding homology. And, if such be denied, yet the 

 retral transfer of a sense-character beyond the gustatory one to 

 the foremost or even a remoter thoracic nerve-mass may not, 

 consequentially, affect the grounds for homologizing both the 

 so-called " supra-" and " suboesophageal " ganglia, which are 

 constant in regard to their special sense-nerves, with the parts 

 of the vertebrate brain similarly distinguished by relations to 

 nerves of special sense. 



Conclusions counter to these homologies either limit the 

 term "brain" to what is called the supraoesophageal gan- 

 gHon " in Invertebrates, or, more consistently, involve a 

 negation of the homology of any part of the central neural 

 system in Invertebrates with any part of that system in 

 Vertebrates. 



The latest neurotomist of the Arthropoda, for example, con- 

 cludes, emphatically, as follows : — " It should be remembered 

 that the word ' brain ' is applied to the compound (supra- 

 oesophageal) ganglion simply by com-tesy and as a matter of 

 convenience, as it does not correspond to the brain of a ver- 

 tebrate animal, the brain of the horse or man being composed 

 of several distinct pairs of gangha. Moreover, the brain and 

 nervous cord of the fish or man is fundamentally diff'erent, 



Packard, ' Second Eeport ' &c. p. 225. 



