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accordingly being formed by what is, in its relations to the organs, the fifth instead of the 

 fourtli tube of tbe line. Furthermore, there is no primary tube between the first and second 

 frontal organs, and it is apparently the terminal tube of the line, instead of the penultimate tube, 

 that anastomoses with the main infraorbital canal. 



The preoperculo-mandibular canal anastomoses by its dorsal end with the main infraorbital 

 as that canal traverses the pterotic. The canal traverses, as usual, the preopercular, articular and 

 dentary, the former bone lodging six sense organs, the articular lodging one organ, and the dentary 

 two organs; all innervated by the mandibularis externus facialis. 



