No. I.] THE VERTEBRATE EAR. 5 



accepted by all vertebrate morphologists, at least unchallenged, 

 for the very good reason that there was no basis on which to 

 make any adequate argument to the contrary. 



Below I quote Hasse's words expressing his convictions after 

 many years' work in this field of vertebrate morphology, which 

 will apply to his views as advocated by Hertwig in the latter's 

 Lebrbiich d. Vergl. Embryologie, Ed. 1888. " Bei immer welter 

 in der Thierreihe ausgedehnten Unutersuchungen ist es begrief- 

 lich, dass manche Ansicht, die man bei den ersten Schritten 

 auf diesem schwierigen Gebiete gewonnen und als fundamental 

 hingestellt, im weiteren Verlaufe der Beobachtungen nicht un- 

 bedeutende Modificationen erfahrt, dass das, was das eine Mai 

 wichtig erschien, spater als Beiwerk sich herausstellt." 



It can now be shown that the vertebrate ear is derived from 

 a superficial structure not known to exist among invertebrates, 

 and it consequently follows that the auditory organs of the two 

 groups cannot be genetically related in any more direct or 

 important sense than that involved in the common descent of 

 all animals from some simpler parental form, — a proposition 

 which no one at the present day would for a moment think 

 sufficient ground for establishing the genetic connection of the 

 organs in the two groups. I shall now endeavor to place in 

 clear light the indisputable claims of the canal organ as parent 

 form of the vertebrate internal ear. I do so, however, in the 

 same spirit in which Hasse offered his solution of the problem 

 of the phylogeny of the auditory organ, expressing my feelings 

 in his words. " Gliicklich ware ich, sollte es einem anderen 

 Forscher auf Grund ebenso eingehender Forschung gelingen, 

 die Haltbarkeit oder Unhaltbarkeit meiner folgenden Ausein- 

 andersetung nachzuweisen, es hatte dann doch ein kleines Kap- 

 itel der Vergleichenden Anatomic der Wirbelthiere einen gewis- 

 sen Abschluss erreicht, der, um der Morphologic des Menschen 

 ein festes, wissenschaftliches Fundament zu geben, den meisten 

 iibrigen dringend zu wiinschen ware." While I believe that we 

 now possess the essentials of the whole history of the vertebrate 

 ear, I am none the less conscious of the extremely slow growth 

 our knowledge of this subject has had, and of its fragmentary 

 state in many details. I should do myself an injustice did I 

 not state that I am cognizant of the fact that some old, and 



