SECTION 11. 



Hevikv* op &APLIKP Researches. 



1. Anaton ical Wofk Involving Errors of Interpretation . 

 To trace the history of a miscoriceptior) is &. task upon 

 whicli few can enter with even the least degree of enthusiasni, 

 but it is necessary for us to notice briefly here certain erro- 

 neous views which have held sway relative to the hoaiologies of 

 the parts of the selachian brain. The interbrain, and along 

 with it the midbrain and often the cerebelluiri as well, have 

 been variously interpreted by the investigators of the last 

 three decades. Wiclucho-Maclay ('70) was the first to break 

 away from the established teachings of vonEser ('?7) concerning 

 the possible homologies of the several brain-segments. Overlool 

 ing, in effect, the true interbrain entirely, since he regarded 

 it as nothing more than a longitudinal commissure, Viclucho- 

 Kcaclay identified the zwischenhirn in that segment which we 

 know as the midbrain; the cerebellum, being next in the longi- 

 tudinal series, consequently stood for his mi ttelkim; while he 

 found his hinterhim in the small inferior lole of the true 

 cerebellum. Such an interpretation appears almost inexplicable 



to us, but we must not allow oui-selves to forget that the homol- 



(6) 



