70 JOURNAL OF COMPARATIVE NEUROLOGY. 
widest possible distribution among investigators, with all the 
prestige of GEGENBAUR’s authority behind them. GEGENBAUR 
has rectified the mistake in the latest form assumed by his text- 
book (’98), but it probably will be many years before the mis- 
chief is fully undone. 
StiepA ('73b) devoted himself to a correction of the erro- 
neous conceptions promulgated by Micrucno-Macray and 
GrecEenBaur. After carefully considering the subject-matter at 
issue, he embodied his conclusions in a table in which the 
homologies of the several brain-segments are properly set forth. 
The work of this author had the effect, at least, of directing 
the attention of anatomists once more to the fact that the 
homologies of the fish-brain were really in question, resulting, 
ultimately, in the true interpretation prevailing at the present 
time. 
Rouon (’77), aithough writing several years after the pub- 
lication of Strepa’s paper, did not fully accept the work of that 
author, but took a position almost between the errors of 
MiciucHo-Mactay on the one hand, and the truth on the other. 
While giving the cerebellum its proper recognition as a brain- 
segment, he apparently annexed his vegzo ventriculo tert to the 
forebrain, thus leaving the midbrain standing for two whole 
segments. His Zw7schenhirn, therefore, embraced the dorsal 
portion of the optic lobes above, and the hypothalamus below; 
while he located the Mttelhiwn between and behind these two 
divisions of his Zwischenhirn. Such an interpretation was cer- 
tainly remarkable for the ingenuity with which a place was 
found where an error might be lodged, but it was almost, if not 
quite, equaled by the general homologies drawn by Frirscu 
(78), who took the whole midbrain for a secondary Vorderharn. 
These several errors, curious as some of them certainly 
are, might have little more than a passing interest for us to-day, 
were it not that they continue to reappear at intervals, tinging 
the work of those making claims to a certain degree of author- 
itative treatment. As an instance of this kind, it may be noted 
that one of our most recent treatises on comparative anatomy 
contains a figure of the selachian brain with the cerebellum 
