939 
aberrans and commissura superior would be closely approximated. The 
fact that the so-called commissura superior of Amphibia derives fibres 
from the caudal extremity of the cerebral hemisphere is well known, 
and has been recorded by almost all writers upon the Amphibian brain, 
so that it is unnecessary for me to adduce evidence to prove this 
matter of common knowledge. But in the light of the above recorded 
observations upon the commissura aberrans, it seems more than prob- 
able that these hemispheral fibres of the commissura superior in the 
Ichthyopsida represent the aberrant hippocampal commissure of the 
Lacertilia and Rhynchocephalia, and do not strietly belong to the habe- 
nular or superior commissure.” It appears now that this bundle is a 
fundamental component of the commissura superior in fishes and am- 
phibians and that in some reptiles and in mammals it has disappeared 
because of the great expansion of the posterior pole of the hemisphere 
and the extension caudad of the chorioidal fissure. 
In his summary KArPErs denies the existence of a commissura 
hippocampi (Psalterium) in selachians, but gives no reason for his 
view. 
With slight exceptions Doctor Kappers’ criticisms are based upon 
erroneous quotations or other misstatements; in one case he quotes 
me as confirming his work where in fact I severely criticised it; in 
another case he denounces my view because it does not agree with 
the one generally accepted; and in still another he quotes ELLIOT 
SMITH as opposed to my view, whereas the reverse is true. All these 
are of course merely errors and not intentional misrepresentations. 
I have pointed out (1910 d) certain errors of observation by Doctor 
KAPPERS because the facts compelled me to do so, and KAPPERS and 
CARPENTER (1911) have published an acknowledgment of the cor- 
rectness of my statements. The criticisms made by KAPPERS have 
been wholly unnecessary, because they rested on mistakes in reading 
my papers. Since Doctor KApprrs writes and speaks English fluently, 
he ought not to have made these mistakes. Such needless criticisms 
only waste our energies and bewilder those who are entering upon 
neurological studies. It is unfortunate also that Kapprers should ap- 
peal merely to authority in his criticisms. In the matter of the corpus 
callosum he wholly ignores my evidence and only seeks to show that 
my view is inconsistent with that adopted by prominent neurologists. 
If the facts and the interpretation had not been new why should I 
have published them ? 
We all have fresh in mind the case of Strupniéxa. He presented 
new views of forebrain morphology and was most disgracefully assailed 
