MORPHOLOGY OF THE AVIAN BRAIN. 



( Continued. ) 

 C. H. Turner. 



Additional Remarks upon the Corpus Callosum. — Since 

 the publication of the first paper of this series, my attention 

 has been called to Professor Osborn's paper upon " The 

 Origin of the Corpus Callosum, a Contribution upon the 

 Cerebral Commissures of the Vertebi"ates."(') In that paper 

 the author makes the following instructive remarks: 



"If the brain of a duck [Anas boschas) be carefully 

 removed from the skull and the membranes uniting the 

 hemispheres cut, these bodies may be gently separated until 

 the anterior commissure comes into view^; immediately above 

 and behind this is a fine v^'hite strand of fibres, quite as 

 figured by Meckel (1816), and so distinct that one cannot 

 understand how it was overlooked by Stieda. This little 

 bundle, which represents the rudimentary corpus callosum, 

 forms a portion of the lamina terminalis, and is about one- 

 sixth the diameter of the anterior commissure. It lies some 

 distance below the foramen of Monro, and in vertical as 

 well as transverse sections its fibres are seen to pass directly 

 upwards in the thin inner wall of the lateral ventricle. So 

 far as could be ascertained, none of its fibres pass back into 

 the hippocampal region, as the commissure of the cornu 

 ammonis." 



I Morphologischer Jahrbiicher, Bd. xii, pp. 223-251, 530-543. 



