174 A MANUAL OF ANATOMY. 



(The above formation of the fifth ventricle is taken from 

 Minot's " Embryology," and is undoubtedly the correct 

 view, though contrary to the usual teachings.) 



Within the lamina terminalis, below the septum lucidum, 

 and in front of the anterior part of the fornix, is developed 



Diag. 16. MEDIAN VERTICAL ANTEROPOSTERIOR SECTION, at same stage as pre- 

 ceding diagram, to illustrate the development of the lamina terminalis into the corpus 

 callosum, septum lucidum, fornix, and the anterior commissure. (/. S. H.) i, Corpus 

 callosum. 2, Septum lucidum. 3, Anterior commissure. 4, Fornix. 5, Optic chiasm. 

 Remainder of parts as in preceding diagram. 



a well-defined band of fibres which serves to connect the 

 opposite forebrains and is called the anterior commissure. 



The flexures of the cerebral vesicles take place early 

 and consist of a " head-bend " at the midbrain, and later a 

 "neck-bend" at the junction of medulla and spinal cord. 



