190 A MANUAL OF ANATOMY. 



parieto-occipital, calcarine, hippocampal or dentate, and the 

 collateral. 



The parieto-occipital fissure deeply grooves the inner 

 surface of the cerebrum in a direction downward and 

 forward, starting at the junction of the posterior one-fifth 

 with the anterior two-fifths of the margin (inner) of the 

 hemisphere, and terminating opposite a point directly below 

 the splenium of the corpus callosum. 



The calcarine fissure begins in the posterior part of 

 the occipital lobe and passes directly forward to merge 

 into the parieto-occipital fissure at its middle point. 



The corresponding elevation within the lateral ventricle 

 produced by the calcarine fissure is called the calcar, or 

 hippocampus minor. 



The Hippocampal or Dentate Fissure. Figs. 27, 28. 



This is a groove which begins just below the hinder end 

 of the corpus callosum and runs forward in the internal 

 margin of the temporal lobe. The elevation which it pro- 

 duces in the middle horn of the lateral ventricle is the 

 hippocampus major. By separating the lips of the fissure 

 the floor is seen to have a transversely striated appearance, 

 hence the name of dentate fissure. 



The Collateral Fissure. Fig. 28. 



This fissure extends anteroposteriorly from the temporal 

 into the occipital lobes. 



The raised portion of brain matter produced by this 

 fissure in the floor of the (posterior and descending horns 

 of the) lateral ventricle is called the eminentia collateralis. 



The Callosomarg-inal Fissure. Figs. 27, 38. 



This is a well-marked sulcus which begins beneath the 

 anterior extremity of the corpus callosum, turns backward, 

 conforming to the curve of this structure until over its 



