108 J- Leffingwell Hatch, 



in branches which divide dichotomously. Along - its entire length it gives 

 off many small and irregular, but deep and well marked branches. 



The retro-central sulcus is divided by a slight bridge of convo- 

 lution. Above this yoke it is continued for about 2 cm., it then turns 

 at right angles on itself and extends backwards and becomes confluent 

 with the intra-parietal. It is sinous throughout its entire course, and 

 gives off many short and irregular transverse branches. 



The intra-parietal fissure is not so long as that of the other 

 hemisphere, being but 10 cm. It starts in the genu of the ascending 

 parietal convolution, and following a more or less irregular course 

 backwards it crosses the post central, and terminates in a well marked 

 transverse occipital 3,5 cm. in length. 



The first spheno-temporal fissure, 10 cm. in length, is quite regular 

 in direction and extends back as far as the second occipital convo- 

 lution, where it is confluent with the sulcus occipitalis longitudinalis 

 inferior. It gives off numerous small twigs along its entire length, 

 thus aiding in the convolutionary complexity. 



The second spheno-temporal sulcus is divided in its course by an 

 insula of convoluted brain substance that is quite richly segmented. 



The two horizontal occipital fissures are regular both as to form 

 and extent. 



The external configuration of the left outer surface is much the 

 same as that of the right side. 



The mesial surface is peculiar, and has some of the same diver- 

 gences from the normal type as has the other side. 



The calloso-marginal fissure starts above the genu of the corpus 

 callosum in the gyrus fornicatus, even as on the other side, and curves 

 backwards and upwards cutting the lateral surface at its terminus for 

 a distance of 1,5 cm. It gives off one or two well marked branches 

 upwards from the anterior portion, and one downwards where it turns 

 to ascend to the top of the brain. Anterior to this the inner surface 

 of the frontal lobes is traversed by two well marked, deep, and 

 branching sulci, 4 cm. long respectively, and running parallel courses. 



The parieto-occipital is well marked, deep, and tortuous, extending 

 well over unto the external surface, where it becomes confluent with 



