PHYSIOLOGICAL SRR1 1 



There is a well-formed corpus callosum with a particularly 

 well-developed genii (fig. 72). 



The hippocampal formation conforms to the usual 

 Eutherian type. 



The rhinal fissure however presents peculiar features. 

 It consists of a deep, long horizontal anterior rhinal 

 extending two-thirds of the length of the hemisphere ami 

 ending blindly in a triangular depression posteriorly. 

 There is a shallow posterior rhinal fissure which is not 

 joined to the anterior rhinal on the right hemisphere, and 

 is connected to it only by a very shallow furrow on the 

 left (fig. 73). In the region of approximation of these 

 two fissures there is a deep triangular depression, in which 



Fig. 73. (x.) 

 . . , 



the anterior rhinal fissure terminates. Holl has shown thai 

 this depression is formed by a sulcus which he calls the 

 ectosylvian. 



There is a typical presylvian (orbital) sulcus which is 

 placed very far forward and pursues a very oblique, almost 

 horizontal, course, to join Holl's ectosylvian sulcus. The 

 upper lip of the latter sulcus is operenlar and meets the lip 

 of the rhinal fissure. 



The suprasylvian sulcus is deep and oblique, and is often 

 -implemented by a second arcuate element. This ,-eeond 

 element may be independent (see right hemisphere of this 

 brain), or it may be fused to tho true snprasylvian to form 

 a triradiate sulcus (as in the left hemisphere of this ;m d the 

 right hemisphere of the next specimen). 



Two sagittal sulci, the longer one placed behind the 

 shorter, extend the whole length of the hemisphere parallel 

 to the interbemitpheral <-]i>\'\. The anterior sulcns probably 



