LITERARY NOTICES. 



Fissures of the Cerebrnm. 



Dr. D. J. Cunningham,! in the memoirs of the Irish Academy 

 of Science bearing his name, gives an extended account of the com- 

 parative development of the surface anatomy of the cerebral hemis- 

 pheres. We condense from this work the following statements. 



I. Complete fissures ["Total falten".] The transitory fissures 

 which appear in an early period of the development of the hemis- 

 pheres are distinguished by the fact that they are a result of a series 

 of deep infoldings of the thin cerebral wall and form shelf-like pro 

 jections into the ventricles. 



Under normal conditio'. s none of the fissures which appear 

 on the lateral aspects of the hemispheres persist in the adult though, 

 in the ape, two, at least, are persistent. Upon the mesal aspect, on 

 the contrary, the choroid, a portion of the arcuate, and sometimes 

 the parieto-occipital with part of the calcarine fissures persist. The 

 choroid and arcuate appear as early as the fifth week. The choroid 

 fissure occupies the lowest limit of the mesal wall, reaching the 

 porta, cephalad, and extending caudad nearly to the extremity of the 

 temporal lobe. Though not at first occupied by blood vessels and, 

 therefore, not formed by them, its walls do not develop into nervous 

 tissue but remain epithelial and are occupied by this preplexus. The 

 fissura arcuata \Ammonsfurche of Mihalkovics] makes its appearance 

 on the mesal face of the hemisphere at a higher level than the choroid 

 fissure and while it extends, like the preceding, into the temporal 

 lobe it also passes cephalad into the frontal region. That portion of 

 the hemisphere lying between the two fissures mentioned is termed 

 the arcus marginalts, in connection with which are formed the 

 callosum, the gyrus dentatus and the fornix. 



The caudal part of the fissura arcuata is retained in adults as 

 the hippocampal fissure and gives rise to the elevation in the floor of 

 the descending cornu known as the hippocampus major. 



^Contribution to the Surface Anatomy of the Cerebral Hemispheres, J. D. 

 Cunningham. Cunningham Memoirs of Royal Irish Academy, vii. 



