Literary Notices. v 



the expansion of the cranial cavity, and a restoration of growth-har- 

 mony between skull and brain. 



7. Consequently it is only in Primates, which alone possess 

 well-developed occipital lobes, that transitory infoldings of the cere- 

 bral walls in all probability exist. 



8. The two transitory fissures which do not disappear before the 

 full development of the corpus callosum are : — {a) the external calcar- 

 ine, and (b) the external perpendicular fissure of Bischoff. In point 

 of fact the latter fissure does not appear until after the full develop- 

 ment of the corpus callosum. 



9. The external calcarine fissure produces an infolding of the 

 outer wall of the posterior horn of the lateral ventricle, which pre- 

 sents the same direction, and lies immediately opposite to the true cal- 

 carine infolding, or the calcar avis. 



10. The fissure corresponding to this in apes is, as a rule, per- 

 manent, and in some species its anterior end forms in the adult, a 

 bulging on the outer wall of the ventricle. 



11. The external calcarine fissure disappears before the sixth 

 month of foetal life in man. 



12. The external calcarine fissure is present on the outer surface 

 of the foetal cerebrum from the beginning of the fifth month to the 

 end of the sixth month. 



13. It is a complete fissure and corresponds to the "Affen- 

 spalte " on the ape's brain. 



14. The " Affenspalte " on the ape's brain is also a complete 

 fissure, and presents a well-marked bulging on the outer wall of the 

 posterior horn of the ventricle ; but, unlike the external perpendicu- 

 lar fissure of the human foetus, it is permanent. 



15. Certain fissures, therefore, which are complete and tempo- 

 rary in the human brain are complete and permanent in the ape's 

 brain. 



16. The complete permanent fissures in the human are : — (a) 

 the fore part of the calcarine; (b) the hinder part of the fissura ar- 

 cuata ; (c) in many cases the parieto-occipital ; and (d) in some cases 

 the mid-collateral. The Sylvian fissure is not a complete fissure. 



17. Of the fissura arcuata the hinder part alone is preserved as 

 the fissura hippocampi. The fore part, which is generally supposed 

 to be retained as the callosal fissure, is in reality obliterated. 



18. Synchronous with the appearance of the radial transitory 

 fissures on the mesal face of the hemisphere two fissures appear, 

 which he in series with the former and occupy the ground afterwards 



