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fact that a thin neopallial bladder (which has become softened as the 

 result of post-mortem partial decomposition) will tend to collapse and 

 become wrinkled: the resultant folds of soft, plastic neopallium will 

 easily become exaggerated and stretch the surface. Whatever the 

 explanation may be, the irrefutable fact remains that in all the fresh 

 brains of the 3rd and 4th months no such "fissures" are present; and 

 there seems to be no just reason for regarding them as other than 

 post-mortem deformities. 



So far as I am aware, no doubts have ever been cast on the 

 genuineness of the so-called "transitory fissures", which are described 

 as being present in the 5th, 6th and 7th months. Yet, if the chief 

 of these — Bischoff's "Fissura perpendicularis externa" — is really 

 transitory, it cannot be the representative of the sulcus occ. lunatus, 

 seeing that I have demonstrated the existence of the latter in the 

 normal adult brain. 



In a series of human foetuses of the 5th and 6th months, which 

 I possess, I have found that whenever such a furrow (Fig. 1, «) as 

 BiscHOFF, Ecker, Cunningham and Retzius describe and figure as 

 the "Fiss. perpend, ext." is present, it is invariably causally - related 



Fossa par. occ. 



Fig. 1. The head of a human foetus at the beginning of the f5th month, witli 

 the left lateral aspect of the brain exposed. X ^1-- "'■ Post-mortem furrow opposite 

 the lambdoid suture, [i Post-mortem furrow opposite the coronal suture. 



to a ridge (Fig. 2, x), formed by the inward-folding of the membrane 

 joining the occipital and parietal bones in the lambdoid sutural line. 

 The furrow a is obviously nothing else than a post-mortem indentation : 



