460 PHYSIOLOGICAL SERIES. 



The cerebellum exhibits an interesting phase, for it 

 consists of two primitive laterally placed rudiments united 

 across the middle line by a narrow bridge. 



[Wax models of this and the following five specimens 

 are in Guy's Hospital Museum.] 0. C. 1341 A. 



Presented by John Hilton, Esq. 



Hochstetter, Bibliotheca Medica A : Heft 2, 1898. 



D. 676. The whole central nervous system of a human foetus, 

 somewhat older than the last specimen. 



The brain is partially divided by a mesial sagittal 

 section. 



The pyriform lobe is recognisable as an acutely-bent 

 band fringing the locus perforatus anticus, ending pos- 

 teriorly in a swollen extremity on the temporal pole. 



External to it we see a slight depression on the lateral 

 wall of the hemisphere, representing the fossa Sylvii, the 

 dorsal limit of which is marked by a faint furrow the 

 superior limiting sulcus (suprasylvian sulcus of other 

 mammals) . 



On the mesial surface of each hemisphere there is a deep 

 irregular furrow resulting from post-mortem softening of 

 the thin-walled hemisphere, and its consequent collapse. 

 This was until recently supposed to bo a real sulcus 

 sulcus arcuatus (" Bogenfurche " of German, writers), 

 but Hochstetter has recently shown it to be a post-mo i -torn 

 change. 



Note that the cerebellar bridge is broader than in the IaM 

 specimen, but that the lateral masses are still much plumper 

 than the mesial bridge. 0. (.. 1:5 1 1 r- 



Presented !>>i J/u>. 1 1 II Ion. A,'*/. 



Gustav Retzius, " Das Menschenhirn," 1896. 



D. 677. The body of a human Fwtus (older llian last specimen)) 

 directed to show the whole cent nil nervous s\>tem in M'/W. 

 The fossa Sylvii is no\\ much deeper and its superior and 

 inferior limiting sulci quite definite. 



On the inoial wall of the hemisphere the calcarine 

 sulcus has now made its appearance. 



