150 



PHYSIOLOGICAL SERIES. 



has a much wider distribution than the anterior com- 

 missure of most Eutheria, for it connects the whole of 

 the two cerebral hemispheres, excepting the hippocainpal 

 formations only. Now in all Eutheria part of the neopal- 

 1 in in is connected to the other hemisphere by means of the 

 corpus callosum, so that the ventral commissure of the Spiny 

 Anteater represents not only the anterior commissure, but 

 also the corpus callosum of the Eutheria. 



Fig. 41. (Nat. size.) 



FASC . DENT 



MM.D. 



OLF. BULB 



COMM. 



'PYR.L. 



Fig. 42. (Nat. size.) 



CORP. ST. 



,_ "SYL.F. 

 PYR.L/ I 



RHIN . F 



The dorsal or hippocampal commissure (COMM.D.) is 

 much smaller. It was erroneously believed by Flower 

 (Phil. Trans. 1865) to represent the corpus callosum ; Imt 

 as it is wholly derived from the hippocampal formation 

 by means of the fornix, it cannot be strictly regarded :i> 

 the representative of a commissure (the corpus callosum) 

 which is derived from cortical areas (neopallium) other than 

 the hippocampus (Elliot Smith, Proc. Linn. Soc. N. S. W. 

 vol. ix. 1895, p. 635) *. 



* This view, which was originally stated by Owen in 1837, and conclu- 



demonstrated by modern methods by Symington (Journ. Anat. 



Phys. 1802), has recently been called in question by several writers, without 



a tittle of evidence to justify their irrational refusal to recognise a fnct which 



is unquestionable and so easily demonstrable. 



