372 PHYSIOLOGICAL SERIES. 



occasional blending of parieto-occipital and calcarine snloi 

 in the human brain is quite a secondary development, so also 

 the series of Anthropoi dean brains in this collection clearly 

 shows that the parieto-occipital sulcus makes its first ap- 

 pearance in the Cebidae as a sulcus obviously compensatory 

 to an already Y-shaped calcarine complex. Moreover t lien- 

 is no parallel anywhere in the Anthropoidea fora Y-shaped 

 complex of calcarine and parieto-occipital sulci except 

 occasionally in the human brain. If, however, it be urged 

 that the Lemurs are reversionary forms, which arc not 

 strictly comparable with the lowlier Apes, it remains to be 

 explained how Daubentonia and Manis (the calcarine sulci 

 of which are essentially identical with those of the Lemurs) 

 came to assume the form they present *. 0. C. 1337 A />. 

 W. H. Flower, Phil. Trans, vol. clii. 162, p. 195. 



D. 535. The brain of a Black-faced Lemur (Lemur mgrifront)^ 

 from which almost the whole of the right cere Krai 

 hemisphere and a considerable part of the left have been 

 removed. In the left hemisphere the whole of the ventri- 

 cular surface of the hippocampus [major] has been exposed, 

 and a purely artificial posterior cornu of the lateral ventricle 

 has been made. The latter and the calcar avis lying in it 

 are seen to be relatively smaller than the corresponding 

 parts in many of the Oebidae. 



The small oblique optic thalami and the typical corpora 

 quadrigemina are exposed. On the right side, the -whole 

 extent of the large optic tract and prominent external 

 (anterior) genicubite body are clearly demonstrated. 



There is a large projecting mesial (posterior) geniculate 

 body and a very prominent tract us peduncularis tran>- 

 versus. 



The features of the typically .-imple cerebellum, which 

 resembles that of the Viverridse and Sloths and manv 

 other lowly mammals, stand out very distinctly. 



0. C. i:'.:;7 \c. 

 Flower, Phil. Trans, vol. clii. 1862, p. 195. 



* Further investigations (made since this was written) have convinced 

 me that the apparent anterior limb of the Y-shaped calcarine group of sulci 

 represents the more ventral of the two elements of which tin- tin. Simian 

 parieto-occipital sulcus (vide infra) is composed. 



