3S4 



PROF. G. ELLIOT SMITH ON THE 



been categorically denied hy Ziehen *. He states that ia the brain of Pleropiis niedius 

 (which is identical with that of P. poUocepludus ■\) none of the sulci which he labels 

 TT, o, and p in the Lemurs (corresponding respectively to the paracalcarine, calcarine, 

 and retrocalcarine of my account) are present; but he believes the sulcus a (the 

 intercalary of these notes) to be prolonged backward around the splenium. It is quite 

 unnecessary (because the discrepancy is so obvious) to point out hoAv little accord there 

 is between this view and that held by the same writer with regard to the Carnivora 

 and Cetacea. 



The comparison of the section th'-ough the hemisphere of Pteropus (tig. 54) wath 

 that of Lemur and C'anis is quite sufficient to show the identity of the conditions in the 

 three forms. 



F12-.546. 



Fig. 54 a. — Pleropus 2'>oUocephahts. Mesial aspect of the right cerebral hemisphere. X .3. 

 Fig. 54 6. — Pferopiis j)ol{ocfj)hah(s. A horizontal section through the posterior part of the 

 hemisphere in the plane y (fig. 51 a). 



In order that the relationship of the calcarine sulcus to the retrocalcarine and para- 

 calcarine sulci may be rightly appreciated and its systematic value may be correctly 

 appraised, it is necessary to consider certain other aspects of this problem. 



Tlie exaggerated importance which Owen "^ had attached to the calcar avis or so-called 



* -Irch. f. rsychiat. ISyO. 



t ^ide Gustav Eetzius, " Zur Morphologie der Fascia Dentata," &e., Biolog. Unters. X. F. viii. 3, Taf. 14. fig. 3. 



j Froc. Linn. Soc. TS5S ; also Annals & Mag. Xat. Hist., June 1S51, Eede I/ecture, and elsewhere. 



