304 



ON THE ANATOMY OF 



P.Z.S. 1882, 

 p. 295. 



lobe " has, on its inferior aspect, a few irregular dentations developed 

 near its antero -internal angle. 



In the smaller and simpler brain of Tamandua (represented diagram- 

 matically in fig. 5), the only sulei present are those corresponding to 

 7&, c in the larger species, with some slight representatives of d. 



Adopting the late Prof. Broca's ideas * as to the nature and com- 

 position of the " scissure limbique" the inferior arc of this is clearly repre- 

 sented by the fissure a, which is separated by a narrow "pli de passage 

 retro-limbique" (fig. 4, r.l) from its superior arc, represented by what we 

 commonly call the " calloso-marginal sulcus " (c.w, &c.). The slight 

 sulcus at s, developed above the triangular depression, will accordingly be 

 the Sylvian fissure, b is then, following Broca's identifications, the 

 fissure of Eolando, the gyrus lying anterior to and below it being the re- 

 duced equivalent of the frontal lobe. As has already been pointed out, 

 this gyrus is connected posteriorly by a small, sometimes deep, bridging 

 fold with the triangular space (Ls.s.) below the Sylvian fissure. This 

 triangular space is Broca's " lobule sous-sylvien" its equivalent in the 

 Primates being the lobe of the island of Reil (1. c. p. 430). 



The longitudinal sulcus c corresponds probably to Broca's " sillon 

 parietal primaire " the gyrus above and internal to it will thus be the 

 "circonvolution sagittale" that below it the "cir convolution sylvienne," which 

 in the more-convoluted of the brains (fig. 3) becomes divided up by 

 smaller sulci (d, e, &c.) into a number of imperfect gyri. 



Fig. 5. 



rJ, 



Diagram of right cerebral hemisphere of Tamandua tetradactyla, from above. 



From my study of the brains of the remaining genera of Edentata, I 

 have little doubt that the sulci a, b, and c, here described, can be traced, 



* " Anatomie comparee des circonvolutions cerebrales. Le grand lobe limbique 

 et la scissure limbique dans la se"rie des Mammiferes," Revue d'Anthropologie, vii. 

 pp. 385-498. 



