70 THE CEREBRUM. 



border is separated from the limbic lobe by the collateral fissure 

 and by a short furrow, which is shallow in the adult human brain, 

 called the sulcus ecto-rhinalis. The temporal lobe is attached 

 to the hemisphere posteriorly and medially; but it presents three 

 free surfaces a superior, an external and an inferior which meet 

 at the anterior point, called the temporal pole. 



The superior surface of the temporal lobe forms the inferior 

 wall of the lateral cerebral fissure (Fig. 25). It looks somewhat 

 medianward toward the island and constitutes the temporal part 

 of the operculum. It is separated from the island by the inferior 

 circular sulcus (s. circularis insula). Anteriorly, the superior 

 surface of the temporal lobe is smooth; posteriorly, it possesses 

 one or two shallow transverse temporal sulci which feebly outline 

 two or three gyri, called the transverse temporal gyri of Heschl 

 (gyri temporales transfer si). These transverse gyri belong to 

 the receptive auditory center (Figs. 31, 35, 36 and 54). 



The external surface of the temporal lobe presents the fol- 

 lowing sulci and gyri (Figs. 23 and 24): 



f Superior temporal (s. temporalis superior) 

 J Middle temporal (s. temporalis medius) 

 } Inferior temporal (s. temporalis inferior). This is 

 really on the inferior surface of the lobe. 



f Superior temporal (g. temporalis superior) 

 Gyri <j Middle temporal (g. temporalis medius) 

 [ Inferior temporal (g. temporalis inferior). 



The superior temporal and middle temporal sulci (Fig. 23) di- 

 vide the external surface into three nearly equal gyri; they run 

 parallel with each other, with the infero-lateral border and with 

 the lateral cerebral fissure. The superior temporal sulcus, like 

 the lateral fissure, bends upward at its posterior extremity; it 

 terminates in the concavity of the angular gyrus. The middle 

 temporal sulcus is usually an interrupted one. It may present 

 an upward curve at its posterior end which is bounded and closed 

 by the post-parietal gyrus ; or it may continue in its original direc- 

 tion toward the occipital lobe. 



The inferior temporal sulcus, situated in the tentorial area of 



