THE CEREBRAL HEMISPHERES 153 



Orolestes has not been completed, but in a simple in- 

 sectivorous animal, Macroscelides, as figured by- 

 Elliot Smith (1924), we see an arrangement which is 

 probably equally primitive. This drawing is here re- 

 produced as Figure 35. 



Fig. 2S' — Brain of the jumping shrew, Macroscelides, illustrating the 

 cortical areas. After Elliot Smith (1924). The neopallial areas above the 

 rhinic fissure (cf. Fig. 32) are conventionally shaded. In front, the area of 

 coarse dots is the motor cortex; the cross-hatched area is somesthetic; 

 and these two fields probably overlap extensively. Behind and above, 

 the visual cortex is marked with fine dots; below this is the temporal or 

 auditory area. The insular cortex, marked with vertical lines above the 

 rhinic fissure, is the least highly specialized neopallial area. 



The cerebral cortex of the opossum has been 

 minutely studied by Gray (1924), and the areas which 

 can be distinguished by differences in cortical struc- 

 ture are shown in Figure ^6. The cellular arrange- 

 ments of two of these areas have already been illus- 

 trated (Figs. 13, 14, p. 85). The area striata (a, str.y 

 no. 17 of Brodmann) is clearly visual cortex; the area 

 temporalis {a. temp.y no. 22 of Brpdmann) is probably 

 auditory; the tactile and somesthetic field is probably 

 in the postorbital {a.porb.) and parietal (<2.^^r.) areas 

 of Gray behind the orbital fissure {fs. orb^^ but this 

 has not been experimentally verified. 



