LEMUR MONGOZ 



35 



there are faint indications of the pyramidal decussation. Some crossing pyram- 

 idal strands remain close to the surface and these partially interrupt the 

 ventromcdian sulcus at this level. 



FIG. 17. BASE OF BRAIN, LEMUR MONGOZ. 

 (White dots are due to salt precipitation in fixative.) 



The rather feeble relief both of the pyramids and the inferior olives is 

 taken to indicate a comparatively low organization in spheres of action which 

 these two structures represent. In the case of the relatively insignificant 

 pyramids the cortico-spinal connection between the motor cortex and spinal 

 cord must be regarded as correspondingly small and volitional control of 

 motion but poorly developed; likewise, in the case of the inferior olive, the 

 lack of surface prominence suggests a relatively low degree of organization in 

 the reflex control of simultaneous movements in eyes, head and hands, and in 

 the facilitation of the coordination of all skilled learned performances. 



The cephalic extremity of the oblongata on its ventral surface comes to 

 an abrupt termination in the slight elevation produced by the pons Varolii, 



