1 66 



THE NERVOUS SYSTEM 



The lateral lemniscus has been traced to this nucleus, and while some of the 

 fibers plunge directly into it, others sweep around it to form a capsule, within 

 which it is enclosed. The majority of these fibers ultimately end in this nu- 

 cleus, but some pass beyond it, reach the median plane, and decussate with sim- 

 ilar fibers from the opposite side (Fig. 118). The ramifications of fibers from the 

 lateral lemniscus form an intricate interlacement within the nucleus, and 

 throughout this network are scattered many nerve-cells of various shapes and 



Fig. 118. Semidiagrammatic section through the inferior colliculus of the mouse: A, Nucleus 

 of inferior colliculus; B, gray matter of the lamina quadrigemina; C, inferior quadrigeminal bra- 

 chium; D, central gray substance; K, decussation of the brachium conjunctivum; a, b, c, d, fibers 

 of the lateral lemnisus. Golgi method. (Cajal.) 



sizes. On the medial side of this circumscribed nuclear mass we find some of 

 the laminated gray matter of the tectum, within which are embedded large mul- 

 tipolar cells with axons directed ventrally in the stratum profundum. These 

 partially encircle the central gray matter and after undergoing a partial decus- 

 sation enter the tectobulbar and tectospinal tracts. 



The inferior quadrigeminal brachium begins on the lateral side of the nucleus 

 of the inferior colliculus and consists of fibers from the lateral lemniscus which 



