56 A Reconstrudion of the Nuclear Masses in 



continues laterally as a somewhat convoluted furrow, giving off short, super- 

 ficial sulci; and after deviating somewhat in a caudal direction, it ends by 

 becoming superficial over the lateral portion of the inferior half of the 

 cephalic lobe. Just above the caudal branch of the transverse secondary 

 fissure considered, but separated from it by a gyrus of the superior portion 

 of the cephalic lobe, is a shallow and short furrow, projecting cephalad and 

 laterally to end upon the most cephalic portion of the lobe. Just mesial to 

 the upper end of this short sulcus is a long and somewhat deeper furrow 

 which runs mesially in a straight line for some distance and then abruptly 

 turns caudally and again medially to end superficially at the upper end of 

 the hilum (figures 6 and 7). These constitute the fissures of the cephalic 

 dorsal lobe of the olive; the gyri are quite small in the upper half of the lobe, 

 while in the lower half two large gyri occur, in addition to several small 

 cephalo-caudal gyri. The most lateral gyrus of the inferior half overlies 

 the middle lateral lobe (figures 2, 5, and 7). 



Caudal to the first main fissure (o) and cephalic to the second trans- 

 verse fissure (b) lies the second dorsal lobe of the inferior olive (figure 7). 

 It is small, being limited on the mesial surface by the hilum, and on its 

 lateral aspect by the deep cephalo-caudal furrow. It consists of but one 

 main convolution, divided into rather narrow and short gyri which wind 

 between a caudal secondary fissure from the first main transverse sulcus 

 and two cephalic furrows from the second main fissure. In the main the 

 long axis of this lobe is exactly transverse, but laterally the lobe is continued 

 caudally in a narrowing sjiur lying between the cephalo-caudal and the 

 second transverse fissures. This spur dips increasingly deeply into the 

 furrow beneath the general plane of the dorsal surface until at its termina- 

 tion it lies in the dejiths of the furrows. 



Limited by the hilum on the mesial side, bj' the second (6) and third 

 (c) transverse sulci cephalad and caudad respectively, and the inferior 

 I)ortion of the cej^halo-caudal fissure laterally, occurs the third dorsal lobe 

 (figure 7). In a similar sense this lobe also consists of one main convolution, 

 as in the new-born babe's medulla. But this convolution is marked by 

 many gyri which wind back and forth in a cephalo-caudal direction. The 

 general axis of this lobe lies transverse in the mesial one-third, but laterally 

 to this there occurs a caudal deflection of the whole convolution. The mesial 

 one-third of the lobe is marked off laterally by a caudal fissure, which arises 

 from the depths of the second transverse sulcus (6) and rapidl}' becomes 

 superficial, to vanish over the rather broad gyrus which projects caudally 

 as a peculiar spur into the third transverse fissure (c). Mesial to this caudal 

 fissure, there arise from the second transverse sulcus two rather sujierficial, 

 (caudally directed furrows, which aid in jjroducing the gyri of the superior 

 ])art of the lobe. Lateral to the caudal fissure from the second transverse 

 sulcus is a small and superficial fuirow, directed caudally, just mesial to the 

 ])()iiit of fusion of tlie cephalo-caudal and transverse sulci. From this 



