375 



and stained the sections with lithium carmine, which reveals the dense 

 band of stratum granulosum even to the naked eye, as well as the scattered 

 cells which are not so evident. The crucial stages in this series of 

 sections are represented here (Figs. 5 to 11) by drawings made with 

 the Edinger-Leitz projection-apparatus. 



Lobus ant. 



s' , Fiss. prima 

 / Lobus rnedius 



— Fiss. postlunata 



— Lobus flocc. 



Fiss. suprapyr. 



Fiss. secunda 

 Fig. 13. 



Uvula 



Fiss. 

 parafl. 



Fig. 12. 

 Fig. 13. 



The anterior aspect of the cerebellum of Notoryctes typhlops. X 4, 

 The posterior aspect of the same. )x( 4. 



Both parts (uvula and nodulus) of the posterior lobe rapidly 

 dwindle as they are traced laterally (Fig. 5) and the fissura post- 

 nodularis becomes very shallow. By carefully tracing the stratum 

 granulosum in the series of sections it is clear that the uvula does 

 not extend more than 2,5 mm from the mesial plane. 



At that point (compare Figs. 6 and 14 with Figs. 7 and 15) the 

 little mass of stratum granulosum in the uvula comes to an end and 

 the narrow band which joins it to the granular layer of the middle 

 lobe remains separate from the triangular patch in the nodulus. 

 Although the granular masses belonging to the middle lobe and the 

 nodule respectively approach very near the one to the other they are 

 always separated by a narrow clear interval (Fig. 15). The fissura 

 secunda then comes to an end and the tail-like ventral extremity of 

 the stratum granulosum of the lobus rnedius descends on the caudal 

 aspect of the nodulus (Figs. 8 and 16). The ventral extremity of this 

 "tail" then becomes swollen (Fig. 9) and the slender link, which joins 

 it to the rest of the middle lobe, becomes more and more attenuated 

 until it finally disappears (Fig. 17). Then the lower edge of the 

 granular layer of the middle lobe (representing the "copula pyramidis", 

 which I have described elsewhere, op. cit. 7) becomes widely separated 

 from the rest of the granular substance. At this stage, therefore, we 

 find two small masses of granular substance separated from that of 

 the rest of the cerebellum; one of these (the "copula pyramidis") is 

 mesially continuous with the lobus rnedius; and the other, which I 



