Stroud, Mammalian Cerebellum. 97 



61, show its early form and the method of its development. 

 In man, the lateral portions of both flocculus and paraflocculus 

 form the chief mass of these structures. They are compressed 

 and forced laterad by the enormous growth of the postpileum 

 which finally overshadows and dwarfs them. Their mesal ex- 

 tensions are submerged by the growth of adjacent parts ; they 

 apparently exist only as bundles of fibers running to the post- 

 vermis, imbedded in the foundation mass of alba. Compare 

 Figs. 65, 70. 



The rami. — If we retain the old idea of comparing the 

 cerebellum to a tree, the mesal aspect shows that it consists of 

 two enormous branches — preramus and postramus. The post- 

 ramus is much the larger. 



The preramus. — It appears that at an early stage of devel- 

 opment a deep transverse cleft — the furcal sulcus — appears. It 

 divides the cerebellar mass into two unequal portions. The pre- 

 ramus, the cephalic, is the smaller and forms the cephalo-mesal 

 portion of the organ, which lies cephalad of the furcal sulcus. 

 See Figs. 64, 66, 6j, 74. It is relatively much smaller in the 

 lower mammals than in man. The preramus includes the 

 regions recognized as, (i) lingula, (2) cephalic lobe, (3) central 

 lobe, (4) culmen, and their lateral extensions. 



The postramus. — This includes the remaining and by far 

 the greatest mass of the cerebellum. It comprises the follow- 

 ing mesal parts and the lateral masses connected with them, 

 viz., (i) the clivus, (2) the cacumen, (3) the tuber, (4) the 

 pyramis, (5) the uvula, (6) the nodulus. 



In man the clivus and its lateral prolongations constitute 

 the prepileum. In the cat, the clivus, the cacumen, and the 

 tuber with their lateral extensions constitute the prepileum. In 

 man the peduncular sulcus separates the the pre- from the post- 

 pileum ; but the peduncular sulcus of man does not correspond 

 to the interpilear sulcus of the cat. 



For an idea of the extent and mass of the prepileum in 

 man consult Figs. 6^/ and 66, or the part lying cephalad of the 

 peduncular sulcus. 



The postpileum comprises the remaining five lobes of the 



