356 



ANATOMY OF THE RABBIT 



These are separated by a faint median depression, the 

 interpeduncular fossa, just behind the mamillary body. 

 The superficial portion of each peduncle is composed of a 

 broad white band of longitudinal nerve fibres and contains 

 the main descending pathways carrying impulses from the 

 cerebral cortex to the cerebellum and to the motor centres 

 of the brain and spinal cord. 

 (c) The third cranial, or oculomotor nerve (n. oculomotorius), 

 which controls the majority of the eye-muscles, emerges 

 from the ventral surface of the cerebral peduncle. 



THE rhombencephalon: 



(a) The cerebellum forms a dorsal arch over the anterior part 

 of the hindbrain and is supported by stout pillars at its 

 sides. The dorsal part of the arch has become very mas- 

 sive, is moulded into several lobes, and has a superficial 

 layer of grey matter, the cerebellar cortex. This is thrown 

 into numerous transverse folds. The subdivisions recog- 

 nized include a median portion, the vermis, a cerebellar 

 hemisphere at each side of this, and a stalked body, the 

 paraflocculus, arising ventrolateral^ beneath each heml- 

 phere. 



The flocculus is a small fold ventral to the stalk of each para- 

 flocculus. 



Left lateral surface of cerebellum of the rabbit. 



Fig. 119. Median section of cerebellum, the cortex stippled. Both figures after 

 Brodal. Ans, lobulus ansiformis; Ant, lobus anterior; F, flocculus; fp, fissura 

 prima; fpp, fissura prepyramidalis; fs, fissura secunda; LMM, lobus medius 

 medianus; N, nodulus; P, pyramis; Pf, paraflocculus; Pm, lobulus para- 

 medianus; sun, sulcus uvulonodularis; U, uvula; 1, lingula; 2, lobulus centralis; 

 3, 4, culmen; 1-4, lobus anterior. 



