NERVOUS SYSTEM. VERTEBRATA. 347 



Although the cerebellum conforms to the usual mammalian 

 (and especially Ungulate) plan it presents some very 

 peculiar features. The floccular lobes (figs. 198 & 200) 

 can only be properly described as enormous ; they consist 

 of large, cake-like, compact masses of very complicated 

 character forming the whole of the lateral aspects of the 

 organ. The flocculus (sensu stricto) is a small foliate plump 

 mass, quite distinct from the great parafloccular masses 

 which form the bulk of the floccular lobe. The inter- 

 floccular mass is relatively small ; its lateral portion is 

 marked by a simple transverse pattern, as in most 

 Ungulates ; and its mesial part is reduced to extra- 

 ordinarily small dimensions. 



The references to somewhat unsatisfactory accounts of 



this brain which Murie, Chapman, and Garrod have given 



will be found in the recent note by Beddard, Proc. Zool. 



Soc. 1897, p. 52. 0. C. 1331s. 



Presented by the Zoological Society. 



D. 507. The lateral wall (separated by a sagittal section) of the left 

 cerebral hemisphere of a Manatee (Trichechus latirostris). 



The lower half of the hippocampus is exposed in the 

 descending cornu of the lateral ventricle. The peculiar 

 hippocampal tubercle described in the account of the last 

 specimen is exposed at the lower end of the fascia dentata. 

 The fimbria appears to spread out on its anterior border. 



On the lateral aspect the peculiar Ungulate type of 

 pseudosylvian sulcus is exhibited. 



D. 508. A cast of the cranial cavity of a Manatee ( Triclieclms 

 senegalensis). 



D. 509. A cast of the cranial cavity of a Dugong (Halicore dugong) . 



The brain of the Dugong, as Miklucho-Maclay's account 



shows, closely agrees in structure with that of the Manatee. 



Miklucho-Maclay, Proc. Linn. Soc. New South Wales, 



vol. x. 



D. 510. A cast of the cranial cavity of a Rhytina. 



In spite of its lowly organisation, this brain (according 

 to Brandt) shares with the Elephant and the great Baleen 



