1882.J Central Nervous System in Vertebrate Animals. 401 



this presents the four layers usually found in the corresponding lobe in 

 the teleostei, namely, counting from the outside, the molecular, the 

 intermediate — which incl tides the Purkinje cells — the granular, and 

 the fibrous ; the latter consisting of nerve-fibres on their way to the 

 crura cerebelli. 



Noticing Denissenko's* paper, and his discovery of two species of 

 cells in the granular layer of the cerebellum, the author remarks that 

 he was unable to find them, even by using Denissenko's own method. 

 He then discusses the cause of the striation in the molecular layer, 

 which he attributes in a great measure, but not entirely, to prolonga- 

 tions from the epithelial layer of cells which cover the surface of the 

 cerebellum. Incidentally he mentions that he has traced an axis 

 cylinder process of a Purkinje cell into amedullated nerve-fibre. 



He then goes on to describe the structure of the organ in front of 

 the cerebellum. This he finds consists of two parts, a central con- 

 tinuation of the cerebellum, having precisely the same structure and 

 arrangement, and two lateral parts spreading out one on each side, 

 like wings. 



The plates which form these lateral wings consist of minute cells, 

 resembling those found in the granular layer of the cerebellum. 

 Each ridge has four layers corresponding to those found in the 

 cerebellum, arranged in a slightly different manner. The molecular 

 layer comes first, then the granular and intermediate layers mingled 

 together, and last of all, the fibrillse from the fibrous layer. The 

 molecular layers of contiguous ridges are placed in close contiguity 

 with, a process from the pia mater interposed between them ; the 

 granular and intermediate layers come next, consisting of cells of 

 different sizes, connected together by a network of fibrillse. The 

 smaller cells resemble those of the granular layer of the cerebellum ; 

 the larger ones are intermediate between the last, and the Purkinje 

 cells to which they lead up. These latter are arranged in a single 

 layer; they are smaller in size than the corresponding cells in the 

 cerebellum, and usually oval or fusiform in shape ; they generally have 

 two processes, one, the protoplasmic process, directed towards the 

 molecular layer, and the other the axis-cylinder process, turned 

 towards the bundle of fibrillas which is derived from the fibrous layer, 

 and which, passing between two contiguous ridges on the side 

 opposite the molecular layer, forms the boundary between them. 



In some parts, however, these cells are arranged in groups, viz., 

 where the bending of the wings causes bays and recesses in the 

 ridges ; here they are polygonal in shape and present several processes. 

 The sides of the ridges are inserted into the plates or wings of granular 

 layer cells, by conical processes. 



* " Zur Frage ii. d. Bau d. Klemliirnriude," " Arch. f. Mik. Anat.," Bd. xiy, 1877. 



