:\10HPll()L0Gr OF THE RRAIX IX THE MAMMALIA. 42!) 



middle lobe is mueli more deeply incised, /. e. has a much more extensive surface than 

 that of all other mammals of a corresponding' size. 



Wherefore the cerebellum of Tarsius exhibits definite signs of superiority over that 

 of other mammals when it is studied in mesial section. 



The resemblance of the surface of the cerebellum in TarshiH to that of other small 

 mammals is much closer than one might expect from a study of the mesial section. 



The two lobules (nodule and uvula) of the posterior lobe extend outward for a short 

 distance only and then seem — to the naked eye — to stop abruptly. If, however, a series 

 of sections be examined microscopically, this lobe will be found to extend outwards as au 

 exceedingly attenuated baud of cortex which suddenly expands upou the lateral aspect 

 of the middle peduncle of the cerebelkun to form a sliort plump bilobulated mass — the 

 llocculus. 



The pyramid (which is the ventro-caudal lobule of the middle lobe) is ])rolonged 

 outward into a broad band on the caudal aspect of tlie cerebellum. It arches outward 

 and downward parallel to the margin of the uvula, so that it reaches the lower margin 

 of the cerebellum. It then passes forward and expands, just above the lioccidus, into a 

 narrow, widely-projecting rod of cortex — the paradoceulus. 



This parafiocculus is enclosed in a bony capsule ibrnied by the petrous temporal. 

 It is that iiart of the floccular lobe which is commonly called tlic " flocculus," but it is 

 not the flocculus of Human Anatomy. 



The cortex on the upper side of the paraflocculus is divided into a series of five or six 

 bands by means of shallow notches. The under surface is smooth. The distal extremity 

 is bifid. 



It is the distinctness of the broad cortical band joining the pyramid to the para- 

 flocculus A\liicli specially emphasizes the resemblance of the cerebellum in Tarsin.s and 

 that found in the generalized mammals. In most Primates this simple relationship 

 becomes so completely disguised as to be quite unrecognizable. 



Por reasons Aviiich will appear later, it is desirable to have some term Avitli which 

 to distinguish the ])and of cortex linking the pyramid to the parafiocculus. I shall 

 therefore call it the " copula pyramidis." Exactly how much of the uniform band 

 (in Tui-sius) is pyramid and how much is copida, will be appreciated later when the 

 different fate of the two parts will be studied. 



The copula pyramidis forms the lowermost lobule of the lat(n-al part of the middle lobe. 



The rest of the latter is subdivided into three parts, which I distinguished by the 

 letters A, B, and C in rhe Edentate cerebellum [op. cit.). 



The area A is a simple band which forms the posterior lip of the fissura prima 

 and extends outwards and forwards (on the anterior or cerebral surface) as far as tlir 

 parafiocculus. 



The area B is a little rounded knob which forms the most laterally-projecting part 

 of the so-called " lateral lobe " of the cerebellum. It is subdivided into three folia l)y 

 means of two deep fissures. The area B is wedged in between the lateral extremities ol' 

 the areas A and C, and is connected to the mesial part of the middle lobe only by a very 

 narrow stalk, the limiting furrows of which are alwavs shallow and sometimes absent. 



