( ^^ ) 



the sulcus primarius (1) and the flssura secunda (2). This groove, 

 indicated in the following figures by 4, is the sulcus praepyramidalis 

 (mihi) (sulcus inferior posterior of Ziehen, fissure suprapyramidalis 

 of Elliot S."\iith, fissure III of Charnock Bradley). This fissura 

 praepyramidalis borders in front the pyramis and soon reaches the 

 length of the fissura secunda. This latter can in its further develop- 

 ment lengthen itself regularly in a lateral direction, or otherwise 

 there independently arises (fig. 8b 2') in the hemisphere at a short 

 distance above the , fissura paratloccularis {j>) a groove which soon 

 becomes confluent with the fissura secunda. While at the same time 

 the recessus laterales bend out further, the fissura paratloccularis 

 (fig. 7b, Sb, p) becomes confluent with the sulcus uvulo-nodularis, 

 by which the gyri flocculares form with the nodulus a part which 

 is marl\ed off from the remainig cerebellum. Elliott Smith mentions 

 that the fissura paratloccularis can also flow^ together with the fissura 

 secunda (2). This observation I can confirm for other mammals on 

 account of the structure of the adult cerebellum ; with the embryonic 

 material of man I have not observed such a case. At a later stage 

 the fissura secunda does terminate, above in the fissura paratloccularis. 

 In the cerebellum of a foetus of 13 cm. the hemispheres are no 

 longer swollen balloonlike, but have, wiien seen from behind, obtained 

 the more angular form which now is characteristic for them during 

 a longer period of development (fig. 9c/). Tiie median zone is still 

 a little depressed, even in the posterior part of the lobus anterior. 

 The sulcus primarius (1) lies still relatively far at the back, the sulcus 

 praepyramidalis (4) has already pretty far advanced into the hemis- 

 pheres, but in such a way that the lateral parts with the transversally 

 proceeding middle part form an obtuse angle, witli the opening 

 downwards. This peculiar siiape forms during the successive stages 

 of development, in which the interpretation of the grooxes is not 

 always easy, an excellent diagnostic for the sulcus praepyramidalis. 

 The fissura secunda (2) has advanced as far as the lateral wall of 

 the cerebellum so that the regio tonsillaris (fig. da t) is now bordered 

 on all sides. This region is always more or less swollen in the shape 

 of an egg. The gyrus floccularis is divided by a longitudinal groove 

 into two small lobes. At this stage consequently the uvula with the 

 appertaining lateral parts and so also the noduhis with its lateral 

 regions are already differentiated in principle. This rapid developmental 

 process contrasts strongly with the still very simple condition found 

 in the remaining part of tiie lobus posterior and supports to some 

 extent the opinion of Elliott Smith who looks upon the complex 

 of uvula with tonsils, nodulus with flocculi, as a more independent 



