MORPHOLOGY OF THE CEREBRAL CONVOLUTIONS. 257 



run forward and merge with the gyrus hippocampi and gyrus cinguli running 

 around the splenium corporis callosi, and to these are joined the gyrus fornicatus 

 and convolutions of the island of Reil or central lobe. According to Bischoff, 

 Huschke's explanation is particularly imperfect, because it leaves the convolutions 

 lying behind the central convolutions in obscurity. It also suffers from an imper- 

 fect and unsuitable nomenclature and from the failure to recognize a distinct 

 parietal and occipital lobe. 



Reichert 1 avoided a topographical description of the convolutions of the brain. 

 He studied more particularly the development and structure in the human foetus, 

 and he is of the opinion that the type in the complicated structure of the human 

 brain is to be explained by its embryological history. He also calls attention to 

 the fact that the characteristic form and arrangement shows a remarkable corre- 

 spondence with the type of branching and course of most of the central vessels. R. 

 Wagner 2 in his studies of the human brain added nothing of importance to the 

 results of Huschke and Gratiolet. He distinguished three frontal, three parietal, three 

 occipital and three temporal convolutions, but entirely excludes the plis de passage of 

 Gratiolet from the description of the convolutions as found in the human brain. 

 He did not succeed in establishing any better characteristics of the occipital and 

 temporal lobes than did his predecessors. Both Reichert and Wagner added little 

 or nothing to the doctrine of the general arrangement of the convolutions, but 

 Wagner's work was of service in giving general distribution to the facts already 

 knowm. 



In 1866 Pansch 3 described the convolutions as found in Man and the Simians. 

 On the frontal lobe he points out three fissures and corresponding convolutions. He 

 also describes those found on the orbital surface and includes the anterior central 

 convolution in this lobe. On the parietal lobe he distinguishes only two convolu- 

 tions externally ; viz.: a gyrus parietalis superior and a gj'rus parietalis inferior. 

 The superior parietal convolution includes the posterior central convolution and 

 Huschke's vorzwickel or precuneus ; or Gratiolet's deuxieme pli ascendant plus the 

 plis de passage superieure externe et interne. The inferior parietal convolution is 

 equivalent to Huschke's lobulus tuberis plus the ascending branch of the posterior 

 parietal lobule, or equals Gratiolets pli courb'e with the pli de passage externe 

 inferieure. On the inner or mesial surface he considers only one convolution, the 

 gyrus fronto-parietalis, the so-called arched convolution or gyrus cinguli. 



On the occipital lobe he points out a gyrus occipitalis superior, medius et infe- 

 rior which correspond closely with the divisions of Gratiolet and Wagner. 

 In the same manner on the temporal lobe he recognized a gyrus temporalis superior, 

 medius et inferior and on the lower mesial surface a gyrus occipito-temporalis lateralis, 



1 Der Bau des menschlichen Gehirns, 1859. 



2 Ueber die typischeu Verschiedenheiten der Windungen der Hemisphiiren, etc. Gbttingen, 1860-1862. 

 Vorstudien zu einer wisseuschaftlicheii Morphologic and Physiologie des menschlichen Gehirns und 

 Seelenorgan. Gott., 1862-1864. 



3 Habilitationschrift, De Sulcis et Gyris in Cerebris Simiarum et Hominum, Kiel. 



