451 



For mechanical reasons such a sulcus is usually prolonged in both 

 directions far beyond the area striata, the long axis of which it cuts 

 at right angles. 



In the large Ungulata and the Seals the posterior end of the 

 hemisphere is often distinctly elongated above the cerebellum and the 

 altered mechanical conditions produce a totally different form of intra- 

 striate sulcus — a folding in the direction of the long axis of the 

 striate area i. e. at right angles to the postsplenial sulcus of the smaller 

 Carnivora and Ungulata. This axial form of sulcus usually joins the 

 praestriate sulcus. The same type of "calcarine" sulcus i. e. a con- 

 joint praestriate and intrastriate sulcus is realised in all the Prosimiae 

 and in xVJan (as a general rule). In the Apes (Hapalidae, Cebidae, 

 Cercopithecidae and Simiidae) the visual cortex attains to a very large 

 size in proportion to the rest of the neopallium: in other words, its 

 rate of growth must be (and, as a matter of observation, is) very 

 rapid compared with that of the neighbouring cortical regions: as the 

 result of this precocious expansion the whole of the uiesial part of the 

 area striata becomes buckled in and submerged in the great fossa 

 striata, which entirely swallows the insignificant prestriate furrow (the 

 true calcarine sulcus). In the human brain (in most cases) the great 

 disproportion between the rates of growth of the striate and non- 

 striate cortical regions becomes more nearly balanced again — but not 

 so much by any noteworthy actual reduction in the size of the area 

 striata as by the great expansion of the cortical areas surrounding 

 the visual centre. One result of this is that the mechanical conditions 

 approximate more nearly to those which operate in many non-Primate 

 mammals and the prestriate (true calcarine) sulcus once again assumes 

 its pristine importance. 



Nachdruck verboten. 



Zur vergleichenden Anatomie der Pyraniidenbalin. 



Von Dr. Kukt Goldstein, Assistent des Institutes. 



[Aus dem Dr. SEXKENBERGschen neurologischen Institut in Frankfurt a. M., 



Direktor Prof. Dr. L. Edinger.] 



Mit 3 Abbildungen. 



Bei allen Säugern liegen in den Ventralsträngen der Oblongata 

 zwei Stränge, die man den Pyramiden des Menschen gleichgestellt hat. 

 Wir besitzen über die äußere Form dieser Pyramidentractus bei Tieren 



29* 



