KONINKLLTKE AKADEMIE VAN WETENSCHAPPEN 

 TE AMSTERDAM. 



PROCEEDINGS OF THE MEETING 

 of Saturday May 27, 1905. 



(Translated from: Verslag van de gewone vergadering der Wis- en Natuinkundige 

 Afdeeling van Zaterdag 27 Mei 1905, Dl. XIV). 



OOZsTTElsTTS. 



L. Boi.iv: "On the development of the cerebellum in man". (First part), p. 1. (With one plate). 



E. VKHSCiiAFrKLT: "Some observations on the longitudinal growth of stems and flower-stalks". 

 (Communicated by Prof. Ilrco dk Vriks), p. 8. 



G. C. J. VosMAKU and H. V. Wijsman: "On the structure of some siliceous spicules of Sponges. 

 I. The styli of Tcthya lyncurium", p. 15. 



Jan db Viuks : "On pencils of algebraic surfaces", p. 29. 



J. J. VAN Laar: "On the sha]ie of the plaitjroint curves for mixtures of normal sid^stances". 

 (2nd Communication) (Communicated by Trof. II.. A. Luiikntz), p. 33. (With one plate). 



J. J. VAN Laar: "Some remarks on Dr. Pii. Koiinstam.m's last i)apers". (Communicated by 

 Prof. II. A. LoRENTz), )). 49. 



W. A. Ykr.sluy.s: "On the rank of the section of two algebraic surfaces". (Communicated by 

 Prof. P. H. Sciioute), p. 52. 



The following papers were read : 



Anatomy. — "On the development of the cerebellum in man.'" 

 (First part). Bj Prof. L. Bolk. 



(Communicated in the meeting of March 25, 1905.) 



On account of the fact that the lobulisation of the adult cerebellum 

 of Primates generally and of man in particular, deviates in various 

 respects from that of the remaining mammals, so that a homologisation 

 of the lobes of the cerebellum of Primates occasionally presents 

 difficulties, I undertook an investigation concerning tJie development 

 of the grooves and lobes of the cerebellum in man, in order to try 

 to elucidate certain obscure points in the anatomy of the Primate- 

 cerebellum in this way. This investigation comprises some forty 

 cerebella of human embryos, varying in length from crown to sole 

 from 5 to 30 cm. 



i 



Proceedings Royal Acad. Amsterdam. Vol. Vlll. 



