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16 



Commiinicatiuns of tlie ,Jnsti(ii( International crFmhryoIogie* 



(Emhryological Section ol tlie I.U.B.S.) 



The Bonrd of the I. I.E. is constituted as follows: 



Prof. Dr. A. M. Dalcq, President (member of the Board since 1948) 



Prof. Dr. F. E. Lehniann. Secretary-treasurer (1949) 



Prof. Dr. P. A. Weiss, Vice President (1949) 



Prof. Dr. S. Ranzi. Vice President (1957) 



Prof. Dr. Et. C. Wolff. Vice President (1957) 



Dr. H. B. Fell. Member (1952) 



Prof. Dr. S. Horstadius. Member (1956) 



Dr. P. D. Nieuwkoop, Adjunct Secretary-treasurer 



The next General Assembly will be held at Pallanza, Italy, at the end of 

 August or the middle of September. 1960. along with a Symposium (see 

 below). New fellows and members will be elected at the General Assembly. 

 Information as to the election of new members, as well as the latest list of 

 Fellows and Members, may be found in the seventh issue, 1957, p. 207 — 210. 



In 1960 a Symposium will be held under the title: "Recent advances (since 

 19-i5) in our knowledge of germ cells and earliest stages of development". 

 Participation will probably be on the basis of introduction by fellows or mem- 

 bers. Most of the contributions will be of a comparative and synthetic nature. 

 The best possible chances will be given to young scientists, who have derived 

 some reputation from recent original achievements. 



There will be no division into sections. The tentative programme reads as 

 follows: 



1st Part: Formation, ultra-structure and physiology of oocytes, as seen in 

 the light of their morphogenetical significance (a) relations with the maternal 

 organism, b) progressive changes in structural and biochemical composition, 

 c) polarity and bilateral symmetry, d) nucleo-cytoplasmic relations, etc.). 

 As an addition, two supplementary evening lectures may be planned, dealing 

 respectively with the ultra-structure of the sperm cell, and with the biochem- 

 istry and physiology of the male gamete. 



2nd Part: Progressii^e maturation of the organization pattern in fertilized 

 and cleaving eggs (structure and biochemistry, type of cleavage, development 

 of symmetry, role of the nucleus, changes in the cortex, significance of the 

 respective blastomeres. topogcnesis and topochemistry, early development of 

 enzyme systems). 



Division to be made partly according to taxonomic groups, partly according 

 to more general themes. 



Separate reports are expected on: a) Spiralia, b) Arthropodes, c) Echino- 

 derms. d) Ascidians, e) development of symmetry in Vertebrates, f) role of 

 the nucleus, g) topogenesis and topochemistry, h) early development of 

 enzyme systems, i) Mammalia. 



