URBAN, P. Ph.D. — Dept. of Biol. Sci., Union College, SCHENECTADY, N.Y. 12308, 



U.S.A. 

 a Fine structure of gametogenesis, fertilization and early development. Bcyopsis hypnoides 



(Chlorophyceae) 

 URBANI, E. Prof. — 1st. di Istol. ed Embriol., Univ. di Roma, Citta Universitaria, 00185 



ROMA, Italy • 



URSPRUNG, H. Ph.D., Prof. — Lab. for Developm. Biol., Swiss Fed. Inst, of Technol., 



Sonneggstr. 5. 8006 ZURICH, Switzerland • 



a Biochemistry of differentiation. Drosophila melanogaster (Dipteca), Mus musculus (Roden- 



tia) 

 b Organization of imaginal discs. Drosophila melanogaster (Diptera) 

 UYSAL, M. M.D. — Inst, of Histol. and Embryol., Med. Fac, Hacettepe Sci. Center, 



ANKARA. Turkey 

 a Collagenogenesis in the umbilical cord. Homo sapiens (Primates) 

 VACEK, Z. MUDr., D.Sc, Prof. — Inst, of Embryol., Charles Univ., Albertov 4. PRAGUE 



2, Czechoslovakia 

 a Electron microscopy and histochemistry of the placenta (comparative studies on the sub- 

 microscopic structure, enzyme histochemistry and transport mechanism). Homo sapiens 



(Primates), (Rodentia; Carnivora; Insectivora; Chicoptera) 

 b Role of primitive streak and tail region in early differentiation of the body (submicroscopic 



and cytochemical studies in normal and experimental conditions). Rana esculenta (Anura), 



G -alius domesticus (Aves), Mus rattus (Rodentia) 

 VACQUIER, V. D. Ph.D. — Dept. of Marine Biol., Scripps Inst, of Oceanography, LA 



JOLLA, Calif. 92037, U.S.A. 

 a Control of enzyme synthesis during larval development, differentiation of the digestive 



tract. Dendtastet excentricus. Strong ylocenfrotus purpuratus (Echinoidea) 

 b Biochemistry of fertilization with emphasis on the role of beta-l,3-glucanohydrolase and 



other enzymes. (Echinoidea) 

 c Mechanisms involved in the physical interactions of blastomeres during cleavage. 



(Echinoidea) 

 VAHS. W. Dr.phil., Prof. — Zool. Inst, der Univ., Weyertal 119, 5 KOLN 41, W.Germany 

 a Quantitative cytochemistry of nucleic acids and proteins during induction and differentia- 

 tion. (Teleostei, Urodela; Aves) 

 b Phase specific gene activities in the eyecup-lens-system of the developing embryo, as 



revealed by quantitative cytochemical DNA determinations. Salmo irideus (Teleostei), 



(Urodela; Aves) 

 c Ultrastructure of embryonic cells undergoing induction and differentiation. (Urodela) 

 VAKAET, L. C. A. M.D., Prof. — Lab. of Anat. and Embryol., State Univ. Center, 



Groenenborgerlaan 171, 2020 ANTWERPEN, Belgium • 



a Early development. Gallus domesticus, Coturnix japonica (Aves) 

 b Fetal and neonatal endocrinology. Mus musculus albinus (Rodentia) 



c In vitro culture of blastoderms, normal and after experimental interventions: histo- 

 chemistry: enzymes and mucopolysaccharides. Coturnix japonica, Gallus domesticus (Aves) 

 d Autoradiography of oogenesis. Mus musculus (Rodentia) 

 VALDEZ de MORENO, Mrs. C. L. — Inst, de Biol, Univ. Nac. de Tucuman, Chacabuco 



461, S. M. de TUCUMAN. Argentina 

 a Anaerobiosis in oocytes. Bufo arenarum (Anura) 

 VANABLE. J- W., Jr. Ph.D. — Dept. of Biol. Sci., Purdue Univ.. LAFAYETTE. Ind. 



47907, U.S.A. 

 a The possibility of selectivity in neuromuscular associations: 1. extrinsic ocular muscles. 



Xenopus laevis (Anura); 2. muscles of coxa and leg. Periplaneta americana (Blattaciae) 

 VAN ALTEN, P. J. Ph.D., Prof. — Dept. of Anat., Coll. of Med.. Univ. of Illinois, 1853 



W.Polk St., P.O.Box 6998, CHICAGO. 111. 60680, U.S.A. 

 a Ontogeny of the immunological mechanism. Gallus domesticus (Aves) 

 b Development of lymphocyte competence to respond to mitogens in v i t ro. Gallus 



domesticus (Aves), Rattus norvegicus (Rodentia) 

 c Development of antigenic components in the brain. Mesocricetus auratus (Rodentia) 

 d Isotope studies of blood cell formation, especially lymphocytopoiesis. Gallus domesticus 



(Aves) 

 VANDEBROEK, G. D.Sc, Prof. — Lab. d'Embryol., Inst, de Zool., Univ. de Louvain, 59 



rue de Namur, LOUVAIN, Belgium • 



VAN DETH, J. H. M. G. M.D. — Dept. of Anat. and Histol., Univ. of Adelaide, ADE- 

 LAIDE, S.Austr. 5000, Australia 

 a Teratogenesis by hormones. Gallus domesticus (Aves), Rattus norvegicus (Rodentia) 

 b Hormonal influences on sex determination. Gallus domesticus (Aves) 

 VAN GANSEN (RASMONT), Mrs. P. Prof. — Lab. de Cytol. et Embryol. Molec, Univ. 



libre de Bruxelles, 67, rue des Chevaux, 1640 RHODE-ST-GENfiSE, Belgium • 



a Ultrastructure of young ovaries at metamorphosis. Xenopus laevis (Anura) 

 b Development of germ cells from oogonia up till mature oocytes (electron microscopy), 



especially nucleolar structures at the beginning of meiosis. Xenopus laevis (Anura) 



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