SPECTOR, C. Ph.D. — Dept. of Biol., Univ. of Pittsburgh. PITTSBURGH, Pa. 15213, 



U.S.A. 

 a The possible control of development by differential biosynthesis of specific gibberellins. 



(Plantae) 

 SPENCER, R. P. M.D., Ph.D., Prof. — Dept. of Radiol., School of Med., Yale Univ., 333 



Cedar St., NEW HAVEN, Conn. 06510, U.S.A. 

 a Development of heart weight and blood volume. (Delphinoidea, Cetacea), (Mammalia) 

 h Development of kidney. (Mammalia) 



• SPERRY, R. W. Ph.D. — Div. of Biol., Calif. Inst, of Technol., PASADENA, Calif. 



91109, U.S.A. 

 SPIEGEL, Mrs. E. SCLUFER Ph.D. — Dept. of Biol. Sci., Dartmouth Coll.. HANOVER. 



N.H. 03755, U.S.A. 

 a Protein changes in development. Lytechinus pictus. Strong ylocentrotus purpuratus 



(Echinoidea), Rana pipiens, R. catesbeiana (Anura) (in collaboration with M. SPIEGEL) 

 b Role of enzyme induction in development. Rana pipiens, R. catesbeiana (Anura) (in 



collaboration with M. SPIEGEL) 

 c Biochemistry of metamorphosis. Rana pipiens, R. catesbeiana (Anura) 



• SPIEGEL, M. Ph.D., Prof. — Dept. of Biol. Sci., Dartmouth Coll., HANOVER, N.H. 



03755, U.S.A. 



a Protein changes in development. Arbacia punctulata. Lytechinus pictus. Strong ylocentro- 

 tus purpuratus (Echinoidea), Rana pipiens, R. catesbeiana (Anura) (in collaboration with 

 Mrs. E. SCLUFER-SPIEGEL) 



b Role of enzyme induction in development. Rana pipiens, R. catesbeiana (Anura) (in 

 collaboration with Mrs. E. SCLUFER-SPIEGEL) 



SPINNER, W. Dipl.phil. — Zool.-vergl. Anat. Inst., Naturwiss. Fak., Univ. Zoirich, Kiinst- 

 lergasse 16, 8006-ZuRICH, Schweiz 



a Determination and differentiation in cells of leg imaginal anlagen. Culex pipiens (Diptera) 



• SPIRITO, A. Dott., Prof. — 1st. di Biol, gener., Fac. di Med., Univ. di Roma, Viale di 



Porta Tiburtina 28, ROMA, Italia 

 a Origine e natura dei tumori. Bufo spec. (Anura) 

 b Trapianti xenoplastici negli embrioni. (Amphibia) 

 SPISAK (PtONKA), Mrs. I. M.Sc. — Dept. of Biol, and Embryol., Acad, of Med., ul. 



Kopernika 7, KRAKOW, Poland 

 SPOFFORD, W. R. Ph.D., Prof. — Dept. of Anat., School of Med.. State Univ. of New 



York. 766 Irving Ave.. SYRACUSE, N.Y. 13210, U.S.A. 

 a Induction and determination in the neural plate. Ambystoma maculatum (Urodela) 

 b Experimental neurogenesis. Ambystoma maculatum (Urodela) 



• SPRATT, N. T., Jr. Ph.D., Prof. — Dept. of Zool., Coll. of Biol. Scis., Univ. of Minnesota, 



MINNEAPOLIS, Minn. 55455. U.S.A. 

 a Investigating the nutrient requirements essential to morphogenesis and growth in the 



early stages of development (pre-streak and streak blastoderms). Gallus domesticus 



(Aves) 

 b Survey of dehydrogenase enzymes in early embryos. 1. Localization of enzyme activity. 



2. Structural integrity and enzyme activity. Gallus domesticus (Aves) 

 c Cytological study of the developmental center (organizer). Gallus domesticus (Aves) 

 d Analysis of mechanism of morphogenetic movements by time-lapse cinematography. Gallus 



domesticus (Aves) 

 e Analysis of dynamic population patterns (pattern formation by free-swimming, ciliated 



and flagellated organisms). Tetrahymena spec. Euglena spec. (Protozoa). Arbacia 



punctulata (Echinoidea) 

 f Integrative mechanisms in early development. (Aves) 

 g Role of the microenvironment in cell differentiation. (Aves) 

 SPRINGER, Ch. A. M.S. — Dept. of Entomol., 317 Frear Labs, Pennsylvania State Univ., 



UNIVERSITY PARK, Pa. 16802. U.S.A. 

 a Development of the neural elements in the central nervous system. Triatoma sp., Cimex sp. 



and other spp. (Hymenoptera) 

 SRB. v. — Dept. of Gen. Biol., Med. Fac, Charles Univ., Simkova 870, HRADEC KRA- 



LOVfi, Czechoslovakia 

 a Studies of chromosomes in the developing embryo; influence of ionizing radiation or 



chemomutagens on karyotype. Gallus gallus (Aves), Mus musculus (Rodentia) 

 SREBRO, Z. A. D.M. — Dept. of Biol, and Embryol.. Acad, of Med., ul. Kopernika 7, 



KRAK6W, Poland 

 STAAL, G. B. Dr., Ir. — Lab. of Entomol, Agricult. Univ., Binnenhaven 7, P.O.B. 62, 



WAGENINGEN, Netherlands 

 STACKHOUSE, H. L. Ph.D. — Dept. of Zool., Univ. of Toronto, TORONTO 5, Ont., 



Canada 

 a Some aspects of pteridine biosynthesis. (Amphibia) 

 STADLER, H. Cand.phil. — Div. of Cell Biol, and Chem. Embryol., Zool. Inst., Univ. of 



Bern, Sahlistr. 8, 3000 BERN, Switzerland 



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