b. Mitotic rhythm in reduced weight (weight below water) during cleavage. 

 Psammechinus microtuberculatus (Echinoidea) (in collaboration with 

 W. L. M. GEILENKIRCHEN. Utrecht) 



c. Synchronization of cell division in mass cultures of various cell types, 

 by control of environmental factors. Tetrahymena pyriformis (Holotri- 

 cha, Ciliata) 



ZOTIN, A. I. Cand. Biol. Sci. — Inst, of Animal Morphol. "A. N. Severt- 



sov" 'of the Acad, of Sci. of the U.S.S.R., B. Kaloezjskaja oel., d. 33, 



MOSKOU. Russia 

 a. Study of the water content of embryos. Acipenser steliatus Pallas, A. 



giildenstadti Brandt, Huso huso (Acipenseriformes, Teleostei): Salmo 



salar morpha sebago Girard, Coregonus lavaretus baeri natio swirensis 



Pravdin (Clupeiformes, Salmonidae, Teleostei) 

 ZOUTEWELLE, W. B.Sc. — Zool. Lab. der Rijks Univ.. Janskerkhof 3, 



UTRECHT. Holland 

 a. Influence of various kations on development. Limnaea stagnalis (Gastro- 

 poda) (in collaboration with W. L. M. GEILENKIRCHEN and Chr. P. 



RAVEN) 

 ZUCCARELLO— POLLICITA, Mrs M. Dr — 1st. di Zool., Via Archi- 



rafi 18, PALERMO, Italia 

 a. The action of xenoplastic embryo extracts on explants. (Amphibia) 

 ZUCKERMAN, S. M.A., M.D., D.Sc, M.R.C.S., L.R.C.P., F.R.S., Prof. 



— Dept of Anat., The Med. School, Birmingham Univ., Edgbaston, 



BIRMINGHAM 1, England (U.K.) 



(no embryological work in progress) 

 ZWEIBAUM, J. Dr, Prof. — Inst, of Histol. and Embryol., Acad, of Med., 



ul. Chalubinskiego 5, WARSZAWA, Poland 



(no embryological work in progress) 

 ZWILLING, E. Ph.D. — Dept of Anim. Genet., Coll. of Agric, Univ. of 



Connecticut, Storrs Agric. Exper. Stat., STORRS, Conn., U.S.A. 



a. Disaggregation and reaggregation of early embryos. Effects on differen- 

 tiation. Gallus domesticus (Aves) 



b. Culture behavior of early embryonic tissues. Gallus domesticus (Aves) 



c. Ectoderm-mesoderm interaction in limb development. Gallus domesticus 

 (Aves) 



113 



