PIRIA. F. — Cattedra di Istol. ed Embriol. gener., Fac. di Med. e Chir. 



dcll'Univ. di Milano. Via Ponzio 7, MILANO, Italia 

 a. Histochemical observations and paper electrophoresis on the ground sub- 

 stance of the umbilical cord. Homo sapiens (Primates) (in collaboration 



with Mrs. V. PRETO PARVIS) 

 PLESNER P. M.D. — Biol. Inst, of the Carlsberg Foundation, 16, Ta- 



gensvej, COPENHAGEN N., Denmark 

 a. Studies on the biochemistry and physiology of synchronized cell systems. 



Tetrahymena pyrifovmis (Holotricha, Ciliata) (in collaboration with 



K. HAMBURGER and E. ZEUTHEN) 

 PLETZEN, R. van D.Sc. — Dept. of Zool.. Univ. of O.F.S., BLOEM- 



FONTEIN. South Africa 



(no embryological work in progress) 

 PLUTA, E. Mgr. — Chair of Gener. Biol., Silesian Acad, of Med., Rokit- 



nica, ZABRZE 8, Poland 



a. Regeneration of the thyroid gland after experimental injury. 



b. Physiological restoration of the thyroid gland. 



POHLEY H.-J. Dr. — Inst, fur Entwicklungsphysiologie, Univ. zu Koln, 

 Gyrhofstr. 17, KoLN-LINDENTHAL, Deutschland 



a. Entwicklung der Fliigel. Regeneration und Superregeneration der Fliigel- 

 anlagen. Einwirkung der regenerierenden Anlagen auf den Zeitpunkt der 

 Puppenhautung. Ephestia kiihniella (Lepidoptera) 



b. Einfluss der Antennenlange auf die Dauer der Larvenstadien. Peripla- 

 neta amevicana (Orthoptera) 



POLEZHAEV, L. V. Dr. Biol. Sci., F.I.I.E., Prof. — Inst, of Animal 

 Morphol. of the Acad, of Sci. of the U.S.S.R., Lenin Avenue 33, 

 MOSCOW V-71, U.S.S.R. 



a. Regeneration of cranium bones. Mas domesticus, Rattus norvegicus, 

 Oryctolagus cuniculus, Felis domestica, Canis familiaris (Mammalia) 



b. Regenerative capacity and immunity in ontogenesis. Rana lempotavia, 

 Bombina bombina (Anura) 



c. Regeneration of brain. Felis domestica, Canis familiaris, Rattus norvegi- 

 cus (Mammalia) 



d. Regeneration of myocardium. Rattus norvegicus, Oryctolagus cuniculus, 

 Felis domestica (Mammalia) 



e. Regeneration of dental tissue. Canis familiaris (Carnivora) 



POPOV, V. V., Dr., Prof. — Dept. of Embryol, Moscow State Univ., 



MOSCOW, U.S.S.R. 

 POPP, R. A. Ph.D. — Biol. Div., Oak Ridge National Lab., P.O. Box Y, 



OAK RIDGE, Tenn., U.S.A. 

 a. Red blood cell lineage during embryonic development. Mus musculus 



(Rodentia) 

 PORTMANN, A. Dr.Phil., Prof. — Zool. Anstalt der Univ., Rheinsprung 



9, BASEL, Schweiz 



a. Embryology and postembryonic development. (Araneida) 



b. Embryology of the forebrain (including postembryonic stages). (Aves; 

 Mammalia) 



c. Development of skin pattern. (Reptilia) 



d. Development. (Opisthobranchia, Gastropoda) 



e. General embryology. Octopus spec. (Cephalopoda) 



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