Pflugfelder 71 Pletzen 



b. Tumorentstehung nach Storung des Hormonhaushalts. (Evertebrata und 

 Vertebrata) 



c. Wachstum und Differenzierung der Ganglienzellen des Mesencephalon 

 von Verre6raren nach Exstirpation der Augen. 



PHILLIPS, R. J. S. B.Sc. — Med. Res. Council. Inst, of Anim. Genet., 

 West Mains Rd, King's Buildings, EDINBURGH 9, U.K. 

 a. Developmental study of a new fifth-toe Polydactyly character in Mus 

 musculus. (Mammalia) 



PIATT, J. A.B., M.A., Ph.D., Assoc. Prof. — Dept of Anat., Univ. of 

 Pennsylvania, School of Med., PHILADELPHIA 4, Pa, U.S.A. 



a. Transplantation of brachial cord segments in Amblystoma punctatum 

 embryos. With a view to analyzing the factors responsible for normal 

 cord structure and function; i.e. is continuity of neural axis necessary 

 for the normal form and function of specific parts? (Amphibia) 



b. Survey of the motor regions of the brain of Amblystoma. With a view 

 to a morphological and functional separation of each. (Amphibia) 



PIEPHO, H. Dr Phil., Prof. — Zool. Inst, der Univ. Gottingen, Mathem.- 

 Naturw. Fak., Nicolausbergerweg 75, GOTTINGEN, Deutschland. 

 a. Metamorphose der Insekten. 



PINCUS, G. Dr, Prof. — Tufts Coll., Med. School and Worcester Foun- 

 dation for Exper. Biol., 222, Maple Ave, SHREWSBURY, Mass., 

 U.S.A. (no data received) 



PIOTROWSKA, J. — Inst, of Histol. and Embryol., Med. Acad., GDANSK, 

 Poland, 

 a. The ultraviolet influence on eggs under various experimental conditions. 

 Rana temporaria (Amphibia) 



PISANO, A. Dr Biol.Sc. — Inst, de Zool., Univ. Nac. de Tucuman, Miguel 

 Lillo 205, TUCUMAN, Argentien, S. America. 



a. Parabiosis between pure breed and hybrid Urodela. Triturus cristatus 

 and T. vulgaris 



b. El desarrollo del Telmatobius schreiteri. (Anfibio, Anuvo) 



c. Trasplantos cruzados de regiones ectodermicas entre larvas de distinctas 

 formas geneticas de Leptodactylus ocellatus. (Anfibio, Anuro) 



d. Fecundacion cruzada entre Telmatobius schreiteri e Hyla raddiana. 

 (Anfibio, Anuro) 



CASTIGLI PITOTTI, Mrs M. Dott. — 1st. di Biol, gen., Fac. di Med., 

 S. Pietro, PERUGIA, Italia. 



a. Natura della gastrulazione senza segmentazione. Petromyzon fluviatilis 



b. Azioni e reazioni nella metamorfosi degli Anfibi. Bufo vulgaris 



c. Fermenti embrionali. Petromyzon (Ciclostomi) 



PLANQUE, B. de — Hubrecht Lab., Internat. Embryol. Inst., Janskerkhof 2, 



UTRECHT, Holland, 

 a. Regulation potencies in the neural plate. Formation of neural crest by 



regulation after implantation of young neural plate tissue in the ventral 



side of neurulae, or by homogenetic induction after implantation in middle 



gastrulae (heteroplastic transplantation). Triturus taeniatus, alpestris 



and cristatus (Amphibia) 

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



FONTEIN, South Africa, (stud, of Sool. Inst., STELLENBOSCH) 

 a. Ontogenesis and morphogenesis of the breast-shoulder apparatus (and 



of skeletogenous strata). Xenopus laevis (Anura, Amphibia) 



