form of three neatly printed and bound books, with a great number of good 

 illustrations. The books contain a total of 22 contributions followed by group 

 discussions. Most of these are concerned with the placenta, but some deal 

 with such subjects as lactation, implantation, fetal circulation, fetal growth, 

 fetal endocrine glands and sex differentiation. Each contribution is followed 

 by a reference list, and each book contains an extensive index. 



"DIE SEXUALITAT" 

 2nd revised edition, 1956 



by M. Hartmann Gustav Fischer Verlag, Stuttgart 



463 pp. with 288 figs Price: D.M. 54.— 



The first edition of this book appeared in 1943. The book is dedicated to 

 C. Correns, and is based to a great extent on Correns' theories of sexuality. 

 The subject matter is divided into four parts, a division based on the one hand 

 on the distinction between genotypical (chromosomal) and "phenotypical" 

 (non-chromosomal) sex determination, and on the other hand on the phase 

 (haploid or diploid) during which sex determination takes place. The book is 

 concluded by chapters on general sex theory and general theory of fertilization. 



The general plan and the theoretical basis have not been changed in this new 

 edition. Of course much new material has been incorporated, but some of the 

 older theoretical matter that has been disproved in the meantime, has been 

 omitted. The chapter on diplo-genotypical sex determination (chromosomal sex 

 determination during the diploid phase, occurring in nearly all vertebrates) 

 has been rewritten and considerably extended. In particular a separate section 

 has been devoted to the developmental-physiological basis of this type of sex 

 determination. 



The number of illustrations has been increased from 245 to 288, and most 

 of the old figures have been redrawn. 



"THE AMERICAN ARBACIA AND OTHER SEA URCHINS" 



1956 



by Ethel Browne Harvey Princeton University Press 



298 pp. with 12 text figs and (lay-out by G. J. Thieme, N.V., 



16 pis (245 photogr.) Nijmegen, Netherlands) 



Price: $ 6. — 



The present book is unusual both in form and content. It deals almost ex- 

 clusively with one species, Arbacia punctulata, viewed from many different 

 angles. 



The book is composed of four parts. The first of these deals with the subjects 

 of natural history, sex, breeding and classification, but besides this supplies 

 interesting information on such varied subjects as etymology, historical des- 

 criptions, fossils and the use of sea urchins as food and medicine. 



Parts two and three deal respectively with normal development and with 

 egg centrifugation experiments. The chapters on normal development give 

 equal attention to morphology and physiology. Clear diagrams have been 

 added of the arrangement of membranes and layers before and after fertiliza- 

 tion, according to Harvey and Dan. A special chapter is devoted to the sperm. 



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