contains a map of Bologna in the 17th century. There is an analytical index 

 of 137 pages, and a bibliography of more than 2,000 titles. 



2 SEX DETERMINATION 



1966 



by G. Bacci Pergamon Press 



International Series of Monographs Oxford etc. 



on pure and applied Biology Price: 84 s, 

 313 pp.. 87 figs., 3 pis., 5 tbs. 



This is a really exhaustive monograph on the subject of sex determination 

 and parthenogenesis, written on a comparative basis, and comprising the 

 whole animal and plant kingdom including the unicellular and acellular 

 organisms. The contents are largely of a genetical and general-biological 

 nature, and only one of the 12 chapters deals with phenomena of phenotypic 

 sex differentiation, as opposed to genetic or environmental sex determination. 



It is impossible to review the book extensively. The only chapters which 

 have a clear bearing on developmental problems are the first two, which 

 discuss sexual and asexual reproduction, and reproductive cycles, respectively 

 (together 46 pp.)- and chapter 9, entitled "Sex genotype and sex phenotype" 

 (21 pp.). The discussion in the latter chapter is restricted to sex differentiation 

 in amphibians and crustaceans, and clearly is only a corrollary to the main 

 subject of the book. The author stresses the fact that the most varied ex- 

 pressions of sexuality may conceal similar genetic sex-determining mechanisms, 

 and, conversely, that quite similar sex phenotypes may be attained through 

 different genetic mechanisms. 



The book is well-produced and well-illustrated. It contains a bibliography 

 of 27 pages and a glossary, and is concluded by a combined taxonomic and 

 subject index. 



3 SIZE AND CYCLE 



1965 

 by J. T. Bonner Princeton University Press 



227 pp., 24 figs.. 30 pis., 2 tbs. Princeton, N.J. 



Price: $ 7.50 



The nature of this essay is largely theoretical. The author presents a new 

 way of looking at the whole of the science of biology, and attempts to formulate 

 concepts that bring together molecular, developmental, and evolutionary events 

 into one unifying perspective. He takes the life cycle as the essential unit of 

 the living world, rather than the organism at a particular moment in time. 

 While the life cycle, composed of a series of specific chemical reactions 

 ("steps"), represents the qualitative aspect of living things, the complementary 

 quantitative aspect is represented by size (the number of "steps"); the role of 

 the latter in evolutionary adaptation is stressed in particular. 



After a brief introductory chapter and a chapter describing the method 

 underlying the essay, there follow three major chapters. The first of these 

 deals with the changes in size encountered in a variety of life cycles. The 

 next chapter discusses in a general way what is known about the "steps" 

 that constitute life cycles. This involves discussions of gene action, environ- 

 mental stimuli, the various modalities of division of labour (differentiation), 

 and the integration of steps. The last chapter then deals with the applications 

 of the principles hitherto discussed to the problem of evolution. The book is 

 rounded off by a brief conclusion. 



The author illustrates his concepts with a wealth of morphological, ecolo- 



270 



