The main feature of the book is the classification of the subject matter under 

 a number of specific "routes of development", which are characterized by the 

 operation or non-operation, either singly or in combination, of four cytological 

 variables: 1. suppression of the first polar body; 2. of the second polar body; 

 3. of the first cleavage division; 4. genetic absence of spermatozoa. The author 

 thus distinguishes a major group of sixteen routes of development (eight apo- 

 mictic - parthenogenetic, and eight amphimictic routes), and a minor group 

 of some ten routes, which are less well understood. 



The introductory chapter gives an outline of eutherian development, and 

 furthermore contains the necessary terminological definitions as well as basic 

 information regarding chromosome preparations and chromosome counting. 

 The concluding chapters discuss a variety of subjects, among which are e.g. 

 polyploid evolution in mammals; viability of polyploid mammals; genetic con- 

 trol, sex determination, fertility and growth in parthenogenones and polyploids. 



Typographically the book has received the same care as preceding numbers 

 of the series. 



"LE MACROMOLECOLE DEI VIVENTI" 

 1955 



Congress Report Rendiconti dell* 1st. 



Convegno Antonio Baselli Lomb. di Sci. e Lettere a Milano, 

 Pallanza. July. 1955 CI. di Sci., Vol. 89 



(22 contributors) Price: $ 5. — 



348 pp. 



This book represents a report on a Congress on biological macromolecules, 

 held in Italy during 1955. It is in the form of a series of papers. Of the 22 

 contributors, 8 are from Italy, 7 from the U.S.A., 4 from England and 3 from 

 other Western-European countries. The contributions are written in English 

 (9), Italian (5), French (2) and German (1). The Italian papers are preceded 

 by a summary in English, all other papers by an italian summary. 



The two papers concerned directly with embryonic stages are entitled: ,,Le 

 macromolecole nella determinazione embrionale" (by S. Ranzi, 24 pp.) and ,,La 

 lipovitellina dell'uovo di polio" (by G. Lanzavecchia, 20 pp.). 



The book is concluded by author and subject indexes. 



"GESTATION" 



Conference Trans. 1954—1956 



edited by L. B. Flexner (1st Conf., The Josiah Macy, Jr Foundation, 



1954) and C. A. Villee (2nd & 3rd Conf., New York 



1955 and 1956) Price: 1st Conf. $ 5.— 



Total no. of pp. 720, figs 304, tabs 45 2nd Conf. $ 5.— 



3rd Conf. $ 4.75 



The Conferences reported on here are part of the Conference Programme of 

 the Josiah Macy, Jr Foundation. This consists of a number of small groups of 

 scientists in medicine and allied disciplines, mainly from the U.S.A.. who meet 

 annually for a period of five or more years. 



At present the first three reports of the gestation group are available in the 



216 



