Yiii CALIFORNIA ACADEMY OF SCIENCES. 



NORMAL TRANSMISSIONS: observed instances of change due to environ- 

 ment, 34; examples of changes in goldfish and brine-shrimp, 34-35; 

 discussion of the validity of these examples as proofs, 35; after 

 effects in plants illustrative of an hereditary rhythm, 36; change 

 in environment not established in one generation, but only the 

 predisposition to change, 37; inheritance of acquired habits, 38; 

 Elliott's examples, 38; these not proofs of inheritance, 39; Dar- 

 win's instances criticised by Ball, 40; results which can be best 

 explained by transmission of acquired characters, 41; Eomanes' 

 examples of instinct due to the transmission of acquired charac- 

 ters, 41-42; aesthetic faculties of man, 42; Spencer's three forms 

 of evidence of transmission, 43; the first and third form untenable, 

 according to Romanes and Ball, 43-44; correlation as a proof, 44; 

 the giraffe as an illustration of correlation, 44; Ball's criticism of 

 this illustration, 45; further discussion of correlation, 46; Osborn 

 on paleontological proofs of transmission, 46-48; Poulton's reply 

 to Osborn's evidencs, 48; summary of discussion, 49-50. 



VARIATION AND NATURAL SELECTION 50 



Scope and meaning of natural selection, 51; not creative (Schur- 

 man), 51; conditioned by variation, 52; variations quantitative 

 rather than qualitative, 52; how are new parts originated?, 53; 

 variations must be advantageous to Jbe favored by selection, 53; 

 Romanes on useless variations favored by selection, 54. 



THEORIES EXPLAINING VARIATION 54 



Spencer's physiological units, 55; "Weismann on sexual combina- 

 tions, 55; variations according to this view must be within the ex- 

 tremes of ancestral modification, 55; Hartog's objection, 56; Lloyd 

 Morgan's theory of organic compounds, 58; objections to this 

 view, 59; Three views of the origin of variations, 59; spontaneous, 

 uninfluenced by environment, 59; due solely to environment, 60; 

 inherent tendency to vary in a specific direction, 60; conservative 

 variations, 61; progressive variations, 61; Brooks' secondary 

 laws of variation, 62; conclusion concerning variations, 62. 



LAWS CONDITIONING EVOLUTION 64 



LAWS OF DEVELOPMENT 65 



Bathmism, or growth force, 65; law of extent and density; 66; 

 phylogenic extent and density, 67; metabolism, 67; law of sexual 

 t intensification, 68; Gulick's criticism of Brooks' theory of male 

 progressiveness, 72; acceleration and retardation, 73; cause of ac- 

 celeration, 74; the originator of the fittest, 75; bearing of the law of 

 phylogenic extent and density upon acceleration and retardation, 

 76; law of concentration, 77. 



LAWS or STRUCTURE 77 



Homology, 77; successional relation, 77; parallelism, 78; adapta- 

 tion, 78; geratology, 78; bilateral symmetry, 79; correlation of 

 growth, 79. 



