60 Gen . Sub. 
I. GENERAL SUBJECTS. 
as containing the more fundamental causes of variation, and adds those 
of geographical isolation or segregation (Wagner and Gulick), the effects 
of gravity, the effect of currents of air and of water, of fixed or sedentary 
as opposed tb active modes of life, the results of strains and impacts 
(Ryder, Cope, and Osborn), the principle of change of function as 
inducing the formation of new structures (Dohrn), the effects of para- 
sitism, commensalism, and of symbiosis ; in short, the biological environ- 
ment ; together with geological extinction, natural and sexual selection, 
and hybridity Packard (402). 
Arguments against Lamarckian, and supporting Darwinian position ; 
Poulton (425). 
Criticism of Haacke’s Gemmaria-Theory; Lendenfeld (303). — Defence 
of Theory of Gemmaria ; Haacke (208). 
Functional “ Selbstgestaltung ” and modification of species in relation 
to its variable social environment ; Pfeffer (414, 415). 
Contributions to the mathematical theory of evolution : Pearson 
(409). 
Importance of migration and acclimatisation ; Below (31). 
Numerical intensity of faunas varies with environment, favourable to 
unfavourable, and with vitality, high to low. “ If the line of numerical 
decline for a species proceeds from changing environment, it will be, 
upon the Darwinian theory, accompanied by specific offshoots, and the 
disappearing species will sink from sight amidst the emergence of related 
species ; but if it proceeds from devitalisation it will display a species 
dying as it were alone.” . . . ; Gratacap (199). 
Periods in species-life. Hypotheses as to periods analogous to youth, 
growth, aud decrepitude ; Servier (508). 
Principles of Bioplastology ; Hyatt (254). 
The energy of evolution : a study of growth-energy or Bathmism ; 
Cope (99). 
Zoophyletic law : “ Universal ” joints preceded uni -functional joints, 
“ universal ” feet preceded those adapted for but one kind of movement. 
So animals adapted to a maximum of life-conditions preceded those 
adapted for only one. In short, progressive specialization of function ; 
Tornier (537). 
Convergence; Werner (569). — Convergence and poecilogony in insects; 
Giard (187). 
Correlations of volumes and surfaces : The changes of shape exhibited 
by organisms may be reduced to two categories, (1) indefinite stretching 
in linear directions, of which dichotomy is only a special form ; (2) 
indefinite flattening, compression, or attenuation of part or all the sub- 
stance into a flat plate or into laminae ; Ryder (473). 
Importance of prolonged dependent infancy in development of intelli- 
gence and social organisation ; Riley (454). 
Darwinism and race progress ; Haycraft (224). 
Conception of spocies as modified by the doctrine of evolution ; 
Britton (67). 
