EVOLUTION. 
Gen. Sub. 56 
which the individual pupa is exposed. In Ohrysophanus phlceas the 
principal effects on colour are produced not by long exposure to severe 
cold, but by exposure, during the active pupal changes, to great heat 
(producing duskiness) or moderate cold (producing vividness of colour, 
smallness of spots, enlargement of copper band on hindwings) ; Merri- 
FIELD (345). 
Temperature of water, and number of vertebras in fishes; Jordan 
(272, 273). 
Effects of cold on organisms : Freshwater fishes survived being frozen 
at — 8 Q to -15° 0. Frogs survived, —28° ; centipedes, —50° ; a snail, 
— 120°; frog ova, -G0° ; Rotifers and Infusorians, —60°. Exposure 
to about —200° in liquefied air did not kill either germs or seeds. 
At —100° chemical processes cease ; much more so in seeds, germs, and 
spores subjected to — 200°. Yet many revived. Life is one of the con- 
stant forces of nature. It does not die as long as the structure in which 
it manifests itself is intact ; Pictet (398). 
Effect of cold on ova of Ascarit ; Sala (447). 
Transpiration and respiration in relation to the environment ; Dissart 
(130). 
Concentration of sea-water, its influence on activity of the heart. 
Increased concentration and consequent reduction in the amount of water 
in the cells lessens number of heart-beats, and vice versa ; Schively (460). 
Toxicity of water, according to Nageli ; Yarigny (512). 
Rudimentary eyes ; Kohl (294). 
Influence of function : morphological changes associated with the 
squatting posture ; Charles (97). 
Geotropism ; Jensen (271). — Heliotropism ; Loeb (319). 
Refer also to many researches under heading Experimental Embry- 
ology ; e.g., Driescii (135), Herbst (233). 
d. Elimination , Selection , and Isolation . 
Inadequacy of natural selection; Spencer (482). 
Sufficiency of natural selection ; Weismann (538). 
Discussion of natural selection, isolation, &c. Definiteness of varia- 
tion. Elimination the fact rather than selection ; Emery (147). 
Emphasis on “ constitutional selection,” i.e., in the process of natural 
elimination those forms with less suitable constitutions go to the wall. 
Speculative suggestions as to origin of Mammalian characteristics ; 
Haacke (204). 
Natural selection and Lamarckism ; Ball (17). 
Nutritive relations of Lepidoptera , interesting in connection with 
struggle for existence ; Seitz (469). 
Secondary sexual characters : possibility of sexual characters granted 
in case of certain birds. But in polygamous birds, the females belong to 
the victor among rival males, and some of these birds are brightly 
adorned. Colour may be an index of male vigour, but this does not 
