INDEX 



241 



Specialization : meaning of term, 

 36 ; law of, with animals, 35-41 ; 

 law of, with plants, 67-71. 



Species, systematic, definition of, 1. 



Specific constancy, theory of : 

 supporting points, 4 ; not estab- 

 lished in its original sense, 164- 

 228. 



Spontaneous Generation. See Gen- 

 eration. 



Steinmann, G., 29, 31 ff., 47, 66, 

 138, 230 f. 



Strasburger, Noll, Schenk, and 

 Schimper, textbook of, 91, 112. 



Symbiotics (symbiosis) : definition, 

 177 f. ; recognizable as ' adapted ' 

 forms, 188-202 ; symbiosis leads 

 up to the formation of new 

 families, 189, 193, 202. 



Systematic classification : system- 

 atic categories, 1 f . ; the higher 

 categories (stocks, classes, orders) 

 show no genetic connection 

 according to palseontological 

 research, 33, 48 f., 62 ff., 75; 

 principles of, 117-129 ; the 

 higher categories at least are 

 primary grades of perfection, 

 131, 136 f., 229. 



TAPEWORMS, examples of graduated 



retrogression, 183 ff. 

 Termitophils. See Myrmecophils. 

 Transitional forms, phylogenetic 

 intermediate) forms : Stego- 



cephali, 31 ; of the insects, 37 f. ; 



in plants (Pteridosperms), 58, 63 ; 



general principles for deciding 



apparent intermediate forms, 

 130 ff. 



Types : meaning in systematic 

 classification, 117 ; description 

 of the generally accepted types 

 of the animal and plant kingdoms, 

 118-129 ; actual number of, 137 ; 

 a type is always a constantly 

 maintained grade of perfection, 

 137 f., 229. 



VARIABILITY of organisms through 

 the direct influence of the life 

 conditions, 164-168; kind of 

 variation, 168 ff. ; by isolation 

 and in-breeding, 170177 ; by 

 the influence of changed modes 

 of life, 178-228. 



Vertebrates : lacking in the Cam- 

 brian formation, 23 ; first ap- 

 pearance in the Silurian, 27 ; 

 succession of the classes, 28 ; no 

 connection between the different 

 classes, 31 ff. ; systematic classi- 

 fication, 119. 



Verworn, M., 92. 



WAGNER, A., 147, 148, 150, 151, 



152, 154, 155, 156, 231 f. 

 Walther, J., 43. 



Warnung, E., 73, 122-128, 135, 136. 

 Wasmann, E., 4, 41, 87, 115, 116, 



188, 189, 202, 214. 

 Weismann, A., 163, 170. 

 Wilson, E. B., 98, 100. 



ZITTEL, K., 7, 53, 54, 68, 225. 



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