CONTENTS. xi 



PAGE 



of acquired characters, 266. Great use could be made of 

 the Lamarckian factors in explaining evolution phenomena 

 if these factors could be given validity, 271. Orthogenesis 

 and determinate variation, pointing toward orthogenesis, 

 271. Nageli's theory of orthogenesis, 277. Eimer's ortho- 

 genetic theory, 282. Cope's theory of bathmism and 

 kinetogenesis, 285. Jaeckel's theory of metakinesis, 289. 



APPENDIX: References to Lamarck's writings, 290. Brown- 

 Sequard's experiments on guinea pigs, 290. Hyatt's 

 studies of Planorbts, 295. Fischer's experiments with 

 butterflies, 296. Experiments with silkworms, 298. Ref- 

 erences to books and papers on inheritance of acquired 

 characters, 305. Redfield's position, 305. Montgomery's 

 explanation of inheritance of variation, 306. Scientific 

 aspects of Burbank's work, 310. Orthogenetic variation 

 in palaeontology, 319. A case of apparent determinate 

 variation, 319. Pfeffer's theory of orthogenesis, 320. 

 Eimer's theory of orthogenesis, 321. Apparent determi- 

 nate evolution, 322. Snodgrass's observances on bills of 

 Galapagos birds, 323. Cope's belief in orthogenetic evolu- 

 tion, 323. Whitman's belief in determinate variation, 325. 

 Cunningham and orthogenesis, 326. 



CHAPTER XL 



OTHER THEORIES OF SPECIES-FORMING (Con- 

 tinned}; THEORIES ALTERNATIVE TO SELEC- 

 TION (Contented} 327 



Heterogenesis or the mutations theory, 327. Formula- 

 tions of heterogenesis theories by von Kolliker, Dall, 

 Galton, and Emery, 330. Korschinsky's heterogenesis 

 theory, 333. De Vries's mutations theory, 337. Present 

 status of de Vries's theory, 348. Alternative theories to 

 explain secondary sexual characters, 352. 



APPENDIX: Mendel and his work, 356. References to 

 recent work on Mendelism, 357. Darwin's examples of 

 race origin from sports, 357. A recent example of race 

 origin from a sport in cattle, 358. Galton's discussion of 

 specific stability, 360. References to discussions by de 

 Vries of species-forming, 362. American opinions of the 

 mutations theory, 362. Davenport's example of species 

 origin by slight continuous change, 367. Merriam's criti- 

 cism of the mutations theory, 367. Plate's criticism of the 



