Contents xxvii 



mentalism, 305. This due particularly to discovery of inter- 

 dependence between adult characters and chromosomes of 

 germ-cells, 30C. Revised conception of heredity essential to 

 interpreting thin interdependence, 307. Unwarrantable tend- 

 ency to restrict heredity to sexual propagation, 308. Unwar- 

 rantable tendency to restrict heredity to adult characters, 811. 

 Importance of recognizing heredity as working by transforma- 

 tion rather than by transmission, 312. Tendency to confuse 

 hi-n-ililif irith riiimt'it of heredity, 313. Definition of heredity 

 adopted iii (hi* discussion, with remarks on its application to 

 flic chromosome theori/, -U ',. Meaning >id criterion of "mech- 

 anism of heredity," .:.'.'. 



XII. KVIDEXCE FAVORABLE TO CHROMATIX AS HEREDITARY SUB- 



STANCE 3?H 



A. Direct Evidence. Evidence from tin ontogeny of some ' 

 protozoans, 326. Evidence from certain cells of multicellular 

 organisms, 331. Evidence from gpennatozoan. .133. Evidence 

 from pigment cells, 333. B. Indirect I'lridcnce, 341. The 

 chromosomes of germ-cells in fertilization, !'/.'. Fertilization 

 of the ova of one species by the sperm of another species, 344- 

 The connection of sex with a particular chromosome, 346. The 

 connection of mutations with particular chromosomes, 353. 

 Chromosomes and the Mendelian mode of inheritance, 356. 



XIII. KVIDEXCE FROM PROTOZOANS TlIAT SUBSTANCES OTHER TlTAN 



CHROMATIS- ARE PHYSICAL BASES OF HEREDITY . . . 363 

 Evidence from the ontogeny of various protozoans, 363: (a) 

 Stentor. .sn.:; (l>) \Vh<it s/ndi/ of the ontogeny of Diplodinwm 

 trill i>rol><il>l</ discover, 370; (c) The origin of ftagella, 370; 

 (d) 1'nrioux organs of XI ylonychia and I'aramecinm, 373; () 

 The skeleton of radlolaria, 375; (f) Openings in the central 

 ca/tfiiite of the rudiolaria, 379; (g) The shells of foraminifera, 

 385; (h) The din gin <i organ* of tt^orozoa, JM1 ; (j) The "di- 

 ri.xion center" of .\odilnca, 390 i (j) The centrosphere of pro- 

 tozoa generally, M)//. Concluding remark on the evidence pre- 

 sented, 397. 



