ILLUSTRATIONS. 



Plate I. Iberian tj'pe (original); Spaniard from Madrid (photograplis by Martin) . 

 II. Celt (Kelt of Britain) type; from North Carolina (photographs by 

 Martin). 



III. Littoral type (modified) ; Indian Sikli from the Himalaya Mountains 



(photographs by Martin) . 



IV. Celt-Iberian type; from Wisconsin (photographs by Martin). 

 V. Celt and Iberian types (photographs by Martin). 



VI. Celt-Iberian and Iberian types (photograplis by Martin). 

 VII. Iberian from Madrid, Spain, and modified Littoral from the Himalaya 

 Mounutains (northern India) (photographs by Martin) . 



Page. 

 Fig. 1. (In the text.) Efl'ects of crossing white and black guinea pigs 221 



2. (In the text.) Segregation of the sex cells in the segmentations 



of the ovum after fertilization 222 



3. (In the text.) Chromosomes as conceived by Weissmann 223 



4. (In the text.) Germ cells as considered by Adami 223 



5. (In the text.) Germ cell after fusion 224 



233 



