PLATES AND TEXT-FIGURES 



xin 



PLATE To face 



XVI. Life-history of the Gall-fly Neuroterus . . . p. 136 



XVII. Hetero- and Idio-chromosomes in Hemiptera, 



from WILSON .... . p. 156 



XVIII. Chromosome-groups of Metapodius, from WILSON p. 160 

 XIX. Chromosome-cycle in Phyllaphis . . . . p. 163 



XX. Chromosomes in the development of eggs and 

 spermatozoa in Rhabdonema nigrovenosum, 

 after BOVERI p. 167 



XXI. Chromatin diminution in segmentation of the egg 



of Ascaris, after BOVERI . . . . p. 174 



XXII . Germ-cell determinant in segmenting egg of Sagitta, 



after ELPATIEWSKY. 

 Ectosomes in segmenting egg of Cyclops, after 



AMMA ........ p. 176 



XXIII. Segmentation of the egg of Miastor, after HEGNER p. 178 



XXIV. Development of Dentalium, showing effects of re- 



moval of yolk-lobe, from WILSON . . . p. 249 



TEXT-FIGURES 



Mitochondria in the spermatogenesis of Blaps, after 



DUESBERG ........ 



2. Golgi apparatus in epidermal cells, after DEINECKA 



FIG. 

 i. 



3- 



4 

 5- 



6. 



Equatorial plates showing arrangement of chromosomes, 

 from PAYNE and ROBERTSON 



Telophase in pollen division of Paris, after BOLLES LEE . 



Diagram of eggs segmenting normally and compressed in 

 glass tubes 



Tripolar and quadripolar spindles in Echinoid eggs, after 

 GRAY 



Diagrams of 

 GREGOIRE 



spermatogenesis and oogenesis, after 



9- 



ii. 



12. 



Types of Insect ovarian tubes, after KORSCHELT and 

 HEIDER 



Stages in the maturation of the egg of the Saw-fly 

 Nematus ......... 



Early development of the egg of Platygaster, showing 

 origin of the trophamnion from the polar nuclei, 

 after SILVESTRI and MARCHAL .... 



Chromosomes of Biston hirtarius and Nyssiazonaria, from 

 HARRISON and DONCASTER . . . 



Diagram of chromosome division in somatic and matura- 

 tion mitoses 



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