4-IO ELMER L. SHAFFER. 



the resting nuclei of the old follicle-cells, it is very noticeable that 

 they are very poor in chromatin content, all the basichromatin 

 being accumulated in one or two small masses (nucleoli). When 

 such cells prepare for mitosis, the chromosomes which are re- 

 constituted are correspondingly poor in chromatin. However, 

 the linin basis of the chromosomes is still present and conse- 

 quently the number and size relations of the chromosomes is 

 maintained. This, I believe, gives added evidence to the view 

 previously expressed (Shaffer, '20) that the linin is the morpho- 

 logically stable substance which maintains the chromosomal 

 organization and structure. 



(r) Embryonic Cells. Although a number of the developing 

 eggs of Cicada were collected, I was unable to obtain good 

 material for a study of the chromosomes due to the difficulties 

 in sectioning. The eggs were so full of yolk that it was possible 

 to cut them only by imbedding by the celloidin-paraffine method. 



Figure 9 is that of a metaphase plate of a cell from the blasto- 

 derm showing 20 chromosomes, and hence of the female type. 

 The chromosome pairs AA, BB, and CC can be distinguished 

 as in the other diploid nuclei. While I have been unable to 

 make an exhaustive study of the chromosomes of the embryonic 

 cells, yet I have found no variations in the chromosome numbers 

 or in their size relations. 



(d) Somatic Cells. On dissecting the female locusts to remove 

 the ovaries, a number of round, brown-pigmented bodies re- 

 sembling eggs were found in the abdomen. On sectioning these 

 it was found that they were of a glandular nature and are perhaps 

 concerned in the secretion of adhesive materials for the eggs. 

 In a small cap of cells which lies at one end of these glandular 

 bodies, mitotic figures were found in abundance. There are 

 alw r ays 20 chromosomes which show similar size relations to 

 the diploid chromosome groups previously described. After 

 mitotic division of the nucleus the cell-body fails to divide, 

 resulting in the formation of binucleate and multinucleate cells. 

 At the time of division of such multinucleate cells, typical tri- 

 asters are formed (Fig. 52). In the telophase of such a division, 

 the tripartite daughter nuclei reconstruct to form six separate 

 nuclei, the cell-body again failing to divide. At this time the 



