The Identification of Intracelhdar Structures. 99 



filamentous or rod-like, generally very numerous elements, strewn 

 through the cytoplasm of cells, and that they have been found in 

 all plant and animal cells carefully studied by experts. There may 

 be rare exceptions where no mitochondria are present, but this is 

 due to the fact that differentiation has for some unknown reason 

 caused the presence of mitochondria to be unnecessary ; one such 

 case as this is the duct-cells of the rabbit's liver, and of several 

 other glands in vertebrates. 



Karyokinesis, Dictyokinesis and Chondkokinesis. 



Certain Italian workers {12, 33) have referred to the Golgi rod 

 or batonette as a " dictyosome," and Perroncito has suggested that 

 the process of the sorting out of the " dictyosomes " or rods between 

 the daughter-cells during cell-division should be called " dictyo- 

 kinesis." In my previous papers I have entered into the question 

 of dictyokinesis in Pulmonate Mollusca(i7) and Lepidoptera (17). 

 In figs. 4-14 I have drawn diagram matically the process of dictyo- 

 kinesis ; these figures would apply to all the known examples 

 and varieties of dictyokinesis. In fig. 4 the rods G lie upon the 

 sphere or archoplasm c ; the centrosome divides and the arrange- 

 ment of the (thirteen) rods becomes altered ; each centrosome 

 attracts to it about half of the whole rods as in fig. 5 ; the left 

 aster has seven of the rods, the right only six ; in fig. 6 this is more 

 easily seen. The rods keep around the amphiastral figure. In 

 figs. 7, 8, 9 and 10 subsequent stages are shown. In figs. 9 

 and 10 the sphere or archoplasm is reforming, after its dissolution 

 in fig. 5. 



In cell-division the mitochondria are also distributed between 

 the two daughter-cells ; like the Golgi elements, and unlike the 

 chromosomes, they are only sorted out haphazardly between the 

 new cells. This sorting-out process has been called chondrokinesis, 

 taking the part x^vSpo'i (a grain) of the words " mitochondrium 

 chondriokont or chondriosome," and the word " kinesis." Examina- 

 tion of figs. 4-10 shows that the mitochondria lie inert in the 

 cytoplasm and are passively distributed between the daughter- 

 cells. In these descriptions of dictyokinesis and chondrokinesis I 

 have made no mention of the fact that some staining change comes 

 over both chondriokonts or mitochondria and Golgi rods or granules 

 during the process of cell-division (17). With reference to karo- 

 kinesis, or the division of the nucleus, it is hardly necessary to 

 explain figs. 4-10, as the process has been described in text-books 

 such as that of Wilson on the " Cell." In figs. 6 and 7 the plasmo- 

 some and karyosome are seen to degenerate and to become reformed 

 in fig. 10. 



