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Transactions of the Society. 



The process of dictyokinesis has been described in the follow- 

 ing : — Cells of Descemet's membrane of mammalian eye (Deinecka, 

 ^S) ; eight species of Pulmonate Mollusca* (Gatenby, 17) ; thyroid 

 gland cells of mammals (Cajal, 10) ; Paludina (Perroncito and 

 Gatenby, 17 and 22) ; Lepidoptera (Gatenby, 17), Argas (Casteel, 

 24). I have also observed dictyokinesis in many somatic cells of 

 Triton and Eana, but my results have not yet been published, and 

 are much like those of Cajal on the thyroid gland. 



In fig, 14 is drawn a type of dictyokinesis in which the Golgi 

 reticulum has broken into more or less irregular granules, which 

 keep around the zone of the amphiaster, but not necessarily around 

 the asters ; this type is common in vertebrate gland cells. 



In figs. 11-14 rare cases of chondrokinesis or dictyokinesis are 

 given. Fig. 11 is that of the typic spermatocyte of Paludina 

 vivipara, where the mitochondria are few and large and have 

 become constricted in the middle so that each cell gets one half of 



the large mitochondrium (17). Pig. 12 is Wilson's case in the 

 spermatocyte of the scorpion Centrurus, where the mitochondria 

 are in the form of a single ring which splits into four, and each 

 spermatid cell gets one portion of the ring {27). Pig. 13 is that of 

 the segmenting ovum (Limnaea). The Golgi rods (G) lie inert in 

 the cytoplasm just like the mitochondria, and do not keep around 

 the asters of the segmentation spindle {17, 24). Possibly all eggs 

 (as well as some spermatocytes, etc.) undergo this sort of dictyo- 

 kinesis and chondrokinesis. 



It is to be noticed that the process of dictyokinesis and chondro- 

 kinesis is much less exact than that of karyokinesis. In fig. 7 

 the chromosomes are split longitudinally and not merely sorted 

 oiit into two portions containing undivided elements, as occurs 

 with the mitochondria and Golgi apparatus. These facts, which 

 have been treated at length in other papers {17), should be borne in 

 mind by those who would consider that the mitochondria are in 



* See also Murray, Zool. Jahrb., Bd. xi. 



