GAS GLANDS OF SOAIE TELEOSTEAX FISUES. 211 



in the Kynoytial masses at tlio base of tlie gland. In cells of 

 intermediate size and in giant cells ninitosis occurs, as I have 

 already state 1. Figure 64 illustrates several phases of direct 

 division, l)ut L must also mention that the huge nuclei of many 

 giant cells, like those of myeloplaxes of bone-marrow, appear 

 sometimes to divide into several — three, four, or more — nuclear 

 lumps at a single division, though I do not remember to have 

 seen cells containing more than two nuclei in the resting condition. 

 Tiiese various fa.cts considered collectively seem to suggest that in 

 cases like Zeus the initial unilaminar epithelium of the bladder 

 wall must contain nuclei of various sizes and that the nuclei of 

 each size, associated with cytoplasm, multiply in order to produce 

 the massive gland of the adult fish. As the nuclei become more 

 numerous they migrate from the centime of proliferation, the small 

 nuclei occupying cytoplasm vvhich, owing to the size of the nuclei, 

 becomes subdivided up into small areas, the lai-ger nuclei, fewer 

 in number, also occupying cytoplasm which, owing to the superior 

 size of the nuclei and their slow rate of division, remains to a 

 large extent unsubdivided, so forming the giant cells round the 

 giant nuclei. There is no evidence in my preparations of giant 

 cells splitting up into groups of small cells. The small cells 

 multiply by mitotic division, and amitosis is only found in the 

 case of the larger nuclei — those of the giant cells and larger 

 intermediate cells. As to the origin of the giant nuclei I can 

 give no infoi-mation. It is stated that the cells of bone- marrow 

 and some glands divide mitotically after undergoing amitosis, so 

 that there is no theoretical objection to supposing that the small 

 syncytial niiclei have been produced, as Deineka supposes, by 

 amitotic subdivision of giant nuclei, but I have never seen any 

 appearance of this taking place and I very much doubt its 

 occuri-ence : nearly all the appeai'ances of amitosis which I have 

 observed have been in connection with the nuclei of giant cells, 

 i. e. far away from the syncytia. As to the reason for amitosis 

 occurring in connection with giant nuclei, it is only possible to 

 readvance the old suggestion that it is a prelude to degeneration. 

 The gas gland is in Zeus and presumably other types constantly 

 being regenerated at its base, and therefore there is ground for 

 supposing that cells at the periphery of the gland become used up 

 and degeneration is the natural result of this. But this suj-)pose<l 

 degeneration of the cells has nothing to do with the violent 

 decomposition of cell-substance assumed to occui' by Nusliaum &. 

 Reis in connection with the production of gas — a phenomenon for 

 the existence of which I can find no evidence and in which I 

 fpiite disbelieve. 



Gadus morrhua. 



The "red body"' of the Cod* is knoAvn to every student of 



comparative anatom}' as a large red mass situated antei'iorly in the 



bladder. As Vincent k Barnes (75) say, the free surface of the 



" red gland '' shows " many small clubbed processes, packed 



* I used common "CoiUing'' caught off Deal. 



