

No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 429 



longitudinal axis, at about its middle ; in the other case 

 (Fig. 129) the body was plainly biscuit-shaped, with a well- 

 marked medial constriction : these would probably represent 

 respectively successive stages of division. 



The various stages found would show the metamorphoses of 

 these structures to be as follows : in the medium-sized nuclei, 

 those in which they first appear, there is only one to a nucleus. 

 This one increases in size up to a variable point, when it begins 

 to divide, producing two daughter-bodies, which are not always 

 of equal size. One or both of these bodies may now divide 

 again, resulting in the formation of (respectively) three or four 

 bodies. Since, however, the four bodies sometimes found in 

 the larger nuclei are often quite unequal in size, we must 

 assume : (i) either that the divisions have been very unequal, 

 and each daughter-body had divided ; or (2) that after the first 

 division, which may or may not have resulted in unequal 

 daughter-bodies, only one of the latter divides further, and it 

 divides once, and one of its products divides once. It is to be 

 noted that the number, the size, and the time of the division 

 of these bodies stand in no regular relation to the size of the 

 nucleus. Thus in one small nucleus (Fig. 128) three were 

 already present, so that here two divisions must have taken 

 place; while in some much larger nuclei (Figs. 130 and 133) a 

 single, much larger one was present, which showed no signs 

 of division. In the larger nuclei these bodies are often quite 

 irregular in form ; may this increasing irregularity portend 

 an on-coming dissolution or other degeneration } They were 

 found, as remarked above, in the ova of only one of the three 

 individuals of this species examined, though in all three indi- 

 viduals the stages of egg development were very much alike ; 

 in the single individual in which they occurred they were not 

 present in all the larger eggs. Their whole appearance and con- 

 sistency show that they are not artefacts (the fixation was with 

 hot aqueous corrosive sublimate), and they have no resem- 

 blance to any parasitic organisms, as e.g., Protozoa, with which 

 I am acquainted. Nor can they be centrosomes nor true nucle- 

 oli, and stand in no apparent relation to the nucleoli. In a 

 single case I found two nucleoli enclosed by one of these bodies ; 



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