Kofokl^Swezy : Triclwmitus termitidis 35 



BINARY AND MULTIPLE FISSION 



Both of these processes take place frequently in Trichnmitus. 

 There is much evidence of a high death rate in this species within the 

 digestive tract of its host. This is compensated for by rapid multi- 

 plication. For this also there is abundant evidence in our material. 



The distinction between stages of binary and multiple fission is 

 not readily made in all eases in early stages. The earliest phases of 

 both are obviously the same in mitotic phenomenon. Binucleate Plas- 

 modia may lead on to further division when prophases appear in their 

 nuclei (pi. 4, fig. 23). When, however, no later prophase phenomena 

 are evident and the organism is not unusually lai'ge (pi. 4, fig. 36) 

 binary fission only may be expected. It also occurs in the small cysts 

 (pi. 4, fig. 26) and small free forms ( pi. 4, fig. 29). 



Multiple fission, on the other hand, occurs in large individuals and 

 leads to the formation of, presumably, eight-celled plasmodia. 



One such large Plasmodium with six constituent zooids is seen in 

 plate 4, fig. 28. It is possibly in plasmotomy and has lost two of its 

 members. Not all multiple fission plasmodia are as large as this. 

 Smaller ones, in which the first division has been completed and the 

 second initiated, are frequently found (pi. 4, figs. 23, 25, 35). 



The process is one of three repeated divisions prior to plasmotomy 

 with the formation of an eight-nucleate somatella and its subsequent 

 disintegration into its constituent zooids by their detachment singly 

 or in groups. These somatella or plasmodial stages are exceedingly 

 mobile and the constituent individuals shift about without seeming 

 order of arrangement. The uncoordinated movements of the powerful 

 neuromotor apparatus of the individual zooids finally result in their 

 separation. The connecting paradesmoses are lost long before this 

 separation. 



No trace of unequivocal sexual phenomena has been detected. 

 Large and small individuals simulating macrogametes and micro- 

 gametes and gametocytes are present. Binucleate individuals without 

 evidence of recent division occur (pi. 4, fig. 36), simulating zygotes, 

 and similar associations are found in cysts (pi. 4, fig. 26). There is, 

 however, no evidence of maturation divisions leading to gamete forma- 

 tion, no sexual behavior detected, and no evidence of the fusion of 

 gametic nuclei. In the absence of such evidence any conclusions as 

 to the possibility of sexual reproduction in this organism must be held 

 in abeyance. 



